mmc: sh_mobile_sdhi: Add tuning support
authorSimon Horman <horms+renesas@verge.net.au>
Thu, 3 Nov 2016 14:16:04 +0000 (15:16 +0100)
committerUlf Hansson <ulf.hansson@linaro.org>
Tue, 29 Nov 2016 08:00:58 +0000 (09:00 +0100)
Add tuning support for use with SDR104 mode
This includes adding support for the sampling clock controller (SCC).

Based on work by Ai Kyuse.

Cc: Ai Kyuse <ai.kyuse.uw@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
drivers/mmc/host/sh_mobile_sdhi.c

index bda5e6745701fe00d916881eb404faeccf79993f..d46c2d00c18244b1c082497a42b6a97ca019ae60 100644 (file)
 
 #define host_to_priv(host) container_of((host)->pdata, struct sh_mobile_sdhi, mmc_data)
 
+struct sh_mobile_sdhi_scc {
+       unsigned long clk_rate; /* clock rate for SDR104 */
+       u32 tap;                /* sampling clock position for SDR104 */
+};
+
 struct sh_mobile_sdhi_of_data {
        unsigned long tmio_flags;
        u32           tmio_ocr_mask;
@@ -55,6 +60,9 @@ struct sh_mobile_sdhi_of_data {
        enum dma_slave_buswidth dma_buswidth;
        dma_addr_t dma_rx_offset;
        unsigned bus_shift;
+       int scc_offset;
+       struct sh_mobile_sdhi_scc *taps;
+       int taps_num;
 };
 
 static const struct sh_mobile_sdhi_of_data of_default_cfg = {
@@ -73,12 +81,35 @@ static const struct sh_mobile_sdhi_of_data of_rcar_gen1_compatible = {
        .capabilities   = MMC_CAP_SD_HIGHSPEED | MMC_CAP_SDIO_IRQ,
 };
 
+/* Definitions for sampling clocks */
+static struct sh_mobile_sdhi_scc rcar_gen2_scc_taps[] = {
+       {
+               .clk_rate = 156000000,
+               .tap = 0x00000703,
+       },
+       {
+               .clk_rate = 0,
+               .tap = 0x00000300,
+       },
+};
+
 static const struct sh_mobile_sdhi_of_data of_rcar_gen2_compatible = {
        .tmio_flags     = TMIO_MMC_HAS_IDLE_WAIT | TMIO_MMC_WRPROTECT_DISABLE |
                          TMIO_MMC_CLK_ACTUAL | TMIO_MMC_MIN_RCAR2,
        .capabilities   = MMC_CAP_SD_HIGHSPEED | MMC_CAP_SDIO_IRQ,
        .dma_buswidth   = DMA_SLAVE_BUSWIDTH_4_BYTES,
        .dma_rx_offset  = 0x2000,
+       .scc_offset     = 0x0300,
+       .taps           = rcar_gen2_scc_taps,
+       .taps_num       = ARRAY_SIZE(rcar_gen2_scc_taps),
+};
+
+/* Definitions for sampling clocks */
+static struct sh_mobile_sdhi_scc rcar_gen3_scc_taps[] = {
+       {
+               .clk_rate = 0,
+               .tap = 0x00000300,
+       },
 };
 
 static const struct sh_mobile_sdhi_of_data of_rcar_gen3_compatible = {
@@ -86,6 +117,9 @@ static const struct sh_mobile_sdhi_of_data of_rcar_gen3_compatible = {
                          TMIO_MMC_CLK_ACTUAL | TMIO_MMC_MIN_RCAR2,
        .capabilities   = MMC_CAP_SD_HIGHSPEED | MMC_CAP_SDIO_IRQ,
        .bus_shift      = 2,
+       .scc_offset     = 0x1000,
+       .taps           = rcar_gen3_scc_taps,
+       .taps_num       = ARRAY_SIZE(rcar_gen3_scc_taps),
 };
 
 static const struct of_device_id sh_mobile_sdhi_of_match[] = {
@@ -113,6 +147,7 @@ struct sh_mobile_sdhi {
        struct tmio_mmc_dma dma_priv;
        struct pinctrl *pinctrl;
        struct pinctrl_state *pins_default, *pins_uhs;
+       void __iomem *scc_ctl;
 };
 
 static void sh_mobile_sdhi_sdbuf_width(struct tmio_mmc_host *host, int width)
@@ -263,6 +298,201 @@ static int sh_mobile_sdhi_start_signal_voltage_switch(struct mmc_host *mmc,
        return pinctrl_select_state(priv->pinctrl, pin_state);
 }
 
