[PATCH 1/1] mmc: Fix mmc_switch excessive timeout

[PATCH 1/1] mmc: Fix mmc_switch excessive timeout

[Kirill Kapranov]

Fix branching to avoid premature falling back on a long timeout instead
of continuation of the initialization attempt.

Clear of the comment to avoid the ambiguity.

Signed-off-by: Kirill Kapranov <kirill.kapranov@compulab.co.il>
Cc: Pantelis Antoniou <panto@antoniou-consulting.com>
Cc: Ye Li <ye.li@nxp.com>
---
 drivers/mmc/mmc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index ba54b19c14..4d9871d69f 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -819,11 +819,11 @@ static int __mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value,
 		return ret;
 
 	/*
-	 * In cases when not allowed to poll by using CMD13 or because we aren't
+	 * In cases when neiter allowed to poll by using CMD13 nor we are
 	 * capable of polling by using mmc_wait_dat0, then rely on waiting the
 	 * stated timeout to be sufficient.
 	 */
-	if (ret == -ENOSYS || !send_status) {
+	if (ret == -ENOSYS && !send_status) {
 		mdelay(timeout_ms);
 		return 0;
 	}
-- 
2.11.0

Re: [PATCH 1/1] mmc: Fix mmc_switch excessive timeout

[Marek Behún]

Reviewed-by: Marek Behún <marek.behun@nic.cz>
Tested-by: Marek Behún <marek.behun@nic.cz>

This fixes a bug introduced in commit 3f4e52fc9d81
  https://source.denx.de/u-boot/u-boot/-/commit/3f4e52fc9d81e95ee90f6be7b05ca62fc8c7c1e3
and it is incorrect. It caused the mmc initialization to take 4 seconds
(previously it was <0.1s).

The code in Linux also uses &&, and the comment says:
  If the host doesn't support HW polling via the ->card_busy() ops and
  when it's not allowed to poll by using CMD13, then we need to rely on
  waiting the stated timeout to be sufficient.

See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/mmc/core/mmc_ops.c?h=v5.15-rc5#n598

Peng, could we get this merged ASAP? :)

Marek