lib/efi_loader/efi_disk.c - filogic/uboot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  *  EFI application disk support
  *
  *  Copyright (c) 2016 Alexander Graf
  */

 #include <common.h>
 #include <blk.h>
 #include <dm.h>
 #include <efi_loader.h>
 #include <part.h>
 #include <malloc.h>

 const efi_guid_t efi_block_io_guid = EFI_BLOCK_IO_PROTOCOL_GUID;

 /**
  * struct efi_disk_obj - EFI disk object
  *
  * @header:	EFI object header
  * @ops:	EFI disk I/O protocol interface
  * @ifname:	interface name for block device
  * @dev_index:	device index of block device
  * @media:	block I/O media information
  * @dp:		device path to the block device
  * @part:	partition
  * @volume:	simple file system protocol of the partition
  * @offset:	offset into disk for simple partition
  * @desc:	internal block device descriptor
  */
 struct efi_disk_obj {
 	struct efi_object header;
 	struct efi_block_io ops;
 	const char *ifname;
 	int dev_index;
 	struct efi_block_io_media media;
 	struct efi_device_path *dp;
 	unsigned int part;
 	struct efi_simple_file_system_protocol *volume;
 	lbaint_t offset;
 	struct blk_desc *desc;
 };

 static efi_status_t EFIAPI efi_disk_reset(struct efi_block_io *this,
 			char extended_verification)
 {
 	EFI_ENTRY("%p, %x", this, extended_verification);
 	return EFI_EXIT(EFI_DEVICE_ERROR);
 }

 enum efi_disk_direction {
 	EFI_DISK_READ,
 	EFI_DISK_WRITE,
 };

 static efi_status_t efi_disk_rw_blocks(struct efi_block_io *this,
 			u32 media_id, u64 lba, unsigned long buffer_size,
 			void *buffer, enum efi_disk_direction direction)
 {
 	struct efi_disk_obj *diskobj;
 	struct blk_desc *desc;
 	int blksz;
 	int blocks;
 	unsigned long n;

 	diskobj = container_of(this, struct efi_disk_obj, ops);
 	desc = (struct blk_desc *) diskobj->desc;
 	blksz = desc->blksz;
 	blocks = buffer_size / blksz;
 	lba += diskobj->offset;

 	debug("EFI: %s:%d blocks=%x lba=%llx blksz=%x dir=%d\n", __func__,
 	      __LINE__, blocks, lba, blksz, direction);

 	/* We only support full block access */
 	if (buffer_size & (blksz - 1))
 		return EFI_BAD_BUFFER_SIZE;

 	if (direction == EFI_DISK_READ)
 		n = blk_dread(desc, lba, blocks, buffer);
 	else
 		n = blk_dwrite(desc, lba, blocks, buffer);

 	/* We don't do interrupts, so check for timers cooperatively */
 	efi_timer_check();

 	debug("EFI: %s:%d n=%lx blocks=%x\n", __func__, __LINE__, n, blocks);

 	if (n != blocks)
 		return EFI_DEVICE_ERROR;

 	return EFI_SUCCESS;
 }

 static efi_status_t EFIAPI efi_disk_read_blocks(struct efi_block_io *this,
 			u32 media_id, u64 lba, efi_uintn_t buffer_size,
 			void *buffer)
 {
 	void *real_buffer = buffer;
 	efi_status_t r;

 	if (!this)
 		return EFI_INVALID_PARAMETER;
 	/* TODO: check for media changes */
 	if (media_id != this->media->media_id)
 		return EFI_MEDIA_CHANGED;
 	if (!this->media->media_present)
 		return EFI_NO_MEDIA;
 	/* media->io_align is a power of 2 */
 	if ((uintptr_t)buffer & (this->media->io_align - 1))
 		return EFI_INVALID_PARAMETER;
 	if (lba * this->media->block_size + buffer_size >
 	    this->media->last_block * this->media->block_size)
 		return EFI_INVALID_PARAMETER;

