x86: Add a simple TPL implementation

Add the required CPU code so that TPL builds correctly. Also update the
SPL code to deal with being booted from TPL.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/lib/tpl.c b/arch/x86/lib/tpl.c
new file mode 100644
index 0000000..492a2d6
--- /dev/null
+++ b/arch/x86/lib/tpl.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Google, Inc
+ */
+
+#include <common.h>
+#include <debug_uart.h>
+#include <spl.h>
+#include <asm/cpu.h>
+#include <asm/mtrr.h>
+#include <asm/processor.h>
+#include <asm-generic/sections.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+__weak int arch_cpu_init_dm(void)
+{
+	return 0;
+}
+
+static int x86_tpl_init(void)
+{
+	int ret;
+
+	debug("%s starting\n", __func__);
+	ret = spl_init();
+	if (ret) {
+		debug("%s: spl_init() failed\n", __func__);
+		return ret;
+	}
+	ret = arch_cpu_init();
+	if (ret) {
+		debug("%s: arch_cpu_init() failed\n", __func__);
+		return ret;
+	}
+	ret = arch_cpu_init_dm();
+	if (ret) {
+		debug("%s: arch_cpu_init_dm() failed\n", __func__);
+		return ret;
+	}
+	preloader_console_init();
+	ret = print_cpuinfo();
+	if (ret) {
+		debug("%s: print_cpuinfo() failed\n", __func__);
+		return ret;
+	}
+
+	return 0;
+}
+
+void board_init_f(ulong flags)
+{
+	int ret;
+
+	ret = x86_tpl_init();
+	if (ret) {
+		debug("Error %d\n", ret);
+		hang();
+	}
+
+	/* Uninit CAR and jump to board_init_f_r() */
+	board_init_r(gd, 0);
+}
+
+void board_init_f_r(void)
+{
+	/* Not used since we never call board_init_f_r_trampoline() */
+	while (1);
+}
+
+u32 spl_boot_device(void)
+{
+	return IS_ENABLED(CONFIG_CHROMEOS) ? BOOT_DEVICE_CROS_VBOOT :
+		BOOT_DEVICE_BOARD;
+}
+
+int spl_start_uboot(void)
+{
+	return 0;
+}
+
+void spl_board_announce_boot_device(void)
+{
+	printf("SPI flash");
+}
+
+static int spl_board_load_image(struct spl_image_info *spl_image,
+				struct spl_boot_device *bootdev)
+{
+	spl_image->size = CONFIG_SYS_MONITOR_LEN;  /* We don't know SPL size */
+	spl_image->entry_point = CONFIG_SPL_TEXT_BASE;
+	spl_image->load_addr = CONFIG_SPL_TEXT_BASE;
+	spl_image->os = IH_OS_U_BOOT;
+	spl_image->name = "U-Boot";
+
+	debug("Loading to %lx\n", spl_image->load_addr);
+
+	return 0;
+}
+SPL_LOAD_IMAGE_METHOD("SPI", 0, BOOT_DEVICE_BOARD, spl_board_load_image);
+
+int spl_spi_load_image(void)
+{
+	return -EPERM;
+}
+
+void __noreturn jump_to_image_no_args(struct spl_image_info *spl_image)
+{
+	printf("Jumping to U-Boot SPL at %lx\n", (ulong)spl_image->entry_point);
+	jump_to_spl(spl_image->entry_point);
+	while (1)
+		;
+}
+
+void spl_board_init(void)
+{
+	preloader_console_init();
+}