drivers/block/blk-uclass.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2016 Google, Inc
  * Written by Simon Glass <sjg@chromium.org>
  */

 #include <common.h>
 #include <blk.h>
 #include <dm.h>
 #include <log.h>
 #include <malloc.h>
 #include <part.h>
 #include <dm/device-internal.h>
 #include <dm/lists.h>
 #include <dm/uclass-internal.h>
 #include <linux/err.h>

 static const char *if_typename_str[IF_TYPE_COUNT] = {
 	[IF_TYPE_IDE]		= "ide",
 	[IF_TYPE_SCSI]		= "scsi",
 	[IF_TYPE_ATAPI]		= "atapi",
 	[IF_TYPE_USB]		= "usb",
 	[IF_TYPE_DOC]		= "doc",
 	[IF_TYPE_MMC]		= "mmc",
 	[IF_TYPE_SD]		= "sd",
 	[IF_TYPE_SATA]		= "sata",
 	[IF_TYPE_HOST]		= "host",
 	[IF_TYPE_NVME]		= "nvme",
 	[IF_TYPE_EFI]		= "efi",
 	[IF_TYPE_VIRTIO]	= "virtio",
 	[IF_TYPE_PVBLOCK]	= "pvblock",
 };

 static enum uclass_id if_type_uclass_id[IF_TYPE_COUNT] = {
 	[IF_TYPE_IDE]		= UCLASS_IDE,
 	[IF_TYPE_SCSI]		= UCLASS_SCSI,
 	[IF_TYPE_ATAPI]		= UCLASS_INVALID,
 	[IF_TYPE_USB]		= UCLASS_MASS_STORAGE,
 	[IF_TYPE_DOC]		= UCLASS_INVALID,
 	[IF_TYPE_MMC]		= UCLASS_MMC,
 	[IF_TYPE_SD]		= UCLASS_INVALID,
 	[IF_TYPE_SATA]		= UCLASS_AHCI,
 	[IF_TYPE_HOST]		= UCLASS_ROOT,
 	[IF_TYPE_NVME]		= UCLASS_NVME,
 	[IF_TYPE_EFI]		= UCLASS_EFI,
 	[IF_TYPE_VIRTIO]	= UCLASS_VIRTIO,
 	[IF_TYPE_PVBLOCK]	= UCLASS_PVBLOCK,
 };

 static enum if_type if_typename_to_iftype(const char *if_typename)
 {
 	int i;

 	for (i = 0; i < IF_TYPE_COUNT; i++) {
 		if (if_typename_str[i] &&
 		    !strcmp(if_typename, if_typename_str[i]))
 			return i;
 	}

 	return IF_TYPE_UNKNOWN;
 }

 static enum uclass_id if_type_to_uclass_id(enum if_type if_type)
 {
 	return if_type_uclass_id[if_type];
 }

 const char *blk_get_if_type_name(enum if_type if_type)
 {
 	return if_typename_str[if_type];
 }

 struct blk_desc *blk_get_devnum_by_type(enum if_type if_type, int devnum)
 {
 	struct blk_desc *desc;
 	struct udevice *dev;
 	int ret;

 	ret = blk_get_device(if_type, devnum, &dev);
 	if (ret)
 		return NULL;
 	desc = dev_get_uclass_platdata(dev);

 	return desc;
 }

 /*
  * This function is complicated with driver model. We look up the interface
  * name in a local table. This gives us an interface type which we can match
  * against the uclass of the block device's parent.
  */
 struct blk_desc *blk_get_devnum_by_typename(const char *if_typename, int devnum)
 {
 	enum uclass_id uclass_id;
 	enum if_type if_type;
 	struct udevice *dev;
 	struct uclass *uc;
 	int ret;

 	if_type = if_typename_to_iftype(if_typename);
 	if (if_type == IF_TYPE_UNKNOWN) {
 		debug("%s: Unknown interface type '%s'\n", __func__,
 		      if_typename);
 		return NULL;
 	}
 	uclass_id = if_type_to_uclass_id(if_type);
 	if (uclass_id == UCLASS_INVALID) {
 		debug("%s: Unknown uclass for interface type'\n",
 		      if_typename_str[if_type]);
 		return NULL;
 	}

 	ret = uclass_get(UCLASS_BLK, &uc);
 	if (ret)
 		return NULL;
 	uclass_foreach_dev(dev, uc) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		debug("%s: if_type=%d, devnum=%d: %s, %d, %d\n", __func__,
 		      if_type, devnum, dev->name, desc->if_type, desc->devnum);
 		if (desc->devnum != devnum)
 			continue;

