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References: <20210329015938.20316-1-brad@pensando.io> <20210329015938.20316-6-brad@pensando.io>
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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Tue, 30 Mar 2021 12:30:26 +0200
Message-ID: <CAPDyKFpg1qJD0r54sBC3hCoFey_+gwAL1n2o-aGwnAzAan5p7w@mail.gmail.com>
Subject: Re: [PATCH v2 05/13] mmc: sdhci-cadence: Add Pensando Elba SoC support
To:     Brad Larson <brad@pensando.io>
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        linux-mmc <linux-mmc@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

+ Masahiro Yamada (main author of the driver)

On Mon, 29 Mar 2021 at 03:59, Brad Larson <brad@pensando.io> wrote:
>
> Add support for Pensando Elba SoC which explicitly controls
> byte-lane enables on writes.  Refactor to allow platform
> specific write ops.
>
> Signed-off-by: Brad Larson <brad@pensando.io>
> ---
>  drivers/mmc/host/Kconfig              |  15 +++
>  drivers/mmc/host/Makefile             |   1 +
>  drivers/mmc/host/sdhci-cadence-elba.c | 137 ++++++++++++++++++++++++++

By looking at the amount of code changes that seem to be needed to
support the Pensando Elba variant, I don't think it's necessary to
split this into a separate file.

Unless Yamada-san has a different opinion, I would rather just stick
with using sdhci-cadence.c.

>  drivers/mmc/host/sdhci-cadence.c      |  81 ++++++++-------
>  drivers/mmc/host/sdhci-cadence.h      |  68 +++++++++++++
>  5 files changed, 260 insertions(+), 42 deletions(-)
>  create mode 100644 drivers/mmc/host/sdhci-cadence-elba.c
>  create mode 100644 drivers/mmc/host/sdhci-cadence.h
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index b236dfe2e879..65ea323c06f2 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -250,6 +250,21 @@ config MMC_SDHCI_CADENCE
>
>           If unsure, say N.
>
> +config MMC_SDHCI_CADENCE_ELBA
> +       tristate "SDHCI support for the Pensando/Cadence SD/SDIO/eMMC controller"
> +       depends on ARCH_PENSANDO_ELBA_SOC
> +       depends on MMC_SDHCI
> +       depends on OF
> +       depends on MMC_SDHCI_CADENCE
> +       depends on MMC_SDHCI_PLTFM
> +       select MMC_SDHCI_IO_ACCESSORS

According to the comment above - then you should probably just extend
the conditions for when building MMC_SDHCI_CADENCE, rather than having
to add a new Kconfig for "*_ELBA".

> +       help
> +         This selects the Pensando/Cadence SD/SDIO/eMMC controller.
> +
> +         If you have a controller with this interface, say Y or M here.
> +
> +         If unsure, say N.
> +
>  config MMC_SDHCI_CNS3XXX
>         tristate "SDHCI support on the Cavium Networks CNS3xxx SoC"
>         depends on ARCH_CNS3XXX || COMPILE_TEST
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index 6df5c4774260..f2a6d50e64de 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -80,6 +80,7 @@ obj-$(CONFIG_MMC_REALTEK_USB) += rtsx_usb_sdmmc.o
>
>  obj-$(CONFIG_MMC_SDHCI_PLTFM)          += sdhci-pltfm.o
>  obj-$(CONFIG_MMC_SDHCI_CADENCE)                += sdhci-cadence.o
> +obj-$(CONFIG_MMC_SDHCI_CADENCE_ELBA)   += sdhci-cadence-elba.o
>  obj-$(CONFIG_MMC_SDHCI_CNS3XXX)                += sdhci-cns3xxx.o
>  obj-$(CONFIG_MMC_SDHCI_ESDHC_MCF)       += sdhci-esdhc-mcf.o
>  obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX)      += sdhci-esdhc-imx.o
> diff --git a/drivers/mmc/host/sdhci-cadence-elba.c b/drivers/mmc/host/sdhci-cadence-elba.c
> new file mode 100644
> index 000000000000..ec23f43de407
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-cadence-elba.c
> @@ -0,0 +1,137 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2020 Pensando Systems, Inc.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/mmc.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +
> +#include "sdhci-pltfm.h"
> +#include "sdhci-cadence.h"
> +
> +// delay regs address

Please don't use "//" when adding comments, but instead "/* ... */".
This applies to several more places of the patch.