 #ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER
 	if (buffer_size > EFI_LOADER_BOUNCE_BUFFER_SIZE) {
 		r = efi_disk_read_blocks(this, media_id, lba,
 			EFI_LOADER_BOUNCE_BUFFER_SIZE, buffer);
 		if (r != EFI_SUCCESS)
 			return r;
 		return efi_disk_read_blocks(this, media_id, lba +
 			EFI_LOADER_BOUNCE_BUFFER_SIZE / this->media->block_size,
 			buffer_size - EFI_LOADER_BOUNCE_BUFFER_SIZE,
 			buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE);
 	}

 	real_buffer = efi_bounce_buffer;
 #endif

 	EFI_ENTRY("%p, %x, %llx, %zx, %p", this, media_id, lba,
 		  buffer_size, buffer);

 	r = efi_disk_rw_blocks(this, media_id, lba, buffer_size, real_buffer,
 			       EFI_DISK_READ);

 	/* Copy from bounce buffer to real buffer if necessary */
 	if ((r == EFI_SUCCESS) && (real_buffer != buffer))
 		memcpy(buffer, real_buffer, buffer_size);

 	return EFI_EXIT(r);
 }

 static efi_status_t EFIAPI efi_disk_write_blocks(struct efi_block_io *this,
 			u32 media_id, u64 lba, efi_uintn_t buffer_size,
 			void *buffer)
 {
 	void *real_buffer = buffer;
 	efi_status_t r;

 	if (!this)
 		return EFI_INVALID_PARAMETER;
 	if (this->media->read_only)
 		return EFI_WRITE_PROTECTED;
 	/* TODO: check for media changes */
 	if (media_id != this->media->media_id)
 		return EFI_MEDIA_CHANGED;
 	if (!this->media->media_present)
 		return EFI_NO_MEDIA;
 	/* media->io_align is a power of 2 */
 	if ((uintptr_t)buffer & (this->media->io_align - 1))
 		return EFI_INVALID_PARAMETER;
 	if (lba * this->media->block_size + buffer_size >
 	    this->media->last_block * this->media->block_size)
 		return EFI_INVALID_PARAMETER;

 #ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER
 	if (buffer_size > EFI_LOADER_BOUNCE_BUFFER_SIZE) {
 		r = efi_disk_write_blocks(this, media_id, lba,
 			EFI_LOADER_BOUNCE_BUFFER_SIZE, buffer);
 		if (r != EFI_SUCCESS)
 			return r;
 		return efi_disk_write_blocks(this, media_id, lba +
 			EFI_LOADER_BOUNCE_BUFFER_SIZE / this->media->block_size,
 			buffer_size - EFI_LOADER_BOUNCE_BUFFER_SIZE,
 			buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE);
 	}

 	real_buffer = efi_bounce_buffer;
 #endif

 	EFI_ENTRY("%p, %x, %llx, %zx, %p", this, media_id, lba,
 		  buffer_size, buffer);

 	/* Populate bounce buffer if necessary */
 	if (real_buffer != buffer)
 		memcpy(real_buffer, buffer, buffer_size);

 	r = efi_disk_rw_blocks(this, media_id, lba, buffer_size, real_buffer,
 			       EFI_DISK_WRITE);

 	return EFI_EXIT(r);
 }

 static efi_status_t EFIAPI efi_disk_flush_blocks(struct efi_block_io *this)
 {
 	/* We always write synchronously */
 	EFI_ENTRY("%p", this);
 	return EFI_EXIT(EFI_SUCCESS);
 }

 static const struct efi_block_io block_io_disk_template = {
 	.reset = &efi_disk_reset,
 	.read_blocks = &efi_disk_read_blocks,
 	.write_blocks = &efi_disk_write_blocks,
 	.flush_blocks = &efi_disk_flush_blocks,
 };

 /*
  * Get the simple file system protocol for a file device path.
  *
  * The full path provided is split into device part and into a file
  * part. The device part is used to find the handle on which the
  * simple file system protocol is installed.
  *
  * @full_path	device path including device and file
  * @return	simple file system protocol
  */
 struct efi_simple_file_system_protocol *
 efi_fs_from_path(struct efi_device_path *full_path)
 {
 	struct efi_object *efiobj;
 	struct efi_handler *handler;
 	struct efi_device_path *device_path;
 	struct efi_device_path *file_path;
 	efi_status_t ret;

