Re: [PATCH] PCI: dwc: Check the pme_turn_off callback return value

[Frank Li <Frank.li@oss.nxp.com>]

On Wed, Nov 11, 2026 at 12:18:21PM +0800, Shawn Lin wrote:
> dw_pcie_suspend_noirq() invokes the optional host ->pme_turn_off()
> callback but ignores its result, so a platform that fails to send
> PME_Turn_Off still has the link brought down as if the handshake had
> completed.
>
> Turn the callback into an int returning function and propagate its
> error from dw_pcie_suspend_noirq(), matching how the generic
> dw_pcie_pme_turn_off() path is already handled.
>
> All existing implementations return 0 except:
>   - the Layerscape PF LUT variant, which now returns -ETIMEDOUT when
>     the PME_Turn_Off handshake does not complete instead of only
>     logging it;
>   - the Rockchip host, which now returns an error only when
>     PME_Turn_Off could not be sent at all.

I remember first version it is return int.

How do you know PME_Turn_off have not sent out at all?  I remember spec
require continue after timeout.

Frank

>  Its PME_TO_Ack and
>     L23-ready wait timeouts remain non-fatal and just log, consistent
>     with the generic path, which does not abort the suspend when an
>     endpoint fails to respond: such timeouts are an endpoint behaviour
>     and must not make the whole system suspend fail.
>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
>
>  drivers/pci/controller/dwc/pci-imx6.c         |  4 +++-
>  drivers/pci/controller/dwc/pci-layerscape.c   | 22 +++++++++++++------
>  .../pci/controller/dwc/pcie-designware-host.c |  4 +++-
>  drivers/pci/controller/dwc/pcie-designware.h  |  2 +-
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 16 ++++++++------
>  drivers/pci/controller/dwc/pcie-eswin.c       |  4 +++-
>  drivers/pci/controller/dwc/pcie-qcom.c        |  4 +++-
>  drivers/pci/controller/dwc/pcie-ultrarisc.c   |  3 ++-
>  8 files changed, 39 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 38a59795f98f..643b591c789f 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1575,7 +1575,7 @@ static void imx_pcie_host_post_init(struct dw_pcie_rp *pp)
>   * 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)
> +static int 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);
> @@ -1584,6 +1584,8 @@ static void imx_pcie_pme_turn_off(struct dw_pcie_rp *pp)
>  	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);
> +
> +	return 0;
>  }
>
>  static const struct dw_pcie_host_ops imx_pcie_host_ops = {
> diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
> index 475aea3ef58a..8bd879226971 100644
> --- a/drivers/pci/controller/dwc/pci-layerscape.c
> +++ b/drivers/pci/controller/dwc/pci-layerscape.c
> @@ -117,7 +117,7 @@ static void ls_pcie_pf_lut_writel(struct ls_pcie *pcie, u32 off, u32 val)
>  		iowrite32(val, pcie->pf_lut_base + off);
>  }
>
> -static void ls_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
> +static int ls_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  	struct ls_pcie *pcie = to_ls_pcie(pci);
> @@ -132,8 +132,12 @@ static void ls_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
>  				 val, !(val & PF_MCR_PTOMR),
>  				 PCIE_PME_TO_L2_TIMEOUT_US/10,
>  				 PCIE_PME_TO_L2_TIMEOUT_US);
> -	if (ret)
> +	if (ret) {
>  		dev_err(pcie->pci->dev, "PME_Turn_off timeout\n");
> +		return ret;
> +	}
> +
> +	return 0;
>  }
>
>  static int ls_pcie_exit_from_l2(struct dw_pcie_rp *pp)
> @@ -179,7 +183,7 @@ static int ls_pcie_host_init(struct dw_pcie_rp *pp)
>  	return 0;
>  }
>
> -static void scfg_pcie_send_turnoff_msg(struct regmap *scfg, u32 reg, u32 mask)
> +static int scfg_pcie_send_turnoff_msg(struct regmap *scfg, u32 reg, u32 mask)
>  {
>  	/* Send PME_Turn_Off message */
>  	regmap_write_bits(scfg, reg, mask, mask);
> @@ -195,14 +199,17 @@ static void scfg_pcie_send_turnoff_msg(struct regmap *scfg, u32 reg, u32 mask)
>  	 * to complete the PME_Turn_Off handshake.
>  	 */
>  	regmap_write_bits(scfg, reg, mask, 0);
> +
> +	return 0;
>  }
>
> -static void ls1021a_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
> +static int ls1021a_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  	struct ls_pcie *pcie = to_ls_pcie(pci);
>
> -	scfg_pcie_send_turnoff_msg(pcie->scfg, SCFG_PEXPMWRCR(pcie->index), PMXMTTURNOFF);
> +	return scfg_pcie_send_turnoff_msg(pcie->scfg, SCFG_PEXPMWRCR(pcie->index),
> +					  PMXMTTURNOFF);
>  }
>
>  static int scfg_pcie_exit_from_l2(struct regmap *scfg, u32 reg, u32 mask)
> @@ -222,12 +229,13 @@ static int ls1021a_pcie_exit_from_l2(struct dw_pcie_rp *pp)
>  	return scfg_pcie_exit_from_l2(pcie->scfg, SCFG_PEXSFTRSTCR, PEXSR(pcie->index));
>  }
>
> -static void ls1043a_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