> +#define SDIO_REG_HRS4          0x10
> +#define REG_DELAY_HS           0x00
> +#define REG_DELAY_DEFAULT      0x01
> +#define REG_DELAY_UHSI_SDR50   0x04
> +#define REG_DELAY_UHSI_DDR50   0x05
> +
> +static void elba_write_l(struct sdhci_host *host, u32 val, int reg)
> +{
> +       struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&priv->wrlock, flags);
> +       writel(0x78, priv->ctl_addr);
> +       writel(val, host->ioaddr + reg);
> +       spin_unlock_irqrestore(&priv->wrlock, flags);
> +}
> +
> +static void elba_write_w(struct sdhci_host *host, u16 val, int reg)
> +{
> +       struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +       unsigned long flags;
> +       u32 m = (reg & 0x3);
> +       u32 msk = (0x3 << (m));
> +
> +       spin_lock_irqsave(&priv->wrlock, flags);
> +       writel(msk << 3, 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);
> +       unsigned long flags;
> +       u32 m = (reg & 0x3);
> +       u32 msk = (0x1 << (m));
> +
> +       spin_lock_irqsave(&priv->wrlock, flags);
> +       writel(msk << 3, priv->ctl_addr);
> +       writeb(val, host->ioaddr + reg);
> +       spin_unlock_irqrestore(&priv->wrlock, flags);
> +}
> +
> +static void elba_priv_write_l(struct sdhci_cdns_priv *priv,
> +               u32 val, void __iomem *reg)
> +{
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&priv->wrlock, flags);
> +       writel(0x78, priv->ctl_addr);
> +       writel(val, 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 void sd4_set_dlyvr(struct sdhci_host *host,
> +                         unsigned char addr, unsigned char data)

Please, try to think of a better function name that's more
descriptive. Moreover, please use a common prefix for functions that
is used on elba.

> +{
> +       unsigned long dlyrv_reg;
> +
> +       dlyrv_reg = ((unsigned long)data << 8);
> +       dlyrv_reg |= addr;
> +
> +       // set data and address
> +       writel(dlyrv_reg, host->ioaddr + SDIO_REG_HRS4);
> +       dlyrv_reg |= (1uL << 24uL);
> +       // send write request
> +       writel(dlyrv_reg, host->ioaddr + SDIO_REG_HRS4);
> +       dlyrv_reg &= ~(1uL << 24);
> +       // clear write request
> +       writel(dlyrv_reg, host->ioaddr + SDIO_REG_HRS4);
> +}
> +
> +static void phy_config(struct sdhci_host *host)

Ditto.

