x86: broadwell: Allow booting from SPL

At present broadwell only supports booting straight into U-Boot proper.
Add a separate init file to boot from SPL into U-Boot proper, and select
it when SPL is in use.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/cpu/broadwell/Makefile

@@ -5,6 +5,21 @@
 obj-y += adsp.o
 obj-y += cpu.o
 obj-y += cpu_full.o
+
+ifdef CONFIG_SPL
+ifndef CONFIG_SPL_BUILD
+obj-y += cpu_from_spl.o
+obj-y += cpu_full.o
+endif
+ifndef CONFIG_SPL_BUILD
+# obj-y += cpu_from_spl.o
+endif
+endif
+
+ifeq ($(CONFIG_$(SPL_TPL_)X86_32BIT_INIT),)
+#obj-y += cpu_from_spl.o
+endif
+
 obj-y += iobp.o
 obj-y += lpc.o
 obj-y += me.o

arch/x86/cpu/broadwell/cpu_from_spl.c

@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2016 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bloblist.h>
+#include <debug_uart.h>
+#include <handoff.h>
+#include <asm/mtrr.h>
+
+int misc_init_r(void)
+{
+	return 0;
+}
+
+int dram_init(void)
+{
+	struct spl_handoff *ho;
+
+	ho = bloblist_find(BLOBLISTT_SPL_HANDOFF, sizeof(*ho));
+	if (!ho)
+		return log_msg_ret("Missing SPL hand-off info", -ENOENT);
+	handoff_load_dram_size(ho);
+#ifdef CONFIG_TPL
+	/* TODO(sjg@chromium.org): MTRR cannot be adjusted without a hang */
+	mtrr_add_request(MTRR_TYPE_WRBACK, 0, 2ULL << 30);
+#else
+	mtrr_add_request(MTRR_TYPE_WRBACK, 0, gd->ram_size);
+	mtrr_commit(true);
+#endif
+
+	return 0;
+}
+
+int checkcpu(void)
+{
+	return 0;
+}
+
+int print_cpuinfo(void)
+{
+	return 0;
+}
+
+void board_debug_uart_init(void)
+{
+}
+
+int dram_init_banksize(void)
+{
+#ifdef CONFIG_NR_DRAM_BANKS
+	struct spl_handoff *ho;
+
+	ho = bloblist_find(BLOBLISTT_SPL_HANDOFF, sizeof(*ho));
+	if (!ho)
+		return log_msg_ret("Missing SPL hand-off info", -ENOENT);
+	handoff_load_dram_banks(ho);
+#endif
+
+	return 0;
+}