分类: LINUX
2016-12-19 10:49:10
A platform机制
platform_driver_register,什么时候调用PROBE函数 注册后如何找到驱动匹配的设备
platform_driver_register(struct platform_driver *drv)注册后如何找到驱动匹配的设备
struct platform_driver {
int (*probe)(struct platform_device *);
int (*remove)(struct platform_device *);
void (*shutdown)(struct platform_device *);
int (*suspend)(struct platform_device *, pm_message_t state);
int (*suspend_late)(struct platform_device *, pm_message_t state);
int (*resume_early)(struct platform_device *);
int (*resume)(struct platform_device *);
struct device_driver driver;
};
BUS首先初始化总线 do_basic_setup()->driver_init()->platform_bus_init()->...初始化platform_bus_type(虚拟总线)
DEVICE生成有2种方法
1 用函数platform_device_register()直接注册一个platform_device设备
2 从dts文件中读出来形成一个platform_device设备
1 设备向内核注册的时候platform_device_register()->platform_device_add()->...内核把设备挂在虚拟的platform bus下
platform_device_register(&physmap_flash); /*这是一个flash驱动例子*/
2 用下面的函数_init gfar_of_init(void) 读取dts文件获得platform_device结构体 /*这是一个mac驱动的例子*/
struct platform_device {
const char * name;
u32 id;
struct device dev;
u32 num_resources;
struct resource * resource;
};
读取的是下面dts里面的结构
{
#address-cells = <0x1>;
#size-cells = <0x0>;
device_type = "network";
model = "eTSEC";
compatible = "gianfar";
reg = <0x24000 0x1000>;
local-mac-address = [00 00 00 00 00 00];
interrupts = <0x1d 0x2 0x1e 0x2 0x22 0x2>;
interrupt-parent = <0x1>;
phy-handle = <0x2>;
phy-connection-type = "sgmii";
};
static int __init gfar_of_init(void) /*在fsl_soc.c文件下的*/
{
struct device_node *np;
unsigned int i;
struct platform_device *gfar_dev;
struct resource res;
int ret;
for (np = NULL, i = 0;
(np = of_find_compatible_node(np, "network", "gianfar")) != NULL;
i++) {
struct resource r[4];
struct device_node *phy, *mdio;
struct gianfar_platform_data gfar_data;
const unsigned int *id;
const char *model;
const char *ctype;
const void *mac_addr;
const phandle *ph;
int n_res = 2;
memset(r, 0, sizeof(r));
memset(&gfar_data, 0, sizeof(gfar_data));
ret = of_address_to_resource(np, 0, &r[0]);
if (ret)
goto err;
of_irq_to_resource(np, 0, &r[1]);
model = of_get_property(np, "model", NULL);
/* If we aren't the FEC we have multiple interrupts */
if (model && strcasecmp(model, "FEC")) {
r[1].name = gfar_tx_intr;
r[2].name = gfar_rx_intr;
of_irq_to_resource(np, 1, &r[2]);
r[3].name = gfar_err_intr;
of_irq_to_resource(np, 2, &r[3]);
n_res += 2;
}
gfar_dev =
platform_device_register_simple("fsl-gianfar", i, &r[0],
n_res);
..........
ret =
platform_device_add_data(gfar_dev, &gfar_data,
sizeof(struct
gianfar_platform_data));
if (ret)
goto unreg;
}
DRIVER驱动注册的时候 platform_driver_register()->driver_register()->bus_add_driver()->driver_attach()->bus_for_each_dev() 对每个挂在虚拟的platform bus的设备作
__driver_attach()->driver_probe_device()->drv->bus->match() 就是下面的platform_match比较strncmp(pdev->name, drv->name, BUS_ID_SIZE),如果相符就调用platform_drv_probe()
->driver->probe(),如果probe成功则绑定该设备到该驱动.