 		/* Find out the parent device uclass */
 		if (device_get_uclass_id(dev->parent) != uclass_id) {
 			debug("%s: parent uclass %d, this dev %d\n", __func__,
 			      device_get_uclass_id(dev->parent), uclass_id);
 			continue;
 		}

 		if (device_probe(dev))
 			return NULL;

 		debug("%s: Device desc %p\n", __func__, desc);
 		return desc;
 	}
 	debug("%s: No device found\n", __func__);

 	return NULL;
 }

 /**
  * blk_get_by_device() - Get the block device descriptor for the given device
  * @dev:	Instance of a storage device
  *
  * Return: With block device descriptor on success , NULL if there is no such
  *	   block device.
  */
 struct blk_desc *blk_get_by_device(struct udevice *dev)
 {
 	struct udevice *child_dev;

 	device_foreach_child(child_dev, dev) {
 		if (device_get_uclass_id(child_dev) != UCLASS_BLK)
 			continue;

 		return dev_get_uclass_platdata(child_dev);
 	}

 	debug("%s: No block device found\n", __func__);

 	return NULL;
 }

 /**
  * get_desc() - Get the block device descriptor for the given device number
  *
  * @if_type:	Interface type
  * @devnum:	Device number (0 = first)
  * @descp:	Returns block device descriptor on success
  * @return 0 on success, -ENODEV if there is no such device and no device
  * with a higher device number, -ENOENT if there is no such device but there
  * is one with a higher number, or other -ve on other error.
  */
 static int get_desc(enum if_type if_type, int devnum, struct blk_desc **descp)
 {
 	bool found_more = false;
 	struct udevice *dev;
 	struct uclass *uc;
 	int ret;

 	*descp = NULL;
 	ret = uclass_get(UCLASS_BLK, &uc);
 	if (ret)
 		return ret;
 	uclass_foreach_dev(dev, uc) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		debug("%s: if_type=%d, devnum=%d: %s, %d, %d\n", __func__,
 		      if_type, devnum, dev->name, desc->if_type, desc->devnum);
 		if (desc->if_type == if_type) {
 			if (desc->devnum == devnum) {
 				ret = device_probe(dev);
 				if (ret)
 					return ret;

 				*descp = desc;
 				return 0;
 			} else if (desc->devnum > devnum) {
 				found_more = true;
 			}
 		}
 	}

 	return found_more ? -ENOENT : -ENODEV;
 }

 int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart)
 {
 	struct udevice *dev;
 	int ret;

 	ret = blk_get_device(if_type, devnum, &dev);
 	if (ret)
 		return ret;

 	return blk_select_hwpart(dev, hwpart);
 }

 int blk_list_part(enum if_type if_type)
 {
 	struct blk_desc *desc;
 	int devnum, ok;
 	int ret;

 	for (ok = 0, devnum = 0;; ++devnum) {
 		ret = get_desc(if_type, devnum, &desc);
 		if (ret == -ENODEV)
 			break;
 		else if (ret)
 			continue;
 		if (desc->part_type != PART_TYPE_UNKNOWN) {
 			++ok;
 			if (devnum)
 				putc('\n');
 			part_print(desc);
 		}
 	}
 	if (!ok)
 		return -ENODEV;

 	return 0;
 }

 int blk_print_part_devnum(enum if_type if_type, int devnum)
 {
 	struct blk_desc *desc;
 	int ret;

 	ret = get_desc(if_type, devnum, &desc);
 	if (ret)
 		return ret;
 	if (desc->type == DEV_TYPE_UNKNOWN)
 		return -ENOENT;
 	part_print(desc);

 	return 0;
 }

 void blk_list_devices(enum if_type if_type)
 {
 	struct blk_desc *desc;
 	int ret;
 	int i;

 	for (i = 0;; ++i) {
 		ret = get_desc(if_type, i, &desc);
 		if (ret == -ENODEV)
 			break;
 		else if (ret)
 			continue;
 		if (desc->type == DEV_TYPE_UNKNOWN)
 			continue;  /* list only known devices */
 		printf("Device %d: ", i);
 		dev_print(desc);
 	}
 }

 int blk_print_device_num(enum if_type if_type, int devnum)
 {
 	struct blk_desc *desc;
 	int ret;

 	ret = get_desc(if_type, devnum, &desc);
 	if (ret)
 		return ret;
 	printf("\nIDE device %d: ", devnum);
 	dev_print(desc);

 	return 0;
 }

 int blk_show_device(enum if_type if_type, int devnum)
 {
 	struct blk_desc *desc;
 	int ret;

 	printf("\nDevice %d: ", devnum);
 	ret = get_desc(if_type, devnum, &desc);
 	if (ret == -ENODEV || ret == -ENOENT) {
 		printf("unknown device\n");
 		return -ENODEV;
 	}
 	if (ret)
 		return ret;
 	dev_print(desc);

