[SCSI] pm8001: set SSC down-spreading only to get less errors on some 6G device.

Signed-off-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 21 insertions, 44 deletions

diff --git a/drivers/scsi/pm8001/pm8001_hwi.c b/drivers/scsi/pm8001/pm8001_hwi.c
index b4426b5b50bc..6e1bdd8e680e 100644
--- a/drivers/scsi/pm8001/pm8001_hwi.c
+++ b/drivers/scsi/pm8001/pm8001_hwi.c
@@ -373,10 +373,7 @@ static int bar4_shift(struct pm8001_hba_info *pm8001_ha, u32 shiftValue)
 static void __devinit
 mpi_set_phys_g3_with_ssc(struct pm8001_hba_info *pm8001_ha, u32 SSCbit)
 {
-        u32 offset;
-        u32 value;
-        u32 i, j;
-        u32 bit_cnt;
+        u32 value, offset, i;
 
 #define SAS2_SETTINGS_LOCAL_PHY_0_3_SHIFT_ADDR 0x00030000
 #define SAS2_SETTINGS_LOCAL_PHY_4_7_SHIFT_ADDR 0x00040000
@@ -392,55 +389,35 @@ mpi_set_phys_g3_with_ssc(struct pm8001_hba_info *pm8001_ha, u32 SSCbit)
     */
         if (-1 == bar4_shift(pm8001_ha, SAS2_SETTINGS_LOCAL_PHY_0_3_SHIFT_ADDR))
                 return;
-        /* set SSC bit of PHY 0 - 3 */
+
         for (i = 0; i < 4; i++) {
                 offset = SAS2_SETTINGS_LOCAL_PHY_0_3_OFFSET + 0x4000 * i;
-                value = pm8001_cr32(pm8001_ha, 2, offset);
-                if (SSCbit) {
-                        value |= 0x00000001 << PHY_G3_WITH_SSC_BIT_SHIFT;
-                        value &= ~(0x00000001 << PHY_G3_WITHOUT_SSC_BIT_SHIFT);
-                } else {
-                        value |= 0x00000001 << PHY_G3_WITHOUT_SSC_BIT_SHIFT;
-                        value &= ~(0x00000001 << PHY_G3_WITH_SSC_BIT_SHIFT);
-                }
-                bit_cnt = 0;
-                for (j = 0; j < 31; j++)
-                        if ((value >> j) & 0x00000001)
-                                bit_cnt++;
-                if (bit_cnt % 2)
-                        value &= ~(0x00000001 << SNW3_PHY_CAPABILITIES_PARITY);
-                else
-                        value |= 0x00000001 << SNW3_PHY_CAPABILITIES_PARITY;
-
-                pm8001_cw32(pm8001_ha, 2, offset, value);
+                pm8001_cw32(pm8001_ha, 2, offset, 0x80001501);
         }
-
         /* shift membase 3 for SAS2_SETTINGS_LOCAL_PHY 4 - 7 */
         if (-1 == bar4_shift(pm8001_ha, SAS2_SETTINGS_LOCAL_PHY_4_7_SHIFT_ADDR))
                 return;
-
-        /* set SSC bit of PHY 4 - 7 */
         for (i = 4; i < 8; i++) {
                 offset = SAS2_SETTINGS_LOCAL_PHY_4_7_OFFSET + 0x4000 * (i-4);
-                value = pm8001_cr32(pm8001_ha, 2, offset);
-                if (SSCbit) {
-                        value |= 0x00000001 << PHY_G3_WITH_SSC_BIT_SHIFT;
-                        value &= ~(0x00000001 << PHY_G3_WITHOUT_SSC_BIT_SHIFT);
-                } else {
-                        value |= 0x00000001 << PHY_G3_WITHOUT_SSC_BIT_SHIFT;
-                        value &= ~(0x00000001 << PHY_G3_WITH_SSC_BIT_SHIFT);
-                }
-                bit_cnt = 0;
-                for (j = 0; j < 31; j++)
-                        if ((value >> j) & 0x00000001)
-                                bit_cnt++;
-                if (bit_cnt % 2)
-                        value &= ~(0x00000001 << SNW3_PHY_CAPABILITIES_PARITY);
-                else
-                        value |= 0x00000001 << SNW3_PHY_CAPABILITIES_PARITY;
-
-                pm8001_cw32(pm8001_ha, 2, offset, value);
+                pm8001_cw32(pm8001_ha, 2, offset, 0x80001501);
         }
+        /*************************************************************
+        Change the SSC upspreading value to 0x0 so that upspreading is disabled.
+        Device MABC SMOD0 Controls
+        Address: (via MEMBASE-III):
+        Using shifted destination address 0x0_0000: with Offset 0xD8
+
+        31:28 R/W Reserved Do not change
+        27:24 R/W SAS_SMOD_SPRDUP 0000
+        23:20 R/W SAS_SMOD_SPRDDN 0000
+        19:0  R/W  Reserved Do not change
+        Upon power-up this register will read as 0x8990c016,
+        and I would like you to change the SAS_SMOD_SPRDUP bits to 0b0000
+        so that the written value will be 0x8090c016.
+        This will ensure only down-spreading SSC is enabled on the SPC.
+        *************************************************************/
+        value = pm8001_cr32(pm8001_ha, 2, 0xd8);
+        pm8001_cw32(pm8001_ha, 2, 0xd8, 0x8000C016);
 
         /*set the shifted destination address to 0x0 to avoid error operation */
         bar4_shift(pm8001_ha, 0x0);