x86: acpi: Add wake up assembly stub

This adds a wake up stub before jumping to OS wake up vector.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Stefan Roese <sr@denx.de>

diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 92a9023..e1c84ce 100644 (file)
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -45,6 +45,7 @@ ifndef CONFIG_$(SPL_)X86_64
 obj-$(CONFIG_SMP) += sipi_vector.o
 endif
 obj-y += turbo.o
+obj-$(CONFIG_HAVE_ACPI_RESUME) += wakeup.o
 
 ifeq ($(CONFIG_$(SPL_)X86_64),y)
 obj-y += x86_64/

diff --git a/arch/x86/cpu/wakeup.S b/arch/x86/cpu/wakeup.S
new file mode 100644 (file)
index 0000000..066c9b1
--- /dev/null
+++ b/arch/x86/cpu/wakeup.S
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2017, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * From coreboot src/arch/x86/wakeup.S
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <asm/acpi_s3.h>
+#include <asm/processor.h>
+#include <asm/processor-flags.h>
+
+#define RELOCATED(x)   ((x) - __wakeup + WAKEUP_BASE)
+
+#define CODE_SEG       (X86_GDT_ENTRY_16BIT_CS * X86_GDT_ENTRY_SIZE)
+#define DATA_SEG       (X86_GDT_ENTRY_16BIT_DS * X86_GDT_ENTRY_SIZE)
+
+       .code32
+       .globl __wakeup
+__wakeup:
+       /* First prepare the jmp to the resume vector */
+       mov     0x4(%esp), %eax /* vector */
+       /* last 4 bits of linear addr are taken as offset */
+       andw    $0x0f, %ax
+       movw    %ax, (__wakeup_offset)
+       mov     0x4(%esp), %eax
+       /* the rest is taken as segment */
+       shr     $4, %eax
+       movw    %ax, (__wakeup_segment)
+
+       /* Activate the right segment descriptor real mode */
+       ljmp    $CODE_SEG, $RELOCATED(1f)
+1:
+       /* 16 bit code from here on... */
+       .code16
+
+       /*
+        * Load the segment registers w/ properly configured segment
+        * descriptors. They will retain these configurations (limits,
+        * writability, etc.) once protected mode is turned off.
+        */
+       mov     $DATA_SEG, %ax
+       mov     %ax, %ds
+       mov     %ax, %es
+       mov     %ax, %fs
+       mov     %ax, %gs
+       mov     %ax, %ss
+
+       /* Turn off protection */
+       movl    %cr0, %eax
+       andl    $~X86_CR0_PE, %eax
+       movl    %eax, %cr0
+
+       /* Now really going into real mode */
+       ljmp    $0, $RELOCATED(1f)
+1:
+       movw    $0x0, %ax
+       movw    %ax, %ds
+       movw    %ax, %es
+       movw    %ax, %ss
+       movw    %ax, %fs
+       movw    %ax, %gs
+
+       /*
+        * This is a FAR JMP to the OS waking vector.
+        * The C code changes the address to be correct.
+        */
+       .byte 0xea
+
+__wakeup_offset = RELOCATED(.)
+       .word 0x0000
+
+__wakeup_segment = RELOCATED(.)
+       .word 0x0000
+
+       .globl __wakeup_size
+__wakeup_size:
+       .long . - __wakeup

diff --git a/arch/x86/include/asm/acpi_s3.h b/arch/x86/include/asm/acpi_s3.h
index 10cedde..a06466c 100644 (file)
--- a/arch/x86/include/asm/acpi_s3.h
+++ b/arch/x86/include/asm/acpi_s3.h
@@ -7,6 +7,8 @@
 #ifndef __ASM_ACPI_S3_H__
 #define __ASM_ACPI_S3_H__
 
+#define WAKEUP_BASE    0x600
+
 /* PM1_STATUS register */
 #define WAK_STS                (1 << 15)
 #define PCIEXPWAK_STS  (1 << 14)
@@ -27,6 +29,11 @@
 #define SLP_TYP_S4     6
 #define SLP_TYP_S5     7
 
+#ifndef __ASSEMBLY__
+
+extern char __wakeup[];
+extern int __wakeup_size;
+
 enum acpi_sleep_state {
        ACPI_S0,
        ACPI_S1,
@@ -92,4 +99,6 @@ enum acpi_sleep_state chipset_prev_sleep_state(void);
  */
 void chipset_clear_sleep_state(void);
 
+#endif /* __ASSEMBLY__ */
+
 #endif /* __ASM_ACPI_S3_H__ */