mfd: mmc: rtsx: Change default tx phase

The default phase can meet most cards' requirement, but it is not the
optimal one. In some extreme situation, the rx phase point produced by
the following tuning process will drift quite a distance.
Before tuning UHS card, this patch will set a more proper initial tx
phase point, which is calculated from statistic data, and can achieve
a much better tx signal quality.

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 42 insertions, 16 deletions

diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index 82a35b9..fcb368e 100644
--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -56,7 +56,6 @@ struct realtek_pci_sdmmc {
 	bool			double_clk;
 	bool			eject;
 	bool			initial_mode;
-	bool			ddr_mode;
 	int			power_state;
 #define SDMMC_POWER_ON		1
 #define SDMMC_POWER_OFF		0
@@ -475,18 +474,24 @@ static void sd_normal_rw(struct realtek_pci_sdmmc *host,
 	kfree(buf);
 }
 
-static int sd_change_phase(struct realtek_pci_sdmmc *host, u8 sample_point)
+static int sd_change_phase(struct realtek_pci_sdmmc *host,
+		u8 sample_point, bool rx)
 {
 	struct rtsx_pcr *pcr = host->pcr;
 	int err;
 
-	dev_dbg(sdmmc_dev(host), "%s: sample_point = %d\n",
-			__func__, sample_point);
+	dev_dbg(sdmmc_dev(host), "%s(%s): sample_point = %d\n",
+			__func__, rx ? "RX" : "TX", sample_point);
 
 	rtsx_pci_init_cmd(pcr);
 
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CLK_CTL, CHANGE_CLK, CHANGE_CLK);
-	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, SD_VPRX_CTL, 0x1F, sample_point);
+	if (rx)
+		rtsx_pci_add_cmd(pcr, WRITE_REG_CMD,
+				SD_VPRX_CTL, 0x1F, sample_point);
+	else
+		rtsx_pci_add_cmd(pcr, WRITE_REG_CMD,
+				SD_VPTX_CTL, 0x1F, sample_point);
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, SD_VPCLK0_CTL, PHASE_NOT_RESET, 0);
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, SD_VPCLK0_CTL,
 			PHASE_NOT_RESET, PHASE_NOT_RESET);
@@ -602,7 +607,7 @@ static int sd_tuning_rx_cmd(struct realtek_pci_sdmmc *host,
 	int err;
 	u8 cmd[5] = {0};
 
-	err = sd_change_phase(host, sample_point);
+	err = sd_change_phase(host, sample_point, true);
 	if (err < 0)
 		return err;
 
@@ -664,7 +669,7 @@ static int sd_tuning_rx(struct realtek_pci_sdmmc *host, u8 opcode)
 		if (final_phase == 0xFF)
 			return -EINVAL;
 
-		err = sd_change_phase(host, final_phase);
+		err = sd_change_phase(host, final_phase, true);
 		if (err < 0)
 			return err;
 	} else {
@@ -833,14 +838,11 @@ static int sd_set_power_mode(struct realtek_pci_sdmmc *host,
 	return err;
 }
 
-static int sd_set_timing(struct realtek_pci_sdmmc *host,
-		unsigned char timing, bool *ddr_mode)
+static int sd_set_timing(struct realtek_pci_sdmmc *host, unsigned char timing)
 {
 	struct rtsx_pcr *pcr = host->pcr;
 	int err = 0;
 
-	*ddr_mode = false;
-
 	rtsx_pci_init_cmd(pcr);
 
 	switch (timing) {
@@ -857,8 +859,6 @@ static int sd_set_timing(struct realtek_pci_sdmmc *host,
 		break;
 
 	case MMC_TIMING_UHS_DDR50:
-		*ddr_mode = true;
-
 		rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, SD_CFG1,
 				0x0C | SD_ASYNC_FIFO_NOT_RST,
 				SD_DDR_MODE | SD_ASYNC_FIFO_NOT_RST);
@@ -926,7 +926,7 @@ static void sdmmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 	sd_set_bus_width(host, ios->bus_width);
 	sd_set_power_mode(host, ios->power_mode);
-	sd_set_timing(host, ios->timing, &host->ddr_mode);
+	sd_set_timing(host, ios->timing);
 
 	host->vpclk = false;
 	host->double_clk = true;
@@ -1148,9 +1148,35 @@ static int sdmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
 
 	rtsx_pci_start_run(pcr);
 
-	if (!host->ddr_mode)
-		err = sd_tuning_rx(host, MMC_SEND_TUNING_BLOCK);
+	/* Set initial TX phase */
+	switch (mmc->ios.timing) {
+	case MMC_TIMING_UHS_SDR104:
+		err = sd_change_phase(host, SDR104_TX_PHASE(pcr), false);
+		break;
+
+	case MMC_TIMING_UHS_SDR50:
+		err = sd_change_phase(host, SDR50_TX_PHASE(pcr), false);
+		break;
+
+	case MMC_TIMING_UHS_DDR50:
+		err = sd_change_phase(host, DDR50_TX_PHASE(pcr), false);
+		break;
+
+	default:
+		err = 0;
+	}
 
+	if (err)
+		goto out;
+
+	/* Tuning RX phase */
+	if ((mmc->ios.timing == MMC_TIMING_UHS_SDR104) ||
+			(mmc->ios.timing == MMC_TIMING_UHS_SDR50))
+		err = sd_tuning_rx(host, opcode);
+	else if (mmc->ios.timing == MMC_TIMING_UHS_DDR50)
+		err = sd_change_phase(host, DDR50_RX_PHASE(pcr), true);
+
+out:
 	mutex_unlock(&pcr->pcr_mutex);
 
 	return err;