/**
* pci_enable_msix - configure device's MSI-X capability structure
* @dev: pointer to the pci_dev data structure of MSI-X device function
* @entries: pointer to an array of MSI-X entries
* @nvec: number of MSI-X vectors requested for allocation by device driver
*
* Setup the MSI-X capability structure of device function with the number
* of requested vectors upon its software driver call to request for
* MSI-X mode enabled on its hardware device function. A return of zero
* indicates the successful configuration of MSI-X capability structure
* with new allocated MSI-X vectors. A return of < 0 indicates a failure.
* Or a return of > 0 indicates that driver request is exceeding the number
* of vectors available. Driver should use the returned value to re-send
* its request.
**/
int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
{
int status, pos, nr_entries, free_vectors;
int i, j, temp;
u16 control;
unsigned long flags;
if (!entries || pci_msi_supported(dev) < 0)
return -EINVAL;
status = msi_init();
if (status < 0)
return status;
pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
if (!pos)
return -EINVAL;
pci_read_config_word(dev, msi_control_reg(pos), &control);
nr_entries = multi_msix_capable(control);
if (nvec > nr_entries)
return -EINVAL;
/* Check for any invalid entries */
for (i = 0; i < nvec; i++) {
if (entries[i].entry >= nr_entries)
return -EINVAL; /* invalid entry */
for (j = i + 1; j < nvec; j++) {
if (entries[i].entry == entries[j].entry)
return -EINVAL; /* duplicate entry */
}
}
temp = dev->irq;
WARN_ON(!msi_lookup_vector(dev, PCI_CAP_ID_MSIX));
/* Check whether driver already requested for MSI vector */
if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 &&
!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
printk(KERN_INFO "PCI: %s: Can't enable MSI-X. "
"Device already has an MSI vector assigned\n",
pci_name(dev));
dev->irq = temp;
return -EINVAL;
}
spin_lock_irqsave(&msi_lock, flags);
/*
* msi_lock is provided to ensure that enough vectors resources are
* available before granting.
*/
free_vectors = pci_vector_resources(last_alloc_vector,
nr_released_vectors);
/* Ensure that each MSI/MSI-X device has one vector reserved by
default to avoid any MSI-X driver to take all available
resources */
free_vectors -= nr_reserved_vectors;
spin_unlock_irqrestore(&msi_lock, flags);
if (nvec > free_vectors) {
if (free_vectors > 0)
return free_vectors;
else
return -EBUSY;
}
status = msix_capability_init(dev, entries, nvec);
return status;
}
/**
* pci_enable_msix - configure device's MSI-X capability structure
* @dev: pointer to the pci_dev data structure of MSI-X device function
* @entries: pointer to an array of MSI-X entries
* @nvec: number of MSI-X vectors requested for allocation by device driver
*
* Setup the MSI-X capability structure of device function with the number
* of requested vectors upon its software driver call to request for
* MSI-X mode enabled on its hardware device function. A return of zero
* indicates the successful configuration of MSI-X capability structure
* with new allocated MSI-X vectors. A return of < 0 indicates a failure.
* Or a return of > 0 indicates that driver request is exceeding the number
* of vectors available. Driver should use the returned value to re-send
* its request.
**/
int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
{
int status, pos, nr_entries, free_vectors;
int i, j, temp;
u16 control;
unsigned long flags;
if (!pci_msi_enable || !dev || !entries)
return -EINVAL;
if ((status = msi_init()) < 0)
return status;
if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)))
return -EINVAL;
pci_read_config_word(dev, msi_control_reg(pos), &control);
if (control & PCI_MSIX_FLAGS_ENABLE)
return -EINVAL; /* Already in MSI-X mode */
nr_entries = multi_msix_capable(control);
if (nvec > nr_entries)
return -EINVAL;
/* Check for any invalid entries */
for (i = 0; i < nvec; i++) {
if (entries[i].entry >= nr_entries)
return -EINVAL; /* invalid entry */
for (j = i + 1; j < nvec; j++) {
if (entries[i].entry == entries[j].entry)
return -EINVAL; /* duplicate entry */
}
}
temp = dev->irq;
if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
/* Lookup Sucess */
nr_entries = nvec;
/* Reroute MSI-X table */
if (reroute_msix_table(dev->irq, entries, &nr_entries)) {
/* #requested > #previous-assigned */
dev->irq = temp;
return nr_entries;
}
dev->irq = temp;
enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
return 0;
}
/* Check whether driver already requested for MSI vector */
if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 &&
!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
printk(KERN_INFO "PCI: %s: Can't enable MSI-X. "
"Device already has an MSI vector assigned\n",
pci_name(dev));
dev->irq = temp;
return -EINVAL;
}
spin_lock_irqsave(&msi_lock, flags);
/*
* msi_lock is provided to ensure that enough vectors resources are
* available before granting.
*/
free_vectors = pci_vector_resources(last_alloc_vector,
nr_released_vectors);
/* Ensure that each MSI/MSI-X device has one vector reserved by
default to avoid any MSI-X driver to take all available
resources */
free_vectors -= nr_reserved_vectors;
/* Find the average of free vectors among MSI-X devices */
if (nr_msix_devices > 0)
free_vectors /= nr_msix_devices;
spin_unlock_irqrestore(&msi_lock, flags);
if (nvec > free_vectors) {
if (free_vectors > 0)
return free_vectors;
else
return -EBUSY;
}
status = msix_capability_init(dev, entries, nvec);
if (!status && nr_msix_devices > 0)
nr_msix_devices--;
return status;
}