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Date: Tue, 13 Feb 2024 10:20:07 -0500
From: Frank Li <Frank.li@nxp.com>
To: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: bhelgaas@google.com, conor+dt@kernel.org, devicetree@vger.kernel.org,
	festevam@gmail.com, helgaas@kernel.org, hongxing.zhu@nxp.com,
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	manivannan.sadhasivam@linaro.org, robh@kernel.org,
	s.hauer@pengutronix.de, shawnguo@kernel.org
Subject: Re: [PATCH v10 03/14] PCI: imx6: Simplify reset handling by using by
 using *_FLAG_HAS_*_RESET
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References: <20240205173335.1120469-1-Frank.Li@nxp.com>
 <20240205173335.1120469-4-Frank.Li@nxp.com>
 <ZctVVjjHYVczweta@lpieralisi>
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On Tue, Feb 13, 2024 at 12:41:10PM +0100, Lorenzo Pieralisi wrote:
> On Mon, Feb 05, 2024 at 12:33:24PM -0500, Frank Li wrote:
> > Refactors the reset handling logic in the imx6 PCI driver by adding
> > IMX6_PCIE_FLAG_HAS_*_RESET bitmask define for drvdata::flags.
> > 
> > The drvdata::flags and a bitmask ensures a cleaner and more scalable
> > switch-case structure for handling reset.
> > 
> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > 
> > Notes:
> >     Change from v4 to v5:
> >     - Add Mani's Reviewed-by tag
> >     - Fixed MQ_EP's flags
> >     
> >     Chagne from v3 to v4:
> >     - none
> >     Change from v2 to v3:
> >     - add Philipp's Reviewed-by tag
> >     Change from v1 to v2:
> >     - remove condition check before reset_control_(de)assert() because it is
> >       none ops if a NULL pointer pass down.
> >     - still keep condition check at probe to help identify dts file mismatch
> >       problem.
> >     
> >     Change from v1 to v2:
> >     - remove condition check before reset_control_(de)assert() because it is
> >       none ops if a NULL pointer pass down.
> >     - still keep condition check at probe to help identify dts file mismatch
> >       problem.
> > 
> >  drivers/pci/controller/dwc/pci-imx6.c | 105 ++++++++++----------------
> >  1 file changed, 39 insertions(+), 66 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> > index 59f117f855c26..a1653b58051b7 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -61,6 +61,8 @@ enum imx6_pcie_variants {
> >  #define IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE	BIT(1)
> >  #define IMX6_PCIE_FLAG_SUPPORTS_SUSPEND		BIT(2)
> >  #define IMX6_PCIE_FLAG_HAS_PHYDRV			BIT(3)
> > +#define IMX6_PCIE_FLAG_HAS_APP_RESET		BIT(4)
> > +#define IMX6_PCIE_FLAG_HAS_PHY_RESET		BIT(5)
> >  
> >  #define imx6_check_flag(pci, val)     (pci->drvdata->flags & val)
> >  
> > @@ -661,18 +663,10 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
> >  
> >  static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> >  {
> > +	reset_control_assert(imx6_pcie->pciephy_reset);
> > +	reset_control_assert(imx6_pcie->apps_reset);
> > +
> >  	switch (imx6_pcie->drvdata->variant) {
> > -	case IMX7D:
> > -	case IMX8MQ:
> > -	case IMX8MQ_EP:
> > -		reset_control_assert(imx6_pcie->pciephy_reset);
> > -		fallthrough;
> > -	case IMX8MM:
> > -	case IMX8MM_EP:
> > -	case IMX8MP:
> > -	case IMX8MP_EP:
> > -		reset_control_assert(imx6_pcie->apps_reset);
> > -		break;
> >  	case IMX6SX:
> >  		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> >  				   IMX6SX_GPR12_PCIE_TEST_POWERDOWN,
> > @@ -693,6 +687,8 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> >  		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> >  				   IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
> >  		break;
> > +	default:
> > +		break;
> >  	}
> >  
> >  	/* Some boards don't have PCIe reset GPIO. */
> > @@ -706,14 +702,10 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> >  	struct dw_pcie *pci = imx6_pcie->pci;
> >  	struct device *dev = pci->dev;
> >  
> > +	reset_control_deassert(imx6_pcie->pciephy_reset);
> > +
> >  	switch (imx6_pcie->drvdata->variant) {
> > -	case IMX8MQ:
> > -	case IMX8MQ_EP:
> > -		reset_control_deassert(imx6_pcie->pciephy_reset);
> > -		break;
> >  	case IMX7D:
> > -		reset_control_deassert(imx6_pcie->pciephy_reset);
> > -
> >  		/* Workaround for ERR010728, failure of PCI-e PLL VCO to
> >  		 * oscillate, especially when cold.  This turns off "Duty-cycle
> >  		 * Corrector" and other mysterious undocumented things.
> > @@ -745,11 +737,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> >  
> >  		usleep_range(200, 500);
> >  		break;
> > -	case IMX6Q:		/* Nothing to do */
> > -	case IMX8MM:
> > -	case IMX8MM_EP:
> > -	case IMX8MP:
> > -	case IMX8MP_EP:
> > +	default:
> >  		break;
> >  	}
> >  
> > @@ -796,16 +784,11 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
> >  				   IMX6Q_GPR12_PCIE_CTL_2,
> >  				   IMX6Q_GPR12_PCIE_CTL_2);
> >  		break;
> > -	case IMX7D:
> > -	case IMX8MQ:
> > -	case IMX8MQ_EP:
> > -	case IMX8MM:
> > -	case IMX8MM_EP:
> > -	case IMX8MP:
> > -	case IMX8MP_EP:
> > -		reset_control_deassert(imx6_pcie->apps_reset);
> > +	default:
> >  		break;
> >  	}
> > +
> > +	reset_control_deassert(imx6_pcie->apps_reset);
> 
> You rely on the fact that passing NULL is a no-op on platforms where
> this wasn't called before (valid question for other hunks in this commit),
> correct ?
> 

Thank you take time to review it. 
Yes, it follow Philipp's suggestion. Remove conditional check at v2.

