linux-kernel - Re: [PATCH] mmc: sdhci-of-arasan: Add support for dynamic configuration

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Message-ID: <54973f0b-33ab-6cbb-82ce-be769fe82bd9@intel.com>
Date:   Wed, 2 Nov 2022 11:37:19 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Sai Krishna Potthuri <sai.krishna.potthuri@....com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Michal Simek <michal.simek@...inx.com>,
        Philipp Zabel <p.zabel@...gutronix.de>
Cc:     linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, saikrishna12468@...il.com,
        git@....com
Subject: Re: [PATCH] mmc: sdhci-of-arasan: Add support for dynamic
 configuration

On 19/10/22 08:48, Sai Krishna Potthuri wrote:
> Add dynamic configuration support for Xilinx ZynqMP which takes care of
> configuring the SD secure space configuration registers using EEMI APIs,
> performing SD reset assert and deassert.
> High level sequence:
> - Check for the PM dynamic configuration support, if no error proceed with
> SD dynamic configurations(next steps) otherwise skip the dynamic
> configuration.
> - Put the SD Controller in reset.
> - Configure SD Fixed configurations.
> - Configure the SD Slot Type.
> - Configure the BASE_CLOCK.
> - Configure the 8-bit support.
> - Bring the SD Controller out of reset.
> - Wait for 1msec delay.
> 
> Signed-off-by: Sai Krishna Potthuri <sai.krishna.potthuri@....com>

Can we get an Ack from xilinx folks?

> ---
>  drivers/mmc/host/sdhci-of-arasan.c | 69 ++++++++++++++++++++++++++++++
>  1 file changed, 69 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index 3997cad1f793..f051f3802aff 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -21,6 +21,7 @@
>  #include <linux/of_device.h>
>  #include <linux/phy/phy.h>
>  #include <linux/regmap.h>
> +#include <linux/reset.h>
>  #include <linux/of.h>
>  #include <linux/firmware/xlnx-zynqmp.h>
>  
> @@ -1521,6 +1522,65 @@ static int sdhci_arasan_register_sdclk(struct sdhci_arasan_data *sdhci_arasan,
>  	return 0;
>  }
>  
> +static int sdhci_zynqmp_set_dynamic_config(struct device *dev,
> +					   struct sdhci_arasan_data *sdhci_arasan)
> +{
> +	struct sdhci_host *host = sdhci_arasan->host;
> +	struct clk_hw *hw = &sdhci_arasan->clk_data.sdcardclk_hw;
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	const char *clk_name = clk_hw_get_name(hw);
> +	u32 mhz, node_id = !strcmp(clk_name, "clk_out_sd0") ? NODE_SD_0 : NODE_SD_1;
> +	struct reset_control *rstc;
> +	int ret;
> +
> +	/* Obtain SDHC reset control */
> +	rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(rstc)) {
> +		dev_err(dev, "Cannot get SDHC reset.\n");
> +		return PTR_ERR(rstc);
> +	}
> +
> +	ret = reset_control_assert(rstc);
> +	if (ret)
> +		return ret;
> +
> +	ret = zynqmp_pm_set_sd_config(node_id, SD_CONFIG_FIXED, 0);
> +	if (ret)
> +		return ret;
> +
> +	ret = zynqmp_pm_set_sd_config(node_id, SD_CONFIG_EMMC_SEL,
> +				      !!(host->mmc->caps & MMC_CAP_NONREMOVABLE));
> +	if (ret)
> +		return ret;
> +
> +	mhz = DIV_ROUND_CLOSEST_ULL(clk_get_rate(pltfm_host->clk), 1000000);
> +	if (mhz > 100 && mhz <= 200)
> +		mhz = 200;
> +	else if (mhz > 50 && mhz <= 100)
> +		mhz = 100;
> +	else if (mhz > 25 && mhz <= 50)
> +		mhz = 50;
> +	else
> +		mhz = 25;
> +
> +	ret = zynqmp_pm_set_sd_config(node_id, SD_CONFIG_BASECLK, mhz);
> +	if (ret)
> +		return ret;
> +
> +	ret = zynqmp_pm_set_sd_config(node_id, SD_CONFIG_8BIT,
> +				      !!(host->mmc->caps & MMC_CAP_8_BIT_DATA));
> +	if (ret)
> +		return ret;
> +
> +	ret = reset_control_deassert(rstc);
> +	if (ret)
> +		return ret;
> +
> +	usleep_range(1000, 1500);
> +
> +	return 0;
> +}
> +
>  static int sdhci_arasan_add_host(struct sdhci_arasan_data *sdhci_arasan)
>  {
>  	struct sdhci_host *host = sdhci_arasan->host;
> @@ -1685,6 +1745,15 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>  		goto unreg_clk;
>  	}
>  
> +	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a")) {
> +		ret = zynqmp_pm_is_function_supported(PM_IOCTL, IOCTL_SET_SD_CONFIG);
> +		if (!ret) {
> +			ret = sdhci_zynqmp_set_dynamic_config(dev, sdhci_arasan);
> +			if (ret)
> +				goto unreg_clk;
> +		}
> +	}
> +
>  	sdhci_arasan->phy = ERR_PTR(-ENODEV);
>  	if (of_device_is_compatible(np, "arasan,sdhci-5.1")) {
>  		sdhci_arasan->phy = devm_phy_get(dev, "phy_arasan");