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

[Simon Glass]

Hi Stefan,

On 17 April 2017 at 03:37, Stefan Roese <sr at denx.de> wrote:
> 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?

Yes I suppose so.

Regards,
Simon