1 /* SPDX-License-Identifier: GPL-2.0+ */
3 * (C) Copyright 2000-2004
10 #include <bouncebuf.h>
11 #include <dm/uclass-id.h>
14 #ifdef CONFIG_SYS_64BIT_LBA
15 typedef uint64_t lbaint_t;
16 #define LBAFlength "ll"
18 typedef ulong lbaint_t;
19 #define LBAFlength "l"
21 #define LBAF "%" LBAFlength "x"
22 #define LBAFU "%" LBAFlength "u"
24 #define DEFAULT_BLKSZ 512
28 static inline bool blk_enabled(void)
30 return CONFIG_IS_ENABLED(BLK) || IS_ENABLED(CONFIG_SPL_LEGACY_BLOCK);
33 #define BLK_VEN_SIZE 40
34 #define BLK_PRD_SIZE 20
35 #define BLK_REV_SIZE 8
37 #define PART_FORMAT_PCAT 0x1
38 #define PART_FORMAT_GPT 0x2
41 * Identifies the partition table type (ie. MBR vs GPT GUID) signature
48 SIG_TYPE_COUNT /* Number of signature types */
52 * With driver model (CONFIG_BLK) this is uclass platform data, accessible
53 * with dev_get_uclass_plat(dev)
57 * TODO: With driver model we should be able to use the parent
58 * device's uclass instead.
60 enum uclass_id uclass_id; /* type of the interface */
61 int devnum; /* device number */
62 unsigned char part_type; /* partition type */
63 unsigned char target; /* target SCSI ID */
64 unsigned char lun; /* target LUN */
65 unsigned char hwpart; /* HW partition, e.g. for eMMC */
66 unsigned char type; /* device type */
67 unsigned char removable; /* removable device */
68 /* device can use 48bit addr (ATA/ATAPI v7) */
70 unsigned char atapi; /* Use ATAPI protocol */
71 unsigned char bb; /* Use bounce buffer */
72 lbaint_t lba; /* number of blocks */
73 unsigned long blksz; /* block size */
74 int log2blksz; /* for convenience: log2(blksz) */
75 char vendor[BLK_VEN_SIZE + 1]; /* device vendor string */
76 char product[BLK_PRD_SIZE + 1]; /* device product number */
77 char revision[BLK_REV_SIZE + 1]; /* firmware revision */
78 enum sig_type sig_type; /* Partition table signature type */
80 uint32_t mbr_sig; /* MBR integer signature */
81 efi_guid_t guid_sig; /* GPT GUID Signature */
83 #if CONFIG_IS_ENABLED(BLK)
85 * For now we have a few functions which take struct blk_desc as a
86 * parameter. This field allows them to look up the associated
87 * device. Once these functions are removed we can drop this field.
91 unsigned long (*block_read)(struct blk_desc *block_dev,
95 unsigned long (*block_write)(struct blk_desc *block_dev,
99 unsigned long (*block_erase)(struct blk_desc *block_dev,
102 void *priv; /* driver private struct pointer */
106 #define BLOCK_CNT(size, blk_desc) (PAD_COUNT(size, blk_desc->blksz))
107 #define PAD_TO_BLOCKSIZE(size, blk_desc) \
108 (PAD_SIZE(size, blk_desc->blksz))
110 #if CONFIG_IS_ENABLED(BLOCK_CACHE)
112 * blkcache_read() - attempt to read a set of blocks from cache
114 * @param iftype - uclass_id_x for type of device
115 * @param dev - device index of particular type
116 * @param start - starting block number
117 * @param blkcnt - number of blocks to read
118 * @param blksz - size in bytes of each block
119 * @param buffer - buffer to contain cached data
121 * Return: - 1 if block returned from cache, 0 otherwise.
