Revert "PCI: brcmstb: Add control of subdevice voltage regulators"

This reverts commit 93e41f3fca.

This is part of a revert of the following commits:

  11ed8b8624 ("PCI: brcmstb: Do not turn off WOL regulators on suspend")
  93e41f3fca ("PCI: brcmstb: Add control of subdevice voltage regulators")
  67211aadcb ("PCI: brcmstb: Add mechanism to turn on subdev regulators")
  830aa6f29f ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs")

Cyril reported that 830aa6f29f ("PCI: brcmstb: Split brcm_pcie_setup()
into two funcs"), which appeared in v5.17-rc1, broke booting on the
Raspberry Pi Compute Module 4.  Apparently 830aa6f29f panics with an
Asynchronous SError Interrupt, and after further commits here is a black
screen on HDMI and no output on the serial console.

This does not seem to affect the Raspberry Pi 4 B.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=215925
Link: https://lore.kernel.org/r/20220511201856.808690-3-helgaas@kernel.org
Reported-by: Cyril Brulebois <kibi@debian.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/pcie-brcmstb.c

@@ -196,8 +196,6 @@ static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie,
 static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val);
-static int brcm_pcie_linkup(struct brcm_pcie *pcie);
-static int brcm_pcie_add_bus(struct pci_bus *bus);
 
 enum {
 	RGR1_SW_INIT_1,
@@ -331,8 +329,6 @@ struct brcm_pcie {
 	u32			hw_rev;
 	void			(*perst_set)(struct brcm_pcie *pcie, u32 val);
 	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
-	bool			refusal_mode;
-	struct subdev_regulators *sr;
 };
 
 static inline bool is_bmips(const struct brcm_pcie *pcie)
@@ -501,34 +497,6 @@ static int pci_subdev_regulators_add_bus(struct pci_bus *bus)
 	return 0;
 }
 
-static int brcm_pcie_add_bus(struct pci_bus *bus)
-{
-	struct device *dev = &bus->dev;
-	struct brcm_pcie *pcie = (struct brcm_pcie *) bus->sysdata;
-	int ret;
-
-	if (!dev->of_node || !bus->parent || !pci_is_root_bus(bus->parent))
-		return 0;
-
-	ret = pci_subdev_regulators_add_bus(bus);
-	if (ret)
-		return ret;
-
-	/* Grab the regulators for suspend/resume */
-	pcie->sr = bus->dev.driver_data;
-
-	/*
-	 * If we have failed linkup there is no point to return an error as
-	 * currently it will cause a WARNING() from pci_alloc_child_bus().
-	 * We return 0 and turn on the "refusal_mode" so that any further
-	 * accesses to the pci_dev just get 0xffffffff
-	 */
-	if (brcm_pcie_linkup(pcie) != 0)
-		pcie->refusal_mode = true;
-
-	return 0;
-}
-
 static void pci_subdev_regulators_remove_bus(struct pci_bus *bus)
 {
 	struct device *dev = &bus->dev;
@@ -857,18 +825,6 @@ static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn,
 	/* Accesses to the RC go right to the RC registers if slot==0 */
 	if (pci_is_root_bus(bus))
 		return PCI_SLOT(devfn) ? NULL : base + where;
-	if (pcie->refusal_mode) {
-		/*
-		 * At this point we do not have link.  There will be a CPU
-		 * abort -- a quirk with this controller --if Linux tries
-		 * to read any config-space registers besides those
-		 * targeting the host bridge.  To prevent this we hijack
-		 * the address to point to a safe access that will return
-		 * 0xffffffff.
-		 */
-		writel(0xffffffff, base + PCIE_MISC_RC_BAR2_CONFIG_HI);
-		return base + PCIE_MISC_RC_BAR2_CONFIG_HI + (where & 0x3);
-	}
 
 	/* For devices, write to the config space index register */
 	idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0);
@@ -897,7 +853,7 @@ static struct pci_ops brcm_pcie_ops = {
 	.map_bus = brcm_pcie_map_conf,
 	.read = pci_generic_config_read,
 	.write = pci_generic_config_write,
-	.add_bus = brcm_pcie_add_bus,
+	.add_bus = pci_subdev_regulators_add_bus,
 	.remove_bus = pci_subdev_regulators_remove_bus,
 };
 
@@ -1370,14 +1326,6 @@ static int brcm_pcie_suspend(struct device *dev)
 		return ret;
 	}
 
-	if (pcie->sr) {
-		ret = regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
-		if (ret) {
-			dev_err(dev, "Could not turn off regulators\n");
-			reset_control_reset(pcie->rescal);
-			return ret;
-		}
-	}
 	clk_disable_unprepare(pcie->clk);
 
 	return 0;
@@ -1395,17 +1343,9 @@ static int brcm_pcie_resume(struct device *dev)
 	if (ret)
 		return ret;
 
-	if (pcie->sr) {
-		ret = regulator_bulk_enable(pcie->sr->num_supplies, pcie->sr->supplies);
-		if (ret) {
-			dev_err(dev, "Could not turn on regulators\n");
-			goto err_disable_clk;
-		}
-	}
-
 	ret = reset_control_reset(pcie->rescal);
 	if (ret)
-		goto err_regulator;
+		goto err_disable_clk;
 
 	ret = brcm_phy_start(pcie);
 	if (ret)
@@ -1437,9 +1377,6 @@ static int brcm_pcie_resume(struct device *dev)
 
 err_reset:
 	reset_control_rearm(pcie->rescal);
-err_regulator:
-	if (pcie->sr)
-		regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
 err_disable_clk:
 	clk_disable_unprepare(pcie->clk);
 	return ret;
@@ -1571,17 +1508,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pcie);
 
-	ret = pci_host_probe(bridge);
+	return pci_host_probe(bridge);
-	if (!ret && !brcm_pcie_link_up(pcie))
-		ret = -ENODEV;
-
-	if (ret) {
-		brcm_pcie_remove(pdev);
-		return ret;
-	}
-
-	return 0;
-
 fail:
 	__brcm_pcie_remove(pcie);
 	return ret;
@@ -1590,8 +1517,8 @@ fail:
 MODULE_DEVICE_TABLE(of, brcm_pcie_match);
 
 static const struct dev_pm_ops brcm_pcie_pm_ops = {
-	.suspend_noirq = brcm_pcie_suspend,
+	.suspend = brcm_pcie_suspend,
-	.resume_noirq = brcm_pcie_resume,
+	.resume = brcm_pcie_resume,
 };
 
 static struct platform_driver brcm_pcie_driver = {