Re: [PATCH v13 13/15] mmc: sdhci-cadence: Add AMD Pensando Elba SoC support

[Ulf Hansson <ulf.hansson@xxxxxxxxxx>]

On Mon, 10 Apr 2023 at 20:47, Brad Larson <blarson@xxxxxxx> 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>
> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

Applied for next, thanks!

Kind regards
Uffe


> ---
>
> v13 changes:
> - Use GENMASK(7, 3) in elba_priv_writel() to set all byte enables
> - Add a variable 'shift' with GENMASK(1, 0) in elba_write_w() and
>   elba_write_b() to set the byte enable variable.
>
> v11 changes:
> - Remove elba-drv_init() call to platform_get_resource() since that
>   check is done inside devm_platform_ioremap_resource()
> - Move spin_lock_init() before error check
> - Remove extra parentheses
>
> 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 | 98 ++++++++++++++++++++++++++++++++
>  2 files changed, 99 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..5d1e9cef74f5 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 +323,91 @@ 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(GENMASK(7, 3), 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 shift = reg & GENMASK(1, 0);
> +       unsigned long flags;
> +       u32 byte_enables;
> +
> +       byte_enables = GENMASK(1, 0) << shift;
> +       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 shift = reg & GENMASK(1, 0);
> +       unsigned long flags;
> +       u32 byte_enables;
> +
> +       byte_enables = BIT(0) << shift;
> +       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);
> +       void __iomem *ioaddr;
> +
> +       host->mmc->caps |= MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA;
> +       spin_lock_init(&priv->wrlock);
> +
> +       /* 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;
> +       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 +424,13 @@ 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 +571,10 @@ 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 */ }
>  };
> --
> 2.17.1
>