【转】linux设备驱动之MMC SD卡——核心层简单分析
原文网址：http://blog.chinaunix.net/uid-28685940-id-3889878.html
/*************************************************************************************************************************************/
/* bus.c */
/*
* linux/drivers/mmc/core/bus.c
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
* Copyright (C) 2007 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* MMC card bus driver model
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include "core.h"
#include "sdio_cis.h"
#include "bus.h"
#define dev_to_mmc_card(d) container_of(d, struct mmc_card, dev)
#define to_mmc_driver(d) container_of(d, struct mmc_driver, drv)
/*显示mmc类型 */
static ssize_t mmc_type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mmc_card *card = dev_to_mmc_card(dev);
switch (card->type) {
case MMC_TYPE_MMC:
return sprintf(buf, "MMC\n");
case MMC_TYPE_SD:
return sprintf(buf, "SD\n");
case MMC_TYPE_SDIO:
return sprintf(buf, "SDIO\n");
default:
return -EFAULT;
}
}
static struct device_attribute mmc_dev_attrs[] = { /* 设备属性文件 */
__ATTR(type, S_IRUGO, mmc_type_show, NULL),
__ATTR_NULL,
};
/*
* This currently matches any MMC driver to any MMC card - drivers
* themselves make the decision whether to drive this card in their
* probe method.
*/
/* 匹配函数 */
static int mmc_bus_match(struct device *dev, struct device_driver *drv)
{
return 1;
}
/* 热插拔事件处理函数 */
static int
mmc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct mmc_card *card = dev_to_mmc_card(dev);
const char *type;
int retval = 0;
switch (card->type) {
case MMC_TYPE_MMC:
type = "MMC";
break;
case MMC_TYPE_SD:
type = "SD";
break;
case MMC_TYPE_SDIO:
type = "SDIO";
break;
default:
type = NULL;
}
if (type) {
retval = add_uevent_var(env, "MMC_TYPE=%s", type); /* 添加ueven环境变量 */
if (retval)
return retval;
}
retval = add_uevent_var(env, "MMC_NAME=%s", mmc_card_name(card));
if (retval)
return retval;
/*
* Request the mmc_block device. Note: that this is a direct request
* for the module it carries no information as to what is inserted.
*/
retval = add_uevent_var(env, "MODALIAS=mmc:block");
return retval;
}
/* 探测函数 */
static int mmc_bus_probe(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = dev_to_mmc_card(dev);
return drv->probe(card); /* 调用struct mmc_driver 的probe函数来挂起设备----由此可见probe函数必须提供 */
}
/* 移除函数 */
static int mmc_bus_remove(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = dev_to_mmc_card(dev);
drv->remove(card); /* 调用struct mmc_driver 的remove函数来挂起设备----由此可见remove函数必须提供 */
return 0;
}
/* 挂起函数 */
static int mmc_bus_suspend(struct device *dev, pm_message_t state)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = dev_to_mmc_card(dev);
int ret = 0;
if (dev->driver && drv->suspend)
ret = drv->suspend(card, state); /* 调用struct mmc_driver 的suspend函数来挂起设备 */
return ret;
}
/* 恢复函数 */
static int mmc_bus_resume(struct device *dev)
{
struct mmc_driver *drv = to_mmc_driver(dev->driver);
struct mmc_card *card = dev_to_mmc_card(dev);
int ret = 0;
if (dev->driver && drv->resume)
ret = drv->resume(card); /* 调用struct mmc_driver 的resume函数来恢复设备 */
return ret;
}
static struct bus_type mmc_bus_type = { /* 总线类型 */
.name = "mmc", /* 总线类型为mmc，会在/sys/bus目录下创建一个mmc目录 */
.dev_attrs = mmc_dev_attrs, /* 设备属性 */
.match = mmc_bus_match, /* 匹配函数 */
.uevent = mmc_bus_uevent, /* 热插拔事件处理函数 */
.probe = mmc_bus_probe, /* 探测函数 */
.remove = mmc_bus_remove, /* 移除函数 */
.suspend = mmc_bus_suspend, /* 挂起函数 */
.resume = mmc_bus_resume, /* 恢复函数 */
};
int mmc_register_bus(void)
{
return bus_register(&mmc_bus_type); /* 向设备模型核心注册一条总线 */
}
void mmc_unregister_bus(void)
{
bus_unregister(&mmc_bus_type); /* 注销总线 */
}
/**
* mmc_register_driver - register a media driver
* @drv: MMC media driver
*/
/* 注册mmc驱动 */
int mmc_register_driver(struct mmc_driver *drv)
{
drv->drv.bus = &mmc_bus_type;
return driver_register(&drv->drv); /* 向驱动模型核心注册驱动 */
}
EXPORT_SYMBOL(mmc_register_driver);
/**
* mmc_unregister_driver - unregister a media driver
* @drv: MMC media driver
*/
/* 注销mmc驱动 */
void mmc_unregister_driver(struct mmc_driver *drv)
{
drv->drv.bus = &mmc_bus_type;
driver_unregister(&drv->drv);
}
EXPORT_SYMBOL(mmc_unregister_driver);
/* 释放SD卡描述结构体----struct mmc_card */
static void mmc_release_card(struct device *dev)
{
struct mmc_card *card = dev_to_mmc_card(dev);
sdio_free_common_cis(card);
if (card->info)
kfree(card->info);
kfree(card);
}
/*
* Allocate and initialise a new MMC card structure.
*/
/* 分配并初始化一个SD卡描述结构体--struct mmc_card- */
struct mmc_card *mmc_alloc_card(struct mmc_host *host, struct device_type *type)
{
struct mmc_card *card;
card = kzalloc(sizeof(struct mmc_card), GFP_KERNEL); /* 分配一个struct mmc_card结构体 */
if (!card)
return ERR_PTR(-ENOMEM);
/* 初始化其成员 */
card->host = host;
device_initialize(&card->dev); /* 初始化设备 */
card->dev.parent = mmc_classdev(host);
card->dev.bus = &mmc_bus_type;
card->dev.release = mmc_release_card;
card->dev.type = type;
return card;
}
/*
* Register a new MMC card with the driver model.
*/
/* 注册一个MMC卡到驱动模型 */
int mmc_add_card(struct mmc_card *card)
{
int ret;
const char *type;
dev_set_name(&card->dev, "%s:%04x", mmc_hostname(card->host), card->rca); /* 设置设备的名字 */
switch (card->type) {
case MMC_TYPE_MMC:
type = "MMC";
break;
case MMC_TYPE_SD:
type = "SD";
if (mmc_card_blockaddr(card))
type = "SDHC";
break;
case MMC_TYPE_SDIO:
type = "SDIO";
break;
default:
type = "?";
break;
}
if (mmc_host_is_spi(card->host)) { /* 如果mmc主机控制器使用的是SPI总线 */
printk(KERN_INFO "%s: new %s%s card on SPI\n",
mmc_hostname(card->host),
mmc_card_highspeed(card) ? "high speed " : "",
type);
} else {
printk(KERN_INFO "%s: new %s%s card at address %04x\n",
mmc_hostname(card->host),
mmc_card_highspeed(card) ? "high speed " : "",
type, card->rca);
}
ret = device_add(&card->dev); /* 向设备驱动模型核心添加一个设备 */
if (ret)
return ret;
#ifdef CONFIG_DEBUG_FS
mmc_add_card_debugfs(card);
#endif
mmc_card_set_present(card);
return 0;
}
/*
* Unregister a new MMC card with the driver model, and
* (eventually) free it.
*/
/*注销一个MMC卡从驱动模型 */
void mmc_remove_card(struct mmc_card *card)
{
#ifdef CONFIG_DEBUG_FS
mmc_remove_card_debugfs(card);
#endif
if (mmc_card_present(card)) {
if (mmc_host_is_spi(card->host)) {
printk(KERN_INFO "%s: SPI card removed\n",
mmc_hostname(card->host));
} else {
printk(KERN_INFO "%s: card %04x removed\n",
mmc_hostname(card->host), card->rca);
}
device_del(&card->dev); /* 从设备驱动模型核心删除 */
}
put_device(&card->dev); /* 减小设备的引用计数 */
}
/*************************************************************************************************************************************/
/* core.h */
/*
* linux/drivers/mmc/core/core.h
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
* Copyright 2007 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*
SD卡内部结构:
______________________________________________________________________________
/ -- -- -- -- -- -- -- -- |
/ -- || || || || || || || || |
/ || || || || || || || || || |
/ || -- -- -- -- -- -- -- -- |
| -- | | | | | | | | |
| ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ |
| DATA2 CD/DATA3 CMD GND VDD CLK GND DATA0 DATA1 |
| |
| ---------- ------------------------------------- |
| |OCR[31:0]|<---->| | |
| ---------- | | |
| ---------- | | |
| |CID[127:0]|<--> | | |
| ---------- | | |
| ----------- | Card | |
| |RCA[15:0]|<--->| interface | |
| ----------- | controller | |
| ----------- | | |
| |DSR[15:0]|<--->| | ------ |
| ----------- | | | P | |
| ----------- | | | o | |
| |CSD[127:0]|<-->| |<----- | w | |
| ----------- | | | e | |
| ----------- | | | r | |
| |SCR[63:0] |<--> | | | | |
| -------------------------------------- | o | |
| | n | |
| | | |
| --------------------------------------------------------------- | d | |
| | Memory core interface reset|<--| e | |
| --------------------------------------------------------------- | t | |
| ↑ | e | |
| | | c | |
| | | t | |
| | | i | |
| | | o | |
| ↓ | n | |
| ----------------------------------------------------------------- ------ |
| | | |
| | | |
| | | |
| | | |
| | Memory core | |
| | |
| | | |
| | | |
| | | |
| ---------------------------------------------------------------- |
_______________________________________________________________________________________
OCR寄存器:操作条件寄存器
SCR寄存器:SD配置寄存器----保存卡的特殊功能信息
CSD寄存器:卡的特殊数据寄存器----卡的操作条件信息
DSR寄存器:驱动配置寄存器----用来配置卡的输出驱动
RCA寄存器:卡的相对地址----本地系统中卡的地址，动态变化，在主机初始化的时候确定
CID寄存器:卡的识别序列号
*/
#ifndef _MMC_CORE_CORE_H
#define _MMC_CORE_CORE_H
#include <linux/delay.h>
#define MMC_CMD_RETRIES 3
struct mmc_bus_ops { /* mmc总线操作函数集 */
void (*remove)(struct mmc_host *); /* 移除 */
void (*detect)(struct mmc_host *); /* 探测 */
void (*suspend)(struct mmc_host *); /* 挂起 */
void (*resume)(struct mmc_host *); /* 恢复 */
};
void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
void mmc_detach_bus(struct mmc_host *host);
void mmc_set_chip_select(struct mmc_host *host, int mode);
void mmc_set_clock(struct mmc_host *host, unsigned int hz);
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode);
void mmc_set_bus_width(struct mmc_host *host, unsigned int width);
u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
void mmc_set_timing(struct mmc_host *host, unsigned int timing);
/* 延时ms毫秒 */
static inline void mmc_delay(unsigned int ms)
{
if (ms < 1000 / HZ) {
cond_resched();
mdelay(ms);
} else {
msleep(ms);
}
}
void mmc_rescan(struct work_struct *work);
void mmc_start_host(struct mmc_host *host);
void mmc_stop_host(struct mmc_host *host);
int mmc_attach_mmc(struct mmc_host *host, u32 ocr);
int mmc_attach_sd(struct mmc_host *host, u32 ocr);
int mmc_attach_sdio(struct mmc_host *host, u32 ocr);
extern int use_spi_crc;
/* Debugfs information for hosts and cards */
void mmc_add_host_debugfs(struct mmc_host *host);
void mmc_remove_host_debugfs(struct mmc_host *host);
void mmc_add_card_debugfs(struct mmc_card *card);
void mmc_remove_card_debugfs(struct mmc_card *card);
#endif
/*************************************************************************************************************************************/
/* core.c */
/*
* linux/drivers/mmc/core/core.c
*
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
* Copyright (C) 2005-2008 Pierre Ossman, All Rights Reserved.
* MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <linux/leds.h>
#include <linux/scatterlist.h>
#include <linux/log2.h>
#include <linux/regulator/consumer.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sd.h>
#include "core.h"
#include "bus.h"
#include "host.h"
#include "sdio_bus.h"
#include "mmc_ops.h"
#include "sd_ops.h"
#include "sdio_ops.h"
static struct workqueue_struct *workqueue;
/*
* Enabling software CRCs on the data blocks can be a significant (30%)
* performance cost, and for other reasons may not always be desired.
* So we allow it it to be disabled.
*/
int use_spi_crc = 1;
module_param(use_spi_crc, bool, 0);
/*
* Internal function. Schedule delayed work in the MMC work queue.
*/
/* 调度mmc工作队列上延时工作 */
static int mmc_schedule_delayed_work(struct delayed_work *work,
unsigned long delay)
{
return queue_delayed_work(workqueue, work, delay);
}
/*
* Internal function. Flush all scheduled work from the MMC work queue.
*/
static void mmc_flush_scheduled_work(void)
{
flush_workqueue(workqueue);
}
/**
* mmc_request_done - finish processing an MMC request
* @host: MMC host which completed request
* @mrq: MMC request which request
*
* MMC drivers should call this function when they have completed
* their processing of a request.
*/
/* 完成处理一个mmc请求 */
void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
struct mmc_command *cmd = mrq->cmd;
int err = cmd->error;
if (err && cmd->retries && mmc_host_is_spi(host)) {
if (cmd->resp[0] & R1_SPI_ILLEGAL_COMMAND)
cmd->retries = 0;
}
if (err && cmd->retries) {
pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
mmc_hostname(host), cmd->opcode, err);
cmd->retries--;
cmd->error = 0;
host->ops->request(host, mrq); /* 如果出现错误并且重复次数不为0则再次调用请求处理函数来处理请求 */
} else {
led_trigger_event(host->led, LED_OFF);
pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n",
mmc_hostname(host), cmd->opcode, err,
cmd->resp[0], cmd->resp[1],
cmd->resp[2], cmd->resp[3]);
if (mrq->data) {
pr_debug("%s: %d bytes transferred: %d\n",
mmc_hostname(host),
mrq->data->bytes_xfered, mrq->data->error);
}
if (mrq->stop) {
pr_debug("%s: (CMD%u): %d: %08x %08x %08x %08x\n",
mmc_hostname(host), mrq->stop->opcode,
mrq->stop->error,
mrq->stop->resp[0], mrq->stop->resp[1],
mrq->stop->resp[2], mrq->stop->resp[3]);
}
if (mrq->done)
mrq->done(mrq); /* 如果 struct mmc_request mrq->done有定义则调用该完成回调函数*/
}
}
EXPORT_SYMBOL(mmc_request_done);
/* 开始一个请求 */
static void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
#ifdef CONFIG_MMC_DEBUG
unsigned int i, sz;
struct scatterlist *sg;
#endif
pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
mmc_hostname(host), mrq->cmd->opcode,
mrq->cmd->arg, mrq->cmd->flags);
if (mrq->data) {
pr_debug("%s: blksz %d blocks %d flags %08x "
"tsac %d ms nsac %d\n",
mmc_hostname(host), mrq->data->blksz,
mrq->data->blocks, mrq->data->flags,
mrq->data->timeout_ns / 1000000,
mrq->data->timeout_clks);
}
if (mrq->stop) {
pr_debug("%s: CMD%u arg %08x flags %08x\n",
mmc_hostname(host), mrq->stop->opcode,
mrq->stop->arg, mrq->stop->flags);
}
WARN_ON(!host->claimed);
led_trigger_event(host->led, LED_FULL);
mrq->cmd->error = 0;
mrq->cmd->mrq = mrq;
if (mrq->data) {
BUG_ON(mrq->data->blksz > host->max_blk_size);
BUG_ON(mrq->data->blocks > host->max_blk_count);
BUG_ON(mrq->data->blocks * mrq->data->blksz >
host->max_req_size);
#ifdef CONFIG_MMC_DEBUG
sz = 0;
for_each_sg(mrq->data->sg, sg, mrq->data->sg_len, i)
sz += sg->length;
BUG_ON(sz != mrq->data->blocks * mrq->data->blksz);
#endif
mrq->cmd->data = mrq->data;
mrq->data->error = 0;
mrq->data->mrq = mrq;
if (mrq->stop) {
mrq->data->stop = mrq->stop;
mrq->stop->error = 0;
mrq->stop->mrq = mrq;
}
}
host->ops->request(host, mrq); /* 调用host->ops->request请求处理函数来完成mmc协议的命令处理 */
}
/* 请求完成回调函数 */
static void mmc_wait_done(struct mmc_request *mrq)
{
complete(mrq->done_data); /* 唤醒等待队列中睡眠进程 */
}
/**
* mmc_wait_for_req - start a request and wait for completion
* @host: MMC host to start command
* @mrq: MMC request to start
*
* Start a new MMC custom command request for a host, and wait
* for the command to complete. Does not attempt to parse the
* response.
*/
/* 开始一个 请求并等待它完成 */
void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
DECLARE_COMPLETION_ONSTACK(complete);
mrq->done_data = &complete;
mrq->done = mmc_wait_done; /* 设置请求完成回调函数 */
mmc_start_request(host, mrq); /* 开始一个请求 */
wait_for_completion(&complete); /* 等待请求完成 */
}
EXPORT_SYMBOL(mmc_wait_for_req);
/**
* mmc_wait_for_cmd - start a command and wait for completion
* @host: MMC host to start command
* @cmd: MMC command to start
* @retries: maximum number of retries
*
* Start a new MMC command for a host, and wait for the command
* to complete. Return any error that occurred while the command
* was executing. Do not attempt to parse the response.
*/
/* 发送一个命令并等待它完成 */
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
struct mmc_request mrq;
WARN_ON(!host->claimed);
memset(&mrq, 0, sizeof(struct mmc_request));
memset(cmd->resp, 0, sizeof(cmd->resp));
cmd->retries = retries;
mrq.cmd = cmd; /* 指向命令 */
cmd->data = NULL; /* 没有数据 */
mmc_wait_for_req(host, &mrq); /* 开始一个请求并等待它完成 */
return cmd->error;
}
EXPORT_SYMBOL(mmc_wait_for_cmd);
/**
* mmc_set_data_timeout - set the timeout for a data command
* @data: data phase for command
* @card: the MMC card associated with the data transfer
*
* Computes the data timeout parameters according to the
* correct algorithm given the card type.
*/
/* 设置一个数据命令的超时时间 */
void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
{
unsigned int mult;
/*
* SDIO cards only define an upper 1 s limit on access.
*/
if (mmc_card_sdio(card)) { /* 如果是SDIO卡 */
data->timeout_ns = 1000000000;
data->timeout_clks = 0;
return;
}
/*
* SD cards use a 100 multiplier rather than 10
*/
mult = mmc_card_sd(card) ? 100 : 10;
/*
* Scale up the multiplier (and therefore the timeout) by
* the r2w factor for writes.
*/
if (data->flags & MMC_DATA_WRITE)
mult <<= card->csd.r2w_factor;
data->timeout_ns = card->csd.tacc_ns * mult;
data->timeout_clks = card->csd.tacc_clks * mult;
/*
* SD cards also have an upper limit on the timeout.
*/
if (mmc_card_sd(card)) {
unsigned int timeout_us, limit_us;
timeout_us = data->timeout_ns / 1000;
timeout_us += data->timeout_clks * 1000 /
(card->host->ios.clock / 1000);
if (data->flags & MMC_DATA_WRITE)
/*
* The limit is really 250 ms, but that is
* insufficient for some crappy cards.
*/
limit_us = 300000;
else
limit_us = 100000;
/*
* SDHC cards always use these fixed values.
*/
if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
data->timeout_ns = limit_us * 1000;
data->timeout_clks = 0;
}
}
/*
* Some cards need very high timeouts if driven in SPI mode.
* The worst observed timeout was 900ms after writing a
* continuous stream of data until the internal logic
* overflowed.
*/
if (mmc_host_is_spi(card->host)) {
if (data->flags & MMC_DATA_WRITE) {
if (data->timeout_ns < 1000000000)
data->timeout_ns = 1000000000; /* 1s */
} else {
if (data->timeout_ns < 100000000)
data->timeout_ns = 100000000; /* 100ms */
}
}
}
EXPORT_SYMBOL(mmc_set_data_timeout);
/**
* mmc_align_data_size - pads a transfer size to a more optimal value
* @card: the MMC card associated with the data transfer
* @sz: original transfer size
*
* Pads the original data size with a number of extra bytes in
* order to avoid controller bugs and/or performance hits
* (e.g. some controllers revert to PIO for certain sizes).
*
* Returns the improved size, which might be unmodified.
*
* Note that this function is only relevant when issuing a
* single scatter gather entry.
*/
unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz)
{
/*
* FIXME: We don't have a system for the controller to tell
* the core about its problems yet, so for now we just 32-bit
* align the size.
*/
sz = ((sz + 3) / 4) * 4;
return sz;
}
EXPORT_SYMBOL(mmc_align_data_size);
/**
* __mmc_claim_host - exclusively claim a host
* @host: mmc host to claim
* @abort: whether or not the operation should be aborted
*
* Claim a host for a set of operations. If @abort is non null and
* dereference a non-zero value then this will return prematurely with
* that non-zero value without acquiring the lock. Returns zero
* with the lock held otherwise.
*/
/* 声明主机控制器 */
int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
{
DECLARE_WAITQUEUE(wait, current); /* 定义并初始化一个等待队列 wait*/
unsigned long flags;
int stop;
might_sleep();
add_wait_queue(&host->wq, &wait); /* 将 host->wq添加到等待队列wait*/
spin_lock_irqsave(&host->lock, flags);
while (1) {
set_current_state(TASK_UNINTERRUPTIBLE); /* 设置当前进程的状态为TASK_UNINTERRUPTIBLE */
stop = abort ? atomic_read(abort) : 0; /* stop= abort? abort->counter:0?*/
if (stop || !host->claimed) /* 当stop=1或者 host->claimed=0时则继续循环*/
break;
spin_unlock_irqrestore(&host->lock, flags);
schedule(); /* 将进程调度处CPU----进程进入休眠 */
spin_lock_irqsave(&host->lock, flags);
}
set_current_state(TASK_RUNNING); /* 设置当前进程状态为TASK_RUNNING----CPU会调度该进程运行 */
if (!stop) /* 如果stop=0则设置 host->claimed = 1，否则*/
host->claimed = 1;
else
wake_up(&host->wq); /* 唤醒等待队列 host->wq上的进程*/
spin_unlock_irqrestore(&host->lock, flags);
remove_wait_queue(&host->wq, &wait); /* 将host->wq从wait中移除 */
return stop;
}
EXPORT_SYMBOL(__mmc_claim_host);
/**
* mmc_release_host - release a host
* @host: mmc host to release
*
* Release a MMC host, allowing others to claim the host
* for their operations.
*/
/* 释放主机 */
void mmc_release_host(struct mmc_host *host)
{
unsigned long flags;
WARN_ON(!host->claimed);
spin_lock_irqsave(&host->lock, flags);
host->claimed = 0;
spin_unlock_irqrestore(&host->lock, flags);
wake_up(&host->wq); /* 唤醒host->wq上的进程*/
}
EXPORT_SYMBOL(mmc_release_host);
/*
* Internal function that does the actual ios call to the host driver,
* optionally printing some debug output.
*/
/* 设置卡的I/O状态 */
static inline void mmc_set_ios(struct mmc_host *host)
{
struct mmc_ios *ios = &host->ios;
pr_debug("%s: clock %uHz busmode %u powermode %u cs %u Vdd %u "
"width %u timing %u\n",
mmc_hostname(host), ios->clock, ios->bus_mode,
ios->power_mode, ios->chip_select, ios->vdd,
ios->bus_width, ios->timing);
host->ops->set_ios(host, ios); /* 调用 struct mmc_host *host->ops->set_ios函数来对卡的I/O状态的进行设置*/
}
/*
* Control chip select pin on a host.
*/
/* 设置芯片片选 */
void mmc_set_chip_select(struct mmc_host *host, int mode)
{
host->ios.chip_select = mode;
mmc_set_ios(host);
}
/*
* Sets the host clock to the highest possible frequency that
* is below "hz".
