[PATCH 3/3] mmc: use SD/MMC host ID for block device name ID

Douglas Anderson
2016-04-28T23:06:45Z

From: Stefan Agner <stefan@agner.ch>

By using the SD/MMC host device ID as a starting point for block
device numbering, one can reliably predict the first block device
name (at least for the first controller). This is especially useful
for SoCs with multiple SD/MMC host controller, where the controller
with index 0 is connected to a eMMC device.

Usually the first controller gets the first block device name ID,
however this is not guaranteed. Also if the first controller is
aliased as second controller and visa-versa (using device tree
aliases), the block device name ID assignation is not ordered by
the SD/MMC host device ID (since mmc_rescan is called in order of
the memory mapped pheripherial addresses).

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
drivers/mmc/card/block.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 9fef7f04c4e6..bcf4fdbb5221 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2215,7 +2215,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
* index anymore so we keep track of a name index.
*/
if (!subname) {
- md->name_idx = find_first_zero_bit(name_use, max_devices);
+ md->name_idx = find_next_zero_bit(name_use, max_devices,
+ card->host->index);
__set_bit(md->name_idx, name_use);
} else
md->name_idx = ((struct mmc_blk_data *)
--
2.8.0.rc3.226.g39d4020