[PATCH AUTOSEL 5.17 54/60] Revert "PCI: brcmstb: Add control of subdevice voltage regulators"

Sasha Levin
2022-06-07T19:19:21Z

From: Bjorn Helgaas <bhelgaas@google.com>

[ Upstream commit 212942609d83b591f5a2f2691df122d13aa3a87d ]

This reverts commit 93e41f3fca3d4a0f927b784012338c37f80a8a80.

This is part of a revert of the following commits:

11ed8b8624b8 ("PCI: brcmstb: Do not turn off WOL regulators on suspend")
93e41f3fca3d ("PCI: brcmstb: Add control of subdevice voltage regulators")
67211aadcb4b ("PCI: brcmstb: Add mechanism to turn on subdev regulators")
830aa6f29f07 ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs")

Cyril reported that 830aa6f29f07 ("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 830aa6f29f07 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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/controller/pcie-brcmstb.c | 83 ++-------------------------
1 file changed, 5 insertions(+), 78 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 3edd63735948..fd464d38fecb 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/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);
- if (!ret && !brcm_pcie_link_up(pcie))
- ret = -ENODEV;
-
- if (ret) {
- brcm_pcie_remove(pdev);
- return ret;
- }
-
- return 0;
-
+ return pci_host_probe(bridge);
fail:
__brcm_pcie_remove(pcie);
return ret;
@@ -1590,8 +1517,8 @@ static int brcm_pcie_probe(struct platform_device *pdev)
MODULE_DEVICE_TABLE(of, brcm_pcie_match);

static const struct dev_pm_ops brcm_pcie_pm_ops = {
- .suspend_noirq = brcm_pcie_suspend,
- .resume_noirq = brcm_pcie_resume,
+ .suspend = brcm_pcie_suspend,
+ .resume = brcm_pcie_resume,
};

static struct platform_driver brcm_pcie_driver = {
--
2.35.1