123 int blkcache_read(int iftype, int dev,
124 lbaint_t start, lbaint_t blkcnt,
125 unsigned long blksz, void *buffer);
128 * blkcache_fill() - make data read from a block device available
131 * @param iftype - uclass_id_x for type of device
132 * @param dev - device index of particular type
133 * @param start - starting block number
134 * @param blkcnt - number of blocks available
135 * @param blksz - size in bytes of each block
136 * @param buffer - buffer containing data to cache
139 void blkcache_fill(int iftype, int dev,
140 lbaint_t start, lbaint_t blkcnt,
141 unsigned long blksz, void const *buffer);
144 * blkcache_invalidate() - discard the cache for a set of blocks
145 * because of a write or device (re)initialization.
147 * @iftype - UCLASS_ID_ for type of device, or -1 for any
148 * @dev - device index of particular type, if @iftype is not -1
150 void blkcache_invalidate(int iftype, int dev);
153 * blkcache_configure() - configure block cache
155 * @param blocks - maximum blocks per entry
156 * @param entries - maximum entries in cache
158 void blkcache_configure(unsigned blocks, unsigned entries);
161 * statistics of the block cache
163 struct block_cache_stats {
166 unsigned entries; /* current entry count */
167 unsigned max_blocks_per_entry;
168 unsigned max_entries;
172 * get_blkcache_stats() - return statistics and reset
174 * @param stats - statistics are copied here
176 void blkcache_stats(struct block_cache_stats *stats);
178 /** blkcache_free() - free all memory allocated to the block cache */
179 void blkcache_free(void);
183 static inline int blkcache_read(int iftype, int dev,
184 lbaint_t start, lbaint_t blkcnt,
185 unsigned long blksz, void *buffer)
190 static inline void blkcache_fill(int iftype, int dev,
191 lbaint_t start, lbaint_t blkcnt,
192 unsigned long blksz, void const *buffer) {}
194 static inline void blkcache_invalidate(int iftype, int dev) {}
196 static inline void blkcache_free(void) {}
200 #if CONFIG_IS_ENABLED(BLK)
203 /* Operations on block devices */
206 * read() - read from a block device
208 * @dev: Device to read from
209 * @start: Start block number to read (0=first)
210 * @blkcnt: Number of blocks to read
211 * @buffer: Destination buffer for data read
212 * @return number of blocks read, or -ve error number (see the
213 * IS_ERR_VALUE() macro
215 unsigned long (*read)(struct udevice *dev, lbaint_t start,
216 lbaint_t blkcnt, void *buffer);
219 * write() - write to a block device
221 * @dev: Device to write to
222 * @start: Start block number to write (0=first)
223 * @blkcnt: Number of blocks to write
224 * @buffer: Source buffer for data to write
225 * @return number of blocks written, or -ve error number (see the
226 * IS_ERR_VALUE() macro
228 unsigned long (*write)(struct udevice *dev, lbaint_t start,
229 lbaint_t blkcnt, const void *buffer);
232 * erase() - erase a section of a block device
234 * @dev: Device to (partially) erase
235 * @start: Start block number to erase (0=first)
236 * @blkcnt: Number of blocks to erase
237 * @return number of blocks erased, or -ve error number (see the
238 * IS_ERR_VALUE() macro
240 unsigned long (*erase)(struct udevice *dev, lbaint_t start,
244 * select_hwpart() - select a particular hardware partition
246 * Some devices (e.g. MMC) can support partitioning at the hardware
247 * level. This is quite separate from the normal idea of
248 * software-based partitions. MMC hardware partitions must be
249 * explicitly selected. Once selected only the region of the device
250 * covered by that partition is accessible.
252 * The MMC standard provides for two boot partitions (numbered 1 and 2),
253 * rpmb (3), and up to 4 addition general-purpose partitions (4-7).
255 * @dev: Block device to update
256 * @hwpart: Hardware partition number to select. 0 means the raw
257 * device, 1 is the first partition, 2 is the second, etc.
