Date:   Tue, 28 Mar 2023 00:01:59 +0800
From:   Shengyu Qu <wiagn233@...look.com>
To:     William Qiu <william.qiu@...rfivetech.com>,
        linux-riscv@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-mmc@...r.kernel.org
Cc:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Jaehoon Chung <jh80.chung@...sung.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/4] mmc: starfive: Add sdio/emmc driver support

Hello William,

I'm digging into downstream mmc driver these days and found a problem

that current version mainline driver doesn't has a voltage switch 
function for

it. Downstream older version has one but was deleted in this commit [1].

It was deleted since vf2's SD slot doesn't have 1.8V input but commiter 
forgot

that vf2's eMMC slot has a proper 1.8V input.

So could you add voltage switch function for mainline? I've met a eMMC speed

problem possibly due to it.

Best regards,

Shengyu

[1] 
https://github.com/starfive-tech/linux/commit/8037d59091d276e74be38e5fafaaebe36eaa77e1

在 2023/2/15 19:32, William Qiu 写道:
> Add sdio/emmc driver support for StarFive JH7110 soc.
>
> Tested-by: Conor Dooley <conor.dooley@...rochip.com>
> Signed-off-by: William Qiu <william.qiu@...rfivetech.com>
> ---
>   MAINTAINERS                        |   6 +
>   drivers/mmc/host/Kconfig           |  10 ++
>   drivers/mmc/host/Makefile          |   1 +
>   drivers/mmc/host/dw_mmc-starfive.c | 186 +++++++++++++++++++++++++++++
>   4 files changed, 203 insertions(+)
>   create mode 100644 drivers/mmc/host/dw_mmc-starfive.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 85e8f83161d7..644ac9479a6e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19640,6 +19640,12 @@ F:	Documentation/devicetree/bindings/clock/starfive,jh71*.yaml
>   F:	drivers/clk/starfive/clk-starfive-jh71*
>   F:	include/dt-bindings/clock/starfive?jh71*.h
>   
> +STARFIVE JH7110 MMC/SD/SDIO DRIVER
> +M:	William Qiu <william.qiu@...rfivetech.com>
> +S:	Supported
> +F:	Documentation/devicetree/bindings/mmc/starfive*
> +F:	drivers/mmc/host/dw_mmc-starfive.c
> +
>   STARFIVE JH71X0 PINCTRL DRIVERS
>   M:	Emil Renner Berthing <kernel@...il.dk>
>   M:	Jianlong Huang <jianlong.huang@...rfivetech.com>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index fb1062a6394c..b87262503403 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -871,6 +871,16 @@ config MMC_DW_ROCKCHIP
>   	  Synopsys DesignWare Memory Card Interface driver. Select this option
>   	  for platforms based on RK3066, RK3188 and RK3288 SoC's.
>   
> +config MMC_DW_STARFIVE
> +	tristate "StarFive specific extensions for Synopsys DW Memory Card Interface"
> +	depends on SOC_STARFIVE
> +	depends on MMC_DW
> +	select MMC_DW_PLTFM
> +	help
> +	  This selects support for StarFive JH7110 SoC specific extensions to the
> +	  Synopsys DesignWare Memory Card Interface driver. Select this option
> +	  for platforms based on StarFive JH7110 SoC.
> +
>   config MMC_SH_MMCIF
>   	tristate "SuperH Internal MMCIF support"
>   	depends on SUPERH || ARCH_RENESAS || COMPILE_TEST
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index 4e4ceb32c4b4..32c0e5564b9a 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_MMC_DW_HI3798CV200) += dw_mmc-hi3798cv200.o
>   obj-$(CONFIG_MMC_DW_K3)		+= dw_mmc-k3.o
>   obj-$(CONFIG_MMC_DW_PCI)	+= dw_mmc-pci.o
>   obj-$(CONFIG_MMC_DW_ROCKCHIP)	+= dw_mmc-rockchip.o
> +obj-$(CONFIG_MMC_DW_STARFIVE)	+= dw_mmc-starfive.o
>   obj-$(CONFIG_MMC_SH_MMCIF)	+= sh_mmcif.o
>   obj-$(CONFIG_MMC_JZ4740)	+= jz4740_mmc.o
>   obj-$(CONFIG_MMC_VUB300)	+= vub300.o
> diff --git a/drivers/mmc/host/dw_mmc-starfive.c b/drivers/mmc/host/dw_mmc-starfive.c
> new file mode 100644
> index 000000000000..40f5969b07a6
> --- /dev/null
> +++ b/drivers/mmc/host/dw_mmc-starfive.c
> @@ -0,0 +1,186 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * StarFive Designware Mobile Storage Host Controller Driver
> + *
> + * Copyright (c) 2022 StarFive Technology Co., Ltd.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mmc/host.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include "dw_mmc.h"
> +#include "dw_mmc-pltfm.h"
> +
> +#define ALL_INT_CLR		0x1ffff
> +#define MAX_DELAY_CHAIN		32
> +
> +struct starfive_priv {
> +	struct device *dev;
> +	struct regmap *reg_syscon;
> +	u32 syscon_offset;
> +	u32 syscon_shift;
> +	u32 syscon_mask;
> +};
> +
