x86: Add support for starting from SPL/TPL
When a previous phase of U-Boot has run we need to adjust the init of
subsequent states to avoid messing up the CPU state.
Add a new version of the start logic for SPL, when it boots from TPL
(start_from tpl.c) and a new version for U-Boot when it boots from SPL.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index fec1484..9fd6cf2 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -4,9 +4,21 @@
ifdef CONFIG_$(SPL_)X86_64
head-y := arch/x86/cpu/start64.o
else
+ifeq ($(CONFIG_$(SPL_TPL_)X86_16BIT_INIT),y)
head-y := arch/x86/cpu/start.o
+else
+ifndef CONFIG_SPL
+head-y := arch/x86/cpu/start.o
+else
+ifdef CONFIG_SPL_BUILD
+head-y = arch/x86/cpu/start_from_tpl.o
+else
+head-y = arch/x86/cpu/start_from_spl.o
endif
endif
+endif
+endif
+endif # EFI
head-$(CONFIG_$(SPL_)X86_16BIT_INIT) += arch/x86/cpu/start16.o
head-$(CONFIG_$(SPL_)X86_16BIT_INIT) += arch/x86/cpu/resetvec.o
diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 54668aa..85fd5e6 100644
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -9,9 +9,22 @@
ifeq ($(CONFIG_$(SPL_)X86_64),y)
extra-y = start64.o
else
+ifeq ($(CONFIG_$(SPL_TPL_)X86_16BIT_INIT),y)
extra-y = start.o
+else
+ifndef CONFIG_SPL
+extra-y = start.o
+else
+ifdef CONFIG_SPL_BUILD
+extra-y = start_from_tpl.o
+else
+extra-y = start_from_spl.o
endif
-extra-$(CONFIG_$(SPL_)X86_16BIT_INIT) += resetvec.o start16.o
+endif
+endif
+endif
+
+extra-$(CONFIG_$(SPL_TPL_)X86_16BIT_INIT) += resetvec.o start16.o
obj-y += cpu.o cpu_x86.o
diff --git a/arch/x86/cpu/start_from_spl.S b/arch/x86/cpu/start_from_spl.S
new file mode 100644
index 0000000..4d4e5d0
--- /dev/null
+++ b/arch/x86/cpu/start_from_spl.S
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * 32-bit x86 Startup Code when running from SPL
+ *
+ * Copyright 2018 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <config.h>
+
+.section .text.start
+.code32
+.globl _start
+.type _start, @function
+_start:
+ /* Set up memory using the existing stack */
+ movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %eax
+#ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE
+ subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %eax
+#endif
+ /*
+ * We don't subject CONFIG_DCACHE_RAM_MRC_VAR_SIZE since memory is
+ * already set up. This has the happy side-effect of putting gd in a
+ * new place separate from SPL, so the memset() in
+ * board_init_f_init_reserve() does not cause any problems (otherwise
+ * it would zero out the gd and crash)
+ */
+ call board_init_f_alloc_reserve
+ mov %eax, %esp
+
+ call board_init_f_init_reserve
+
+ xorl %eax, %eax
+ call board_init_f
+ call board_init_f_r
+
+ /* Should not return here */
+ jmp .
+
+.globl board_init_f_r_trampoline
+.type board_init_f_r_trampoline, @function
+board_init_f_r_trampoline:
+ /*
+ * SPL has been executed and SDRAM has been initialised, U-Boot code
+ * has been copied into RAM, BSS has been cleared and relocation
+ * adjustments have been made. It is now time to jump into the in-RAM
+ * copy of U-Boot
+ *
+ * %eax = Address of top of new stack
+ */
+
+ /* Stack grows down from top of SDRAM */
+ movl %eax, %esp
+
+ /* Re-enter U-Boot by calling board_init_f_r() */
+ call board_init_f_r
+
+die:
+ hlt
+ jmp die
+ hlt
+
+ .align 4
+_dt_ucode_base_size:
+ /* These next two fields are filled in by binman */
+.globl ucode_base
+ucode_base: /* Declared in microcode.h */
+ .long 0 /* microcode base */
+.globl ucode_size
+ucode_size: /* Declared in microcode.h */
+ .long 0 /* microcode size */
diff --git a/arch/x86/cpu/start_from_tpl.S b/arch/x86/cpu/start_from_tpl.S
new file mode 100644
index 0000000..44b5363
--- /dev/null
+++ b/arch/x86/cpu/start_from_tpl.S
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * 32-bit x86 Startup Code when running from TPL
+ *
+ * Copyright 2018 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <config.h>
+
+.section .text.start
+.code32
+.globl _start
+.type _start, @function
+_start:
+ /* Set up memory using the existing stack */
+ mov %esp, %eax
+ call board_init_f_alloc_reserve
+ mov %eax, %esp
+
+ call board_init_f_init_reserve
+
+ xorl %eax, %eax
+ call board_init_f
+ call board_init_f_r
+
+ /* Should not return here */
+ jmp .
+
+.globl board_init_f_r_trampoline
+.type board_init_f_r_trampoline, @function
+board_init_f_r_trampoline:
+ /*
+ * TPL has been executed: SDRAM has been initialised, BSS has been
+ * cleared.
+ *
+ * %eax = Address of top of new stack
+ */
+
+ /* Stack grows down from top of SDRAM */
+ movl %eax, %esp
+
+ /* Re-enter SPL by calling board_init_f_r() */
+ call board_init_f_r
+
+die:
+ hlt
+ jmp die
+ hlt