258 * @return 0 if OK, -ve on error
260 int (*select_hwpart)(struct udevice *dev, int hwpart);
262 #if IS_ENABLED(CONFIG_BOUNCE_BUFFER)
264 * buffer_aligned() - test memory alignment of block operation buffer
266 * Some devices have limited DMA capabilities and require that the
267 * buffers passed to them fit specific properties. This optional
268 * callback can be used to indicate whether a buffer alignment is
269 * suitable for the device DMA or not, and trigger use of generic
270 * bounce buffer implementation to help use of unsuitable buffers
271 * at the expense of performance degradation.
273 * @dev: Block device associated with the request
274 * @state: Bounce buffer state
275 * @return 1 if OK, 0 if unaligned
277 int (*buffer_aligned)(struct udevice *dev, struct bounce_buffer *state);
278 #endif /* CONFIG_BOUNCE_BUFFER */
282 * These functions should take struct udevice instead of struct blk_desc,
283 * but this is convenient for migration to driver model. Add a 'd' prefix
284 * to the function operations, so that blk_read(), etc. can be reserved for
285 * functions with the correct arguments.
287 unsigned long blk_dread(struct blk_desc *block_dev, lbaint_t start,
288 lbaint_t blkcnt, void *buffer);
289 unsigned long blk_dwrite(struct blk_desc *block_dev, lbaint_t start,
290 lbaint_t blkcnt, const void *buffer);
291 unsigned long blk_derase(struct blk_desc *block_dev, lbaint_t start,
295 * blk_read() - Read from a block device
297 * @dev: Device to read from
298 * @start: Start block for the read
299 * @blkcnt: Number of blocks to read
300 * @buf: Place to put the data
301 * @return number of blocks read (which may be less than @blkcnt),
302 * or -ve on error. This never returns 0 unless @blkcnt is 0
304 long blk_read(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
308 * blk_write() - Write to a block device
310 * @dev: Device to write to
311 * @start: Start block for the write
312 * @blkcnt: Number of blocks to write
313 * @buf: Data to write
314 * @return number of blocks written (which may be less than @blkcnt),
315 * or -ve on error. This never returns 0 unless @blkcnt is 0
317 long blk_write(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
321 * blk_erase() - Erase part of a block device
323 * @dev: Device to erase
324 * @start: Start block for the erase
325 * @blkcnt: Number of blocks to erase
326 * @return number of blocks erased (which may be less than @blkcnt),
327 * or -ve on error. This never returns 0 unless @blkcnt is 0
329 long blk_erase(struct udevice *dev, lbaint_t start, lbaint_t blkcnt);
332 * blk_find_device() - Find a block device
334 * This function does not activate the device. The device will be returned
335 * whether or not it is activated.
337 * @uclass_id: Interface type (enum uclass_id_t)
338 * @devnum: Device number (specific to each interface type)
339 * @devp: the device, if found
340 * Return: 0 if found, -ENODEV if no device found, or other -ve error value
342 int blk_find_device(int uclass_id, int devnum, struct udevice **devp);
345 * blk_get_device() - Find and probe a block device ready for use
347 * @uclass_id: Interface type (enum uclass_id_t)
348 * @devnum: Device number (specific to each interface type)
349 * @devp: the device, if found
350 * Return: 0 if found, -ENODEV if no device found, or other -ve error value
352 int blk_get_device(int uclass_id, int devnum, struct udevice **devp);
355 * blk_first_device() - Find the first device for a given interface
357 * The device is probed ready for use
359 * @devnum: Device number (specific to each interface type)
360 * @devp: the device, if found
361 * Return: 0 if found, -ENODEV if no device, or other -ve error value
363 int blk_first_device(int uclass_id, struct udevice **devp);
366 * blk_next_device() - Find the next device for a given interface
368 * This can be called repeatedly after blk_first_device() to iterate through
369 * all devices of the given interface type.
