linux-kernel - Re: [PATCH V2 2/4] mmc: sdhci-msm: Add msm version specific ops and data structures

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Date:   Tue, 12 Jun 2018 16:36:26 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Vijay Viswanath <vviswana@...eaurora.org>, adrian.hunter@...el.com,
        mark.rutland@....com, robh+dt@...nel.org, ulf.hansson@...aro.org
Cc:     linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        shawn.lin@...k-chips.com, linux-arm-msm@...r.kernel.org,
        georgi.djakov@...aro.org, devicetree@...r.kernel.org,
        asutoshd@...eaurora.org, stummala@...eaurora.org,
        venkatg@...eaurora.org, jeremymc@...hat.com,
        vviswana@...eaurora.org, bjorn.andersson@...aro.org,
        riteshh@...eaurora.org, vbadigan@...eaurora.org,
        dianders@...gle.com, sayalil@...eaurora.org
Subject: Re: [PATCH V2 2/4] mmc: sdhci-msm: Add msm version specific ops and data
 structures

Quoting Vijay Viswanath (2018-05-29 02:52:39)
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 4050c99..2a66aa0 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -226,6 +226,24 @@ struct sdhci_msm_offset {
>         .core_ddr_config_2 = 0x1bc,
>  };
>  
> +struct sdhci_msm_variant_ops {
> +       u8 (*msm_readb_relaxed)(struct sdhci_host *host, u32 offset);
> +       u32 (*msm_readl_relaxed)(struct sdhci_host *host, u32 offset);
> +       void (*msm_writeb_relaxed)(u8 val, struct sdhci_host *host, u32 offset);
> +       void (*msm_writel_relaxed)(u32 val, struct sdhci_host *host,
> +                       u32 offset);
> +};
> +
> +/*
> + * From V5, register spaces have changed. Wrap this info in a structure
> + * and choose the data_structure based on version info mentioned in DT.
> + */

This is sort of odd. Usually we have a read/write function that swizzles
based on register variants, and that's contained with that function. Now
it's the other way.

> +struct sdhci_msm_variant_info {
> +       bool mci_removed;
> +       const struct sdhci_msm_variant_ops *var_ops;
> +       const struct sdhci_msm_offset *offset;
> +};
> +
>  struct sdhci_msm_host {
>         struct platform_device *pdev;
>         void __iomem *core_mem; /* MSM SDCC mapped address */
> @@ -245,8 +263,45 @@ struct sdhci_msm_host {
>         wait_queue_head_t pwr_irq_wait;
>         bool pwr_irq_flag;
>         u32 caps_0;
> +       bool mci_removed;
> +       const struct sdhci_msm_variant_ops *var_ops;
> +       const struct sdhci_msm_offset *offset;
>  };
>  
> +/*
> + * APIs to read/write to vendor specific registers which were there in the
> + * core_mem region before MCI was removed.
> + */
> +static u32 sdhci_msm_mci_variant_readl_relaxed(struct sdhci_host *host,
> +               u32 offset)
> +{
> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +       struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> +
> +       return readl_relaxed(msm_host->core_mem + offset);

Is core_mem assigned in the new hardware? Maybe that needs to be
'repurposed' for vendor specific registers on v5 and renamed to
something like msm_host::vendor_base or something like that.

> +}
> +
> +static u32 sdhci_msm_v5_variant_readl_relaxed(struct sdhci_host *host,
> +               u32 offset)
> +{
> +       return readl_relaxed(host->ioaddr + offset);
> +}
> +
> +static void sdhci_msm_mci_variant_writel_relaxed(u32 val,
> +               struct sdhci_host *host, u32 offset)
> +{
> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +       struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> +
> +       writel_relaxed(val, msm_host->core_mem + offset);
> +}
> +
> +static void sdhci_msm_v5_variant_writel_relaxed(u32 val,
> +               struct sdhci_host *host, u32 offset)
> +{
> +       writel_relaxed(val, host->ioaddr + offset);
> +}
> +
>  static unsigned int msm_get_clock_rate_for_bus_mode(struct sdhci_host *host,
>                                                     unsigned int clock)
>  {
> @@ -1481,6 +1536,28 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
>         pr_debug("%s: supported caps: 0x%08x\n", mmc_hostname(mmc), caps);
>  }
>  
> +static const struct sdhci_msm_variant_ops mci_var_ops = {
> +       .msm_readl_relaxed = sdhci_msm_mci_variant_readl_relaxed,
> +       .msm_writel_relaxed = sdhci_msm_mci_variant_writel_relaxed,
> +};
> +
> +static const struct sdhci_msm_variant_ops v5_var_ops = {
> +       .msm_readl_relaxed = sdhci_msm_v5_variant_readl_relaxed,
> +       .msm_writel_relaxed = sdhci_msm_v5_variant_writel_relaxed,
> +};
> +
> +static const struct sdhci_msm_variant_info sdhci_msm_mci_var = {
> +       .mci_removed = 0,

Please use true and false instead of 0 and 1 when the type is bool.

> +       .var_ops = &mci_var_ops,
> +       .offset = &sdhci_msm_mci_offset,
> +};
> +
> +static const struct sdhci_msm_variant_info sdhci_msm_v5_var = {
> +       .mci_removed = 1,
> +       .var_ops = &v5_var_ops,
> +       .offset = &sdhci_msm_v5_offset,
> +};