![Lorenzo Pieralisi](/assets/img/avatar_default.png)
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>
250 lines
6.1 KiB
ArmAsm
250 lines
6.1 KiB
ArmAsm
/*
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* linux/arch/arm/mm/cache-fa.S
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*
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* Copyright (C) 2005 Faraday Corp.
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* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
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*
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* Based on cache-v4wb.S:
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* Copyright (C) 1997-2002 Russell king
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Processors: FA520 FA526 FA626
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*/
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#include <linux/linkage.h>
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#include <linux/init.h>
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#include <asm/memory.h>
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#include <asm/page.h>
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#include "proc-macros.S"
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/*
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* The size of one data cache line.
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*/
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#define CACHE_DLINESIZE 16
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/*
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* The total size of the data cache.
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*/
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#ifdef CONFIG_ARCH_GEMINI
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#define CACHE_DSIZE 8192
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#else
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#define CACHE_DSIZE 16384
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#endif
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/* FIXME: put optimal value here. Current one is just estimation */
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#define CACHE_DLIMIT (CACHE_DSIZE * 2)
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/*
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* flush_icache_all()
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*
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* Unconditionally clean and invalidate the entire icache.
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*/
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ENTRY(fa_flush_icache_all)
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mov r0, #0
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mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
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mov pc, lr
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ENDPROC(fa_flush_icache_all)
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/*
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* flush_user_cache_all()
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*
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* Clean and invalidate all cache entries in a particular address
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* space.
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*/
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ENTRY(fa_flush_user_cache_all)
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/* FALLTHROUGH */
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/*
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* flush_kern_cache_all()
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*
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* Clean and invalidate the entire cache.
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*/
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ENTRY(fa_flush_kern_cache_all)
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mov ip, #0
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mov r2, #VM_EXEC
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__flush_whole_cache:
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mcr p15, 0, ip, c7, c14, 0 @ clean/invalidate D cache
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tst r2, #VM_EXEC
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mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
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mcrne p15, 0, ip, c7, c5, 6 @ invalidate BTB
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mcrne p15, 0, ip, c7, c10, 4 @ drain write buffer
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mcrne p15, 0, ip, c7, c5, 4 @ prefetch flush
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mov pc, lr
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/*
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* flush_user_cache_range(start, end, flags)
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*
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* Invalidate a range of cache entries in the specified
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* address space.
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*
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* - start - start address (inclusive, page aligned)
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* - end - end address (exclusive, page aligned)
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* - flags - vma_area_struct flags describing address space
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*/
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ENTRY(fa_flush_user_cache_range)
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mov ip, #0
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sub r3, r1, r0 @ calculate total size
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cmp r3, #CACHE_DLIMIT @ total size >= limit?
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bhs __flush_whole_cache @ flush whole D cache
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1: tst r2, #VM_EXEC
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mcrne p15, 0, r0, c7, c5, 1 @ invalidate I line
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mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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tst r2, #VM_EXEC
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mcrne p15, 0, ip, c7, c5, 6 @ invalidate BTB
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mcrne p15, 0, ip, c7, c10, 4 @ data write barrier
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mcrne p15, 0, ip, c7, c5, 4 @ prefetch flush
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mov pc, lr
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/*
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* coherent_kern_range(start, end)
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*
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* Ensure coherency between the Icache and the Dcache in the
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* region described by start. If you have non-snooping
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* Harvard caches, you need to implement this function.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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ENTRY(fa_coherent_kern_range)
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/* fall through */
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/*
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* coherent_user_range(start, end)
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*
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* Ensure coherency between the Icache and the Dcache in the
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* region described by start. If you have non-snooping
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* Harvard caches, you need to implement this function.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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ENTRY(fa_coherent_user_range)
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bic r0, r0, #CACHE_DLINESIZE - 1
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1: mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
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mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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mov r0, #0
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mcr p15, 0, r0, c7, c5, 6 @ invalidate BTB
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mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
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mcr p15, 0, r0, c7, c5, 4 @ prefetch flush
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mov pc, lr
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/*
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* flush_kern_dcache_area(void *addr, size_t size)
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*
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* Ensure that the data held in the page kaddr is written back
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* to the page in question.
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*
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* - addr - kernel address
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* - size - size of region
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*/
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ENTRY(fa_flush_kern_dcache_area)
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add r1, r0, r1
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1: mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D line
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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mov r0, #0
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mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
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mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
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mov pc, lr
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/*
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* dma_inv_range(start, end)
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*
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* Invalidate (discard) the specified virtual address range.
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* May not write back any entries. If 'start' or 'end'
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* are not cache line aligned, those lines must be written
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* back.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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fa_dma_inv_range:
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tst r0, #CACHE_DLINESIZE - 1
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bic r0, r0, #CACHE_DLINESIZE - 1
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mcrne p15, 0, r0, c7, c14, 1 @ clean & invalidate D entry
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tst r1, #CACHE_DLINESIZE - 1
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bic r1, r1, #CACHE_DLINESIZE - 1
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mcrne p15, 0, r1, c7, c14, 1 @ clean & invalidate D entry
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1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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mov r0, #0
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mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
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mov pc, lr
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/*
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* dma_clean_range(start, end)
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*
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* Clean (write back) the specified virtual address range.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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fa_dma_clean_range:
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bic r0, r0, #CACHE_DLINESIZE - 1
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1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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mov r0, #0
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mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
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mov pc, lr
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/*
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* dma_flush_range(start,end)
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* - start - virtual start address of region
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* - end - virtual end address of region
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*/
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ENTRY(fa_dma_flush_range)
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bic r0, r0, #CACHE_DLINESIZE - 1
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1: mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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mov r0, #0
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mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
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mov pc, lr
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/*
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* dma_map_area(start, size, dir)
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* - start - kernel virtual start address
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* - size - size of region
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* - dir - DMA direction
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*/
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ENTRY(fa_dma_map_area)
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add r1, r1, r0
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cmp r2, #DMA_TO_DEVICE
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beq fa_dma_clean_range
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bcs fa_dma_inv_range
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b fa_dma_flush_range
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ENDPROC(fa_dma_map_area)
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/*
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* dma_unmap_area(start, size, dir)
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* - start - kernel virtual start address
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* - size - size of region
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* - dir - DMA direction
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*/
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ENTRY(fa_dma_unmap_area)
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mov pc, lr
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ENDPROC(fa_dma_unmap_area)
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.globl fa_flush_kern_cache_louis
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.equ fa_flush_kern_cache_louis, fa_flush_kern_cache_all
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__INITDATA
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@ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
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define_cache_functions fa
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