设备驱动-memory-region和of_reserved_mem_device_init将设备与reserved mem关联

上一篇： RESERVEDMEM_OF_DECLARE 对 dts 中预留的内存进行匹配和初始化

https://www.cnblogs.com/zhangzhiwei122/p/16125744.html

 

另外，dts 中，通常使用 memory-region 将设备和 reserved memory 关联起来，如下：

 

 

 fb0 通过 memory-region 关联到  display_reserved 这块 reserved memory 上面；

 

of_reserved_mem_device_init

include/linux/of_reserved_mem.h 

传入参数 dev， 找到 dev 中 memory-region 对应的 reserved memory .然后调用 reserved_memory 对象的  ops->device_init( reserved_memory * rmem, device * dev );

  81static inline int of_reserved_mem_device_init(struct device *dev)
  82{
  83        return of_reserved_mem_device_init_by_idx(dev, dev->of_node, 0);
  84}

 

reserved memory 结构体中的ops 

include/linux/of_reserved_mem.h 

  11struct reserved_mem {
  12        const char                      *name;
  13        unsigned long                   fdt_node;
  14        unsigned long                   phandle;
  15        const struct reserved_mem_ops   *ops;
  16        phys_addr_t                     base;
  17        phys_addr_t                     size;
  18        void                            *priv;
  19};
  20
  21struct reserved_mem_ops {
  22        int     (*device_init)(struct reserved_mem *rmem,
  23                               struct device *dev);
  24        void    (*device_release)(struct reserved_mem *rmem,
  25                                  struct device *dev);
  26};

 

of_reserved_mem_device_init_by_idx 

从  of_reserved_mem_device_init 进入时，dev , dev_node, idx = 0 ;

 321int of_reserved_mem_device_init_by_idx(struct device *dev,
 322                                       struct device_node *np, int idx)
 323{
 324        struct rmem_assigned_device *rd;
 325        struct device_node *target;
 326        struct reserved_mem *rmem;
 327        int ret;
 328
 329        if (!np || !dev)
 330                return -EINVAL;
 331
 332        target = of_parse_phandle(np, "memory-region", idx);
 333        if (!target)
 334                return -ENODEV;
 335
 336        if (!of_device_is_available(target)) {
 337                of_node_put(target);
 338                return 0;
 339        }
 340
 341        rmem = __find_rmem(target);
 342        of_node_put(target);
 343
 344        if (!rmem || !rmem->ops || !rmem->ops->device_init)
 345                return -EINVAL;
 346
 347        rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL);
 348        if (!rd)
 349                return -ENOMEM;
 350
 351        ret = rmem->ops->device_init(rmem, dev);
 352        if (ret == 0) {
 353                rd->dev = dev;
 354                rd->rmem = rmem;
 355
 356                mutex_lock(&of_rmem_assigned_device_mutex);
 357                list_add(&rd->list, &of_rmem_assigned_device_list);
 358                mutex_unlock(&of_rmem_assigned_device_mutex);
 359
 360                dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
 361        } else {
 362                kfree(rd);
 363        }
 364
 365        return ret;
 366}
 367EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);

332 ~ 342 通过 memory-region 找对应的 reserved memory 

344 ~ 345 检查 有 rmem->ops   rmem->ops->device_init 函数 

 

351 调用  rmem->ops->device_init(rmem, dev) ; 

成功的话，就 将 建立的对象 reserved_memory_device  加入到  of_rmem_assigned_device_list 里面 ，记录 rmem 分配到 device 里面了。