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. The actual bus clock speed need to be checked in order to prevent/allow boot operation, but not the host capabilities.
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. Please correct me if I wrong. Thanks, Alex > -----Original Message----- > From: [email protected] [mailto:linux-mmc- > [email protected]] 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 <[email protected]> > --- > 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 [email protected] 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
