Re: [PATCH v10 13/15] mmc: sdhci-cadence: Add AMD Pensando Elba SoC support

[Adrian Hunter <adrian.hunter@xxxxxxxxx>]

On 6/03/23 06:07, Brad Larson wrote:
> Add support for AMD Pensando Elba SoC which explicitly
> controls byte-lane enables on writes.
> 
> Select MMC_SDHCI_IO_ACCESSORS for MMC_SDHCI_CADENCE which
> allows Elba SoC sdhci_elba_ops to overwrite the SDHCI
> IO memory accessors.
> 
> Signed-off-by: Brad Larson <blarson@xxxxxxx>

Minor comments below.  Fix those and you can add:

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
> 
> v10 changes:
> - Add Elba specific support into this 3rd patch.  This builds on the private
>   writel() enabled in patch 1 followed by platform specific init() in patch 2.
> - Specify when first used the reason for the spinlock use to order byte-enable
>   prior to write data.
> 
> ---
>  drivers/mmc/host/Kconfig         |   1 +
>  drivers/mmc/host/sdhci-cadence.c | 101 +++++++++++++++++++++++++++++++
>  2 files changed, 102 insertions(+)
> 
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 4745fe217ade..9f793892123c 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -255,6 +255,7 @@ config MMC_SDHCI_CADENCE
>  	tristate "SDHCI support for the Cadence SD/SDIO/eMMC controller"
>  	depends on MMC_SDHCI_PLTFM
>  	depends on OF
> +	select MMC_SDHCI_IO_ACCESSORS
>  	help
>  	  This selects the Cadence SD/SDIO/eMMC driver.
>  
> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
> index c528a25f48b8..31c77d32aa7d 100644
> --- a/drivers/mmc/host/sdhci-cadence.c
> +++ b/drivers/mmc/host/sdhci-cadence.c
> @@ -66,6 +66,8 @@ struct sdhci_cdns_phy_param {
>  
>  struct sdhci_cdns_priv {
>  	void __iomem *hrs_addr;
> +	void __iomem *ctl_addr;	/* write control */
> +	spinlock_t wrlock;	/* write lock */
>  	bool enhanced_strobe;
>  	void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
>  	unsigned int nr_phy_params;
> @@ -321,6 +323,94 @@ static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
>  		sdhci_set_uhs_signaling(host, timing);
>  }
>  
> +/* Elba control register bits [6:3] are byte-lane enables */
> +#define ELBA_BYTE_ENABLE_MASK(x)	((x) << 3)
> +
> +/*
> + * The Pensando Elba SoC explicitly controls byte-lane enabling on writes
> + * which includes writes to the HRS registers.  The write lock (wrlock)
> + * is used to ensure byte-lane enable, using write control (ctl_addr),
> + * occurs before the data write.
> + */
> +static void elba_priv_writel(struct sdhci_cdns_priv *priv, u32 val,
> +			     void __iomem *reg)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&priv->wrlock, flags);
> +	writel(ELBA_BYTE_ENABLE_MASK(0xf), priv->ctl_addr);
> +	writel(val, reg);
> +	spin_unlock_irqrestore(&priv->wrlock, flags);
> +}
> +
> +static void elba_write_l(struct sdhci_host *host, u32 val, int reg)
> +{
> +	elba_priv_writel(sdhci_cdns_priv(host), val, host->ioaddr + reg);
> +}
> +
> +static void elba_write_w(struct sdhci_host *host, u16 val, int reg)
> +{
> +	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +	u32 byte_enables;
> +	unsigned long flags;
> +
> +	byte_enables = GENMASK(1, 0) << (reg & 0x3);
> +	spin_lock_irqsave(&priv->wrlock, flags);
> +	writel(ELBA_BYTE_ENABLE_MASK(byte_enables), priv->ctl_addr);
> +	writew(val, host->ioaddr + reg);
> +	spin_unlock_irqrestore(&priv->wrlock, flags);
> +}
> +
> +static void elba_write_b(struct sdhci_host *host, u8 val, int reg)
> +{
> +	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +	u32 byte_enables;
> +	unsigned long flags;
> +
> +	byte_enables = BIT(0) << (reg & 0x3);
> +	spin_lock_irqsave(&priv->wrlock, flags);
> +	writel(ELBA_BYTE_ENABLE_MASK(byte_enables), priv->ctl_addr);
> +	writeb(val, host->ioaddr + reg);
> +	spin_unlock_irqrestore(&priv->wrlock, flags);
> +}
> +
> +static const struct sdhci_ops sdhci_elba_ops = {
> +	.write_l = elba_write_l,
> +	.write_w = elba_write_w,
> +	.write_b = elba_write_b,
> +	.set_clock = sdhci_set_clock,
> +	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
> +	.set_bus_width = sdhci_set_bus_width,
> +	.reset = sdhci_reset,
> +	.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
> +};
> +
> +static int elba_drv_init(struct platform_device *pdev)
> +{
> +	struct sdhci_host *host = platform_get_drvdata(pdev);
> +	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +	struct resource *iomem;
> +	void __iomem *ioaddr;
> +
> +	host->mmc->caps |= (MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA);

Unnecessary parentheses

> +
> +	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 1);

Looks like devm_platform_ioremap_resource() does that also
and will return an error if need be, so platform_get_resource()
is not needed here.

> +	if (!iomem)
> +		return -ENOMEM;
> +
> +	/* Byte-lane control register */
> +	ioaddr = devm_platform_ioremap_resource(pdev, 1);
> +	if (IS_ERR(ioaddr))
> +		return PTR_ERR(ioaddr);
> +
> +	priv->ctl_addr = ioaddr;
> +	priv->priv_writel = elba_priv_writel;
> +	spin_lock_init(&priv->wrlock);

Please move the spin_lock_init() so it happens always.

> +	writel(ELBA_BYTE_ENABLE_MASK(0xf), priv->ctl_addr);
> +
> +	return 0;
> +}
> +
>  static const struct sdhci_ops sdhci_cdns_ops = {
>  	.set_clock = sdhci_set_clock,
>  	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
> @@ -337,6 +427,13 @@ static const struct sdhci_cdns_drv_data sdhci_cdns_uniphier_drv_data = {
>  	},
>  };
>  
> +static const struct sdhci_cdns_drv_data sdhci_elba_drv_data = {
> +	.init = elba_drv_init,
> +	.pltfm_data = {
> +		.ops = &sdhci_elba_ops,
> +	},
> +};
> +
>  static const struct sdhci_cdns_drv_data sdhci_cdns_drv_data = {
>  	.pltfm_data = {
>  		.ops = &sdhci_cdns_ops,
> @@ -477,6 +574,10 @@ static const struct of_device_id sdhci_cdns_match[] = {
>  		.compatible = "socionext,uniphier-sd4hc",
>  		.data = &sdhci_cdns_uniphier_drv_data,
>  	},
> +	{
> +		.compatible = "amd,pensando-elba-sd4hc",
> +		.data = &sdhci_elba_drv_data,
> +	},
>  	{ .compatible = "cdns,sd4hc" },
>  	{ /* sentinel */ }
>  };