> +{
> +       sd4_set_dlyvr(host, REG_DELAY_DEFAULT, 0x04);
> +       sd4_set_dlyvr(host, REG_DELAY_HS, 0x04);
> +       sd4_set_dlyvr(host, REG_DELAY_UHSI_SDR50, 0x06);
> +       sd4_set_dlyvr(host, REG_DELAY_UHSI_DDR50, 0x16);
> +}
> +
> +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);
> +       iomem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +       if (!iomem)
> +               return -ENOMEM;
> +       ioaddr = devm_ioremap_resource(&pdev->dev, iomem);
> +       if (IS_ERR(ioaddr))
> +               return PTR_ERR(ioaddr);
> +       priv->ctl_addr = ioaddr;
> +       priv->priv_write_l = elba_priv_write_l;
> +       spin_lock_init(&priv->wrlock);
> +       writel(0x78, priv->ctl_addr);
> +       phy_config(host);
> +       return 0;
> +}
> +
> +const struct sdhci_cdns_drv_data sdhci_elba_drv_data = {
> +       .init = elba_drv_init,
> +       .pltfm_data = {
> +               .ops = &sdhci_elba_ops,
> +       },
> +};
> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
> index 6f2de54a5987..d1ae996c3824 100644
> --- a/drivers/mmc/host/sdhci-cadence.c
> +++ b/drivers/mmc/host/sdhci-cadence.c
> @@ -14,6 +14,7 @@
>  #include <linux/of_device.h>
>
>  #include "sdhci-pltfm.h"
> +#include "sdhci-cadence.h"
>
>  /* HRS - Host Register Set (specific to Cadence) */
>  #define SDHCI_CDNS_HRS04               0x10            /* PHY access port */
> @@ -59,23 +60,6 @@
>   */
>  #define SDHCI_CDNS_MAX_TUNING_LOOP     40
>
> -struct sdhci_cdns_phy_param {
> -       u8 addr;
> -       u8 data;
> -};
> -
> -struct sdhci_cdns_priv {
> -       void __iomem *hrs_addr;
> -       bool enhanced_strobe;
> -       unsigned int nr_phy_params;
> -       struct sdhci_cdns_phy_param phy_params[];
> -};
> -
> -struct sdhci_cdns_phy_cfg {
> -       const char *property;
> -       u8 addr;
> -};
> -
>  static const struct sdhci_cdns_phy_cfg sdhci_cdns_phy_cfgs[] = {
>         { "cdns,phy-input-delay-sd-highspeed", SDHCI_CDNS_PHY_DLY_SD_HS, },
>         { "cdns,phy-input-delay-legacy", SDHCI_CDNS_PHY_DLY_SD_DEFAULT, },
> @@ -104,17 +88,17 @@ static int sdhci_cdns_write_phy_reg(struct sdhci_cdns_priv *priv,
>
>         tmp = FIELD_PREP(SDHCI_CDNS_HRS04_WDATA, data) |
>               FIELD_PREP(SDHCI_CDNS_HRS04_ADDR, addr);
> -       writel(tmp, reg);
> +       sdhci_cdns_priv_writel(priv, tmp, reg);
>
>         tmp |= SDHCI_CDNS_HRS04_WR;
> -       writel(tmp, reg);
> +       sdhci_cdns_priv_writel(priv, tmp, reg);
>
>         ret = readl_poll_timeout(reg, tmp, tmp & SDHCI_CDNS_HRS04_ACK, 0, 10);
>         if (ret)
>                 return ret;
>
>         tmp &= ~SDHCI_CDNS_HRS04_WR;
> -       writel(tmp, reg);
> +       sdhci_cdns_priv_writel(priv, tmp, reg);
>
>         ret = readl_poll_timeout(reg, tmp, !(tmp & SDHCI_CDNS_HRS04_ACK),
>                                  0, 10);
> @@ -167,14 +151,7 @@ static int sdhci_cdns_phy_init(struct sdhci_cdns_priv *priv)
>         return 0;
>  }
>
> -static void *sdhci_cdns_priv(struct sdhci_host *host)
> -{
> -       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> -
> -       return sdhci_pltfm_priv(pltfm_host);
> -}
> -
> -static unsigned int sdhci_cdns_get_timeout_clock(struct sdhci_host *host)
> +unsigned int sdhci_cdns_get_timeout_clock(struct sdhci_host *host)
>  {
>         /*
>          * Cadence's spec says the Timeout Clock Frequency is the same as the
> @@ -191,7 +168,7 @@ static void sdhci_cdns_set_emmc_mode(struct sdhci_cdns_priv *priv, u32 mode)
>         tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
>         tmp &= ~SDHCI_CDNS_HRS06_MODE;
>         tmp |= FIELD_PREP(SDHCI_CDNS_HRS06_MODE, mode);
> -       writel(tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
> +       sdhci_cdns_priv_writel(priv, tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
>  }
>
>  static u32 sdhci_cdns_get_emmc_mode(struct sdhci_cdns_priv *priv)
> @@ -223,7 +200,7 @@ static int sdhci_cdns_set_tune_val(struct sdhci_host *host, unsigned int val)
>          */
>         for (i = 0; i < 2; i++) {
>                 tmp |= SDHCI_CDNS_HRS06_TUNE_UP;
> -               writel(tmp, reg);
> +               sdhci_cdns_priv_writel(priv, tmp, reg);
>
>                 ret = readl_poll_timeout(reg, tmp,
>                                          !(tmp & SDHCI_CDNS_HRS06_TUNE_UP),
> @@ -272,10 +249,13 @@ static int sdhci_cdns_execute_tuning(struct sdhci_host *host, u32 opcode)
>                 return -EIO;
>         }
>
> +       dev_info(mmc_dev(host->mmc), "tuning val %d streak end %d max %d\n",
> +                end_of_streak - max_streak / 2, end_of_streak, max_streak);
> +
>         return sdhci_cdns_set_tune_val(host, end_of_streak - max_streak / 2);
>  }
>
> -static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
> +void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
>                                          unsigned int timing)
>  {
>         struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> @@ -318,13 +298,17 @@ static const struct sdhci_ops sdhci_cdns_ops = {
>         .set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
>  };
>
> -static const struct sdhci_pltfm_data sdhci_cdns_uniphier_pltfm_data = {
> -       .ops = &sdhci_cdns_ops,
> -       .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
> +static const struct sdhci_cdns_drv_data sdhci_cdns_uniphier_drv_data = {
> +       .pltfm_data = {
> +               .ops = &sdhci_cdns_ops,
> +               .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
> +       },
>  };
>
> -static const struct sdhci_pltfm_data sdhci_cdns_pltfm_data = {
> -       .ops = &sdhci_cdns_ops,
> +static const struct sdhci_cdns_drv_data sdhci_cdns_drv_data = {
> +       .pltfm_data = {
> +               .ops = &sdhci_cdns_ops,
> +       },
>  };
>
>  static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
> @@ -350,7 +334,7 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
>  static int sdhci_cdns_probe(struct platform_device *pdev)
>  {
>         struct sdhci_host *host;
> -       const struct sdhci_pltfm_data *data;
> +       const struct sdhci_cdns_drv_data *data;
>         struct sdhci_pltfm_host *pltfm_host;
>         struct sdhci_cdns_priv *priv;
>         struct clk *clk;
> @@ -369,10 +353,10 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>
>         data = of_device_get_match_data(dev);
>         if (!data)
> -               data = &sdhci_cdns_pltfm_data;
> +               data = &sdhci_cdns_drv_data;
>
>         nr_phy_params = sdhci_cdns_phy_param_count(dev->of_node);
> -       host = sdhci_pltfm_init(pdev, data,
> +       host = sdhci_pltfm_init(pdev, &data->pltfm_data,
>                                 struct_size(priv, phy_params, nr_phy_params));
>         if (IS_ERR(host)) {
>                 ret = PTR_ERR(host);
> @@ -389,11 +373,18 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>         host->ioaddr += SDHCI_CDNS_SRS_BASE;
>         host->mmc_host_ops.hs400_enhanced_strobe =
>                                 sdhci_cdns_hs400_enhanced_strobe;
> -       sdhci_enable_v4_mode(host);
> -       __sdhci_read_caps(host, &version, NULL, NULL);
>
>         sdhci_get_of_property(pdev);
>
> +       if (data->init) {
> +               ret = data->init(pdev);
> +               if (ret)
> +                       goto free;
> +       }
> +
> +       sdhci_enable_v4_mode(host);
> +       __sdhci_read_caps(host, &version, NULL, NULL);
> +
>         ret = mmc_of_parse(host->mmc);
>         if (ret)
>                 goto free;
> @@ -453,8 +444,14 @@ static const struct dev_pm_ops sdhci_cdns_pm_ops = {
>  static const struct of_device_id sdhci_cdns_match[] = {
>         {
>                 .compatible = "socionext,uniphier-sd4hc",
> -               .data = &sdhci_cdns_uniphier_pltfm_data,
> +               .data = &sdhci_cdns_uniphier_drv_data,
>         },
> +#ifdef CONFIG_MMC_SDHCI_CADENCE_ELBA

