Date:   Thu, 25 Nov 2021 14:21:06 -0800
From:   Colin Foster <colin.foster@in-advantage.com>
To:     linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc:     Vladimir Oltean <vladimir.oltean@nxp.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        UNGLinuxDriver@microchip.com, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>
Subject: Re: [PATCH v2 net-next 1/3] net: mdio: mscc-miim: convert to a
 regmap implementation
Message-ID: <20211125222106.GA3750811@euler>
References: <20211125201301.3748513-1-colin.foster@in-advantage.com>
 <20211125201301.3748513-2-colin.foster@in-advantage.com>
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On Thu, Nov 25, 2021 at 12:12:59PM -0800, Colin Foster wrote:
> Utilize regmap instead of __iomem to perform indirect mdio access. This
> will allow for custom regmaps to be used by way of the mscc_miim_setup
> function.
> 
> Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
> ---
>  drivers/net/mdio/mdio-mscc-miim.c | 161 ++++++++++++++++++++++--------
>  1 file changed, 119 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/net/mdio/mdio-mscc-miim.c b/drivers/net/mdio/mdio-mscc-miim.c
> index 17f98f609ec8..5a9c0b311bdb 100644
> --- a/drivers/net/mdio/mdio-mscc-miim.c
> +++ b/drivers/net/mdio/mdio-mscc-miim.c
> @@ -14,6 +14,7 @@
>  #include <linux/of_mdio.h>
>  #include <linux/phy.h>
>  #include <linux/platform_device.h>
> +#include <linux/regmap.h>
>  
>  #define MSCC_MIIM_REG_STATUS		0x0
>  #define		MSCC_MIIM_STATUS_STAT_PENDING	BIT(2)
> @@ -35,37 +36,49 @@
>  #define MSCC_PHY_REG_PHY_STATUS	0x4
>  
>  struct mscc_miim_dev {
> -	void __iomem *regs;
> -	void __iomem *phy_regs;
> +	struct regmap *regs;
> +	struct regmap *phy_regs;
>  };
>  
>  /* When high resolution timers aren't built-in: we can't use usleep_range() as
>   * we would sleep way too long. Use udelay() instead.
>   */
> -#define mscc_readl_poll_timeout(addr, val, cond, delay_us, timeout_us)	\
> -({									\
> -	if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS))			\
> -		readl_poll_timeout_atomic(addr, val, cond, delay_us,	\
> -					  timeout_us);			\
> -	readl_poll_timeout(addr, val, cond, delay_us, timeout_us);	\
> +#define mscc_readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us)\
> +({									  \
> +	if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS))			  \
> +		readx_poll_timeout_atomic(op, addr, val, cond, delay_us,  \
> +					  timeout_us);			  \
> +	readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us);	  \
>  })
>  
> -static int mscc_miim_wait_ready(struct mii_bus *bus)
> +static int mscc_miim_status(struct mii_bus *bus)
>  {
>  	struct mscc_miim_dev *miim = bus->priv;
> +	int val, ret;
> +
> +	ret = regmap_read(miim->regs, MSCC_MIIM_REG_STATUS, &val);
> +	if (ret < 0) {
> +		WARN_ONCE(1, "mscc miim status read error %d\n", ret);
> +		return ret;
> +	}
> +
> +	return val;
> +}
> +
> +static int mscc_miim_wait_ready(struct mii_bus *bus)
> +{
>  	u32 val;
>  
> -	return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
> +	return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
>  				       !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
>  				       10000);
>  }
>  
>  static int mscc_miim_wait_pending(struct mii_bus *bus)
>  {
> -	struct mscc_miim_dev *miim = bus->priv;
>  	u32 val;
>  
> -	return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
> +	return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
>  				       !(val & MSCC_MIIM_STATUS_STAT_PENDING),
>  				       50, 10000);
>  }
> @@ -80,15 +93,27 @@ static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
>  	if (ret)
>  		goto out;
>  
> -	writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
> -	       (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) | MSCC_MIIM_CMD_OPR_READ,
> -	       miim->regs + MSCC_MIIM_REG_CMD);
> +	ret = regmap_write(miim->regs, MSCC_MIIM_REG_CMD, MSCC_MIIM_CMD_VLD |
> +			   (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
> +			   (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
> +			   MSCC_MIIM_CMD_OPR_READ);
> +
> +	if (ret < 0) {
> +		WARN_ONCE(1, "mscc miim write cmd reg error %d\n", ret);
> +		goto out;
> +	}
>  
>  	ret = mscc_miim_wait_ready(bus);
>  	if (ret)
>  		goto out;
>  
> -	val = readl(miim->regs + MSCC_MIIM_REG_DATA);
> +	ret = regmap_read(miim->regs, MSCC_MIIM_REG_DATA, &val);
> +
> +	if (ret < 0) {
> +		WARN_ONCE(1, "mscc miim read data reg error %d\n", ret);
> +		goto out;
> +	}
> +
>  	if (val & MSCC_MIIM_DATA_ERROR) {
