PCI/MSI: Introduce pci_msix_table_size()
Introduce new function pci_msix_table_size() returning the size of
the MSI-X table of given PCI device or 0 if the device doesn't
support MSI-X.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index baba2eb..08aedd5 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -675,6 +675,23 @@
}
/**
+ * pci_msix_table_size - return the number of device's MSI-X table entries
+ * @dev: pointer to the pci_dev data structure of MSI-X device function
+ */
+int pci_msix_table_size(struct pci_dev *dev)
+{
+ int pos;
+ u16 control;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+ if (!pos)
+ return 0;
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ return multi_msix_capable(control);
+}
+
+/**
* 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
@@ -691,9 +708,8 @@
**/
int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
{
- int status, pos, nr_entries;
+ int status, nr_entries;
int i, j;
- u16 control;
if (!entries)
return -EINVAL;
@@ -702,9 +718,7 @@
if (status)
return status;
- pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- pci_read_config_word(dev, msi_control_reg(pos), &control);
- nr_entries = multi_msix_capable(control);
+ nr_entries = pci_msix_table_size(dev);
if (nvec > nr_entries)
return -EINVAL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7bd624b..b5d6d0e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -799,6 +799,10 @@
static inline void pci_disable_msi(struct pci_dev *dev)
{ }
+static inline int pci_msix_table_size(struct pci_dev *dev)
+{
+ return 0;
+}
static inline int pci_enable_msix(struct pci_dev *dev,
struct msix_entry *entries, int nvec)
{
@@ -823,6 +827,7 @@
extern int pci_enable_msi(struct pci_dev *dev);
extern void pci_msi_shutdown(struct pci_dev *dev);
extern void pci_disable_msi(struct pci_dev *dev);
+extern int pci_msix_table_size(struct pci_dev *dev);
extern int pci_enable_msix(struct pci_dev *dev,
struct msix_entry *entries, int nvec);
extern void pci_msix_shutdown(struct pci_dev *dev);