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Message-ID: <c6a72c38-aa63-79b8-c784-d753749f7272@quicinc.com>
Date:   Tue, 28 Nov 2023 03:40:57 +0800
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Subject: Re: [PATCH] scsi: ufs: qcom: move ufs_qcom_host_reset() to
 ufs_qcom_device_reset()
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To:     Can Guo <quic_cang@quicinc.com>,
        Manivannan Sadhasivam <mani@kernel.org>
CC:     <quic_asutoshd@quicinc.com>, <bvanassche@acm.org>,
        <beanhuo@micron.com>, <avri.altman@wdc.com>,
        <junwoo80.lee@samsung.com>, <martin.petersen@oracle.com>,
        <quic_nguyenb@quicinc.com>, <quic_nitirawa@quicinc.com>,
        <quic_rampraka@quicinc.com>, <linux-scsi@vger.kernel.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <1698145815-17396-1-git-send-email-quic_ziqichen@quicinc.com>
 <20231025074128.GA3648@thinkpad>
 <85d7a1ef-92c4-49ae-afe0-727c1b446f55@quicinc.com>
From:   Ziqi Chen <quic_ziqichen@quicinc.com>
In-Reply-To: <85d7a1ef-92c4-49ae-afe0-727c1b446f55@quicinc.com>
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On 11/22/2023 2:14 PM, Can Guo wrote:
> 
> 
> On 10/25/2023 3:41 PM, Manivannan Sadhasivam wrote:
>> On Tue, Oct 24, 2023 at 07:10:15PM +0800, Ziqi Chen wrote:
>>> During PISI test, we found the issue that host Tx still bursting after
>>
>> What is PISI test?

SI measurement.

>>
>>> H/W reset. Move ufs_qcom_host_reset() to ufs_qcom_device_reset() and
>>> reset host before device reset to stop tx burst.
>>>
>>
>> device_reset() callback is supposed to reset only the device and not 
>> the host.
>> So NACK for this patch.
> 
> Agree, the change should come in a more reasonable way.
> 
> Actually, similar code is already there in ufs_mtk_device_reset() in 
> ufs-mediatek.c, I guess here is trying to mimic that fashion.
> 
> This change, from its functionality point of view, we do need it, 
> because I occasionally (2 out of 10) hit PHY error on lane 0 during 
> reboot test (in my case, I tried SM8350, SM8450 and SM8550， all same).
> 
> [    1.911188] [DEBUG]ufshcd_update_uic_error: UECPA:0x80000002
> [    1.922843] [DEBUG]ufshcd_update_uic_error: UECDL:0x80004000
> [    1.934473] [DEBUG]ufshcd_update_uic_error: UECN:0x0
> [    1.944688] [DEBUG]ufshcd_update_uic_error: UECT:0x0
> [    1.954901] [DEBUG]ufshcd_update_uic_error: UECDME:0x0
> 
> I found out that the PHY error pops out right after UFS device gets 
> reset in the 2nd init. After having this change in place, the PA/DL 
> errors are gone.

Hi Mani,

There is another way that adding a new vops that call XXX_host_reset() 
from soc vendor driver. in this way, we can call this vops in core layer 
without the dependency of device reset.
due to we already observed such error and received many same reports 
from different OEMs, we need to fix it in some way.
if you think above way is available, I will update new patch in soon. Or 
could you give us other suggestion?

-Ziqi

> 
> Thanks,
> Can Guo.
>>
>> - Mani
>>
>>> Signed-off-by: Ziqi Chen <quic_ziqichen@quicinc.com>
>>> ---
>>>   drivers/ufs/host/ufs-qcom.c | 13 +++++++------
>>>   1 file changed, 7 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
>>> index 96cb8b5..43163d3 100644
>>> --- a/drivers/ufs/host/ufs-qcom.c
>>> +++ b/drivers/ufs/host/ufs-qcom.c
>>> @@ -445,12 +445,6 @@ static int ufs_qcom_power_up_sequence(struct 
>>> ufs_hba *hba)
>>>       struct phy *phy = host->generic_phy;
>>>       int ret;
>>> -    /* Reset UFS Host Controller and PHY */
>>> -    ret = ufs_qcom_host_reset(hba);
>>> -    if (ret)
>>> -        dev_warn(hba->dev, "%s: host reset returned %d\n",
>>> -                  __func__, ret);
>>> -
>>>       /* phy initialization - calibrate the phy */
>>>       ret = phy_init(phy);
>>>       if (ret) {
>>> @@ -1709,6 +1703,13 @@ static void ufs_qcom_dump_dbg_regs(struct 
>>> ufs_hba *hba)
>>>   static int ufs_qcom_device_reset(struct ufs_hba *hba)
>>>   {
>>>       struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>>> +    int ret = 0;
>>> +
>>> +    /* Reset UFS Host Controller and PHY */
>>> +    ret = ufs_qcom_host_reset(hba);
>>> +    if (ret)
>>> +        dev_warn(hba->dev, "%s: host reset returned %d\n",
>>> +                  __func__, ret);
>>>       /* reset gpio is optional */
>>>       if (!host->device_reset)
>>> -- 
>>> 2.7.4
>>>
>>