uboot-DM驅動模型

代碼：u-boot-xlnx-xilinx

DM模型

先看一下uboot的驅動模型Driver Mode。
DM 是 U-Boot 中的驅動框架，全稱 Driver Mode。
udevice 描述具體的某一個硬件設備。
driver 是與這個設備匹配的驅動。
uclass 是同一類設備的抽象，提供管理同一類設備的抽象接口。

struct udevice

/**
 * struct udevice - An instance of a driver
 *
 * This holds information about a device, which is a driver bound to a
 * particular port or peripheral (essentially a driver instance).
 *
 * A device will come into existence through a 'bind' call, either due to
 * a U_BOOT_DEVICE() macro (in which case platdata is non-NULL) or a node
 * in the device tree (in which case of_offset is >= 0). In the latter case
 * we translate the device tree information into platdata in a function
 * implemented by the driver ofdata_to_platdata method (called just before the
 * probe method if the device has a device tree node.
 *
 * All three of platdata, priv and uclass_priv can be allocated by the
 * driver, or you can use the auto_alloc_size members of struct driver and
 * struct uclass_driver to have driver model do this automatically.
 *
 * @driver: The driver used by this device
 * @name: Name of device, typically the FDT node name
 * @platdata: Configuration data for this device
 * @parent_platdata: The parent bus's configuration data for this device
 * @uclass_platdata: The uclass's configuration data for this device
 * @of_offset: Device tree node offset for this device (- for none)
 * @driver_data: Driver data word for the entry that matched this device with
 *		its driver
 * @parent: Parent of this device, or NULL for the top level device
 * @priv: Private data for this device
 * @uclass: Pointer to uclass for this device
 * @uclass_priv: The uclass's private data for this device
 * @parent_priv: The parent's private data for this device
 * @uclass_node: Used by uclass to link its devices
 * @child_head: List of children of this device
 * @sibling_node: Next device in list of all devices
 * @flags: Flags for this device DM_FLAG_...
 * @req_seq: Requested sequence number for this device (-1 = any)
 * @seq: Allocated sequence number for this device (-1 = none). This is set up
 * when the device is probed and will be unique within the device's uclass.
 * @devres_head: List of memory allocations associated with this device.
 *		When CONFIG_DEVRES is enabled, devm_kmalloc() and friends will
 *		add to this list. Memory so-allocated will be freed
 *		automatically when the device is removed / unbound
 */
struct udevice {
	const struct driver *driver;
	const char *name;
	void *platdata;
	void *parent_platdata;
	void *uclass_platdata;
	int of_offset;
	ulong driver_data;
	struct udevice *parent;
	void *priv;
	struct uclass *uclass;
	void *uclass_priv;
	void *parent_priv;
	struct list_head uclass_node;
	struct list_head child_head;
	struct list_head sibling_node;
	uint32_t flags;
	int req_seq;
	int seq;
#ifdef CONFIG_DEVRES
	struct list_head devres_head;
#endif
};