*/
/* 设置主机控制器时钟 */
void mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
WARN_ON(hz < host->f_min);
if (hz > host->f_max)
hz = host->f_max;
host->ios.clock = hz;
mmc_set_ios(host);
}
/*
* Change the bus mode (open drain/push-pull) of a host.
*/
/* 设置总线模式 */
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
{
host->ios.bus_mode = mode;
mmc_set_ios(host);
}
/*
* Change data bus width of a host.
*/
/* 设置总线宽度 */
void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
{
host->ios.bus_width = width;
mmc_set_ios(host);
}
/**
* mmc_vdd_to_ocrbitnum - Convert a voltage to the OCR bit number
* @vdd: voltage (mV)
* @low_bits: prefer low bits in boundary cases
*
* This function returns the OCR bit number according to the provided @vdd
* value. If conversion is not possible a negative errno value returned.
*
* Depending on the @low_bits flag the function prefers low or high OCR bits
* on boundary voltages. For example,
* with @low_bits = true, 3300 mV translates to ilog2(MMC_VDD_32_33);
* with @low_bits = false, 3300 mV translates to ilog2(MMC_VDD_33_34);
*
* Any value in the [1951:1999] range translates to the ilog2(MMC_VDD_20_21).
*/
/* 将一个电压值转换为OCR寄存器的比特编号 */
static int mmc_vdd_to_ocrbitnum(int vdd, bool low_bits)
{
const int max_bit = ilog2(MMC_VDD_35_36);
int bit;
if (vdd < 1650 || vdd > 3600)
return -EINVAL;
if (vdd >= 1650 && vdd <= 1950)
return ilog2(MMC_VDD_165_195);
if (low_bits)
vdd -= 1;
/* Base 2000 mV, step 100 mV, bit's base 8. */
bit = (vdd - 2000) / 100 + 8;
if (bit > max_bit)
return max_bit;
return bit;
}
/**
* mmc_vddrange_to_ocrmask - Convert a voltage range to the OCR mask
* @vdd_min: minimum voltage value (mV)
* @vdd_max: maximum voltage value (mV)
*
* This function returns the OCR mask bits according to the provided @vdd_min
* and @vdd_max values. If conversion is not possible the function returns 0.
*
* Notes wrt boundary cases:
* This function sets the OCR bits for all boundary voltages, for example
* [3300:3400] range is translated to MMC_VDD_32_33 | MMC_VDD_33_34 |
* MMC_VDD_34_35 mask.
*/
/* 将一个电压等级转换为寄存器OCR的掩码 */
u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max)
{
u32 mask = 0;
if (vdd_max < vdd_min)
return 0;
/* Prefer high bits for the boundary vdd_max values. */
vdd_max = mmc_vdd_to_ocrbitnum(vdd_max, false);
if (vdd_max < 0)
return 0;
/* Prefer low bits for the boundary vdd_min values. */
vdd_min = mmc_vdd_to_ocrbitnum(vdd_min, true);
if (vdd_min < 0)
return 0;
/* Fill the mask, from max bit to min bit. */
while (vdd_max >= vdd_min)
mask |= 1 << vdd_max--;
return mask;
}
EXPORT_SYMBOL(mmc_vddrange_to_ocrmask);
#ifdef CONFIG_REGULATOR
/**
* mmc_regulator_get_ocrmask - return mask of supported voltages
* @supply: regulator to use
*
* This returns either a negative errno, or a mask of voltages that
* can be provided to MMC/SD/SDIO devices using the specified voltage
* regulator. This would normally be called before registering the
* MMC host adapter.
*/
/*返回支持的电压的掩码 */
int mmc_regulator_get_ocrmask(struct regulator *supply)
{
int result = 0;
int count;
int i;
count = regulator_count_voltages(supply);
if (count < 0)
return count;
for (i = 0; i < count; i++) {
int vdd_uV;
int vdd_mV;
vdd_uV = regulator_list_voltage(supply, i);
if (vdd_uV <= 0)
continue;
vdd_mV = vdd_uV / 1000;
result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
}
return result;
}
EXPORT_SYMBOL(mmc_regulator_get_ocrmask);
/**
* mmc_regulator_set_ocr - set regulator to match host->ios voltage
* @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
* @supply: regulator to use
*
* Returns zero on success, else negative errno.
*
* MMC host drivers may use this to enable or disable a regulator using
* a particular supply voltage. This would normally be called from the
* set_ios() method.
*/
/* 设置调节器使得其能够匹配 host->ios voltage*/
int mmc_regulator_set_ocr(struct regulator *supply, unsigned short vdd_bit)
{
int result = 0;
int min_uV, max_uV;
int enabled;
enabled = regulator_is_enabled(supply);
if (enabled < 0)
return enabled;
if (vdd_bit) {
int tmp;
int voltage;
/* REVISIT mmc_vddrange_to_ocrmask() may have set some
* bits this regulator doesn't quite support ... don't
* be too picky, most cards and regulators are OK with
* a 0.1V range goof (it's a small error percentage).
*/
tmp = vdd_bit - ilog2(MMC_VDD_165_195);
if (tmp == 0) {
min_uV = 1650 * 1000;
max_uV = 1950 * 1000;
} else {
min_uV = 1900 * 1000 + tmp * 100 * 1000;
max_uV = min_uV + 100 * 1000;
}
/* avoid needless changes to this voltage; the regulator
* might not allow this operation
*/
voltage = regulator_get_voltage(supply);
if (voltage < 0)
result = voltage;
else if (voltage < min_uV || voltage > max_uV)
result = regulator_set_voltage(supply, min_uV, max_uV);
else
result = 0;
if (result == 0 && !enabled)
result = regulator_enable(supply);
} else if (enabled) {
result = regulator_disable(supply);
}
return result;
}
EXPORT_SYMBOL(mmc_regulator_set_ocr);
#endif
/*
* Mask off any voltages we don't support and select
* the lowest voltage
*/
/* 选择电压
屏蔽不支持的电压并且选择最低的工作电压 */
u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
{
int bit;
ocr &= host->ocr_avail;
bit = ffs(ocr);
if (bit) {
bit -= 1;
ocr &= 3 << bit;
host->ios.vdd = bit;
mmc_set_ios(host);
} else {
pr_warning("%s: host doesn't support card's voltages\n",
mmc_hostname(host));
ocr = 0;
}
return ocr;
}
/*
* Select timing parameters for host.
*/
/* 为主机控制器选择时序参数 */
void mmc_set_timing(struct mmc_host *host, unsigned int timing)
{
host->ios.timing = timing;
mmc_set_ios(host);
}
/*
* Apply power to the MMC stack. This is a two-stage process.
* First, we enable power to the card without the clock running.
* We then wait a bit for the power to stabilise. Finally,
* enable the bus drivers and clock to the card.
*
* We must _NOT_ enable the clock prior to power stablising.
*
* If a host does all the power sequencing itself, ignore the
* initial MMC_POWER_UP stage.
*/
/* 上电 */
static void mmc_power_up(struct mmc_host *host)
{
int bit = fls(host->ocr_avail) - 1;
host->ios.vdd = bit;
if (mmc_host_is_spi(host)) {
host->ios.chip_select = MMC_CS_HIGH;
host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
} else {
host->ios.chip_select = MMC_CS_DONTCARE;
host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
}
host->ios.power_mode = MMC_POWER_UP;
host->ios.bus_width = MMC_BUS_WIDTH_1;
host->ios.timing = MMC_TIMING_LEGACY;
mmc_set_ios(host);
/*
* This delay should be sufficient to allow the power supply
* to reach the minimum voltage.
*/
mmc_delay(10);
host->ios.clock = host->f_min;
host->ios.power_mode = MMC_POWER_ON;
mmc_set_ios(host);
/*
* This delay must be at least 74 clock sizes, or 1 ms, or the
* time required to reach a stable voltage.
*/
mmc_delay(10);
}
/* 关闭电源 */
static void mmc_power_off(struct mmc_host *host)
{
host->ios.clock = 0;
host->ios.vdd = 0;
if (!mmc_host_is_spi(host)) {
host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
host->ios.chip_select = MMC_CS_DONTCARE;
}
host->ios.power_mode = MMC_POWER_OFF;
host->ios.bus_width = MMC_BUS_WIDTH_1;
host->ios.timing = MMC_TIMING_LEGACY;
mmc_set_ios(host);
}
/*
* Cleanup when the last reference to the bus operator is dropped.
*/
/* 释放总线操作函数 */
static void __mmc_release_bus(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(host->bus_refs);
BUG_ON(!host->bus_dead);
host->bus_ops = NULL;
}
/*
* Increase reference count of bus operator
*/
/* 增加 总线引用计数*/
static inline void mmc_bus_get(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->bus_refs++;
spin_unlock_irqrestore(&host->lock, flags);
}
/*
* Decrease reference count of bus operator and free it if
* it is the last reference.
*/
/* 减小总线引用计数 */
static inline void mmc_bus_put(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->bus_refs--;
if ((host->bus_refs == 0) && host->bus_ops)
__mmc_release_bus(host); /* 如果总线计数器为0并且总线操作函数集有定义则释放它 */
spin_unlock_irqrestore(&host->lock, flags);
}
/*
* Assign a mmc bus handler to a host. Only one bus handler may control a
* host at any given time.
*/
/* 将主机控制器和总线操作函数绑定 */
void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops)
{
unsigned long flags;
BUG_ON(!host);
BUG_ON(!ops);
WARN_ON(!host->claimed);
spin_lock_irqsave(&host->lock, flags);
BUG_ON(host->bus_ops);
BUG_ON(host->bus_refs);
host->bus_ops = ops;
host->bus_refs = 1;
host->bus_dead = 0;
spin_unlock_irqrestore(&host->lock, flags);
}
/*
* Remove the current bus handler from a host. Assumes that there are
* no interesting cards left, so the bus is powered down.
*/
/* 将总线和主机控制器分离 */
void mmc_detach_bus(struct mmc_host *host)
{
unsigned long flags;
BUG_ON(!host);
WARN_ON(!host->claimed);
WARN_ON(!host->bus_ops);
spin_lock_irqsave(&host->lock, flags);
host->bus_dead = 1; /* 标记总线已经释放 */
spin_unlock_irqrestore(&host->lock, flags);
mmc_power_off(host); /* 关闭电源 */
mmc_bus_put(host);
}
/**
* mmc_detect_change - process change of state on a MMC socket
* @host: host which changed state.
* @delay: optional delay to wait before detection (jiffies)
*
* MMC drivers should call this when they detect a card has been
* inserted or removed. The MMC layer will confirm that any
* present card is still functional, and initialize any newly
* inserted.
*/
/* 处理mmc插槽变化的状态 */
void mmc_detect_change(struct mmc_host *host, unsigned long delay)
{
#ifdef CONFIG_MMC_DEBUG
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
WARN_ON(host->removed);
spin_unlock_irqrestore(&host->lock, flags);
#endif
mmc_schedule_delayed_work(&host->detect, delay);
}
EXPORT_SYMBOL(mmc_detect_change);
/* 重新扫描 */
void mmc_rescan(struct work_struct *work)
{
struct mmc_host *host =
container_of(work, struct mmc_host, detect.work);
u32 ocr;
int err;
mmc_bus_get(host); /* 增加总线引用计数 */
if (host->bus_ops == NULL) { /* 如果总线操作函数集没有定义 */
/*
* Only we can add a new handler, so it's safe to
* release the lock here.
*/
mmc_bus_put(host); /* 减小总线引用计数 */
if (host->ops->get_cd && host->ops->get_cd(host) == 0) /* 如果 host->ops->get_cd函数有定义则调用它，如果该函数返回0则表示没有卡插入则退出*/
goto out;
mmc_claim_host(host); /* 声明一个主机控制器 */
mmc_power_up(host); /* 上电 */
mmc_go_idle(host); /* 进入idle邋状态 */
mmc_send_if_cond(host, host->ocr_avail);
/*
* First we search for SDIO...
*/
err = mmc_send_io_op_cond(host, 0, &ocr);
if (!err) {
if (mmc_attach_sdio(host, ocr))
mmc_power_off(host);
goto out;
}
/*
* ...then normal SD...
