Message-ID: <ZyOujhheoeMxKxSv@lizhi-Precision-Tower-5810>
Date: Thu, 31 Oct 2024 12:21:34 -0400
From: Frank Li <Frank.li@....com>
To: Richard Zhu <hongxing.zhu@....com>
Cc: l.stach@...gutronix.de, bhelgaas@...gle.com, lpieralisi@...nel.org,
	kw@...ux.com, manivannan.sadhasivam@...aro.org, robh@...nel.org,
	krzk+dt@...nel.org, conor+dt@...nel.org, shawnguo@...nel.org,
	s.hauer@...gutronix.de, festevam@...il.com, imx@...ts.linux.dev,
	kernel@...gutronix.de, linux-pci@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 08/10] PCI: imx6: Use dwc common suspend resume method

On Thu, Oct 31, 2024 at 04:06:53PM +0800, Richard Zhu wrote:
> From: Frank Li <Frank.Li@....com>
>
> Call common dwc suspend/resume function. Use dwc common iATU method to
> send out PME_TURN_OFF message. In Old DWC implementations,
> PCIE_ATU_INHIBIT_PAYLOAD bit in iATU Ctrl2 register is reserved. So the
> generic DWC implementation of sending the PME_Turn_Off message using a
> dummy MMIO write cannot be used. Use previouse method to kick off
> PME_TURN_OFF MSG for these platforms.
>
> Replace the imx_pcie_stop_link() and imx_pcie_host_exit() by
> dw_pcie_suspend_noirq() in imx_pcie_suspend_noirq().

because dw_pcie_suspend_noirq() already do these, see below call stack:
>
> dw_pcie_suspend_noirq()
>   dw_pcie_stop_link();
>   pci->pp.ops->deinit();
>     imx_pcie_host_exit();
>
> Replace the imx_pcie_host_init(), dw_pcie_setup_rc() and
> imx_pcie_start_link() by dw_pcie_resume_noirq() in
> imx_pcie_resume_noirq().

because it dw_pcie_resume_noirq() already do these, see below call stack:

