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Subject: Re: [PATCH v4 2/3] scsi: ufs: core: Add UFS RTC support
From:   Bean Huo <beanhuo@iokpp.de>
To:     Manivannan Sadhasivam <mani@kernel.org>
Cc:     avri.altman@wdc.com, bvanassche@acm.org, alim.akhtar@samsung.com,
        jejb@linux.ibm.com, martin.petersen@oracle.com,
        quic_cang@quicinc.com, quic_asutoshd@quicinc.com,
        beanhuo@micron.com, thomas@t-8ch.de, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org, mikebi@micron.com, lporzio@micron.com
Date:   Fri, 08 Dec 2023 16:12:44 +0100
In-Reply-To: <20231208145021.GC15552@thinkpad>
References: <20231208103940.153734-1-beanhuo@iokpp.de>
         <20231208103940.153734-3-beanhuo@iokpp.de>
         <20231208145021.GC15552@thinkpad>
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On Fri, 2023-12-08 at 20:20 +0530, Manivannan Sadhasivam wrote:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 */
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0val =3D ts64.tv_sec - hba->d=
ev_info.rtc_time_baseline;
> > +
>=20
> This logic will work if the host has RTC. But if there is no RTC,
> then tv_sec
> will return time elapsed since boot. The spec clearly states that
> host should
> use absolute mode if it has RTC and relative otherwise.
>=20
> Maybe you should add a logic to detect whether RTC is present or not
> and
> override the mode in device?

Thank you for your reviews. I will incorporate the suggested changes
into the patch, addressing all comments except for the RTC mode switch.
The proposal is to perform the RTC mode switch during UFS provisioning,
not at runtime in the UFS online phase. This approach ensures that the
UFS configuration is populated based on the RTC configuration
established during provisioning. It is advisable not to change the RTC
mode after provisioning is complete. Additionally, the usage of tv_sec,
which returns time elapsed since boot, suggests that there is no issue
with utilizing the RTC in this context.

Kind regards,
Bean