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

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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Adrian Hunter authored and Ulf Hansson committed Jun 1, 2015
1 parent b097e07 commit cc4f414
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Showing 2 changed files with 41 additions and 7 deletions.
45 changes: 38 additions & 7 deletions drivers/mmc/core/mmc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1044,6 +1044,7 @@ 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
Expand All @@ -1059,8 +1060,10 @@ 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) {
Expand All @@ -1079,8 +1082,10 @@ 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) {
Expand Down Expand Up @@ -1119,6 +1124,7 @@ 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;
Expand All @@ -1128,8 +1134,10 @@ 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;
Expand Down Expand Up @@ -1158,10 +1166,11 @@ 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;

Expand All @@ -1183,6 +1192,23 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
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.
Expand All @@ -1194,6 +1220,7 @@ 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);
Expand All @@ -1205,14 +1232,18 @@ 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)
Expand Down
3 changes: 3 additions & 0 deletions include/linux/mmc/mmc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -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 */

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