*/
err = mmc_send_app_op_cond(host, 0, &ocr);
if (!err) {
if (mmc_attach_sd(host, ocr))
mmc_power_off(host);
goto out;
}
/*
* ...and finally MMC.
*/
err = mmc_send_op_cond(host, 0, &ocr);
if (!err) {
if (mmc_attach_mmc(host, ocr))
mmc_power_off(host);
goto out;
}
mmc_release_host(host);
mmc_power_off(host);
} else {
if (host->bus_ops->detect && !host->bus_dead)
host->bus_ops->detect(host); /* 探测卡 */
mmc_bus_put(host);
}
out:
if (host->caps & MMC_CAP_NEEDS_POLL)
mmc_schedule_delayed_work(&host->detect, HZ);
}
/* 启动主机控制器 */
void mmc_start_host(struct mmc_host *host)
{
mmc_power_off(host); /* 打开电源 */
mmc_detect_change(host, 0); /* 探测 插槽是否发生变化*/
}
/* 停止主机控制器 */
void mmc_stop_host(struct mmc_host *host)
{
#ifdef CONFIG_MMC_DEBUG
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->removed = 1; /* 标记主机被移除 */
spin_unlock_irqrestore(&host->lock, flags);
#endif
cancel_delayed_work(&host->detect);
mmc_flush_scheduled_work();
mmc_bus_get(host);
if (host->bus_ops && !host->bus_dead) {
if (host->bus_ops->remove)
host->bus_ops->remove(host); /* 调用总线操作函数的移除函数 */
mmc_claim_host(host); /* 声明一个主机控制器 */
mmc_detach_bus(host); /* 将总线和主机控制器分离 */
mmc_release_host(host); /* 释放主机控制器 */
}
mmc_bus_put(host); /* 减小总线引用计数 */
BUG_ON(host->card);
mmc_power_off(host); /* 关闭电源 */
}
#ifdef CONFIG_PM
/**
* mmc_suspend_host - suspend a host
* @host: mmc host
* @state: suspend mode (PM_SUSPEND_xxx)
*/
/* 挂起主机控制器 */
int mmc_suspend_host(struct mmc_host *host, pm_message_t state)
{
cancel_delayed_work(&host->detect);
mmc_flush_scheduled_work();
mmc_bus_get(host); /* 增加总线引用计数 */
if (host->bus_ops && !host->bus_dead) {
if (host->bus_ops->suspend)
host->bus_ops->suspend(host); /* 如果总线操作函数集的挂起函数有定义则调用它 */
if (!host->bus_ops->resume) {
if (host->bus_ops->remove)
host->bus_ops->remove(host); /* 如果总线操作函数集的移除函数有定义则调用它 */
mmc_claim_host(host); /* 声明一个主机控制器 */
mmc_detach_bus(host); /* 将总线和主机控制器分离 */
mmc_release_host(host); /* 释放主机控制器 */
}
}
mmc_bus_put(host); /* 减小总线计数 */
mmc_power_off(host); /* 关闭电源 */
return 0;
}
EXPORT_SYMBOL(mmc_suspend_host);
/**
* mmc_resume_host - resume a previously suspended host
* @host: mmc host
*/
/* 恢复主机控制器 */
int mmc_resume_host(struct mmc_host *host)
{
mmc_bus_get(host); /* 增加引用计数 */
if (host->bus_ops && !host->bus_dead) {
mmc_power_up(host); /* 上电 */
mmc_select_voltage(host, host->ocr); /* 选择工作电压 */
BUG_ON(!host->bus_ops->resume);
host->bus_ops->resume(host); /* 调用 */
}
mmc_bus_put(host);
/*
* We add a slight delay here so that resume can progress
* in parallel.
*/
mmc_detect_change(host, 1);
return 0;
}
EXPORT_SYMBOL(mmc_resume_host);
#endif
static int __init mmc_init(void)
{
int ret;
workqueue = create_singlethread_workqueue("kmmcd"); /* 创建工作队列 */
if (!workqueue)
return -ENOMEM;
ret = mmc_register_bus(); /* 注册mmc总线 */
if (ret)
goto destroy_workqueue;
ret = mmc_register_host_class(); /* 注册主机类 */
if (ret)
goto unregister_bus;
ret = sdio_register_bus(); /* 注册SDIO总线 */
if (ret)
goto unregister_host_class;
return 0;
unregister_host_class:
mmc_unregister_host_class();
unregister_bus:
mmc_unregister_bus();
destroy_workqueue:
destroy_workqueue(workqueue);
return ret;
}
static void __exit mmc_exit(void)
{
sdio_unregister_bus();
mmc_unregister_host_class();
mmc_unregister_bus();
destroy_workqueue(workqueue);
}
subsys_initcall(mmc_init);
module_exit(mmc_exit);
MODULE_LICENSE("GPL");
/*************************************************************************************************************************************/
/* host.c*/
/*
* linux/drivers/mmc/core/host.c
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
* Copyright (C) 2007-2008 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* MMC host class device management
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/pagemap.h>
#include <linux/leds.h>
#include <linux/mmc/host.h>
#include "core.h"
#include "host.h"
#define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev)
/* 释放主机 */
static void mmc_host_classdev_release(struct device *dev)
{
struct mmc_host *host = cls_dev_to_mmc_host(dev);
kfree(host);
}
static struct class mmc_host_class = { /* 主机类 */
.name = "mmc_host", /* 类的名字为mmc_host */
.dev_release = mmc_host_classdev_release,
};
/* 注册一个主机类 */
int mmc_register_host_class(void)
{
return class_register(&mmc_host_class); /* 注册mmc_host_class类 */
}
/* 注销主机类 */
void mmc_unregister_host_class(void)
{
class_unregister(&mmc_host_class);
}
static DEFINE_IDR(mmc_host_idr);
static DEFINE_SPINLOCK(mmc_host_lock);
/**
* mmc_alloc_host - initialise the per-host structure.
* @extra: sizeof private data structure
* @dev: pointer to host device model structure
*
* Initialise the per-host structure.
*/
/* 分配一个struct mmc_host结构
参数extra为要分配的额外的内存*/
struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
{
int err;
struct mmc_host *host;
if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
return NULL;
host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL); /* 分配内存 */
if (!host)
return NULL;
spin_lock(&mmc_host_lock);
err = idr_get_new(&mmc_host_idr, host, &host->index);
spin_unlock(&mmc_host_lock);
if (err)
goto free;
/* 初始化struct mmc_host名字 */
dev_set_name(&host->class_dev, "mmc%d", host->index);
host->parent = dev;
host->class_dev.parent = dev;
host->class_dev.class = &mmc_host_class;
device_initialize(&host->class_dev); /* 初始化设备 */
spin_lock_init(&host->lock);
init_waitqueue_head(&host->wq); /* 初始化等待队列 */
INIT_DELAYED_WORK(&host->detect, mmc_rescan); /* 初始化延时工作结构 */
/*
* By default, hosts do not support SGIO or large requests.
* They have to set these according to their abilities.
*/
/* 设置它的成员 */
host->max_hw_segs = 1;
host->max_phys_segs = 1;
host->max_seg_size = PAGE_CACHE_SIZE;
host->max_req_size = PAGE_CACHE_SIZE;
host->max_blk_size = 512;
host->max_blk_count = PAGE_CACHE_SIZE / 512;
return host;
free:
kfree(host);
return NULL;
}
EXPORT_SYMBOL(mmc_alloc_host);
/**
* mmc_add_host - initialise host hardware
* @host: mmc host
*
* Register the host with the driver model. The host must be
* prepared to start servicing requests before this function
* completes.
*/
/* 添加一个mmc主机 */
int mmc_add_host(struct mmc_host *host)
{
int err;
WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
!host->ops->enable_sdio_irq);
led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
err = device_add(&host->class_dev); /* 向驱动模型核心添加一个设备 */
if (err)
return err;
#ifdef CONFIG_DEBUG_FS
mmc_add_host_debugfs(host);
#endif
mmc_start_host(host); /* 启动主机控制器 */
return 0;
}
EXPORT_SYMBOL(mmc_add_host);
/**
* mmc_remove_host - remove host hardware
* @host: mmc host
*
* Unregister and remove all cards associated with this host,
* and power down the MMC bus. No new requests will be issued
* after this function has returned.
*/
/* 移除一个mmc主机控制器 */
void mmc_remove_host(struct mmc_host *host)
{
mmc_stop_host(host);
#ifdef CONFIG_DEBUG_FS
mmc_remove_host_debugfs(host);
#endif
device_del(&host->class_dev); /* 从设备驱动模型核心删除一个设备 */
led_trigger_unregister_simple(host->led);
}
EXPORT_SYMBOL(mmc_remove_host);
/**
* mmc_free_host - free the host structure
* @host: mmc host
*
* Free the host once all references to it have been dropped.
*/
/* 释放主机控制器结构 */
void mmc_free_host(struct mmc_host *host)
{
spin_lock(&mmc_host_lock);
idr_remove(&mmc_host_idr, host->index);
spin_unlock(&mmc_host_lock);
put_device(&host->class_dev);
}
EXPORT_SYMBOL(mmc_free_host);
/*************************************************************************************************************************************/
/* mmc.c */
/*
* linux/drivers/mmc/core/mmc.c
*
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
* MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/mmc.h>
#include "core.h"
#include "bus.h"
#include "mmc_ops.h"
static const unsigned int tran_exp[] = {
10000, 100000, 1000000, 10000000,
0, 0, 0, 0
};
static const unsigned char tran_mant[] = {
0, 10, 12, 13, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
static const unsigned int tacc_exp[] = {
1, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
};
static const unsigned int tacc_mant[] = {
0, 10, 12, 13, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
#define UNSTUFF_BITS(resp,start,size) \
({ \
const int __size = size; \
const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
const int __off = 3 - ((start) / 32); \
const int __shft = (start) & 31; \
u32 __res; \
\
__res = resp[__off] >> __shft; \
if (__size + __shft > 32) \
__res |= resp[__off-1] << ((32 - __shft) % 32); \
__res & __mask; \
})
/*
* Given the decoded CSD structure, decode the raw CID to our CID structure.
*/
/* 解码CID寄存器 */
static int mmc_decode_cid(struct mmc_card *card)
{
u32 *resp = card->raw_cid;
/*
* The selection of the format here is based upon published
* specs from sandisk and from what people have reported.
*/
switch (card->csd.mmca_vsn) {
case 0: /* MMC v1.0 - v1.2 */
case 1: /* MMC v1.4 */
card->cid.manfid = UNSTUFF_BITS(resp, 104, 24);
card->cid.prod_name[0] = UNSTUFF_BITS(resp, 96, 8);
card->cid.prod_name[1] = UNSTUFF_BITS(resp, 88, 8);
card->cid.prod_name[2] = UNSTUFF_BITS(resp, 80, 8);
card->cid.prod_name[3] = UNSTUFF_BITS(resp, 72, 8);
card->cid.prod_name[4] = UNSTUFF_BITS(resp, 64, 8);
card->cid.prod_name[5] = UNSTUFF_BITS(resp, 56, 8);
card->cid.prod_name[6] = UNSTUFF_BITS(resp, 48, 8);
card->cid.hwrev = UNSTUFF_BITS(resp, 44, 4);
card->cid.fwrev = UNSTUFF_BITS(resp, 40, 4);
card->cid.serial = UNSTUFF_BITS(resp, 16, 24);
card->cid.month = UNSTUFF_BITS(resp, 12, 4);
card->cid.year = UNSTUFF_BITS(resp, 8, 4) + 1997;
break;
case 2: /* MMC v2.0 - v2.2 */
case 3: /* MMC v3.1 - v3.3 */
case 4: /* MMC v4 */
card->cid.manfid = UNSTUFF_BITS(resp, 120, 8);
card->cid.oemid = UNSTUFF_BITS(resp, 104, 16);
card->cid.prod_name[0] = UNSTUFF_BITS(resp, 96, 8);
card->cid.prod_name[1] = UNSTUFF_BITS(resp, 88, 8);
card->cid.prod_name[2] = UNSTUFF_BITS(resp, 80, 8);
card->cid.prod_name[3] = UNSTUFF_BITS(resp, 72, 8);
card->cid.prod_name[4] = UNSTUFF_BITS(resp, 64, 8);
card->cid.prod_name[5] = UNSTUFF_BITS(resp, 56, 8);
card->cid.serial = UNSTUFF_BITS(resp, 16, 32);
card->cid.month = UNSTUFF_BITS(resp, 12, 4);
card->cid.year = UNSTUFF_BITS(resp, 8, 4) + 1997;
break;
default:
printk(KERN_ERR "%s: card has unknown MMCA version %d\n",
mmc_hostname(card->host), card->csd.mmca_vsn);
return -EINVAL;
}
return 0;
}
/*
* Given a 128-bit response, decode to our card CSD structure.
