On 6/11/19 12:48 PM, Baolin Wang wrote:
> On Wed, 6 Nov 2019 at 18:10, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>>
>> On 29/10/19 7:43 AM, Baolin Wang wrote:
>>> 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.
>>>
>>> Thus we still need introduce a variable in struct sdhci_host to indicate
>>> that we will always to defer to complete data requests if the sdhci_request()
>>> can not be called in interrupt context for some host drivers, when using
>>> the host software queue.
>>>
>>> Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>>> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
>>> ---
>>> 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..9cf2130 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 && data) ||
To move ahead in the meantime without a new host API, just defer always i.e.
+ return host->pending_reset || host->always_defer_done ||
>>
>> I didn't realize you still wanted to call the request function in interrupt
>> context. In my view that needs a new host API
>> i.e. int (*request_atomic)(struct mmc_host *mmc, struct mmc_request *mrq)
>
> Actually there are no documentation said that the
> mmc_host_ops->request() is a sleepable API, so I introduce a
> host->always_defer_done flag to decide if the request can be called in
> interrupt context or not, since for some host drivers, the request()
> implementation can be called in interrupt context.
>
> Yes, I agree a new host API is more reasonable, if you do not like the
> current approach, I can add new patches to introduce the new
> request_atomic() API. But can I create another separate patch set to
> do this? since in this patch set, the Spreadtrum host driver's
> request() implementation can be called in interrupt context. Or you
> still want these changes introducing new request_atomic() can be done
> in this patch set? Thanks.
>
>>
>>> ((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..38fbd18 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 data requests */
>>>
>>> struct mmc_request *mrqs_done[SDHCI_MAX_MRQS]; /* Requests done */
>>> struct mmc_command *cmd; /* Current command */
>>>
>>
>
>
