Hi, Alex. On 08/13/2014 10:27 PM, Alex Lemberg wrote: > Hi, > > HS200 & HS400 mode is not supported during boot operation, but I think this specific change > will prevent any boot operation or access to boot partition on all hosts with HS200 & HS400 capabilities in general, > even in case then the eMMC card is DDR52 type. Right, even if host capabilities is supported HS200 & HS400, card couldn't support them. then maybe work the DDR50 or other mode. > The actual bus clock speed need to be checked in order to prevent/allow boot operation, but not the host capabilities. Exactly right. :) As you mentioned, this patch is not perfect. but boot_part_access() called before set to final busmode. I will consider it, but i think good that don't access at boot partition when mode is hs200/hs400 mode. > > As for regular R/W access to boot partition, as far as I see from the JEDEC spec - it can work in HS200 & HS400 modes, so no change is required. Well, it can work HS200 & HS400 mode at boot partition? i didn't think so. > Please correct me if I wrong. Thanks for comments. Best Regards, Jaehoon Chung > > Thanks, > Alex > > > >> -----Original Message----- >> From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- >> owner@xxxxxxxxxxxxxxx] On Behalf Of Jaehoon Chung >> Sent: Wednesday, August 13, 2014 7:46 AM >> To: linux-mmc >> Cc: Chris Ball; Ulf Hansson; Jaehoon Chung >> Subject: [PATCH] mmc: host: don't access at boot partition when mode is >> HS200/HS400. >> >> HS200/HS400 mode is not supported during boot operation. >> >> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx> >> --- >> include/linux/mmc/host.h | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index >> 7960424..ce5db96 100644 >> --- a/include/linux/mmc/host.h >> +++ b/include/linux/mmc/host.h >> @@ -445,6 +445,10 @@ static inline int mmc_host_cmd23(struct mmc_host >> *host) >> >> static inline int mmc_boot_partition_access(struct mmc_host *host) { >> + /* HS200 & HS400 mode is not supported during boot operation */ >> + if (host->caps2 & (MMC_CAP2_HS200 | MMC_CAP2_HS400)) >> + return 0; >> + >> return !(host->caps2 & MMC_CAP2_BOOTPART_NOACC); } >> >> -- >> 1.7.9.5 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the >> body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at >> http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
