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[104.57.184.186]) by smtp.gmail.com with ESMTPSA id s26sm3970033otd.8.2020.12.21.10.41.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Dec 2020 10:41:30 -0800 (PST) Date: Mon, 21 Dec 2020 12:41:28 -0600 From: Bjorn Andersson To: Ziqi Chen Subject: Re: [PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs violation Message-ID: References: <1608537091-78575-1-git-send-email-ziqichen@codeaurora.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1608537091-78575-1-git-send-email-ziqichen@codeaurora.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201221_134135_327450_ED961178 X-CRM114-Status: GOOD ( 35.82 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: nguyenb@codeaurora.org, cang@codeaurora.org, Alim Akhtar , vinholikatti@gmail.com, Bean Huo , Satya Tangirala , jejb@linux.vnet.ibm.com, Bart Van Assche , linux-scsi@vger.kernel.org, kwmad.kim@samsung.com, Andy Gross , kernel-team@android.com, salyzyn@google.com, "open list:ARM/QUALCOMM SUPPORT" , "James E.J. Bottomley" , Avri Altman , "moderated list:UNIVERSAL FLASH STORAGE HOST CONTROLLER DRIVER..." , Matthias Brugger , stanley.chu@mediatek.com, "moderated list:ARM/Mediatek SoC support" , rnayak@codeaurora.org, saravanak@google.com, martin.petersen@oracle.com, Adrian Hunter , open list , hongwus@codeaurora.org, asutoshd@codeaurora.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon 21 Dec 01:51 CST 2020, Ziqi Chen wrote: > As per specs, e.g, JESD220E chapter 7.2, while powering > off/on the ufs device, RST_N signal and REF_CLK signal > should be between VSS(Ground) and VCCQ/VCCQ2. > > To flexibly control device reset line, re-name the function > ufschd_vops_device_reset(sturct ufs_hba *hba) to ufshcd_ > vops_toggle_device_reset(sturct ufs_hba *hba, bool down). The > new parameter "bool down" is used to separate device reset > line pulling down from pulling up. > > Cc: Kiwoong Kim > Cc: Stanley Chu > Signed-off-by: Ziqi Chen > --- > drivers/scsi/ufs/ufs-mediatek.c | 27 +++++++++----------------- > drivers/scsi/ufs/ufs-qcom.c | 22 ++++++++++----------- > drivers/scsi/ufs/ufshcd.c | 43 ++++++++++++++++++++++++++++++----------- > drivers/scsi/ufs/ufshcd.h | 10 +++++----- > 4 files changed, 56 insertions(+), 46 deletions(-) > > diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c > index 80618af..bff2c42 100644 > --- a/drivers/scsi/ufs/ufs-mediatek.c > +++ b/drivers/scsi/ufs/ufs-mediatek.c > @@ -841,27 +841,18 @@ static int ufs_mtk_link_startup_notify(struct ufs_hba *hba, > return ret; > } > > -static int ufs_mtk_device_reset(struct ufs_hba *hba) > +static int ufs_mtk_toggle_device_reset(struct ufs_hba *hba, bool down) > { > struct arm_smccc_res res; > > - ufs_mtk_device_reset_ctrl(0, res); > - > - /* > - * The reset signal is active low. UFS devices shall detect > - * more than or equal to 1us of positive or negative RST_n > - * pulse width. > - * > - * To be on safe side, keep the reset low for at least 10us. > - */ > - usleep_range(10, 15); > - > - ufs_mtk_device_reset_ctrl(1, res); > - > - /* Some devices may need time to respond to rst_n */ > - usleep_range(10000, 15000); > + if (down) { > + ufs_mtk_device_reset_ctrl(0, res); > + } else { > + ufs_mtk_device_reset_ctrl(1, res); > > - dev_info(hba->dev, "device reset done\n"); > + /* Some devices may need time to respond to rst_n */ > + usleep_range(10000, 15000); > + } > > return 0; > } > @@ -1052,7 +1043,7 @@ static const struct ufs_hba_variant_ops ufs_hba_mtk_vops = { > .suspend = ufs_mtk_suspend, > .resume = ufs_mtk_resume, > .dbg_register_dump = ufs_mtk_dbg_register_dump, > - .device_reset = ufs_mtk_device_reset, > + .toggle_device_reset = ufs_mtk_toggle_device_reset, > .event_notify = ufs_mtk_event_notify, > }; > > diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c > index 2206b1e..c2ccaa5 100644 > --- a/drivers/scsi/ufs/ufs-qcom.c > +++ b/drivers/scsi/ufs/ufs-qcom.c > @@ -1404,12 +1404,13 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba) > } > > /** > - * ufs_qcom_device_reset() - toggle the (optional) device reset line > + * ufs_qcom_toggle_device_reset() - toggle the (optional) device reset line > * @hba: per-adapter instance > + * @down: pull down or pull up device reset line > * > * Toggles the (optional) reset line to reset the attached device. > */ > -static int ufs_qcom_device_reset(struct ufs_hba *hba) > +static int ufs_qcom_toggle_device_reset(struct ufs_hba *hba, bool down) > { > struct ufs_qcom_host *host = ufshcd_get_variant(hba); > > @@ -1417,15 +1418,12 @@ static int ufs_qcom_device_reset(struct ufs_hba *hba) > if (!host->device_reset) > return -EOPNOTSUPP; > > - /* > - * The UFS device shall detect reset pulses of 1us, sleep for 10us to > - * be on the safe side. > - */ > - gpiod_set_value_cansleep(host->device_reset, 1); > - usleep_range(10, 15); > - > - gpiod_set_value_cansleep(host->device_reset, 0); > - usleep_range(10, 15); > + if (down) { > + gpiod_set_value_cansleep(host->device_reset, 1); > + } else { > + gpiod_set_value_cansleep(host->device_reset, 0); > + usleep_range(10, 15); The comment above describes that the reset pulse should be 10uS, so the only reason I can see for the sleep here would be for devices to come back up after the reset pulse - i.e. what Mediatek believes needs 10-15mS. As such, I would like you to move this sleep out to the caller and then turns this snippet into just: gpiod_set_value_cansleep(host->device_reset, down); I don't see a problem using Mediatek's reasoning and sleep values in the common case. > + } > > return 0; > } > @@ -1473,7 +1471,7 @@ static const struct ufs_hba_variant_ops ufs_hba_qcom_vops = { > .suspend = ufs_qcom_suspend, > .resume = ufs_qcom_resume, > .dbg_register_dump = ufs_qcom_dump_dbg_regs, > - .device_reset = ufs_qcom_device_reset, > + .toggle_device_reset = ufs_qcom_toggle_device_reset, > .config_scaling_param = ufs_qcom_config_scaling_param, > .program_key = ufs_qcom_ice_program_key, > }; > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > index e221add..2ee905f 100644 > --- a/drivers/scsi/ufs/ufshcd.c > +++ b/drivers/scsi/ufs/ufshcd.c > @@ -585,7 +585,20 @@ static void ufshcd_device_reset(struct ufs_hba *hba) > { > int err; > > - err = ufshcd_vops_device_reset(hba); > + err = ufshcd_vops_toggle_device_reset(hba, true); > + if (err) { > + dev_err(hba->dev, "device reset pulling down failure: %d\n", err); "asserting device reset failed" > + return; > + } > + > + /* > + * The reset signal is active low. The UFS device > + * shall detect reset pulses of 1us, sleep for at > + * least 10us to be on the safe side. > + */ > + usleep_range(10, 15); > + > + err = ufshcd_vops_toggle_device_reset(hba, false); > > if (!err) { > ufshcd_set_ufs_dev_active(hba); > @@ -593,7 +606,11 @@ static void ufshcd_device_reset(struct ufs_hba *hba) > hba->wb_enabled = false; > hba->wb_buf_flush_enabled = false; > } > + dev_info(hba->dev, "device reset done\n"); Please use dev_dbg(), as this is only interesting to us when we're actually debugging UFS related issues. > + } else { > + dev_err(hba->dev, "device reset pulling up failure: %d\n", err); "deasserting device reset failed" > } > + > if (err != -EOPNOTSUPP) > ufshcd_update_evt_hist(hba, UFS_EVT_DEV_RESET, err); > } > @@ -8686,8 +8703,6 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) > if (ret) > goto set_dev_active; > > - ufshcd_vreg_set_lpm(hba); > - > disable_clks: > /* > * Call vendor specific suspend callback. As these callbacks may access > @@ -8703,6 +8718,9 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) > */ > ufshcd_disable_irq(hba); > > + if (ufshcd_is_link_off(hba)) > + ufshcd_vops_toggle_device_reset(hba, true); > + > ufshcd_setup_clocks(hba, false); > > if (ufshcd_is_clkgating_allowed(hba)) { > @@ -8711,6 +8729,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) > hba->clk_gating.state); > } > > + ufshcd_vreg_set_lpm(hba); > + > /* Put the host controller in low power mode if possible */ > ufshcd_hba_vreg_set_lpm(hba); > goto out; > @@ -8778,18 +8798,19 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) > old_link_state = hba->uic_link_state; > > ufshcd_hba_vreg_set_hpm(hba); > + > + ret = ufshcd_vreg_set_hpm(hba); > + if (ret) > + goto out; > + > /* Make sure clocks are enabled before accessing controller */ > ret = ufshcd_setup_clocks(hba, true); > if (ret) > - goto out; > + goto disable_vreg; > > /* enable the host irq as host controller would be active soon */ > ufshcd_enable_irq(hba); > > - ret = ufshcd_vreg_set_hpm(hba); > - if (ret) > - goto disable_irq_and_vops_clks; > - > /* > * Call vendor specific resume callback. As these callbacks may access > * vendor specific host controller register space call them when the > @@ -8797,7 +8818,7 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) > */ > ret = ufshcd_vops_resume(hba, pm_op); > if (ret) > - goto disable_vreg; > + goto disable_irq_and_vops_clks; > > /* For DeepSleep, the only supported option is to have the link off */ > WARN_ON(ufshcd_is_ufs_dev_deepsleep(hba) && !ufshcd_is_link_off(hba)); > @@ -8864,8 +8885,6 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) > ufshcd_link_state_transition(hba, old_link_state, 0); > vendor_suspend: > ufshcd_vops_suspend(hba, pm_op); > -disable_vreg: > - ufshcd_vreg_set_lpm(hba); > disable_irq_and_vops_clks: > ufshcd_disable_irq(hba); > if (hba->clk_scaling.is_allowed) > @@ -8876,6 +8895,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) > trace_ufshcd_clk_gating(dev_name(hba->dev), > hba->clk_gating.state); > } > +disable_vreg: > + ufshcd_vreg_set_lpm(hba); > out: > hba->pm_op_in_progress = 0; > if (ret) > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h > index 9bb5f0e..dccc3eb 100644 > --- a/drivers/scsi/ufs/ufshcd.h > +++ b/drivers/scsi/ufs/ufshcd.h > @@ -319,7 +319,7 @@ struct ufs_pwr_mode_info { > * @resume: called during host controller PM callback > * @dbg_register_dump: used to dump controller debug information > * @phy_initialization: used to initialize phys > - * @device_reset: called to issue a reset pulse on the UFS device > + * @toggle_device_reset: called to change logic level of reset gpio on the UFS device > * @program_key: program or evict an inline encryption key > * @event_notify: called to notify important events > */ > @@ -350,7 +350,7 @@ struct ufs_hba_variant_ops { > int (*resume)(struct ufs_hba *, enum ufs_pm_op); > void (*dbg_register_dump)(struct ufs_hba *hba); > int (*phy_initialization)(struct ufs_hba *); > - int (*device_reset)(struct ufs_hba *hba); > + int (*toggle_device_reset)(struct ufs_hba *hba, bool down); I don't think "toggle" adds any value to the understanding of what this function is expected to do, so I would prefer that you just keep it "device_reset". I also would prefer that you replace "down" with "asserted" - as this avoids questions about active high/low etc from the API. Thanks, Bjorn > void (*config_scaling_param)(struct ufs_hba *hba, > struct devfreq_dev_profile *profile, > void *data); > @@ -1216,10 +1216,10 @@ static inline void ufshcd_vops_dbg_register_dump(struct ufs_hba *hba) > hba->vops->dbg_register_dump(hba); > } > > -static inline int ufshcd_vops_device_reset(struct ufs_hba *hba) > +static inline int ufshcd_vops_toggle_device_reset(struct ufs_hba *hba, bool down) > { > - if (hba->vops && hba->vops->device_reset) > - return hba->vops->device_reset(hba); > + if (hba->vops && hba->vops->toggle_device_reset) > + return hba->vops->toggle_device_reset(hba, down); > > return -EOPNOTSUPP; > } > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel