linux-kernel - Re: [PATCH v4 7/9] PCI: dw-rockchip: Add pme_turn

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Message-ID: <aQJepFIjJx+kdBao@lizhi-Precision-Tower-5810>
Date: Wed, 29 Oct 2025 14:36:20 -0400
From: Frank Li <Frank.li@....com>
To: Sebastian Reichel <sebastian.reichel@...labora.com>
Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kwilczynski@...nel.org>,
	Manivannan Sadhasivam <mani@...nel.org>,
	Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
	Heiko Stuebner <heiko@...ech.de>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Jingoo Han <jingoohan1@...il.com>,
	Shawn Lin <shawn.lin@...k-chips.com>, linux-pci@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org,
	kernel@...labora.com
Subject: Re: [PATCH v4 7/9] PCI: dw-rockchip: Add pme_turn_off support

On Wed, Oct 29, 2025 at 06:56:46PM +0100, Sebastian Reichel wrote:
> Prepare Rockchip PCIe controller for system suspend support by
> adding the PME turn off operation.
>
> Co-developed-by: Shawn Lin <shawn.lin@...k-chips.com>
> Signed-off-by: Shawn Lin <shawn.lin@...k-chips.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> ---
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 44 +++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index ad4a907c991f..d887513a63d6 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -42,6 +42,7 @@
>  #define  PCIE_CLIENT_LD_RQ_RST_GRT	FIELD_PREP_WM16(BIT(3), 1)
>  #define  PCIE_CLIENT_ENABLE_LTSSM	FIELD_PREP_WM16(BIT(2), 1)
>  #define  PCIE_CLIENT_DISABLE_LTSSM	FIELD_PREP_WM16(BIT(2), 0)
> +#define PCIE_CLIENT_INTR_STATUS_MSG_RX	0x04
>
>  /* Interrupt Status Register Related to Legacy Interrupt */
>  #define PCIE_CLIENT_INTR_STATUS_LEGACY	0x8
> @@ -61,6 +62,11 @@
>
>  /* Interrupt Mask Register Related to Miscellaneous Operation */
>  #define PCIE_CLIENT_INTR_MASK_MISC	0x24
> +#define PCIE_CLIENT_POWER		0x2c
> +#define PCIE_CLIENT_MSG_GEN		0x34
> +#define PME_READY_ENTER_L23		BIT(3)
> +#define PME_TURN_OFF			FIELD_PREP_WM16(BIT(4), 1)
> +#define PME_TO_ACK			FIELD_PREP_WM16(BIT(9), 1)
>
>  /* Hot Reset Control Register */
>  #define PCIE_CLIENT_HOT_RESET_CTRL	0x180
> @@ -277,8 +283,46 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
>  	return 0;
>  }
>
> +static void rockchip_pcie_pme_turn_off(struct dw_pcie_rp *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
> +	struct device *dev = rockchip->pci.dev;
> +	u32 status;
> +	int ret;
> +
> +	/* 1. Broadcast PME_Turn_Off Message, bit 4 self-clear once done */
> +	rockchip_pcie_writel_apb(rockchip, PME_TURN_OFF, PCIE_CLIENT_MSG_GEN);
> +	ret = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_MSG_GEN,
> +				 status, !(status & BIT(4)), PCIE_PME_TO_L2_TIMEOUT_US / 10,
> +				 PCIE_PME_TO_L2_TIMEOUT_US);
> +	if (ret) {
> +		dev_warn(dev, "Failed to send PME_Turn_Off\n");
> +		return;
> +	}
> +
> +	/* 2. Wait for PME_TO_Ack, bit 9 will be set once received */
> +	ret = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_INTR_STATUS_MSG_RX,
> +				 status, status & BIT(9), PCIE_PME_TO_L2_TIMEOUT_US / 10,
> +				 PCIE_PME_TO_L2_TIMEOUT_US);
> +	if (ret) {
> +		dev_warn(dev, "Failed to receive PME_TO_Ack\n");
> +		return;
> +	}
> +
> +	/* 3. Clear PME_TO_Ack and Wait for ready to enter L23 message */
> +	rockchip_pcie_writel_apb(rockchip, PME_TO_ACK, PCIE_CLIENT_INTR_STATUS_MSG_RX);
> +	ret = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_POWER,
> +				 status, status & PME_READY_ENTER_L23,
> +				 PCIE_PME_TO_L2_TIMEOUT_US / 10,
> +				 PCIE_PME_TO_L2_TIMEOUT_US);
> +	if (ret)
> +		dev_err(dev, "Failed to get ready to enter L23 message\n");
> +}
> +
>  static const struct dw_pcie_host_ops rockchip_pcie_host_ops = {
>  	.init = rockchip_pcie_host_init,
> +	.pme_turn_off = rockchip_pcie_pme_turn_off,

Does common dw_pcie_pme_turn_off() work at your platform? which use iATU to
generate PME message?

I know some old chip don't support it, but I think rockchip's PCIe should
new enough.

Frank

>  };
>
>  /*
>
> --
> 2.51.0
>