 	if (desc->type == DEV_TYPE_UNKNOWN)
 		return -ENOENT;

 	return 0;
 }

 ulong blk_read_devnum(enum if_type if_type, int devnum, lbaint_t start,
 		      lbaint_t blkcnt, void *buffer)
 {
 	struct blk_desc *desc;
 	ulong n;
 	int ret;

 	ret = get_desc(if_type, devnum, &desc);
 	if (ret)
 		return ret;
 	n = blk_dread(desc, start, blkcnt, buffer);
 	if (IS_ERR_VALUE(n))
 		return n;

 	return n;
 }

 ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
 		       lbaint_t blkcnt, const void *buffer)
 {
 	struct blk_desc *desc;
 	int ret;

 	ret = get_desc(if_type, devnum, &desc);
 	if (ret)
 		return ret;
 	return blk_dwrite(desc, start, blkcnt, buffer);
 }

 int blk_select_hwpart(struct udevice *dev, int hwpart)
 {
 	const struct blk_ops *ops = blk_get_ops(dev);

 	if (!ops)
 		return -ENOSYS;
 	if (!ops->select_hwpart)
 		return 0;

 	return ops->select_hwpart(dev, hwpart);
 }

 int blk_dselect_hwpart(struct blk_desc *desc, int hwpart)
 {
 	return blk_select_hwpart(desc->bdev, hwpart);
 }

 int blk_first_device(int if_type, struct udevice **devp)
 {
 	struct blk_desc *desc;
 	int ret;

 	ret = uclass_find_first_device(UCLASS_BLK, devp);
 	if (ret)
 		return ret;
 	if (!*devp)
 		return -ENODEV;
 	do {
 		desc = dev_get_uclass_platdata(*devp);
 		if (desc->if_type == if_type)
 			return 0;
 		ret = uclass_find_next_device(devp);
 		if (ret)
 			return ret;
 	} while (*devp);

 	return -ENODEV;
 }

 int blk_next_device(struct udevice **devp)
 {
 	struct blk_desc *desc;
 	int ret, if_type;

 	desc = dev_get_uclass_platdata(*devp);
 	if_type = desc->if_type;
 	do {
 		ret = uclass_find_next_device(devp);
 		if (ret)
 			return ret;
 		if (!*devp)
 			return -ENODEV;
 		desc = dev_get_uclass_platdata(*devp);
 		if (desc->if_type == if_type)
 			return 0;
 	} while (1);
 }

 int blk_find_device(int if_type, int devnum, struct udevice **devp)
 {
 	struct uclass *uc;
 	struct udevice *dev;
 	int ret;

 	ret = uclass_get(UCLASS_BLK, &uc);
 	if (ret)
 		return ret;
 	uclass_foreach_dev(dev, uc) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		debug("%s: if_type=%d, devnum=%d: %s, %d, %d\n", __func__,
 		      if_type, devnum, dev->name, desc->if_type, desc->devnum);
 		if (desc->if_type == if_type && desc->devnum == devnum) {
 			*devp = dev;
 			return 0;
 		}
 	}

 	return -ENODEV;
 }

 int blk_get_device(int if_type, int devnum, struct udevice **devp)
 {
 	int ret;

 	ret = blk_find_device(if_type, devnum, devp);
 	if (ret)
 		return ret;

 	return device_probe(*devp);
 }

 unsigned long blk_dread(struct blk_desc *block_dev, lbaint_t start,
 			lbaint_t blkcnt, void *buffer)
 {
 	struct udevice *dev = block_dev->bdev;
 	const struct blk_ops *ops = blk_get_ops(dev);
 	ulong blks_read;

 	if (!ops->read)
 		return -ENOSYS;

 	if (blkcache_read(block_dev->if_type, block_dev->devnum,
 			  start, blkcnt, block_dev->blksz, buffer))
 		return blkcnt;
 	blks_read = ops->read(dev, start, blkcnt, buffer);
 	if (blks_read == blkcnt)
 		blkcache_fill(block_dev->if_type, block_dev->devnum,
 			      start, blkcnt, block_dev->blksz, buffer);

 	return blks_read;
 }

 unsigned long blk_dwrite(struct blk_desc *block_dev, lbaint_t start,
 			 lbaint_t blkcnt, const void *buffer)
 {
 	struct udevice *dev = block_dev->bdev;
 	const struct blk_ops *ops = blk_get_ops(dev);

 	if (!ops->write)
 		return -ENOSYS;

 	blkcache_invalidate(block_dev->if_type, block_dev->devnum);
 	return ops->write(dev, start, blkcnt, buffer);
 }

