gru: add MAX_SDRAM_FREQ config to choose max ddr freq

Gru/Kevin use the 933M(actually 928M for better jitter) as max sdram freq,
while bob would use 800M.

It's normal some variants can't meet 928M SI requirement and hence want
use a lower freq as spec.

BUG=chrome-os-partner:61001
BRANCH=gru
TEST=check dpll is 800M on bob

Change-Id: I46afba8d091f1489feeb20cafc44decaa81601fc
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Shunqian Zheng <zhengsq@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/420208
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Shasha Zhao <Sarah_Zhao@asus.com>
Tested-by: Shasha Zhao <Sarah_Zhao@asus.com>
(cherry picked from commit eba5dff79eeedae5ff608d2d8d297ccf9c13cb55)
Reviewed-on: https://chromium-review.googlesource.com/448277
Reviewed-by: Derek Basehore <dbasehore@chromium.org>

src/mainboard/google/gru/Kconfig

@@ -91,6 +91,13 @@ config MAINBOARD_PART_NUMBER
 	default "Gru" if BOARD_GOOGLE_GRU
 	default "Kevin" if BOARD_GOOGLE_KEVIN
 
+# The default max sdram freq is 933M(actually 928M dpll), and
+# 800M is another choice.
+config MAX_SDRAM_FREQ
+	int
+	default 800 if BOARD_GOOGLE_BOB
+	default 933
+
 config GBB_HWID
 	string
 	depends on CHROMEOS

src/mainboard/google/gru/Makefile.inc

@@ -13,7 +13,7 @@
 ## GNU General Public License for more details.
 ##
 
-subdirs-y += sdram_params/
+subdirs-y += sdram_params_$(CONFIG_MAX_SDRAM_FREQ)/
 
 bootblock-y += bootblock.c
 bootblock-y += chromeos.c

src/mainboard/google/gru/sdram_params_800/Makefile.inc

@@ -0,0 +1,27 @@
+##
+## This file is part of the coreboot project.
+##
+## Copyright 2017 Rockchip Inc.
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; version 2 of the License.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+
+sdram-params :=
+sdram-params += sdram-lpddr3-samsung-2GB-24EB
+sdram-params += sdram-lpddr3-micron-2GB
+sdram-params += sdram-lpddr3-samsung-4GB-04EB
+sdram-params += sdram-lpddr3-micron-4GB
+
+$(foreach params,$(sdram-params), \
+	$(eval cbfs-files-y += $(params)) \
+	$(eval $(params)-file := $(params).c:struct) \
+	$(eval $(params)-type := struct) \
+	$(eval $(params)-compression := $(CBFS_COMPRESS_FLAG)) \
+)