 	/* Split the path into a device part and a file part */
 	ret = efi_dp_split_file_path(full_path, &device_path, &file_path);
 	if (ret != EFI_SUCCESS)
 		return NULL;
 	efi_free_pool(file_path);

 	/* Get the EFI object for the partition */
 	efiobj = efi_dp_find_obj(device_path, NULL);
 	efi_free_pool(device_path);
 	if (!efiobj)
 		return NULL;

 	/* Find the simple file system protocol */
 	ret = efi_search_protocol(efiobj, &efi_simple_file_system_protocol_guid,
 				  &handler);
 	if (ret != EFI_SUCCESS)
 		return NULL;

 	/* Return the simple file system protocol for the partition */
 	return handler->protocol_interface;
 }

 /*
  * Create a handle for a partition or disk
  *
  * @parent	parent handle
  * @dp_parent	parent device path
  * @if_typename interface name for block device
  * @desc	internal block device
  * @dev_index   device index for block device
  * @offset	offset into disk for simple partitions
  * @return	disk object
  */
 static efi_status_t efi_disk_add_dev(
 				efi_handle_t parent,
 				struct efi_device_path *dp_parent,
 				const char *if_typename,
 				struct blk_desc *desc,
 				int dev_index,
 				lbaint_t offset,
 				unsigned int part,
 				struct efi_disk_obj **disk)
 {
 	struct efi_disk_obj *diskobj;
 	efi_status_t ret;

 	/* Don't add empty devices */
 	if (!desc->lba)
 		return EFI_NOT_READY;

 	diskobj = calloc(1, sizeof(*diskobj));
 	if (!diskobj)
 		return EFI_OUT_OF_RESOURCES;

 	/* Hook up to the device list */
 	efi_add_handle(&diskobj->header);

 	/* Fill in object data */
 	if (part) {
 		struct efi_device_path *node = efi_dp_part_node(desc, part);

 		diskobj->dp = efi_dp_append_node(dp_parent, node);
 		efi_free_pool(node);
 	} else {
 		diskobj->dp = efi_dp_from_part(desc, part);
 	}
 	diskobj->part = part;
 	ret = efi_add_protocol(&diskobj->header, &efi_block_io_guid,
 			       &diskobj->ops);
 	if (ret != EFI_SUCCESS)
 		return ret;
 	ret = efi_add_protocol(&diskobj->header, &efi_guid_device_path,
 			       diskobj->dp);
 	if (ret != EFI_SUCCESS)
 		return ret;
 	if (part >= 1) {
 		diskobj->volume = efi_simple_file_system(desc, part,
 							 diskobj->dp);
 		ret = efi_add_protocol(&diskobj->header,
 				       &efi_simple_file_system_protocol_guid,
 				       diskobj->volume);
 		if (ret != EFI_SUCCESS)
 			return ret;
 	}
 	diskobj->ops = block_io_disk_template;
 	diskobj->ifname = if_typename;
 	diskobj->dev_index = dev_index;
 	diskobj->offset = offset;
 	diskobj->desc = desc;

 	/* Fill in EFI IO Media info (for read/write callbacks) */
 	diskobj->media.removable_media = desc->removable;
 	diskobj->media.media_present = 1;
 	/*
 	 * MediaID is just an arbitrary counter.
 	 * We have to change it if the medium is removed or changed.
 	 */
 	diskobj->media.media_id = 1;
 	diskobj->media.block_size = desc->blksz;
 	diskobj->media.io_align = desc->blksz;
 	diskobj->media.last_block = desc->lba - offset;
 	if (part != 0)
 		diskobj->media.logical_partition = 1;
 	diskobj->ops.media = &diskobj->media;
 	if (disk)
 		*disk = diskobj;
 	return EFI_SUCCESS;
 }

