[PATCH 1/2] pci/of: to support explicitly declare interrupt pins unused

Zhen Lei
2016-02-25T11:56:26Z

Interrupt Pin register is read-only and optional. Some pci devices may use
msi/msix but leave the value of Interrupt Pin non-zero. In this case, the
driver will print information as below:
pci 0000:40:00.0: of_irq_parse_pci() failed with rc=-22

It's easily lead to misinterpret.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
drivers/of/of_pci_irq.c | 43 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c
index 2306313..a6d51e0 100644
--- a/drivers/of/of_pci_irq.c
+++ b/drivers/of/of_pci_irq.c
@@ -4,6 +4,38 @@
#include <linux/export.h>

/**
+ * of_irq_skip_pci - Skip the interrupt pins for a PCI device
+ * @pdev: the device whose interrupt pins may be skipped
+ * @dn: device node of pdev or pdev's ancestral bus
+ *
+ * Interrupt Pin register is read-only and optional. Some pci devices may use
+ * msi/msix but leave the value of Interrupt Pin non-zero. This function give
+ * an opportunity to suppress the warning about of_irq_parse_pci() failed.
+ */
+static int of_irq_skip_pci(const struct pci_dev *pdev,
+ const struct device_node *dn)
+{
+ const __be32 *skip_mask, *end;
+ u32 addr, mask;
+ int len;
+
+ skip_mask = of_get_property(dn, "interrupt-skip-mask", &len);
+ if (!skip_mask)
+ return 0;
+
+ end = skip_mask + (len / sizeof(__be32));
+ addr = (pdev->bus->number << 16) | (pdev->devfn << 8);
+
+ while (skip_mask < end) {
+ mask = be32_to_cpu(*(skip_mask++));
+ if ((addr & ~mask) == 0)
+ return 1;
+ }
+
+ return 0;
+}
+
+/**
* of_irq_parse_pci - Resolve the interrupt for a PCI device
* @pdev: the device whose interrupt is to be resolved
* @out_irq: structure of_irq filled by this function
@@ -30,6 +62,9 @@ int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq
rc = of_irq_parse_one(dn, 0, out_irq);
if (!rc)
return rc;
+
+ if (of_irq_skip_pci(pdev, dn))
+ return -ENODEV;
}

/* Ok, we don't, time to have fun. Let's start by building up an
@@ -89,9 +124,11 @@ int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq
laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
laddr[1] = laddr[2] = cpu_to_be32(0);
rc = of_irq_parse_raw(laddr, out_irq);
- if (rc)
- goto err;
- return 0;
+ if (!rc)
+ return 0;
+
+ if (of_irq_skip_pci(pdev, ppnode))
+ return -ENODEV;
err:
dev_err(&pdev->dev, "of_irq_parse_pci() failed with rc=%d\n", rc);
return rc;
--
2.5.0