struct driver

/**
 * struct driver - A driver for a feature or peripheral
 *
 * This holds methods for setting up a new device, and also removing it.
 * The device needs information to set itself up - this is provided either
 * by platdata or a device tree node (which we find by looking up
 * matching compatible strings with of_match).
 *
 * Drivers all belong to a uclass, representing a class of devices of the
 * same type. Common elements of the drivers can be implemented in the uclass,
 * or the uclass can provide a consistent interface to the drivers within
 * it.
 *
 * @name: Device name
 * @id: Identiies the uclass we belong to
 * @of_match: List of compatible strings to match, and any identifying data
 * for each.
 * @bind: Called to bind a device to its driver
 * @probe: Called to probe a device, i.e. activate it
 * @remove: Called to remove a device, i.e. de-activate it
 * @unbind: Called to unbind a device from its driver
 * @ofdata_to_platdata: Called before probe to decode device tree data
 * @child_post_bind: Called after a new child has been bound
 * @child_pre_probe: Called before a child device is probed. The device has
 * memory allocated but it has not yet been probed.
 * @child_post_remove: Called after a child device is removed. The device
 * has memory allocated but its device_remove() method has been called.
 * @priv_auto_alloc_size: If non-zero this is the size of the private data
 * to be allocated in the device's ->priv pointer. If zero, then the driver
 * is responsible for allocating any data required.
 * @platdata_auto_alloc_size: If non-zero this is the size of the
 * platform data to be allocated in the device's ->platdata pointer.
 * This is typically only useful for device-tree-aware drivers (those with
 * an of_match), since drivers which use platdata will have the data
 * provided in the U_BOOT_DEVICE() instantiation.
 * @per_child_auto_alloc_size: Each device can hold private data owned by
 * its parent. If required this will be automatically allocated if this
 * value is non-zero.
 * @per_child_platdata_auto_alloc_size: A bus likes to store information about
 * its children. If non-zero this is the size of this data, to be allocated
 * in the child's parent_platdata pointer.
 * @ops: Driver-specific operations. This is typically a list of function
 * pointers defined by the driver, to implement driver functions required by
 * the uclass.
 * @flags: driver flags - see DM_FLAGS_...
 */
struct driver {
	char *name;
	enum uclass_id id;
	const struct udevice_id *of_match;
	int (*bind)(struct udevice *dev);
	int (*probe)(struct udevice *dev);
	int (*remove)(struct udevice *dev);
	int (*unbind)(struct udevice *dev);
	int (*ofdata_to_platdata)(struct udevice *dev);
	int (*child_post_bind)(struct udevice *dev);
	int (*child_pre_probe)(struct udevice *dev);
	int (*child_post_remove)(struct udevice *dev);
	int priv_auto_alloc_size;
	int platdata_auto_alloc_size;
	int per_child_auto_alloc_size;
	int per_child_platdata_auto_alloc_size;
	const void *ops;	/* driver-specific operations */
	uint32_t flags;
};

uclass_driver

/**
 * struct uclass_driver - Driver for the uclass
 *
 * A uclass_driver provides a consistent interface to a set of related
 * drivers.
 *
 * @name: Name of uclass driver
 * @id: ID number of this uclass
 * @post_bind: Called after a new device is bound to this uclass
 * @pre_unbind: Called before a device is unbound from this uclass
 * @pre_probe: Called before a new device is probed
 * @post_probe: Called after a new device is probed
 * @pre_remove: Called before a device is removed
 * @child_post_bind: Called after a child is bound to a device in this uclass
 * @init: Called to set up the uclass
 * @destroy: Called to destroy the uclass
 * @priv_auto_alloc_size: If non-zero this is the size of the private data
 * to be allocated in the uclass's ->priv pointer. If zero, then the uclass
 * driver is responsible for allocating any data required.
 * @per_device_auto_alloc_size: Each device can hold private data owned
 * by the uclass. If required this will be automatically allocated if this
 * value is non-zero.
 * @per_device_platdata_auto_alloc_size: Each device can hold platform data
 * owned by the uclass as 'dev->uclass_platdata'. If the value is non-zero,
 * then this will be automatically allocated.
 * @per_child_auto_alloc_size: Each child device (of a parent in this
 * uclass) can hold parent data for the device/uclass. This value is only
 * used as a falback if this member is 0 in the driver.
 * @per_child_platdata_auto_alloc_size: A bus likes to store information about
 * its children. If non-zero this is the size of this data, to be allocated
 * in the child device's parent_platdata pointer. This value is only used as
 * a falback if this member is 0 in the driver.
 * @ops: Uclass operations, providing the consistent interface to devices
 * within the uclass.
 * @flags: Flags for this uclass (DM_UC_...)
 */
struct uclass_driver {
	const char *name;
	enum uclass_id id;
	int (*post_bind)(struct udevice *dev);
	int (*pre_unbind)(struct udevice *dev);
	int (*pre_probe)(struct udevice *dev);
	int (*post_probe)(struct udevice *dev);
	int (*pre_remove)(struct udevice *dev);
	int (*child_post_bind)(struct udevice *dev);
	int (*child_pre_probe)(struct udevice *dev);
	int (*init)(struct uclass *class);
	int (*destroy)(struct uclass *class);
	int priv_auto_alloc_size;
	int per_device_auto_alloc_size;
	int per_device_platdata_auto_alloc_size;
	int per_child_auto_alloc_size;
	int per_child_platdata_auto_alloc_size;
	const void *ops;
	uint32_t flags;
};

##驅動初始化
驅動模型初始化函數入口爲initf_dm和initr_dm，initr_dm爲代碼重定位後的。

看一下initr_dm，
initr_dm

static int initr_dm(void)
{
	int ret;

