> -----Original Message----- > From: Wood Scott-B07421 > Sent: Tuesday, July 30, 2013 1:27 AM > To: Wang Dongsheng-B40534 > Cc: b...@kernel.crashing.org; ga...@kernel.crashing.org; Zhao Chenhui- > B35336; Li Yang-R58472; Wang Dongsheng-B40534 > Subject: Re: [RFC 2/2] powerpc/cputable: add wait feature for CPU kernel > features > > On 07/10/2013 03:27:56 AM, Dongsheng Wang wrote: > > From: Wang Dongsheng <dongsheng.w...@freescale.com> > > > > Signed-off-by: Wang Dongsheng <dongsheng.w...@freescale.com> > > > > diff --git a/arch/powerpc/include/asm/cputable.h > > b/arch/powerpc/include/asm/cputable.h > > index 6f3887d..0a8d0cb 100644 > > --- a/arch/powerpc/include/asm/cputable.h > > +++ b/arch/powerpc/include/asm/cputable.h > > @@ -138,6 +138,7 @@ extern const char *powerpc_base_platform; > > #define CPU_FTR_NOEXECUTE ASM_CONST(0x10000000) > > #define CPU_FTR_INDEXED_DCR ASM_CONST(0x20000000) > > #define CPU_FTR_EMB_HV ASM_CONST(0x40000000) > > +#define CPU_FTR_CAN_WAIT ASM_CONST(0x80000000) > > Note that this is the last 32-bit CPU feature flag; it's time to start > thinking about other mechanisms. We should probably reserve feature > flags for things that need to use code patching due to being on a > performance critical path, and move other things into struct cpu_spec. > CPU_FTR_CAN_WAIT seems like a good candidate to be moved. > First of all, why should I do, I need to distinguish between the core, which is to support the wait instruction. The CPU_FTR_CAN_WAIT looks easy.
How to fix this problem: 1/ I can drop this cpu feature, and move it into struct cpu_spec. Add a pm_feature in struct cpu_spec? like, struct cpu_spec { ... unsigned long pm_features; ... } 2/ Drop this cpu feature, using CPU_FTRS_E6500/CPU_FTRS_E5500.. to distinguish wait or doze/nap. Like, CPU_FTRS_E500/CPU_FTRS_E500_2 support doze/nap. CPU_FTRS_E500MC/CPU_FTRS_E5500/CPU_FTRS_E6500 support wait. If using this method, inside the cpuidle driver needs to do a lot of judgment. So I'm not sure this is a very good solution. Thanks. - dongsheng _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev