On Fri, Jul 08, 2011 at 03:14:02AM +0100, Santosh Shilimkar wrote: > On 7/7/2011 8:50 AM, Lorenzo Pieralisi wrote: > > When a CLUSTER is powered down the SCU must be reinitialized on > > warm-boot. > > This patch adds a hook to reset the SCU, which implies invalidating > > TAG RAMs and renabling it. > > > > The scu virtual address is saved in a static variable when the SCU > > is first enabled at boot; this allows common idle code to be > > generic and avoid relying on platform code to get the address at > > run-time. > > On warm-boot the SCU TAG RAM is invalidated and the SCU enabled if > > it is not already enabled. > > > > The reset can be skipped altogether thanks to save/restore > > framework flags. > > > > Flushing D$ cache is cumbersome since the system just comes out of > > reset, which invalidates caches in the process if needed (A9), that > > is why the scu_enable function is not reused as it is to reset the SCU. > > > > If the init function is extended, there might not be a need for > > a SCU specific hook, since the init function can be reused to > > reinitialize the SCU at boot provided it is removed from the init > > section and kept in memory. > > > > Signed-off-by: Lorenzo Pieralisi<lorenzo.pieral...@arm.com> > > --- > > arch/arm/include/asm/smp_scu.h | 3 ++- > > arch/arm/kernel/smp_scu.c | 33 ++++++++++++++++++++++++++++++--- > > 2 files changed, 32 insertions(+), 4 deletions(-) > > > > diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h > > index 4eb6d00..cfaa68e 100644 > > --- a/arch/arm/include/asm/smp_scu.h > > +++ b/arch/arm/include/asm/smp_scu.h > > @@ -8,7 +8,8 @@ > > #ifndef __ASSEMBLER__ > > unsigned int scu_get_core_count(void __iomem *); > > void scu_enable(void __iomem *); > > -int scu_power_mode(void __iomem *, unsigned int); > > +int scu_power_mode(unsigned int); > > +void scu_reset(void); > > #endif > > > > #endif > > diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c > > index a1e757c..980ced9 100644 > > --- a/arch/arm/kernel/smp_scu.c > > +++ b/arch/arm/kernel/smp_scu.c > > @@ -20,6 +20,7 @@ > > #define SCU_INVALIDATE 0x0c > > #define SCU_FPGA_REVISION 0x10 > > > > +static void __iomem *scu_va; > > Change log and patch doesn't seems to match. I remember suggesting > this change to Russell when "scu_power_mode()" was introduced. > His preference was to have scu_base passed as part of the API.
Yes, but this implies that I have to call into platform code to get the SCU virtual address. The change log seems ok to me, maybe I have not explained properly the end goal. I would like to reuse scu_enable when the cluster wakes up from low-power instead of adding a reset hook, but invalidating caches (flush_cache_all() in scu_enable) is already catered for in the reset path, so useless. I will work that out. I also added an assembly function to programme the SCU power mode (PATCH 07/17 of this series), since it has to be called from MMU off path. Lorenzo _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
