[PATCH 4/6] PCI: tegra264: Power endpoint devices before enumeration

[Mikko Perttunen]

Add calls into the PCI pwrctrl framework to do required power sequencing
for endpoint devices before attempting to enumerate them, and select
PCI_PWRCTRL_GENERIC in Kconfig.

This is required for the integrated GB10B GPU on Tegra264 that requires
a power domain to be enabled before it appears on the PCI bus.

Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
---
 drivers/pci/controller/Kconfig         |  1 +
 drivers/pci/controller/pcie-tegra264.c | 22 ++++++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index d246bbe37948..ab8cb1be28ba 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -261,6 +261,7 @@ config PCIE_TEGRA264
 	tristate "NVIDIA Tegra264 PCIe controller"
 	depends on ARCH_TEGRA || COMPILE_TEST
 	select PCI_ECAM
+	select PCI_PWRCTRL_GENERIC
 	help
 	  Say Y here if you want support for the PCIe Host Controller found
 	  on NVIDIA Tegra264 SoCs.
diff --git a/drivers/pci/controller/pcie-tegra264.c b/drivers/pci/controller/pcie-tegra264.c
index c97576ab4a31..1d65ed5d0381 100644
--- a/drivers/pci/controller/pcie-tegra264.c
+++ b/drivers/pci/controller/pcie-tegra264.c
@@ -17,6 +17,7 @@
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 #include <linux/pci-ecam.h>
+#include <linux/pci-pwrctrl.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
@@ -391,6 +392,14 @@ static int tegra264_pcie_probe(struct platform_device *pdev)
 	bridge->sysdata = pcie->cfg;
 	pcie->ecam = pcie->cfg->win;
 
+	err = pci_pwrctrl_create_devices(dev);
+	if (err)
+		goto err_free_ecam;
+
+	err = pci_pwrctrl_power_on_devices(dev);
+	if (err)
+		goto err_destroy_pwrctrl;
+
 	tegra264_pcie_init(pcie);
 
 	/*
@@ -402,17 +411,23 @@ static int tegra264_pcie_probe(struct platform_device *pdev)
 				    "PCIe #%u link is down and not hotplug-capable, turning off\n",
 				    pcie->ctl_id);
 		tegra264_pcie_power_off(pcie);
-		goto err_free_ecam;
+		goto err_power_off;
 	}
 
 	err = pci_host_probe(bridge);
 	if (err < 0) {
 		dev_err_probe(dev, err, "failed to register Host Bridge\n");
-		goto err_free_ecam;
+		goto err_power_off;
 	}
 
 	return 0;
 
+err_power_off:
+	pci_pwrctrl_power_off_devices(dev);
+err_destroy_pwrctrl:
+	/* Keep devices registered so their drivers can bind before we retry. */
+	if (err != -EPROBE_DEFER)
+		pci_pwrctrl_destroy_devices(dev);
 err_free_ecam:
 	pci_ecam_free(pcie->cfg);
 err_put_pm:
@@ -437,6 +452,9 @@ static void tegra264_pcie_remove(struct platform_device *pdev)
 	pci_remove_root_bus(pcie->bridge->bus);
 	pci_unlock_rescan_remove();
 
+	pci_pwrctrl_power_off_devices(&pdev->dev);
+	pci_pwrctrl_destroy_devices(&pdev->dev);
+
 	pm_runtime_put_sync(&pdev->dev);
 	tegra_bpmp_put(pcie->bpmp);
 	pci_ecam_free(pcie->cfg);

-- 
2.55.0