*/
/* 解码CSD寄存器 */
static int mmc_decode_csd(struct mmc_card *card)
{
struct mmc_csd *csd = &card->csd;
unsigned int e, m, csd_struct;
u32 *resp = card->raw_csd;
/*
* We only understand CSD structure v1.1 and v1.2.
* v1.2 has extra information in bits 15, 11 and 10.
*/
csd_struct = UNSTUFF_BITS(resp, 126, 2);
if (csd_struct != 1 && csd_struct != 2) {
printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
mmc_hostname(card->host), csd_struct);
return -EINVAL;
}
csd->mmca_vsn = UNSTUFF_BITS(resp, 122, 4);
m = UNSTUFF_BITS(resp, 115, 4);
e = UNSTUFF_BITS(resp, 112, 3);
csd->tacc_ns = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
csd->tacc_clks = UNSTUFF_BITS(resp, 104, 8) * 100;
m = UNSTUFF_BITS(resp, 99, 4);
e = UNSTUFF_BITS(resp, 96, 3);
csd->max_dtr = tran_exp[e] * tran_mant[m];
csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);
e = UNSTUFF_BITS(resp, 47, 3);
m = UNSTUFF_BITS(resp, 62, 12);
csd->capacity = (1 + m) << (e + 2);
csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
return 0;
}
/*
* Read and decode extended CSD.
*/
/* 读取并且解码扩展的CSD寄存器 */
static int mmc_read_ext_csd(struct mmc_card *card)
{
int err;
u8 *ext_csd;
unsigned int ext_csd_struct;
BUG_ON(!card);
if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
return 0;
/*
* As the ext_csd is so large and mostly unused, we don't store the
* raw block in mmc_card.
*/
ext_csd = kmalloc(512, GFP_KERNEL);
if (!ext_csd) {
printk(KERN_ERR "%s: could not allocate a buffer to "
"receive the ext_csd.\n", mmc_hostname(card->host));
return -ENOMEM;
}
err = mmc_send_ext_csd(card, ext_csd);
if (err) {
/*
* We all hosts that cannot perform the command
* to fail more gracefully
*/
if (err != -EINVAL)
goto out;
/*
* High capacity cards should have this "magic" size
* stored in their CSD.
*/
if (card->csd.capacity == (4096 * 512)) {
printk(KERN_ERR "%s: unable to read EXT_CSD "
"on a possible high capacity card. "
"Card will be ignored.\n",
mmc_hostname(card->host));
} else {
printk(KERN_WARNING "%s: unable to read "
"EXT_CSD, performance might "
"suffer.\n",
mmc_hostname(card->host));
err = 0;
}
goto out;
}
ext_csd_struct = ext_csd[EXT_CSD_REV];
if (ext_csd_struct > 3) {
printk(KERN_ERR "%s: unrecognised EXT_CSD structure "
"version %d\n", mmc_hostname(card->host),
ext_csd_struct);
err = -EINVAL;
goto out;
}
if (ext_csd_struct >= 2) {
card->ext_csd.sectors =
ext_csd[EXT_CSD_SEC_CNT + 0] << 0 |
ext_csd[EXT_CSD_SEC_CNT + 1] << 8 |
ext_csd[EXT_CSD_SEC_CNT + 2] << 16 |
ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
if (card->ext_csd.sectors)
mmc_card_set_blockaddr(card);
}
switch (ext_csd[EXT_CSD_CARD_TYPE]) {
case EXT_CSD_CARD_TYPE_52 | EXT_CSD_CARD_TYPE_26:
card->ext_csd.hs_max_dtr = 52000000;
break;
case EXT_CSD_CARD_TYPE_26:
card->ext_csd.hs_max_dtr = 26000000;
break;
default:
/* MMC v4 spec says this cannot happen */
printk(KERN_WARNING "%s: card is mmc v4 but doesn't "
"support any high-speed modes.\n",
mmc_hostname(card->host));
goto out;
}
out:
kfree(ext_csd);
return err;
}
MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
card->raw_cid[2], card->raw_cid[3]);
MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
card->raw_csd[2], card->raw_csd[3]);
MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
static struct attribute *mmc_std_attrs[] = {
&dev_attr_cid.attr,
&dev_attr_csd.attr,
&dev_attr_date.attr,
&dev_attr_fwrev.attr,
&dev_attr_hwrev.attr,
&dev_attr_manfid.attr,
&dev_attr_name.attr,
&dev_attr_oemid.attr,
&dev_attr_serial.attr,
NULL,
};
static struct attribute_group mmc_std_attr_group = {
.attrs = mmc_std_attrs,
};
static struct attribute_group *mmc_attr_groups[] = {
&mmc_std_attr_group,
NULL,
};
static struct device_type mmc_type = {
.groups = mmc_attr_groups,
};
/*
* Handle the detection and initialisation of a card.
*
* In the case of a resume, "oldcard" will contain the card
* we're trying to reinitialise.
*/
/* 初始化卡 */
static int mmc_init_card(struct mmc_host *host, u32 ocr,
struct mmc_card *oldcard)
{
struct mmc_card *card;
int err;
u32 cid[4];
unsigned int max_dtr;
BUG_ON(!host);
WARN_ON(!host->claimed);
/*
* Since we're changing the OCR value, we seem to
* need to tell some cards to go back to the idle
* state. We wait 1ms to give cards time to
* respond.
*/
mmc_go_idle(host); /* 进入空闲模式 */
/* The extra bit indicates that we support high capacity */
err = mmc_send_op_cond(host, ocr | (1 << 30), NULL);
if (err)
goto err;
/*
* For SPI, enable CRC as appropriate.
*/
if (mmc_host_is_spi(host)) {
err = mmc_spi_set_crc(host, use_spi_crc);
if (err)
goto err;
}
/*
* Fetch CID from card.
*/
if (mmc_host_is_spi(host))
err = mmc_send_cid(host, cid);
else
err = mmc_all_send_cid(host, cid);
if (err)
goto err;
if (oldcard) {
if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
err = -ENOENT;
goto err;
}
card = oldcard;
} else {
/*
* Allocate card structure.
*/
card = mmc_alloc_card(host, &mmc_type); /* */
if (IS_ERR(card)) {
err = PTR_ERR(card);
goto err;
}
card->type = MMC_TYPE_MMC;
card->rca = 1;
memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
}
/*
* For native busses: set card RCA and quit open drain mode.
*/
if (!mmc_host_is_spi(host)) {
err = mmc_set_relative_addr(card);
if (err)
goto free_card;
mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
}
if (!oldcard) {
/*
* Fetch CSD from card.
*/
err = mmc_send_csd(card, card->raw_csd);
if (err)
goto free_card;
err = mmc_decode_csd(card);
if (err)
goto free_card;
err = mmc_decode_cid(card);
if (err)
goto free_card;
}
/*
* Select card, as all following commands rely on that.
*/
if (!mmc_host_is_spi(host)) {
err = mmc_select_card(card);
if (err)
goto free_card;
}
if (!oldcard) {
/*
* Fetch and process extended CSD.
*/
err = mmc_read_ext_csd(card);
if (err)
goto free_card;
}
/*
* Activate high speed (if supported)
*/
if ((card->ext_csd.hs_max_dtr != 0) &&
(host->caps & MMC_CAP_MMC_HIGHSPEED)) {
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HS_TIMING, 1);
if (err)
goto free_card;
mmc_card_set_highspeed(card);
mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
}
/*
* Compute bus speed.
*/
max_dtr = (unsigned int)-1;
if (mmc_card_highspeed(card)) {
if (max_dtr > card->ext_csd.hs_max_dtr)
max_dtr = card->ext_csd.hs_max_dtr;
} else if (max_dtr > card->csd.max_dtr) {
max_dtr = card->csd.max_dtr;
}
mmc_set_clock(host, max_dtr);
/*
* Activate wide bus (if supported).
*/
if ((card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
(host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA))) {
unsigned ext_csd_bit, bus_width;
if (host->caps & MMC_CAP_8_BIT_DATA) {
ext_csd_bit = EXT_CSD_BUS_WIDTH_8;
bus_width = MMC_BUS_WIDTH_8;
} else {
ext_csd_bit = EXT_CSD_BUS_WIDTH_4;
bus_width = MMC_BUS_WIDTH_4;
}
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_BUS_WIDTH, ext_csd_bit);
if (err)
goto free_card;
mmc_set_bus_width(card->host, bus_width);
}
if (!oldcard)
host->card = card;
return 0;
free_card:
if (!oldcard)
mmc_remove_card(card);
err:
return err;
}
/*
* Host is being removed. Free up the current card.
*/
/* 移除函数 */
static void mmc_remove(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(!host->card);
mmc_remove_card(host->card); /* 移除卡 */
host->card = NULL;
}
/*
* Card detection callback from host.
*/
/* 探测函数 */
static void mmc_detect(struct mmc_host *host)
{
int err;
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host); /* 声明一个主机控制器 */
/*
* Just check if our card has been removed.
*/
err = mmc_send_status(host->card, NULL); /* 发送卡的状态 */
mmc_release_host(host); /* 释放主机 */
if (err) {
mmc_remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_release_host(host);
}
}
#ifdef CONFIG_MMC_UNSAFE_RESUME
/*
* Suspend callback from host.
*/
/* 挂起函数 */
static void mmc_suspend(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host); /* 声明主机控制器 */
if (!mmc_host_is_spi(host))
mmc_deselect_cards(host);
host->card->state &= ~MMC_STATE_HIGHSPEED;
mmc_release_host(host);
}
/*
* Resume callback from host.
*
* This function tries to determine if the same card is still present
* and, if so, restore all state to it.
*/
/* 恢复函数 */
static void mmc_resume(struct mmc_host *host)
{
int err;
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host); /* 声明一个主机控制器 */
err = mmc_init_card(host, host->ocr, host->card); /* 初始化卡 */
mmc_release_host(host); /* 释放主机 */
if (err) {
mmc_remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_release_host(host);
}
}
#else
#define mmc_suspend NULL
#define mmc_resume NULL
#endif
static const struct mmc_bus_ops mmc_ops = { /* 总线操作函数 */
.remove = mmc_remove,
.detect = mmc_detect,
.suspend = mmc_suspend,
.resume = mmc_resume,
};
/*
* Starting point for MMC card init.
*/
/* */
int mmc_attach_mmc(struct mmc_host *host, u32 ocr)
{
int err;
BUG_ON(!host);
WARN_ON(!host->claimed);
mmc_attach_bus(host, &mmc_ops); /* 将主机和总线操作函数绑定 */
/*
* We need to get OCR a different way for SPI.
*/
if (mmc_host_is_spi(host)) {
err = mmc_spi_read_ocr(host, 1, &ocr);
if (err)
goto err;
}
/*
* Sanity check the voltages that the card claims to
* support.
*/
if (ocr & 0x7F) {
printk(KERN_WARNING "%s: card claims to support voltages "
"below the defined range. These will be ignored.\n",
mmc_hostname(host));
ocr &= ~0x7F;
}
host->ocr = mmc_select_voltage(host, ocr); /* 选择电压 */
/*
* Can we support the voltage of the card?
*/
if (!host->ocr) {
err = -EINVAL;
goto err;
}
/*
* Detect and init the card.
