On 18/11/19 12:43 PM, Baolin Wang wrote:
> From: Baolin Wang <baolin.wang@xxxxxxxxxx>
>
> When using the host software queue, it will trigger the next request in
> irq handler without a context switch. But the sdhci_request() can not be
> called in interrupt context when using host software queue for some host
> drivers, due to the get_cd() ops can be sleepable.
>
> But for some host drivers, such as Spreadtrum host driver, the card is
> nonremovable, so the get_cd() ops is not sleepable, which means we can
> complete the data request and trigger the next request in irq handler
> to remove the context switch for the Spreadtrum host driver.
>
> As suggested by Adrian, we should introduce a request_atomic() API to
> indicate that a request can be called in interrupt context to remove
> the context switch when using mmc host software queue. But this should
> be done in another thread to convert the users of mmc host software queue.
> Thus we can introduce a variable in struct sdhci_host to indicate that
> we will always to defer to complete requests when using the host software
> queue.
>
> Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
> Signed-off-by: Baolin Wang <baolin.wang7@xxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 2 +-
> drivers/mmc/host/sdhci.h | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 850241f..4bef066 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3035,7 +3035,7 @@ static inline bool sdhci_defer_done(struct sdhci_host *host,
> {
> struct mmc_data *data = mrq->data;
>
> - return host->pending_reset ||
> + return host->pending_reset || host->always_defer_done ||
> ((host->flags & SDHCI_REQ_USE_DMA) && data &&
> data->host_cookie == COOKIE_MAPPED);
> }
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index d89cdb9..a73ce89 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -533,6 +533,7 @@ struct sdhci_host {
> bool pending_reset; /* Cmd/data reset is pending */
> bool irq_wake_enabled; /* IRQ wakeup is enabled */
> bool v4_mode; /* Host Version 4 Enable */
> + bool always_defer_done; /* Always defer to complete requests */
>
> struct mmc_request *mrqs_done[SDHCI_MAX_MRQS]; /* Requests done */
> struct mmc_command *cmd; /* Current command */
>
