On Jul 20, 2012, at 7:42 AM, Zhao Chenhui wrote:
> Some 85xx silicons like MPC8536 and P1022 have a JOG feature, which provides
> a dynamic mechanism to lower or raise the CPU core clock at runtime.
>
> This patch adds the support to change CPU frequency using the standard
> cpufreq interface. The ratio CORE to CCB can be 1:1(except MPC8536), 3:2,
> 2:1, 5:2, 3:1, 7:2 and 4:1.
>
> Two CPU cores on P1022 must not in the low power state during the frequency
> transition. The driver uses a atomic counter to meet the requirement.
>
> The jog mode frequency transition process on the MPC8536 is similar to
> the deep sleep process. The driver need save the CPU state and restore
> it after CPU warm reset.
>
> Note:
> * The I/O peripherals such as PCIe and eTSEC may lose packets during
> the jog mode frequency transition.
> * The driver doesn't support MPC8536 Rev 1.0 due to a JOG erratum.
> Subsequent revisions of MPC8536 have corrected the erratum.
>
> Signed-off-by: Dave Liu <dave...@freescale.com>
> Signed-off-by: Li Yang <le...@freescale.com>
> Signed-off-by: Jerry Huang <chang-ming.hu...@freescale.com>
> Signed-off-by: Zhao Chenhui <chenhui.z...@freescale.com>
> CC: Scott Wood <scottw...@freescale.com>
> ---
> arch/powerpc/platforms/85xx/Makefile | 1 +
> arch/powerpc/platforms/85xx/cpufreq-jog.c | 388 +++++++++++++++++++++++++++++
> arch/powerpc/platforms/Kconfig | 11 +
> arch/powerpc/sysdev/fsl_pmc.c | 3 +
> arch/powerpc/sysdev/fsl_soc.h | 2 +
> include/linux/cpu.h | 4 +
> 6 files changed, 409 insertions(+), 0 deletions(-)
> create mode 100644 arch/powerpc/platforms/85xx/cpufreq-jog.c
[snip]
> diff --git a/include/linux/cpu.h b/include/linux/cpu.h
> index 2e9b9eb..c1ba260 100644
> --- a/include/linux/cpu.h
> +++ b/include/linux/cpu.h
> @@ -145,6 +145,8 @@ void notify_cpu_starting(unsigned int cpu);
> extern void cpu_maps_update_begin(void);
> extern void cpu_maps_update_done(void);
>
> +extern void cpu_hotplug_disable_before_freeze(void);
> +extern void cpu_hotplug_enable_after_thaw(void);
> #else /* CONFIG_SMP */
>
> #define cpu_notifier(fn, pri) do { (void)(fn); } while (0)
> @@ -166,6 +168,8 @@ static inline void cpu_maps_update_done(void)
> {
> }
>
> +static inline void cpu_hotplug_disable_before_freeze(void) {}
> +static inline void cpu_hotplug_enable_after_thaw(void) {}
> #endif /* CONFIG_SMP */
> extern struct bus_type cpu_subsys;
Can you pull this change into a separate patch. I want an ACK by Rafael J.
Wysocki on it.
- k--
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