+/* SCC registers */
+#define SH_MOBILE_SDHI_SCC_DTCNTL      0x000
+#define SH_MOBILE_SDHI_SCC_TAPSET      0x002
+#define SH_MOBILE_SDHI_SCC_DT2FF       0x004
+#define SH_MOBILE_SDHI_SCC_CKSEL       0x006
+#define SH_MOBILE_SDHI_SCC_RVSCNTL     0x008
+#define SH_MOBILE_SDHI_SCC_RVSREQ      0x00A
+
+/* Definitions for values the SH_MOBILE_SDHI_SCC_DTCNTL register */
+#define SH_MOBILE_SDHI_SCC_DTCNTL_TAPEN                BIT(0)
+#define SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT 16
+#define SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_MASK  0xff
+
+/* Definitions for values the SH_MOBILE_SDHI_SCC_CKSEL register */
+#define SH_MOBILE_SDHI_SCC_CKSEL_DTSEL         BIT(0)
+/* Definitions for values the SH_MOBILE_SDHI_SCC_RVSCNTL register */
+#define SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN       BIT(0)
+/* Definitions for values the SH_MOBILE_SDHI_SCC_RVSREQ register */
+#define SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR       BIT(2)
+
+static inline u32 sd_scc_read32(struct tmio_mmc_host *host,
+                               struct sh_mobile_sdhi *priv, int addr)
+{
+       return readl(priv->scc_ctl + (addr << host->bus_shift));
+}
+
+static inline void sd_scc_write32(struct tmio_mmc_host *host,
+                                 struct sh_mobile_sdhi *priv,
+                                 int addr, u32 val)
+{
+       writel(val, priv->scc_ctl + (addr << host->bus_shift));
+}
+
+static unsigned int sh_mobile_sdhi_init_tuning(struct tmio_mmc_host *host)
+{
+       struct sh_mobile_sdhi *priv;
+
+       if (!(host->mmc->caps & MMC_CAP_UHS_SDR104))
+               return 0;
+
+       priv = host_to_priv(host);
+
+       /* set sampling clock selection range */
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
+                      0x8 << SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT);
+
+       /* Initialize SCC */
+       sd_ctrl_write32_as_16_and_16(host, CTL_STATUS, 0x0);
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
+                      SH_MOBILE_SDHI_SCC_DTCNTL_TAPEN |
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL));
+
+       sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
+                       sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL,
+                      SH_MOBILE_SDHI_SCC_CKSEL_DTSEL |
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));
+
+       sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
+                       sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
+                      ~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DT2FF, host->scc_tappos);
+
+       /* Read TAPNUM */
+       return (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL) >>
+               SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT) &
+               SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_MASK;
+}
+
+static void sh_mobile_sdhi_prepare_tuning(struct tmio_mmc_host *host,
+                                        unsigned long tap)
+{
+       struct sh_mobile_sdhi *priv = host_to_priv(host);
+
+       /* Set sampling clock position */
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, tap);
+}
+
+#define SH_MOBILE_SDHI_MAX_TAP 3
+
+static int sh_mobile_sdhi_select_tuning(struct tmio_mmc_host *host)
+{
+       struct sh_mobile_sdhi *priv = host_to_priv(host);
+       unsigned long tap_cnt;  /* counter of tuning success */
+       unsigned long tap_set;  /* tap position */
+       unsigned long tap_start;/* start position of tuning success */
+       unsigned long tap_end;  /* end position of tuning success */
+       unsigned long ntap;     /* temporary counter of tuning success */
+       unsigned long i;
+
+       /* Clear SCC_RVSREQ */
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
+
+       /*
+        * Find the longest consecutive run of successful probes.  If that
+        * is more than SH_MOBILE_SDHI_MAX_TAP probes long then use the
+        * center index as the tap.
+        */
+       tap_cnt = 0;
+       ntap = 0;
+       tap_start = 0;
+       tap_end = 0;
+       for (i = 0; i < host->tap_num * 2; i++) {
+               if (test_bit(i, host->taps))
+                       ntap++;
+               else {
+                       if (ntap > tap_cnt) {
+                               tap_start = i - ntap;
+                               tap_end = i - 1;
+                               tap_cnt = ntap;
+                       }
+                       ntap = 0;
+               }
+       }
+
+       if (ntap > tap_cnt) {
+               tap_start = i - ntap;
+               tap_end = i - 1;
+               tap_cnt = ntap;
+       }
+
+       if (tap_cnt >= SH_MOBILE_SDHI_MAX_TAP)
+               tap_set = (tap_start + tap_end) / 2 % host->tap_num;
+       else
+               return -EIO;
+
+       /* Set SCC */
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, tap_set);
+
+       /* Enable auto re-tuning */
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
+                      SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN |
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
+
+       return 0;
+}
+
+
+static bool sh_mobile_sdhi_check_scc_error(struct tmio_mmc_host *host)
+{
+       struct sh_mobile_sdhi *priv;
+
+       if (!(host->mmc->caps & MMC_CAP_UHS_SDR104))
+               return 0;
+
+       priv = host_to_priv(host);
+
+       /* Check SCC error */
+       if (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL) &
+           SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &&
+           sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ) &
+           SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR) {
+               /* Clear SCC error */
+               sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
+               return true;
+       }
+
+       return false;
+}
+
+static void sh_mobile_sdhi_hw_reset(struct tmio_mmc_host *host)
+{
+       struct sh_mobile_sdhi *priv;
+
+       if (!(host->mmc->caps & MMC_CAP_UHS_SDR104))
+               return;
+
+       priv = host_to_priv(host);
+
+       /* Reset SCC */
+       sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
+                       sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL,
+                      ~SH_MOBILE_SDHI_SCC_CKSEL_DTSEL &
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));
+
+       sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
+                       sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
+                      ~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
+
+       sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
+                      ~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
+                      sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
+}
+
 static int sh_mobile_sdhi_wait_idle(struct tmio_mmc_host *host)
 {
        int timeout = 1000;
@@ -333,7 +563,7 @@ static int sh_mobile_sdhi_probe(struct platform_device *pdev)
        struct tmio_mmc_data *mmd = pdev->dev.platform_data;
        struct tmio_mmc_host *host;
        struct resource *res;
-       int irq, ret, i = 0;
+       int irq, ret, i;
        struct tmio_mmc_dma *dma_priv;
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -393,6 +623,11 @@ static int sh_mobile_sdhi_probe(struct platform_device *pdev)
                host->card_busy = sh_mobile_sdhi_card_busy;
                host->start_signal_voltage_switch =
                        sh_mobile_sdhi_start_signal_voltage_switch;
+               host->init_tuning       = sh_mobile_sdhi_init_tuning;
+               host->prepare_tuning    = sh_mobile_sdhi_prepare_tuning;
+               host->select_tuning     = sh_mobile_sdhi_select_tuning;
+               host->check_scc_error   = sh_mobile_sdhi_check_scc_error;
+               host->hw_reset          = sh_mobile_sdhi_hw_reset;
        }
 