371 * The device is probed ready for use
373 * @devp: On entry, the previous device returned. On exit, the next
375 * Return: 0 if found, -ENODEV if no device, or other -ve error value
377 int blk_next_device(struct udevice **devp);
380 * blk_create_device() - Create a new block device
382 * @parent: Parent of the new device
383 * @drv_name: Driver name to use for the block device
384 * @name: Name for the device
385 * @uclass_id: Interface type (enum uclass_id_t)
386 * @devnum: Device number, specific to the interface type, or -1 to
387 * allocate the next available number
388 * @blksz: Block size of the device in bytes (typically 512)
389 * @lba: Total number of blocks of the device
390 * @devp: the new device (which has not been probed)
392 int blk_create_device(struct udevice *parent, const char *drv_name,
393 const char *name, int uclass_id, int devnum, int blksz,
394 lbaint_t lba, struct udevice **devp);
397 * blk_create_devicef() - Create a new named block device
399 * @parent: Parent of the new device
400 * @drv_name: Driver name to use for the block device
401 * @name: Name for the device (parent name is prepended)
402 * @uclass_id: Interface type (enum uclass_id_t)
403 * @devnum: Device number, specific to the interface type, or -1 to
404 * allocate the next available number
405 * @blksz: Block size of the device in bytes (typically 512)
406 * @lba: Total number of blocks of the device
407 * @devp: the new device (which has not been probed)
409 int blk_create_devicef(struct udevice *parent, const char *drv_name,
410 const char *name, int uclass_id, int devnum, int blksz,
411 lbaint_t lba, struct udevice **devp);
414 * blk_probe_or_unbind() - Try to probe
416 * Try to probe the device, primarily for enumerating partitions.
417 * If it fails, the device itself is unbound since it means that it won't
420 * @dev: The device to probe
421 * Return: 0 if OK, -ve on error
423 int blk_probe_or_unbind(struct udevice *dev);
426 * blk_unbind_all() - Unbind all device of the given interface type
428 * The devices are removed and then unbound.
430 * @uclass_id: Interface type to unbind
431 * Return: 0 if OK, -ve on error
433 int blk_unbind_all(int uclass_id);
436 * blk_find_max_devnum() - find the maximum device number for an interface type
438 * Finds the last allocated device number for an interface type @uclass_id. The
439 * next number is safe to use for a newly allocated device.
441 * @uclass_id: Interface type to scan
442 * Return: maximum device number found, or -ENODEV if none, or other -ve on
445 int blk_find_max_devnum(enum uclass_id uclass_id);
448 * blk_next_free_devnum() - get the next device number for an interface type
450 * Finds the next number that is safe to use for a newly allocated device for
451 * an interface type @uclass_id.
453 * @uclass_id: Interface type to scan
454 * Return: next device number safe to use, or -ve on error
456 int blk_next_free_devnum(enum uclass_id uclass_id);
459 * blk_select_hwpart() - select a hardware partition
461 * Select a hardware partition if the device supports it (typically MMC does)
463 * @dev: Device to update
464 * @hwpart: Partition number to select
465 * Return: 0 if OK, -ve on error
467 int blk_select_hwpart(struct udevice *dev, int hwpart);
470 * blk_find_from_parent() - find a block device by looking up its parent
472 * All block devices have a parent 'media' device which provides the block
473 * driver for the block device, ensuring that access to the underlying medium
476 * The block device is not activated by this function. See
477 * blk_get_from_parent() for that.
479 * @parent: Media device
480 * @devp: Returns the associated block device, if any
481 * Returns: 0 if OK, -ENODEV if @parent is not a media device and has no
484 int blk_find_from_parent(struct udevice *parent, struct udevice **devp);
487 * blk_get_from_parent() - obtain a block device by looking up its parent
489 * All block devices have a parent 'media' device which provides the block
490 * driver for the block device, ensuring that access to the underlying medium
493 * The block device is probed and ready for use.
