dm: blk: Add a legacy block interface

There is quite a bit of duplicated common code related to block devices
in the IDE and SCSI implementations.

Create some helper functions that can be used to reduce the duplication.
These rely on a linker list of interface-type drivers

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/block/Makefile

@@ -7,6 +7,10 @@
 
 obj-$(CONFIG_BLK) += blk-uclass.o
 
+ifndef CONFIG_BLK
+obj-y += blk_legacy.o
+endif
+
 obj-$(CONFIG_AHCI) += ahci-uclass.o
 obj-$(CONFIG_SCSI_AHCI) += ahci.o
 obj-$(CONFIG_DWC_AHSATA) += dwc_ahsata.o

drivers/block/blk_legacy.c

+/*
+ * Copyright (C) 2016 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <linux/err.h>
+
+struct blk_driver *blk_driver_lookup_type(int if_type)
+{
+	struct blk_driver *drv = ll_entry_start(struct blk_driver, blk_driver);
+	const int n_ents = ll_entry_count(struct blk_driver, blk_driver);
+	struct blk_driver *entry;
+
+	for (entry = drv; entry != drv + n_ents; entry++) {
+		if (if_type == entry->if_type)
+			return entry;
+	}
+
+	/* Not found */
+	return NULL;
+}
+
+static struct blk_driver *blk_driver_lookup_typename(const char *if_typename)
+{
+	struct blk_driver *drv = ll_entry_start(struct blk_driver, blk_driver);
+	const int n_ents = ll_entry_count(struct blk_driver, blk_driver);
+	struct blk_driver *entry;
+
+	for (entry = drv; entry != drv + n_ents; entry++) {
+		if (!strcmp(if_typename, entry->if_typename))
+			return entry;
+	}
+
+	/* Not found */
+	return NULL;
+}
+
+/**
+ * get_desc() - Get the block device descriptor for the given device number
+ *
+ * @drv:	Legacy block driver
+ * @devnum:	Device number (0 = first)
+ * @descp:	Returns block device descriptor on success
+ * @return 0 on success, -ENODEV if there is no such device, -ENOSYS if the
+ * driver does not provide a way to find a device, or other -ve on other
+ * error.
+ */
+static int get_desc(struct blk_driver *drv, int devnum, struct blk_desc **descp)
+{
+	if (drv->desc) {
+		if (devnum < 0 || devnum >= drv->max_devs)
+			return -ENODEV;
+		*descp = &drv->desc[devnum];
+		return 0;
+	}
+	if (!drv->get_dev)
+		return -ENOSYS;
+
+	return drv->get_dev(devnum, descp);
+}
+
+#ifdef HAVE_BLOCK_DEVICE
+int blk_list_part(enum if_type if_type)
+{
+	struct blk_driver *drv;
+	struct blk_desc *desc;
+	int devnum, ok;
+	bool first = true;
+
+	drv = blk_driver_lookup_type(if_type);
+	if (!drv)
+		return -ENOSYS;
+	for (ok = 0, devnum = 0; devnum < drv->max_devs; ++devnum) {
+		if (get_desc(drv, devnum, &desc))
+			continue;
+		if (desc->part_type != PART_TYPE_UNKNOWN) {
+			++ok;
+			if (!first)
+				putc('\n');
+			part_print(desc);
+			first = false;
+		}
+	}
+	if (!ok)
+		return -ENODEV;
+
+	return 0;
+}
+
+int blk_print_part_devnum(enum if_type if_type, int devnum)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	int ret;
+
+	if (!drv)
+		return -ENOSYS;
+	ret = get_desc(drv, 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_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	int i;
+
+	if (!drv)
+		return;
+	for (i = 0; i < drv->max_devs; ++i) {
+		if (get_desc(drv, i, &desc))
+			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_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	int ret;
+
+	if (!drv)
+		return -ENOSYS;
+	ret = get_desc(drv, devnum, &desc);
+	if (ret)
+		return ret;
+	printf("\n%s device %d: ", drv->if_typename, devnum);
+	dev_print(desc);
+
+	return 0;
+}
+
+int blk_show_device(enum if_type if_type, int devnum)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	int ret;
+
+	if (!drv)
+		return -ENOSYS;
+	printf("\nDevice %d: ", devnum);
+	if (devnum >= drv->max_devs) {
+		puts("unknown device\n");
+		return -ENODEV;
+	}
+	ret = get_desc(drv, devnum, &desc);
+	if (ret)
+		return ret;
+	dev_print(desc);
+
+	if (desc->type == DEV_TYPE_UNKNOWN)
+		return -ENOENT;
+
+	return 0;
+}
+#endif /* HAVE_BLOCK_DEVICE */
+
+struct blk_desc *blk_get_devnum_by_type(enum if_type if_type, int devnum)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+
+	if (!drv)
+		return NULL;
+
+	if (get_desc(drv, devnum, &desc))
+		return NULL;
+
+	return desc;
+}
+
+int blk_dselect_hwpart(struct blk_desc *desc, int hwpart)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(desc->if_type);
+
+	if (!drv)
+		return -ENOSYS;
+	if (drv->select_hwpart)
+		return drv->select_hwpart(desc, hwpart);
+
+	return 0;
+}
+
+struct blk_desc *blk_get_devnum_by_typename(const char *if_typename, int devnum)
+{
+	struct blk_driver *drv = blk_driver_lookup_typename(if_typename);
+	struct blk_desc *desc;
+
+	if (!drv)
+		return NULL;
+
+	if (get_desc(drv, devnum, &desc))
+		return NULL;
+
+	return desc;
+}
+
+ulong blk_read_devnum(enum if_type if_type, int devnum, lbaint_t start,
+		      lbaint_t blkcnt, void *buffer)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	ulong n;
+	int ret;
+
+	if (!drv)
+		return -ENOSYS;
+	ret = get_desc(drv, devnum, &desc);
+	if (ret)
+		return ret;
+	n = desc->block_read(desc, start, blkcnt, buffer);
+	if (IS_ERR_VALUE(n))
+		return n;
+
+	/* flush cache after read */
+	flush_cache((ulong)buffer, blkcnt * desc->blksz);
+
+	return n;
+}
+
+ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
+		       lbaint_t blkcnt, const void *buffer)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	int ret;
+
+	if (!drv)
+		return -ENOSYS;
+	ret = get_desc(drv, devnum, &desc);
+	if (ret)
+		return ret;
+	return desc->block_write(desc, start, blkcnt, buffer);
+}
+
+int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart)
+{
+	struct blk_driver *drv = blk_driver_lookup_type(if_type);
+	struct blk_desc *desc;
+	int ret;
+
+	if (!drv)
+		return -ENOSYS;
+	ret = get_desc(drv, devnum, &desc);
+	if (ret)
+		return ret;
+	return drv->select_hwpart(desc, hwpart);
+}

include/blk.h

@@ -340,6 +340,201 @@ static inline ulong blk_derase(struct blk_desc *block_dev, lbaint_t start,
 	blkcache_invalidate(block_dev->if_type, block_dev->devnum);
 	return block_dev->block_erase(block_dev, start, blkcnt);
 }
+
+/**
+ * struct blk_driver - Driver for block interface types
+ *
+ * This provides access to the block devices for each interface type. One
+ * driver should be provided using U_BOOT_LEGACY_BLK() for each interface
+ * type that is to be supported.
+ *
+ * @if_typename:	Interface type name
+ * @if_type:		Interface type
+ * @max_devs:		Maximum number of devices supported
+ * @desc:		Pointer to list of devices for this interface type,
+ *			or NULL to use @get_dev() instead
+ */
+struct blk_driver {
+	const char *if_typename;
+	enum if_type if_type;
+	int max_devs;
+	struct blk_desc *desc;
+	/**
+	 * get_dev() - get a pointer to a block device given its number
+	 *
+	 * Each interface allocates its own devices and typically
+	 * struct blk_desc is contained with the interface's data structure.
+	 * There is no global numbering for block devices. This method allows
+	 * the device for an interface type to be obtained when @desc is NULL.
+	 *
+	 * @devnum:	Device number (0 for first device on that interface,
+	 *		1 for second, etc.
+	 * @descp:	Returns pointer to the block device on success
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_dev)(int devnum, struct blk_desc **descp);
+
+	/**
+	 * select_hwpart() - Select a hardware partition
+	 *
+	 * Some devices (e.g. MMC) can support partitioning at the hardware
+	 * level. This is quite separate from the normal idea of
+	 * software-based partitions. MMC hardware partitions must be
+	 * explicitly selected. Once selected only the region of the device
+	 * covered by that partition is accessible.
+	 *
+	 * The MMC standard provides for two boot partitions (numbered 1 and 2),
+	 * rpmb (3), and up to 4 addition general-purpose partitions (4-7).
+	 * Partition 0 is the main user-data partition.
+	 *
+	 * @desc:	Block device descriptor
+	 * @hwpart:	Hardware partition number to select. 0 means the main
+	 *		user-data partition, 1 is the first partition, 2 is
+	 *		the second, etc.
+	 * @return 0 if OK, other value for an error
+	 */
+	int (*select_hwpart)(struct blk_desc *desc, int hwpart);
+};
+
+/*
+ * Declare a new U-Boot legacy block driver. New drivers should use driver
+ * model (UCLASS_BLK).
+ */
+#define U_BOOT_LEGACY_BLK(__name)					\
+	ll_entry_declare(struct blk_driver, __name, blk_driver)
+
+struct blk_driver *blk_driver_lookup_type(int if_type);
+
 #endif /* !CONFIG_BLK */
 
