.相关函数

int request_firmware_nowait(

    struct module *module, bool uevent,

    const char *name,

    struct device *device,

    gfp_t gfp,

    void *context, /*驱动自己可以向回调函数传递一个参数，一般指向驱动设备结构体*/

    void (*cont)(const struct firmware *fw, void *context)) /*失败时传入的fw=NULL*/

int request_firmware(const struct firmware **firmware_p, const char *name, struct device *device)

void release_firmware(const struct firmware *fw)

request_firmware_nowait

    INIT_WORK(&fw_work->work, request_firmware_work_func); schedule_work(&fw_work->work); 这就是异步的实现方法，queue到内核线程中去执行

        fw_get_filesystem_firmware

            kernel_read_file_from_path

                file = filp_open(path, O_RDONLY, );

                kernel_read_file(file, buf, size, max_size, id);

/* direct firmware loading support */

static char fw_path_para[];

static const char * const fw_path[] = { /* 固件查找路径 */

    fw_path_para,                       /* 模块参数，可作为启动参数 */

    "/lib/firmware/updates/" UTS_RELEASE,

    "/lib/firmware/updates",

    "/lib/firmware/" UTS_RELEASE,

    "/lib/firmware"

};

module_param_string(path, fw_path_para, sizeof(fw_path_para), );  /*这个还做为模块参数供用户配置*/

MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");

struct firmware {

    size_t size;

    const u8 *data;        /*data里面存的直接是打卡固件里面的数据*/

    struct page **pages;

    /* firmware loader private fields */

    void *priv; /*_request_firmware_prepare中指向struct firmware_buf *buf， 若驱动App这里指定为null,内核分配的buff就存在这里*/

};

error = request_firmware_nowait(THIS_MODULE, true, "maxtouch.cfg", &client->dev, GFP_KERNEL, data, mxt_config_cb);

mxt_config_cb(const struct firmware *cfg, void *ctx)

{

    printk(KERN_INFO"sfl: size=%d, content=%s\n", cfg->size, buff);

}

# mkdir -p /lib/firmware/updates

# touch /lib/firmware/updates/maxtouch.cfg

# ehco abcdefghijklmnopqrst > /lib/firmware/updates/maxtouch.cfg

打印：

sfl: size=, content=abcdefghijklmnopqrst