MSI: Export the PCI_BUS_FLAGS_NO_MSI flag in sysfs

[linux-2.6-omap-h63xx.git] / drivers / pci / pci-sysfs.c

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index fdefa7dcd15675758f31c3ce3ababd69368433d4..010e01c4bd4367d87d34f48800f50e026f97ea0d 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -131,6 +131,46 @@ is_enabled_store(struct device *dev, struct device_attribute *attr,
        return count;
 }
 
+static ssize_t
+msi_bus_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+       struct pci_dev *pdev = to_pci_dev(dev);
+
+       if (!pdev->subordinate)
+               return 0;
+
+       return sprintf (buf, "%u\n",
+                       !(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI));
+}
+
+static ssize_t
+msi_bus_store(struct device *dev, struct device_attribute *attr,
+             const char *buf, size_t count)
+{
+       struct pci_dev *pdev = to_pci_dev(dev);
+
+       /* bad things may happen if the no_msi flag is changed
+        * while some drivers are loaded */
+       if (!capable(CAP_SYS_ADMIN))
+               return count;
+
+       if (!pdev->subordinate)
+               return count;
+
+       if (*buf == '0') {
+               pdev->subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
+               dev_warn(&pdev->dev, "forced subordinate bus to not support MSI,"
+                        " bad things could happen.\n");
+       }
+
+       if (*buf == '1') {
+               pdev->subordinate->bus_flags &= ~PCI_BUS_FLAGS_NO_MSI;
+               dev_warn(&pdev->dev, "forced subordinate bus to support MSI,"
+                        " bad things could happen.\n");
+       }
+
+       return count;
+}
 
 struct device_attribute pci_dev_attrs[] = {
        __ATTR_RO(resource),
@@ -145,6 +185,7 @@ struct device_attribute pci_dev_attrs[] = {
        __ATTR(enable, 0600, is_enabled_show, is_enabled_store),
        __ATTR(broken_parity_status,(S_IRUGO|S_IWUSR),
                broken_parity_status_show,broken_parity_status_store),
+       __ATTR(msi_bus, 0644, msi_bus_show, msi_bus_store),
        __ATTR_NULL,
 };