static int platform_match(struct device * dev, struct device_driver * drv)
{
struct platform_device *pdev = container_of(dev, struct platform_device, dev);
return (strncmp(pdev->name, drv->name, BUS_ID_SIZE) == 0);
}
当最后匹配后就调用platform_drv_probe()->driver->probe() 进入驱动的probe()。
B of_platform机制
struct of_platform_driver
{
const char *name;
const struct of_device_id *match_table;
struct module *owner;
int (*probe)(struct of_device* dev,
const struct of_device_id *match);
int (*remove)(struct of_device* dev);
int (*suspend)(struct of_device* dev, pm_message_t state);
int (*resume)(struct of_device* dev);
int (*shutdown)(struct of_device* dev);
struct device_driver driver;
};
struct of_device_id
{
char name[32];
char type[32];
char compatible[128];
#ifdef __KERNEL__
void *data;
#else
kernel_ulong_t data;
#endif
};
BUS首先初始化总线 do_basic_setup()->driver_init()->platform_bus_init()->...初始化of_platform_bus_type(虚拟总线)
DEVICE设备生成用下面的函数mpc8572_register_mtd(void)读取dts文件 获得device_node结构
struct device_node {
const char *name;
const char *type;
phandle node;
phandle linux_phandle;
char *full_name;
struct property *properties;
struct property *deadprops; /* removed properties */
struct device_node *parent;
struct device_node *child;
struct device_node *sibling;
struct device_node *next; /* next device of same type */
struct device_node *allnext; /* next in list of all nodes */
struct proc_dir_entry *pde; /* this node's proc directory */
struct kref kref;
unsigned long _flags;
void *data;
};
读取的是下面dts里面的结构
{
device_type = "rom";
compatible = "direct-mapped";
reg = <0xef800000 0x800000>;
probe-type = "CFI";
bank-width = <0x1>;
partitions = <0x0 0x400000 0x400000 0x8001 0x408000 0x300001 0x708000 0x78001 0x780000 0x80001>;
partition-names = "JFFS2(RW)", "DTB(RO)", "Linux Kernel(RO)", "Parameters(RO)", "U-BOOT(RO)";
};
static int __init mpc8572_register_mtd(void) /*在mpc85xx_ds.c文件中*/
{
struct device_node *np;
np = of_find_compatible_node(NULL, "rom", "direct-mapped");
if (np == NULL)
return 0;
of_platform_device_create(np, np->name, NULL);
return 0;
}
DRIVER驱动注册的时候 platform_driver_register()->driver_register()->bus_add_driver()->driver_attach()->bus_for_each_dev() 对每个挂在虚拟的platform bus的设备作 __driver_attach()->driver_probe_device()->drv->bus->match(), 就是下面的of_platform_bus_match,如果相符就调用 platform_drv_probe()->driver->probe()。
.最终比较的是of_platform_driver.match_table与device_node里面的name,type,compatible。
static int of_platform_bus_match(struct device *dev, struct device_driver *drv)
{
struct of_device *of_dev = to_of_device(dev);
struct of_platform_driver *of_drv = to_of_platform_driver(drv);
const struct of_device_id *matches = of_drv->match_table;
if (!matches)
return 0;
return of_match_device(matches, of_dev) != NULL;
}
const struct of_device_id *of_match_device(const struct of_device_id *matches,
const struct of_device *dev)
{
if (!dev->node)
return NULL;
return of_match_node(matches, dev->node);
}
const struct of_device_id *of_match_node(const struct of_device_id *matches,
const struct device_node *node)
{
while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
int match = 1;
if (matches->name[0])
match &= node->name
&& !strcmp(matches->name, node->name);
if (matches->type[0])
match &= node->type
&& !strcmp(matches->type, node->type);
if (matches->compatible[0])
match &= of_device_is_compatible(node,
matches->compatible);
if (match)
return matches;
matches++;
}
return NULL;
}
当最后匹配后就调用platform_drv_probe()->driver->probe() 进入驱动的probe()。