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Date:   Wed, 09 Dec 2020 15:46:46 +0800
From:   ziqichen@codeaurora.org
To:     Can Guo <cang@codeaurora.org>
Cc:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, rnayak@codeaurora.org,
        vinholikatti@gmail.com, jejb@linux.vnet.ibm.com,
        martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
        kernel-team@android.com, saravanak@google.com, salyzyn@google.com,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Satya Tangirala <satyat@google.com>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/1] scsi: ufs: Fix ufs power down/on specs violation
In-Reply-To: <00c4aee20f54448e93792387b598730b@codeaurora.org>
References: <1607497774-76579-1-git-send-email-ziqichen@codeaurora.org>
 <00c4aee20f54448e93792387b598730b@codeaurora.org>
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Hi Can,

On 2020-12-09 15:27, Can Guo wrote:
> On 2020-12-09 15:09, 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.
>> 
>> Power down:
>> 1. Assert RST_N low
>> 2. Turn-off REF_CLK
>> 3. Turn-off VCC
>> 4. Turn-off VCCQ/VCCQ2.
>> power on:
>> 1. Turn-on VCC
>> 2. Turn-on VCCQ/VCCQ2
>> 3. Turn-On REF_CLK
>> 4. Deassert RST_N high.
>> 
>> Signed-off-by: Ziqi Chen <ziqichen@codeaurora.org>
>> ---
>>  drivers/scsi/ufs/ufs-qcom.c | 14 ++++++++++----
>>  drivers/scsi/ufs/ufshcd.c   | 19 +++++++++----------
>>  drivers/scsi/ufs/ufshcd.h   |  4 ++--
>>  3 files changed, 21 insertions(+), 16 deletions(-)
>> 
>> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
>> index 1e434cc..5ed3a63d 100644
>> --- a/drivers/scsi/ufs/ufs-qcom.c
>> +++ b/drivers/scsi/ufs/ufs-qcom.c
>> @@ -582,6 +582,9 @@ static int ufs_qcom_suspend(struct ufs_hba *hba,
>> enum ufs_pm_op pm_op)
>>  		ufs_qcom_disable_lane_clks(host);
>>  		phy_power_off(phy);
>> 
>> +		if (hba->vops && hba->vops->device_reset)
>> +			hba->vops->device_reset(hba, false);
>> +
> 
> Instead of doing the pull-down in ufshcd_vops_suspend(), can we do
> it in ufshcd_suspend()? Since it is a common problem for all soc
> vendors.

Sure, agree, Thanks.

> 
>>  	} else if (!ufs_qcom_is_link_active(hba)) {
>>  		ufs_qcom_disable_lane_clks(host);
>>  	}
>> @@ -1400,10 +1403,11 @@ static void ufs_qcom_dump_dbg_regs(struct 
>> ufs_hba *hba)
>>  /**
>>   * ufs_qcom_device_reset() - toggle the (optional) device reset line
>>   * @hba: per-adapter instance
>> + * @toggle: need pulling up or not
>>   *
>>   * Toggles the (optional) reset line to reset the attached device.
>>   */
>> -static int ufs_qcom_device_reset(struct ufs_hba *hba)
>> +static int ufs_qcom_device_reset(struct ufs_hba *hba, bool toggle)
>>  {
>>  	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>> 
>> @@ -1416,10 +1420,12 @@ static int ufs_qcom_device_reset(struct 
>> ufs_hba *hba)
>>  	 * 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 (toggle) {
>> +		usleep_range(10, 15);
>> +		gpiod_set_value_cansleep(host->device_reset, 0);
>> +		usleep_range(10, 15);
>> +	}
>> 
>>  	return 0;
>>  }
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index 92d433d..5ab1c02 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -8633,8 +8633,6 @@ 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
>> @@ -8664,6 +8662,7 @@ static int ufshcd_suspend(struct ufs_hba *hba,
>> enum ufs_pm_op pm_op)
>> 
>>  	/* Put the host controller in low power mode if possible */
>>  	ufshcd_hba_vreg_set_lpm(hba);
>> +	ufshcd_vreg_set_lpm(hba);
> 
> Can you put ufshcd_vreg_set_lpm() before ufshcd_hba_vreg_set_lpm()?

Sure, thanks.

> 
>>  	goto out;
>> 
>>  set_link_active:
>> @@ -8729,18 +8728,18 @@ 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
>> @@ -8748,7 +8747,7 @@ 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));
>> @@ -8815,8 +8814,6 @@ 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)
>> @@ -8827,6 +8824,8 @@ 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 61344c4..47c7dab6 100644
>> --- a/drivers/scsi/ufs/ufshcd.h
>> +++ b/drivers/scsi/ufs/ufshcd.h
>> @@ -323,7 +323,7 @@ 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	(*device_reset)(struct ufs_hba *hba, bool);
>>  	void	(*config_scaling_param)(struct ufs_hba *hba,
>>  					struct devfreq_dev_profile *profile,
>>  					void *data);
>> @@ -1211,7 +1211,7 @@ static inline void
>> ufshcd_vops_dbg_register_dump(struct ufs_hba *hba)
>>  static inline void ufshcd_vops_device_reset(struct ufs_hba *hba)
>>  {
>>  	if (hba->vops && hba->vops->device_reset) {
>> -		int err = hba->vops->device_reset(hba);
>> +		int err = hba->vops->device_reset(hba, true);
>> 
>>  		if (!err)
>>  			ufshcd_set_ufs_dev_active(hba);