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

@@ -0,0 +1,261 @@
+/*
+ * 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);
+}