>
> dw_pcie_resume_noirq()
>   pci->pp.ops->init();
>     imx_pcie_host_init();
>   dw_pcie_setup_rc();
>   dw_pcie_start_link();
>     imx_pcie_start_link();
>
> Signed-off-by: Frank Li <Frank.Li@....com>
> Signed-off-by: Richard Zhu <hongxing.zhu@....com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 96 ++++++++++-----------------
>  1 file changed, 35 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index dbcf22e440e2..410a31e5f82a 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -33,6 +33,7 @@
>  #include <linux/pm_domain.h>
>  #include <linux/pm_runtime.h>
>
> +#include "../../pci.h"
>  #include "pcie-designware.h"
>
>  #define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
> @@ -83,6 +84,7 @@ enum imx_pcie_variants {
>  #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
>  #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP		BIT(8)
>  #define IMX_PCIE_FLAG_CLOCKS_OPTIONAL		BIT(9)
> +#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF	BIT(10)
>
>  #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
>
> @@ -107,19 +109,18 @@ struct imx_pcie_drvdata {
>  	int (*init_phy)(struct imx_pcie *pcie);
>  	int (*enable_ref_clk)(struct imx_pcie *pcie, bool enable);
>  	int (*core_reset)(struct imx_pcie *pcie, bool assert);
> +	const struct dw_pcie_host_ops *ops;
>  };
>
>  struct imx_pcie {
>  	struct dw_pcie		*pci;
>  	struct gpio_desc	*reset_gpiod;
> -	bool			link_is_up;
>  	struct clk_bulk_data	clks[IMX_PCIE_MAX_CLKS];
>  	struct regmap		*iomuxc_gpr;
>  	u16			msi_ctrl;
>  	u32			controller_id;
>  	struct reset_control	*pciephy_reset;
>  	struct reset_control	*apps_reset;
> -	struct reset_control	*turnoff_reset;
>  	u32			tx_deemph_gen1;
>  	u32			tx_deemph_gen2_3p5db;
>  	u32			tx_deemph_gen2_6db;
> @@ -898,13 +899,11 @@ static int imx_pcie_start_link(struct dw_pcie *pci)
>  		dev_info(dev, "Link: Only Gen1 is enabled\n");
>  	}
>
> -	imx_pcie->link_is_up = true;
>  	tmp = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);
>  	dev_info(dev, "Link up, Gen%i\n", tmp & PCI_EXP_LNKSTA_CLS);
>  	return 0;
>
>  err_reset_phy:
> -	imx_pcie->link_is_up = false;
>  	dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
>  		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0),
>  		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1));
> @@ -1023,9 +1022,32 @@ static u64 imx_pcie_cpu_addr_fixup(struct dw_pcie *pcie, u64 cpu_addr)
>  	return cpu_addr - entry->offset;
>  }
>
> +/*
> + * In Old DWC implementations, PCIE_ATU_INHIBIT_PAYLOAD bit in iATU Ctrl2
> + * register is reserved. So the generic DWC implementation of sending the
> + * PME_Turn_Off message using a dummy MMIO write cannot be used.
> + */
> +static void imx_pcie_pme_turn_off(struct dw_pcie_rp *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct imx_pcie *imx_pcie = to_imx_pcie(pci);
> +
> +	regmap_set_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> +	regmap_clear_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> +
> +	usleep_range(PCIE_PME_TO_L2_TIMEOUT_US/10, PCIE_PME_TO_L2_TIMEOUT_US);
> +}
> +
> +
>  static const struct dw_pcie_host_ops imx_pcie_host_ops = {
>  	.init = imx_pcie_host_init,
>  	.deinit = imx_pcie_host_exit,
> +	.pme_turn_off = imx_pcie_pme_turn_off,
> +};
> +
> +static const struct dw_pcie_host_ops imx_pcie_host_dw_pme_ops = {
> +	.init = imx_pcie_host_init,
> +	.deinit = imx_pcie_host_exit,
>  };
>
>  static const struct dw_pcie_ops dw_pcie_ops = {
> @@ -1146,43 +1168,6 @@ static int imx_add_pcie_ep(struct imx_pcie *imx_pcie,
>  	return 0;
>  }
>
> -static void imx_pcie_pm_turnoff(struct imx_pcie *imx_pcie)
> -{
> -	struct device *dev = imx_pcie->pci->dev;
> -
> -	/* Some variants have a turnoff reset in DT */
> -	if (imx_pcie->turnoff_reset) {
> -		reset_control_assert(imx_pcie->turnoff_reset);
> -		reset_control_deassert(imx_pcie->turnoff_reset);
> -		goto pm_turnoff_sleep;
