diff options
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r-- | drivers/pci/pci.c | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 427991741cf..5a14b73cf3a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -612,30 +612,51 @@ pci_enable_device_bars(struct pci_dev *dev, int bars) } /** - * pci_enable_device - Initialize device before it's used by a driver. + * __pci_enable_device - Initialize device before it's used by a driver. * @dev: PCI device to be initialized * * Initialize device before it's used by a driver. Ask low-level code * to enable I/O and memory. Wake up the device if it was suspended. * Beware, this function can fail. + * + * Note this function is a backend and is not supposed to be called by + * normal code, use pci_enable_device() instead. */ int -pci_enable_device(struct pci_dev *dev) +__pci_enable_device(struct pci_dev *dev) { int err; - if (dev->is_enabled) - return 0; - err = pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1); if (err) return err; pci_fixup_device(pci_fixup_enable, dev); - dev->is_enabled = 1; return 0; } /** + * pci_enable_device - Initialize device before it's used by a driver. + * @dev: PCI device to be initialized + * + * Initialize device before it's used by a driver. Ask low-level code + * to enable I/O and memory. Wake up the device if it was suspended. + * Beware, this function can fail. + * + * Note we don't actually enable the device many times if we call + * this function repeatedly (we just increment the count). + */ +int pci_enable_device(struct pci_dev *dev) +{ + int result; + if (atomic_add_return(1, &dev->enable_cnt) > 1) + return 0; /* already enabled */ + result = __pci_enable_device(dev); + if (result < 0) + atomic_dec(&dev->enable_cnt); + return result; +} + +/** * pcibios_disable_device - disable arch specific PCI resources for device dev * @dev: the PCI device to disable * @@ -651,12 +672,18 @@ void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {} * * Signal to the system that the PCI device is not in use by the system * anymore. This only involves disabling PCI bus-mastering, if active. + * + * Note we don't actually disable the device until all callers of + * pci_device_enable() have called pci_device_disable(). */ void pci_disable_device(struct pci_dev *dev) { u16 pci_command; + if (atomic_sub_return(1, &dev->enable_cnt) != 0) + return; + if (dev->msi_enabled) disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI), PCI_CAP_ID_MSI); @@ -672,7 +699,6 @@ pci_disable_device(struct pci_dev *dev) dev->is_busmaster = 0; pcibios_disable_device(dev); - dev->is_enabled = 0; } /** |