*/
err = mmc_init_card(host, host->ocr, NULL); /* 初始化卡 */
if (err)
goto err;
mmc_release_host(host); /* 释放主机 */
err = mmc_add_card(host->card); /* 添加卡 */
if (err)
goto remove_card;
return 0;
remove_card:
mmc_remove_card(host->card);
host->card = NULL;
mmc_claim_host(host);
err:
mmc_detach_bus(host);
mmc_release_host(host);
printk(KERN_ERR "%s: error %d whilst initialising MMC card\n",
mmc_hostname(host), err);
return err;
}
/*************************************************************************************************************************************/
/* mmc_ops.c */
/*
* linux/drivers/mmc/core/mmc_ops.h
*
* Copyright 2006-2007 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*/
#include <linux/types.h>
#include <linux/scatterlist.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/mmc.h>
#include "core.h"
#include "mmc_ops.h"
/* mmc操作函数集 */
/* 选中卡 */
static int _mmc_select_card(struct mmc_host *host, struct mmc_card *card)
{
int err;
struct mmc_command cmd;
BUG_ON(!host);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SELECT_CARD;
if (card) {
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
} else {
cmd.arg = 0;
cmd.flags = MMC_RSP_NONE | MMC_CMD_AC;
}
err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
if (err)
return err;
return 0;
}
/*选中卡 */
int mmc_select_card(struct mmc_card *card)
{
BUG_ON(!card);
return _mmc_select_card(card->host, card);
}
/* 取消选中 */
int mmc_deselect_cards(struct mmc_host *host)
{
return _mmc_select_card(host, NULL);
}
/* 进入空闲模式 */
int mmc_go_idle(struct mmc_host *host)
{
int err;
struct mmc_command cmd;
/*
* Non-SPI hosts need to prevent chipselect going active during
* GO_IDLE; that would put chips into SPI mode. Remind them of
* that in case of hardware that won't pull up DAT3/nCS otherwise.
*
* SPI hosts ignore ios.chip_select; it's managed according to
* rules that must accomodate non-MMC slaves which this layer
* won't even know about.
*/
if (!mmc_host_is_spi(host)) {
mmc_set_chip_select(host, MMC_CS_HIGH);
mmc_delay(1);
}
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_GO_IDLE_STATE;
cmd.arg = 0;
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_NONE | MMC_CMD_BC;
err = mmc_wait_for_cmd(host, &cmd, 0);
mmc_delay(1);
if (!mmc_host_is_spi(host)) {
mmc_set_chip_select(host, MMC_CS_DONTCARE);
mmc_delay(1);
}
host->use_spi_crc = 0;
return err;
}
int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
{
struct mmc_command cmd;
int i, err = 0;
BUG_ON(!host);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SEND_OP_COND;
cmd.arg = mmc_host_is_spi(host) ? 0 : ocr;
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R3 | MMC_CMD_BCR;
for (i = 100; i; i--) {
err = mmc_wait_for_cmd(host, &cmd, 0);
if (err)
break;
/* if we're just probing, do a single pass */
if (ocr == 0)
break;
/* otherwise wait until reset completes */
if (mmc_host_is_spi(host)) {
if (!(cmd.resp[0] & R1_SPI_IDLE))
break;
} else {
if (cmd.resp[0] & MMC_CARD_BUSY)
break;
}
err = -ETIMEDOUT;
mmc_delay(10);
}
if (rocr && !mmc_host_is_spi(host))
*rocr = cmd.resp[0];
return err;
}
int mmc_all_send_cid(struct mmc_host *host, u32 *cid)
{
int err;
struct mmc_command cmd;
BUG_ON(!host);
BUG_ON(!cid);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_ALL_SEND_CID;
cmd.arg = 0;
cmd.flags = MMC_RSP_R2 | MMC_CMD_BCR;
err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES); /* 等待命令发送完成 */
if (err)
return err;
memcpy(cid, cmd.resp, sizeof(u32) * 4);
return 0;
}
/* 设置相对地址 */
int mmc_set_relative_addr(struct mmc_card *card)
{
int err;
struct mmc_command cmd;
BUG_ON(!card);
BUG_ON(!card->host);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SET_RELATIVE_ADDR;
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
if (err)
return err;
return 0;
}
static int
mmc_send_cxd_native(struct mmc_host *host, u32 arg, u32 *cxd, int opcode)
{
int err;
struct mmc_command cmd;
BUG_ON(!host);
BUG_ON(!cxd);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = opcode;
cmd.arg = arg;
cmd.flags = MMC_RSP_R2 | MMC_CMD_AC;
err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
if (err)
return err;
memcpy(cxd, cmd.resp, sizeof(u32) * 4);
return 0;
}
static int
mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
u32 opcode, void *buf, unsigned len)
{
struct mmc_request mrq;
struct mmc_command cmd;
struct mmc_data data;
struct scatterlist sg;
void *data_buf;
/* dma onto stack is unsafe/nonportable, but callers to this
* routine normally provide temporary on-stack buffers ...
*/
data_buf = kmalloc(len, GFP_KERNEL);
if (data_buf == NULL)
return -ENOMEM;
memset(&mrq, 0, sizeof(struct mmc_request));
memset(&cmd, 0, sizeof(struct mmc_command));
memset(&data, 0, sizeof(struct mmc_data));
mrq.cmd = &cmd;
mrq.data = &data;
cmd.opcode = opcode;
cmd.arg = 0;
/* NOTE HACK: the MMC_RSP_SPI_R1 is always correct here, but we
* rely on callers to never use this with "native" calls for reading
* CSD or CID. Native versions of those commands use the R2 type,
* not R1 plus a data block.
*/
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
data.blksz = len;
data.blocks = 1;
data.flags = MMC_DATA_READ;
data.sg = &sg;
data.sg_len = 1;
sg_init_one(&sg, data_buf, len);
if (opcode == MMC_SEND_CSD || opcode == MMC_SEND_CID) {
/*
* The spec states that CSR and CID accesses have a timeout
* of 64 clock cycles.
*/
data.timeout_ns = 0;
data.timeout_clks = 64;
} else
mmc_set_data_timeout(&data, card);
mmc_wait_for_req(host, &mrq);
memcpy(buf, data_buf, len);
kfree(data_buf);
if (cmd.error)
return cmd.error;
if (data.error)
return data.error;
return 0;
}
int mmc_send_csd(struct mmc_card *card, u32 *csd)
{
int ret, i;
if (!mmc_host_is_spi(card->host))
return mmc_send_cxd_native(card->host, card->rca << 16,
csd, MMC_SEND_CSD);
ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd, 16);
if (ret)
return ret;
for (i = 0;i < 4;i++)
csd[i] = be32_to_cpu(csd[i]);
return 0;
}
int mmc_send_cid(struct mmc_host *host, u32 *cid)
{
int ret, i;
if (!mmc_host_is_spi(host)) {
if (!host->card)
return -EINVAL;
return mmc_send_cxd_native(host, host->card->rca << 16,
cid, MMC_SEND_CID);
}
ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid, 16);
if (ret)
return ret;
for (i = 0;i < 4;i++)
cid[i] = be32_to_cpu(cid[i]);
return 0;
}
int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd)
{
return mmc_send_cxd_data(card, card->host, MMC_SEND_EXT_CSD,
ext_csd, 512);
}
int mmc_spi_read_ocr(struct mmc_host *host, int highcap, u32 *ocrp)
{
struct mmc_command cmd;
int err;
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SPI_READ_OCR;
cmd.arg = highcap ? (1 << 30) : 0;
cmd.flags = MMC_RSP_SPI_R3;
err = mmc_wait_for_cmd(host, &cmd, 0);
*ocrp = cmd.resp[1];
return err;
}
int mmc_spi_set_crc(struct mmc_host *host, int use_crc)
{
struct mmc_command cmd;
int err;
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SPI_CRC_ON_OFF;
cmd.flags = MMC_RSP_SPI_R1;
cmd.arg = use_crc;
err = mmc_wait_for_cmd(host, &cmd, 0);
if (!err)
host->use_spi_crc = use_crc;
return err;
}
int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value)
{
int err;
struct mmc_command cmd;
BUG_ON(!card);
BUG_ON(!card->host);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SWITCH;
cmd.arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
(index << 16) |
(value << 8) |
set;
cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
if (err)
return err;
return 0;
}
/* 发送卡的状态 */
int mmc_send_status(struct mmc_card *card, u32 *status)
{
int err;
struct mmc_command cmd;
BUG_ON(!card);
BUG_ON(!card->host);
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SEND_STATUS;
if (!mmc_host_is_spi(card->host))
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES); /* 发送命令并等待它完成 */
if (err)
return err;
/* NOTE: callers are required to understand the difference
* between "native" and SPI format status words!
*/
if (status)
*status = cmd.resp[0];
return 0;
}
/*************************************************************************************************************************************/
/* sd.c */
/*
* linux/drivers/mmc/core/sd.c
*
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
* Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sd.h>
#include "core.h"
#include "bus.h"
#include "mmc_ops.h"
#include "sd_ops.h"
static const unsigned int tran_exp[] = {
10000, 100000, 1000000, 10000000,
0, 0, 0, 0
};
static const unsigned char tran_mant[] = {
0, 10, 12, 13, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
static const unsigned int tacc_exp[] = {
1, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
};
static const unsigned int tacc_mant[] = {
0, 10, 12, 13, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
#define UNSTUFF_BITS(resp,start,size) \
({ \
const int __size = size; \
const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
const int __off = 3 - ((start) / 32); \
const int __shft = (start) & 31; \
u32 __res; \
\
__res = resp[__off] >> __shft; \
if (__size + __shft > 32) \
__res |= resp[__off-1] << ((32 - __shft) % 32); \
__res & __mask; \
})
/*
* Given the decoded CSD structure, decode the raw CID to our CID structure.
*/
/* 解码CID寄存器 */
static void mmc_decode_cid(struct mmc_card *card)
{
u32 *resp = card->raw_cid;
memset(&card->cid, 0, sizeof(struct mmc_cid));
/*
* SD doesn't currently have a version field so we will
* have to assume we can parse this.
*/
card->cid.manfid = UNSTUFF_BITS(resp, 120, 8);
card->cid.oemid = UNSTUFF_BITS(resp, 104, 16);
card->cid.prod_name[0] = UNSTUFF_BITS(resp, 96, 8);
card->cid.prod_name[1] = UNSTUFF_BITS(resp, 88, 8);
card->cid.prod_name[2] = UNSTUFF_BITS(resp, 80, 8);
card->cid.prod_name[3] = UNSTUFF_BITS(resp, 72, 8);
card->cid.prod_name[4] = UNSTUFF_BITS(resp, 64, 8);
card->cid.hwrev = UNSTUFF_BITS(resp, 60, 4);
card->cid.fwrev = UNSTUFF_BITS(resp, 56, 4);
card->cid.serial = UNSTUFF_BITS(resp, 24, 32);
card->cid.year = UNSTUFF_BITS(resp, 12, 8);
card->cid.month = UNSTUFF_BITS(resp, 8, 4);
card->cid.year += 2000; /* SD cards year offset */
}
/*
* Given a 128-bit response, decode to our card CSD structure.
*/
/* 解码SCD寄存器 */
static int mmc_decode_csd(struct mmc_card *card)
{
struct mmc_csd *csd = &card->csd;
unsigned int e, m, csd_struct;
u32 *resp = card->raw_csd;
csd_struct = UNSTUFF_BITS(resp, 126, 2);
switch (csd_struct) {
case 0:
m = UNSTUFF_BITS(resp, 115, 4);
e = UNSTUFF_BITS(resp, 112, 3);
csd->tacc_ns = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
csd->tacc_clks = UNSTUFF_BITS(resp, 104, 8) * 100;
m = UNSTUFF_BITS(resp, 99, 4);
e = UNSTUFF_BITS(resp, 96, 3);
csd->max_dtr = tran_exp[e] * tran_mant[m];
csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);
e = UNSTUFF_BITS(resp, 47, 3);
m = UNSTUFF_BITS(resp, 62, 12);
csd->capacity = (1 + m) << (e + 2);
csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
break;
case 1:
/*
* This is a block-addressed SDHC card. Most
* interesting fields are unused and have fixed
* values. To avoid getting tripped by buggy cards,
* we assume those fixed values ourselves.
