linux-kernel - Re: [PATCH v5 07/10] scsi: ufs: ufs-qcom: Set initial PHY gear to max HS gear for HW ver 5 and newer

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Date:   Tue, 28 Nov 2023 19:01:27 +0800
From:   Can Guo <quic_cang@...cinc.com>
To:     Manivannan Sadhasivam <mani@...nel.org>
CC:     <bvanassche@....org>, <adrian.hunter@...el.com>,
        <beanhuo@...ron.com>, <avri.altman@....com>,
        <junwoo80.lee@...sung.com>, <martin.petersen@...cle.com>,
        <linux-scsi@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 07/10] scsi: ufs: ufs-qcom: Set initial PHY gear to max
 HS gear for HW ver 5 and newer



On 11/28/2023 6:59 PM, Manivannan Sadhasivam wrote:
> On Tue, Nov 28, 2023 at 03:58:42PM +0800, Can Guo wrote:
>> Hi Mani,
>>
>> On 11/28/2023 2:00 PM, Manivannan Sadhasivam wrote:
>>> On Thu, Nov 23, 2023 at 12:46:27AM -0800, Can Guo wrote:
>>>> Set the initial PHY gear to max HS gear for hosts with HW ver 5 and newer.
>>>>
>>>
>>> MAX_GEAR will be used for hosts with hw_ver.major >= 4
>>
>> I put it > 5 because I am not intent to touch any old targets which has
>> proven working fine with starting with PHY gear HS_G2. If I put it >= 4,
>> there would be many targets impacted by this change. I need to go back and
>> test those platforms (HW ver == 4).
>>
> 
> This assumption will make the code hard to maintain. I think if you happen to
> test it on atleast a couple of old targets it should be good since I do not see
> how others can fail.

Point taken. I will put it >= 4 in next version and test it on platforms 
like SM8350 and SM8450.

Thanks,
Can Guo.

> 
> - Mani
> 
>> Thanks,
>> Can Guo.
>>
>>>
>>>> This patch is not changing any functionalities or logic but only a
>>>> preparation patch for the next patch in this series.
>>>>
>>>> Signed-off-by: Can Guo <quic_cang@...cinc.com>
>>>> ---
>>>>    drivers/ufs/host/ufs-qcom.c | 21 +++++++++++++++------
>>>>    1 file changed, 15 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
>>>> index 6756f8d..7bbccf4 100644
>>>> --- a/drivers/ufs/host/ufs-qcom.c
>>>> +++ b/drivers/ufs/host/ufs-qcom.c
>>>> @@ -1067,6 +1067,20 @@ static void ufs_qcom_advertise_quirks(struct ufs_hba *hba)
>>>>    		hba->quirks |= UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
>>>>    }
>>>> +static void ufs_qcom_set_phy_gear(struct ufs_qcom_host *host)
>>>> +{
>>>> +	struct ufs_host_params *host_params = &host->host_params;
>>>> +
>>>> +	host->phy_gear = host_params->hs_tx_gear;
>>>> +
>>>> +	/*
>>>> +	 * Power up the PHY using the minimum supported gear (UFS_HS_G2).
>>>> +	 * Switching to max gear will be performed during reinit if supported.
>>>
>>> You need to reword this comment too.
>>>
>>>> +	 */
>>>> +	if (host->hw_ver.major < 0x5)
>>>
>>> As I mentioned above, MAX_GEAR will be used if hw_ver.major is >=4 in
>>> ufs_qcom_get_hs_gear(). So this check should be (< 0x4).
>>>
>>> - Mani
>>>
>>>> +		host->phy_gear = UFS_HS_G2;
>>>> +}
>>>> +
>>>>    static void ufs_qcom_set_host_params(struct ufs_hba *hba)
>>>>    {
>>>>    	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>>>> @@ -1303,6 +1317,7 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>>>>    	ufs_qcom_set_caps(hba);
>>>>    	ufs_qcom_advertise_quirks(hba);
>>>>    	ufs_qcom_set_host_params(hba);
>>>> +	ufs_qcom_set_phy_gear(host);
>>>>    	err = ufs_qcom_ice_init(host);
>>>>    	if (err)
>>>> @@ -1320,12 +1335,6 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>>>>    		dev_warn(dev, "%s: failed to configure the testbus %d\n",
>>>>    				__func__, err);
>>>> -	/*
>>>> -	 * Power up the PHY using the minimum supported gear (UFS_HS_G2).
>>>> -	 * Switching to max gear will be performed during reinit if supported.
>>>> -	 */
>>>> -	host->phy_gear = UFS_HS_G2;
>>>> -
>>>>    	return 0;
>>>>    out_variant_clear:
>>>> -- 
>>>> 2.7.4
>>>>
>>>
>