[PATCH 11/13] mmc: core: Add support for HS400 re-tuning

Adrian Hunter
2014-12-05T17:43:46Z

HS400 re-tuning must be done in HS200 mode. Add
the ability to switch from HS400 mode to HS200
mode before re-tuning and switch back to HS400
after re-tuning.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/core/core.h | 2 ++
drivers/mmc/core/host.c | 17 +++++++++++++++++
drivers/mmc/core/mmc.c | 43 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 62 insertions(+)

diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 1b022c9..2a7d9219 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -84,6 +84,8 @@ void mmc_remove_card_debugfs(struct mmc_card *card);
void mmc_init_context_info(struct mmc_host *host);

int mmc_execute_tuning(struct mmc_card *card);
+int mmc_hs200_to_hs400(struct mmc_card *card);
+int mmc_hs400_to_hs200(struct mmc_card *card);

#endif

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index a4aa25b..62c4770 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -318,6 +318,7 @@ void mmc_retune_timer_stop(struct mmc_host *host)

int mmc_retune(struct mmc_host *host)
{
+ bool return_to_hs400 = false;
int err;

if (!host->need_retune || host->doing_retune || host->hold_retune ||
@@ -328,8 +329,24 @@ int mmc_retune(struct mmc_host *host)

host->doing_retune = 1;

+ if (host->ios.timing == MMC_TIMING_MMC_HS400) {
+ err = mmc_hs400_to_hs200(host->card);
+ if (err)
+ goto out;
+
+ return_to_hs400 = true;
+
+ if (host->ops->prepare_hs400_tuning)
+ host->ops->prepare_hs400_tuning(host, &host->ios);
+ }
+
err = mmc_execute_tuning(host->card);
+ if (err)
+ goto out;

+ if (return_to_hs400)
+ err = mmc_hs200_to_hs400(host->card);
+out:
host->doing_retune = 0;

return err;
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 7a913e6..167340c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1081,6 +1081,49 @@ static int mmc_select_hs400(struct mmc_card *card)
return 0;
}

+int mmc_hs200_to_hs400(struct mmc_card *card)
+{
+ return mmc_select_hs400(card);
+}
+
+int mmc_hs400_to_hs200(struct mmc_card *card)
+{
+ unsigned int max_dtr;
+ int err;
+
+ /* Reduce frequency to HS */
+ max_dtr = card->ext_csd.hs_max_dtr;
+ mmc_set_clock(card->host, max_dtr);
+
+ /* Switch HS400 to HS DDR */
+ err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
+ EXT_CSD_TIMING_HS, card->ext_csd.generic_cmd6_time,
+ true, true, true);
+ if (err)
+ return err;
+
+ mmc_set_timing(card->host, MMC_TIMING_MMC_DDR52);
+
+ /* Switch HS DDR to HS */
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BUS_WIDTH,
+ EXT_CSD_BUS_WIDTH_8, card->ext_csd.generic_cmd6_time);
+ if (err)
+ return err;
+
+ mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+
+ /* Switch HS to HS200 */
+ err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
+ EXT_CSD_TIMING_HS200,
+ card->ext_csd.generic_cmd6_time, true, true, true);
+ if (err)
+ return err;
+
+ mmc_set_timing(card->host, MMC_TIMING_MMC_HS200);
+
+ return err;
+}
+
/*
* For device supporting HS200 mode, the following sequence
* should be done before executing the tuning process.
--
1.9.1