dma 测试例子
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mman.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
#include <linux/version.h>
#include <linux/delay.h>
#include <mach/dma.h>
#include <linux/dmaengine.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/delay.h>
static int gMajor; /* major number of device */
static struct class *dma_tm_class;
u32 *wbuf, *wbuf2, *wbuf3;
u32 *rbuf, *rbuf2, *rbuf3;
u32 *rxbuf,*txbuf;
struct dma_chan *dma_m2m_chan_rx,*dma_m2m_chan_tx;
struct completion dma_m2m_ok;
struct scatterlist sg_rx[1],sg_tx[1],sg[3], sg2[3];
#define SDMA_BUF_SIZE 1024
static bool dma_m2m_filter(struct dma_chan *chan, void *param)
{
if (!imx_dma_is_general_purpose(chan))
{
printk("I #################\n");
return false;
}
chan->private = param;
return true;
}
static void dma_m2m_callback(void *data)
{
printk("in %s\n",__func__);
complete(&dma_m2m_ok);
return ;
}
static int imx_fpga_dma_init()
{
dma_cap_mask_t dma_m2m_mask;
struct imx_dma_data m2m_dma_data = {0};
struct dma_slave_config dma_m2m_config;
init_completion(&dma_m2m_ok);
dma_cap_zero(dma_m2m_mask);
dma_cap_set(DMA_SLAVE, dma_m2m_mask);
m2m_dma_data.peripheral_type = IMX_DMATYPE_EXT;
m2m_dma_data.priority = DMA_PRIO_HIGH;
dma_m2m_chan_rx = dma_request_channel(dma_m2m_mask, dma_m2m_filter, &m2m_dma_data);
dma_m2m_config.direction = DMA_FROM_DEVICE;
dma_m2m_config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
dma_m2m_config.src_addr =0x74000000;
dmaengine_slave_config(dma_m2m_chan_rx, &dma_m2m_config);
rxbuf=kzalloc(SDMA_BUF_SIZE, GFP_DMA);
/* tx*/
dma_m2m_chan_tx = dma_request_channel(dma_m2m_mask, dma_m2m_filter, &m2m_dma_data);
dma_m2m_config.direction = DMA_TO_DEVICE;
dma_m2m_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
dma_m2m_config.dst_addr =0x74000000;
dmaengine_slave_config(dma_m2m_chan_tx, &dma_m2m_config);
txbuf=kzalloc(SDMA_BUF_SIZE, GFP_DMA);
}
static int start_rx_dma()
{
int ret;
struct dma_async_tx_descriptor *desc;
sg_init_table(sg_rx, 1);
sg_set_buf(&sg_rx[0],rxbuf,SDMA_BUF_SIZE);
ret = dma_map_sg(NULL, sg_rx, 1, DMA_FROM_DEVICE);
if (ret == 0) {
pr_err("DMA mapping error for RX.\n");
return -EINVAL;
}
desc = dma_m2m_chan_rx->device->device_prep_slave_sg(dma_m2m_chan_rx,
sg_rx, 1, DMA_FROM_DEVICE, 0);
if (!desc) {
pr_err("We cannot prepare for the RX slave dma!\n");
return -EINVAL;
}
desc->callback = dma_m2m_callback;
dmaengine_submit(desc);
dmaengine_submit(desc);
dma_unmap_sg(NULL, sg_rx, 1, DMA_FROM_DEVICE);
return 0;
}
static int start_tx_dma()
{
int ret;
struct dma_async_tx_descriptor *desc;
memset(txbuf,0x33,SDMA_BUF_SIZE);
sg_init_table(sg_tx, 1);
sg_set_buf(&sg_tx[0],txbuf,SDMA_BUF_SIZE);
ret = dma_map_sg(NULL, sg_tx, 1, DMA_TO_DEVICE);
desc = dma_m2m_chan_tx->device->device_prep_slave_sg(dma_m2m_chan_tx,
sg_tx, 1, DMA_FROM_DEVICE, DMA_PREP_INTERRUPT| DMA_COMPL_SKIP_DEST_UNMAP);
if (!desc) {
pr_err("We cannot prepare for the tX slave dma!\n");
return -EINVAL;
}
desc->callback = dma_m2m_callback;
dmaengine_submit(desc);
dmaengine_submit(desc);
dma_unmap_sg(NULL, sg_tx, 1, DMA_TO_DEVICE);
return 0;
}
int sdma_open(struct inode * inode, struct file * filp)
{
imx_fpga_dma_init();
return 0;
}
int sdma_release(struct inode * inode, struct file * filp)
{
dma_release_channel(dma_m2m_chan_rx);
dma_m2m_chan_rx = NULL;
dma_release_channel(dma_m2m_chan_tx);
dma_m2m_chan_tx = NULL;
/* kfree(wbuf);
kfree(wbuf2);
kfree(wbuf3);
kfree(rbuf);
kfree(rbuf2);
kfree(rbuf3);*/
return 0;
}
ssize_t sdma_read (struct file *filp, char __user * buf, size_t count,
loff_t * offset)
{
//start_rx_dma();
return 0;
}
ssize_t sdma_write(struct file * filp, const char __user * buf, size_t count,
loff_t * offset)
{
start_tx_dma();
return 0;
}
struct file_operations dma_fops = {
open: sdma_open,
release: sdma_release,
read: sdma_read,
write: sdma_write,
};
int __init sdma_init_module(void)
{
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26))
struct device *temp_class;
#else
struct class_device *temp_class;
#endif
int error;
/* register a character device */
error = register_chrdev(0, "sdma_test", &dma_fops);
if (error < 0) {
printk("SDMA test driver can't get major number\n");
return error;
}
gMajor = error;
printk("SDMA test major number = %d\n",gMajor);
dma_tm_class = class_create(THIS_MODULE, "sdma_test");
if (IS_ERR(dma_tm_class)) {
printk(KERN_ERR "Error creating sdma test module class.\n");
unregister_chrdev(gMajor, "sdma_test");
return PTR_ERR(dma_tm_class);
}
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28))
temp_class = device_create(dma_tm_class, NULL,
MKDEV(gMajor, 0), NULL, "sdma_test");
#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26))
temp_class = device_create(dma_tm_class, NULL,
MKDEV(gMajor, 0), "sdma_test");
#else
temp_class = class_device_create(dma_tm_class, NULL,
MKDEV(gMajor, 0), NULL,
"sdma_test");
#endif
if (IS_ERR(temp_class)) {
printk(KERN_ERR "Error creating sdma test class device.\n");
class_destroy(dma_tm_class);
unregister_chrdev(gMajor, "sdma_test");
return -1;
}
printk("SDMA test Driver Module loaded\n");
return 0;
}
static void sdma_cleanup_module(void)
{
unregister_chrdev(gMajor, "sdma_test");
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26))
device_destroy(dma_tm_class, MKDEV(gMajor, 0));
#else
class_device_destroy(dma_tm_class, MKDEV(gMajor, 0));
#endif
class_destroy(dma_tm_class);
printk("SDMA test Driver Module Unloaded\n");
}
module_init(sdma_init_module);
module_exit(sdma_cleanup_module);
MODULE_AUTHOR("Freescale Semiconductor");
MODULE_DESCRIPTION("SDMA test driver");
MODULE_LICENSE("GPL");
