[PATCH 08/17] powerpc/85xx: add support to JOG feature using cpufreq interface

[Zhao Chenhui]

On Sun, Apr 07, 2013 at 10:30:41AM +0800, Tang Yuantian-B29983 wrote:
> Also send this patch to cpufreq at vger.kernel.org and linux-pm at vger.kernel.org
> And better to rebase it on git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git
> 
> Thanks,
> Yuantian

OK. Thanks.

-Chenhui

> 
> > -----Original Message-----
> > From: Linuxppc-dev [mailto:linuxppc-dev-
> > bounces+b29983=freescale.com at lists.ozlabs.org] On Behalf Of Zhao Chenhui
> > Sent: 2013年4月3日 21:09
> > To: linuxppc-dev at lists.ozlabs.org
> > Subject: [PATCH 08/17] powerpc/85xx: add support to JOG feature using
> > cpufreq interface
> > 
> > From: chenhui zhao <chenhui.zhao at freescale.com>
> > 
> > Some MPC85xx SoCs 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 flag 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 <daveliu at freescale.com>
> > Signed-off-by: Li Yang <leoli at freescale.com>
> > Signed-off-by: Jerry Huang <Chang-Ming.Huang at freescale.com>
> > Signed-off-by: Zhao Chenhui <chenhui.zhao at freescale.com>