linux-kernel - Re: [PATCH v5 2/3] mmc: host: sdhci: Implement the request

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Message-ID: <9d118792-8551-7988-464e-162550bc6614@intel.com>
Date:   Tue, 14 Apr 2020 16:47:55 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Baolin Wang <baolin.wang7@...il.com>, ulf.hansson@...aro.org
Cc:     arnd@...db.de, orsonzhai@...il.com, zhang.lyra@...il.com,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/3] mmc: host: sdhci: Implement the request_atomic()
 API

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@...el.com>
> Signed-off-by: Baolin Wang <baolin.wang7@...il.com>

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

> ---
>  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);
>