> +static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> +{
> +	int ret;
> +	unsigned int clock;
> +
> +	if (ios->timing == MMC_TIMING_MMC_DDR52 || ios->timing == MMC_TIMING_UHS_DDR50) {
> +		clock = (ios->clock > 50000000 && ios->clock <= 52000000) ? 100000000 : ios->clock;
> +		ret = clk_set_rate(host->ciu_clk, clock);
> +		if (ret)
> +			dev_dbg(host->dev, "Use an external frequency divider %uHz\n", ios->clock);
> +		host->bus_hz = clk_get_rate(host->ciu_clk);
> +	} else {
> +		dev_dbg(host->dev, "Using the internal divider\n");
> +	}
> +}
> +
> +static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
> +					     u32 opcode)
> +{
> +	static const int grade  = MAX_DELAY_CHAIN;
> +	struct dw_mci *host = slot->host;
> +	struct starfive_priv *priv = host->priv;
> +	int rise_point = -1, fall_point = -1;
> +	int err, prev_err;
> +	int i;
> +	bool found = 0;
> +	u32 regval;
> +
> +	/*
> +	 * Use grade as the max delay chain, and use the rise_point and
> +	 * fall_point to ensure the best sampling point of a data input
> +	 * signals.
> +	 */
> +	for (i = 0; i < grade; i++) {
> +		regval = i << priv->syscon_shift;
> +		err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
> +						priv->syscon_mask, regval);
> +		if (err)
> +			return err;
> +		mci_writel(host, RINTSTS, ALL_INT_CLR);
> +
> +		err = mmc_send_tuning(slot->mmc, opcode, NULL);
> +		if (!err)
> +			found = 1;
> +
> +		if (i > 0) {
> +			if (err && !prev_err)
> +				fall_point = i - 1;
> +			if (!err && prev_err)
> +				rise_point = i;
> +		}
> +
> +		if (rise_point != -1 && fall_point != -1)
> +			goto tuning_out;
> +
> +		prev_err = err;
> +		err = 0;
> +	}
> +
> +tuning_out:
> +	if (found) {
> +		if (rise_point == -1)
> +			rise_point = 0;
> +		if (fall_point == -1)
> +			fall_point = grade - 1;
> +		if (fall_point < rise_point) {
> +			if ((rise_point + fall_point) >
> +			    (grade - 1))
> +				i = fall_point / 2;
> +			else
> +				i = (rise_point + grade - 1) / 2;
> +		} else {
> +			i = (rise_point + fall_point) / 2;
> +		}
> +
> +		regval = i << priv->syscon_shift;
> +		err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
> +						priv->syscon_mask, regval);
> +		if (err)
> +			return err;
> +		mci_writel(host, RINTSTS, ALL_INT_CLR);
> +
> +		dev_info(host->dev, "Found valid delay chain! use it [delay=%d]\n", i);
> +	} else {
> +		dev_err(host->dev, "No valid delay chain! use default\n");
> +		err = -EINVAL;
> +	}
> +
> +	mci_writel(host, RINTSTS, ALL_INT_CLR);
> +	return err;
> +}
> +
> +static int dw_mci_starfive_parse_dt(struct dw_mci *host)
> +{
> +	struct of_phandle_args args;
> +	struct starfive_priv *priv;
> +	int ret;
> +
> +	priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	ret = of_parse_phandle_with_fixed_args(host->dev->of_node,
> +						"starfive,sysreg", 3, 0, &args);
> +	if (ret) {
> +		dev_err(host->dev, "Failed to parse starfive,sysreg\n");
> +		return -EINVAL;
> +	}
> +
> +	priv->reg_syscon = syscon_node_to_regmap(args.np);
> +	of_node_put(args.np);
> +	if (IS_ERR(priv->reg_syscon))
> +		return PTR_ERR(priv->reg_syscon);
> +
> +	priv->syscon_offset = args.args[0];
> +	priv->syscon_shift  = args.args[1];
> +	priv->syscon_mask   = args.args[2];
> +
> +	host->priv = priv;
> +
> +	return 0;
> +}
> +
> +static const struct dw_mci_drv_data starfive_data = {
> +	.common_caps		= MMC_CAP_CMD23,
> +	.set_ios		= dw_mci_starfive_set_ios,
> +	.parse_dt		= dw_mci_starfive_parse_dt,
> +	.execute_tuning		= dw_mci_starfive_execute_tuning,
> +};
> +
> +static const struct of_device_id dw_mci_starfive_match[] = {
> +	{ .compatible = "starfive,jh7110-mmc",
> +		.data = &starfive_data },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, dw_mci_starfive_match);
> +
> +static int dw_mci_starfive_probe(struct platform_device *pdev)
> +{
> +	return dw_mci_pltfm_register(pdev, &starfive_data);
> +}
> +
> +static struct platform_driver dw_mci_starfive_driver = {
> +	.probe = dw_mci_starfive_probe,
> +	.remove = dw_mci_pltfm_remove,
> +	.driver = {
> +		.name = "dwmmc_starfive",
> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> +		.of_match_table = dw_mci_starfive_match,
> +	},
> +};
> +module_platform_driver(dw_mci_starfive_driver);
> +
> +MODULE_DESCRIPTION("StarFive JH7110 Specific DW-MSHC Driver Extension");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:dwmmc_starfive");

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