 unsigned long blk_derase(struct blk_desc *block_dev, lbaint_t start,
 			 lbaint_t blkcnt)
 {
 	struct udevice *dev = block_dev->bdev;
 	const struct blk_ops *ops = blk_get_ops(dev);

 	if (!ops->erase)
 		return -ENOSYS;

 	blkcache_invalidate(block_dev->if_type, block_dev->devnum);
 	return ops->erase(dev, start, blkcnt);
 }

 int blk_get_from_parent(struct udevice *parent, struct udevice **devp)
 {
 	struct udevice *dev;
 	enum uclass_id id;
 	int ret;

 	device_find_first_child(parent, &dev);
 	if (!dev) {
 		debug("%s: No block device found for parent '%s'\n", __func__,
 		      parent->name);
 		return -ENODEV;
 	}
 	id = device_get_uclass_id(dev);
 	if (id != UCLASS_BLK) {
 		debug("%s: Incorrect uclass %s for block device '%s'\n",
 		      __func__, uclass_get_name(id), dev->name);
 		return -ENOTBLK;
 	}
 	ret = device_probe(dev);
 	if (ret)
 		return ret;
 	*devp = dev;

 	return 0;
 }

 int blk_find_max_devnum(enum if_type if_type)
 {
 	struct udevice *dev;
 	int max_devnum = -ENODEV;
 	struct uclass *uc;
 	int ret;

 	ret = uclass_get(UCLASS_BLK, &uc);
 	if (ret)
 		return ret;
 	uclass_foreach_dev(dev, uc) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		if (desc->if_type == if_type && desc->devnum > max_devnum)
 			max_devnum = desc->devnum;
 	}

 	return max_devnum;
 }

 int blk_next_free_devnum(enum if_type if_type)
 {
 	int ret;

 	ret = blk_find_max_devnum(if_type);
 	if (ret == -ENODEV)
 		return 0;
 	if (ret < 0)
 		return ret;

 	return ret + 1;
 }

 static int blk_claim_devnum(enum if_type if_type, int devnum)
 {
 	struct udevice *dev;
 	struct uclass *uc;
 	int ret;

 	ret = uclass_get(UCLASS_BLK, &uc);
 	if (ret)
 		return ret;
 	uclass_foreach_dev(dev, uc) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		if (desc->if_type == if_type && desc->devnum == devnum) {
 			int next = blk_next_free_devnum(if_type);

 			if (next < 0)
 				return next;
 			desc->devnum = next;
 			return 0;
 		}
 	}

 	return -ENOENT;
 }

 int blk_create_device(struct udevice *parent, const char *drv_name,
 		      const char *name, int if_type, int devnum, int blksz,
 		      lbaint_t lba, struct udevice **devp)
 {
 	struct blk_desc *desc;
 	struct udevice *dev;
 	int ret;

 	if (devnum == -1) {
 		devnum = blk_next_free_devnum(if_type);
 	} else {
 		ret = blk_claim_devnum(if_type, devnum);
 		if (ret < 0 && ret != -ENOENT)
 			return ret;
 	}
 	if (devnum < 0)
 		return devnum;
 	ret = device_bind_driver(parent, drv_name, name, &dev);
 	if (ret)
 		return ret;
 	desc = dev_get_uclass_platdata(dev);
 	desc->if_type = if_type;
 	desc->blksz = blksz;
 	desc->log2blksz = LOG2(desc->blksz);
 	desc->lba = lba;
 	desc->part_type = PART_TYPE_UNKNOWN;
 	desc->bdev = dev;
 	desc->devnum = devnum;
 	*devp = dev;

 	return 0;
 }

 int blk_create_devicef(struct udevice *parent, const char *drv_name,
 		       const char *name, int if_type, int devnum, int blksz,
 		       lbaint_t lba, struct udevice **devp)
 {
 	char dev_name[30], *str;
 	int ret;

 	snprintf(dev_name, sizeof(dev_name), "%s.%s", parent->name, name);
 	str = strdup(dev_name);
 	if (!str)
 		return -ENOMEM;

 	ret = blk_create_device(parent, drv_name, str, if_type, devnum,
 				blksz, lba, devp);
 	if (ret) {
 		free(str);
 		return ret;
 	}
 	device_set_name_alloced(*devp);

 	return 0;
 }

 int blk_unbind_all(int if_type)
 {
 	struct uclass *uc;
 	struct udevice *dev, *next;
 	int ret;

 	ret = uclass_get(UCLASS_BLK, &uc);
 	if (ret)
 		return ret;
 	uclass_foreach_dev_safe(dev, next, uc) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		if (desc->if_type == if_type) {
 			ret = device_remove(dev, DM_REMOVE_NORMAL);
 			if (ret)
 				return ret;
 			ret = device_unbind(dev);
 			if (ret)
 				return ret;
 		}
 	}

 	return 0;
 }

 static int blk_post_probe(struct udevice *dev)
 {
 	if (IS_ENABLED(CONFIG_PARTITIONS) &&
 	    IS_ENABLED(CONFIG_HAVE_BLOCK_DEVICE)) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);

 		part_init(desc);
 	}

 	return 0;
 }

 UCLASS_DRIVER(blk) = {
 	.id		= UCLASS_BLK,
 	.name		= "blk",
 	.post_probe	= blk_post_probe,
 	.per_device_platdata_auto_alloc_size = sizeof(struct blk_desc),
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2016 Google, Inc
	* Written by Simon Glass <sjg@chromium.org>
	*/

