[PATCH 12/12] ARM: tegra: Convert PMC to a driver

[Arnd Bergmann]

On Wednesday 16 July 2014 15:22:41 Thierry Reding wrote:
> On Wed, Jul 16, 2014 at 01:56:44PM +0200, Arnd Bergmann wrote:
> > On Friday 11 July 2014, Thierry Reding wrote:
> > > +/*
> > > + * PMC
> > > + */
> > > +enum tegra_suspend_mode {
> > > +       TEGRA_SUSPEND_NONE = 0,
> > > +       TEGRA_SUSPEND_LP2, /* CPU voltage off */
> > > +       TEGRA_SUSPEND_LP1, /* CPU voltage off, DRAM self-refresh */
> > > +       TEGRA_SUSPEND_LP0, /* CPU + core voltage off, DRAM self-refresh */
> > > +       TEGRA_MAX_SUSPEND_MODE,
> > > +};
> > > +
> > > +#ifdef CONFIG_PM_SLEEP
> > > +enum tegra_suspend_mode tegra_pmc_get_suspend_mode(void);
> > > +void tegra_pmc_set_suspend_mode(enum tegra_suspend_mode mode);
> > > +void tegra_pmc_enter_suspend_mode(enum tegra_suspend_mode mode);
> > > +
> > > +bool tegra_pmc_cpu_is_powered(int cpuid);
> > > +int tegra_pmc_cpu_power_on(int cpuid);
> > > +int tegra_pmc_cpu_remove_clamping(int cpuid);
> > > +
> > > +void tegra_pmc_restart(enum reboot_mode mode, const char *cmd);
> > > +#endif
> > > +
> > > +/*
> > 
> > This part is causing multiple build failures in the randconfig tests.
> > You can avoid them by removing the #ifdef.
> 
> How is this causing build failures? I only see them used wherever
> CONFIG_PM_SLEEP is defined.
> 
> Although I guess tegra-pmc.c could cause sparse warnings since it
> implements these functions regardless of CONFIG_PM_SLEEP, which probably
> is the bug that should be fixed.
> 
> Do you have a randconfig that I can use to reproduce this and come up
> with a fix?

I got this error (always):

/git/arm-soc/arch/arm/mach-tegra/tegra.c:165:13: error: 'tegra_pmc_restart' undeclared here (not in a function)
  .restart = tegra_pmc_restart,
             ^
make[3]: *** [arch/arm/mach-tegra/tegra.o] Error 1

when CONFIG_PM_SLEEP is disabled, and also this one when SMP is
turned on in addition:


/git/arm-soc/arch/arm/mach-tegra/platsmp.c: In function 'tegra30_boot_secondary':
/git/arm-soc/arch/arm/mach-tegra/platsmp.c:97:4: error: implicit declaration of function 'tegra_pmc_cpu_is_powered' [-Werror=implicit-function-declaration]
    if (tegra_pmc_cpu_is_powered(cpu))
    ^
/git/arm-soc/arch/arm/mach-tegra/platsmp.c:110:3: error: implicit declaration of function 'tegra_pmc_cpu_power_on' [-Werror=implicit-function-declaration]
   ret = tegra_pmc_cpu_power_on(cpu);
   ^
/git/arm-soc/arch/arm/mach-tegra/platsmp.c:129:2: error: implicit declaration of function 'tegra_pmc_cpu_remove_clamping' [-Werror=implicit-function-declaration]
  ret = tegra_pmc_cpu_remove_clamping(cpu);
  ^
cc1: some warnings being treated as errors

I applied this hack locally to work around that:

diff --git a/include/linux/tegra-soc.h b/include/linux/tegra-soc.h
index 70a612442cda..a89fe9e588ac 100644
--- a/include/linux/tegra-soc.h
+++ b/include/linux/tegra-soc.h
@@ -73,7 +73,6 @@ enum tegra_suspend_mode {
 	TEGRA_MAX_SUSPEND_MODE,
 };
 
-#ifdef CONFIG_PM_SLEEP
 enum tegra_suspend_mode tegra_pmc_get_suspend_mode(void);
 void tegra_pmc_set_suspend_mode(enum tegra_suspend_mode mode);
 void tegra_pmc_enter_suspend_mode(enum tegra_suspend_mode mode);
@@ -83,7 +82,6 @@ int tegra_pmc_cpu_power_on(int cpuid);
 int tegra_pmc_cpu_remove_clamping(int cpuid);
 
 void tegra_pmc_restart(enum reboot_mode mode, const char *cmd);
-#endif
 
 /*
  * PM

> > On a more general note, why are you adding this stuff into a global
> > header file in the first place? All users are in the same directory
> > in which the functions are defined.
> 
> That's mostly preparatory work. We'll need to move tegra-pmc.c out of
> arch/arm/mach-tegra at some point. I've proposed two patches already to
> do that, one move the driver to drivers/soc/tegra and was massively
> NAK'ed (I'm still not sure I agree) and people requested that this be
> moved into drivers/power. I then posted a 2 patch series to move power
> supply drivers into a subdirectory (drivers/power/supply) so that
> drivers in drivers/power didn't have to depend on CONFIG_POWER_SUPPLY
> for no good reason.
> 
> The latter series didn't receive any comments whatsoever in over a week,
> so in order to keep things moving forward I respun the PMC patch to do
> the conversion without moving the code out of arch/arm/mach-tegra yet.
> That way moving the driver out of arch/arm/mach-tegra will be a simple
> matter of moving and the rework will already be done. You were Cc'ed on
> the second series, so if you want to take a look (and maybe help get
> things moving) the patches are called:
> 
> 	[PATCH 0/2] Restructure driver/power and add Tegra PMC driver
> 	[PATCH 1/2] power: Move power-supply drivers to subdirectory
> 	[PATCH 2/2] ARM: tegra: Convert PMC to a driver

Ok, I'll have a look. I think when this becomes a separate driver, it
should also have its own header file, so maybe you can in the meantime
make it a local header file in mach-tegra until we have found a good
place for it.

	Arnd