[SCSI] mvsas: expander write performance enhancement

with 1 expander, connect 8 HDD, the write performance will be
improved by 80%.

Signed-off-by: Xiangliang Yu <yuxiangl@marvell.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/drivers/scsi/mvsas/mv_94xx.c b/drivers/scsi/mvsas/mv_94xx.c
index 016d3d41f23a..130d8036a2b5 100644
--- a/drivers/scsi/mvsas/mv_94xx.c
+++ b/drivers/scsi/mvsas/mv_94xx.c
@@ -510,6 +510,15 @@ static int __devinit mvs_94xx_init(struct mvs_info *mvi)
         tmp |= CINT_PHY_MASK;
         mw32(MVS_INT_MASK, tmp);
 
+        /* tune STP performance */
+        tmp = 0x003F003F;
+        mvs_cw32(mvi, CMD_PL_TIMER, tmp);
+
+        /* This can improve expander large block size seq write performance */
+        tmp = mvs_cr32(mvi, CMD_PORT_LAYER_TIMER1);
+        tmp |= 0xFFFF007F;
+        mvs_cw32(mvi, CMD_PORT_LAYER_TIMER1, tmp);
+
         /* change the connection open-close behavior (bit 9)
          * set bit8 to 1 for performance tuning */
         tmp = mvs_cr32(mvi, CMD_SL_MODE0);
diff --git a/drivers/scsi/mvsas/mv_defs.h b/drivers/scsi/mvsas/mv_defs.h
index dec7cadb7485..8e21482367d2 100644
--- a/drivers/scsi/mvsas/mv_defs.h
+++ b/drivers/scsi/mvsas/mv_defs.h
@@ -387,6 +387,7 @@ enum sas_cmd_port_registers {
         CMD_SL_MODE0            = 0x1BC, /* SL Mode 0 */
         CMD_SL_MODE1            = 0x1C0, /* SL Mode 1 */
         CMD_PND_FIFO_CTL1       = 0x1C4, /* Pending FIFO Control 1 */
+        CMD_PORT_LAYER_TIMER1   = 0x1E0, /* Port Layer Timer 1 */
 };
 
 enum mvs_info_flags {