	#include <common.h>
	#include <blk.h>
	#include <dm.h>
	#include <log.h>
	#include <malloc.h>
	#include <part.h>
	#include <dm/device-internal.h>
	#include <dm/lists.h>
	#include <dm/uclass-internal.h>
	#include <linux/err.h>

	static const char *if_typename_str[IF_TYPE_COUNT] = {
	[IF_TYPE_IDE] = "ide",
	[IF_TYPE_SCSI] = "scsi",
	[IF_TYPE_ATAPI] = "atapi",
	[IF_TYPE_USB] = "usb",
	[IF_TYPE_DOC] = "doc",
	[IF_TYPE_MMC] = "mmc",
	[IF_TYPE_SD] = "sd",
	[IF_TYPE_SATA] = "sata",
	[IF_TYPE_HOST] = "host",
	[IF_TYPE_NVME] = "nvme",
	[IF_TYPE_EFI] = "efi",
	[IF_TYPE_VIRTIO] = "virtio",
	[IF_TYPE_PVBLOCK] = "pvblock",
	};

	static enum uclass_id if_type_uclass_id[IF_TYPE_COUNT] = {
	[IF_TYPE_IDE] = UCLASS_IDE,
	[IF_TYPE_SCSI] = UCLASS_SCSI,
	[IF_TYPE_ATAPI] = UCLASS_INVALID,
	[IF_TYPE_USB] = UCLASS_MASS_STORAGE,
	[IF_TYPE_DOC] = UCLASS_INVALID,
	[IF_TYPE_MMC] = UCLASS_MMC,
	[IF_TYPE_SD] = UCLASS_INVALID,
	[IF_TYPE_SATA] = UCLASS_AHCI,
	[IF_TYPE_HOST] = UCLASS_ROOT,
	[IF_TYPE_NVME] = UCLASS_NVME,
	[IF_TYPE_EFI] = UCLASS_EFI,
	[IF_TYPE_VIRTIO] = UCLASS_VIRTIO,
	[IF_TYPE_PVBLOCK] = UCLASS_PVBLOCK,
	};

	static enum if_type if_typename_to_iftype(const char *if_typename)
	{
	int i;

	for (i = 0; i < IF_TYPE_COUNT; i++) {
	if (if_typename_str[i] &&
	!strcmp(if_typename, if_typename_str[i]))
	return i;
	}

	return IF_TYPE_UNKNOWN;
	}

	static enum uclass_id if_type_to_uclass_id(enum if_type if_type)
	{
	return if_type_uclass_id[if_type];
	}

	const char *blk_get_if_type_name(enum if_type if_type)
	{
	return if_typename_str[if_type];
	}

	struct blk_desc *blk_get_devnum_by_type(enum if_type if_type, int devnum)
	{
	struct blk_desc *desc;
	struct udevice *dev;
	int ret;

	ret = blk_get_device(if_type, devnum, &dev);
	if (ret)
	return NULL;
	desc = dev_get_uclass_platdata(dev);

	return desc;
	}

	/*
	* This function is complicated with driver model. We look up the interface
	* name in a local table. This gives us an interface type which we can match
	* against the uclass of the block device's parent.
	*/
	struct blk_desc blk_get_devnum_by_typename(const char if_typename, int devnum)
	{
	enum uclass_id uclass_id;
	enum if_type if_type;
	struct udevice *dev;
	struct uclass *uc;
	int ret;

	if_type = if_typename_to_iftype(if_typename);
	if (if_type == IF_TYPE_UNKNOWN) {
	debug("%s: Unknown interface type '%s'\n", __func__,
	if_typename);
	return NULL;
	}
	uclass_id = if_type_to_uclass_id(if_type);
	if (uclass_id == UCLASS_INVALID) {
	debug("%s: Unknown uclass for interface type'\n",
	if_typename_str[if_type]);
	return NULL;
	}

	ret = uclass_get(UCLASS_BLK, &uc);
	if (ret)
	return NULL;
	uclass_foreach_dev(dev, uc) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	debug("%s: if_type=%d, devnum=%d: %s, %d, %d\n", __func__,
	if_type, devnum, dev->name, desc->if_type, desc->devnum);
	if (desc->devnum != devnum)
	continue;

