Re: [PATCH v1 2/2] PCI: dw-rockchip: Add runtime PM support to Rockchip PCIe driver

[Shawn Lin <shawn.lin@rock-chips.com>]

在 2025/10/27 星期一 22:55, Anand Moon 写道:
> Add runtime power management support to the Rockchip DesignWare PCIe
> controller driver by enabling devm_pm_runtime() in the probe function.
> These changes allow the PCIe controller to suspend and resume dynamically,
> improving power efficiency on supported platforms.
> 
> Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> ---
>   drivers/pci/controller/dwc/pcie-dw-rockchip.c | 21 +++++++++++++++++++
>   1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index b878ae8e2b3e..5026598d09f8 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -20,6 +20,7 @@
>   #include <linux/of_irq.h>
>   #include <linux/phy/phy.h>
>   #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/regmap.h>
>   #include <linux/reset.h>
>   
> @@ -690,6 +691,20 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto deinit_phy;
>   
> +	ret = pm_runtime_set_suspended(dev);
> +	if (ret)
> +		goto disable_pm_runtime;
> +
> +	ret = devm_pm_runtime_enable(dev);
> +	if (ret) {
> +		ret = dev_err_probe(dev, ret, "Failed to enable runtime PM\n");
> +		goto deinit_clk;
> +	}
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret)
> +		goto disable_pm_runtime;
> +
>   	switch (data->mode) {
>   	case DW_PCIE_RC_TYPE:
>   		ret = rockchip_pcie_configure_rc(pdev, rockchip);
> @@ -709,7 +724,10 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
>   
>   	return 0;
>   
> +disable_pm_runtime:

We need to call reset_control_assert(rockchip->rst) before releasing the
the pm refcount. The problem we faced on vendor kernel is there might be 
still on-going transaction from IP to the AXI which blocks genpd to be
powered down.

> +	pm_runtime_disable(dev);
>   deinit_clk:
> +	pm_runtime_no_callbacks(dev);
>   	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
>   deinit_phy:
>   	rockchip_pcie_phy_deinit(rockchip);
> @@ -725,6 +743,9 @@ static void rockchip_pcie_remove(struct platform_device *pdev)
>   	/* Perform other cleanups as necessary */
>   	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
>   	rockchip_pcie_phy_deinit(rockchip);
> +	pm_runtime_put_sync(dev);
> +	pm_runtime_disable(dev);
> +	pm_runtime_no_callbacks(dev);
>   }
>   
>   static const struct rockchip_pcie_of_data rockchip_pcie_rc_of_data_rk3568 = {