From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH v7 3/4] mmc: host: sdhci: Add a variable to defer to complete requests if needed Date: Fri, 22 Nov 2019 14:14:38 +0200 Message-ID: <983cb2b7-7887-af86-5029-120ff6d2b839@intel.com> References: <0199b93bad45b7f1dc7751844ac8031b316b2fed.1574073572.git.baolin.wang7@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <0199b93bad45b7f1dc7751844ac8031b316b2fed.1574073572.git.baolin.wang7@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Baolin Wang , ulf.hansson@linaro.org, asutoshd@codeaurora.org Cc: orsonzhai@gmail.com, zhang.lyra@gmail.com, arnd@arndb.de, linus.walleij@linaro.org, vincent.guittot@linaro.org, baolin.wang@linaro.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-mmc@vger.kernel.org On 18/11/19 12:43 PM, Baolin Wang wrote: > From: Baolin Wang > > 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 > Signed-off-by: Baolin Wang > Signed-off-by: Baolin Wang Acked-by: Adrian Hunter > --- > 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 */ >