*/
mmc_card_set_blockaddr(card);
csd->tacc_ns = 0; /* Unused */
csd->tacc_clks = 0; /* Unused */
m = UNSTUFF_BITS(resp, 99, 4);
e = UNSTUFF_BITS(resp, 96, 3);
csd->max_dtr = tran_exp[e] * tran_mant[m];
csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);
m = UNSTUFF_BITS(resp, 48, 22);
csd->capacity = (1 + m) << 10;
csd->read_blkbits = 9;
csd->read_partial = 0;
csd->write_misalign = 0;
csd->read_misalign = 0;
csd->r2w_factor = 4; /* Unused */
csd->write_blkbits = 9;
csd->write_partial = 0;
break;
default:
printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
mmc_hostname(card->host), csd_struct);
return -EINVAL;
}
return 0;
}
/*
* Given a 64-bit response, decode to our card SCR structure.
*/
/* 解码SCR寄存器 */
static int mmc_decode_scr(struct mmc_card *card)
{
struct sd_scr *scr = &card->scr;
unsigned int scr_struct;
u32 resp[4];
resp[3] = card->raw_scr[1];
resp[2] = card->raw_scr[0];
scr_struct = UNSTUFF_BITS(resp, 60, 4);
if (scr_struct != 0) {
printk(KERN_ERR "%s: unrecognised SCR structure version %d\n",
mmc_hostname(card->host), scr_struct);
return -EINVAL;
}
scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
return 0;
}
/*
* Fetches and decodes switch information
*/
/* 获取总线宽度 */
static int mmc_read_switch(struct mmc_card *card)
{
int err;
u8 *status;
if (card->scr.sda_vsn < SCR_SPEC_VER_1)
return 0;
if (!(card->csd.cmdclass & CCC_SWITCH)) {
printk(KERN_WARNING "%s: card lacks mandatory switch "
"function, performance might suffer.\n",
mmc_hostname(card->host));
return 0;
}
err = -EIO;
status = kmalloc(64, GFP_KERNEL);
if (!status) {
printk(KERN_ERR "%s: could not allocate a buffer for "
"switch capabilities.\n", mmc_hostname(card->host));
return -ENOMEM;
}
err = mmc_sd_switch(card, 0, 0, 1, status);
if (err) {
/*
* We all hosts that cannot perform the command
* to fail more gracefully
*/
if (err != -EINVAL)
goto out;
printk(KERN_WARNING "%s: problem reading switch "
"capabilities, performance might suffer.\n",
mmc_hostname(card->host));
err = 0;
goto out;
}
if (status[13] & 0x02)
card->sw_caps.hs_max_dtr = 50000000;
out:
kfree(status);
return err;
}
/*
* Test if the card supports high-speed mode and, if so, switch to it.
*/
/* 测试卡是否支持高度模式，如果支持则切换到高速模式 */
static int mmc_switch_hs(struct mmc_card *card)
{
int err;
u8 *status;
if (card->scr.sda_vsn < SCR_SPEC_VER_1)
return 0;
if (!(card->csd.cmdclass & CCC_SWITCH))
return 0;
if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
return 0;
if (card->sw_caps.hs_max_dtr == 0)
return 0;
err = -EIO;
status = kmalloc(64, GFP_KERNEL);
if (!status) {
printk(KERN_ERR "%s: could not allocate a buffer for "
"switch capabilities.\n", mmc_hostname(card->host));
return -ENOMEM;
}
err = mmc_sd_switch(card, 1, 0, 1, status);
if (err)
goto out;
if ((status[16] & 0xF) != 1) {
printk(KERN_WARNING "%s: Problem switching card "
"into high-speed mode!\n",
mmc_hostname(card->host));
} else {
mmc_card_set_highspeed(card);
mmc_set_timing(card->host, MMC_TIMING_SD_HS);
}
out:
kfree(status);
return err;
}
MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
card->raw_cid[2], card->raw_cid[3]);
MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
card->raw_csd[2], card->raw_csd[3]);
MMC_DEV_ATTR(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
static struct attribute *sd_std_attrs[] = {
&dev_attr_cid.attr,
&dev_attr_csd.attr,
&dev_attr_scr.attr,
&dev_attr_date.attr,
&dev_attr_fwrev.attr,
&dev_attr_hwrev.attr,
&dev_attr_manfid.attr,
&dev_attr_name.attr,
&dev_attr_oemid.attr,
&dev_attr_serial.attr,
NULL,
};
static struct attribute_group sd_std_attr_group = {
.attrs = sd_std_attrs,
};
static struct attribute_group *sd_attr_groups[] = {
&sd_std_attr_group,
NULL,
};
static struct device_type sd_type = {
.groups = sd_attr_groups,
};
/*
* Handle the detection and initialisation of a card.
*
* In the case of a resume, "oldcard" will contain the card
* we're trying to reinitialise.
*/
/* 探测并初始化SD卡 */
static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
struct mmc_card *oldcard)
{
struct mmc_card *card;
int err;
u32 cid[4];
unsigned int max_dtr;
BUG_ON(!host);
WARN_ON(!host->claimed);
/*
* Since we're changing the OCR value, we seem to
* need to tell some cards to go back to the idle
* state. We wait 1ms to give cards time to
* respond.
*/
mmc_go_idle(host); /* 进入空闲模式 */
/*
* If SD_SEND_IF_COND indicates an SD 2.0
* compliant card and we should set bit 30
* of the ocr to indicate that we can handle
* block-addressed SDHC cards.
*/
err = mmc_send_if_cond(host, ocr);
if (!err)
ocr |= 1 << 30;
err = mmc_send_app_op_cond(host, ocr, NULL);
if (err)
goto err;
/*
* Fetch CID from card.
*/
if (mmc_host_is_spi(host))
err = mmc_send_cid(host, cid);
else
err = mmc_all_send_cid(host, cid); /* 读取存储卡的CID寄存器 */
if (err)
goto err;
if (oldcard) {
if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
err = -ENOENT;
goto err;
}
card = oldcard;
} else {
/*
* Allocate card structure.
*/
card = mmc_alloc_card(host, &sd_type);
if (IS_ERR(card)) {
err = PTR_ERR(card);
goto err;
}
card->type = MMC_TYPE_SD;
memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
}
/*
* For native busses: get card RCA and quit open drain mode.
*/
if (!mmc_host_is_spi(host)) {
err = mmc_send_relative_addr(host, &card->rca);
if (err)
goto free_card;
mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
}
if (!oldcard) {
/*
* Fetch CSD from card.
*/
err = mmc_send_csd(card, card->raw_csd);
if (err)
goto free_card;
err = mmc_decode_csd(card);
if (err)
goto free_card;
mmc_decode_cid(card);
}
/*
* Select card, as all following commands rely on that.
*/
if (!mmc_host_is_spi(host)) {
err = mmc_select_card(card);
if (err)
goto free_card;
}
if (!oldcard) {
/*
* Fetch SCR from card.
*/
err = mmc_app_send_scr(card, card->raw_scr);
if (err)
goto free_card;
err = mmc_decode_scr(card);
if (err < 0)
goto free_card;
/*
* Fetch switch information from card.
*/
err = mmc_read_switch(card);
if (err)
goto free_card;
}
/*
* For SPI, enable CRC as appropriate.
* This CRC enable is located AFTER the reading of the
* card registers because some SDHC cards are not able
* to provide valid CRCs for non-512-byte blocks.
*/
if (mmc_host_is_spi(host)) {
err = mmc_spi_set_crc(host, use_spi_crc);
if (err)
goto free_card;
}
/*
* Attempt to change to high-speed (if supported)
*/
err = mmc_switch_hs(card);
if (err)
goto free_card;
/*
* Compute bus speed.
*/
max_dtr = (unsigned int)-1;
if (mmc_card_highspeed(card)) {
if (max_dtr > card->sw_caps.hs_max_dtr)
max_dtr = card->sw_caps.hs_max_dtr;
} else if (max_dtr > card->csd.max_dtr) {
max_dtr = card->csd.max_dtr;
}
mmc_set_clock(host, max_dtr);
/*
* Switch to wider bus (if supported).
*/
if ((host->caps & MMC_CAP_4_BIT_DATA) &&
(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
if (err)
goto free_card;
mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
}
/*
* Check if read-only switch is active.
*/
if (!oldcard) {
if (!host->ops->get_ro || host->ops->get_ro(host) < 0) {
printk(KERN_WARNING "%s: host does not "
"support reading read-only "
"switch. assuming write-enable.\n",
mmc_hostname(host));
} else {
if (host->ops->get_ro(host) > 0)
mmc_card_set_readonly(card);
}
}
if (!oldcard)
host->card = card;
return 0;
free_card:
if (!oldcard)
mmc_remove_card(card);
err:
return err;
}
/*
* Host is being removed. Free up the current card.
*/
/* 移除函数 */
static void mmc_sd_remove(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(!host->card);
mmc_remove_card(host->card); /* 移除卡 */
host->card = NULL;
}
/*
* Card detection callback from host.
*/
/* 探测函数 */
static void mmc_sd_detect(struct mmc_host *host)
{
int err;
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host);
/*
* Just check if our card has been removed.
*/
err = mmc_send_status(host->card, NULL);
mmc_release_host(host);
if (err) {
mmc_sd_remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_release_host(host);
}
}
#ifdef CONFIG_MMC_UNSAFE_RESUME
/*
* Suspend callback from host.
*/
/* 挂起函数 */
static void mmc_sd_suspend(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host);
if (!mmc_host_is_spi(host))
mmc_deselect_cards(host);
host->card->state &= ~MMC_STATE_HIGHSPEED;
mmc_release_host(host);
}
/*
* Resume callback from host.
*
* This function tries to determine if the same card is still present
* and, if so, restore all state to it.
*/
/* 恢复函数 */
static void mmc_sd_resume(struct mmc_host *host)
{
int err;
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host); /* 声明一个主机控制器 */
err = mmc_sd_init_card(host, host->ocr, host->card);/* 探测并初始化SD卡 */
mmc_release_host(host); /* 释放主机 */
if (err) {
mmc_sd_remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_release_host(host);
}
}
#else
#define mmc_sd_suspend NULL
#define mmc_sd_resume NULL
#endif
static const struct mmc_bus_ops mmc_sd_ops = { /* SD总线操作函数 */
.remove = mmc_sd_remove,
.detect = mmc_sd_detect,
.suspend = mmc_sd_suspend,
.resume = mmc_sd_resume,
};
/*
* Starting point for SD card init.
*/
/* 依附一个SD卡 */
int mmc_attach_sd(struct mmc_host *host, u32 ocr)
{
int err;
BUG_ON(!host);
WARN_ON(!host->claimed);
mmc_attach_bus(host, &mmc_sd_ops); /* 将主机和总线绑定 */
/*
* We need to get OCR a different way for SPI.
*/
if (mmc_host_is_spi(host)) {
mmc_go_idle(host);
err = mmc_spi_read_ocr(host, 0, &ocr);
if (err)
goto err;
}
/*
* Sanity check the voltages that the card claims to
* support.
*/
if (ocr & 0x7F) {
printk(KERN_WARNING "%s: card claims to support voltages "
"below the defined range. These will be ignored.\n",
mmc_hostname(host));
ocr &= ~0x7F;
}
if (ocr & MMC_VDD_165_195) {
printk(KERN_WARNING "%s: SD card claims to support the "
"incompletely defined 'low voltage range'. This "
"will be ignored.\n", mmc_hostname(host));
ocr &= ~MMC_VDD_165_195;
}
host->ocr = mmc_select_voltage(host, ocr); /* 选择工作电压 */
/*
* Can we support the voltage(s) of the card(s)?
*/
if (!host->ocr) {
err = -EINVAL;
goto err;
}
/*
* Detect and init the card.
