[U-Boot] [PATCH] mmc: Remove return from mmc_init for non SD 2.0 compatible cards.
Cards which are not compatible with SD 2.0 standard, cat return response for CMD8 command, but it will be invalid in terms of SD 2.0. We should accept this case as admissible.
Signed-off-by: Yauhen Kharuzhy jekhor@gmail.com --- drivers/mmc/mmc.c | 4 ---- 1 files changed, 0 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 596e052..b284030 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -870,10 +870,6 @@ int mmc_init(struct mmc *mmc) /* Test for SD version 2 */ err = mmc_send_if_cond(mmc);
- /* If we got an error other than timeout, we bail */ - if (err && err != TIMEOUT) - return err; - /* Now try to get the SD card's operating condition */ err = sd_send_op_cond(mmc);
On Thu, May 7, 2009 at 5:08 AM, Yauhen Kharuzhy jekhor@gmail.com wrote:
Cards which are not compatible with SD 2.0 standard, cat return response for CMD8 command, but it will be invalid in terms of SD 2.0. We should accept this case as admissible.
Signed-off-by: Yauhen Kharuzhy jekhor@gmail.com
You've got a typo in the description on a key word, "cat". Is it can't? can?
I'm not convinced that this patch is valid. My understanding is that if a card receives a command it does not understand, it should not respond. Thus, if it responds with an error, it's an actual error. Are you saying that some cards respond to cmd 8 that don't implement 2.0? Because that would not totally surprise me, but would violate not just 2.0, but 1.x, as CMD8 is reserved. MMC cards should also not respond to CMD8 at this stage in initialization, as they are in the wrong state...
Andy
On Thu, May 07, 2009 at 03:13:40PM -0500, Andy Fleming wrote:
On Thu, May 7, 2009 at 5:08 AM, Yauhen Kharuzhy jekhor@gmail.com wrote:
Cards which are not compatible with SD 2.0 standard, cat return response for CMD8 command, but it will be invalid in terms of SD 2.0. We should accept this case as admissible.
Signed-off-by: Yauhen Kharuzhy jekhor@gmail.com
You've got a typo in the description on a key word, "cat". Is it can't? can?
I am sorry, yes, it is 'can'.
I'm not convinced that this patch is valid. My understanding is that if a card receives a command it does not understand, it should not respond. Thus, if it responds with an error, it's an actual error. Are you saying that some cards respond to cmd 8 that don't implement 2.0? Because that would not totally surprise me, but would violate not just 2.0, but 1.x, as CMD8 is reserved. MMC cards should also not respond to CMD8 at this stage in initialization, as they are in the wrong state...
I just to try all my cards with my device, and every card responds to CMD8. Probably, this is bug in the implementation of the my MMC host driver (for Ingenic JZ4740 SoC). I compared card initialization procedure with Linux kernel's one and found that any error is ignored in it and means that the card is not SD 2.0 compatible.
I will re-check the host controller driver for timeout handling, but it seems clear.
On Thu, May 7, 2009 at 4:52 PM, Yauhen Kharuzhy jekhor@gmail.com wrote:
On Thu, May 07, 2009 at 03:13:40PM -0500, Andy Fleming wrote:
On Thu, May 7, 2009 at 5:08 AM, Yauhen Kharuzhy jekhor@gmail.com
wrote:
Cards which are not compatible with SD 2.0 standard, cat return
response
for CMD8 command, but it will be invalid in terms of SD 2.0. We should accept this case as admissible.
Signed-off-by: Yauhen Kharuzhy jekhor@gmail.com
Applied to HEAD, with minor commit message modifications
Andy
participants (2)
-
Andy Fleming -
Yauhen Kharuzhy