From: Can Guo <cang@codeaurora.org>
To: Stanley Chu <stanley.chu@mediatek.com>
Cc: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
hongwus@codeaurora.org, ziqichen@codeaurora.org,
rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
kernel-team@android.com, saravanak@google.com,
salyzyn@google.com, Alim Akhtar <alim.akhtar@samsung.com>,
Avri Altman <avri.altman@wdc.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Bean Huo <beanhuo@micron.com>,
Bart Van Assche <bvanassche@acm.org>,
open list <linux-kernel@vger.kernel.org>,
kuohong.wang@mediatek.com
Subject: Re: [PATCH] scsi: ufs: Don't disable core_clk_unipro if the link is active
Date: Tue, 24 Nov 2020 14:15:15 +0800 [thread overview]
Message-ID: <20ae750e562d80f964045c7c44bd94d6@codeaurora.org> (raw)
In-Reply-To: <1606195221.17338.6.camel@mtkswgap22>
Hi Stanley,
On 2020-11-24 13:20, Stanley Chu wrote:
> Hi Can,
>
> On Mon, 2020-11-23 at 21:05 -0800, Can Guo wrote:
>> If we want to disable clocks but still keep the link active, both
>> ref_clk
>> and core_clk_unipro should be skipped.
>>
>
> "core_clk_unipro" seems used by ufs-qcom only and not defined in the
> UFS
> platform binding document: ufshcd_pltfrm.txt.
Agree.
>
> Could you please add the definition first and then it would be
> reasonable to be used in common driver?
>
> Or, how about add a flag in struct ufs_clk_info indicating if this
> clock
> needs be ON to keep the link active? The flag could be set properly by
> vendor initialization functions. In this way, we can also remove the
> hard-coded "ref_clk" in __ufshcd_setup_clocks().
This seems better, I will upload next version to incorporate the idea
after it is tested.
Thanks,
Can Guo.
>
> Thanks.
> Stanley Chu
>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index a7857f6..69c2e91 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -222,7 +222,7 @@ static int ufshcd_clear_tm_cmd(struct ufs_hba
>> *hba, int tag);
>> static void ufshcd_hba_exit(struct ufs_hba *hba);
>> static int ufshcd_probe_hba(struct ufs_hba *hba, bool async);
>> static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
>> - bool skip_ref_clk);
>> + bool keep_link_active);
>> static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on);
>> static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba);
>> static inline void ufshcd_add_delay_before_dme_cmd(struct ufs_hba
>> *hba);
>> @@ -1710,7 +1710,6 @@ static void ufshcd_gate_work(struct work_struct
>> *work)
>> if (!ufshcd_is_link_active(hba))
>> ufshcd_setup_clocks(hba, false);
>> else
>> - /* If link is active, device ref_clk can't be switched off */
>> __ufshcd_setup_clocks(hba, false, true);
>>
>> /*
>> @@ -7991,7 +7990,7 @@ static int ufshcd_init_hba_vreg(struct ufs_hba
>> *hba)
>> }
>>
>> static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
>> - bool skip_ref_clk)
>> + bool keep_link_active)
>> {
>> int ret = 0;
>> struct ufs_clk_info *clki;
>> @@ -8009,7 +8008,13 @@ static int __ufshcd_setup_clocks(struct ufs_hba
>> *hba, bool on,
>>
>> list_for_each_entry(clki, head, list) {
>> if (!IS_ERR_OR_NULL(clki->clk)) {
>> - if (skip_ref_clk && !strcmp(clki->name, "ref_clk"))
>> + /*
>> + * To keep link active, ref_clk and core_clk_unipro
>> + * should be kept ON.
>> + */
>> + if (keep_link_active &&
>> + (!strcmp(clki->name, "ref_clk") ||
>> + !strcmp(clki->name, "core_clk_unipro")))
>> continue;
>>
>> clk_state_changed = on ^ clki->enabled;
>> @@ -8580,7 +8585,6 @@ static int ufshcd_suspend(struct ufs_hba *hba,
>> enum ufs_pm_op pm_op)
>> if (!ufshcd_is_link_active(hba))
>> ufshcd_setup_clocks(hba, false);
>> else
>> - /* If link is active, device ref_clk can't be switched off */
>> __ufshcd_setup_clocks(hba, false, true);
>>
>> if (ufshcd_is_clkgating_allowed(hba)) {
prev parent reply other threads:[~2020-11-24 6:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 5:05 [PATCH] scsi: ufs: Don't disable core_clk_unipro if the link is active Can Guo
2020-11-24 5:20 ` Stanley Chu
2020-11-24 6:15 ` Can Guo [this message]
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