[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 --- 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); -- 1.6.2.4 ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH] mmc: Remove return from mmc_init for non SD 2.0 compatible cards.
On Thu, May 7, 2009 at 5:08 AM, Yauhen Kharuzhy 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 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 ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH] mmc: Remove return from mmc_init for non SD 2.0 compatible cards.
On Thu, May 07, 2009 at 03:13:40PM -0500, Andy Fleming wrote: > On Thu, May 7, 2009 at 5:08 AM, Yauhen Kharuzhy 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 > > > 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. -- Yauhen Kharuzhy jekhor _at_ gmail.com JID: j...@jabber.ru A: No Q: Should I quote below my post? ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH] mmc: Remove return from mmc_init for non SD 2.0 compatible cards.
On Thu, May 7, 2009 at 4:52 PM, Yauhen Kharuzhy 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 > 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 > Applied to HEAD, with minor commit message modifications Andy ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