	/* Find out the parent device uclass */
	if (device_get_uclass_id(dev->parent) != uclass_id) {
	debug("%s: parent uclass %d, this dev %d\n", __func__,
	device_get_uclass_id(dev->parent), uclass_id);
	continue;
	}

	if (device_probe(dev))
	return NULL;

	debug("%s: Device desc %p\n", __func__, desc);
	return desc;
	}
	debug("%s: No device found\n", __func__);

	return NULL;
	}

	/**
	* blk_get_by_device() - Get the block device descriptor for the given device
	* @dev: Instance of a storage device
	*
	* Return: With block device descriptor on success , NULL if there is no such
	* block device.
	*/
	struct blk_desc blk_get_by_device(struct udevice dev)
	{
	struct udevice *child_dev;

	device_foreach_child(child_dev, dev) {
	if (device_get_uclass_id(child_dev) != UCLASS_BLK)
	continue;

	return dev_get_uclass_platdata(child_dev);
	}

	debug("%s: No block device found\n", __func__);

	return NULL;
	}

	/**
	* get_desc() - Get the block device descriptor for the given device number
	*
	* @if_type: Interface type
	* @devnum: Device number (0 = first)
	* @descp: Returns block device descriptor on success
	* @return 0 on success, -ENODEV if there is no such device and no device
	* with a higher device number, -ENOENT if there is no such device but there
	* is one with a higher number, or other -ve on other error.
	*/
	static int get_desc(enum if_type if_type, int devnum, struct blk_desc **descp)
	{
	bool found_more = false;
	struct udevice *dev;
	struct uclass *uc;
	int ret;

	*descp = NULL;
	ret = uclass_get(UCLASS_BLK, &uc);
	if (ret)
	return ret;
	uclass_foreach_dev(dev, uc) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	debug("%s: if_type=%d, devnum=%d: %s, %d, %d\n", __func__,
	if_type, devnum, dev->name, desc->if_type, desc->devnum);
	if (desc->if_type == if_type) {
	if (desc->devnum == devnum) {
	ret = device_probe(dev);
	if (ret)
	return ret;

	*descp = desc;
	return 0;
	} else if (desc->devnum > devnum) {
	found_more = true;
	}
	}
	}

	return found_more ? -ENOENT : -ENODEV;
	}

	int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart)
	{
	struct udevice *dev;
	int ret;

	ret = blk_get_device(if_type, devnum, &dev);
	if (ret)
	return ret;

	return blk_select_hwpart(dev, hwpart);
	}

	int blk_list_part(enum if_type if_type)
	{
	struct blk_desc *desc;
	int devnum, ok;
	int ret;

	for (ok = 0, devnum = 0;; ++devnum) {
	ret = get_desc(if_type, devnum, &desc);
	if (ret == -ENODEV)
	break;
	else if (ret)
	continue;
	if (desc->part_type != PART_TYPE_UNKNOWN) {
	++ok;
	if (devnum)
	putc('\n');
	part_print(desc);
	}
	}
	if (!ok)
	return -ENODEV;

	return 0;
	}

	int blk_print_part_devnum(enum if_type if_type, int devnum)
	{
	struct blk_desc *desc;
	int ret;

	ret = get_desc(if_type, devnum, &desc);
	if (ret)
	return ret;
	if (desc->type == DEV_TYPE_UNKNOWN)
	return -ENOENT;
	part_print(desc);

	return 0;
	}

	void blk_list_devices(enum if_type if_type)
	{
	struct blk_desc *desc;
	int ret;
	int i;

	for (i = 0;; ++i) {
	ret = get_desc(if_type, i, &desc);
	if (ret == -ENODEV)
	break;
	else if (ret)
	continue;
	if (desc->type == DEV_TYPE_UNKNOWN)
	continue; /* list only known devices */
	printf("Device %d: ", i);
	dev_print(desc);
	}
	}

	int blk_print_device_num(enum if_type if_type, int devnum)
	{
	struct blk_desc *desc;
	int ret;

	ret = get_desc(if_type, devnum, &desc);
	if (ret)
	return ret;
	printf("\nIDE device %d: ", devnum);
	dev_print(desc);

	return 0;
	}

	int blk_show_device(enum if_type if_type, int devnum)
	{
	struct blk_desc *desc;
	int ret;

	printf("\nDevice %d: ", devnum);
	ret = get_desc(if_type, devnum, &desc);
	if (ret == -ENODEV \|\| ret == -ENOENT) {
	printf("unknown device\n");
	return -ENODEV;
	}
	if (ret)
	return ret;
	dev_print(desc);

