x86: Support QEMU x86 targets

This commit introduces the initial U-Boot support for QEMU x86 targets.
U-Boot can boot from coreboot as a payload, or directly without coreboot.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Merged in patch 'x86: qemu: Add CMD_NET to qemu-x86_defconfig
   https://patchwork.ozlabs.org/patch/479745/

1 files changed, 46 insertions, 0 deletions

diff --git a/arch/x86/cpu/qemu/dram.c b/arch/x86/cpu/qemu/dram.c
new file mode 100644
index 0000000..a88d0d2
--- /dev/null
+++ b/arch/x86/cpu/qemu/dram.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/post.h>
+#include <asm/arch/qemu.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	u32 ram;
+
+	outb(HIGH_RAM_ADDR, CMOS_ADDR_PORT);
+	ram = ((u32)inb(CMOS_DATA_PORT)) << 14;
+	outb(LOW_RAM_ADDR, CMOS_ADDR_PORT);
+	ram |= ((u32)inb(CMOS_DATA_PORT)) << 6;
+	ram += 16 * 1024;
+
+	gd->ram_size = ram * 1024;
+	post_code(POST_DRAM);
+
+	return 0;
+}
+
+void dram_init_banksize(void)
+{
+	gd->bd->bi_dram[0].start = 0;
+	gd->bd->bi_dram[0].size = gd->ram_size;
+}
+
+/*
+ * This function looks for the highest region of memory lower than 4GB which
+ * has enough space for U-Boot where U-Boot is aligned on a page boundary.
+ * It overrides the default implementation found elsewhere which simply
+ * picks the end of ram, wherever that may be. The location of the stack,
+ * the relocation address, and how far U-Boot is moved by relocation are
+ * set in the global data structure.
+ */
+ulong board_get_usable_ram_top(ulong total_size)
+{
+	return gd->ram_size;
+}