	/* Save the pre-reloc driver model and start a new one */
	gd->dm_root_f = gd->dm_root; //把initf_dm初始化保存
	gd->dm_root = NULL;
#ifdef CONFIG_TIMER
	gd->timer = NULL;
#endif
	ret = dm_init_and_scan(false); //掃描設備和驅動進行初始化
	if (ret)
		return ret;
#ifdef CONFIG_TIMER_EARLY
	ret = dm_timer_init();
	if (ret)
		return ret;
#endif

	return 0;
}

dm_init_and_scan
掃描設備和驅動進行初始化，掃描U_BOOT_DEVICE定義設備，dtb中定義設備，並尋找匹配對應的驅動，並綁定和probe。

int dm_init_and_scan(bool pre_reloc_only)
{
	int ret;

	ret = dm_init(); //初始化根驅動gd->dm_root
	
	ret = dm_scan_platdata(pre_reloc_only);初始化用U_BOOT_DEVICE定義的設備驅動，並綁定驅動，進行probe
	

	if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) {
		ret = dm_scan_fdt(gd->fdt_blob, pre_reloc_only);初始化用dtb中定義的設備驅動，並綁定驅動，進行probe
		
	}

	ret = dm_scan_other(pre_reloc_only);
	

	return 0;
}

#define U_BOOT_DEVICE(__name)						\
	ll_entry_declare(struct driver_info, __name, driver_info)

看一下dm_scan_fdt–》dm_scan_fdt_node
dm_scan_fdt_node

int dm_scan_fdt_node(struct udevice *parent, const void *blob, int offset,
		     bool pre_reloc_only)
{
	int ret = 0, err;
	
	//遍歷dtb
	for (offset = fdt_first_subnode(blob, offset);
	     offset > 0;
	     offset = fdt_next_subnode(blob, offset)) {
		if (pre_reloc_only &&
		    !fdt_getprop(blob, offset, "u-boot,dm-pre-reloc", NULL))
			continue;
		if (!fdtdec_get_is_enabled(blob, offset)) {
			dm_dbg("   - ignoring disabled device\n");
			continue;
		}
		err = lists_bind_fdt(parent, blob, offset, NULL); //綁定驅動

	}

	return ret;
}

lists_bind_fdt

int lists_bind_fdt(struct udevice *parent, const void *blob, int offset,
		   struct udevice **devp)
{
	struct driver *driver = ll_entry_start(struct driver, driver);//驅動都用U_BOOT_DRIVER定義，插入u_boot_list_2_ 段
	const int n_ents = ll_entry_count(struct driver, driver);
	const struct udevice_id *id;
	struct driver *entry;
	struct udevice *dev;
	bool found = false;
	const char *name, *compat_list, *compat;
	int compat_length, i;
	int result = 0;
	int ret = 0;

	name = fdt_get_name(blob, offset, NULL);
	

	compat_list = fdt_getprop(blob, offset, "compatible", &compat_length); //compatible用來匹配的關鍵詞
	

	/*
	 * Walk through the compatible string list, attempting to match each
	 * compatible string in order such that we match in order of priority
	 * from the first string to the last.
	 */
	for (i = 0; i < compat_length; i += strlen(compat) + 1) {
		compat = compat_list + i;
	
		for (entry = driver; entry != driver + n_ents; entry++) {
			ret = driver_check_compatible(entry->of_match, &id,
						      compat); //匹配驅動和設備
			if (!ret)
				break;
		}
		if (entry == driver + n_ents)
			continue;

		上面匹配成功，這裏進行bing
		ret = device_bind_with_driver_data(parent, entry, name,
						   id->data, offset, &dev);
		
			found = true;
			if (devp)
				*devp = dev;
		}
		break;
	}

	return result;
}

U_BOOT_DRIVER

/* Declare a new U-Boot driver */
#define U_BOOT_DRIVER(__name)						\
	ll_entry_declare(struct driver, __name, driver)

#define ll_entry_declare(_type, _name, _list)				\
	_type _u_boot_list_2_##_list##_2_##_name __aligned(4)		\
			__attribute__((unused,				\
			section(".u_boot_list_2_"#_list"_2_"#_name)))

device_bind_common

static int device_bind_common(struct udevice *parent, const struct driver *drv,
			      const char *name, void *platdata,
			      ulong driver_data, int of_offset,
			      uint of_platdata_size, struct udevice **devp)
{
	struct udevice *dev;
	struct uclass *uc;
	int size, ret = 0;

