[PATCH] genirq: msi: implement helper functions read_msi_msg and write_msi_msg

In support of this I also add a struct msi_msg that captures the the two
address and one data field ina typical msi message, and I remember the pos and
if the address is 64bit in struct msi_desc.

This makes the code a little more readable and easier to maintain, and paves
the way to further simplfications.

Signed-off-by: Eric W. Biederman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Rajesh Shah <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: "Protasevich, Natalie" <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 4431ce4e1e6f..b9bb6c46e056 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -595,6 +595,12 @@ struct msix_entry {
 	u16	entry;	/* driver uses to specify entry, OS writes */
 };
 
+struct msi_msg {
+	u32	address_lo;	/* low 32 bits of msi message address */
+	u32	address_hi;	/* high 32 bits of msi message address */
+	u32	data;		/* 16 bits of msi message data */
+};
+
 #ifndef CONFIG_PCI_MSI
 static inline void pci_scan_msi_device(struct pci_dev *dev) {}
 static inline int pci_enable_msi(struct pci_dev *dev) {return -1;}