Messages in this thread | | | From | "Shilimkar, Santosh" <> | Date | Wed, 12 Sep 2012 13:13:33 +0530 | Subject | Re: [PATCH] ARM: suspend: use flush range instead of flush all |
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+ Lorenzo,
On Wed, Sep 12, 2012 at 12:48 PM, wzch <wzch@marvell.com> wrote: > From: Wenzeng Chen <wzch@marvell.com> > > In cpu suspend function __cpu_suspend_save(), we save cp15 registers, > resume function, sp and suspend_pgd, then flush the data to DDR, but > no need to flush all D cache, only need to flush range. > > Change-Id: I591a1fde929f3f987c69306b601843ed975d3e41 You should drop above.
> Signed-off-by: Wenzeng Chen <wzch@marvell.com> > --- Lorenzo and myself discussed about the above expensive flush and he is planning to post a similar patch but with small difference.
> arch/arm/kernel/suspend.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c > index 1794cc3..bb582d8 100644 > --- a/arch/arm/kernel/suspend.c > +++ b/arch/arm/kernel/suspend.c > @@ -17,6 +17,7 @@ extern void cpu_resume_mmu(void); > */ > void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr) > { > + u32 *ptr_orig = ptr; > *save_ptr = virt_to_phys(ptr); > > /* This must correspond to the LDM in cpu_resume() assembly */ > @@ -26,7 +27,8 @@ void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr) > > cpu_do_suspend(ptr); > > - flush_cache_all(); Lorenzo's patch was limiting above flush to local cache (LOUs) instead of dropping it completely.
> + __cpuc_flush_dcache_area((void *)ptr_orig, ptrsz); > + __cpuc_flush_dcache_area((void *)save_ptr, sizeof(*save_ptr)); > outer_clean_range(*save_ptr, *save_ptr + ptrsz); > outer_clean_range(virt_to_phys(save_ptr), > virt_to_phys(save_ptr) + sizeof(*save_ptr));
Just thinking bit more, even in case we drop the flush_cache_all() completely, it should be safe since the suspend_finisher() takes care of the cache maintenance already.
Regards Santosh
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