Re: [PATCH v5 2/7] scsi: ufs-qcom: Add reset control support for host controller

From: Vinod Koul <vkoul@kernel.org>
To: cang@codeaurora.org
Cc: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>,
	asutoshd@codeaurora.org, nguyenb@codeaurora.org,
	Rajendra Nayak <rnayak@codeaurora.org>,
	linux-scsi@vger.kernel.org, kernel-team@android.com,
	saravanak@google.com, salyzyn@google.com,
	Andy Gross <agross@kernel.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Avri Altman <avri.altman@wdc.com>,
	Pedro Sousa <pedrom.sousa@synopsys.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 2/7] scsi: ufs-qcom: Add reset control support for host controller
Date: Tue, 17 Dec 2019 09:43:42 +0530	[thread overview]
Message-ID: <20191217041342.GM2536@vkoul-mobl> (raw)
In-Reply-To: <091562cbe7d88ca1c30638bc10197074@codeaurora.org>

Hi Can,

On 17-12-19, 08:37, cang@codeaurora.org wrote:
> On 2019-12-17 03:12, Jeffrey Hugo wrote:
> > On Mon, Dec 16, 2019 at 12:05 PM Vinod Koul <vkoul@kernel.org> wrote:
> > > 
> > > Hi Can,
> > > 
> > > On 14-11-19, 22:09, Can Guo wrote:
> > > > Add reset control for host controller so that host controller can be reset
> > > > as required in its power up sequence.
> > > 
> > > I am seeing a regression on UFS on SM8150-mtp with this patch. I think
> > > Jeff is seeing same one lenove laptop on 8998.
> > 
> > Confirmed.
> > 
> > > 
> > > 845 does not seem to have this issue and only thing I can see is
> > > that on
> > > sm8150 and 8998 we define reset as:
> > > 
> > >                         resets = <&gcc GCC_UFS_BCR>;
> > >                         reset-names = "rst";
> > > 
> 
> Hi Jeffrey and Vinod,
> 
> Thanks for reporting this. May I know what kind of regression do you see on
> 8150 and 8998?
> BTW, do you have reset control for UFS PHY in your DT?
> See 71278b058a9f8752e51030e363b7a7306938f64e.
> 
> FYI, we use reset control on all of our platforms and it is
> a must during our power up sequence.

Yes we do have this and additionally both the DTS describe a 'rst' reset
and this patch tries to use this.

Can you please tell me which platform this was tested on how the reset
was described in DT

Thanks
-- 
~Vinod