[PATCH] MSI: MSI/MSI-X API updates

Second half of MSI rewrite: fix the API and update documentation.  Split
enabling MSI and MSI-X to separate pci_enable_msi()/pci_disable_msi() and
pci_enable_msix()/pci_disable_msix() functions.  free_irq() no longer has
the side effect of freeing interrupt vectors (so a device driver can do
multiple request_irq()/free_irq() cycles on the same MSI/MSI_X vector).

From: Tom L. Nguyen <tom.l.nguyen@intel.com>
Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/pci/msi.h

@@ -140,7 +140,8 @@ struct msi_desc {
 	struct {
 		__u8	type	: 5; 	/* {0: unused, 5h:MSI, 11h:MSI-X} */
 		__u8	maskbit	: 1; 	/* mask-pending bit supported ?   */
-		__u8	reserved: 2; 	/* reserved			  */
+		__u8	state	: 1; 	/* {0: free, 1: busy}		  */
+		__u8	reserved: 1; 	/* reserved			  */
 		__u8	entry_nr;    	/* specific enabled entry 	  */
 		__u8	default_vector; /* default pre-assigned vector    */
 		__u8	current_cpu; 	/* current destination cpu	  */

include/linux/pci.h

@@ -831,16 +831,27 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max, int pass
 extern struct pci_dev *isa_bridge;
 #endif
 
+struct msix_entry {
+	u16 	vector;	/* kernel uses to write allocated vector */
+	u16	entry;	/* driver uses to specify entry, OS writes */
+};
+
 #ifndef CONFIG_PCI_USE_VECTOR
 static inline void pci_scan_msi_device(struct pci_dev *dev) {}
 static inline int pci_enable_msi(struct pci_dev *dev) {return -1;}
+static inline void pci_disable_msi(struct pci_dev *dev) {}
+static inline int pci_enable_msix(struct pci_dev* dev,
+	struct msix_entry *entries, int nvec) {return -1;}
+static inline void pci_disable_msix(struct pci_dev *dev) {}
 static inline void msi_remove_pci_irq_vectors(struct pci_dev *dev) {}
 #else
 extern void pci_scan_msi_device(struct pci_dev *dev);
 extern int pci_enable_msi(struct pci_dev *dev);
+extern void pci_disable_msi(struct pci_dev *dev);
+extern int pci_enable_msix(struct pci_dev* dev,
+	struct msix_entry *entries, int nvec);
+extern void pci_disable_msix(struct pci_dev *dev);
 extern void msi_remove_pci_irq_vectors(struct pci_dev *dev);
-extern int msi_alloc_vectors(struct pci_dev* dev, int *vector, int nvec);
-extern int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec);
 #endif
 
 #endif /* CONFIG_PCI */