Frank

> Just checking, it does not make things much cleaner but I am not opposed to
> this change.
> 
> Thanks,
> Lorenzo
> 
> >  }
> >  
> >  static void imx6_pcie_ltssm_disable(struct device *dev)
> > @@ -819,16 +802,11 @@ static void imx6_pcie_ltssm_disable(struct device *dev)
> >  		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> >  				   IMX6Q_GPR12_PCIE_CTL_2, 0);
> >  		break;
> > -	case IMX7D:
> > -	case IMX8MQ:
> > -	case IMX8MQ_EP:
> > -	case IMX8MM:
> > -	case IMX8MM_EP:
> > -	case IMX8MP:
> > -	case IMX8MP_EP:
> > -		reset_control_assert(imx6_pcie->apps_reset);
> > +	default:
> >  		break;
> >  	}
> > +
> > +	reset_control_assert(imx6_pcie->apps_reset);
> >  }
> >  
> >  static int imx6_pcie_start_link(struct dw_pcie *pci)
> > @@ -1287,38 +1265,26 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> >  					     "failed to get pcie phy\n");
> >  	}
> >  
> > +	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_APP_RESET)) {
> > +		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev, "apps");
> > +		if (IS_ERR(imx6_pcie->apps_reset))
> > +			return dev_err_probe(dev, PTR_ERR(imx6_pcie->apps_reset),
> > +					     "failed to get pcie apps reset control\n");
> > +	}
> > +
> > +	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_PHY_RESET)) {
> > +		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev, "pciephy");
> > +		if (IS_ERR(imx6_pcie->pciephy_reset))
> > +			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pciephy_reset),
> > +					     "Failed to get PCIEPHY reset control\n");
> > +	}
> > +
> >  	switch (imx6_pcie->drvdata->variant) {
> >  	case IMX8MQ:
> >  	case IMX8MQ_EP:
> >  	case IMX7D:
> >  		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> >  			imx6_pcie->controller_id = 1;
> > -
> > -		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev,
> > -									    "pciephy");
> > -		if (IS_ERR(imx6_pcie->pciephy_reset)) {
> > -			dev_err(dev, "Failed to get PCIEPHY reset control\n");
> > -			return PTR_ERR(imx6_pcie->pciephy_reset);
> > -		}
> > -
> > -		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
> > -									 "apps");
> > -		if (IS_ERR(imx6_pcie->apps_reset)) {
> > -			dev_err(dev, "Failed to get PCIE APPS reset control\n");
> > -			return PTR_ERR(imx6_pcie->apps_reset);
> > -		}
> > -		break;
> > -	case IMX8MM:
> > -	case IMX8MM_EP:
> > -	case IMX8MP:
> > -	case IMX8MP_EP:
> > -		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
> > -									 "apps");
> > -		if (IS_ERR(imx6_pcie->apps_reset))
> > -			return dev_err_probe(dev, PTR_ERR(imx6_pcie->apps_reset),
> > -					     "failed to get pcie apps reset control\n");
> > -
> > -		break;
> >  	default:
> >  		break;
> >  	}
> > @@ -1448,13 +1414,17 @@ static const struct imx6_pcie_drvdata drvdata[] = {
> >  	},
> >  	[IMX7D] = {
> >  		.variant = IMX7D,
> > -		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
> > +		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
> > +			 IMX6_PCIE_FLAG_HAS_APP_RESET |
> > +			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
> >  		.gpr = "fsl,imx7d-iomuxc-gpr",
> >  		.clk_names = imx6q_clks,
> >  		.clks_cnt = ARRAY_SIZE(imx6q_clks),
> >  	},
> >  	[IMX8MQ] = {
> >  		.variant = IMX8MQ,
> > +		.flags = IMX6_PCIE_FLAG_HAS_APP_RESET |
> > +			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
> >  		.gpr = "fsl,imx8mq-iomuxc-gpr",
> >  		.clk_names = imx8mq_clks,
> >  		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
> > @@ -1471,13 +1441,16 @@ static const struct imx6_pcie_drvdata drvdata[] = {
> >  	[IMX8MP] = {
> >  		.variant = IMX8MP,
> >  		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
> > -			 IMX6_PCIE_FLAG_HAS_PHYDRV,
> > +			 IMX6_PCIE_FLAG_HAS_PHYDRV |
> > +			 IMX6_PCIE_FLAG_HAS_APP_RESET,
> >  		.gpr = "fsl,imx8mp-iomuxc-gpr",
> >  		.clk_names = imx8mm_clks,
> >  		.clks_cnt = ARRAY_SIZE(imx8mm_clks),
> >  	},
> >  	[IMX8MQ_EP] = {
> >  		.variant = IMX8MQ_EP,
> > +		.flags = IMX6_PCIE_FLAG_HAS_APP_RESET |
> > +			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
> >  		.mode = DW_PCIE_EP_TYPE,
> >  		.gpr = "fsl,imx8mq-iomuxc-gpr",
> >  		.clk_names = imx8mq_clks,
> > -- 
> > 2.34.1
> > 
> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel