From 5d997f9459e95c52ed70f98ab0db2320cf8d6238 Mon Sep 17 00:00:00 2001 From: Ionela Voinescu Date: Mon, 30 Mar 2015 12:00:35 +0100 Subject: [PATCH] imgtec/pistachio: DDR reads return to controller with no bubbles When the PHY is compiled to run in HDR(half data rate), then either NOBUB or FXDAT must be set to 1 in the DDR system general configuration register. NOBUB specifies that reads should be returned to the controller with no bubbles and this is felt preferable to the fixed latency option (FXDAT). Both of them inrease read latency. BRANCH=none BUG=chrome-os-partner:37087 TEST=tested on Pistachio bring up board -> DDR initialized properly and ramstage executed correctly Change-Id: Iee530ba5bb0acc889fba447dc2ee5cb965ba6926 Signed-off-by: Patrick Georgi Original-Commit-Id: e7944b4af45d9504098f8b4af44d0f5abafea42c Original-Change-Id: I9ced76bd670fc4efa7441d57e15f97871b046ae9 Original-Signed-off-by: Ionela Voinescu Original-Reviewed-on: https://chromium-review.googlesource.com/264341 Original-Reviewed-by: James Hartley Original-Reviewed-by: David Hendricks Reviewed-on: http://review.coreboot.org/9917 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer --- src/soc/imgtec/pistachio/ddr2_init.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/soc/imgtec/pistachio/ddr2_init.c b/src/soc/imgtec/pistachio/ddr2_init.c index 66b8778c48..f47b24f348 100644 --- a/src/soc/imgtec/pistachio/ddr2_init.c +++ b/src/soc/imgtec/pistachio/ddr2_init.c @@ -259,7 +259,7 @@ int init_ddr2(void) * 4 LPDLLPD DEf 1 0 * 7:5 DQSGX DQS Extention 000 * 10:8 DQSGE DQS Early Gate - * 11 NOBUB No Bubbles, adds latency 0 + * 11 NOBUB No Bubbles, adds latency 1 * 12 FXDLAT Fixed Read Latency 0 * 15:13 Reserved * 19:16 CKEPDD CKE Power Down 0000 @@ -273,7 +273,7 @@ int init_ddr2(void) * 30 RSTOE RST# Output Enable 1 * 31 CKEOE CKE Output Enable 1 */ - write32(DDR_PHY + DDRPHY_DSGCR_OFFSET, 0xF2000007); + write32(DDR_PHY + DDRPHY_DSGCR_OFFSET, 0xF2000807); /* DTPR0 : DRAM Timing Params 0 * 1:0 tMRD 2 * 4:2 tRTP 3