linux-kernel - Re: [PATCH v1] sdhci: tegra: Add workaround for Broadcom WiFi

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Message-ID: <CAPDyKFpMe09PNQqinvvidF+wfASx2nuvgf7=Hx5+cGni8pdcRA@mail.gmail.com>
Date:   Wed, 11 Dec 2019 09:11:59 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        linux-tegra <linux-tegra@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] sdhci: tegra: Add workaround for Broadcom WiFi

On Tue, 10 Dec 2019 at 02:40, Dmitry Osipenko <digetx@...il.com> wrote:
>
> All Tegra20 boards that have embedded Broadcom WiFi SDIO chip are affected
> by a problem where WiFi chip reports CCCR v1.10, while it should v1.20.
> In a result high-speed mode isn't enabled for the WiFi card and this
> results in a malfunctioning SDIO communication.

Does that also mean SDIO_SPEED_SHS bit is set when reading SDIO_CCCR_SPEED?

>
>  brcmfmac: brcmf_sdio_readframes: read 304 bytes from channel 1 failed: -84
>  brcmfmac: brcmf_sdio_rxfail: abort command, terminate frame, send NAK
>
> Downstream kernels are overriding card's CCCR info in SDHCI driver to fix
> the problem, let's do the same in upstream.
>
> The change is inspired by omap_hsmmc_init_card() of OMAP's HSMMC driver,
> which overrides card's info for the TI wl1251 WiFi.

This is a temporary solution and should be replaced by doing the DT
parsing during

So, yes, let's see if we can use a card quirk instead. That's the first option.

A second option is simply to parse the DT subnode for a new DT
property during mmc_sdio_init_card(). Along the lines of what we do
for the broken-hpi DT binding for eMMC.

Kind regards
Uffe

>
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/mmc/host/sdhci-tegra.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index 7bc950520fd9..2ad87da98f2c 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -1501,6 +1501,32 @@ static int sdhci_tegra_add_host(struct sdhci_host *host)
>         return ret;
>  }
>
> +static void sdhci_tegra_init_card(struct mmc_host *mmc, struct mmc_card *card)
> +{
> +       if (card->type == MMC_TYPE_SDIO) {
> +               struct device_node *np = mmc_dev(mmc)->of_node;
> +
> +               np = of_get_compatible_child(np, "brcm,bcm4329-fmac");
> +               if (np) {
> +                       dev_info(mmc_dev(mmc), "found bcm4329\n");
> +
> +                       /*
> +                        * All Tegra20 boards that have embedded BCM4329
> +                        * chip need to enable high speed for SDIO, otherwise
> +                        * further communication with the card doesn't work
> +                        * well.
> +                        *
> +                        * Later BCM43xx chips do not need this workaround,
> +                        * but there is no good way to differentiate chip's
> +                        * version at this stage and it doesn't cause any
> +                        * harm for the later chips.
> +                        */
> +                       card->cccr.high_speed = 1;
> +                       of_node_put(np);
> +               }
> +       }
> +}
> +
>  static int sdhci_tegra_probe(struct platform_device *pdev)
>  {
>         const struct of_device_id *match;
> @@ -1545,6 +1571,8 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>                 host->mmc_host_ops.execute_tuning =
>                                 tegra_sdhci_execute_hw_tuning;
>
> +       host->mmc_host_ops.init_card = sdhci_tegra_init_card;
> +
>         rc = mmc_of_parse(host->mmc);
>         if (rc)
>                 goto err_parse_dt;
> --
> 2.24.0
>