[PATCH v2] PCI: dw-rockchip: Add system PM support

[Diederik de Haas]

Hi,

On Fri Apr 11, 2025 at 8:14 AM CEST, Shawn Lin wrote:
> This patch adds system PM support for Rockchip platforms by adding .pme_turn_off
> and .get_ltssm hook and tries to reuse possible exist code.

s/exist/existing/ ?

> ...
>
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
> ---
>
> Changes in v2:
> - Use NOIRQ_SYSTEM_SLEEP_PM_OPS
>
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 185 +++++++++++++++++++++++---
>  1 file changed, 169 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index 56acfea..7246a49 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -21,6 +21,7 @@
>  #include <linux/regmap.h>
>  #include <linux/reset.h>
>  
> +#include "../../pci.h"
>  #include "pcie-designware.h"
>  ...
>  
> +static int rockchip_pcie_suspend(struct device *dev)
> +{
> +	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
> +	struct dw_pcie *pci = &rockchip->pci;
> +	int ret;
> +
> +	rockchip->intx = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_INTR_MASK_LEGACY);
> +
> +	ret = dw_pcie_suspend_noirq(pci);
> +	if (ret) {
> +		dev_err(dev, "failed to suspend\n");
> +		return ret;
> +	}
> +
> +	rockchip_pcie_phy_deinit(rockchip);

You're using ``rockchip_pcie_phy_deinit(rockchip)`` here ...

> +	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
> +	reset_control_assert(rockchip->rst);
> +	if (rockchip->vpcie3v3)
> +		regulator_disable(rockchip->vpcie3v3);
> +	gpiod_set_value_cansleep(rockchip->rst_gpio, 0);
> +
> +	return 0;
> +}
> +
> +static int rockchip_pcie_resume(struct device *dev)
> +{
> +	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
> +	struct dw_pcie *pci = &rockchip->pci;
> +	int ret;
> +
> +	reset_control_assert(rockchip->rst);
> +
> +	ret = clk_bulk_prepare_enable(rockchip->clk_cnt, rockchip->clks);
> +	if (ret) {
> +		dev_err(dev, "clock init failed\n");
> +		goto err_clk;
> +	}
> +
> +	if (rockchip->vpcie3v3) {
> +		ret = regulator_enable(rockchip->vpcie3v3);
> +		if (ret)
> +			goto err_power;
> +	}
> +
> +	ret = phy_init(rockchip->phy);
> +	if (ret) {
> +		dev_err(dev, "fail to init phy\n");
> +		goto err_phy_init;
> +	}
> +
> +	ret = phy_power_on(rockchip->phy);
> +	if (ret) {
> +		dev_err(dev, "fail to power on phy\n");
> +		goto err_phy_on;
> +	}

... would it be possible to reuse ``rockchip_pcie_phy_init(rockchip)``
here ?

otherwise, ``s/fail/failed/`` in the error messages

> +
> +	reset_control_deassert(rockchip->rst);
> +
> +	rockchip_pcie_writel_apb(rockchip, HIWORD_UPDATE(0xffff, rockchip->intx),
> +				 PCIE_CLIENT_INTR_MASK_LEGACY);
> +
> +	rockchip_pcie_ltssm_enable_control_mode(rockchip, PCIE_CLIENT_RC_MODE);
> +	rockchip_pcie_unmask_dll_indicator(rockchip);
> +
> +	ret = dw_pcie_resume_noirq(pci);
> +	if (ret) {
> +		dev_err(dev, "fail to resume\n");
> +		goto err_resume;
> +	}
> +
> +	return 0;
> +
> +err_resume:
> +	phy_power_off(rockchip->phy);
> +err_phy_on:
> +	phy_exit(rockchip->phy);

I initially thought this sequence was incorrect as I looked at the
``rockchip_pcie_phy_deinit`` function:

	phy_exit(rockchip->phy);
	phy_power_off(rockchip->phy);

https://elixir.bootlin.com/linux/v6.15-rc1/source/drivers/pci/controller/dwc/pcie-dw-rockchip.c#L411

But the ``phy_exit`` function docs says "Must be called after phy_power_off()."
https://elixir.bootlin.com/linux/v6.15-rc1/source/drivers/phy/phy-core.c#L264

So it seems the code/sequence in this patch is correct, but
``rockchip_pcie_phy_deinit`` has it wrong?

> +err_phy_init:
> +	if (rockchip->vpcie3v3)
> +		regulator_disable(rockchip->vpcie3v3);
> +err_power:
> +	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
> +err_clk:
> +	reset_control_deassert(rockchip->rst);
> +	return ret;
> +}
> +
>  static const struct rockchip_pcie_of_data rockchip_pcie_rc_of_data_rk3568 = {
>  	.mode = DW_PCIE_RC_TYPE,
>  };

Cheers,
  Diederik
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