[PATCH V2 08/11] mmc: mmc: Add driver strength selection

Adrian Hunter
2015-02-06T12:15:10Z

Add the ability to set eMMC driver strength
for HS200 and HS400.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/core/mmc.c | 45 ++++++++++++++++++++++++++++++++++++++-------
include/linux/mmc/mmc.h | 3 +++
2 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 3222d4a..23cc737 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1033,6 +1033,7 @@ static int mmc_select_hs400(struct mmc_card *card)
{
struct mmc_host *host = card->host;
int err = 0;
+ u8 val;

/*
* HS400 mode requires 8-bit bus width
@@ -1048,8 +1049,10 @@ static int mmc_select_hs400(struct mmc_card *card)
mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
mmc_set_bus_speed(card);

+ val = EXT_CSD_TIMING_HS |
+ card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
+ EXT_CSD_HS_TIMING, val,
card->ext_csd.generic_cmd6_time,
true, true, true);
if (err) {
@@ -1068,8 +1071,10 @@ static int mmc_select_hs400(struct mmc_card *card)
return err;
}

+ val = EXT_CSD_TIMING_HS400 |
+ card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS400,
+ EXT_CSD_HS_TIMING, val,
card->ext_csd.generic_cmd6_time,
true, true, true);
if (err) {
@@ -1108,6 +1113,7 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
bool send_status = true;
unsigned int max_dtr;
int err;
+ u8 val;

if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
send_status = false;
@@ -1117,8 +1123,10 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
mmc_set_clock(host, max_dtr);

/* Switch HS400 to HS DDR */
+ val = EXT_CSD_TIMING_HS |
+ card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
- EXT_CSD_TIMING_HS, card->ext_csd.generic_cmd6_time,
+ val, card->ext_csd.generic_cmd6_time,
true, send_status, true);
if (err)
goto out_err;
@@ -1147,10 +1155,11 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
}

/* Switch HS to HS200 */
+ val = EXT_CSD_TIMING_HS200 |
+ card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
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);
+ val, card->ext_csd.generic_cmd6_time, true,
+ send_status, true);
if (err)
goto out_err;

@@ -1172,6 +1181,23 @@ out_err:
return err;
}

+static void mmc_select_driver_type(struct mmc_card *card)
+{
+ int card_drv_type, drive_strength, drv_type;
+
+ card_drv_type = card->ext_csd.raw_driver_strength |
+ mmc_driver_type_mask(0);
+
+ drive_strength = mmc_select_drive_strength(card,
+ card->ext_csd.hs200_max_dtr,
+ card_drv_type, &drv_type);
+
+ card->drive_strength = drive_strength;
+
+ if (drv_type)
+ mmc_set_driver_type(card->host, drv_type);
+}
+
/*
* For device supporting HS200 mode, the following sequence
* should be done before executing the tuning process.
@@ -1183,6 +1209,7 @@ static int mmc_select_hs200(struct mmc_card *card)
{
struct mmc_host *host = card->host;
int err = -EINVAL;
+ u8 val;

if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120);
@@ -1194,14 +1221,18 @@ static int mmc_select_hs200(struct mmc_card *card)
if (err)
goto err;

+ mmc_select_driver_type(card);
+
/*
* Set the bus width(4 or 8) with host's support and
* switch to HS200 mode if bus width is set successfully.
*/
err = mmc_select_bus_width(card);
if (!IS_ERR_VALUE(err)) {
+ val = EXT_CSD_TIMING_HS200 |
+ card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS200,
+ EXT_CSD_HS_TIMING, val,
card->ext_csd.generic_cmd6_time,
true, true, true);
if (!err)
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 4819cfb..15f2c4a 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -391,6 +391,7 @@ struct _mmc_csd {
#define EXT_CSD_TIMING_HS 1 /* High speed */
#define EXT_CSD_TIMING_HS200 2 /* HS200 */
#define EXT_CSD_TIMING_HS400 3 /* HS400 */
+#define EXT_CSD_DRV_STR_SHIFT 4 /* Driver Strength shift */

#define EXT_CSD_SEC_ER_EN BIT(0)
#define EXT_CSD_SEC_BD_BLK_EN BIT(2)
@@ -442,4 +443,6 @@ struct _mmc_csd {
#define MMC_SWITCH_MODE_CLEAR_BITS 0x02 /* Clear bits which are 1 in value */
#define MMC_SWITCH_MODE_WRITE_BYTE 0x03 /* Set target to value */

+#define mmc_driver_type_mask(n) (1 << (n))
+
#endif /* LINUX_MMC_MMC_H */
--
1.9.1