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>

9 files changed, 190 insertions, 30 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5005a6323165..61c6c0b8f0e0 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -984,6 +984,15 @@ void mmc_set_timing(struct mmc_host *host, unsigned int timing)
 }
 
 /*
+ * Select appropriate driver type for host.
+ */
+void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type)
+{
+        host->ios.drv_type = drv_type;
+        mmc_set_ios(host);
+}
+
+/*
  * Apply power to the MMC stack.  This is a two-stage process.
  * First, we enable power to the card without the clock running.
  * We then wait a bit for the power to stabilise.  Finally,
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 7745dea430b8..93f33973de39 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -43,6 +43,7 @@ void mmc_set_bus_width_ddr(struct mmc_host *host, unsigned int width,
 u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
 int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage);
 void mmc_set_timing(struct mmc_host *host, unsigned int timing);
+void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
 
 static inline void mmc_delay(unsigned int ms)
 {
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 8285842f19e9..5b7c99855635 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -400,6 +400,98 @@ out:
         return err;
 }
 
+static int sd_select_driver_type(struct mmc_card *card, u8 *status)
+{
+        int host_drv_type = 0, card_drv_type = 0;
+        int err;
+
+        /*
+         * If the host doesn't support any of the Driver Types A,C or D,
+         * default Driver Type B is used.
+         */
+        if (!(card->host->caps & (MMC_CAP_DRIVER_TYPE_A | MMC_CAP_DRIVER_TYPE_C
+            | MMC_CAP_DRIVER_TYPE_D)))
+                return 0;
+
+        if (card->host->caps & MMC_CAP_DRIVER_TYPE_A) {
+                host_drv_type = MMC_SET_DRIVER_TYPE_A;
+                if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_A)
+                        card_drv_type = MMC_SET_DRIVER_TYPE_A;
+                else if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_B)
+                        card_drv_type = MMC_SET_DRIVER_TYPE_B;
+                else if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_C)
+                        card_drv_type = MMC_SET_DRIVER_TYPE_C;
+        } else if (card->host->caps & MMC_CAP_DRIVER_TYPE_C) {
+                host_drv_type = MMC_SET_DRIVER_TYPE_C;
+                if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_C)
+                        card_drv_type = MMC_SET_DRIVER_TYPE_C;
+        } else if (!(card->host->caps & MMC_CAP_DRIVER_TYPE_D)) {
+                /*
+                 * If we are here, that means only the default driver type
+                 * B is supported by the host.
+                 */
+                host_drv_type = MMC_SET_DRIVER_TYPE_B;
+                if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_B)
+                        card_drv_type = MMC_SET_DRIVER_TYPE_B;
+                else if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_C)
+                        card_drv_type = MMC_SET_DRIVER_TYPE_C;
+        }
+
+        err = mmc_sd_switch(card, 1, 2, card_drv_type, status);
+        if (err)
+                return err;
+
+        if ((status[15] & 0xF) != card_drv_type) {
+                printk(KERN_WARNING "%s: Problem setting driver strength!\n",
+                        mmc_hostname(card->host));
+                return 0;
+        }
+
+        mmc_set_driver_type(card->host, host_drv_type);
+
+        return 0;
+}
+
+/*
+ * UHS-I specific initialization procedure
+ */
+static int mmc_sd_init_uhs_card(struct mmc_card *card)
+{
+        int err;
+        u8 *status;
+
+        if (!card->scr.sda_spec3)
+                return 0;
+
+        if (!(card->csd.cmdclass & CCC_SWITCH))
+                return 0;
+
+        status = kmalloc(64, GFP_KERNEL);
+        if (!status) {
+                printk(KERN_ERR "%s: could not allocate a buffer for "
+                        "switch capabilities.\n", mmc_hostname(card->host));
+                return -ENOMEM;
+        }
+
+        /* Set 4-bit bus width */
+        if ((card->host->caps & MMC_CAP_4_BIT_DATA) &&
+            (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
+                err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
+                if (err)
+                        goto out;
+
+                mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
+        }
+
+        /* Set the driver strength for the card */
+        err = sd_select_driver_type(card, status);
+
+out:
+        kfree(status);
+
+        return err;
+}
+
 MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
         card->raw_cid[2], card->raw_cid[3]);
 MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
@@ -448,10 +540,9 @@ struct device_type sd_type = {
 /*
  * Fetch CID from card.
  */
-int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
+int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
 {
         int err;
-        u32 rocr;
 
         /*
          * Since we're changing the OCR value, we seem to
@@ -485,7 +576,7 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
                 ocr |= SD_OCR_XPC;
 
 try_again:
-        err = mmc_send_app_op_cond(host, ocr, &rocr);
+        err = mmc_send_app_op_cond(host, ocr, rocr);
         if (err)
                 return err;
 
@@ -493,7 +584,8 @@ try_again:
          * In case CCS and S18A in the response is set, start Signal Voltage
          * Switch procedure. SPI mode doesn't support CMD11.
          */
-        if (!mmc_host_is_spi(host) && ((rocr & 0x41000000) == 0x41000000)) {
+        if (!mmc_host_is_spi(host) && rocr &&
+           ((*rocr & 0x41000000) == 0x41000000)) {
                 err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
                 if (err) {
                         ocr &= ~SD_OCR_S18R;
@@ -628,11 +720,12 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
         struct mmc_card *card;
         int err;
         u32 cid[4];
+        u32 rocr = 0;
 
