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Date: Tue, 22 Dec 2020 15:08:58 +0800
From: ziqichen@...eaurora.org
To: Kiwoong Kim <kwmad.kim@...sung.com>
Cc: asutoshd@...eaurora.org, nguyenb@...eaurora.org,
cang@...eaurora.org, hongwus@...eaurora.org, rnayak@...eaurora.org,
vinholikatti@...il.com, jejb@...ux.vnet.ibm.com,
martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
kernel-team@...roid.com, saravanak@...gle.com, salyzyn@...gle.com,
'Alim Akhtar' <alim.akhtar@...sung.com>,
'Avri Altman' <avri.altman@....com>,
"'James E.J. Bottomley'" <jejb@...ux.ibm.com>,
'Andy Gross' <agross@...nel.org>,
'Bjorn Andersson' <bjorn.andersson@...aro.org>,
'Matthias Brugger' <matthias.bgg@...il.com>,
'Bean Huo' <beanhuo@...ron.com>,
'Bart Van Assche' <bvanassche@....org>,
'Adrian@...eaurora.org, Hunter' <adrian.hunter@...el.com>,
'Satya Tangirala' <satyat@...gle.com>,
"'moderated list:UNIVERSAL FLASH STORAGE HOST CONTROLLER DRIVER...'"
<linux-mediatek@...ts.infradead.org>,
'open list' <linux-kernel@...r.kernel.org>,
"'open list:ARM/QUALCOMM SUPPORT'" <linux-arm-msm@...r.kernel.org>,
"'moderated list:ARM/Mediatek SoC support'"
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs
violation
On 2020-12-22 14:00, Kiwoong Kim wrote:
>> On 2020-12-22 10:04, Kiwoong Kim 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 <kwmad.kim@...sung.com>
>> >> Cc: Stanley Chu <stanley.chu@...iatek.com>
>> >> Signed-off-by: Ziqi Chen <ziqichen@...eaurora.org>
>> >> ---
>> >> 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);
>> >> + }
>> >>
>> >> 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);
>> >> + 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);
>> >
>> > Is there any point where UFS specification tells this explicitly?
>> > I think this should be moved only if the number, i.e. 10 and 15 just
>> > relies on hardware conditions.
>> >
>> >
>> > Thanks.
>> > Kiwoong Kim
>>
>> Hi Kiwoong,
>>
>> Thanks for your comment. JESD220E Line 610~611 "The UFS device shall
>> detect more than or equal to 1us of positive or negative RST_n pulse".
>> Both QCOM and Mediatek use 10~15us. What number do you think more
>> appropriate?
>>
>> Best Regards,
>> Ziqi
>
> With yours, all the SoC vendors should wait for around 10us
> unconditionally
> even if there will be a possibility that some can use shorter period.
> I see this as a sort of optimization point.
>
>
> Thanks.
> Kiwoong Kim
Got your point. As it is a controversial delay among different SoC
vendor, I'll
move it back to vops and handle it by vendor's driver.
Best Regards,
Ziqi
>>
>> >
>> >> + 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");
>> >> + } else {
>> >> + dev_err(hba->dev, "device reset pulling up failure: %d\n",
>> >> err);
>> >> }
>> >> +
>> >> 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);
>> >> 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
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