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author | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2012-09-06 15:05:13 +0200 |
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committer | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2012-09-25 12:20:25 +0200 |
commit | 031bd879f79d59d2f4fccd44377adf24fb977b5a (patch) | |
tree | b9a6e72de46ada3ab0b96287f11bc4205874e98f /arch/arm/mm/cache-v7.S | |
parent | Linux 3.6-rc6 (diff) | |
download | linux-031bd879f79d59d2f4fccd44377adf24fb977b5a.tar.xz linux-031bd879f79d59d2f4fccd44377adf24fb977b5a.zip |
ARM: mm: implement LoUIS API for cache maintenance ops
ARM v7 architecture introduced the concept of cache levels and related
control registers. New processors like A7 and A15 embed an L2 unified cache
controller that becomes part of the cache level hierarchy. Some operations in
the kernel like cpu_suspend and __cpu_disable do not require a flush of the
entire cache hierarchy to DRAM but just the cache levels belonging to the
Level of Unification Inner Shareable (LoUIS), which in most of ARM v7 systems
correspond to L1.
The current cache flushing API used in cpu_suspend and __cpu_disable,
flush_cache_all(), ends up flushing the whole cache hierarchy since for
v7 it cleans and invalidates all cache levels up to Level of Coherency
(LoC) which cripples system performance when used in hot paths like hotplug
and cpuidle.
Therefore a new kernel cache maintenance API must be added to cope with
latest ARM system requirements.
This patch adds flush_cache_louis() to the ARM kernel cache maintenance API.
This function cleans and invalidates all data cache levels up to the
Level of Unification Inner Shareable (LoUIS) and invalidates the instruction
cache for processors that support it (> v7).
This patch also creates an alias of the cache LoUIS function to flush_kern_all
for all processor versions prior to v7, so that the current cache flushing
behaviour is unchanged for those processors.
v7 cache maintenance code implements a cache LoUIS function that cleans and
invalidates the D-cache up to LoUIS and invalidates the I-cache, according
to the new API.
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mm/cache-v7.S')
-rw-r--r-- | arch/arm/mm/cache-v7.S | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S index 39e3fb3db801..d1fa2f66d8c0 100644 --- a/arch/arm/mm/cache-v7.S +++ b/arch/arm/mm/cache-v7.S @@ -33,6 +33,24 @@ ENTRY(v7_flush_icache_all) mov pc, lr ENDPROC(v7_flush_icache_all) + /* + * v7_flush_dcache_louis() + * + * Flush the D-cache up to the Level of Unification Inner Shareable + * + * Corrupted registers: r0-r7, r9-r11 (r6 only in Thumb mode) + */ + +ENTRY(v7_flush_dcache_louis) + dmb @ ensure ordering with previous memory accesses + mrc p15, 1, r0, c0, c0, 1 @ read clidr, r0 = clidr + ands r3, r0, #0xe00000 @ extract LoUIS from clidr + mov r3, r3, lsr #20 @ r3 = LoUIS * 2 + moveq pc, lr @ return if level == 0 + mov r10, #0 @ r10 (starting level) = 0 + b loop1 @ start flushing cache levels +ENDPROC(v7_flush_dcache_louis) + /* * v7_flush_dcache_all() * @@ -120,6 +138,24 @@ ENTRY(v7_flush_kern_cache_all) mov pc, lr ENDPROC(v7_flush_kern_cache_all) + /* + * v7_flush_kern_cache_louis(void) + * + * Flush the data cache up to Level of Unification Inner Shareable. + * Invalidate the I-cache to the point of unification. + */ +ENTRY(v7_flush_kern_cache_louis) + ARM( stmfd sp!, {r4-r5, r7, r9-r11, lr} ) + THUMB( stmfd sp!, {r4-r7, r9-r11, lr} ) + bl v7_flush_dcache_louis + mov r0, #0 + ALT_SMP(mcr p15, 0, r0, c7, c1, 0) @ invalidate I-cache inner shareable + ALT_UP(mcr p15, 0, r0, c7, c5, 0) @ I+BTB cache invalidate + ARM( ldmfd sp!, {r4-r5, r7, r9-r11, lr} ) + THUMB( ldmfd sp!, {r4-r7, r9-r11, lr} ) + mov pc, lr +ENDPROC(v7_flush_kern_cache_louis) + /* * v7_flush_cache_all() * |