PCI: imx6: Allow probe deferral by reset GPIO
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.
To support such designs, allow reset GPIO request to defer probing of the
driver.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Cc: yurovsky@gmail.com
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Dong Aisheng <dongas86@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c
index e0c36d6..d62ee35 100644
--- a/drivers/pci/dwc/pci-imx6.c
+++ b/drivers/pci/dwc/pci-imx6.c
@@ -595,8 +595,8 @@
.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 @@
.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 @@
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 @@
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 @@
.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 uninitialized 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);