驱动开发笔记——platform_set_drvdata分析 （转）

函数static inline void platform_set_drvdata(struct platform_device *pdev, void *data)目的存储用户在probe()中主动申请的内存区域的指针以防止丢失，

static inline void *platform_get_drvdata(const struct platform_device *pdev)则是将其取出。
函数platform_set_drvdata()和platform_get_drvdata(),定义于..includelinuxplatform_device.h:

static inline void platform_set_drvdata(struct platform_device *pdev, void *data)
{
dev_set_drvdata(&pdev->dev, data);
}
static inline void *platform_get_drvdata(const struct platform_device *pdev)
{
return dev_get_drvdata(&pdev->dev);
}

分析发现，函数platform_set_drvdata()调用了函数dev_set_drvdata(),函数dev_set_drvdata()定义于..includelinuxDd.h:

int dev_set_drv_data(struct device *dev, void *data)
{
int error;

if (!dev->p) {
error = device_private_init(dev);
if (error)
return error;
}
dev->p->driver_data = data;
return 0;
}

将data指向的内存地址赋予了dev->p->driver_data，分析platform_device结构体
platform_device 结构体定义于..includelinuxplatform_device.h：

struct platform_device {
const char * name;
int id;
struct device dev;
u32 num_resources;
struct resource * resource;

const struct platform_device_id *id_entry;

/* MFD cell pointer */
struct mfd_cell *mfd_cell;

/* arch specific additions */
struct pdev_archdata archdata;
};

device 结构体定义于..includelinuxDevice.h：

struct device {
struct device *parent;

struct device_private *p;

struct kobject kobj;
const char *init_name; /* initial name of the device */
const struct device_type *type;

struct mutex mutex; /* mutex to synchronize calls to
* its driver.
*/

struct bus_type *bus; /* type of bus device is on */
struct device_driver *driver; /* which driver has allocated this
device */
void *platform_data; /* Platform specific data, device
core doesn't touch it */
struct dev_pm_info power;
struct dev_pm_domain *pm_domain;

#ifdef CONFIG_NUMA
int numa_node; /* NUMA node this device is close to */
#endif
u64 *dma_mask; /* dma mask (if dma'able device) */
u64 coherent_dma_mask;/* Like dma_mask, but for
alloc_coherent mappings as
not all hardware supports
64 bit addresses for consistent
allocations such descriptors. */

struct device_dma_parameters *dma_parms;

struct list_head dma_pools; /* dma pools (if dma'ble) */

struct dma_coherent_mem *dma_mem; /* internal for coherent mem
override */
/* arch specific additions */
struct dev_archdata archdata;

struct device_node *of_node; /* associated device tree node */

dev_t devt; /* dev_t, creates the sysfs "dev" */
u32 id; /* device instance */

spinlock_t devres_lock;
struct list_head devres_head;

struct klist_node knode_class;
struct class *class;
const struct attribute_group **groups; /* optional groups */

void (*release)(struct device *dev);
};

device_private结构体定义于..driversaseBase.h:
struct device_private {
struct klist klist_children;
struct klist_node knode_parent;
struct klist_node knode_driver;
struct klist_node knode_bus;
struct list_head deferred_probe;
void *driver_data;
struct device *device;
};

————————————————
版权声明：本文为CSDN博主「剑林园主」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/skycover/java/article/details/69950727