        /* Orginally registers were 16 bit apart, could be 32 or 64 nowadays */
@@ -433,6 +668,34 @@ static int sh_mobile_sdhi_probe(struct platform_device *pdev)
        if (ret < 0)
                goto efree;
 
+       if (host->mmc->caps & MMC_CAP_UHS_SDR104) {
+               host->mmc->caps |= MMC_CAP_HW_RESET;
+
+               if (of_id && of_id->data) {
+                       const struct sh_mobile_sdhi_of_data *of_data;
+                       const struct sh_mobile_sdhi_scc *taps;
+                       bool hit = false;
+
+                       of_data = of_id->data;
+                       taps = of_data->taps;
+
+                       for (i = 0; i < of_data->taps_num; i++) {
+                               if (taps[i].clk_rate == 0 ||
+                                   taps[i].clk_rate == host->mmc->f_max) {
+                                       host->scc_tappos = taps->tap;
+                                       hit = true;
+                                       break;
+                               }
+                       }
+
+                       if (!hit)
+                               dev_warn(&host->pdev->dev, "Unknown clock rate for SDR104\n");
+
+                       priv->scc_ctl = host->ctl + of_data->scc_offset;
+               }
+       }
+
+       i = 0;
        while (1) {
                irq = platform_get_irq(pdev, i);
                if (irq < 0)