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>

1 files changed, 27 insertions, 0 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