495 * @parent: Media device
496 * @devp: Returns the associated block device, if any
497 * Returns: 0 if OK, -ENODEV if @parent is not a media device and has no
500 int blk_get_from_parent(struct udevice *parent, struct udevice **devp);
503 * blk_get_devtype() - Get the device type of a block device
505 * @dev: Block device to check
506 * Return: device tree, i.e. the uclass name of its parent, e.g. "mmc"
508 const char *blk_get_devtype(struct udevice *dev);
511 * blk_get_by_device() - Get the block device descriptor for the given device
512 * @dev: Instance of a storage device (the parent of the block device)
514 * Return: With block device descriptor on success , NULL if there is no such
517 struct blk_desc *blk_get_by_device(struct udevice *dev);
520 * blk_get_desc() - Get the block device descriptor for the given device number
522 * @uclass_id: Interface type
523 * @devnum: Device number (0 = first)
524 * @descp: Returns block device descriptor on success
525 * Return: 0 on success, -ENODEV if there is no such device and no device
526 * with a higher device number, -ENOENT if there is no such device but there
527 * is one with a higher number, or other -ve on other error.
529 int blk_get_desc(enum uclass_id uclass_id, int devnum, struct blk_desc **descp);
534 * These functions should take struct udevice instead of struct blk_desc,
535 * but this is convenient for migration to driver model. Add a 'd' prefix
536 * to the function operations, so that blk_read(), etc. can be reserved for
537 * functions with the correct arguments.
539 static inline ulong blk_dread(struct blk_desc *block_dev, lbaint_t start,
540 lbaint_t blkcnt, void *buffer)
543 if (blkcache_read(block_dev->uclass_id, block_dev->devnum,
544 start, blkcnt, block_dev->blksz, buffer))
548 * We could check if block_read is NULL and return -ENOSYS. But this
549 * bloats the code slightly (cause some board to fail to build), and
550 * it would be an error to try an operation that does not exist.
552 blks_read = block_dev->block_read(block_dev, start, blkcnt, buffer);
553 if (blks_read == blkcnt)
554 blkcache_fill(block_dev->uclass_id, block_dev->devnum,
555 start, blkcnt, block_dev->blksz, buffer);
560 static inline ulong blk_dwrite(struct blk_desc *block_dev, lbaint_t start,
561 lbaint_t blkcnt, const void *buffer)
563 blkcache_invalidate(block_dev->uclass_id, block_dev->devnum);
564 return block_dev->block_write(block_dev, start, blkcnt, buffer);
567 static inline ulong blk_derase(struct blk_desc *block_dev, lbaint_t start,
570 blkcache_invalidate(block_dev->uclass_id, block_dev->devnum);
571 return block_dev->block_erase(block_dev, start, blkcnt);
575 * struct blk_driver - Driver for block interface types
577 * This provides access to the block devices for each interface type. One
578 * driver should be provided using U_BOOT_LEGACY_BLK() for each interface
579 * type that is to be supported.
581 * @uclass_idname: Interface type name
582 * @uclass_id: Interface type
583 * @max_devs: Maximum number of devices supported
584 * @desc: Pointer to list of devices for this interface type,
585 * or NULL to use @get_dev() instead
588 const char *uclass_idname;
589 enum uclass_id uclass_id;
591 struct blk_desc *desc;
593 * get_dev() - get a pointer to a block device given its number
595 * Each interface allocates its own devices and typically
596 * struct blk_desc is contained with the interface's data structure.
597 * There is no global numbering for block devices. This method allows
598 * the device for an interface type to be obtained when @desc is NULL.
600 * @devnum: Device number (0 for first device on that interface,
602 * @descp: Returns pointer to the block device on success
603 * @return 0 if OK, -ve on error
605 int (*get_dev)(int devnum, struct blk_desc **descp);
608 * select_hwpart() - Select a hardware partition
610 * Some devices (e.g. MMC) can support partitioning at the hardware
611 * level. This is quite separate from the normal idea of
612 * software-based partitions. MMC hardware partitions must be
613 * explicitly selected. Once selected only the region of the device
614 * covered by that partition is accessible.
616 * The MMC standard provides for two boot partitions (numbered 1 and 2),
617 * rpmb (3), and up to 4 addition general-purpose partitions (4-7).
