[U-Boot] [PATCH 11/22] x86: acpi: Resume OS if resume vector is found

[Stefan Roese]

Hi Bin,

On 12.04.2017 10:14, Bin Meng wrote:
> On Wed, Mar 22, 2017 at 4:06 AM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Bin,
>>
>> On 16 March 2017 at 08:26, Bin Meng <bmeng.cn at gmail.com> wrote:
>>> In an S3 resume path, U-Boot does everything like a cold boot except
>>> in the last_stage_init() it jumps to the OS resume vector.
>>>
>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>> ---
>>>
>>>  arch/x86/cpu/cpu.c             |  8 ++++++++
>>>  arch/x86/include/asm/acpi_s3.h | 10 ++++++++++
>>>  arch/x86/lib/Makefile          |  1 +
>>>  arch/x86/lib/acpi_s3.c         | 26 ++++++++++++++++++++++++++
>>>  4 files changed, 45 insertions(+)
>>>  create mode 100644 arch/x86/lib/acpi_s3.c
>>
>> Reviewed-by: Simon Glass <sjg at chromium.org>
>>
>>>
>>> diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
>>> index 9dde54c..afc8645 100644
>>> --- a/arch/x86/cpu/cpu.c
>>> +++ b/arch/x86/cpu/cpu.c
>>> @@ -26,6 +26,7 @@
>>>  #include <malloc.h>
>>>  #include <syscon.h>
>>>  #include <asm/acpi_s3.h>
>>> +#include <asm/acpi_table.h>
>>>  #include <asm/control_regs.h>
>>>  #include <asm/coreboot_tables.h>
>>>  #include <asm/cpu.h>
>>> @@ -204,6 +205,13 @@ __weak void board_final_cleanup(void)
>>>
>>>  int last_stage_init(void)
>>>  {
>>> +#if CONFIG_HAVE_ACPI_RESUME
>>> +       void *wake_vector = acpi_find_wakeup_vector();
>>> +
>>> +       if (wake_vector != NULL && gd->arch.prev_sleep_state == ACPI_S3)
>>> +               acpi_resume(wake_vector);
>>> +#endif
>>> +
>>>         write_tables();
>>>
>>>         board_final_cleanup();
>>> diff --git a/arch/x86/include/asm/acpi_s3.h b/arch/x86/include/asm/acpi_s3.h
>>> index f9d4739..5892a8b 100644
>>> --- a/arch/x86/include/asm/acpi_s3.h
>>> +++ b/arch/x86/include/asm/acpi_s3.h
>>> @@ -100,6 +100,16 @@ enum acpi_sleep_state chipset_prev_sleep_state(void);
>>>   */
>>>  void chipset_clear_sleep_state(void);
>>>
>>> +/**
>>> + * acpi_resume() - Do ACPI S3 resume
>>> + *
>>> + * This calls U-Boot wake up assembly stub and jumps to OS's wake up vector.
>>> + *
>>> + * @wake_vec:  OS wake up vector
>>> + * @return:    Never returns
>>> + */
>>> +void acpi_resume(void *wake_vec);
>>> +
>>>  #endif /* __ASSEMBLY__ */
>>>
>>>  #endif /* __ASM_ACPI_S3_H__ */
>>> diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
>>> index 1c2c085..c61f931 100644
>>> --- a/arch/x86/lib/Makefile
>>> +++ b/arch/x86/lib/Makefile
>>> @@ -35,6 +35,7 @@ obj-$(CONFIG_X86_RAMTEST) += ramtest.o
>>>  obj-y  += sections.o
>>>  obj-y += sfi.o
>>>  obj-y  += string.o
>>> +obj-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.o
>>>  ifndef CONFIG_QEMU
>>>  obj-$(CONFIG_GENERATE_ACPI_TABLE) += acpi_table.o
>>>  endif
>>> diff --git a/arch/x86/lib/acpi_s3.c b/arch/x86/lib/acpi_s3.c
>>> new file mode 100644
>>> index 0000000..f679c06
>>> --- /dev/null
>>> +++ b/arch/x86/lib/acpi_s3.c
>>> @@ -0,0 +1,26 @@
>>> +/*
>>> + * Copyright (C) 2017, Bin Meng <bmeng.cn at gmail.com>
>>> + *
>>> + * SPDX-License-Identifier:    GPL-2.0+
>>> + */
>>> +
>>> +#include <common.h>
>>> +#include <asm/acpi_s3.h>
>>> +#include <asm/post.h>
>>> +
>>> +static void asmlinkage (*acpi_do_wakeup)(void *vector) = (void *)WAKEUP_BASE;
>>> +
>>> +static void acpi_jump_to_wakeup(void *vector)
>>> +{
>>> +       /* Copy wakeup trampoline in place */
>>> +       memcpy((void *)WAKEUP_BASE, __wakeup, __wakeup_size);
>>> +
>>> +       printf("Jumping to OS waking vector %p\n", vector);
>>
>> Should this be debug()?
>>
> 
> I wanted to explicitly print this to show that we are in S3 and
> jumping to OS vector.

I also vote for this explicit print line in this case.

> Actually I was even thinking we should introduce
> a log level for U-Boot, just like coreboot/linux.

Interesting idea. How could the log-level be configured in U-Boot?
Via some env variable?

Thanks,
Stefan