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

From: Ulf Hansson
Date: Wed Dec 11 2019 - 03:12:38 EST


On Tue, 10 Dec 2019 at 02:40, Dmitry Osipenko <digetx@xxxxxxxxx> 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@xxxxxxxxx>
> ---
> 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
>