618 * Partition 0 is the main user-data partition.
620 * @desc: Block device descriptor
621 * @hwpart: Hardware partition number to select. 0 means the main
622 * user-data partition, 1 is the first partition, 2 is
624 * @return 0 if OK, other value for an error
626 int (*select_hwpart)(struct blk_desc *desc, int hwpart);
630 * Declare a new U-Boot legacy block driver. New drivers should use driver
631 * model (UCLASS_BLK).
633 #define U_BOOT_LEGACY_BLK(__name) \
634 ll_entry_declare(struct blk_driver, __name, blk_driver)
636 struct blk_driver *blk_driver_lookup_type(int uclass_id);
638 #endif /* !CONFIG_BLK */
641 * blk_get_devnum_by_uclass_idname() - Get a block device by type and number
643 * This looks through the available block devices of the given type, returning
644 * the one with the given @devnum.
646 * @uclass_id: Block device type
647 * @devnum: Device number
648 * Return: point to block device descriptor, or NULL if not found
650 struct blk_desc *blk_get_devnum_by_uclass_id(enum uclass_id uclass_id, int devnum);
653 * blk_get_devnum_by_uclass_idname() - Get block device by type name and number
655 * This looks up the block device type based on @uclass_idname, then calls
656 * blk_get_devnum_by_uclass_id().
658 * @uclass_idname: Block device type name
659 * @devnum: Device number
660 * Return: point to block device descriptor, or NULL if not found
662 struct blk_desc *blk_get_devnum_by_uclass_idname(const char *uclass_idname,
666 * blk_dselect_hwpart() - select a hardware partition
668 * This selects a hardware partition (such as is supported by MMC). The block
669 * device size may change as this effectively points the block device to a
670 * partition at the hardware level. See the select_hwpart() method above.
672 * @desc: Block device descriptor for the device to select
673 * @hwpart: Partition number to select
674 * Return: 0 if OK, -ve on error
676 int blk_dselect_hwpart(struct blk_desc *desc, int hwpart);
679 * blk_list_part() - list the partitions for block devices of a given type
681 * This looks up the partition type for each block device of type @uclass_id,
682 * then displays a list of partitions.
684 * @uclass_id: Block device type
685 * Return: 0 if OK, -ENODEV if there is none of that type
687 int blk_list_part(enum uclass_id uclass_id);
690 * blk_list_devices() - list the block devices of a given type
692 * This lists each block device of the type @uclass_id, showing the capacity
693 * as well as type-specific information.
695 * @uclass_id: Block device type
697 void blk_list_devices(enum uclass_id uclass_id);
700 * blk_show_device() - show information about a given block device
702 * This shows the block device capacity as well as type-specific information.
704 * @uclass_id: Block device type
705 * @devnum: Device number
706 * Return: 0 if OK, -ENODEV for invalid device number
708 int blk_show_device(enum uclass_id uclass_id, int devnum);
711 * blk_print_device_num() - show information about a given block device
713 * This is similar to blk_show_device() but returns an error if the block
714 * device type is unknown.
