RE: [PATCH v9 7/8] PCI: imx6: Move the phy driver callbacks to the proper places

[Hongxing Zhu]

> -----Original Message-----
> From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Sent: 2022年6月8日 15:45
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; bhelgaas@xxxxxxxxxx;
> robh+dt@xxxxxxxxxx; broonie@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx;
> jingoohan1@xxxxxxxxx; festevam@xxxxxxxxx;
> francesco.dolcini@xxxxxxxxxxx
> Cc: linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>
> Subject: Re: [PATCH v9 7/8] PCI: imx6: Move the phy driver callbacks to the
> proper places
> 
> Am Freitag, dem 06.05.2022 um 09:47 +0800 schrieb Richard Zhu:
> > To make it more reasonable, move the phy_power_on/phy_init callbacks
> > to the proper places.
> > - move the phy_power_on() out of imx6_pcie_clk_enable().
> > - move the phy_init() out of imx6_pcie_deassert_core_reset().
> >
> > In order to save power consumption, turn off the clocks and regulators
> > when the imx6_pcie_host_init() return error.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 77
> > +++++++++++++++++++++------
> >  1 file changed, 61 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index d122c12193a6..f0ffd9011975 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -497,14 +497,6 @@ static int imx6_pcie_clk_enable(struct imx6_pcie
> *imx6_pcie)
> >  		goto err_ref_clk;
> >  	}
> >
> > -	switch (imx6_pcie->drvdata->variant) {
> > -	case IMX8MM:
> > -		if (phy_power_on(imx6_pcie->phy))
> > -			dev_err(dev, "unable to power on PHY\n");
> > -		break;
> > -	default:
> > -		break;
> > -	}
> >  	/* allow the clocks to stabilize */
> >  	usleep_range(200, 500);
> >  	return 0;
> > @@ -597,10 +589,7 @@ static int imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie)
> >  	switch (imx6_pcie->drvdata->variant) {
> >  	case IMX8MQ:
> >  		reset_control_deassert(imx6_pcie->pciephy_reset);
> > -		break;
> >  	case IMX8MM:
> > -		if (phy_init(imx6_pcie->phy))
> > -			dev_err(dev, "waiting for phy ready timeout!\n");
> 
> This looks fishy. You now fall-through from the 8MQ case to the 8MM case,
> just to break there. Please move the 8MM case down to the 6QP case that also
> doesn't need to do anything here.
> 
Thanks for your comments.
Would be changed.

> >  		break;
> >  	case IMX7D:
> >  		reset_control_deassert(imx6_pcie->pciephy_reset);
> > @@ -918,15 +907,38 @@ static int imx6_pcie_host_init(struct pcie_port
> > *pp)
> >
> >  	imx6_pcie_assert_core_reset(imx6_pcie);
> >  	imx6_pcie_init_phy(imx6_pcie);
> > +	if (imx6_pcie->phy != NULL) {
> 
> Same comment as on the last patch: drop the "!= NULL".
Okay, got that, all of them would be changed.
Thanks.

> 
> > +		ret = phy_power_on(imx6_pcie->phy);
> > +		if (ret) {
> > +			dev_err(dev, "pcie phy power up failed.\n");
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	ret = imx6_pcie_deassert_core_reset(imx6_pcie);
> >  	if (ret < 0) {
> >  		dev_err(dev, "pcie host init failed: %d.\n", ret);
> > -		return ret;
> > +		goto err_exit0;
> 
> This label is not very descriptive. Please rename to something like err_phy_off
> or something like that.
Okay. Thanks.

> 
> > +	} else if (imx6_pcie->phy != NULL) {
> 
> The else path isn't needed here. If there was an error you already moved the
> contol flow to the error label. So drop the else and again have this block under
> a simple "if (imx6_pcie->phy)" statement.
Okay. Thanks.

> 
> > +		ret = phy_init(imx6_pcie->phy);
> > +		if (ret) {
> > +			dev_err(dev, "waiting for phy ready timeout!\n");
> > +			goto err_exit1;
> 
> Again, please give those labels a more descriptive name.
> 
> All of the above comments also apply to the changes in
> imx6_pcie_resume_noirq.
Okay, thanks. Would be changed later.

Best Regards
Richard Zhu

> 
> Regards,
> Lucas
> 
> > +		}
> >  	}
> >
> >  	imx6_setup_phy_mpll(imx6_pcie);
> >
> >  	return 0;
> > +
> > +err_exit1:
> > +	imx6_pcie_clk_disable(imx6_pcie);
> > +	if (imx6_pcie->vpcie)
> > +		regulator_disable(imx6_pcie->vpcie);
> > +err_exit0:
> > +	if (imx6_pcie->phy != NULL)
> > +		phy_power_off(imx6_pcie->phy);
> > +	return ret;
> >  }
> >
> >  static const struct dw_pcie_host_ops imx6_pcie_host_ops = { @@
> > -1031,14 +1043,47 @@ static int imx6_pcie_resume_noirq(struct device
> *dev)
> >  		regulator_disable(imx6_pcie->vpcie);
> >
> >  	imx6_pcie_init_phy(imx6_pcie);
> > -	imx6_pcie_deassert_core_reset(imx6_pcie);
> > -	dw_pcie_setup_rc(pp);
> > +	if (imx6_pcie->phy != NULL) {
> > +		ret = phy_power_on(imx6_pcie->phy);
> > +		if (ret) {
> > +			dev_err(dev, "pcie phy power up failed.\n");
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	ret = imx6_pcie_deassert_core_reset(imx6_pcie);
> > +	if (ret < 0) {
> > +		dev_err(dev, "pcie deassert core reset failed: %d.\n", ret);
> > +		goto err_exit0;
> > +	} else if (imx6_pcie->phy != NULL) {
> > +		ret = phy_init(imx6_pcie->phy);
> > +		if (ret) {
> > +			dev_err(dev, "pcie phy init failed.\n");
> > +			goto err_exit1;
> > +		}
> > +	}
> >
> > +	dw_pcie_setup_rc(pp);
> >  	ret = imx6_pcie_start_link(imx6_pcie->pci);
> > -	if (ret < 0)
> > -		dev_info(dev, "pcie link is down after resume.\n");
> > +	if (ret < 0) {
> > +		/*
> > +		 * Return ret directly, since there are error exit
> > +		 * handle in imx6_pcie_start_link()
> > +		 */
> > +		dev_err(dev, "pcie link is down after resume.\n");
> > +		return ret;
> > +	}
> >
> >  	return 0;
> > +
> > +err_exit1:
> > +	imx6_pcie_clk_disable(imx6_pcie);
> > +	if (imx6_pcie->vpcie)
> > +		regulator_disable(imx6_pcie->vpcie);
> > +err_exit0:
> > +	if (imx6_pcie->phy != NULL)
> > +		phy_power_off(imx6_pcie->phy);
> > +	return ret;
> >  }
> >  #endif
> >
>