linux-kernel - Re: [PATCH v2 2/3] scsi: ufs: Allow resetting the UFS device

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Date:   Thu, 6 Jun 2019 00:18:28 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Avri Altman <Avri.Altman@....com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Pedro Sousa <pedrom.sousa@...opsys.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Andy Gross <agross@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Evan Green <evgreen@...omium.org>,
        "linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] scsi: ufs: Allow resetting the UFS device

On Wed 05 Jun 23:36 PDT 2019, Avri Altman wrote:

> 
> >  static int ufshcd_hba_init(struct ufs_hba *hba)
> >  {
> >  	int err;
> > @@ -7425,9 +7460,15 @@ static int ufshcd_hba_init(struct ufs_hba *hba)
> >  	if (err)
> >  		goto out_disable_vreg;
> > 
> > +	err = ufshcd_init_device_reset(hba);
> > +	if (err)
> > +		goto out_disable_variant;
> > +
> >  	hba->is_powered = true;
> >  	goto out;
> > 
> > +out_disable_variant:
> > +	ufshcd_vops_setup_regulators(hba, false);
> Is this necessary?
> ufshcd_vops_setup_regulators() was just called as part of ufshcd_variant_hba_init
> 

Yes, so my attempt here is to reverse the enablement of the vops
regulators (hence passing false). But looking at it again I see that we
should also do ufshcd_vops_exit(), so the right thing to call here is
ufshcd_variant_hba_exit().

PS. This initialization sequence should really be rewritten to first
acquire all resources and then turn them on. This mixes init/setup
sequence is really hard to reason about.

Regards,
Bjorn