[PATCH V3 10/15] mmc: core: Add support for HS400 re-tuning

Adrian Hunter
2015-02-04T13:37:08Z

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>
---

V3:
Remember to mmc_set_bus_speed(card) in mmc_hs400_to_hs200()

drivers/mmc/core/core.h | 2 ++
drivers/mmc/core/host.c | 17 ++++++++++
drivers/mmc/core/mmc.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 107 insertions(+)

diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index cfba3c0..e6f2de7 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -88,6 +88,8 @@ 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 221d46d..20354a5 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -322,6 +322,7 @@ 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 ||
@@ -332,8 +333,24 @@ 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 813b02a..03577be 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1083,6 +1083,94 @@ 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);
+}
+
+/* Caller must hold re-tuning */
+static int mmc_switch_status(struct mmc_card *card)
+{
+ u32 status;
+ int err;
+
+ err = mmc_send_status(card, &status);
+ if (err)
+ return err;
+
+ return mmc_switch_status_error(card->host, status);
+}
+
+int mmc_hs400_to_hs200(struct mmc_card *card)
+{
+ struct mmc_host *host = card->host;
+ bool send_status = true;
+ unsigned int max_dtr;
+ int err;
+
+ if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
+ send_status = false;
+
+ /* Reduce frequency to HS */
+ max_dtr = card->ext_csd.hs_max_dtr;
+ mmc_set_clock(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, send_status, true);
+ if (err)
+ goto out_err;
+
+ mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
+
+ if (!send_status) {
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;
+ }
+
+ /* 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,
+ true, send_status, true);
+ if (err)
+ goto out_err;
+
+ mmc_set_timing(host, MMC_TIMING_MMC_HS);
+
+ if (!send_status) {
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;
+ }
+
+ /* 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, send_status,
+ true);
+ if (err)
+ goto out_err;
+
+ mmc_set_timing(host, MMC_TIMING_MMC_HS200);
+
+ if (!send_status) {
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;
+ }
+
+ mmc_set_bus_speed(card);
+
+ return 0;
+
+out_err:
+ pr_err("%s: %s failed, error %d\n", mmc_hostname(card->host),
+ __func__, err);
+ return err;
+}
+
/*
* For device supporting HS200 mode, the following sequence
* should be done before executing the tuning process.
--
1.9.1