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    Subject[PATCH v2 0/6] PCI: brcmstb: Re-submit reverted patchset
    Date
    V2  -- As v1 included the minimal code to fix a regression.  v2 does
    the same but adds some improvements suggested by Bjorn.
    -- In the unlikely but possible case that some other driver
    starts using the port driver's dev_data field, do not overwrite
    it but issue an error and return.
    -- Functions probe() and resume() do similar operations but
    did them in a different order; make this order consistent
    for both.
    -- New commit to remove forward declarations.
    -- New commit for only the PCIe config-space access "refusal mode".
    -- brcm_pcie_linkup renamed to brcm_pcie_start_link
    -- Add '_noirq' to the brcm_pcie_{suspend,resume} function names
    to match the dev_pm_ops names.
    -- Changes to commit messages:
    o Explain why we are splitting a function in two parts.
    o s/RB/Root Port/

    NOTE for Bjorn: The two commits "add mechanism .." and "add control ..."
    would probably be more clear if they were squashed. They are kept
    separate as the first one's code may someday be moved under the Port
    driver. As such, there's some churn.

    NOTE for Bjorn: There is no hurry on Broadcom's side wrt which
    release cycle/phase this patchset is applied. It goes in
    when you think it is ready.

    V1 -- Resubmission of patchset after original was reverted for a
    regression.

    A submission [1] was made to enable a PCIe root port to turn on
    regulators for downstream devices. It was accepted. Months later, a
    regression was discovered on an RPi CM4 [2]. The patchset was reverted
    [3] as the fix came too late in the release cycle. The regression in
    question is triggered only when the PCIe RC DT node has no root port
    subnode, which is a perfectly reasonsable configuration.

    The original commits are now being resubmitted with some modifications
    to fix the regression. The modifcations on the original commits are
    described below (the SHA is that of the original commit):

    [830aa6f29f07 PCI: brcmstb: Split brcm_pcie_setup() into two funcs]
    NOTE: In the originally submitted patchset, this commit introduced a
    regression that was corrected by a subsequent commit in the same
    patchset. Let's not do this again.

    @@ -1411,6 +1411,10 @@ static int brcm_pcie_probe(struct platform_device *pdev)
    if (ret)
    goto fail;

    + ret = brcm_pcie_linkup(pcie);
    + if (ret)
    + goto fail;

    [67211aadcb4b PCI: brcmstb: Add mechanism to turn on subdev regulators]
    NOTE: Not related to the regression, the regulators must be freed whenever
    the PCIe tree is dismantled:

    @@ -507,6 +507,7 @@ static void pci_subdev_regulators_remove_bus(struct pci_bus *bus)

    if (regulator_bulk_disable(sr->num_supplies, sr->supplies))
    dev_err(dev, "failed to disable regulators for downstream device\n");
    + regulator_bulk_free(sr->num_supplies, sr->supplies);
    dev->driver_data = NULL;

    [93e41f3fca3d PCI: brcmstb: Add control of subdevice voltage regulators]
    NOTE: If the PCIe RC DT node was missing a Root Port subnode, the PCIe
    link-up was skipped. This is the regression. Fix it by attempting
    link-up even if the Root Port DT subnode is missing.

    @@ -503,11 +503,10 @@ static int pci_subdev_regulators_add_bus(struct pci_bus *bus)

    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))
    + if (!bus->parent || !pci_is_root_bus(bus->parent))
    return 0;
    ret = pci_subdev_regulators_add_bus(bus);

    [1] https://lore.kernel.org/r/20220106160332.2143-1-jim2101024@gmail.com
    [2] https://bugzilla.kernel.org/show_bug.cgi?id=215925
    [3] https://lore.kernel.org/linux-pci/20220511201856.808690-1-helgaas@kernel.org/

    Jim Quinlan (6):
    PCI: brcmstb: Remove unnecessary forward declarations
    PCI: brcmstb: Split brcm_pcie_setup() into two funcs
    PCI: brcmstb: Add "refusal mode" to preclude PCIe-induced CPU aborts
    PCI: brcmstb: Add mechanism to turn on subdev regulators
    PCI: brcmstb: Add control of subdevice voltage regulators
    PCI: brcmstb: Do not turn off WOL regulators on suspend

    drivers/pci/controller/pcie-brcmstb.c | 438 +++++++++++++++++++-------
    1 file changed, 332 insertions(+), 106 deletions(-)

    base-commit: c5fe7a97f20c7f3070ac870144515c0fabc6b999
    --
    2.17.1

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