 /*
  * Create handles and protocols for the partitions of a block device
  *
  * @parent		handle of the parent disk
  * @blk_desc		block device
  * @if_typename		interface type
  * @diskid		device number
  * @pdevname		device name
  * @return		number of partitions created
  */
 int efi_disk_create_partitions(efi_handle_t parent, struct blk_desc *desc,
 			       const char *if_typename, int diskid,
 			       const char *pdevname)
 {
 	int disks = 0;
 	char devname[32] = { 0 }; /* dp->str is u16[32] long */
 	disk_partition_t info;
 	int part;
 	struct efi_device_path *dp = NULL;
 	efi_status_t ret;
 	struct efi_handler *handler;

 	/* Get the device path of the parent */
 	ret = efi_search_protocol(parent, &efi_guid_device_path, &handler);
 	if (ret == EFI_SUCCESS)
 		dp = handler->protocol_interface;

 	/* Add devices for each partition */
 	for (part = 1; part <= MAX_SEARCH_PARTITIONS; part++) {
 		if (part_get_info(desc, part, &info))
 			continue;
 		snprintf(devname, sizeof(devname), "%s:%d", pdevname,
 			 part);
 		ret = efi_disk_add_dev(parent, dp, if_typename, desc, diskid,
 				       info.start, part, NULL);
 		if (ret != EFI_SUCCESS) {
 			printf("Adding partition %s failed\n", pdevname);
 			continue;
 		}
 		disks++;
 	}

 	return disks;
 }

 /*
  * U-Boot doesn't have a list of all online disk devices. So when running our
  * EFI payload, we scan through all of the potentially available ones and
  * store them in our object pool.
  *
  * TODO(sjg@chromium.org): Actually with CONFIG_BLK, U-Boot does have this.
  * Consider converting the code to look up devices as needed. The EFI device
  * could be a child of the UCLASS_BLK block device, perhaps.
  *
  * This gets called from do_bootefi_exec().
  */
 efi_status_t efi_disk_register(void)
 {
 	struct efi_disk_obj *disk;
 	int disks = 0;
 	efi_status_t ret;
 #ifdef CONFIG_BLK
 	struct udevice *dev;

 	for (uclass_first_device_check(UCLASS_BLK, &dev); dev;
 	     uclass_next_device_check(&dev)) {
 		struct blk_desc *desc = dev_get_uclass_platdata(dev);
 		const char *if_typename = blk_get_if_type_name(desc->if_type);

 		/* Add block device for the full device */
 		printf("Scanning disk %s...\n", dev->name);
 		ret = efi_disk_add_dev(NULL, NULL, if_typename,
 					desc, desc->devnum, 0, 0, &disk);
 		if (ret == EFI_NOT_READY) {
 			printf("Disk %s not ready\n", dev->name);
 			continue;
 		}
 		if (ret) {
 			printf("ERROR: failure to add disk device %s, r = %lu\n",
 			       dev->name, ret & ~EFI_ERROR_MASK);
 			return ret;
 		}
 		disks++;

 		/* Partitions show up as block devices in EFI */
 		disks += efi_disk_create_partitions(
 					&disk->header, desc, if_typename,
 					desc->devnum, dev->name);
 	}
 #else
 	int i, if_type;

 	/* Search for all available disk devices */
 	for (if_type = 0; if_type < IF_TYPE_COUNT; if_type++) {
 		const struct blk_driver *cur_drvr;
 		const char *if_typename;

 		cur_drvr = blk_driver_lookup_type(if_type);
 		if (!cur_drvr)
 			continue;

 		if_typename = cur_drvr->if_typename;
 		printf("Scanning disks on %s...\n", if_typename);
 		for (i = 0; i < 4; i++) {
 			struct blk_desc *desc;
 			char devname[32] = { 0 }; /* dp->str is u16[32] long */

 			desc = blk_get_devnum_by_type(if_type, i);
 			if (!desc)
 				continue;
 			if (desc->type == DEV_TYPE_UNKNOWN)
 				continue;

 			snprintf(devname, sizeof(devname), "%s%d",
 				 if_typename, i);

 			/* Add block device for the full device */
 			ret = efi_disk_add_dev(NULL, NULL, if_typename, desc,
 					       i, 0, 0, &disk);
 			if (ret == EFI_NOT_READY) {
 				printf("Disk %s not ready\n", devname);
 				continue;
 			}
 			if (ret) {
 				printf("ERROR: failure to add disk device %s, r = %lu\n",
 				       devname, ret & ~EFI_ERROR_MASK);
 				return ret;
 			}
 			disks++;