> -	}
> -
> -	/* Others poke directly at IOMUXC registers */
> -	switch (imx_pcie->drvdata->variant) {
> -	case IMX6SX:
> -	case IMX6QP:
> -		regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> -				IMX6SX_GPR12_PCIE_PM_TURN_OFF,
> -				IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> -		regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> -				IMX6SX_GPR12_PCIE_PM_TURN_OFF, 0);
> -		break;
> -	default:
> -		dev_err(dev, "PME_Turn_Off not implemented\n");
> -		return;
> -	}
> -
> -	/*
> -	 * Components with an upstream port must respond to
> -	 * PME_Turn_Off with PME_TO_Ack but we can't check.
> -	 *
> -	 * The standard recommends a 1-10ms timeout after which to
> -	 * proceed anyway as if acks were received.
> -	 */
> -pm_turnoff_sleep:
> -	usleep_range(1000, 10000);
> -}
> -
>  static void imx_pcie_msi_save_restore(struct imx_pcie *imx_pcie, bool save)
>  {
>  	u8 offset;
> @@ -1206,36 +1191,26 @@ static void imx_pcie_msi_save_restore(struct imx_pcie *imx_pcie, bool save)
>  static int imx_pcie_suspend_noirq(struct device *dev)
>  {
>  	struct imx_pcie *imx_pcie = dev_get_drvdata(dev);
> -	struct dw_pcie_rp *pp = &imx_pcie->pci->pp;
>
>  	if (!(imx_pcie->drvdata->flags & IMX_PCIE_FLAG_SUPPORTS_SUSPEND))
>  		return 0;
>
>  	imx_pcie_msi_save_restore(imx_pcie, true);
> -	imx_pcie_pm_turnoff(imx_pcie);
> -	imx_pcie_stop_link(imx_pcie->pci);
> -	imx_pcie_host_exit(pp);
> -
> -	return 0;
> +	return dw_pcie_suspend_noirq(imx_pcie->pci);
>  }
>
>  static int imx_pcie_resume_noirq(struct device *dev)
>  {
>  	int ret;
>  	struct imx_pcie *imx_pcie = dev_get_drvdata(dev);
> -	struct dw_pcie_rp *pp = &imx_pcie->pci->pp;
>
>  	if (!(imx_pcie->drvdata->flags & IMX_PCIE_FLAG_SUPPORTS_SUSPEND))
>  		return 0;
>
> -	ret = imx_pcie_host_init(pp);
> +	ret = dw_pcie_resume_noirq(imx_pcie->pci);
>  	if (ret)
>  		return ret;
>  	imx_pcie_msi_save_restore(imx_pcie, false);
> -	dw_pcie_setup_rc(pp);
> -
> -	if (imx_pcie->link_is_up)
> -		imx_pcie_start_link(imx_pcie->pci);
>
>  	return 0;
>  }
> @@ -1267,11 +1242,14 @@ static int imx_pcie_probe(struct platform_device *pdev)
>
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
> -	pci->pp.ops = &imx_pcie_host_ops;
>
>  	imx_pcie->pci = pci;
>  	imx_pcie->drvdata = of_device_get_match_data(dev);
>
> +	pci->pp.ops = &imx_pcie_host_dw_pme_ops;
> +	if (imx_pcie->drvdata->ops)
> +		pci->pp.ops = imx_pcie->drvdata->ops;
> +
>  	/* Find the PHY if one is defined, only imx7d uses it */
>  	np = of_parse_phandle(node, "fsl,imx7d-pcie-phy", 0);
>  	if (np) {
> @@ -1345,13 +1323,6 @@ static int imx_pcie_probe(struct platform_device *pdev)
>  		break;
>  	}
>
> -	/* Grab turnoff reset */
> -	imx_pcie->turnoff_reset = devm_reset_control_get_optional_exclusive(dev, "turnoff");
> -	if (IS_ERR(imx_pcie->turnoff_reset)) {
> -		dev_err(dev, "Failed to get TURNOFF reset control\n");
> -		return PTR_ERR(imx_pcie->turnoff_reset);
> -	}
> -
>  	if (imx_pcie->drvdata->gpr) {
>  	/* Grab GPR config register range */
>  		imx_pcie->iomuxc_gpr =
> @@ -1430,6 +1401,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
>  		if (ret < 0)
>  			return ret;
>  	} else {
> +		pci->pp.use_atu_msg = true;
>  		ret = dw_pcie_host_init(&pci->pp);
>  		if (ret < 0)
>  			return ret;
> @@ -1494,6 +1466,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.init_phy = imx6sx_pcie_init_phy,
>  		.enable_ref_clk = imx6sx_pcie_enable_ref_clk,
>  		.core_reset = imx6sx_pcie_core_reset,
> +		.ops = &imx_pcie_host_ops,
>  	},
>  	[IMX6QP] = {
>  		.variant = IMX6QP,
> @@ -1511,6 +1484,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.init_phy = imx_pcie_init_phy,
>  		.enable_ref_clk = imx6q_pcie_enable_ref_clk,
>  		.core_reset = imx6qp_pcie_core_reset,
> +		.ops = &imx_pcie_host_ops,
>  	},
>  	[IMX7D] = {
>  		.variant = IMX7D,
> --
> 2.37.1
>

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