ahci: add "em_buffer" attribute for AHCI hosts

Add "em_buffer" attribute for SATA AHCI hosts to provide a way for
userland to access AHCI EM (enclosure management) buffer directly if the
host supports EM.

AHCI driver should support SGPIO EM messages. However the SATA/AHCI
specs did not define the SGPIO message format filled in EM buffer.
Different HW vendors may have different definitions. The mainly purpose
of this attribute is to solve this issue by allowing HW vendors to
provide userland drivers and tools for their SGPIO initiators.

Signed-off-by: Harry Zhang <harry.zhang@amd.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 5edce4447d84..7113c5724471 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -224,9 +224,12 @@ enum {
         EM_MAX_RETRY                    = 5,
 
         /* em_ctl bits */
-        EM_CTL_RST                      = (1 << 9), /* Reset */
-        EM_CTL_TM                       = (1 << 8), /* Transmit Message */
-        EM_CTL_ALHD                     = (1 << 26), /* Activity LED */
+        EM_CTL_RST              = (1 << 9), /* Reset */
+        EM_CTL_TM               = (1 << 8), /* Transmit Message */
+        EM_CTL_MR               = (1 << 0), /* Message Recieved */
+        EM_CTL_ALHD             = (1 << 26), /* Activity LED */
+        EM_CTL_XMT              = (1 << 25), /* Transmit Only */
+        EM_CTL_SMB              = (1 << 24), /* Single Message Buffer */
 
         /* em message type */
         EM_MSG_TYPE_LED         = (1 << 0), /* LED */
@@ -288,6 +291,7 @@ struct ahci_host_priv {
         u32                     saved_cap2;     /* saved initial cap2 */
         u32                     saved_port_map; /* saved initial port_map */
         u32                     em_loc; /* enclosure management location */
+        u32                     em_buf_sz;      /* EM buffer size in byte */
         u32                     em_msg_type;    /* EM message type */
 };