@@ -1043,6 +1043,7 @@ static int mmc_select_hs_ddr(struct mmc_card *card)
static int mmc_select_hs400(struct mmc_card *card)
{
struct mmc_host *host = card->host;
+ unsigned int max_dtr;
int err = 0;
u8 val;
@@ -1053,13 +1054,11 @@ static int mmc_select_hs400(struct mmc_card *card)
host->ios.bus_width == MMC_BUS_WIDTH_8))
return 0;
- /*
- * Before switching to dual data rate operation for HS400,
- * it is required to convert from HS200 mode to HS mode.
- */
- mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
- mmc_set_bus_speed(card);
+ /* Reduce frequency to HS frequency */
+ max_dtr = card->ext_csd.hs_max_dtr;
+ mmc_set_clock(host, max_dtr);
+ /* Switch card to HS mode */
val = EXT_CSD_TIMING_HS |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
@@ -1072,6 +1071,9 @@ static int mmc_select_hs400(struct mmc_card *card)
return err;
}
+ /* Set host controller to HS timing */
+ mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_BUS_WIDTH,
EXT_CSD_DDR_BUS_WIDTH_8,
This is a note to let you know that I have just added a patch titled mmc: mmc: Fix HS setting in mmc_select_hs400() to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From c50e73473e35418d0f93fbf160ab29924bb91b64 Mon Sep 17 00:00:00 2001 From: Adrian Hunter <adrian.hunter@intel.com> Date: Wed, 28 Oct 2015 14:25:41 +0200 Subject: mmc: mmc: Fix HS setting in mmc_select_hs400() commit 51b12f7764fa8bb464cbd0f7bbd3a408d21ade16 upstream. mmc_select_hs400() begins with the card and host in HS200 mode. Therefore, any commands sent to the card should use HS200 timing. It is incorrect to set the host to High Speed (HS) timing before sending the switch command. Doing so is unreliable because the timing parameters for HS mode are tighter than the timing parameters for HS200 mode. Thus the HS timings should be set only after the card has switched mode. However, it is not unreasonable first to reduce the frequency to the HS mode frequency, which should make the switch command and subsequent CMD13 commands more reliable. This patch does that. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Alim Akhtar <alim.akhtar@samsung.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/mmc/core/mmc.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) -- 1.9.1