> +static int ls1043a_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  	struct ls_pcie *pcie = to_ls_pcie(pci);
>
> -	scfg_pcie_send_turnoff_msg(pcie->scfg, SCFG_PEXPMECR, PEXPME(pcie->index));
> +	return scfg_pcie_send_turnoff_msg(pcie->scfg, SCFG_PEXPMECR,
> +					  PEXPME(pcie->index));
>  }
>
>  static int ls1043a_pcie_exit_from_l2(struct dw_pcie_rp *pp)
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index f531c5b51b3c..eb11556aca72 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -1249,7 +1249,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>  		return 0;
>
>  	if (pci->pp.ops->pme_turn_off) {
> -		pci->pp.ops->pme_turn_off(&pci->pp);
> +		ret = pci->pp.ops->pme_turn_off(&pci->pp);
> +		if (ret)
> +			return ret;
>  	} else {
>  		ret = dw_pcie_pme_turn_off(pci);
>  		if (ret)
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 0ece9c433229..9836ea9127bd 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -440,7 +440,7 @@ struct dw_pcie_host_ops {
>  	void (*deinit)(struct dw_pcie_rp *pp);
>  	void (*post_init)(struct dw_pcie_rp *pp);
>  	int (*msi_init)(struct dw_pcie_rp *pp);
> -	void (*pme_turn_off)(struct dw_pcie_rp *pp);
> +	int (*pme_turn_off)(struct dw_pcie_rp *pp);
>  };
>
>  struct dw_pcie_rp {
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index 525a26ee1d07..ea7ef0be1214 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -464,7 +464,7 @@ static void rockchip_pcie_host_post_init(struct dw_pcie_rp *pp)
>  	pp->bridge->broken_l1ss_resume = true;
>  }
>
> -static void rockchip_pcie_pme_turn_off(struct dw_pcie_rp *pp)
> +static int 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);
> @@ -478,18 +478,16 @@ static void rockchip_pcie_pme_turn_off(struct dw_pcie_rp *pp)
>  				 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;
> +		dev_err(dev, "Failed to send PME_Turn_Off\n");
> +		return ret;
>  	}
>
>  	/* 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) {
> +	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);
> @@ -497,8 +495,12 @@ static void rockchip_pcie_pme_turn_off(struct dw_pcie_rp *pp)
>  				 status, status & PME_READY_ENTER_L23,
>  				 PCIE_PME_TO_L2_TIMEOUT_US / 10,
>  				 PCIE_PME_TO_L2_TIMEOUT_US);
> -	if (ret)
> +	if (ret) {
>  		dev_err(dev, "Failed to get ready to enter L23 message\n");
> +		ret = 0;
> +	}
> +
> +	return ret;
>  }
>
>  static const struct dw_pcie_host_ops rockchip_pcie_host_ops = {
> diff --git a/drivers/pci/controller/dwc/pcie-eswin.c b/drivers/pci/controller/dwc/pcie-eswin.c
> index 5639666d5148..ed498601312f 100644
> --- a/drivers/pci/controller/dwc/pcie-eswin.c
> +++ b/drivers/pci/controller/dwc/pcie-eswin.c
> @@ -269,7 +269,7 @@ static void eswin_pcie_host_deinit(struct dw_pcie_rp *pp)
>  	clk_bulk_disable_unprepare(pcie->num_clks, pcie->clks);
>  }
>
> -static void eswin_pcie_pme_turn_off(struct dw_pcie_rp *pp)
> +static int eswin_pcie_pme_turn_off(struct dw_pcie_rp *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  	struct eswin_pcie *pcie = to_eswin_pcie(pci);
> @@ -281,6 +281,8 @@ static void eswin_pcie_pme_turn_off(struct dw_pcie_rp *pp)
>  	 * the skip_l23_ready has been set.
>  	 */
>  	pp->skip_l23_ready = pcie->data->skip_l23;
> +
> +	return 0;
>  }
>
>  static const struct dw_pcie_host_ops eswin_pcie_host_ops = {
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index eba1b2cb30f0..9548c6568c82 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1594,11 +1594,13 @@ static void qcom_pcie_host_post_init(struct dw_pcie_rp *pp)
>  		pcie->cfg->ops->host_post_init(pcie);
>  }
>
> -static void qcom_pcie_host_pme_turn_off(struct dw_pcie_rp *pp)
> +static int qcom_pcie_host_pme_turn_off(struct dw_pcie_rp *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>
>  	writel(ELBI_SYS_CTRL_PME_TURNOFF_MSG, pci->elbi_base + ELBI_SYS_CTRL);
> +
> +	return 0;
>  }
>
>  static const struct dw_pcie_host_ops qcom_pcie_dw_ops = {
> diff --git a/drivers/pci/controller/dwc/pcie-ultrarisc.c b/drivers/pci/controller/dwc/pcie-ultrarisc.c
> index ee844ff7ed55..493b6c68b42f 100644
> --- a/drivers/pci/controller/dwc/pcie-ultrarisc.c
> +++ b/drivers/pci/controller/dwc/pcie-ultrarisc.c
> @@ -77,12 +77,13 @@ static int ultrarisc_pcie_host_init(struct dw_pcie_rp *pp)
>  	return 0;
>  }
>
> -static void ultrarisc_pcie_pme_turn_off(struct dw_pcie_rp *pp)
> +static int ultrarisc_pcie_pme_turn_off(struct dw_pcie_rp *pp)
>  {
>  	/*
>  	 * DP1000 does not support sending PME_Turn_Off from the RC.
>  	 * Keep this callback empty to skip the generic MSG TLP path.
>  	 */
> +	return 0;
>  }
>
>  static const struct dw_pcie_host_ops ultrarisc_pcie_host_ops = {
> --
> 2.25.1
>
>