	if (desc->type == DEV_TYPE_UNKNOWN)
	return -ENOENT;

	return 0;
	}

	ulong blk_read_devnum(enum if_type if_type, int devnum, lbaint_t start,
	lbaint_t blkcnt, void *buffer)
	{
	struct blk_desc *desc;
	ulong n;
	int ret;

	ret = get_desc(if_type, devnum, &desc);
	if (ret)
	return ret;
	n = blk_dread(desc, start, blkcnt, buffer);
	if (IS_ERR_VALUE(n))
	return n;

	return n;
	}

	ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
	lbaint_t blkcnt, const void *buffer)
	{
	struct blk_desc *desc;
	int ret;

	ret = get_desc(if_type, devnum, &desc);
	if (ret)
	return ret;
	return blk_dwrite(desc, start, blkcnt, buffer);
	}

	int blk_select_hwpart(struct udevice *dev, int hwpart)
	{
	const struct blk_ops *ops = blk_get_ops(dev);

	if (!ops)
	return -ENOSYS;
	if (!ops->select_hwpart)
	return 0;

	return ops->select_hwpart(dev, hwpart);
	}

	int blk_dselect_hwpart(struct blk_desc *desc, int hwpart)
	{
	return blk_select_hwpart(desc->bdev, hwpart);
	}

	int blk_first_device(int if_type, struct udevice **devp)
	{
	struct blk_desc *desc;
	int ret;

	ret = uclass_find_first_device(UCLASS_BLK, devp);
	if (ret)
	return ret;
	if (!*devp)
	return -ENODEV;
	do {
	desc = dev_get_uclass_platdata(*devp);
	if (desc->if_type == if_type)
	return 0;
	ret = uclass_find_next_device(devp);
	if (ret)
	return ret;
	} while (*devp);

	return -ENODEV;
	}

	int blk_next_device(struct udevice **devp)
	{
	struct blk_desc *desc;
	int ret, if_type;

	desc = dev_get_uclass_platdata(*devp);
	if_type = desc->if_type;
	do {
	ret = uclass_find_next_device(devp);
	if (ret)
	return ret;
	if (!*devp)
	return -ENODEV;
	desc = dev_get_uclass_platdata(*devp);
	if (desc->if_type == if_type)
	return 0;
	} while (1);
	}

	int blk_find_device(int if_type, int devnum, struct udevice **devp)
	{
	struct uclass *uc;
	struct udevice *dev;
	int ret;

	ret = uclass_get(UCLASS_BLK, &uc);
	if (ret)
	return ret;
	uclass_foreach_dev(dev, uc) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	debug("%s: if_type=%d, devnum=%d: %s, %d, %d\n", __func__,
	if_type, devnum, dev->name, desc->if_type, desc->devnum);
	if (desc->if_type == if_type && desc->devnum == devnum) {
	*devp = dev;
	return 0;
	}
	}

	return -ENODEV;
	}

	int blk_get_device(int if_type, int devnum, struct udevice **devp)
	{
	int ret;

	ret = blk_find_device(if_type, devnum, devp);
	if (ret)
	return ret;

	return device_probe(*devp);
	}

	unsigned long blk_dread(struct blk_desc *block_dev, lbaint_t start,
	lbaint_t blkcnt, void *buffer)
	{
	struct udevice *dev = block_dev->bdev;
	const struct blk_ops *ops = blk_get_ops(dev);
	ulong blks_read;

	if (!ops->read)
	return -ENOSYS;

	if (blkcache_read(block_dev->if_type, block_dev->devnum,
	start, blkcnt, block_dev->blksz, buffer))
	return blkcnt;
	blks_read = ops->read(dev, start, blkcnt, buffer);
	if (blks_read == blkcnt)
	blkcache_fill(block_dev->if_type, block_dev->devnum,
	start, blkcnt, block_dev->blksz, buffer);

	return blks_read;
	}

	unsigned long blk_dwrite(struct blk_desc *block_dev, lbaint_t start,
	lbaint_t blkcnt, const void *buffer)
	{
	struct udevice *dev = block_dev->bdev;
	const struct blk_ops *ops = blk_get_ops(dev);

	if (!ops->write)
	return -ENOSYS;

	blkcache_invalidate(block_dev->if_type, block_dev->devnum);
	return ops->write(dev, start, blkcnt, buffer);
	}

	unsigned long blk_derase(struct blk_desc *block_dev, lbaint_t start,
	lbaint_t blkcnt)
	{
	struct udevice *dev = block_dev->bdev;
	const struct blk_ops *ops = blk_get_ops(dev);

	if (!ops->erase)
	return -ENOSYS;

