intel post-car: Consolidate choose_top_of_stack()

Change-Id: I2c49d68ea9a8f52737b6064bc4fa703bdb1af1df
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/15463
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/lib/Makefile.inc

@@ -78,6 +78,7 @@ romstage-$(CONFIG_PRIMITIVE_MEMTEST) += primitive_memtest.c
 ramstage-$(CONFIG_PRIMITIVE_MEMTEST) += primitive_memtest.c
 romstage-$(CONFIG_CACHE_AS_RAM) += ramtest.c
 romstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
+romstage-y += romstage_stack.c
 romstage-y += stack.c
 ramstage-y += rtc.c
 

src/lib/romstage_stack.c

@@ -0,0 +1,48 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013 Google Inc.
+ * Copyright (C) 2015-2016 Intel Corp.
+ *
+ * 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.
+ */
+
+#include <program_loading.h>
+#include <cbmem.h>
+
+/*
+ * Romstage needs quite a bit of stack for decompressing images since the lzma
+ * lib keeps its state on the stack during romstage.
+ */
+#define ROMSTAGE_RAM_STACK_SIZE 0x5000
+
+uintptr_t romstage_ram_stack_base(size_t size, int src)
+{
+	/* cbmem_add() does a find() before add(). */
+	if (src == ROMSTAGE_STACK_CBMEM)
+		return (uintptr_t)cbmem_add(CBMEM_ID_ROMSTAGE_RAM_STACK, size);
+	if (src == ROMSTAGE_STACK_LOW_MEM)
+		return CONFIG_RAMTOP - size;
+	return 0;
+}
+
+uintptr_t romstage_ram_stack_bottom(void)
+{
+	return romstage_ram_stack_base(ROMSTAGE_RAM_STACK_SIZE,
+		ROMSTAGE_STACK_CBMEM);
+}
+
+uintptr_t romstage_ram_stack_top(void)
+{
+	uintptr_t stack_top = romstage_ram_stack_base(ROMSTAGE_RAM_STACK_SIZE,
+		ROMSTAGE_STACK_CBMEM);
+	stack_top += ROMSTAGE_RAM_STACK_SIZE;
+	return stack_top;
+}