| Message ID | BANLkTinsZ2hqBvVnrJBe2EQR+kLD1AuuDQ@mail.gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Kevin Hilman |
| Headers | show |
"Menon, Nishanth" <nm@ti.com> writes: > On Wed, Jun 8, 2011 at 13:51, Kevin Hilman <khilman@ti.com> wrote: > [..] >>> the issue is as follows: >>> currently we dont do voltage transitions. when we do that >>> eventually(and my current code has an forked implementation of dvfs, >>> the following steps happen): >>> late_initcall(omap2_common_pm_late_init); >>> does pmic inits, omap_voltage_late_init, init_voltages and SR dev initialization >>> >>> without these, there is no way to transition MPU to proper voltage, >>> frequency combination. The requirement will have to be that >>> omap2-cpufreq.c allows for cpufreq transitions only after voltage and >>> clk layers are ready for transitions - if we ever want to do dvfs - >>> which we will eventually need to. >> >> Yes, I understand. >> >> But $SUBJECT patch is fixing this as an _init_ time ordering problem, >> What you're describing is a runtime requirement that doesn't exist until >> a DVFS transition is done. IOW, the requirement is that the voltage >> etc. layers have to be init'd before the first transition. >> >> So, rather than fix this with initcall ordering (which will have to be >> redone as things git moved and converted to modules), just create a type >> of late init function in this driver, which gets called on the first >> transition. > > The tricky part ofcourse is for the registration - if we do the > registration, omap_cpu_init will get called once the registration > happens - no reason to stop it, which in turn triggers omap_target the > moment the governors are ready to do their thing. Yes. > Is the following what you are talking about? I am not completely sure > how this helps.. No. I was thinking of doing registration as it is today, but have a late hook that is called in the driver's->target() callback that checks if the other frameworks are ready. But now I see now that ->target() is called right after ->init(), so I don't think this helps. Sheesh. The PM init sequence/dependencies right now are a complete mess. Probably a better solution to this, would be to actually create a platform driver out of our CPUfreq driver. Then, PM core late init would just register the platform device when it's ready. This would also work if/when the CPUfreq driver is a module. Kevin > diff --git a/arch/arm/mach-omap2/omap2plus-cpufreq.c > b/arch/arm/mach-omap2/omap2plus-cpufreq.c > index 77efcb0..8586df8 100644 > --- a/arch/arm/mach-omap2/omap2plus-cpufreq.c > +++ b/arch/arm/mach-omap2/omap2plus-cpufreq.c > @@ -253,6 +253,11 @@ static struct cpufreq_driver omap_driver = { > .attr = omap_cpufreq_attr, > }; > > +static int __init omap_cpufreq_lateinit(void) > +{ > + return cpufreq_register_driver(&omap_driver); > +} > + > static int __init omap_cpufreq_init(void) > { > if (cpu_is_omap24xx()) { > @@ -277,8 +282,7 @@ static int __init omap_cpufreq_init(void) > pr_warning("%s: unable to get the mpu device\n", __func__); > return -EINVAL; > } > - > - return cpufreq_register_driver(&omap_driver); > + return 0; > } > > static void __exit omap_cpufreq_exit(void) > @@ -288,5 +292,6 @@ static void __exit omap_cpufreq_exit(void) > > MODULE_DESCRIPTION("cpufreq driver for OMAP2PLUS SOCs"); > MODULE_LICENSE("GPL"); > +late_initcall(omap_cpufreq_lateinit); > module_init(omap_cpufreq_init); > module_exit(omap_cpufreq_exit); > > > Regards, > Nishanth Menon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/mach-omap2/omap2plus-cpufreq.c b/arch/arm/mach-omap2/omap2plus-cpufreq.c index 77efcb0..8586df8 100644 --- a/arch/arm/mach-omap2/omap2plus-cpufreq.c +++ b/arch/arm/mach-omap2/omap2plus-cpufreq.c @@ -253,6 +253,11 @@ static struct cpufreq_driver omap_driver = { .attr = omap_cpufreq_attr, }; +static int __init omap_cpufreq_lateinit(void) +{ + return cpufreq_register_driver(&omap_driver); +} + static int __init omap_cpufreq_init(void) { if (cpu_is_omap24xx()) { @@ -277,8 +282,7 @@ static int __init omap_cpufreq_init(void) pr_warning("%s: unable to get the mpu device\n", __func__); return -EINVAL; } - - return cpufreq_register_driver(&omap_driver); + return 0; } static void __exit omap_cpufreq_exit(void) @@ -288,5 +292,6 @@ static void __exit omap_cpufreq_exit(void) MODULE_DESCRIPTION("cpufreq driver for OMAP2PLUS SOCs"); MODULE_LICENSE("GPL"); +late_initcall(omap_cpufreq_lateinit); module_init(omap_cpufreq_init); module_exit(omap_cpufreq_exit);