 			/* Partitions show up as block devices in EFI */
 			disks += efi_disk_create_partitions
 						(&disk->header, desc,
 						 if_typename, i, devname);
 		}
 	}
 #endif
 	printf("Found %d disks\n", disks);

 	return EFI_SUCCESS;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* EFI application disk support
	*
	* Copyright (c) 2016 Alexander Graf
	*/

	#include <common.h>
	#include <blk.h>
	#include <dm.h>
	#include <efi_loader.h>
	#include <part.h>
	#include <malloc.h>

	const efi_guid_t efi_block_io_guid = EFI_BLOCK_IO_PROTOCOL_GUID;

	/**
	* struct efi_disk_obj - EFI disk object
	*
	* @header: EFI object header
	* @ops: EFI disk I/O protocol interface
	* @ifname: interface name for block device
	* @dev_index: device index of block device
	* @media: block I/O media information
	* @dp: device path to the block device
	* @part: partition
	* @volume: simple file system protocol of the partition
	* @offset: offset into disk for simple partition
	* @desc: internal block device descriptor
	*/
	struct efi_disk_obj {
	struct efi_object header;
	struct efi_block_io ops;
	const char *ifname;
	int dev_index;
	struct efi_block_io_media media;
	struct efi_device_path *dp;
	unsigned int part;
	struct efi_simple_file_system_protocol *volume;
	lbaint_t offset;
	struct blk_desc *desc;
	};

	static efi_status_t EFIAPI efi_disk_reset(struct efi_block_io *this,
	char extended_verification)
	{
	EFI_ENTRY("%p, %x", this, extended_verification);
	return EFI_EXIT(EFI_DEVICE_ERROR);
	}

	enum efi_disk_direction {
	EFI_DISK_READ,
	EFI_DISK_WRITE,
	};

	static efi_status_t efi_disk_rw_blocks(struct efi_block_io *this,
	u32 media_id, u64 lba, unsigned long buffer_size,
	void *buffer, enum efi_disk_direction direction)
	{
	struct efi_disk_obj *diskobj;
	struct blk_desc *desc;
	int blksz;
	int blocks;
	unsigned long n;

	diskobj = container_of(this, struct efi_disk_obj, ops);
	desc = (struct blk_desc *) diskobj->desc;
	blksz = desc->blksz;
	blocks = buffer_size / blksz;
	lba += diskobj->offset;

	debug("EFI: %s:%d blocks=%x lba=%llx blksz=%x dir=%d\n", __func__,
	__LINE__, blocks, lba, blksz, direction);

	/* We only support full block access */
	if (buffer_size & (blksz - 1))
	return EFI_BAD_BUFFER_SIZE;

	if (direction == EFI_DISK_READ)
	n = blk_dread(desc, lba, blocks, buffer);
	else
	n = blk_dwrite(desc, lba, blocks, buffer);

	/* We don't do interrupts, so check for timers cooperatively */
	efi_timer_check();

	debug("EFI: %s:%d n=%lx blocks=%x\n", __func__, __LINE__, n, blocks);

	if (n != blocks)
	return EFI_DEVICE_ERROR;

	return EFI_SUCCESS;
	}

	static efi_status_t EFIAPI efi_disk_read_blocks(struct efi_block_io *this,
	u32 media_id, u64 lba, efi_uintn_t buffer_size,
	void *buffer)
	{
	void *real_buffer = buffer;
	efi_status_t r;

	if (!this)
	return EFI_INVALID_PARAMETER;
	/* TODO: check for media changes */
	if (media_id != this->media->media_id)
	return EFI_MEDIA_CHANGED;
	if (!this->media->media_present)
	return EFI_NO_MEDIA;
	/* media->io_align is a power of 2 */
	if ((uintptr_t)buffer & (this->media->io_align - 1))
	return EFI_INVALID_PARAMETER;
	if (lba * this->media->block_size + buffer_size >
	this->media->last_block * this->media->block_size)
	return EFI_INVALID_PARAMETER;

