On Mon, 02 May 2022 10:38:31 +0100,
Hector Martin <marcan@xxxxxxxxx> wrote:
>
> If we're probing the PCI controller and some GPIOs are not available and
> cause a probe defer, we can end up leaving some ports initialized and
> not others and making a mess.
>
> Check for PERST# GPIOs for all ports first, and just return
> -EPROBE_DEFER if any are not ready yet, without bringing anything up.
>
> Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
> ---
> drivers/pci/controller/pcie-apple.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index e0c06c0ee731..e3aa2d461739 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -507,6 +507,20 @@ static u32 apple_pcie_rid2sid_write(struct apple_pcie_port *port,
> return readl_relaxed(port->base + PORT_RID2SID(idx));
> }
>
> +static int apple_pcie_probe_port(struct device_node *np)
> +{
> + struct gpio_desc *gd;
> +
> + gd = gpiod_get_from_of_node(np, "reset-gpios", 0,
> + GPIOD_OUT_LOW, "PERST#");
> + if (IS_ERR(gd)) {
> + return PTR_ERR(gd);
> + }
> +
> + gpiod_put(gd);
> + return 0;
> +}
> +
> static int apple_pcie_setup_port(struct apple_pcie *pcie,
> struct device_node *np)
> {
> @@ -797,8 +811,18 @@ static int apple_pcie_init(struct pci_config_window *cfg)
>
> static int apple_pcie_probe(struct platform_device *pdev)
> {
> + struct device *dev = &pdev->dev;
> + struct device_node *of_port;
> int ret;
>
> + /* Check for probe dependencies for all ports first */
> + for_each_child_of_node(dev->of_node, of_port) {
> + ret = apple_pcie_probe_port(of_port);
> + of_node_put(of_port);
> + if (ret)
> + return dev_err_probe(dev, ret, "Port %pOF probe fail\n", of_port);
> + }
> +
> ret = bus_register_notifier(&pci_bus_type, &apple_pcie_nb);
> if (ret)
> return ret;
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
M.
--
Without deviation from the norm, progress is not possible.
