mmc: sdhci: Add support for O2 eMMC HS200 mode

When use eMMC as boot device, the eMMC signaling voltage is tied to 1.8v
fixed output voltage, bios can set o2 sd host controller PCI configuration
register 0x308 bit4 to 1 to let driver skip 3.3v signaling voltage and
direct use 1.8v singling voltage in eMMC initialize process.

Signed-off-by: ernest.zhang <ernest.zhang@bayhubtech.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
index 555970a29c94..ba59db6a126c 100644
--- a/drivers/mmc/host/sdhci-pci-o2micro.c
+++ b/drivers/mmc/host/sdhci-pci-o2micro.c
@@ -3,6 +3,7 @@
  *
  * Authors: Peter Guo <peter.guo@bayhubtech.com>
  *          Adam Lee <adam.lee@canonical.com>
+ *          Ernest Zhang <ernest.zhang@bayhubtech.com>
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -39,6 +40,7 @@
 #define O2_SD_MISC_CTRL4        0xFC
 #define O2_SD_TUNING_CTRL       0x300
 #define O2_SD_PLL_SETTING       0x304
+#define O2_SD_MISC_SETTING      0x308
 #define O2_SD_CLK_SETTING       0x328
 #define O2_SD_CAP_REG2          0x330
 #define O2_SD_CAP_REG0          0x334
@@ -184,6 +186,7 @@ int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
         struct sdhci_pci_chip *chip;
         struct sdhci_host *host;
         u32 reg;
+        int ret;
 
         chip = slot->chip;
         host = slot->host;
@@ -197,6 +200,21 @@ int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
                 if (reg & 0x1)
                         host->quirks |= SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12;
 
+                if (chip->pdev->device == PCI_DEVICE_ID_O2_SEABIRD0) {
+                        ret = pci_read_config_dword(chip->pdev,
+                                                    O2_SD_MISC_SETTING, &reg);
+                        if (ret)
+                                return -EIO;
+                        if (reg & (1 << 4)) {
+                                pr_info("%s: emmc 1.8v flag is set, force 1.8v signaling voltage\n",
+                                        mmc_hostname(host->mmc));
+                                host->flags &= ~SDHCI_SIGNALING_330;
+                                host->flags |= SDHCI_SIGNALING_180;
+                                host->mmc->caps2 |= MMC_CAP2_NO_SD;
+                                host->mmc->caps2 |= MMC_CAP2_NO_SDIO;
+                        }
+                }
+
                 if (chip->pdev->device != PCI_DEVICE_ID_O2_FUJIN2)
                         break;
                 /* set dll watch dog timer */