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Revert "PCI: brcmstb: Add control of subdevice voltage regulators"
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This reverts commit 93e41f3.

This is part of a revert of the following commits:

  11ed8b8 ("PCI: brcmstb: Do not turn off WOL regulators on suspend")
  93e41f3 ("PCI: brcmstb: Add control of subdevice voltage regulators")
  67211aa ("PCI: brcmstb: Add mechanism to turn on subdev regulators")
  830aa6f ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs")

Cyril reported that 830aa6f ("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 830aa6f 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>
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@bjorn-helgaas
bjorn-helgaas committed May 31, 2022
1 parent 7894025 commit 2129426
Showing 1 changed file with 5 additions and 78 deletions.
83 changes: 5 additions & 78 deletions drivers/pci/controller/pcie-brcmstb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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,
};

Expand Down Expand Up @@ -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;
Expand All @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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 = {
Expand Down

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