Re: [U-Boot] [PATCH 1/3] dm: blk: Add a way to obtain a block device from its parent

Hi Simon,

On 05/28/2017 02:37 AM, Simon Glass wrote:

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

drivers/block/blk-uclass.c | 26 ++++++++++++++++++++++++++ include/blk.h | 7 +++++++ test/dm/blk.c | 18 ++++++++++++++++++ 3 files changed, 51 insertions(+)

diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c index 6145675271..23f131b7ad 100644 --- a/drivers/block/blk-uclass.c +++ b/drivers/block/blk-uclass.c @@ -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; diff --git a/include/blk.h b/include/blk.h index a128ee4841..4d60987f61 100644 --- a/include/blk.h +++ b/include/blk.h @@ -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);

Don't need to consider whether CONFIG_BLK is defined or not? blk_get_from_parent() is declared in blk-uclass.c

Best Regards, Jaehoon Chung

#endif diff --git a/test/dm/blk.c b/test/dm/blk.c index 5c5eb829a0..923e8d95f0 100644 --- a/test/dm/blk.c +++ b/test/dm/blk.c @@ -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);