[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 <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/pci/msi.h b/drivers/pci/msi.h
index 9b31d4cbbce4..62f61b61d2c9 100644
--- a/drivers/pci/msi.h
+++ b/drivers/pci/msi.h
@@ -130,10 +130,10 @@ struct msi_desc {
                 __u8    type    : 5;    /* {0: unused, 5h:MSI, 11h:MSI-X} */
                 __u8    maskbit : 1;    /* mask-pending bit supported ?   */
                 __u8    state   : 1;    /* {0: free, 1: busy}             */
-                __u8    reserved: 1;    /* reserved                       */
+                __u8    is_64   : 1;    /* Address size: 0=32bit 1=64bit  */
                 __u8    entry_nr;       /* specific enabled entry         */
                 __u8    default_vector; /* default pre-assigned vector    */
-                __u8    unused;         /* formerly unused destination cpu*/
+                __u8    pos;            /* Location of the msi capability */
         }msi_attrib;
 
         struct {
@@ -146,10 +146,7 @@ struct msi_desc {
 
 #ifdef CONFIG_PM
         /* PM save area for MSIX address/data */
-
-        u32     address_hi_save;
-        u32     address_lo_save;
-        u32     data_save;
+        struct msi_msg msg_save;
 #endif
 };