MMC tuning procedure is required to support SD card UHS1-SDR104 mode and EMMC HS200 mode. SDR104/HS200 DLL Tuning Procedure for AM572x platform is mentioned in Figure 25-51. SDR104/HS200 DLL Tuning Procedure of AM572x Sitara Processors Silicon Revision 2.0, 1.1 TRM (SPRUHZ6I - October 2014–Revised April 2017 [1]). The tuning function sdhci_omap_execute_tuning() will only be called by the MMC/SD core if the corresponding speed modes are supported by the OMAP silicon which is set in the mmc host "caps" field. [1] -> http://www.ti.com/lit/ug/spruhz6i/spruhz6i.pdf Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> --- drivers/mmc/host/sdhci-omap.c | 130 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c index 86b6cc0a5380..36e0626d3de2 100644 --- a/drivers/mmc/host/sdhci-omap.c +++ b/drivers/mmc/host/sdhci-omap.c @@ -37,6 +37,13 @@ #define CON_INIT BIT(1) #define CON_OD BIT(0) +#define SDHCI_OMAP_DLL 0x0134 +#define DLL_SWT BIT(20) +#define DLL_FORCE_SR_C_SHIFT 13 +#define DLL_FORCE_SR_C_MASK (0x7f << DLL_FORCE_SR_C_SHIFT) +#define DLL_FORCE_VALUE BIT(12) +#define DLL_CALIB BIT(1) + #define SDHCI_OMAP_CMD 0x20c #define SDHCI_OMAP_PSTATE 0x0224 @@ -63,12 +70,16 @@ #define SDHCI_OMAP_AC12 0x23c #define AC12_V1V8_SIGEN BIT(19) +#define AC12_SCLK_SEL BIT(23) #define SDHCI_OMAP_CAPA 0x240 #define CAPA_VS33 BIT(24) #define CAPA_VS30 BIT(25) #define CAPA_VS18 BIT(26) +#define SDHCI_OMAP_CAPA2 0x0244 +#define CAPA2_TSDR50 BIT(13) + #define SDHCI_OMAP_TIMEOUT 1 /* 1 msec */ #define SYSCTL_CLKD_MAX 0x3FF @@ -77,6 +88,8 @@ #define IOV_3V0 3000000 /* 300000 uV */ #define IOV_3V3 3300000 /* 330000 uV */ +#define MAX_PHASE_DELAY 0x7C + struct sdhci_omap_data { u32 offset; }; @@ -198,6 +211,120 @@ static void sdhci_omap_conf_bus_power(struct sdhci_omap_host *omap_host, } } +static inline void sdhci_omap_set_dll(struct sdhci_omap_host *omap_host, + int count) +{ + int i; + u32 reg; + + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL); + reg |= DLL_FORCE_VALUE; + reg &= ~DLL_FORCE_SR_C_MASK; + reg |= (count << DLL_FORCE_SR_C_SHIFT); + sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg); + + reg |= DLL_CALIB; + sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg); + for (i = 0; i < 1000; i++) { + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL); + if (reg & DLL_CALIB) + break; + } + reg &= ~DLL_CALIB; + sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg); +} + +static void sdhci_omap_disable_tuning(struct sdhci_omap_host *omap_host) +{ + u32 reg; + + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_AC12); + reg &= ~AC12_SCLK_SEL; + sdhci_omap_writel(omap_host, SDHCI_OMAP_AC12, reg); + + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL); + reg &= ~(DLL_FORCE_VALUE | DLL_SWT); + sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg); +} + +static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) +{ + struct sdhci_host *host = mmc_priv(mmc); + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host); + struct device *dev = omap_host->dev; + struct mmc_ios *ios = &mmc->ios; + u32 start_window = 0, max_window = 0; + u8 cur_match, prev_match = 0; + u32 length = 0, max_len = 0; + u32 phase_delay = 0; + int ret = 0; + u32 reg; + + pltfm_host = sdhci_priv(host); + omap_host = sdhci_pltfm_priv(pltfm_host); + dev = omap_host->dev; + + /* clock tuning is not needed for upto 52MHz */ + if (ios->clock <= 52000000) + return 0; + + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_CAPA2); + if (ios->timing == MMC_TIMING_UHS_SDR50 && !(reg & CAPA2_TSDR50)) + return 0; + + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL); + reg |= DLL_SWT; + sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg); + + while (phase_delay <= MAX_PHASE_DELAY) { + sdhci_omap_set_dll(omap_host, phase_delay); + + cur_match = !mmc_send_tuning(mmc, opcode, NULL); + if (cur_match) { + if (prev_match) { + length++; + } else { + start_window = phase_delay; + length = 1; + } + } + + if (length > max_len) { + max_window = start_window; + max_len = length; + } + + prev_match = cur_match; + phase_delay += 4; + } + + if (!max_len) { + dev_err(dev, "Unable to find match\n"); + ret = -EIO; + goto tuning_error; + } + + reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_AC12); + if (!(reg & AC12_SCLK_SEL)) { + ret = -EIO; + goto tuning_error; + } + + phase_delay = max_window + 4 * (max_len >> 1); + sdhci_omap_set_dll(omap_host, phase_delay); + + goto ret; + +tuning_error: + dev_err(dev, "Tuning failed\n"); + sdhci_omap_disable_tuning(omap_host); + +ret: + sdhci_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA); + return ret; +} + static int sdhci_omap_card_busy(struct mmc_host *mmc) { u32 reg, ac12; @@ -299,6 +426,8 @@ static int sdhci_omap_start_signal_voltage_switch(struct mmc_host *mmc, static void sdhci_omap_set_power_mode(struct sdhci_omap_host *omap_host, u8 power_mode) { + if (omap_host->bus_mode == MMC_POWER_OFF) + sdhci_omap_disable_tuning(omap_host); omap_host->power_mode = power_mode; } @@ -635,6 +764,7 @@ static int sdhci_omap_probe(struct platform_device *pdev) sdhci_omap_start_signal_voltage_switch; host->mmc_host_ops.set_ios = sdhci_omap_set_ios; host->mmc_host_ops.card_busy = sdhci_omap_card_busy; + host->mmc_host_ops.execute_tuning = sdhci_omap_execute_tuning; sdhci_read_caps(host); host->caps |= SDHCI_CAN_DO_ADMA2; -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
