diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7d55039ffa05..bd993351db45 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2520,6 +2520,50 @@ int pci_resource_bar(struct pci_dev *dev, int resno, enum pci_bar_type *type) return 0; } +/** + * pci_set_vga_state - set VGA decode state on device and parents if requested + * @dev the PCI device + * @decode - true = enable decoding, false = disable decoding + * @command_bits PCI_COMMAND_IO and/or PCI_COMMAND_MEMORY + * @change_bridge - traverse ancestors and change bridges + */ +int pci_set_vga_state(struct pci_dev *dev, bool decode, + unsigned int command_bits, bool change_bridge) +{ + struct pci_bus *bus; + struct pci_dev *bridge; + u16 cmd; + + WARN_ON(command_bits & ~(PCI_COMMAND_IO|PCI_COMMAND_MEMORY)); + + pci_read_config_word(dev, PCI_COMMAND, &cmd); + if (decode == true) + cmd |= command_bits; + else + cmd &= ~command_bits; + pci_write_config_word(dev, PCI_COMMAND, cmd); + + if (change_bridge == false) + return 0; + + bus = dev->bus; + while (bus) { + bridge = bus->self; + if (bridge) { + pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, + &cmd); + if (decode == true) + cmd |= PCI_BRIDGE_CTL_VGA; + else + cmd &= ~PCI_BRIDGE_CTL_VGA; + pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, + cmd); + } + bus = bus->parent; + } + return 0; +} + #define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0}; spinlock_t resource_alignment_lock = SPIN_LOCK_UNLOCKED; |