Add support for two more DT bindings, which stem from the need to
implement below real-life requirement shared by eMMC vendor:
---snip---
Use "drive strength" value of 4 or 1 for HS400 or 0 for HS200.
---snip---
Inspire from [Y] and [Z] during implementation and testing (H3ULCB-KF).
Below decision matrix is intended as function of user's input:
[0] [2] [4]
[0] hs200:[0] hs200:[2] hs200:[0]
hs400:[0] hs400:[0] hs400:[4]
[2] hs200:[2] hs200:[2] hs200:[2]
hs400:[0] hs400:[R] hs400:[4]
[4] hs200:[0] hs200:[2] hs200:[R]
hs400:[4] hs400:[4] hs400:[4]
[0] "fixed-emmc-driver-type"
[2] "fixed-emmc-driver-type-hs200"
[4] "fixed-emmc-driver-type-hs400"
[R] RAW/ECSD drive strength as implemented in
commit cc4f414c885cd0 ("mmc: mmc: Add driver strength selection")
[Y] commit 6186d06c519e21 ("mmc: parse new binding for eMMC fixed driver type")
[Z] https://www.elinux.org/Tests:eMMC-fixed-drive-strength
Cc: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
---
drivers/mmc/core/host.c | 4 ++++
drivers/mmc/core/mmc.c | 19 ++++++++++++++++---
include/linux/mmc/host.h | 2 ++
3 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 54abfdfc69ba..2a3d3b542e0d 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -336,6 +336,8 @@ int mmc_of_parse(struct mmc_host *host)
/* Must be after "non-removable" check */
mmc_of_read_drv_type(host, "fixed-emmc-driver-type", &host->fixed_drv_type);
+ mmc_of_read_drv_type(host, "fixed-emmc-driver-type-hs200", &host->fixed_drv_type_hs200);
+ mmc_of_read_drv_type(host, "fixed-emmc-driver-type-hs400", &host->fixed_drv_type_hs400);
host->dsr_req = !device_property_read_u32(dev, "dsr", &host->dsr);
if (host->dsr_req && (host->dsr & ~0xffff)) {
@@ -455,6 +457,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
host->max_blk_count = PAGE_SIZE / 512;
host->fixed_drv_type = -EINVAL;
+ host->fixed_drv_type_hs200 = -EINVAL;
+ host->fixed_drv_type_hs400 = -EINVAL;
host->ios.power_delay_ms = 10;
return host;
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index c8804895595f..89e6fb9aedeb 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -62,6 +62,8 @@ static const unsigned int taac_mant[] = {
__res & __mask; \
})
+static void mmc_select_driver_type(struct mmc_card *card, int timing);
+
/*
* Given the decoded CSD structure, decode the raw CID to our CID structure.
*/
@@ -1192,6 +1194,8 @@ static int mmc_select_hs400(struct mmc_card *card)
return err;
}
+ mmc_select_driver_type(card, EXT_CSD_TIMING_HS400);
+
/* Switch card to HS400 */
val = EXT_CSD_TIMING_HS400 |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
@@ -1270,6 +1274,8 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
if (err)
goto out_err;
+ mmc_select_driver_type(card, EXT_CSD_TIMING_HS200);
+
/* Switch HS to HS200 */
val = EXT_CSD_TIMING_HS200 |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
@@ -1304,10 +1310,17 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
return err;
}
-static void mmc_select_driver_type(struct mmc_card *card)
+static void mmc_select_driver_type(struct mmc_card *card, int timing)
{
int card_drv_type, drive_strength, drv_type = 0;
int fixed_drv_type = card->host->fixed_drv_type;
+ int fixed_drv_type_hs200 = card->host->fixed_drv_type_hs200;
+ int fixed_drv_type_hs400 = card->host->fixed_drv_type_hs400;
+
+ if (fixed_drv_type_hs200 >= 0 && timing == EXT_CSD_TIMING_HS200)
+ fixed_drv_type = fixed_drv_type_hs200;
+ else if (fixed_drv_type_hs400 >= 0 && timing == EXT_CSD_TIMING_HS400)
+ fixed_drv_type = fixed_drv_type_hs400;
card_drv_type = card->ext_csd.raw_driver_strength |
mmc_driver_type_mask(0);
@@ -1385,7 +1398,7 @@ static int mmc_select_hs400es(struct mmc_card *card)
goto out_err;
}
- mmc_select_driver_type(card);
+ mmc_select_driver_type(card, EXT_CSD_TIMING_HS400);
/* Switch card to HS400 */
val = EXT_CSD_TIMING_HS400 |
@@ -1445,7 +1458,7 @@ static int mmc_select_hs200(struct mmc_card *card)
if (err)
return err;
- mmc_select_driver_type(card);
+ mmc_select_driver_type(card, EXT_CSD_TIMING_HS200);
/*
* Set the bus width(4 or 8) with host's support and
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index ba703384bea0..6960ba98810a 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -371,6 +371,8 @@ struct mmc_host {
#define MMC_CAP2_MERGE_CAPABLE (1 << 26) /* Host can merge a segment over the segment size */
int fixed_drv_type; /* fixed driver type for non-removable media */
+ int fixed_drv_type_hs200; /* HS200-specific fixed_drv_type */
+ int fixed_drv_type_hs400; /* HS400-specific fixed_drv_type */
mmc_pm_flag_t pm_caps; /* supported pm features */
--
2.23.0