	blkcache_invalidate(block_dev->if_type, block_dev->devnum);
	return ops->erase(dev, start, blkcnt);
	}

	int blk_get_from_parent(struct udevice parent, struct udevice *devp)
	{
	struct udevice *dev;
	enum uclass_id id;
	int ret;

	device_find_first_child(parent, &dev);
	if (!dev) {
	debug("%s: No block device found for parent '%s'\n", __func__,
	parent->name);
	return -ENODEV;
	}
	id = device_get_uclass_id(dev);
	if (id != UCLASS_BLK) {
	debug("%s: Incorrect uclass %s for block device '%s'\n",
	__func__, uclass_get_name(id), dev->name);
	return -ENOTBLK;
	}
	ret = device_probe(dev);
	if (ret)
	return ret;
	*devp = dev;

	return 0;
	}

	int blk_find_max_devnum(enum if_type if_type)
	{
	struct udevice *dev;
	int max_devnum = -ENODEV;
	struct uclass *uc;
	int ret;

	ret = uclass_get(UCLASS_BLK, &uc);
	if (ret)
	return ret;
	uclass_foreach_dev(dev, uc) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	if (desc->if_type == if_type && desc->devnum > max_devnum)
	max_devnum = desc->devnum;
	}

	return max_devnum;
	}

	int blk_next_free_devnum(enum if_type if_type)
	{
	int ret;

	ret = blk_find_max_devnum(if_type);
	if (ret == -ENODEV)
	return 0;
	if (ret < 0)
	return ret;

	return ret + 1;
	}

	static int blk_claim_devnum(enum if_type if_type, int devnum)
	{
	struct udevice *dev;
	struct uclass *uc;
	int ret;

	ret = uclass_get(UCLASS_BLK, &uc);
	if (ret)
	return ret;
	uclass_foreach_dev(dev, uc) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	if (desc->if_type == if_type && desc->devnum == devnum) {
	int next = blk_next_free_devnum(if_type);

	if (next < 0)
	return next;
	desc->devnum = next;
	return 0;
	}
	}

	return -ENOENT;
	}

	int blk_create_device(struct udevice parent, const char drv_name,
	const char *name, int if_type, int devnum, int blksz,
	lbaint_t lba, struct udevice **devp)
	{
	struct blk_desc *desc;
	struct udevice *dev;
	int ret;

	if (devnum == -1) {
	devnum = blk_next_free_devnum(if_type);
	} else {
	ret = blk_claim_devnum(if_type, devnum);
	if (ret < 0 && ret != -ENOENT)
	return ret;
	}
	if (devnum < 0)
	return devnum;
	ret = device_bind_driver(parent, drv_name, name, &dev);
	if (ret)
	return ret;
	desc = dev_get_uclass_platdata(dev);
	desc->if_type = if_type;
	desc->blksz = blksz;
	desc->log2blksz = LOG2(desc->blksz);
	desc->lba = lba;
	desc->part_type = PART_TYPE_UNKNOWN;
	desc->bdev = dev;
	desc->devnum = devnum;
	*devp = dev;

	return 0;
	}

	int blk_create_devicef(struct udevice parent, const char drv_name,
	const char *name, int if_type, int devnum, int blksz,
	lbaint_t lba, struct udevice **devp)
	{
	char dev_name[30], *str;
	int ret;

	snprintf(dev_name, sizeof(dev_name), "%s.%s", parent->name, name);
	str = strdup(dev_name);
	if (!str)
	return -ENOMEM;

	ret = blk_create_device(parent, drv_name, str, if_type, devnum,
	blksz, lba, devp);
	if (ret) {
	free(str);
	return ret;
	}
	device_set_name_alloced(*devp);

	return 0;
	}

	int blk_unbind_all(int if_type)
	{
	struct uclass *uc;
	struct udevice dev, next;
	int ret;

	ret = uclass_get(UCLASS_BLK, &uc);
	if (ret)
	return ret;
	uclass_foreach_dev_safe(dev, next, uc) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	if (desc->if_type == if_type) {
	ret = device_remove(dev, DM_REMOVE_NORMAL);
	if (ret)
	return ret;
	ret = device_unbind(dev);
	if (ret)
	return ret;
	}
	}

	return 0;
	}

	static int blk_post_probe(struct udevice *dev)
	{
	if (IS_ENABLED(CONFIG_PARTITIONS) &&
	IS_ENABLED(CONFIG_HAVE_BLOCK_DEVICE)) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);

	part_init(desc);
	}

	return 0;
	}

	UCLASS_DRIVER(blk) = {
	.id = UCLASS_BLK,
	.name = "blk",
	.post_probe = blk_post_probe,
	.per_device_platdata_auto_alloc_size = sizeof(struct blk_desc),
	};