Implement the .platform_execute_tuning for Sophgo CV1800B and SG200X.
Some code is borrowed from sdhci-esdhc-imx.c. The tuning result is
similar as the one of SoC vendor's SDK.
Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
Since v1:
- use usleep_range() instead of mdelay() as suggested by Adrian
drivers/mmc/host/sdhci-of-dwcmshc.c | 112 ++++++++++++++++++++++++++++
1 file changed, 112 insertions(+)
diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
index ab4b964d4058..7b55acd9830c 100644
--- a/drivers/mmc/host/sdhci-of-dwcmshc.c
+++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
@@ -66,6 +66,10 @@
#define CV18XX_SDHCI_PHY_CONFIG 0x4c
#define CV18XX_PHY_TX_BPS BIT(0)
+#define CV18XX_TUNE_MAX 128
+#define CV18XX_TUNE_STEP 1
+#define CV18XX_RETRY_TUNING_MAX 50
+
/* Rockchip specific Registers */
#define DWCMSHC_EMMC_DLL_CTRL 0x800
#define DWCMSHC_EMMC_DLL_RXCLK 0x804
@@ -685,6 +689,113 @@ static void cv18xx_sdhci_reset(struct sdhci_host *host, u8 mask)
sdhci_writel(host, val, priv->vendor_specific_area1 + CV18XX_SDHCI_PHY_TX_RX_DLY);
}
+static void cv18xx_sdhci_set_tap(struct sdhci_host *host, int tap)
+{
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+ u16 clk;
+ u32 val;
+
+ clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+ clk &= ~SDHCI_CLOCK_CARD_EN;
+ sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+
+ val = sdhci_readl(host, priv->vendor_specific_area1 + CV18XX_SDHCI_MSHC_CTRL);
+ val &= ~CV18XX_LATANCY_1T;
+ sdhci_writel(host, val, priv->vendor_specific_area1 + CV18XX_SDHCI_MSHC_CTRL);
+
+ val = (FIELD_PREP(CV18XX_PHY_TX_DLY_MSK, 0) |
+ FIELD_PREP(CV18XX_PHY_TX_SRC_MSK, CV18XX_PHY_TX_SRC_INVERT_CLK_TX) |
+ FIELD_PREP(CV18XX_PHY_RX_DLY_MSK, tap));
+ sdhci_writel(host, val, priv->vendor_specific_area1 + CV18XX_SDHCI_PHY_TX_RX_DLY);
+
+ sdhci_writel(host, 0, priv->vendor_specific_area1 + CV18XX_SDHCI_PHY_CONFIG);
+
+ clk |= SDHCI_CLOCK_CARD_EN;
+ sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+ usleep_range(1000, 2000);
+}
+
+static int cv18xx_retry_tuning(struct mmc_host *mmc, u32 opcode, int *cmd_error)
+{
+ int ret, retry = 0;
+
+ while (retry < CV18XX_RETRY_TUNING_MAX) {
+ ret = mmc_send_tuning(mmc, opcode, NULL);
+ if (ret)
+ return ret;
+ retry++;
+ }
+
+ return 0;
+}
+
+static void cv18xx_sdhci_post_tuning(struct sdhci_host *host)
+{
+ u32 val;
+
+ val = sdhci_readl(host, SDHCI_INT_STATUS);
+ val |= SDHCI_INT_DATA_AVAIL;
+ sdhci_writel(host, val, SDHCI_INT_STATUS);
+
+ sdhci_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
+}
+
+static int cv18xx_sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
+{
+ int min, max, avg, ret;
+ int win_length, target_min, target_max, target_win_length;
+
+ min = max = 0;
+ target_win_length = 0;
+
+ sdhci_reset_tuning(host);
+
+ while (max < CV18XX_TUNE_MAX) {
+ /* find the mininum delay first which can pass tuning */
+ while (min < CV18XX_TUNE_MAX) {
+ cv18xx_sdhci_set_tap(host, min);
+ if (!cv18xx_retry_tuning(host->mmc, opcode, NULL))
+ break;
+ min += CV18XX_TUNE_STEP;
+ }
+
+ /* find the maxinum delay which can not pass tuning */
+ max = min + CV18XX_TUNE_STEP;
+ while (max < CV18XX_TUNE_MAX) {
+ cv18xx_sdhci_set_tap(host, max);
+ if (cv18xx_retry_tuning(host->mmc, opcode, NULL)) {
+ max -= CV18XX_TUNE_STEP;
+ break;
+ }
+ max += CV18XX_TUNE_STEP;
+ }
+
+ win_length = max - min + 1;
+ /* get the largest pass window */
+ if (win_length > target_win_length) {
+ target_win_length = win_length;
+ target_min = min;
+ target_max = max;
+ }
+
+ /* continue to find the next pass window */
+ min = max + CV18XX_TUNE_STEP;
+ }
+
+ cv18xx_sdhci_post_tuning(host);
+
+ /* use average delay to get the best timing */
+ avg = (target_min + target_max) / 2;
+ cv18xx_sdhci_set_tap(host, avg);
+ ret = mmc_send_tuning(host->mmc, opcode, NULL);
+
+ dev_dbg(mmc_dev(host->mmc), "tuning %s at 0x%x ret %d\n",
+ ret ? "failed" : "passed", avg, ret);
+
+ return ret;
+}
+
static const struct sdhci_ops sdhci_dwcmshc_ops = {
.set_clock = sdhci_set_clock,
.set_bus_width = sdhci_set_bus_width,
@@ -721,6 +832,7 @@ static const struct sdhci_ops sdhci_dwcmshc_cv18xx_ops = {
.get_max_clock = dwcmshc_get_max_clock,
.reset = cv18xx_sdhci_reset,
.adma_write_desc = dwcmshc_adma_write_desc,
+ .platform_execute_tuning = cv18xx_sdhci_execute_tuning,
};
static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = {
--
2.43.0
