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References: <20190829104928.27404-1-yamada.masahiro@socionext.com>
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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Thu, 29 Aug 2019 13:47:47 +0200
Message-ID: <CAPDyKFooFQgBgK3N1Ob9rsT_7-5kqC9i7PeMxkkeAbnDP+Fwnw@mail.gmail.com>
Subject: Re: [PATCH 1/3] mmc: sdhci-cadence: enable v4_mode to fix ADMA 64-bit addressing
To:     Masahiro Yamada <yamada.masahiro@socionext.com>
Cc:     "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Piotr Sroka <piotrs@cadence.com>,
        "# 4.0+" <stable@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, 29 Aug 2019 at 12:49, Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> The IP datasheet says this controller is compatible with SD Host
> Specification Version v4.00.
>
> As it turned out, the ADMA of this IP does not work with 64-bit mode
> when it is in the Version 3.00 compatible mode; it understands the
> old 64-bit descriptor table (as defined in SDHCI v2), but the ADMA
> System Address Register (SDHCI_ADMA_ADDRESS) cannot point to the
> 64-bit address.
>
> I noticed this issue only after commit bd2e75633c80 ("dma-contiguous:
> use fallback alloc_pages for single pages"). Prior to that commit,
> dma_set_mask_and_coherent() returned the dma address that fits in
> 32-bit range, at least for the default arm64 configuration
> (arch/arm64/configs/defconfig). Now the host->adma_addr exceeds the
> 32-bit limit, causing the real problem for the Socionext SoCs.
> (As a side-note, I was also able to reproduce the issue for older
> kernels by turning off CONFIG_DMA_CMA.)
>
> Call sdhci_enable_v4_mode() to fix this.
>
> I think it is better to back-port this, but only possible for v4.20+.
>
> When this driver was merged (v4.10), the v4 mode support did not exist.
> It was added by commit b3f80b434f72 ("mmc: sdhci: Add sd host v4 mode")
> i.e. v4.20.
>
> Cc: <stable@vger.kernel.org> # v4.20+
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Applied for fixes, by adding below tag, thanks!

Fixes: b3f80b434f72 ("mmc: sdhci: Add sd host v4 mode")

Kind regards
Uffe

> ---
>
>  drivers/mmc/host/sdhci-cadence.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
> index 163d1cf4367e..44139fceac24 100644
> --- a/drivers/mmc/host/sdhci-cadence.c
> +++ b/drivers/mmc/host/sdhci-cadence.c
> @@ -369,6 +369,7 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>         host->mmc_host_ops.execute_tuning = sdhci_cdns_execute_tuning;
>         host->mmc_host_ops.hs400_enhanced_strobe =
>                                 sdhci_cdns_hs400_enhanced_strobe;
> +       sdhci_enable_v4_mode(host);
>
>         sdhci_get_of_property(pdev);
>
> --
> 2.17.1
>