[PATCH RFC v3 1/1] scsi: ufs: Fix ufs power down/on specs violation
Kiwoong Kim
kwmad.kim at samsung.com
Mon Dec 21 21:04:08 EST 2020
> 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
> + 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;
> }
> --
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