[PATCH/RFC] ARM: shmobile: sh7372: Keep D4 pm domain powered

[Simon Horman]

On Tue, Oct 28, 2014 at 09:16:43AM +0900, Simon Horman wrote:
> On Mon, Oct 27, 2014 at 09:23:14AM +0100, Geert Uytterhoeven wrote:
> > Hi Simon,
> > 
> > On Mon, Oct 27, 2014 at 2:08 AM, Simon Horman <horms at verge.net.au> wrote:
> > > On Thu, Oct 23, 2014 at 01:31:14PM +0200, Geert Uytterhoeven wrote:
> > >> The D4 power domain contains the Coresight-ETM hardware block.
> > >> As long as the ARM debug/perf code doesn't use resource management with
> > >> runtime PM support, the D4 power domain must be kept powered to avoid a
> > >> crash during resume from s2ram (dbg_cpu_pm_notify() calls
> > >> reset_ctrl_regs() unconditionally, causing an undefined instruction
> > >> oops).
> > >>
> > >> Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
> > >> ---
> > >> Untested on real hardware, but a similar workaround is needed on r8a7740.
> > >
> > > I have hardware in the form of a Mackerel board and I'm happy
> > > to test this if it would help and you give me some guidance on how to do so.
> > 
> > That would be great!
> > 
> > Test procedure:
> >   1. echo 0 > /sys/module/printk/parameters/console_suspend
> 
> I seemed to also need:
> 
> echo enabled > /sys/devices/platform/sh-sci.0/tty/ttySC0/power/wakeup
> 
> >   2. echo mem > /sys/power/state
> >   3. [ Wake up by pressing a key on the serial console.
> >         There's no other wake-up source on mackerel? ]
> 
> usbhs seems like a candidate, it has a wakeup node in sysfs.
> 
> > Without my patch, I expect it to crash during resume in reset_ctrl_regs().

For the record the tests below were performed using
renesas-devel-20141028-v3.18-rc2 with and without your patch.

> With the patch and the mackerel defconfig I see this:
> 
> # echo mem > /sys/power/state
> PM: Syncing filesystems ... done.
> Freezing user space processes ... (elapsed 0.005 seconds) done.
> Freezing remaining freezable tasks ... (elapsed 0.009 seconds) done.
> Suspending console(s) (use no_console_suspend to debug)
> dpm_run_callback(): pm_genpd_suspend+0x0/0x44 returns -16
> PM: Device sh_mobile_sdhi.2 failed to suspend: error -16
> PM: Some devices failed to suspend, or early wake event detected
> PM: resume of devices complete after 0.323 msecs
> Restarting tasks ... done.
> -bash: echo: write error: Device or resource busy
> #
> 
> So I turned of SDHI support in the kernel config and tried again:
> 
> # echo mem > /sys/power/state
> PM: Syncing filesystems ... done.
> Freezing user space processes ... (elapsed 0.008 seconds) done.
> Freezing remaining freezable tasks ... (elapsed 0.009 seconds) done.
> renesas_usbhs renesas_usbhs.1: remove, state 4
> usb usb1: USB disconnect, device number 1
> renesas_usbhs renesas_usbhs.1: USB bus 1 deregistered
> PM: suspend of devices complete after 28.959 msecs
> PM: late suspend of devices complete after 0.357 msecs
> PM: noirq suspend of devices complete after 0.512 msecs
> 
> [keypress]
> 
> sh_tmu sh-tmu.0: ch0: used for periodic clock events
> PM: noirq resume of devices complete after 0.420 msecs
> PM: early resume of devices complete after 0.209 msecs
> PM: resume of devices complete after 0.327 msecs
> Restarting tasks ... 
> 
> renesas_usbhs renesas_usbhs.1: USB Host Controller
> renesas_usbhs renesas_usbhs.1: new USB bus registered, assigned bus number 1
> done.
> hub 1-0:1.0: USB hub found
> hub 1-0:1.0: 1 port detected
> asoc-simple-card asoc-simple-card.0: ASoC: CODEC DAI ak4642-hifi not registered
> platform asoc-simple-card.0: Driver asoc-simple-card requests probe deferral
> 
> 
> Without the patch I see the same as above, module slightly different msec
> values:
> 
> # echo mem > /sys/power/state
> PM: Syncing filesystems ... done.
> Freezing user space processes ... (elapsed 0.004 seconds) done.
> Freezing remaining freezable tasks ... (elapsed 0.009 seconds) done.
> renesas_usbhs renesas_usbhs.1: remove, state 4
> usb usb1: USB disconnect, device number 1
> renesas_usbhs renesas_usbhs.1: USB bus 1 deregistered
> PM: suspend of devices complete after 27.306 msecs
> PM: late suspend of devices complete after 0.343 msecs
> PM: noirq suspend of devices complete after 0.503 msecs
> 
> [keypress]
> 
> sh_tmu sh-tmu.0: ch0: used for periodic clock events
> PM: noirq resume of devices complete after 0.420 msecs
> PM: early resume of devices complete after 0.204 msecs
> PM: resume of devices complete after 0.308 msecs
> Restarting tasks ... 
> 
> renesas_usbhs renesas_usbhs.1: USB Host Controller
> renesas_usbhs renesas_usbhs.1: new USB bus registered, assigned bus number 1
> done.
> hub 1-0:1.0: USB hub found
> hub 1-0:1.0: 1 port detected
> asoc-simple-card asoc-simple-card.0: ASoC: CODEC DAI ak4642-hifi not registered
> platform asoc-simple-card.0: Driver asoc-simple-card requests probe deferral
> 
> 
> > Thanks!
> 
> Any time.