/**
* pci_enable_msi - configure device's MSI capability structure
* @dev: pointer to the pci_dev data structure of MSI device function
*
* Setup the MSI capability structure of device function with
* a single MSI vector upon its software driver call to request for
* MSI mode enabled on its hardware device function. A return of zero
* indicates the successful setup of an entry zero with the new MSI
* vector or non-zero for otherwise.
**/
int pci_enable_msi(struct pci_dev* dev)
{
int pos, temp, status = -EINVAL;
u16 control;
if (!pci_msi_enable || !dev)
return status;
if (dev->no_msi)
return status;
temp = dev->irq;
if ((status = msi_init()) < 0)
return status;
if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSI)))
return -EINVAL;
pci_read_config_word(dev, msi_control_reg(pos), &control);
if (control & PCI_MSI_FLAGS_ENABLE)
return 0; /* Already in MSI mode */
if (!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
/* Lookup Sucess */
unsigned long flags;
spin_lock_irqsave(&msi_lock, flags);
if (!vector_irq[dev->irq]) {
msi_desc[dev->irq]->msi_attrib.state = 0;
vector_irq[dev->irq] = -1;
nr_released_vectors--;
spin_unlock_irqrestore(&msi_lock, flags);
enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
return 0;
}
spin_unlock_irqrestore(&msi_lock, flags);
dev->irq = temp;
}
/* Check whether driver already requested for MSI-X vectors */
if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) > 0 &&
!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
printk(KERN_INFO "PCI: %s: Can't enable MSI. "
"Device already has MSI-X vectors assigned\n",
pci_name(dev));
dev->irq = temp;
return -EINVAL;
}
status = msi_capability_init(dev);
if (!status) {
if (!pos)
nr_reserved_vectors--; /* Only MSI capable */
else if (nr_msix_devices > 0)
nr_msix_devices--; /* Both MSI and MSI-X capable,
but choose enabling MSI */
}
return status;
}
/**
* pci_enable_msi - configure device's MSI capability structure
* @dev: pointer to the pci_dev data structure of MSI device function
*
* Setup the MSI capability structure of device function with
* a single MSI vector upon its software driver call to request for
* MSI mode enabled on its hardware device function. A return of zero
* indicates the successful setup of an entry zero with the new MSI
* vector or non-zero for otherwise.
**/
int pci_enable_msi(struct pci_dev* dev)
{
int pos, temp, status;
if (pci_msi_supported(dev) < 0)
return -EINVAL;
temp = dev->irq;
status = msi_init();
if (status < 0)
return status;
pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
if (!pos)
return -EINVAL;
WARN_ON(!msi_lookup_vector(dev, PCI_CAP_ID_MSI));
/* Check whether driver already requested for MSI-X vectors */
pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
if (pos > 0 && !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
printk(KERN_INFO "PCI: %s: Can't enable MSI. "
"Device already has MSI-X vectors assigned\n",
pci_name(dev));
dev->irq = temp;
return -EINVAL;
}
status = msi_capability_init(dev);
if (!status) {
if (!pos)
nr_reserved_vectors--; /* Only MSI capable */
}
return status;
}
