mmc: sdhci: Add support for O2 hardware tuning

Add hardware tuning function instead of software tuning because O2/Bayhub
SD host controller support hardware tuning.

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>

diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
index 7b37713d8826f1ff6d6399e4eab9d5a8952c316b..98e26ee1a9728391f83e61400e2c8eeb5a5f8f37 100644 (file)
--- a/drivers/mmc/host/sdhci-pci-o2micro.c
+++ b/drivers/mmc/host/sdhci-pci-o2micro.c
@@ -17,6 +17,9 @@
  */
 
 #include <linux/pci.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/delay.h>
 
 #include "sdhci.h"
 #include "sdhci-pci.h"
@@ -55,6 +58,82 @@
 
 #define O2_SD_VENDOR_SETTING   0x110
 #define O2_SD_VENDOR_SETTING2  0x1C8
+#define O2_SD_HW_TUNING_DISABLE        BIT(4)
+
+static void sdhci_o2_set_tuning_mode(struct sdhci_host *host)
+{
+       u16 reg;
+
+       /* enable hardware tuning */
+       reg = sdhci_readw(host, O2_SD_VENDOR_SETTING);
+       reg &= ~O2_SD_HW_TUNING_DISABLE;
+       sdhci_writew(host, reg, O2_SD_VENDOR_SETTING);
+}
+
+static void __sdhci_o2_execute_tuning(struct sdhci_host *host, u32 opcode)
+{
+       int i;
+
+       sdhci_send_tuning(host, MMC_SEND_TUNING_BLOCK_HS200);
+
+       for (i = 0; i < 150; i++) {
+               u16 ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+
+               if (!(ctrl & SDHCI_CTRL_EXEC_TUNING)) {
+                       if (ctrl & SDHCI_CTRL_TUNED_CLK) {
+                               host->tuning_done = true;
+                               return;
+                       }
+                       pr_warn("%s: HW tuning failed !\n",
+                               mmc_hostname(host->mmc));
+                       break;
+               }
+
+               mdelay(1);
+       }
+
+       pr_info("%s: Tuning failed, falling back to fixed sampling clock\n",
+               mmc_hostname(host->mmc));
+       sdhci_reset_tuning(host);
+}
+
+static int sdhci_o2_execute_tuning(struct mmc_host *mmc, u32 opcode)
+{
+       struct sdhci_host *host = mmc_priv(mmc);
+       int current_bus_width = 0;
+
+       /*
+        * This handler only implements the eMMC tuning that is specific to
+        * this controller.  Fall back to the standard method for other TIMING.
+        */
+       if (host->timing != MMC_TIMING_MMC_HS200)
+               return sdhci_execute_tuning(mmc, opcode);
+
+       if (WARN_ON(opcode != MMC_SEND_TUNING_BLOCK_HS200))
+               return -EINVAL;
+
+       /*
+        * o2 sdhci host didn't support 8bit emmc tuning
+        */
+       if (mmc->ios.bus_width == MMC_BUS_WIDTH_8) {
+               current_bus_width = mmc->ios.bus_width;
+               sdhci_set_bus_width(host, MMC_BUS_WIDTH_4);
+       }
+
+       sdhci_o2_set_tuning_mode(host);
+
+       sdhci_start_tuning(host);
+
+       __sdhci_o2_execute_tuning(host, opcode);
+
+       sdhci_end_tuning(host);
+
+       if (current_bus_width == MMC_BUS_WIDTH_8)
+               sdhci_set_bus_width(host, current_bus_width);
+
+       host->flags &= ~SDHCI_HS400_TUNING;
+       return 0;
+}
 
 static void o2_pci_set_baseclk(struct sdhci_pci_chip *chip, u32 value)
 {
@@ -215,6 +294,8 @@ int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
                        }
                }
 
+               host->mmc_host_ops.execute_tuning = sdhci_o2_execute_tuning;
+
                if (chip->pdev->device != PCI_DEVICE_ID_O2_FUJIN2)
                        break;
                /* set dll watch dog timer */

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index bcea179a8d707ce99cabd9042d9b90034bc90ca5..1b3fbd9bd5c5b57c451acf44e186b0736b6ed13e 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1029,7 +1029,9 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
        if (data == NULL) {
                if (host->quirks2 &
                        SDHCI_QUIRK2_CLEAR_TRANSFERMODE_REG_BEFORE_CMD) {
-                       sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE);
+                       /* must not clear SDHCI_TRANSFER_MODE when tuning */
+                       if (cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200)
+                               sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE);
                } else {
                /* clear Auto CMD settings for no data CMDs */
                        mode = sdhci_readw(host, SDHCI_TRANSFER_MODE);