On some chips the PCIE and PCIE_PHY blocks are in separate power domains which can be power-gated independently. The driver needs to handle this by keeping both domain active. This is intended for imx6sx where PCIE is in DISPMIX and PCIE_PHY in it's own domain. Defining the DISPMIX domain requires a way for pcie to keep it active or it will break when displays are off. The power-domains on imx6sx are meant to look like this: power-domains = <&pd_disp>, <&pd_pci>; power-domain-names = "pcie", "pcie_phy"; Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx> --- Right now if a device has a single power domain it will be activated before probe but if it has multiple domains they need to be explicitly "attached" to and controlled. Supporting both is a bit awkward, this patch makes the distinction based on (dev->pm_domain != NULL). Maybe the PM core should make this distinction based on a flag in struct device_driver instead of number of power-domains? So by default when a device has multiple power domains they would would be activated together and this patch would be unnecessary. This is marked as "RFC" mostly because I believe it should be handled inside PM core, without driver code. Does this make sense to anyone else? This is independent of recent patches adding suspend/resume support to imx pci, but supporting suspend with multi-pd requires adding device links, not just activating pds at probe time. The device_link is marked as "STATELESS" because otherwise a warning is triggered in device_links_driver_bound. This seems to happen because the pd devices are always marked as "DL_DEV_NO_DRIVER". Maybe they should be instead always be marked as DL_DEV_DRIVER_BOUND? The imx pci driver doesn't support unbind or removal anyway so this is not handled for multi-pd either. Previously: https://lkml.org/lkml/2018/7/10/230 --- drivers/pci/controller/dwc/pci-imx6.c | 48 +++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index fc9529619469..7403918010e9 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -25,10 +25,12 @@ #include <linux/resource.h> #include <linux/signal.h> #include <linux/types.h> #include <linux/interrupt.h> #include <linux/reset.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> #include "pcie-designware.h" #define to_imx6_pcie(x) dev_get_drvdata((x)->dev) @@ -57,10 +59,15 @@ struct imx6_pcie { u32 tx_deemph_gen2_6db; u32 tx_swing_full; u32 tx_swing_low; int link_gen; struct regulator *vpcie; + + /* power domain for pcie itself (dispmix) */ + struct device *pd_pcie; + /* power domain for pcie phy */ + struct device *pd_pcie_phy; }; /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */ #define PHY_PLL_LOCK_WAIT_MAX_RETRIES 2000 #define PHY_PLL_LOCK_WAIT_USLEEP_MIN 50 @@ -805,10 +812,47 @@ static int imx6_pcie_resume_noirq(struct device *dev) static const struct dev_pm_ops imx6_pcie_pm_ops = { SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq, imx6_pcie_resume_noirq) }; +static int imx6_pcie_attach_pd(struct device *dev) +{ + struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); + struct device_link *link; + + /* Do nothing when in a single power domain */ + if (dev->pm_domain) + return 0; + + imx6_pcie->pd_pcie = dev_pm_domain_attach_by_name(dev, "pcie"); + if (IS_ERR(imx6_pcie->pd_pcie)) + return PTR_ERR(imx6_pcie->pd_pcie); + link = device_link_add(dev, imx6_pcie->pd_pcie, + DL_FLAG_STATELESS | + DL_FLAG_PM_RUNTIME | + DL_FLAG_RPM_ACTIVE); + if (IS_ERR(link)) { + dev_err(dev, "Failed to add device_link to pcie pd: %ld\n", PTR_ERR(link)); + return PTR_ERR(link); + } + + imx6_pcie->pd_pcie_phy = dev_pm_domain_attach_by_name(dev, "pcie_phy"); + if (IS_ERR(imx6_pcie->pd_pcie_phy)) + return PTR_ERR(imx6_pcie->pd_pcie_phy); + + device_link_add(dev, imx6_pcie->pd_pcie_phy, + DL_FLAG_STATELESS | + DL_FLAG_PM_RUNTIME | + DL_FLAG_RPM_ACTIVE); + if (IS_ERR(link)) { + dev_err(dev, "Failed to add device_link to pcie_phy pd: %ld\n", PTR_ERR(link)); + return PTR_ERR(link); + } + + return 0; +} + static int imx6_pcie_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct dw_pcie *pci; struct imx6_pcie *imx6_pcie; @@ -945,10 +989,14 @@ static int imx6_pcie_probe(struct platform_device *pdev) imx6_pcie->vpcie = NULL; } platform_set_drvdata(pdev, imx6_pcie); + ret = imx6_pcie_attach_pd(dev); + if (ret) + return ret; + ret = imx6_add_pcie_port(imx6_pcie, pdev); if (ret < 0) return ret; return 0; -- 2.17.1
