Re: [PATCH v5 2/3] mmc: host: sdhci: Implement the request_atomic() API

From: Adrian Hunter
Date: Tue Apr 14 2020 - 09:49:34 EST


On 13/04/20 5:46 am, Baolin Wang wrote:
> Implement the request_atomic() ops for the sdhci driver to process
> one request in the atomic context if the card is nonremovable.
>
> Moreover, we should return BUSY flag if controller has not released
> the inhibit bits to allow HSQ trying to send request again in non-atomic
> context.
>
> Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Signed-off-by: Baolin Wang <baolin.wang7@xxxxxxxxx>

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

> ---
> drivers/mmc/host/sdhci.c | 34 ++++++++++++++++++++++++++++++++++
> drivers/mmc/host/sdhci.h | 1 +
> 2 files changed, 35 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 10b9570f48aa..0baef595de26 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2144,6 +2144,40 @@ void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> }
> EXPORT_SYMBOL_GPL(sdhci_request);
>
> +int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct mmc_command *cmd;
> + unsigned long flags;
> + int ret = 0;
> +
> + spin_lock_irqsave(&host->lock, flags);
> +
> + if (sdhci_present_error(host, mrq->cmd, true)) {
> + sdhci_finish_mrq(host, mrq);
> + goto out_finish;
> + }
> +
> + cmd = sdhci_manual_cmd23(host, mrq) ? mrq->sbc : mrq->cmd;
> +
> + /*
> + * The HSQ may send a command in interrupt context without polling
> + * the busy signaling, which means we should return BUSY if controller
> + * has not released inhibit bits to allow HSQ trying to send request
> + * again in non-atomic context. So we should not finish this request
> + * here.
> + */
> + if (!sdhci_send_command(host, cmd))
> + ret = -EBUSY;
> + else
> + sdhci_led_activate(host);
> +
> +out_finish:
> + spin_unlock_irqrestore(&host->lock, flags);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(sdhci_request_atomic);
> +
> void sdhci_set_bus_width(struct sdhci_host *host, int width)
> {
> u8 ctrl;
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index a7e469c00617..4bd70da7aa00 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -776,6 +776,7 @@ void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
> void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
> unsigned short vdd);
> void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq);
> +int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq);
> void sdhci_set_bus_width(struct sdhci_host *host, int width);
> void sdhci_reset(struct sdhci_host *host, u8 mask);
> void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
>