dm: blk: Add udevice functions

At present we have functions called blk_dread(), etc., which take a
struct blk_desc * to refer to the block device. Add some functions which
use udevice instead, since this is more in keeping with how driver model
is supposed to work.

Update one of the tests to use this.

Note that it would be nice to update the functions in disk-uclass.c to use
these new functions. However they are not quite the same. For example,
disk_blk_read() adds the partition offset to 'start' when calling the
cache read/fill functions, but does not with part_blk_read(), which does
the addition itself. So as designed the code is duplicated.

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

drivers/block/blk-uclass.c

@@ -444,53 +444,70 @@ int blk_get_device(int uclass_id, int devnum, struct udevice **devp)
 	return device_probe(*devp);
 }
 
-unsigned long blk_dread(struct blk_desc *block_dev, lbaint_t start,
-			lbaint_t blkcnt, void *buffer)
+long blk_read(struct udevice *dev, lbaint_t start, lbaint_t blkcnt, void *buf)
 {
-	struct udevice *dev = block_dev->bdev;
+	struct blk_desc *desc = dev_get_uclass_plat(dev);
 	const struct blk_ops *ops = blk_get_ops(dev);
 	ulong blks_read;
 
 	if (!ops->read)
 		return -ENOSYS;
 
-	if (blkcache_read(block_dev->uclass_id, block_dev->devnum,
-			  start, blkcnt, block_dev->blksz, buffer))
+	if (blkcache_read(desc->uclass_id, desc->devnum,
+			  start, blkcnt, desc->blksz, buf))
 		return blkcnt;
-	blks_read = ops->read(dev, start, blkcnt, buffer);
+	blks_read = ops->read(dev, start, blkcnt, buf);
 	if (blks_read == blkcnt)
-		blkcache_fill(block_dev->uclass_id, block_dev->devnum,
-			      start, blkcnt, block_dev->blksz, buffer);
+		blkcache_fill(desc->uclass_id, desc->devnum, start, blkcnt,
+			      desc->blksz, buf);
 
 	return blks_read;
 }
 
-unsigned long blk_dwrite(struct blk_desc *block_dev, lbaint_t start,
-			 lbaint_t blkcnt, const void *buffer)
+long blk_write(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+	       const void *buf)
 {
-	struct udevice *dev = block_dev->bdev;
+	struct blk_desc *desc = dev_get_uclass_plat(dev);
 	const struct blk_ops *ops = blk_get_ops(dev);
 
 	if (!ops->write)
 		return -ENOSYS;
 
-	blkcache_invalidate(block_dev->uclass_id, block_dev->devnum);
-	return ops->write(dev, start, blkcnt, buffer);
+	blkcache_invalidate(desc->uclass_id, desc->devnum);
+
+	return ops->write(dev, start, blkcnt, buf);
 }
 
-unsigned long blk_derase(struct blk_desc *block_dev, lbaint_t start,
-			 lbaint_t blkcnt)
+long blk_erase(struct udevice *dev, lbaint_t start, lbaint_t blkcnt)
 {
-	struct udevice *dev = block_dev->bdev;
+	struct blk_desc *desc = dev_get_uclass_plat(dev);
 	const struct blk_ops *ops = blk_get_ops(dev);
 
 	if (!ops->erase)
 		return -ENOSYS;
 
-	blkcache_invalidate(block_dev->uclass_id, block_dev->devnum);
+	blkcache_invalidate(desc->uclass_id, desc->devnum);
+
 	return ops->erase(dev, start, blkcnt);
 }
 
+ulong blk_dread(struct blk_desc *desc, lbaint_t start, lbaint_t blkcnt,
+		void *buffer)
+{
+	return blk_read(desc->bdev, start, blkcnt, buffer);
+}
+
+ulong blk_dwrite(struct blk_desc *desc, lbaint_t start, lbaint_t blkcnt,
+		 const void *buffer)
+{
+	return blk_write(desc->bdev, start, blkcnt, buffer);
+}
+
+ulong blk_derase(struct blk_desc *desc, lbaint_t start, lbaint_t blkcnt)
+{
+	return blk_erase(desc->bdev, start, blkcnt);
+}
+
 int blk_get_from_parent(struct udevice *parent, struct udevice **devp)
 {
 	struct udevice *dev;

include/blk.h

@@ -273,6 +273,43 @@ unsigned long blk_dwrite(struct blk_desc *block_dev, lbaint_t start,
 unsigned long blk_derase(struct blk_desc *block_dev, lbaint_t start,
 			 lbaint_t blkcnt);
 
+/**
+ * blk_read() - Read from a block device
+ *
+ * @dev: Device to read from
+ * @start: Start block for the read
+ * @blkcnt: Number of blocks to read
+ * @buf: Place to put the data
+ * @return number of blocks read (which may be less than @blkcnt),
+ * or -ve on error. This never returns 0 unless @blkcnt is 0
+ */
+long blk_read(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+	      void *buffer);
+
+/**
+ * blk_write() - Write to a block device
+ *
+ * @dev: Device to write to
+ * @start: Start block for the write
+ * @blkcnt: Number of blocks to write
+ * @buf: Data to write
+ * @return number of blocks written (which may be less than @blkcnt),
+ * or -ve on error. This never returns 0 unless @blkcnt is 0
+ */
+long blk_write(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+	       const void *buffer);
+
+/**
+ * blk_erase() - Erase part of a block device
+ *
+ * @dev: Device to erase
+ * @start: Start block for the erase
+ * @blkcnt: Number of blocks to erase
+ * @return number of blocks erased (which may be less than @blkcnt),
+ * or -ve on error. This never returns 0 unless @blkcnt is 0
+ */
+long blk_erase(struct udevice *dev, lbaint_t start, lbaint_t blkcnt);
+
 /**
  * blk_find_device() - Find a block device
  *
@@ -428,7 +465,7 @@ const char *blk_get_devtype(struct udevice *dev);
 
 /**
  * blk_get_by_device() - Get the block device descriptor for the given device
- * @dev:	Instance of a storage device
+ * @dev:	Instance of a storage device (the parent of the block device)
  *
  * Return: With block device descriptor on success , NULL if there is no such
  *	   block device.

test/dm/usb.c

@@ -43,19 +43,24 @@ DM_TEST(dm_test_usb_base, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
  */
 static int dm_test_usb_flash(struct unit_test_state *uts)
 {
-	struct udevice *dev;
-	struct blk_desc *dev_desc;
+	struct blk_desc *dev_desc, *chk;
+	struct udevice *dev, *blk;
 	char cmp[1024];
 
 	state_set_skip_delays(true);
 	ut_assertok(usb_init());
 	ut_assertok(uclass_get_device(UCLASS_MASS_STORAGE, 0, &dev));
 	ut_assertok(blk_get_device_by_str("usb", "0", &dev_desc));
+	chk = blk_get_by_device(dev);
+	ut_asserteq_ptr(chk, dev_desc);
+
+	ut_assertok(device_find_first_child_by_uclass(dev, UCLASS_BLK, &blk));
+	ut_asserteq_ptr(chk, blk_get_by_device(dev));
 
 	/* Read a few blocks and look for the string we expect */
 	ut_asserteq(512, dev_desc->blksz);
 	memset(cmp, '\0', sizeof(cmp));
-	ut_asserteq(2, blk_dread(dev_desc, 0, 2, cmp));
+	ut_asserteq(2, blk_read(blk, 0, 2, cmp));
 	ut_assertok(strcmp(cmp, "this is a test"));
 	ut_assertok(usb_stop());