Re: [PATCH] sh: hibernation support

[Magnus Damm <magnus.damm@gmail.com>]

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On Fri, Mar 6, 2009 at 4:06 PM, Francesco VIRLINZI
<francesco.virlinzi@st.com> wrote:
> Hi Magnus
> I was looking your patch and I have few question.

Great! You should try in on some ST hardware as well. =)

> Is it also for sh4 with PMB? If so how are you managing the PMB?
> Moreover what about interrupt controller? This means after a resume from
> hibernation
> you could have a resumed device (and driver) but the interrupt controller
> has the right irq-line not initialized.

I have not tested with PMB. You are right about the interrupt
controller, but it works because swsusp resume boots up the system as
usual with an identical kernel. Look at the attached file for the
swsusp code flow...

Cheers,

/ magnus

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CONFIG_HIBERNATE in 2.6.29

suspend operation 
------------------
swsusp code                        arch code           driver callbacks

hibernate(): [disk.c]
  hibernation_snapshot()

hibernation_snapshot():
  suspend_console()
  device_suspend(PMSG_FREEZE)                          prepare(), freeze()
  disable_nonboot_cpus()
  create_image()

create_image():
  arch_prepare_suspend()           do nothing
  local_irq_disable()
  device_power_down(PMSG_FREEZE)                       freeze_noirq()
  save_processor_state()           save registers
  swsusp_arch_suspend()            call swsusp_save()

swsusp_save() [snapshot.c]
  create hibernation image

create_image(): [disk.c]
  restore_processor_state()        restore registers
  device_power_up(PMSG_THAW)                           thaw_noirq()
  local_irq_enable()
  
hibernation_snapshot()
  enable_nonboot_cpus()
  device_resume(PMSG_THAW)                             thaw(), complete()
  resume_console()

hibernate():
  swsusp_write()
  swsusp_free()
  power_down()

power_down():
  hibernation_platform_enter()

hibernation_platform_enter():
  suspend_console()
  device_suspend(PMSG_HIBERNATE)                       prepare(), poweroff()
  disable_nonboot_cpus()
  local_irq_disable()
  device_power_down(PMSG_HIBERNATE)                    poweroff_noirq()


resume operation:
-----------------
swsusp code                        arch code           driver callbacks

software_resume() [disk.c]
  swsusp_check()
  swsusp_read()
  hibernation_restore()

hibernation_restore()
  suspend_console()
  device_suspend(PMSG_QUIESCE)                         prepare(), freeze()
  disable_nonboot_cpus()
  resume_target_kernel()

resume_target_kernel()
  local_irq_disable()
  device_power_down(PMSG_QUIESCE)                      freeze_noirq()
  save_processor_state()           save registers
  restore_highmem()
  swsusp_arch_resume()             overwrite memory

  [executing old image now, back in suspend path with in_suspend = 0]

create_image():
  restore_processor_state()        restore registers
  device_power_up(PMSG_RESTORE)                        restore_noirq()
  local_irq_enable()
  
hibernation_snapshot()
  enable_nonboot_cpus()
  device_resume(PMSG_RESTORE)                          restore(), complete()
  resume_console()

hibernate():
  swsusp_free()