mmc: meson-gx: add basic tuning for rx clock phase

[karo-tx-linux.git] / drivers / mmc / host / meson-gx-mmc.c

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 3a6e51c8c5d2d7057c3ac5a46aa93e458709e03a..eb5ee68dbd469fd5f8f1eef9a8bc05a930bf3b22 100644 (file)
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -349,6 +349,31 @@ static int meson_mmc_clk_init(struct meson_host *host)
        return ret;
 }
 
+static void meson_mmc_set_tuning_params(struct mmc_host *mmc)
+{
+       struct meson_host *host = mmc_priv(mmc);
+       u32 regval;
+
+       /* stop clock */
+       regval = readl(host->regs + SD_EMMC_CFG);
+       regval |= CFG_STOP_CLOCK;
+       writel(regval, host->regs + SD_EMMC_CFG);
+
+       regval = readl(host->regs + SD_EMMC_CLOCK);
+       regval &= ~CLK_CORE_PHASE_MASK;
+       regval |= FIELD_PREP(CLK_CORE_PHASE_MASK, host->tp.core_phase);
+       regval &= ~CLK_TX_PHASE_MASK;
+       regval |= FIELD_PREP(CLK_TX_PHASE_MASK, host->tp.tx_phase);
+       regval &= ~CLK_RX_PHASE_MASK;
+       regval |= FIELD_PREP(CLK_RX_PHASE_MASK, host->tp.rx_phase);
+       writel(regval, host->regs + SD_EMMC_CLOCK);
+
+       /* start clock */
+       regval = readl(host->regs + SD_EMMC_CFG);
+       regval &= ~CFG_STOP_CLOCK;
+       writel(regval, host->regs + SD_EMMC_CFG);
+}
+
 static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
        struct meson_host *host = mmc_priv(mmc);
@@ -682,6 +707,29 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
+static int meson_mmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
+{
+       struct meson_host *host = mmc_priv(mmc);
+       struct meson_tuning_params tp_old = host->tp;
+       int ret = -EINVAL, i, cmd_error;
+
+       dev_info(mmc_dev(mmc), "(re)tuning...\n");
+
+       for (i = CLK_PHASE_0; i <= CLK_PHASE_270; i++) {
+               host->tp.rx_phase = i;
+               /* exclude the active parameter set if retuning */
+               if (!memcmp(&tp_old, &host->tp, sizeof(tp_old)) &&
+                   mmc->doing_retune)
+                       continue;
+               meson_mmc_set_tuning_params(mmc);
+               ret = mmc_send_tuning(mmc, opcode, &cmd_error);
+               if (!ret)
+                       break;
+       }
+
+       return ret;
+}
+
 /*
  * NOTE: we only need this until the GPIO/pinctrl driver can handle
  * interrupts.  For now, the MMC core will use this for polling.
@@ -712,6 +760,7 @@ static const struct mmc_host_ops meson_mmc_ops = {
        .request        = meson_mmc_request,
        .set_ios        = meson_mmc_set_ios,
        .get_cd         = meson_mmc_get_cd,
+       .execute_tuning = meson_mmc_execute_tuning,
 };
 
 static int meson_mmc_probe(struct platform_device *pdev)