	#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER
	if (buffer_size > EFI_LOADER_BOUNCE_BUFFER_SIZE) {
	r = efi_disk_read_blocks(this, media_id, lba,
	EFI_LOADER_BOUNCE_BUFFER_SIZE, buffer);
	if (r != EFI_SUCCESS)
	return r;
	return efi_disk_read_blocks(this, media_id, lba +
	EFI_LOADER_BOUNCE_BUFFER_SIZE / this->media->block_size,
	buffer_size - EFI_LOADER_BOUNCE_BUFFER_SIZE,
	buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE);
	}

	real_buffer = efi_bounce_buffer;
	#endif

	EFI_ENTRY("%p, %x, %llx, %zx, %p", this, media_id, lba,
	buffer_size, buffer);

	r = efi_disk_rw_blocks(this, media_id, lba, buffer_size, real_buffer,
	EFI_DISK_READ);

	/* Copy from bounce buffer to real buffer if necessary */
	if ((r == EFI_SUCCESS) && (real_buffer != buffer))
	memcpy(buffer, real_buffer, buffer_size);

	return EFI_EXIT(r);
	}

	static efi_status_t EFIAPI efi_disk_write_blocks(struct efi_block_io *this,
	u32 media_id, u64 lba, efi_uintn_t buffer_size,
	void *buffer)
	{
	void *real_buffer = buffer;
	efi_status_t r;

	if (!this)
	return EFI_INVALID_PARAMETER;
	if (this->media->read_only)
	return EFI_WRITE_PROTECTED;
	/* TODO: check for media changes */
	if (media_id != this->media->media_id)
	return EFI_MEDIA_CHANGED;
	if (!this->media->media_present)
	return EFI_NO_MEDIA;
	/* media->io_align is a power of 2 */
	if ((uintptr_t)buffer & (this->media->io_align - 1))
	return EFI_INVALID_PARAMETER;
	if (lba * this->media->block_size + buffer_size >
	this->media->last_block * this->media->block_size)
	return EFI_INVALID_PARAMETER;

	#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER
	if (buffer_size > EFI_LOADER_BOUNCE_BUFFER_SIZE) {
	r = efi_disk_write_blocks(this, media_id, lba,
	EFI_LOADER_BOUNCE_BUFFER_SIZE, buffer);
	if (r != EFI_SUCCESS)
	return r;
	return efi_disk_write_blocks(this, media_id, lba +
	EFI_LOADER_BOUNCE_BUFFER_SIZE / this->media->block_size,
	buffer_size - EFI_LOADER_BOUNCE_BUFFER_SIZE,
	buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE);
	}

	real_buffer = efi_bounce_buffer;
	#endif

	EFI_ENTRY("%p, %x, %llx, %zx, %p", this, media_id, lba,
	buffer_size, buffer);

	/* Populate bounce buffer if necessary */
	if (real_buffer != buffer)
	memcpy(real_buffer, buffer, buffer_size);

	r = efi_disk_rw_blocks(this, media_id, lba, buffer_size, real_buffer,
	EFI_DISK_WRITE);

	return EFI_EXIT(r);
	}

	static efi_status_t EFIAPI efi_disk_flush_blocks(struct efi_block_io *this)
	{
	/* We always write synchronously */
	EFI_ENTRY("%p", this);
	return EFI_EXIT(EFI_SUCCESS);
	}

	static const struct efi_block_io block_io_disk_template = {
	.reset = &efi_disk_reset,
	.read_blocks = &efi_disk_read_blocks,
	.write_blocks = &efi_disk_write_blocks,
	.flush_blocks = &efi_disk_flush_blocks,
	};

	/*
	* Get the simple file system protocol for a file device path.
	*
	* The full path provided is split into device part and into a file
	* part. The device part is used to find the handle on which the
	* simple file system protocol is installed.
	*
	* @full_path device path including device and file
	* @return simple file system protocol
	*/
	struct efi_simple_file_system_protocol *
	efi_fs_from_path(struct efi_device_path *full_path)
	{
	struct efi_object *efiobj;
	struct efi_handler *handler;
	struct efi_device_path *device_path;
	struct efi_device_path *file_path;
	efi_status_t ret;