	

	ret = uclass_get(drv->id, &uc); //這裏根據id查找同類uclass驅，如果沒有，就新建一個uclass


	dev = calloc(1, sizeof(struct udevice));//分配一個udevice，代表設備
	
    //基本初始化
	INIT_LIST_HEAD(&dev->sibling_node);
	INIT_LIST_HEAD(&dev->child_head);
	INIT_LIST_HEAD(&dev->uclass_node);
#ifdef CONFIG_DEVRES
	INIT_LIST_HEAD(&dev->devres_head);
#endif
	dev->platdata = platdata;//指向設備platdata
	dev->driver_data = driver_data;
	dev->name = name;//驅動名字
	dev->of_offset = of_offset;
	dev->parent = parent;
	dev->driver = drv; //指向驅動
	dev->uclass = uc;

	dev->seq = -1;
	dev->req_seq = -1;
	if (CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(DM_SEQ_ALIAS)) {
		/*
		 * Some devices, such as a SPI bus, I2C bus and serial ports
		 * are numbered using aliases.
		 *
		 * This is just a 'requested' sequence, and will be
		 * resolved (and ->seq updated) when the device is probed.
		 */
		if (uc->uc_drv->flags & DM_UC_FLAG_SEQ_ALIAS) {
			if (uc->uc_drv->name && of_offset != -1) {
				fdtdec_get_alias_seq(gd->fdt_blob,
						uc->uc_drv->name, of_offset,
						&dev->req_seq);
			}
		}
	}

	if (drv->platdata_auto_alloc_size) {
		bool alloc = !platdata;

		if (CONFIG_IS_ENABLED(OF_PLATDATA)) {
			if (of_platdata_size) {
				dev->flags |= DM_FLAG_OF_PLATDATA;
				if (of_platdata_size <
						drv->platdata_auto_alloc_size)
					alloc = true;
			}
		}
		if (alloc) {
			dev->flags |= DM_FLAG_ALLOC_PDATA;
			dev->platdata = calloc(1,
					       drv->platdata_auto_alloc_size);
			if (!dev->platdata) {
				ret = -ENOMEM;
				goto fail_alloc1;
			}
			if (CONFIG_IS_ENABLED(OF_PLATDATA) && platdata) {
				memcpy(dev->platdata, platdata,
				       of_platdata_size);
			}
		}
	}

	size = uc->uc_drv->per_device_platdata_auto_alloc_size;
	if (size) {
		dev->flags |= DM_FLAG_ALLOC_UCLASS_PDATA;
		dev->uclass_platdata = calloc(1, size);
		if (!dev->uclass_platdata) {
			ret = -ENOMEM;
			goto fail_alloc2;
		}
	}

	if (parent) {
		size = parent->driver->per_child_platdata_auto_alloc_size;
		if (!size) {
			size = parent->uclass->uc_drv->
					per_child_platdata_auto_alloc_size;
		}
		if (size) {
			dev->flags |= DM_FLAG_ALLOC_PARENT_PDATA;
			dev->parent_platdata = calloc(1, size);
			if (!dev->parent_platdata) {
				ret = -ENOMEM;
				goto fail_alloc3;
			}
		}
	}

	/* put dev into parent's successor list */
	if (parent)
		list_add_tail(&dev->sibling_node, &parent->child_head); //驅動拓撲結構

	ret = uclass_bind_device(dev);//uclass驅動的bind
	if (ret)
		goto fail_uclass_bind;

	/* if we fail to bind we remove device from successors and free it */
	if (drv->bind) {
		ret = drv->bind(dev); //driver 驅動的bind
		if (ret)
			goto fail_bind;
	}
	if (parent && parent->driver->child_post_bind) {
		ret = parent->driver->child_post_bind(dev);
		if (ret)
			goto fail_child_post_bind;
	}
	if (uc->uc_drv->post_bind) {
		ret = uc->uc_drv->post_bind(dev);
		if (ret)
			goto fail_uclass_post_bind;
	}

	if (parent)
		dm_dbg("Bound device %s to %s\n", dev->name, parent->name);
	if (devp)
		*devp = dev;

	dev->flags |= DM_FLAG_BOUND;

	return 0;


}