PCI: add OBFF enable/disable support

OBFF (optimized buffer flush/fill), where supported, can help improve
energy efficiency by giving devices information about when interrupts
and other activity will have a reduced power impact.  It requires
support from both the device and system (i.e. not only does the device
need to respond to OBFF messages, but the platform must be capable of
generating and routing them to the end point).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index d9acf9b..aa42026 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -508,10 +508,16 @@
 #define PCI_EXP_RTSTA_PENDING	0x20000 /* PME pending */
 #define PCI_EXP_DEVCAP2		36	/* Device Capabilities 2 */
 #define  PCI_EXP_DEVCAP2_ARI	0x20	/* Alternative Routing-ID */
+#define  PCI_EXP_OBFF_MASK	0xc0000 /* OBFF support mechanism */
+#define  PCI_EXP_OBFF_MSG	0x40000 /* New message signaling */
+#define  PCI_EXP_OBFF_WAKE	0x80000 /* Re-use WAKE# for OBFF */
 #define PCI_EXP_DEVCTL2		40	/* Device Control 2 */
 #define  PCI_EXP_DEVCTL2_ARI	0x20	/* Alternative Routing-ID */
 #define  PCI_EXP_IDO_REQ_EN	0x100	/* ID-based ordering request enable */
 #define  PCI_EXP_IDO_CMP_EN	0x200	/* ID-based ordering completion enable */
+#define  PCI_EXP_OBFF_MSGA_EN	0x2000	/* OBFF enable with Message type A */
+#define  PCI_EXP_OBFF_MSGB_EN	0x4000	/* OBFF enable with Message type B */
+#define  PCI_EXP_OBFF_WAKE_EN	0x6000	/* OBFF using WAKE# signaling */
 #define PCI_EXP_LNKCTL2		48	/* Link Control 2 */
 #define PCI_EXP_SLTCTL2		56	/* Slot Control 2 */