	/* Split the path into a device part and a file part */
	ret = efi_dp_split_file_path(full_path, &device_path, &file_path);
	if (ret != EFI_SUCCESS)
	return NULL;
	efi_free_pool(file_path);

	/* Get the EFI object for the partition */
	efiobj = efi_dp_find_obj(device_path, NULL);
	efi_free_pool(device_path);
	if (!efiobj)
	return NULL;

	/* Find the simple file system protocol */
	ret = efi_search_protocol(efiobj, &efi_simple_file_system_protocol_guid,
	&handler);
	if (ret != EFI_SUCCESS)
	return NULL;

	/* Return the simple file system protocol for the partition */
	return handler->protocol_interface;
	}

	/*
	* Create a handle for a partition or disk
	*
	* @parent parent handle
	* @dp_parent parent device path
	* @if_typename interface name for block device
	* @desc internal block device
	* @dev_index device index for block device
	* @offset offset into disk for simple partitions
	* @return disk object
	*/
	static efi_status_t efi_disk_add_dev(
	efi_handle_t parent,
	struct efi_device_path *dp_parent,
	const char *if_typename,
	struct blk_desc *desc,
	int dev_index,
	lbaint_t offset,
	unsigned int part,
	struct efi_disk_obj **disk)
	{
	struct efi_disk_obj *diskobj;
	efi_status_t ret;

	/* Don't add empty devices */
	if (!desc->lba)
	return EFI_NOT_READY;

	diskobj = calloc(1, sizeof(*diskobj));
	if (!diskobj)
	return EFI_OUT_OF_RESOURCES;

	/* Hook up to the device list */
	efi_add_handle(&diskobj->header);

	/* Fill in object data */
	if (part) {
	struct efi_device_path *node = efi_dp_part_node(desc, part);

	diskobj->dp = efi_dp_append_node(dp_parent, node);
	efi_free_pool(node);
	} else {
	diskobj->dp = efi_dp_from_part(desc, part);
	}
	diskobj->part = part;
	ret = efi_add_protocol(&diskobj->header, &efi_block_io_guid,
	&diskobj->ops);
	if (ret != EFI_SUCCESS)
	return ret;
	ret = efi_add_protocol(&diskobj->header, &efi_guid_device_path,
	diskobj->dp);
	if (ret != EFI_SUCCESS)
	return ret;
	if (part >= 1) {
	diskobj->volume = efi_simple_file_system(desc, part,
	diskobj->dp);
	ret = efi_add_protocol(&diskobj->header,
	&efi_simple_file_system_protocol_guid,
	diskobj->volume);
	if (ret != EFI_SUCCESS)
	return ret;
	}
	diskobj->ops = block_io_disk_template;
	diskobj->ifname = if_typename;
	diskobj->dev_index = dev_index;
	diskobj->offset = offset;
	diskobj->desc = desc;

	/* Fill in EFI IO Media info (for read/write callbacks) */
	diskobj->media.removable_media = desc->removable;
	diskobj->media.media_present = 1;
	/*
	* MediaID is just an arbitrary counter.
	* We have to change it if the medium is removed or changed.
	*/
	diskobj->media.media_id = 1;
	diskobj->media.block_size = desc->blksz;
	diskobj->media.io_align = desc->blksz;
	diskobj->media.last_block = desc->lba - offset;
	if (part != 0)
	diskobj->media.logical_partition = 1;
	diskobj->ops.media = &diskobj->media;
	if (disk)
	*disk = diskobj;
	return EFI_SUCCESS;
	}

	/*
	* Create handles and protocols for the partitions of a block device
	*
	* @parent handle of the parent disk
	* @blk_desc block device
	* @if_typename interface type
	* @diskid device number
	* @pdevname device name
	* @return number of partitions created
	*/
	int efi_disk_create_partitions(efi_handle_t parent, struct blk_desc *desc,
	const char *if_typename, int diskid,
	const char *pdevname)
	{
	int disks = 0;
	char devname[32] = { 0 }; /* dp->str is u16[32] long */
	disk_partition_t info;
	int part;
	struct efi_device_path *dp = NULL;
	efi_status_t ret;
	struct efi_handler *handler;

