x86: Add an SPL implementation

SPL needs to set up the machine ready for loading 64-bit U-Boot and jumping
to it. Call the existing init routines in order to accomplish this.

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

arch/x86/include/asm/spl.h

@@ -0,0 +1,8 @@
+/*
+ * Copyright (C) 2017 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * This file is required for SPL to build, but is empty.
+ */

arch/x86/lib/Makefile

@@ -37,6 +37,7 @@ endif
 obj-y	+= tables.o
 obj-$(CONFIG_CMD_ZBOOT)	+= zimage.o
 obj-$(CONFIG_HAVE_FSP) += fsp/
+obj-$(CONFIG_SPL_BUILD) += spl.o
 
 extra-$(CONFIG_USE_PRIVATE_LIBGCC) += lib.a
 

arch/x86/lib/spl.c

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier:     GPL-2.0
+ */
+
+#include <common.h>
+#include <debug_uart.h>
+#include <spl.h>
+#include <asm/cpu.h>
+#include <asm/init_helpers.h>
+#include <asm/mtrr.h>
+#include <asm/processor.h>
+#include <asm-generic/sections.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int x86_spl_init(void)
+{
+	/*
+	 * TODO(sjg@chromium.org): We use this area of RAM for the stack
+	 * and global_data in SPL. Once U-Boot starts up and releocates it
+	 * is not needed. We could make this a CONFIG option or perhaps
+	 * place it immediately below CONFIG_SYS_TEXT_BASE.
+	 */
+	char *ptr = (char *)0x110000;
+	int ret;
+
+	debug("%s starting\n", __func__);
+	ret = spl_init();
+	if (ret) {
+		debug("%s: spl_init() failed\n", __func__);
+		return ret;
+	}
+	preloader_console_init();
+
+	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;
+	}
+	ret = print_cpuinfo();
+	if (ret) {
+		debug("%s: print_cpuinfo() failed\n", __func__);
+		return ret;
+	}
+	ret = dram_init();
+	if (ret) {
+		debug("%s: dram_init() failed\n", __func__);
+		return ret;
+	}
+	memset(&__bss_start, 0, (ulong)&__bss_end - (ulong)&__bss_start);
+
+	/* TODO(sjg@chromium.org): Consider calling cpu_init_r() here */
+	ret = interrupt_init();
+	if (ret) {
+		debug("%s: interrupt_init() failed\n", __func__);
+		return ret;
+	}
+
+	/*
+	 * The stack grows down from ptr. Put the global data at ptr. This
+	 * will only be used for SPL. Once SPL loads U-Boot proper it will
+	 * set up its own stack.
+	 */
+	gd->new_gd = (struct global_data *)ptr;
+	memcpy(gd->new_gd, gd, sizeof(*gd));
+	arch_setup_gd(gd->new_gd);
+	gd->start_addr_sp = (ulong)ptr;
+
+	/* Cache the SPI flash. Otherwise copying the code to RAM takes ages */
+	ret = mtrr_add_request(MTRR_TYPE_WRBACK,
+			       (1ULL << 32) - CONFIG_XIP_ROM_SIZE,
+			       CONFIG_XIP_ROM_SIZE);
+	if (ret) {
+		debug("%s: SPI cache setup failed\n", __func__);
+		return ret;
+	}
+
+	return 0;
+}
+
+void board_init_f(ulong flags)
+{
+	int ret;
+
+	ret = x86_spl_init();
+	if (ret) {
+		debug("Error %d\n", ret);
+		hang();
+	}
+
+	/* Uninit CAR and jump to board_init_f_r() */
+	board_init_f_r_trampoline(gd->start_addr_sp);
+}
+
+void board_init_f_r(void)
+{
+	init_cache_f_r();
+	gd->flags &= ~GD_FLG_SERIAL_READY;
+	debug("cache status %d\n", dcache_status());
+	board_init_r(gd, 0);
+}
+
+u32 spl_boot_device(void)
+{
+	return 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;
+	spl_image->entry_point = CONFIG_SYS_TEXT_BASE;
+	spl_image->load_addr = CONFIG_SYS_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)
+{
+	int ret;
+
+	printf("Jumping to 64-bit U-Boot: Note many features are missing\n");
+	ret = cpu_jump_to_64bit_uboot(spl_image->entry_point);
+	debug("ret=%d\n", ret);
+	while (1)
+		;
+}