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Date: Sun, 7 Jan 2024 10:46:55 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Frank Li <Frank.Li@nxp.com>
Cc: krzysztof.kozlowski@linaro.org, bhelgaas@google.com,
	conor+dt@kernel.org, devicetree@vger.kernel.org, festevam@gmail.com,
	helgaas@kernel.org, hongxing.zhu@nxp.com, imx@lists.linux.dev,
	kernel@pengutronix.de, krzysztof.kozlowski+dt@linaro.org,
	kw@linux.com, l.stach@pengutronix.de,
	linux-arm-kernel@lists.infradead.org, linux-imx@nxp.com,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	lpieralisi@kernel.org, robh@kernel.org, s.hauer@pengutronix.de,
	shawnguo@kernel.org
Subject: Re: [PATCH v7 07/16] PCI: imx6: Simplify configure_type() by using
 mode_off and mode_mask
Message-ID: <20240107051655.GF3416@thinkpad>
References: <20231227182727.1747435-1-Frank.Li@nxp.com>
 <20231227182727.1747435-8-Frank.Li@nxp.com>
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In-Reply-To: <20231227182727.1747435-8-Frank.Li@nxp.com>

On Wed, Dec 27, 2023 at 01:27:18PM -0500, Frank Li wrote:
> Add drvdata::mode_off and drvdata::mode_mask to simple

simplify

> imx6_pcie_configure_type() logic.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>

Couple of comments below.

> ---
> 
> Notes:
>     Change from v2 to v3
>     - none
>     Change from v1 to v2
>     - use ffs() to fixe build error.
> 
>  drivers/pci/controller/dwc/pci-imx6.c | 60 ++++++++++++++++++---------
>  1 file changed, 40 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 588bfb616260e..717e8fa030deb 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -68,6 +68,7 @@ enum imx6_pcie_variants {
>  
>  #define IMX6_PCIE_MAX_CLKS       6
>  
> +#define IMX6_PCIE_MAX_INSTANCES			2
>  struct imx6_pcie_drvdata {
>  	enum imx6_pcie_variants variant;
>  	enum dw_pcie_device_mode mode;
> @@ -77,6 +78,8 @@ struct imx6_pcie_drvdata {
>  	const char *clk_names[IMX6_PCIE_MAX_CLKS];
>  	const u32 ltssm_off;
>  	const u32 ltssm_mask;
> +	const u32 mode_off[IMX6_PCIE_MAX_INSTANCES];
> +	const u32 mode_mask[IMX6_PCIE_MAX_INSTANCES];
>  };
>  
>  struct imx6_pcie {
> @@ -174,32 +177,25 @@ static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie *imx6_pcie)
>  
>  static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
>  {
> -	unsigned int mask, val, mode;
> +	const struct imx6_pcie_drvdata *drvdata = imx6_pcie->drvdata;
> +	unsigned int mask, val, mode, id;
>  
> -	if (imx6_pcie->drvdata->mode == DW_PCIE_EP_TYPE)
> +	if (drvdata->mode == DW_PCIE_EP_TYPE)
>  		mode = PCI_EXP_TYPE_ENDPOINT;
>  	else
>  		mode = PCI_EXP_TYPE_ROOT_PORT;
>  
> -	switch (imx6_pcie->drvdata->variant) {
> -	case IMX8MQ:
> -	case IMX8MQ_EP:
> -		if (imx6_pcie->controller_id == 1) {
> -			mask = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE;
> -			val  = FIELD_PREP(IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
> -					  mode);
> -		} else {
> -			mask = IMX6Q_GPR12_DEVICE_TYPE;
> -			val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE, mode);
> -		}
> -		break;
> -	default:
> -		mask = IMX6Q_GPR12_DEVICE_TYPE;
> -		val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE, mode);
> -		break;
> -	}
> +	id = imx6_pcie->controller_id;
> +
> +	/* If mode_mask[id] is zero, means each controller have its individual gpr */
> +	if (!drvdata->mode_mask[id])
> +		id = 0;
> +
> +	mask = drvdata->mode_mask[id];
> +	/* FIELD_PREP mask have been constant */

No need of this comment.

> +	val = mode << (ffs(mask) - 1);
>  
> -	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);
> +	regmap_update_bits(imx6_pcie->iomuxc_gpr, drvdata->mode_off[id], mask, val);
>  }
>  
>  static int pcie_phy_poll_ack(struct imx6_pcie *imx6_pcie, bool exp_val)
> @@ -1376,6 +1372,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.clk_names = {"pcie_bus", "pcie", "pcie_phy"},
>  		.ltssm_off = IOMUXC_GPR12,
>  		.ltssm_mask = IMX6Q_GPR12_PCIE_CTL_2,
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX6SX] = {
>  		.variant = IMX6SX,
> @@ -1386,6 +1384,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.clk_names = {"pcie_bus", "pcie", "pcie_phy", "pcie_inbound_axi"},
>  		.ltssm_off = IOMUXC_GPR12,
>  		.ltssm_mask = IMX6Q_GPR12_PCIE_CTL_2,
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX6QP] = {
>  		.variant = IMX6QP,
> @@ -1397,6 +1397,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.clk_names = {"pcie_bus", "pcie", "pcie_phy"},
>  		.ltssm_off = IOMUXC_GPR12,
>  		.ltssm_mask = IMX6Q_GPR12_PCIE_CTL_2,
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX7D] = {
>  		.variant = IMX7D,
> @@ -1405,6 +1407,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
>  		.gpr = "fsl,imx7d-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_phy"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX8MQ] = {
>  		.variant = IMX8MQ,
> @@ -1412,6 +1416,10 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
>  		.gpr = "fsl,imx8mq-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
> +		.mode_off[1] = IOMUXC_GPR12,
> +		.mode_mask[1] = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,

Is the mode_mask differ between SoCs or fixed based on instances? I mean, if
there is a guarantee that it is going to be IMX6Q_GPR12_DEVICE_TYPE for instance
1 and IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE for instance 2 etc...

Then we can avoid these SoC specific config and simplify the code further.

- Mani

>  	},
>  	[IMX8MM] = {
>  		.variant = IMX8MM,
> @@ -1420,6 +1428,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  			 IMX6_PCIE_FLAG_HAS_APP_RESET,
>  		.gpr = "fsl,imx8mm-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_aux"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX8MP] = {
>  		.variant = IMX8MP,
> @@ -1428,6 +1438,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  			 IMX6_PCIE_FLAG_HAS_APP_RESET,
>  		.gpr = "fsl,imx8mp-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_aux"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX8MQ_EP] = {
>  		.variant = IMX8MQ_EP,
> @@ -1436,6 +1448,10 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.mode = DW_PCIE_EP_TYPE,
>  		.gpr = "fsl,imx8mq-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
> +		.mode_off[1] = IOMUXC_GPR12,
> +		.mode_mask[1] = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
>  	},
>  	[IMX8MM_EP] = {
>  		.variant = IMX8MM_EP,
> @@ -1443,6 +1459,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.mode = DW_PCIE_EP_TYPE,
>  		.gpr = "fsl,imx8mm-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_aux"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  	[IMX8MP_EP] = {
>  		.variant = IMX8MP_EP,
> @@ -1450,6 +1468,8 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.mode = DW_PCIE_EP_TYPE,
>  		.gpr = "fsl,imx8mp-iomuxc-gpr",
>  		.clk_names = {"pcie_bus", "pcie", "pcie_aux"},
> +		.mode_off[0] = IOMUXC_GPR12,
> +		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  	},
>  };
>  
> -- 
> 2.34.1
> 

-- 
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