[PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs violation
Kiwoong Kim
kwmad.kim at samsung.com
Tue Dec 22 01:00:43 EST 2020
> 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 at samsung.com>
> >> Cc: Stanley Chu <stanley.chu at mediatek.com>
> >> Signed-off-by: Ziqi Chen <ziqichen at codeaurora.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
>
> >
> >> + 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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