Re: [PATCH v2 1/3] mmc: sdhci-of-arasan: Add DTS property to disable DCMDs.

Adrian Hunter
2019-03-08T12:47:19Z

On 7/03/19 10:43 AM, Christoph Muellner wrote:
> Direct commands (DCMDs) are an optional feature of eMMC 5.1's command
> queue engine (CQE). The Arasan eMMC 5.1 controller uses the CQHCI,
> which exposes a control register bit to enable the feature.
> The current implementation sets this bit unconditionally.
>
> This patch allows to suppress the feature activation,
> by specifying the property disable-cqe-dcmd.
>
> Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
> Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
> drivers/mmc/host/sdhci-of-arasan.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index c9e3e050ccc8..88dc3f00a5be 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -832,7 +832,10 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
> host->mmc_host_ops.start_signal_voltage_switch =
> sdhci_arasan_voltage_switch;
> sdhci_arasan->has_cqe = true;
> - host->mmc->caps2 |= MMC_CAP2_CQE | MMC_CAP2_CQE_DCMD;
> + host->mmc->caps2 |= MMC_CAP2_CQE;
> +
> + if (!of_property_read_bool(np, "disable-cqe-dcmd"))
> + host->mmc->caps2 |= MMC_CAP2_CQE_DCMD;
> }
>
> ret = sdhci_arasan_add_host(sdhci_arasan);
>