         BUG_ON(!host);
         WARN_ON(!host->claimed);
 
-        err = mmc_sd_get_cid(host, ocr, cid);
+        err = mmc_sd_get_cid(host, ocr, cid, &rocr);
         if (err)
                 return err;
 
@@ -685,30 +778,37 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
         if (err)
                 goto free_card;
 
-        /*
-         * Attempt to change to high-speed (if supported)
-         */
-        err = mmc_sd_switch_hs(card);
-        if (err > 0)
-                mmc_sd_go_highspeed(card);
-        else if (err)
-                goto free_card;
-
-        /*
-         * Set bus speed.
-         */
-        mmc_set_clock(host, mmc_sd_get_max_clock(card));
-
-        /*
-         * Switch to wider bus (if supported).
-         */
-        if ((host->caps & MMC_CAP_4_BIT_DATA) &&
-                (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
-                err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
+        /* Initialization sequence for UHS-I cards */
+        if (rocr & SD_ROCR_S18A) {
+                err = mmc_sd_init_uhs_card(card);
                 if (err)
                         goto free_card;
+        } else {
+                /*
+                 * Attempt to change to high-speed (if supported)
+                 */
+                err = mmc_sd_switch_hs(card);
+                if (err > 0)
+                        mmc_sd_go_highspeed(card);
+                else if (err)
+                        goto free_card;
+
+                /*
+                 * Set bus speed.
+                 */
+                mmc_set_clock(host, mmc_sd_get_max_clock(card));
 
-                mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
+                /*
+                 * Switch to wider bus (if supported).
+                 */
+                if ((host->caps & MMC_CAP_4_BIT_DATA) &&
+                        (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
+                        err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
+                        if (err)
+                                goto free_card;
+
+                        mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
+                }
         }
 
         host->card = card;
diff --git a/drivers/mmc/core/sd.h b/drivers/mmc/core/sd.h
index 3d8800fa7600..4b34b24f3f76 100644
--- a/drivers/mmc/core/sd.h
+++ b/drivers/mmc/core/sd.h
@@ -5,7 +5,7 @@
 
 extern struct device_type sd_type;
 
-int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid);
+int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr);
 int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card);
 void mmc_decode_cid(struct mmc_card *card);
 int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 1e6095961500..4d0c15bfa514 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -369,8 +369,8 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
                 goto err;
         }
 
-        if (ocr & R4_MEMORY_PRESENT
-            && mmc_sd_get_cid(host, host->ocr & ocr, card->raw_cid) == 0) {
+        if ((ocr & R4_MEMORY_PRESENT) &&
+            mmc_sd_get_cid(host, host->ocr & ocr, card->raw_cid, NULL) == 0) {
                 card->type = MMC_TYPE_SD_COMBO;
 
                 if (oldcard && (oldcard->type != MMC_TYPE_SD_COMBO ||
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
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 56f4d9234a66..539327260dc1 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -83,6 +83,10 @@ struct sd_switch_caps {
         unsigned int            hs_max_dtr;
         unsigned int            sd3_bus_mode;
         unsigned int            sd3_drv_type;
+#define SD_DRIVER_TYPE_B        0x01
+#define SD_DRIVER_TYPE_A        0x02
+#define SD_DRIVER_TYPE_C        0x04
+#define SD_DRIVER_TYPE_D        0x08
         unsigned int            sd3_curr_limit;
 };
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index bde5a0b1c47e..949e4d525989 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -61,6 +61,13 @@ struct mmc_ios {
 
 #define MMC_SIGNAL_VOLTAGE_330  0
 #define MMC_SIGNAL_VOLTAGE_180  1
+
+        unsigned char   drv_type;               /* driver type (A, B, C, D) */
+
+#define MMC_SET_DRIVER_TYPE_B   0
+#define MMC_SET_DRIVER_TYPE_A   1
+#define MMC_SET_DRIVER_TYPE_C   2
+#define MMC_SET_DRIVER_TYPE_D   3
 };
 
 struct mmc_host_ops {
@@ -188,6 +195,9 @@ struct mmc_host {
 #define MMC_CAP_SET_XPC_330     (1 << 20)       /* Host supports >150mA current at 3.3V */
 #define MMC_CAP_SET_XPC_300     (1 << 21)       /* Host supports >150mA current at 3.0V */
 #define MMC_CAP_SET_XPC_180     (1 << 22)       /* Host supports >150mA current at 1.8V */
+#define MMC_CAP_DRIVER_TYPE_A   (1 << 23)       /* Host supports Driver Type A */
+#define MMC_CAP_DRIVER_TYPE_C   (1 << 24)       /* Host supports Driver Type C */
+#define MMC_CAP_DRIVER_TYPE_D   (1 << 25)       /* Host supports Driver Type D */
 
         mmc_pm_flag_t           pm_caps;        /* supported pm features */