mmc: sd: add support for driver type selection

This patch adds support for setting driver strength during UHS-I
initialization procedure. Since UHS-I cards set S18A (bit 24) in
response to ACMD41, we use this as a base for UHS-I initialization.
We modify the parameter list of mmc_sd_get_cid() so that we can
save the ROCR from ACMD41 to check whether bit 24 is set.

We decide whether the Host Controller supports A, C, or D driver
type depending on the Capabilities register. Driver type B is
suported by default. We then set the appropriate driver type for
the card using CMD6 mode 1. As per Host Controller spec v3.00, we
set driver type for the host only if Preset Value Enable in the
Host Control2 register is not set. SDHCI_HOST_CONTROL has been
renamed to SDHCI_HOST_CONTROL1 to conform to the spec.

Tested by Zhangfei Gao with a Toshiba uhs card and general hs card,
on mmp2 in SDMA mode.

Signed-off-by: Arindam Nath <arindam.nath@amd.com>
Reviewed-by: Philip Rakity <prakity@marvell.com>
Tested-by: Philip Rakity <prakity@marvell.com>
Acked-by: Zhangfei Gao <zhangfei.gao@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 37 insertions, 1 deletions

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 4e2031449a23..8072e16d6d46 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1245,6 +1245,25 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
         sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
 
+        if (host->version >= SDHCI_SPEC_300) {
+                u16 ctrl_2;
+
+                ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+                if (!(ctrl_2 & SDHCI_CTRL_PRESET_VAL_ENABLE)) {
+                        /*
+                         * We only need to set Driver Strength if the
+                         * preset value enable is not set.
+                         */
+                        ctrl_2 &= ~SDHCI_CTRL_DRV_TYPE_MASK;
+                        if (ios->drv_type == MMC_SET_DRIVER_TYPE_A)
+                                ctrl_2 |= SDHCI_CTRL_DRV_TYPE_A;
+                        else if (ios->drv_type == MMC_SET_DRIVER_TYPE_C)
+                                ctrl_2 |= SDHCI_CTRL_DRV_TYPE_C;
+
+                        sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
+                }
+        }
+
         /*
          * Some (ENE) controllers go apeshit on some ios operation,
          * signalling timeout and CRC errors even on CMD0. Resetting
@@ -2086,6 +2105,14 @@ int sdhci_add_host(struct sdhci_host *host)
         if (caps[1] & SDHCI_SUPPORT_DDR50)
                 mmc->caps |= MMC_CAP_UHS_DDR50;
 
+        /* Driver Type(s) (A, C, D) supported by the host */
+        if (caps[1] & SDHCI_DRIVER_TYPE_A)
+                mmc->caps |= MMC_CAP_DRIVER_TYPE_A;
+        if (caps[1] & SDHCI_DRIVER_TYPE_C)
+                mmc->caps |= MMC_CAP_DRIVER_TYPE_C;
+        if (caps[1] & SDHCI_DRIVER_TYPE_D)
+                mmc->caps |= MMC_CAP_DRIVER_TYPE_D;
+
         ocr_avail = 0;
         /*
          * According to SD Host Controller spec v3.00, if the Host System
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 5cba2fea46e0..667bf8874be7 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -71,7 +71,7 @@
 #define  SDHCI_DATA_LVL_MASK    0x00F00000
 #define   SDHCI_DATA_LVL_SHIFT  20
 
-#define SDHCI_HOST_CONTROL      0x28
+#define SDHCI_HOST_CONTROL      0x28
 #define  SDHCI_CTRL_LED         0x01
 #define  SDHCI_CTRL_4BITBUS     0x02
 #define  SDHCI_CTRL_HISPD       0x04
@@ -150,6 +150,12 @@
 
 #define SDHCI_HOST_CONTROL2             0x3E
 #define  SDHCI_CTRL_VDD_180             0x0008
+#define  SDHCI_CTRL_DRV_TYPE_MASK       0x0030
+#define   SDHCI_CTRL_DRV_TYPE_B         0x0000
+#define   SDHCI_CTRL_DRV_TYPE_A         0x0010
+#define   SDHCI_CTRL_DRV_TYPE_C         0x0020
+#define   SDHCI_CTRL_DRV_TYPE_D         0x0030
+#define  SDHCI_CTRL_PRESET_VAL_ENABLE   0x8000
 
 #define SDHCI_CAPABILITIES      0x40
 #define  SDHCI_TIMEOUT_CLK_MASK 0x0000003F
@@ -173,6 +179,9 @@
 #define  SDHCI_SUPPORT_SDR50    0x00000001
 #define  SDHCI_SUPPORT_SDR104   0x00000002
 #define  SDHCI_SUPPORT_DDR50    0x00000004
+#define  SDHCI_DRIVER_TYPE_A    0x00000010
+#define  SDHCI_DRIVER_TYPE_C    0x00000020
+#define  SDHCI_DRIVER_TYPE_D    0x00000040
 
 #define SDHCI_CAPABILITIES_1    0x44