nb/intel/sandybridge/raminit: Fix PDWN_mode on desktops

On desktop boards the PPD bit of MRS register MR0 is set and thus
DLL_Off mode shouldn't be used, as enforced by datasheet
2nd-gen-core-family-mobile-vol-2-datasheet chapter 2.17.1.

Change-Id: Ic42f2ff3e719636be67b00fa37155939cd2e17de
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/22260
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/northbridge/intel/sandybridge/raminit_common.c b/src/northbridge/intel/sandybridge/raminit_common.c
index 3e769ec..44f7f6d 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.c
+++ b/src/northbridge/intel/sandybridge/raminit_common.c
@@ -3202,7 +3202,14 @@
 
 	write32(DEFAULT_MCHBAR + 0x400c, (read32(DEFAULT_MCHBAR + 0x400c) & 0xFFFFCFFF) | 0x1000);	// OK
 	write32(DEFAULT_MCHBAR + 0x440c, (read32(DEFAULT_MCHBAR + 0x440c) & 0xFFFFCFFF) | 0x1000);	// OK
-	write32(DEFAULT_MCHBAR + 0x4cb0, 0x00000740);
+
+	if (ctrl->mobile)
+		/* APD - DLL Off, 64 DCLKs until idle, decision per rank */
+		MCHBAR32(PM_PDWN_Config) = 0x00000740;
+	else
+		/* APD - PPD, 64 DCLKs until idle, decision per rank */
+		MCHBAR32(PM_PDWN_Config) = 0x00000340;
+
 	write32(DEFAULT_MCHBAR + 0x4380, 0x00000aaa);	// OK
 	write32(DEFAULT_MCHBAR + 0x4780, 0x00000aaa);	// OK
 	write32(DEFAULT_MCHBAR + 0x4f88, 0x5f7003ff);	// OK