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: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
drivers/pci/host/pci-imx6.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 071251f3..fe832e7f 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -638,8 +638,8 @@ static struct 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 pcie_port *pp = &imx6_pcie->pp;
struct device *dev = pp->dev;
@@ -674,7 +674,7 @@ static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
return 0;
}
-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 imx6_pcie *imx6_pcie;
@@ -693,10 +693,6 @@ 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);
pp->dbi_base = devm_ioremap_resource(dev, dbi_base);
if (IS_ERR(pp->dbi_base))
@@ -716,6 +712,8 @@ 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 */
@@ -828,11 +826,22 @@ 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);
--
2.9.3