	/* Get the device path of the parent */
	ret = efi_search_protocol(parent, &efi_guid_device_path, &handler);
	if (ret == EFI_SUCCESS)
	dp = handler->protocol_interface;

	/* Add devices for each partition */
	for (part = 1; part <= MAX_SEARCH_PARTITIONS; part++) {
	if (part_get_info(desc, part, &info))
	continue;
	snprintf(devname, sizeof(devname), "%s:%d", pdevname,
	part);
	ret = efi_disk_add_dev(parent, dp, if_typename, desc, diskid,
	info.start, part, NULL);
	if (ret != EFI_SUCCESS) {
	printf("Adding partition %s failed\n", pdevname);
	continue;
	}
	disks++;
	}

	return disks;
	}

	/*
	* U-Boot doesn't have a list of all online disk devices. So when running our
	* EFI payload, we scan through all of the potentially available ones and
	* store them in our object pool.
	*
	* TODO(sjg@chromium.org): Actually with CONFIG_BLK, U-Boot does have this.
	* Consider converting the code to look up devices as needed. The EFI device
	* could be a child of the UCLASS_BLK block device, perhaps.
	*
	* This gets called from do_bootefi_exec().
	*/
	efi_status_t efi_disk_register(void)
	{
	struct efi_disk_obj *disk;
	int disks = 0;
	efi_status_t ret;
	#ifdef CONFIG_BLK
	struct udevice *dev;

	for (uclass_first_device_check(UCLASS_BLK, &dev); dev;
	uclass_next_device_check(&dev)) {
	struct blk_desc *desc = dev_get_uclass_platdata(dev);
	const char *if_typename = blk_get_if_type_name(desc->if_type);

	/* Add block device for the full device */
	printf("Scanning disk %s...\n", dev->name);
	ret = efi_disk_add_dev(NULL, NULL, if_typename,
	desc, desc->devnum, 0, 0, &disk);
	if (ret == EFI_NOT_READY) {
	printf("Disk %s not ready\n", dev->name);
	continue;
	}
	if (ret) {
	printf("ERROR: failure to add disk device %s, r = %lu\n",
	dev->name, ret & ~EFI_ERROR_MASK);
	return ret;
	}
	disks++;

	/* Partitions show up as block devices in EFI */
	disks += efi_disk_create_partitions(
	&disk->header, desc, if_typename,
	desc->devnum, dev->name);
	}
	#else
	int i, if_type;

	/* Search for all available disk devices */
	for (if_type = 0; if_type < IF_TYPE_COUNT; if_type++) {
	const struct blk_driver *cur_drvr;
	const char *if_typename;

	cur_drvr = blk_driver_lookup_type(if_type);
	if (!cur_drvr)
	continue;

	if_typename = cur_drvr->if_typename;
	printf("Scanning disks on %s...\n", if_typename);
	for (i = 0; i < 4; i++) {
	struct blk_desc *desc;
	char devname[32] = { 0 }; /* dp->str is u16[32] long */

	desc = blk_get_devnum_by_type(if_type, i);
	if (!desc)
	continue;
	if (desc->type == DEV_TYPE_UNKNOWN)
	continue;

	snprintf(devname, sizeof(devname), "%s%d",
	if_typename, i);

	/* Add block device for the full device */
	ret = efi_disk_add_dev(NULL, NULL, if_typename, desc,
	i, 0, 0, &disk);
	if (ret == EFI_NOT_READY) {
	printf("Disk %s not ready\n", devname);
	continue;
	}
	if (ret) {
	printf("ERROR: failure to add disk device %s, r = %lu\n",
	devname, ret & ~EFI_ERROR_MASK);
	return ret;
	}
	disks++;

	/* Partitions show up as block devices in EFI */
	disks += efi_disk_create_partitions
	(&disk->header, desc,
	if_typename, i, devname);
	}
	}
	#endif
	printf("Found %d disks\n", disks);

	return EFI_SUCCESS;
	}