[U-Boot] [PATCH v2] mmc: sdhci-cadence: add HS200 support

[Jaehoon Chung]

Hi Masahiro,

On 01/12/2018 06:10 PM, Masahiro Yamada wrote:
> Add HS200 timing setting and the MMC tuning callback.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> ---
> 
> Changes in v2:
>   - Surround .execute_tuning hook with #ifdef MMC_SUPPORTS_TUNING
> 
>  drivers/mmc/sdhci-cadence.c | 90 ++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 81 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/mmc/sdhci-cadence.c b/drivers/mmc/sdhci-cadence.c
> index 921095b..8960f6f 100644
> --- a/drivers/mmc/sdhci-cadence.c
> +++ b/drivers/mmc/sdhci-cadence.c
> @@ -52,6 +52,13 @@
>  #define SDHCI_CDNS_PHY_DLY_HSMMC	0x0c
>  #define SDHCI_CDNS_PHY_DLY_STROBE	0x0d
>  
> +/*
> + * The tuned val register is 6 bit-wide, but not the whole of the range is
> + * available.  The range 0-42 seems to be available (then 43 wraps around to 0)
> + * but I am not quite sure if it is official.  Use only 0 to 39 for safety.
> + */
> +#define SDHCI_CDNS_MAX_TUNING_LOOP	40
> +
>  struct sdhci_cdns_plat {
>  	struct mmc_config cfg;
>  	struct mmc mmc;
> @@ -135,20 +142,18 @@ static void sdhci_cdns_set_control_reg(struct sdhci_host *host)
>  	 * The mode should be decided by MMC_TIMING_* like Linux, but
>  	 * U-Boot does not support timing.  Use the clock frequency instead.
>  	 */
> -	if (clock <= 26000000)
> +	if (clock <= 26000000) {
>  		mode = SDHCI_CDNS_HRS06_MODE_SD; /* use this for Legacy */
> -	else if (clock <= 52000000) {
> +	} else if (clock <= 52000000) {
>  		if (mmc->ddr_mode)
>  			mode = SDHCI_CDNS_HRS06_MODE_MMC_DDR;
>  		else
>  			mode = SDHCI_CDNS_HRS06_MODE_MMC_SDR;
>  	} else {
> -		/*
> -		 * REVISIT:
> -		 * The IP supports HS200/HS400, revisit once U-Boot support it
> -		 */
> -		printf("unsupported frequency %d\n", clock);
> -		return;
> +		if (mmc->ddr_mode)
> +			mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400;
> +		else
> +			mode = SDHCI_CDNS_HRS06_MODE_MMC_HS200;
>  	}
>  
>  	tmp = readl(plat->hrs_addr + SDHCI_CDNS_HRS06);
> @@ -161,6 +166,69 @@ static const struct sdhci_ops sdhci_cdns_ops = {
>  	.set_control_reg = sdhci_cdns_set_control_reg,
>  };
>  
> +static int sdhci_cdns_set_tune_val(struct sdhci_cdns_plat *plat,
> +				   unsigned int val)
> +{
> +	void __iomem *reg = plat->hrs_addr + SDHCI_CDNS_HRS06;
> +	u32 tmp;
> +
> +	if (WARN_ON(!FIELD_FIT(SDHCI_CDNS_HRS06_TUNE, val)))
> +		return -EINVAL;
> +
> +	tmp = readl(reg);
> +	tmp &= ~SDHCI_CDNS_HRS06_TUNE;
> +	tmp |= FIELD_PREP(SDHCI_CDNS_HRS06_TUNE, val);
> +	tmp |= SDHCI_CDNS_HRS06_TUNE_UP;
> +	writel(tmp, reg);
> +
> +	return readl_poll_timeout(reg, tmp, !(tmp & SDHCI_CDNS_HRS06_TUNE_UP),
> +				  1);
> +}
> +
> +static int __maybe_unused sdhci_cdns_execute_tuning(struct udevice *dev,
> +						    unsigned int opcode)
> +{
> +	struct sdhci_cdns_plat *plat = dev_get_platdata(dev);
> +	struct mmc *mmc = &plat->mmc;
> +	int cur_streak = 0;
> +	int max_streak = 0;
> +	int end_of_streak = 0;
> +	int i;
> +
> +	/*
> +	 * This handler only implements the eMMC tuning that is specific to
> +	 * this controller.  The tuning for SD timing should be handled by the
> +	 * SDHCI core.
> +	 */
> +	if (!IS_MMC(mmc))
> +		return -ENOSYS;

If you're ok, i want to change the return value to ENOTSUPP or other from ENOSYS. How about?

Best Regards,
Jaehoon Chung

> +
> +	if (WARN_ON(opcode != MMC_CMD_SEND_TUNING_BLOCK_HS200))
> +		return -EINVAL;
> +
> +	for (i = 0; i < SDHCI_CDNS_MAX_TUNING_LOOP; i++) {
> +		if (sdhci_cdns_set_tune_val(plat, i) ||
> +		    mmc_send_tuning(mmc, opcode, NULL)) { /* bad */
> +			cur_streak = 0;
> +		} else { /* good */
> +			cur_streak++;
> +			if (cur_streak > max_streak) {
> +				max_streak = cur_streak;
> +				end_of_streak = i;
> +			}
> +		}
> +	}
> +
> +	if (!max_streak) {
> +		dev_err(dev, "no tuning point found\n");
> +		return -EIO;
> +	}
> +
> +	return sdhci_cdns_set_tune_val(plat, end_of_streak - max_streak / 2);
> +}
> +
> +static struct dm_mmc_ops sdhci_cdns_mmc_ops;
> +
>  static int sdhci_cdns_bind(struct udevice *dev)
>  {
>  	struct sdhci_cdns_plat *plat = dev_get_platdata(dev);
> @@ -189,6 +257,10 @@ static int sdhci_cdns_probe(struct udevice *dev)
>  	host->ioaddr = plat->hrs_addr + SDHCI_CDNS_SRS_BASE;
>  	host->ops = &sdhci_cdns_ops;
>  	host->quirks |= SDHCI_QUIRK_WAIT_SEND_CMD;
> +	sdhci_cdns_mmc_ops = sdhci_ops;
> +#ifdef MMC_SUPPORTS_TUNING
> +	sdhci_cdns_mmc_ops.execute_tuning = sdhci_cdns_execute_tuning;
> +#endif
>  
>  	ret = mmc_of_parse(dev, &plat->cfg);
>  	if (ret)
> @@ -223,5 +295,5 @@ U_BOOT_DRIVER(sdhci_cdns) = {
>  	.probe = sdhci_cdns_probe,
>  	.priv_auto_alloc_size = sizeof(struct sdhci_host),
>  	.platdata_auto_alloc_size = sizeof(struct sdhci_cdns_plat),
> -	.ops = &sdhci_ops,
> +	.ops = &sdhci_cdns_mmc_ops,
>  };
>