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[71.197.186.152]) by smtp.gmail.com with ESMTPSA id g12sm16231227pfm.119.2022.01.24.14.05.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Jan 2022 14:05:18 -0800 (PST) From: Kevin Hilman To: Rong Chen , Ulf Hansson , Neil Armstrong , Jerome Brunet , Martin Blumenstingl , 1131046452@qq.com, linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org Cc: 45581586@qq.com, Rong Chen Subject: Re: [PATCH] mmc: meson: Fix usage of meson_mmc_post_req() In-Reply-To: <20220106105453.3875119-1-rong.chen@amlogic.com> References: <20220106105453.3875119-1-rong.chen@amlogic.com> Date: Mon, 24 Jan 2022 14:05:17 -0800 Message-ID: <7htudsx00y.fsf@baylibre.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Rong, First, thank you finding the issue and for submitting a fix! Rong Chen writes: > To ensure the DMA moves data correctly from memory to > peripherals, DMA unmapping when the MMC request done > with calls meson_mmc_post_req(). > > Signed-off-by: Rong Chen The patch looks correct, but I think I think the changelog could be improved. If I understand the code correctly, I think what you're doing is: """ Currently meson_mmc_post_req() is called in meson_mmc_request() right after _start_cmd(). This could lead to DMA unmapping before the request is actually finished. To fix, ton't call meson_mmc_post_req() until _request_done(). """ Kevin > --- > drivers/mmc/host/meson-gx-mmc.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c > index 8f36536cb1b6..6a9554ae4b1c 100644 > --- a/drivers/mmc/host/meson-gx-mmc.c > +++ b/drivers/mmc/host/meson-gx-mmc.c > @@ -173,6 +173,7 @@ struct meson_host { > int irq; > > bool vqmmc_enabled; > + bool needs_pre_post_req; > }; > > #define CMD_CFG_LENGTH_MASK GENMASK(8, 0) > @@ -663,6 +664,8 @@ static void meson_mmc_request_done(struct mmc_host *mmc, > struct meson_host *host = mmc_priv(mmc); > > host->cmd = NULL; > + if (host->needs_pre_post_req) > + meson_mmc_post_req(mmc, mrq, 0); > mmc_request_done(host->mmc, mrq); > } > > @@ -880,7 +883,7 @@ static int meson_mmc_validate_dram_access(struct mmc_host *mmc, struct mmc_data > static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq) > { > struct meson_host *host = mmc_priv(mmc); > - bool needs_pre_post_req = mrq->data && > + host->needs_pre_post_req = mrq->data && > !(mrq->data->host_cookie & SD_EMMC_PRE_REQ_DONE); > > /* > @@ -896,22 +899,19 @@ static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq) > } > } > > - if (needs_pre_post_req) { > + if (host->needs_pre_post_req) { > meson_mmc_get_transfer_mode(mmc, mrq); > if (!meson_mmc_desc_chain_mode(mrq->data)) > - needs_pre_post_req = false; > + host->needs_pre_post_req = false; > } > > - if (needs_pre_post_req) > + if (host->needs_pre_post_req) > meson_mmc_pre_req(mmc, mrq); > > /* Stop execution */ > writel(0, host->regs + SD_EMMC_START); > > meson_mmc_start_cmd(mmc, mrq->sbc ?: mrq->cmd); > - > - if (needs_pre_post_req) > - meson_mmc_post_req(mmc, mrq, 0); > } > > static void meson_mmc_read_resp(struct mmc_host *mmc, struct mmc_command *cmd) > > base-commit: 356f3f2c5756bbb67a515760966a40fc7043cdda > -- > 2.25.1