>  		ret = -EIO;
>  		goto out;
> @@ -109,12 +134,14 @@ static int mscc_miim_write(struct mii_bus *bus, int mii_id,
>  	if (ret < 0)
>  		goto out;
>  
> -	writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
> -	       (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
> -	       (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
> -	       MSCC_MIIM_CMD_OPR_WRITE,
> -	       miim->regs + MSCC_MIIM_REG_CMD);
> +	ret = regmap_write(miim->regs, MSCC_MIIM_REG_CMD, MSCC_MIIM_CMD_VLD |
> +			   (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
> +			   (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
> +			   (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
> +			   MSCC_MIIM_CMD_OPR_WRITE);
>  
> +	if (ret < 0)
> +		WARN_ONCE(1, "mscc miim write error %d\n", ret);
>  out:
>  	return ret;
>  }
> @@ -122,24 +149,40 @@ static int mscc_miim_write(struct mii_bus *bus, int mii_id,
>  static int mscc_miim_reset(struct mii_bus *bus)
>  {
>  	struct mscc_miim_dev *miim = bus->priv;
> +	int ret;
>  
>  	if (miim->phy_regs) {
> -		writel(0, miim->phy_regs + MSCC_PHY_REG_PHY_CFG);
> -		writel(0x1ff, miim->phy_regs + MSCC_PHY_REG_PHY_CFG);
> +		ret = regmap_write(miim->phy_regs, MSCC_PHY_REG_PHY_CFG, 0);
> +		if (ret < 0) {
> +			WARN_ONCE(1, "mscc reset set error %d\n", ret);
> +			return ret;
> +		}
> +
> +		ret = regmap_write(miim->phy_regs, MSCC_PHY_REG_PHY_CFG, 0x1ff);
> +		if (ret < 0) {
> +			WARN_ONCE(1, "mscc reset clear error %d\n", ret);
> +			return ret;
> +		}
> +
>  		mdelay(500);
>  	}
>  
>  	return 0;
>  }
>  
> -static int mscc_miim_probe(struct platform_device *pdev)
> +static const struct regmap_config mscc_miim_regmap_config = {
> +	.reg_bits	= 32,
> +	.val_bits	= 32,
> +	.reg_stride	= 4,
> +};
> +
> +static int mscc_miim_setup(struct device *dev, struct mii_bus **pbus,
> +			   struct regmap *mii_regmap, struct regmap *phy_regmap)
>  {
> -	struct mscc_miim_dev *dev;
> -	struct resource *res;
> +	struct mscc_miim_dev *miim;
>  	struct mii_bus *bus;
> -	int ret;
>  
> -	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*dev));
> +	bus = devm_mdiobus_alloc_size(dev, sizeof(*miim));
>  	if (!bus)
>  		return -ENOMEM;
>  
> @@ -147,24 +190,58 @@ static int mscc_miim_probe(struct platform_device *pdev)
>  	bus->read = mscc_miim_read;
>  	bus->write = mscc_miim_write;
>  	bus->reset = mscc_miim_reset;
> -	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
> -	bus->parent = &pdev->dev;
> +	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
> +	bus->parent = dev;
> +
> +	miim = bus->priv;
> +
> +	*pbus = bus;
> +
> +	miim->regs = mii_regmap;
> +	miim->phy_regs = phy_regmap;
> +
> +	return 0;
> +}
> +
> +static int mscc_miim_probe(struct platform_device *pdev)
> +{
> +	struct regmap *mii_regmap, *phy_regmap;
> +	void __iomem *regs, *phy_regs;
> +	struct mscc_miim_dev *dev;
> +	struct mii_bus *bus;
> +	int ret;
>  
> -	dev = bus->priv;
> -	dev->regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
> -	if (IS_ERR(dev->regs)) {
> +	regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
> +	if (IS_ERR(regs)) {
>  		dev_err(&pdev->dev, "Unable to map MIIM registers\n");
> -		return PTR_ERR(dev->regs);
> +		return PTR_ERR(regs);
>  	}
>  
> -	/* This resource is optional */
> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> -	if (res) {
> -		dev->phy_regs = devm_ioremap_resource(&pdev->dev, res);
> -		if (IS_ERR(dev->phy_regs)) {
> -			dev_err(&pdev->dev, "Unable to map internal phy registers\n");
> -			return PTR_ERR(dev->phy_regs);
> -		}
> +	mii_regmap = devm_regmap_init_mmio(&pdev->dev, regs,
> +					   &mscc_miim_regmap_config);
> +
> +	if (IS_ERR(mii_regmap)) {
> +		dev_err(&pdev->dev, "Unable to create MIIM regmap\n");
> +		return PTR_ERR(mii_regmap);
> +	}
> +
> +	phy_regs = devm_platform_ioremap_resource(pdev, 1);
> +	if (IS_ERR(dev->phy_regs)) {

Oops. I'll fix this in V3.

> +		dev_err(&pdev->dev, "Unable to map internal phy registers\n");
> +		return PTR_ERR(dev->phy_regs);
> +	}
> +
> +	phy_regmap = devm_regmap_init_mmio(&pdev->dev, phy_regs,
> +					   &mscc_miim_regmap_config);
> +	if (IS_ERR(phy_regmap)) {
> +		dev_err(&pdev->dev, "Unable to create phy register regmap\n");
> +		return PTR_ERR(dev->phy_regs);
> +	}
> +
> +	ret = mscc_miim_setup(&pdev->dev, &bus, mii_regmap, phy_regmap);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Unable to setup the MDIO bus\n");
> +		return ret;
>  	}
>  
>  	ret = of_mdiobus_register(bus, pdev->dev.of_node);
> -- 
> 2.25.1
>