+/**
+ * blk_get_devnum_by_typename() - Get a block device by type and number
+ *
+ * This looks through the available block devices of the given type, returning
+ * the one with the given @devnum.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return point to block device descriptor, or NULL if not found
+ */
+struct blk_desc *blk_get_devnum_by_type(enum if_type if_type, int devnum);
+
+/**
+ * blk_get_devnum_by_type() - Get a block device by type name, and number
+ *
+ * This looks up the block device type based on @if_typename, then calls
+ * blk_get_devnum_by_type().
+ *
+ * @if_typename:	Block device type name
+ * @devnum:		Device number
+ * @return point to block device descriptor, or NULL if not found
+ */
+struct blk_desc *blk_get_devnum_by_typename(const char *if_typename,
+					    int devnum);
+
+/**
+ * blk_dselect_hwpart() - select a hardware partition
+ *
+ * This selects a hardware partition (such as is supported by MMC). The block
+ * device size may change as this effectively points the block device to a
+ * partition at the hardware level. See the select_hwpart() method above.
+ *
+ * @desc:	Block device descriptor for the device to select
+ * @hwpart:	Partition number to select
+ * @return 0 if OK, -ve on error
+ */
+int blk_dselect_hwpart(struct blk_desc *desc, int hwpart);
+
+/**
+ * blk_list_part() - list the partitions for block devices of a given type
+ *
+ * This looks up the partition type for each block device of type @if_type,
+ * then displays a list of partitions.
+ *
+ * @if_type:	Block device type
+ * @return 0 if OK, -ENODEV if there is none of that type
+ */
+int blk_list_part(enum if_type if_type);
+
+/**
+ * blk_list_devices() - list the block devices of a given type
+ *
+ * This lists each block device of the type @if_type, showing the capacity
+ * as well as type-specific information.
+ *
+ * @if_type:	Block device type
+ */
+void blk_list_devices(enum if_type if_type);
+
+/**
+ * blk_show_device() - show information about a given block device
+ *
+ * This shows the block device capacity as well as type-specific information.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return 0 if OK, -ENODEV for invalid device number
+ */
+int blk_show_device(enum if_type if_type, int devnum);
+
+/**
+ * blk_print_device_num() - show information about a given block device
+ *
+ * This is similar to blk_show_device() but returns an error if the block
+ * device type is unknown.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return 0 if OK, -ENODEV for invalid device number, -ENOENT if the block
+ * device is not connected
+ */
+int blk_print_device_num(enum if_type if_type, int devnum);
+
+/**
+ * blk_print_part_devnum() - print the partition information for a device
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return 0 if OK, -ENOENT if the block device is not connected, -ENOSYS if
+ * the interface type is not supported, other -ve on other error
+ */
+int blk_print_part_devnum(enum if_type if_type, int devnum);
+
+/**
+ * blk_read_devnum() - read blocks from a device
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @blkcnt:	Number of blocks to read
+ * @buffer:	Address to write data to
+ * @return number of blocks read, or -ve error number on error
+ */
+ulong blk_read_devnum(enum if_type if_type, int devnum, lbaint_t start,
+		      lbaint_t blkcnt, void *buffer);
+
+/**
+ * blk_write_devnum() - write blocks to a device
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @blkcnt:	Number of blocks to write
+ * @buffer:	Address to read data from
+ * @return number of blocks written, or -ve error number on error
+ */
+ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
+		       lbaint_t blkcnt, const void *buffer);
+
+/**
+ * blk_select_hwpart_devnum() - select a hardware partition
+ *
+ * This is similar to blk_dselect_hwpart() but it looks up the interface and
+ * device number.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @hwpart:	Partition number to select
+ * @return 0 if OK, -ve on error
+ */
+int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart);
+
 #endif