Re: [PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs violation

From: ziqichen
Date: Tue Dec 22 2020 - 02:10:13 EST

Next message: Christophe Leroy: "[PATCH] powerpc/32s: Fix RTAS machine check with VMAP stack"
Previous message: Laurent Pinchart: "Re: [PATCH 06/14] dt-bindings: display: bridge: Add i.MX8qm/qxp display pixel link binding"
In reply to: Kiwoong Kim: "RE: [PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs violation"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

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@xxxxxxxxxxx>
>> Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
>> Signed-off-by: Ziqi Chen <ziqichen@xxxxxxxxxxxxxx>
>> ---
>> 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

Next message: Christophe Leroy: "[PATCH] powerpc/32s: Fix RTAS machine check with VMAP stack"
Previous message: Laurent Pinchart: "Re: [PATCH 06/14] dt-bindings: display: bridge: Add i.MX8qm/qxp display pixel link binding"
In reply to: Kiwoong Kim: "RE: [PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs violation"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]