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dm: blk: Add a way to obtain a block device from its parent

Many devices support a child block device (e.g. MMC, USB). Add a
convenient way to get this device given the parent device.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
tags/2020-06-01
Simon Glass 4 years ago
committed by Jaehoon Chung
parent
commit
9f103b9cb5
3 changed files with 51 additions and 0 deletions
  1. +26
    -0
      drivers/block/blk-uclass.c
  2. +7
    -0
      include/blk.h
  3. +18
    -0
      test/dm/blk.c

+ 26
- 0
drivers/block/blk-uclass.c View File

@@ -453,6 +453,32 @@ int blk_prepare_device(struct udevice *dev)
return 0;
}

int blk_get_from_parent(struct udevice *parent, struct udevice **devp)
{
struct udevice *dev;
enum uclass_id id;
int ret;

device_find_first_child(parent, &dev);
if (!dev) {
debug("%s: No block device found for parent '%s'\n", __func__,
parent->name);
return -ENODEV;
}
id = device_get_uclass_id(dev);
if (id != UCLASS_BLK) {
debug("%s: Incorrect uclass %s for block device '%s'\n",
__func__, uclass_get_name(id), dev->name);
return -ENOTBLK;
}
ret = device_probe(dev);
if (ret)
return ret;
*devp = dev;

return 0;
}

int blk_find_max_devnum(enum if_type if_type)
{
struct udevice *dev;


+ 7
- 0
include/blk.h View File

@@ -616,4 +616,11 @@ ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
*/
int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart);

/**
* blk_get_from_parent() - obtain a block device by looking up its parent
*
* All devices with
*/
int blk_get_from_parent(struct udevice *parent, struct udevice **devp);

#endif

+ 18
- 0
test/dm/blk.c View File

@@ -150,3 +150,21 @@ static int dm_test_blk_devnum(struct unit_test_state *uts)
return 0;
}
DM_TEST(dm_test_blk_devnum, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);

/* Test that we can get a block from its parent */
static int dm_test_blk_get_from_parent(struct unit_test_state *uts)
{
struct udevice *dev, *blk;

ut_assertok(uclass_get_device(UCLASS_MMC, 0, &dev));
ut_assertok(blk_get_from_parent(dev, &blk));

ut_assertok(uclass_get_device(UCLASS_I2C, 0, &dev));
ut_asserteq(-ENOTBLK, blk_get_from_parent(dev, &blk));

ut_assertok(uclass_get_device(UCLASS_GPIO, 0, &dev));
ut_asserteq(-ENODEV, blk_get_from_parent(dev, &blk));

return 0;
}
DM_TEST(dm_test_blk_get_from_parent, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);