mb/dell/optiplex_9010/sch5545_ec.c: Fix HWM initialization bugs

Fix the HWM sequence matching to the chassis. HWM sequence for SFF
was incorrectly passed to MT chassis HWM initialization.

Vendor code also applies a fix-up for MT/DT chassis. This fixup was
missing one register read compared to the vendor code. Add the missing
read and guard the fixup depening on the returned value to match the
vendor code behavior. Not doing so resulted in increased fan speeds
on Dell Precision T1650 compared to Dell's firmware.

TEST=Boot Dell Precision T1650 and hear the fans are as silent as on
Dell's firmware

Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Change-Id: I5c0e1c00e69d66848a602ad91a3e83375a095f44
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62210
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Krystian Hebel <krystian.hebel@3mdeb.com>

1 files changed, 24 insertions, 20 deletions

diff --git a/src/mainboard/dell/optiplex_9010/sch5545_ec.c b/src/mainboard/dell/optiplex_9010/sch5545_ec.c
index fa78a98b73..9aa0038cc3 100644
--- a/src/mainboard/dell/optiplex_9010/sch5545_ec.c
+++ b/src/mainboard/dell/optiplex_9010/sch5545_ec.c
@@ -548,17 +548,17 @@ static uint8_t get_chassis_type(void)
 	switch (chassis_id) {
 	case 0x0:
 	case 0x4:
-		return 5;
+		return 5; /* MT */
 	case 0x8:
-		return 4;
+		return 4; /* DT */
 	case 0x3:
 	case 0xb:
-		return 3;
+		return 3; /* USFF */
 	case 0x1:
 	case 0x9:
 	case 0x5:
 	case 0xd:
-		return 6;
+		return 6; /* SFF */
 	default:
 		printk(BIOS_DEBUG, "Unknown chassis ID %x\n", chassis_id);
 		break;
@@ -640,7 +640,7 @@ void sch5545_ec_hwm_init(void *unused)
 			ec_hwm_init_late(ec_hwm_chassis4, ARRAY_SIZE(ec_hwm_chassis4));
 			break;
 		case 5:
-			ec_hwm_init_late(ec_hwm_chassis6, ARRAY_SIZE(ec_hwm_chassis5));
+			ec_hwm_init_late(ec_hwm_chassis5, ARRAY_SIZE(ec_hwm_chassis5));
 			break;
 		case 6:
 			ec_hwm_init_late(ec_hwm_chassis6, ARRAY_SIZE(ec_hwm_chassis6));
@@ -673,21 +673,25 @@ void sch5545_ec_hwm_init(void *unused)
 	ec_read_write_reg(EC_HWM_LDN, 0x00b8, &val, READ_OP);
 
 	if (chassis_type == 4 || chassis_type == 5) {
-		ec_read_write_reg(EC_HWM_LDN, 0x00a0, &val, READ_OP);
-		val &= 0xfb;
-		ec_read_write_reg(EC_HWM_LDN, 0x00a0, &val, WRITE_OP);
-		ec_read_write_reg(EC_HWM_LDN, 0x00a1, &val, READ_OP);
-		val &= 0xfb;
-		ec_read_write_reg(EC_HWM_LDN, 0x00a1, &val, WRITE_OP);
-		ec_read_write_reg(EC_HWM_LDN, 0x00a2, &val, READ_OP);
-		val &= 0xfb;
-		ec_read_write_reg(EC_HWM_LDN, 0x00a2, &val, WRITE_OP);
-		val = 0x99;
-		ec_read_write_reg(EC_HWM_LDN, 0x008a, &val, WRITE_OP);
-		val = 0x47;
-		ec_read_write_reg(EC_HWM_LDN, 0x008b, &val, WRITE_OP);
-		val = 0x91;
-		ec_read_write_reg(EC_HWM_LDN, 0x008c, &val, WRITE_OP);
+		ec_read_write_reg(EC_HWM_LDN, 0x0027, &val, READ_OP);
+		if (val == 0) {
+			printk(BIOS_INFO, "Applying HWM fix-up for MT/DT chassis\n");
+			ec_read_write_reg(EC_HWM_LDN, 0x00a0, &val, READ_OP);
+			val &= 0xfb;
+			ec_read_write_reg(EC_HWM_LDN, 0x00a0, &val, WRITE_OP);
+			ec_read_write_reg(EC_HWM_LDN, 0x00a1, &val, READ_OP);
+			val &= 0xfb;
+			ec_read_write_reg(EC_HWM_LDN, 0x00a1, &val, WRITE_OP);
+			ec_read_write_reg(EC_HWM_LDN, 0x00a2, &val, READ_OP);
+			val &= 0xfb;
+			ec_read_write_reg(EC_HWM_LDN, 0x00a2, &val, WRITE_OP);
+			val = 0x99;
+			ec_read_write_reg(EC_HWM_LDN, 0x008a, &val, WRITE_OP);
+			val = 0x47;
+			ec_read_write_reg(EC_HWM_LDN, 0x008b, &val, WRITE_OP);
+			val = 0x91;
+			ec_read_write_reg(EC_HWM_LDN, 0x008c, &val, WRITE_OP);
+		}
 	}
 
 	ec_read_write_reg(EC_HWM_LDN, 0x0049, &val, READ_OP);