716 * @uclass_id: Block device type
717 * @devnum: Device number
718 * Return: 0 if OK, -ENODEV for invalid device number, -ENOENT if the block
719 * device is not connected
721 int blk_print_device_num(enum uclass_id uclass_id, int devnum);
724 * blk_print_part_devnum() - print the partition information for a device
726 * @uclass_id: Block device type
727 * @devnum: Device number
728 * Return: 0 if OK, -ENOENT if the block device is not connected, -ENOSYS if
729 * the interface type is not supported, other -ve on other error
731 int blk_print_part_devnum(enum uclass_id uclass_id, int devnum);
734 * blk_select_hwpart_devnum() - select a hardware partition
736 * This is similar to blk_dselect_hwpart() but it looks up the interface and
739 * @uclass_id: Block device type
740 * @devnum: Device number
741 * @hwpart: Partition number to select
742 * Return: 0 if OK, -ve on error
744 int blk_select_hwpart_devnum(enum uclass_id uclass_id, int devnum, int hwpart);
747 * blk_get_uclass_name() - Get the name of an interface type
749 * @uclass_id: Interface type to check
750 * Return: name of interface, or NULL if none
752 const char *blk_get_uclass_name(enum uclass_id uclass_id);
755 * blk_common_cmd() - handle common commands with block devices
757 * @args: Number of arguments to the command (argv[0] is the command itself)
758 * @argv: Command arguments
759 * @uclass_id: Interface type
760 * @cur_devnump: Current device number for this interface type
761 * Return: 0 if OK, CMD_RET_ERROR on error
763 int blk_common_cmd(int argc, char *const argv[], enum uclass_id uclass_id,
768 BLKF_REMOVABLE = 1 << 1,
769 BLKF_BOTH = BLKF_FIXED | BLKF_REMOVABLE,
773 * blk_first_device_err() - Get the first block device
775 * The device returned is probed if necessary, and ready for use
777 * @flags: Indicates type of device to return
778 * @devp: Returns pointer to the first device in that uclass, or NULL if none
779 * Return: 0 if found, -ENODEV if not found, other -ve on error
781 int blk_first_device_err(enum blk_flag_t flags, struct udevice **devp);
784 * blk_next_device_err() - Get the next block device
786 * The device returned is probed if necessary, and ready for use
788 * @flags: Indicates type of device to return
789 * @devp: On entry, pointer to device to lookup. On exit, returns pointer
790 * to the next device in the uclass if no error occurred, or -ENODEV if
791 * there is no next device.
792 * Return: 0 if found, -ENODEV if not found, other -ve on error
794 int blk_next_device_err(enum blk_flag_t flags, struct udevice **devp);
797 * blk_find_first() - Return the first matching block device
798 * @flags: Indicates type of device to return
799 * @devp: Returns pointer to device, or NULL on error
801 * The device is not prepared for use - this is an internal function.
802 * The function uclass_get_device_tail() can be used to probe the device.
804 * Note that some devices are considered removable until they have been probed
806 * @return 0 if found, -ENODEV if not found
808 int blk_find_first(enum blk_flag_t flags, struct udevice **devp);
811 * blk_find_next() - Return the next matching block device
812 * @flags: Indicates type of device to return
813 * @devp: On entry, pointer to device to lookup. On exit, returns pointer
814 * to the next device in the same uclass, or NULL if none
816 * The device is not prepared for use - this is an internal function.
817 * The function uclass_get_device_tail() can be used to probe the device.
819 * Note that some devices are considered removable until they have been probed
821 * @return 0 if found, -ENODEV if not found
823 int blk_find_next(enum blk_flag_t flags, struct udevice **devp);
826 * blk_foreach() - iterate through block devices
828 * This creates a for() loop which works through the available block devices in
829 * order from start to end.
831 * If for some reason the uclass cannot be found, this does nothing.
833 * @_flags: Indicates type of device to return
834 * @_pos: struct udevice * to hold the current device. Set to NULL when there
835 * are no more devices.
837 #define blk_foreach(_flags, _pos) \
838 for (int _ret = blk_find_first(_flags, &_pos); !_ret && _pos; \
839 _ret = blk_find_next(_flags, &_pos))
842 * blk_foreach_probe() - Helper function to iteration through block devices
844 * This creates a for() loop which works through the available devices in
845 * a uclass in order from start to end. Devices are probed if necessary,
848 * @flags: Indicates type of device to return
849 * @dev: struct udevice * to hold the current device. Set to NULL when there
850 * are no more devices.
852 #define blk_foreach_probe(flags, pos) \
853 for (int _ret = blk_first_device_err(flags, &(pos)); \
855 _ret = blk_next_device_err(flags, &(pos)))
858 * blk_count_devices() - count the number of devices of a particular type
860 * @flags: Indicates type of device to find
861 * Return: number of devices matching those flags
863 int blk_count_devices(enum blk_flag_t flag);