Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753823Ab1FVIpU (ORCPT ); Wed, 22 Jun 2011 04:45:20 -0400 Received: from mail-qy0-f174.google.com ([209.85.216.174]:45460 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751398Ab1FVIpR convert rfc822-to-8bit (ORCPT ); Wed, 22 Jun 2011 04:45:17 -0400 MIME-Version: 1.0 In-Reply-To: References: <1308699521-20556-1-git-send-email-per.forlin@linaro.org> <1308699521-20556-2-git-send-email-per.forlin@linaro.org> Date: Wed, 22 Jun 2011 10:45:16 +0200 Message-ID: Subject: Re: [PATCH v7 01/11] mmc: add non-blocking mmc request function From: Per Forlin To: Venkatraman S Cc: linaro-dev@lists.linaro.org, Nicolas Pitre , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, Chris Ball Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5898 Lines: 140 On 22 June 2011 09:42, Venkatraman S wrote: > On Wed, Jun 22, 2011 at 5:08 AM, Per Forlin wrote: >> Previously there has only been one function mmc_wait_for_req() >> to start and wait for a request. This patch adds >> ?* mmc_start_req() - starts a request wihtout waiting >> ? If there is on ongoing request wait for completion >> ? of that request and start the new one and return. >> ? Does not wait for the new command to complete. >> >> This patch also adds new function members in struct mmc_host_ops >> only called from core.c >> ?* pre_req - asks the host driver to prepare for the next job >> ?* post_req - asks the host driver to clean up after a completed job >> >> The intention is to use pre_req() and post_req() to do cache maintenance >> while a request is active. pre_req() can be called while a request is active >> to minimize latency to start next job. post_req() can be used after the next >> job is started to clean up the request. This will minimize the host driver >> request end latency. post_req() is typically used before ending the block >> request and handing over the buffer to the block layer. >> >> Add a host-private member in mmc_data to be used by >> pre_req to mark the data. The host driver will then >> check this mark to see if the data is prepared or not. >> >> Signed-off-by: Per Forlin >> --- >> ?drivers/mmc/core/core.c ?| ?110 +++++++++++++++++++++++++++++++++++++++++---- >> ?include/linux/mmc/core.h | ? ?6 ++- >> ?include/linux/mmc/host.h | ? 21 +++++++++ >> ?3 files changed, 126 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c >> index 68091dd..c82fa3b 100644 >> --- a/drivers/mmc/core/core.c >> +++ b/drivers/mmc/core/core.c >> @@ -198,9 +198,106 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) >> >> ?static void mmc_wait_done(struct mmc_request *mrq) >> ?{ >> - ? ? ? complete(mrq->done_data); >> + ? ? ? complete(&mrq->completion); >> ?} >> >> +static void __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq) >> +{ >> + ? ? ? init_completion(&mrq->completion); >> + ? ? ? mrq->done = mmc_wait_done; >> + ? ? ? mmc_start_request(host, mrq); >> +} >> + >> +static void mmc_wait_for_req_done(struct mmc_host *host, >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct mmc_request *mrq) >> +{ >> + ? ? ? wait_for_completion(&mrq->completion); >> +} >> + >> +/** >> + * ? ? mmc_pre_req - Prepare for a new request >> + * ? ? @host: MMC host to prepare command >> + * ? ? @mrq: MMC request to prepare for >> + * ? ? @is_first_req: true if there is no previous started request >> + * ? ? ? ? ? ? ? ? ? ? that may run in parellel to this call, otherwise false >> + * >> + * ? ? mmc_pre_req() is called in prior to mmc_start_req() to let >> + * ? ? host prepare for the new request. Preparation of a request may be >> + * ? ? performed while another request is running on the host. >> + */ >> +static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq, >> + ? ? ? ? ? ? ? ?bool is_first_req) >> +{ >> + ? ? ? if (host->ops->pre_req) >> + ? ? ? ? ? ? ? host->ops->pre_req(host, mrq, is_first_req); >> +} >> + >> +/** >> + * ? ? mmc_post_req - Post process a completed request >> + * ? ? @host: MMC host to post process command >> + * ? ? @mrq: MMC request to post process for >> + * ? ? @err: Error, if non zero, clean up any resources made in pre_req >> + * >> + * ? ? Let the host post process a completed request. Post processing of >> + * ? ? a request may be performed while another reuqest is running. >> + */ >> +static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq, >> + ? ? ? ? ? ? ? ? ? ? ? ?int err) >> +{ >> + ? ? ? if (host->ops->post_req) >> + ? ? ? ? ? ? ? host->ops->post_req(host, mrq, err); >> +} >> + >> +/** >> + * ? ? mmc_start_req - start a non-blocking request >> + * ? ? @host: MMC host to start command >> + * ? ? @areq: async request to start >> + * ? ? @error: out parameter returns 0 for success, otherwise non zero >> + * >> + * ? ? Start a new MMC custom command request for a host. >> + * ? ? If there is on ongoing async request wait for completion >> + * ? ? of that request and start the new one and return. >> + * ? ? Does not wait for the new request to complete. >> + * >> + * ? ? Returns the completed async request, NULL in case of none completed. >> + */ >> +struct mmc_async_req *mmc_start_req(struct mmc_host *host, >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct mmc_async_req *areq, int *error) >> +{ >> + ? ? ? int err = 0; >> + ? ? ? struct mmc_async_req *data = host->areq; >> + >> + ? ? ? /* Prepare a new request */ >> + ? ? ? if (areq) >> + ? ? ? ? ? ? ? mmc_pre_req(host, areq->mrq, !host->areq); >> + >> + ? ? ? if (host->areq) { >> + ? ? ? ? ? ? ? mmc_wait_for_req_done(host, host->areq->mrq); >> + ? ? ? ? ? ? ? err = host->areq->err_check(host->card, host->areq); >> + ? ? ? ? ? ? ? if (err) { >> + ? ? ? ? ? ? ? ? ? ? ? mmc_post_req(host, host->areq->mrq, 0); >> + ? ? ? ? ? ? ? ? ? ? ? if (areq) >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? mmc_post_req(host, areq->mrq, -EINVAL); >> + >> + ? ? ? ? ? ? ? ? ? ? ? host->areq = NULL; >> + ? ? ? ? ? ? ? ? ? ? ? goto out; > In this sequence, would the return value (data) have the previous areq ? > Is that intentional - doesn't seem to fit with the description. It will return the data that belongs to the completed request. The completed request will be the same as the previous request. The mmc_start_req will start a new request and return data for the completed request, if any. Do you think I should clarify the description? Regards, Per -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/