No need to hide this minor piece of code behind ifdefs.

> +       {
> +               .compatible = "pensando,elba-emmc",
> +               .data = &sdhci_elba_drv_data
> +       },
> +#endif
>         { .compatible = "cdns,sd4hc" },
>         { /* sentinel */ }
>  };
> diff --git a/drivers/mmc/host/sdhci-cadence.h b/drivers/mmc/host/sdhci-cadence.h
> new file mode 100644
> index 000000000000..bf48e8d13430
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-cadence.h

This new header file can go away too, if you fold in all the code in
the common c-file.

> @@ -0,0 +1,68 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2016 Socionext Inc.
> + *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
> + */
> +
> +#ifndef _SDHCI_CADENCE_H_
> +#define _SDHCI_CADENCE_H_
> +
> +struct sdhci_cdns_phy_param {
> +       u8 addr;
> +       u8 data;
> +};
> +
> +struct sdhci_cdns_priv {
> +       void __iomem *hrs_addr;
> +#ifdef CONFIG_MMC_SDHCI_CADENCE_ELBA
> +       void __iomem *ctl_addr; /* write control */
> +       spinlock_t wrlock;      /* write lock */
> +#endif
> +       bool enhanced_strobe;
> +       void (*priv_write_l)(struct sdhci_cdns_priv *priv, u32 val,
> +                            void __iomem *reg); /* for cadence-elba.c */
> +       unsigned int nr_phy_params;
> +       struct sdhci_cdns_phy_param phy_params[];
> +};
> +
> +struct sdhci_cdns_phy_cfg {
> +       const char *property;
> +       u8 addr;
> +};
> +
> +struct sdhci_cdns_drv_data {
> +       int (*init)(struct platform_device *pdev);
> +       const struct sdhci_pltfm_data pltfm_data;
> +};
> +
> +static inline void *sdhci_cdns_priv(struct sdhci_host *host)
> +{
> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +
> +       return sdhci_pltfm_priv(pltfm_host);
> +}
> +
> +/*
> + * The Pensando Elba SoC explicitly controls byte-lane enables on writes,
> + * which includes writes to the HRS registers.
> + * sdhci_cdns_priv_writel() is used in the common sdhci-cadence.c code
> + * to write HRS registers, and this function dispatches to the specific
> + * code.
> + */
> +static inline void sdhci_cdns_priv_writel(struct sdhci_cdns_priv *priv,
> +               u32 val, void __iomem *reg)
> +{
> +       if (unlikely(priv->priv_write_l))
> +               priv->priv_write_l(priv, val, reg);
> +       else
> +               writel(val, reg);
> +}
> +
> +#ifdef CONFIG_MMC_SDHCI_CADENCE_ELBA
> +extern const struct sdhci_cdns_drv_data sdhci_elba_drv_data;
> +#endif
> +
> +unsigned int sdhci_cdns_get_timeout_clock(struct sdhci_host *host);
> +void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host, unsigned int timing);
> +
> +#endif

Kind regards
Uffe