Am Dienstag, den 21.03.2017, 06:42 -0700 schrieb Andrey Smirnov:
> Some designs implement reset GPIO via a GPIO expander connected to a
> peripheral bus. One such example would be i.MX7 Sabre board where said
> GPIO is provided by SPI shift register connected to a bitbanged SPI
> bus. In order to support such designs allow reset GPIO request to defer
> probing of the driver.
>
> Cc: yurovsky@xxxxxxxxx
> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
> Cc: Dong Aisheng <dongas86@xxxxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> ---
> drivers/pci/dwc/pci-imx6.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c
> index e0c36d6..64de9bb 100644
> --- a/drivers/pci/dwc/pci-imx6.c
> +++ b/drivers/pci/dwc/pci-imx6.c
> @@ -595,8 +595,8 @@ static struct dw_pcie_host_ops imx6_pcie_host_ops = {
> .host_init = imx6_pcie_host_init,
> };
>
> -static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
> - struct platform_device *pdev)
> +static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
> + struct platform_device *pdev)
> {
> struct dw_pcie *pci = imx6_pcie->pci;
> struct pcie_port *pp = &pci->pp;
> @@ -636,7 +636,7 @@ static const struct dw_pcie_ops dw_pcie_ops = {
> .link_up = imx6_pcie_link_up,
> };
>
> -static int __init imx6_pcie_probe(struct platform_device *pdev)
> +static int imx6_pcie_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct dw_pcie *pci;
> @@ -660,10 +660,6 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
> imx6_pcie->variant =
> (enum imx6_pcie_variants)of_device_get_match_data(dev);
>
> - /* Added for PCI abort handling */
> - hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
> - "imprecise external abort");
> -
> dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
> if (IS_ERR(pci->dbi_base))
> @@ -683,6 +679,8 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
> dev_err(dev, "unable to get reset gpio\n");
> return ret;
> }
> + } else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
> + return imx6_pcie->reset_gpio;
> }
>
> /* Fetch clocks */
> @@ -796,11 +794,22 @@ static struct platform_driver imx6_pcie_driver = {
> .name = "imx6q-pcie",
> .of_match_table = imx6_pcie_of_match,
> },
> + .probe = imx6_pcie_probe,
> .shutdown = imx6_pcie_shutdown,
> };
>
> static int __init imx6_pcie_init(void)
> {
> - return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
> + /*
> + * Since probe() can be deferred we need to make sure that
> + * hook_fault_code is not called after __init memory is freed
> + * by kernel and since imx6q_pcie_abort_handler() is a no-op
> + * we can install the handler here without risking it
> + * accessing some unitialized driver state
> + */
> + hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
> + "imprecise external abort");
> +
> + return platform_driver_register(&imx6_pcie_driver);
> }
> device_initcall(imx6_pcie_init);
