diff options
Diffstat (limited to 'drivers/pci')
-rw-r--r-- | drivers/pci/msi.c | 51 |
1 files changed, 31 insertions, 20 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index a83c1f5735d..008235947aa 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -901,6 +901,33 @@ static int msix_capability_init(struct pci_dev *dev, } /** + * pci_msi_supported - check whether MSI may be enabled on device + * @dev: pointer to the pci_dev data structure of MSI device function + * + * MSI must be globally enabled and supported by the device and its root + * bus. But, the root bus is not easy to find since some architectures + * have virtual busses on top of the PCI hierarchy (for instance the + * hypertransport bus), while the actual bus where MSI must be supported + * is below. So we test the MSI flag on all parent busses and assume + * that no quirk will ever set the NO_MSI flag on a non-root bus. + **/ +static +int pci_msi_supported(struct pci_dev * dev) +{ + struct pci_bus *bus; + + if (!pci_msi_enable || !dev || dev->no_msi) + return -EINVAL; + + /* check MSI flags of all parent busses */ + for (bus = dev->bus; bus; bus = bus->parent) + if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI) + return -EINVAL; + + return 0; +} + +/** * pci_enable_msi - configure device's MSI capability structure * @dev: pointer to the pci_dev data structure of MSI device function * @@ -912,19 +939,11 @@ static int msix_capability_init(struct pci_dev *dev, **/ int pci_enable_msi(struct pci_dev* dev) { - struct pci_bus *bus; - int pos, temp, status = -EINVAL; + int pos, temp, status; u16 control; - if (!pci_msi_enable || !dev) - return status; - - if (dev->no_msi) - return status; - - for (bus = dev->bus; bus; bus = bus->parent) - if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI) - return -EINVAL; + if (pci_msi_supported(dev) < 0) + return -EINVAL; temp = dev->irq; @@ -1134,22 +1153,14 @@ static int reroute_msix_table(int head, struct msix_entry *entries, int *nvec) **/ int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec) { - struct pci_bus *bus; int status, pos, nr_entries, free_vectors; int i, j, temp; u16 control; unsigned long flags; - if (!pci_msi_enable || !dev || !entries) + if (!entries || pci_msi_supported(dev) < 0) return -EINVAL; - if (dev->no_msi) - return -EINVAL; - - for (bus = dev->bus; bus; bus = bus->parent) - if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI) - return -EINVAL; - status = msi_init(); if (status < 0) return status; |