*/
err = mmc_sd_init_card(host, host->ocr, NULL); /* 探测并初始化SD卡 */
if (err)
goto err;
mmc_release_host(host); /* 释放主机控制器 */
err = mmc_add_card(host->card); /* 添加一个SD卡 */
if (err)
goto remove_card;
return 0;
remove_card:
mmc_remove_card(host->card);
host->card = NULL;
mmc_claim_host(host);
err:
mmc_detach_bus(host);
mmc_release_host(host);
printk(KERN_ERR "%s: error %d whilst initialising SD card\n",
mmc_hostname(host), err);
return err;
}
/*************************************************************************************************************************************/
/* sdio_bus.c */
/*
* linux/drivers/mmc/core/sdio_bus.c
*
* Copyright 2007 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* SDIO function driver model
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/mmc/card.h>
#include <linux/mmc/sdio_func.h>
#include "sdio_cis.h"
#include "sdio_bus.h"
#define dev_to_sdio_func(d) container_of(d, struct sdio_func, dev)
#define to_sdio_driver(d) container_of(d, struct sdio_driver, drv)
/* show configuration fields */
#define sdio_config_attr(field, format_string) \
static ssize_t \
field##_show(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
struct sdio_func *func; \
\
func = dev_to_sdio_func (dev); \
return sprintf (buf, format_string, func->field); \
}
sdio_config_attr(class, "0x%02x\n");
sdio_config_attr(vendor, "0x%04x\n");
sdio_config_attr(device, "0x%04x\n");
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct sdio_func *func = dev_to_sdio_func (dev);
return sprintf(buf, "sdio:c%02Xv%04Xd%04X\n",
func->class, func->vendor, func->device);
}
static struct device_attribute sdio_dev_attrs[] = {
__ATTR_RO(class),
__ATTR_RO(vendor),
__ATTR_RO(device),
__ATTR_RO(modalias),
__ATTR_NULL,
};
static const struct sdio_device_id *sdio_match_one(struct sdio_func *func,
const struct sdio_device_id *id)
{
if (id->class != (__u8)SDIO_ANY_ID && id->class != func->class)
return NULL;
if (id->vendor != (__u16)SDIO_ANY_ID && id->vendor != func->vendor)
return NULL;
if (id->device != (__u16)SDIO_ANY_ID && id->device != func->device)
return NULL;
return id;
}
static const struct sdio_device_id *sdio_match_device(struct sdio_func *func,
struct sdio_driver *sdrv)
{
const struct sdio_device_id *ids;
ids = sdrv->id_table;
if (ids) {
while (ids->class || ids->vendor || ids->device) {
if (sdio_match_one(func, ids))
return ids;
ids++;
}
}
return NULL;
}
static int sdio_bus_match(struct device *dev, struct device_driver *drv)
{
struct sdio_func *func = dev_to_sdio_func(dev);
struct sdio_driver *sdrv = to_sdio_driver(drv);
if (sdio_match_device(func, sdrv))
return 1;
return 0;
}
static int
sdio_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct sdio_func *func = dev_to_sdio_func(dev);
if (add_uevent_var(env,
"SDIO_CLASS=%02X", func->class))
return -ENOMEM;
if (add_uevent_var(env,
"SDIO_ID=%04X:%04X", func->vendor, func->device))
return -ENOMEM;
if (add_uevent_var(env,
"MODALIAS=sdio:c%02Xv%04Xd%04X",
func->class, func->vendor, func->device))
return -ENOMEM;
return 0;
}
static int sdio_bus_probe(struct device *dev)
{
struct sdio_driver *drv = to_sdio_driver(dev->driver);
struct sdio_func *func = dev_to_sdio_func(dev);
const struct sdio_device_id *id;
int ret;
id = sdio_match_device(func, drv);
if (!id)
return -ENODEV;
/* Set the default block size so the driver is sure it's something
* sensible. */
sdio_claim_host(func);
ret = sdio_set_block_size(func, 0);
sdio_release_host(func);
if (ret)
return ret;
return drv->probe(func, id);
}
static int sdio_bus_remove(struct device *dev)
{
struct sdio_driver *drv = to_sdio_driver(dev->driver);
struct sdio_func *func = dev_to_sdio_func(dev);
drv->remove(func);
if (func->irq_handler) {
printk(KERN_WARNING "WARNING: driver %s did not remove "
"its interrupt handler!\n", drv->name);
sdio_claim_host(func);
sdio_release_irq(func);
sdio_release_host(func);
}
return 0;
}
static struct bus_type sdio_bus_type = { /*定义总线类型 */
.name = "sdio",
.dev_attrs = sdio_dev_attrs,
.match = sdio_bus_match,
.uevent = sdio_bus_uevent,
.probe = sdio_bus_probe,
.remove = sdio_bus_remove,
};
/* 注册SDIO总线 */
int sdio_register_bus(void)
{
return bus_register(&sdio_bus_type); /* 注册总线 */
}
/* 注销SDIO总线 */
void sdio_unregister_bus(void)
{
bus_unregister(&sdio_bus_type);
}
/**
* sdio_register_driver - register a function driver
* @drv: SDIO function driver
*/
int sdio_register_driver(struct sdio_driver *drv) /* 注册SDIO总线驱动 */
{
drv->drv.name = drv->name;
drv->drv.bus = &sdio_bus_type;
return driver_register(&drv->drv);
}
EXPORT_SYMBOL_GPL(sdio_register_driver);
/**
* sdio_unregister_driver - unregister a function driver
* @drv: SDIO function driver
*/
void sdio_unregister_driver(struct sdio_driver *drv) /* 注销SDIO总线驱动 */
{
drv->drv.bus = &sdio_bus_type;
driver_unregister(&drv->drv);
}
EXPORT_SYMBOL_GPL(sdio_unregister_driver);
static void sdio_release_func(struct device *dev)
{
struct sdio_func *func = dev_to_sdio_func(dev);
sdio_free_func_cis(func);
if (func->info)
kfree(func->info);
kfree(func);
}
/*
* Allocate and initialise a new SDIO function structure.
*/
struct sdio_func *sdio_alloc_func(struct mmc_card *card)
{
struct sdio_func *func;
func = kzalloc(sizeof(struct sdio_func), GFP_KERNEL);
if (!func)
return ERR_PTR(-ENOMEM);
func->card = card;
device_initialize(&func->dev);
func->dev.parent = &card->dev;
func->dev.bus = &sdio_bus_type;
func->dev.release = sdio_release_func;
return func;
}
/*
* Register a new SDIO function with the driver model.
*/
int sdio_add_func(struct sdio_func *func)
{
int ret;
dev_set_name(&func->dev, "%s:%d", mmc_card_id(func->card), func->num);
ret = device_add(&func->dev);
if (ret == 0)
sdio_func_set_present(func);
return ret;
}
/*
* Unregister a SDIO function with the driver model, and
* (eventually) free it.
*/
void sdio_remove_func(struct sdio_func *func)
{
if (sdio_func_present(func))
device_del(&func->dev);
put_device(&func->dev);
}
/*************************************************************************************************************************************/
/* sdio_irq.c */
/*
* linux/drivers/mmc/core/sdio_irq.c
*
* Author: Nicolas Pitre
* Created: June 18, 2007
* Copyright: MontaVista Software Inc.
*
* Copyright 2008 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/mmc/core.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/sdio_func.h>
#include "sdio_ops.h"
/* 处理SDIO挂起中断 */
static int process_sdio_pending_irqs(struct mmc_card *card)
{
int i, ret, count;
unsigned char pending;
ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
if (ret) {
printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
mmc_card_id(card), ret);
return ret;
}
count = 0;
for (i = 1; i <= 7; i++) {
if (pending & (1 << i)) {
struct sdio_func *func = card->sdio_func[i - 1];
if (!func) {
printk(KERN_WARNING "%s: pending IRQ for "
"non-existant function\n",
mmc_card_id(card));
ret = -EINVAL;
} else if (func->irq_handler) {
func->irq_handler(func);
count++;
} else {
printk(KERN_WARNING "%s: pending IRQ with no handler\n",
sdio_func_id(func));
ret = -EINVAL;
}
}
}
if (count)
return count;
return ret;
}
/* SDIO中断处理线程 */
static int sdio_irq_thread(void *_host)
{
struct mmc_host *host = _host;
struct sched_param param = { .sched_priority = 1 };
unsigned long period, idle_period;
int ret;
sched_setscheduler(current, SCHED_FIFO, ¶m);
/*
* We want to allow for SDIO cards to work even on non SDIO
* aware hosts. One thing that non SDIO host cannot do is
* asynchronous notification of pending SDIO card interrupts
* hence we poll for them in that case.
*/
idle_period = msecs_to_jiffies(10);
period = (host->caps & MMC_CAP_SDIO_IRQ) ?
MAX_SCHEDULE_TIMEOUT : idle_period;
pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
mmc_hostname(host), period);
do {
/*
* We claim the host here on drivers behalf for a couple
* reasons:
*
* 1) it is already needed to retrieve the CCCR_INTx;
* 2) we want the driver(s) to clear the IRQ condition ASAP;
* 3) we need to control the abort condition locally.
*
* Just like traditional hard IRQ handlers, we expect SDIO
* IRQ handlers to be quick and to the point, so that the
* holding of the host lock does not cover too much work
* that doesn't require that lock to be held.
*/
ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
if (ret)
break;
ret = process_sdio_pending_irqs(host->card);
mmc_release_host(host);
/*
* Give other threads a chance to run in the presence of
* errors.
*/
if (ret < 0) {
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop())
schedule_timeout(HZ);
set_current_state(TASK_RUNNING);
}
/*
* Adaptive polling frequency based on the assumption
* that an interrupt will be closely followed by more.
* This has a substantial benefit for network devices.
*/
if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
if (ret > 0)
period /= 2;
else {
period++;
if (period > idle_period)
period = idle_period;
}
}
set_current_state(TASK_INTERRUPTIBLE);
if (host->caps & MMC_CAP_SDIO_IRQ)
host->ops->enable_sdio_irq(host, 1);
if (!kthread_should_stop())
schedule_timeout(period);
set_current_state(TASK_RUNNING);
} while (!kthread_should_stop());
if (host->caps & MMC_CAP_SDIO_IRQ)
host->ops->enable_sdio_irq(host, 0);
pr_debug("%s: IRQ thread exiting with code %d\n",
mmc_hostname(host), ret);
return ret;
}
static int sdio_card_irq_get(struct mmc_card *card)
{
struct mmc_host *host = card->host;
WARN_ON(!host->claimed);
if (!host->sdio_irqs++) {
atomic_set(&host->sdio_irq_thread_abort, 0);
host->sdio_irq_thread =
kthread_run(sdio_irq_thread, host, "ksdioirqd/%s",
mmc_hostname(host));
if (IS_ERR(host->sdio_irq_thread)) {
int err = PTR_ERR(host->sdio_irq_thread);
host->sdio_irqs--;
return err;
}
}
return 0;
}
static int sdio_card_irq_put(struct mmc_card *card)
{
struct mmc_host *host = card->host;
WARN_ON(!host->claimed);
BUG_ON(host->sdio_irqs < 1);
if (!--host->sdio_irqs) {
atomic_set(&host->sdio_irq_thread_abort, 1);
kthread_stop(host->sdio_irq_thread);
}
return 0;
}
/**
* sdio_claim_irq - claim the IRQ for a SDIO function
* @func: SDIO function
* @handler: IRQ handler callback
*
* Claim and activate the IRQ for the given SDIO function. The provided
* handler will be called when that IRQ is asserted. The host is always
* claimed already when the handler is called so the handler must not
* call sdio_claim_host() nor sdio_release_host().
*/
/* 声明中断 */
int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
{
int ret;
unsigned char reg;
BUG_ON(!func);
BUG_ON(!func->card);
pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
if (func->irq_handler) {
pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
return -EBUSY;
}
ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®);
if (ret)
return ret;
reg |= 1 << func->num;
reg |= 1; /* Master interrupt enable */
ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
if (ret)
return ret;
func->irq_handler = handler;
ret = sdio_card_irq_get(func->card);
if (ret)
func->irq_handler = NULL;
return ret;
}
EXPORT_SYMBOL_GPL(sdio_claim_irq);
/**
* sdio_release_irq - release the IRQ for a SDIO function
* @func: SDIO function
*
* Disable and release the IRQ for the given SDIO function.
*/
/* 释放中断 */
int sdio_release_irq(struct sdio_func *func)
{
int ret;
unsigned char reg;
BUG_ON(!func);
BUG_ON(!func->card);
pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
if (func->irq_handler) {
func->irq_handler = NULL;
sdio_card_irq_put(func->card);
}
ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®);
if (ret)
return ret;
reg &= ~(1 << func->num);
/* Disable master interrupt with the last function interrupt */
if (!(reg & 0xFE))
reg = 0;
ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
if (ret)
return ret;
return 0;
}
EXPORT_SYMBOL_GPL(sdio_release_irq);
