ARM V7 (OMAP): add data cache support, test on Beagle board

Add data cache support for ARM V7 systems. Used cache flush
functions from linux:arch/arm/mm/cache-v7.S developed from
Catalin Marinas.

Enable "cache" command on Beagle board and test performance.

    Test 1: Loading 127 MB of data from NAND flash into RAM:

    Instr. Cache	off	on	on
      Data Cache	off	off	on
    --------------------------------------------------
    Beagle (Cortex A8)	116s	106s	30.3s	= x 3.8

    Test 2: uncompressing a gzipped image from RAM to RAM
            (size compressed: 6.5 MiB, uncompressed: 35 MiB):

    Instr. Cache	off	on	on
      Data Cache	off	off	on
    --------------------------------------------------
    Beagle (Cortex A8)	1.84s	1.64s	0.12s	= x 15.3

Portions of this work were supported by funding from
the CE Linux Forum.

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Ben Gardiner<bengardiner@nanometrics.ca>

2 files changed, 85 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/omap3/cache.S b/arch/arm/cpu/armv7/omap3/cache.S
index fdc1666..cda87ba 100644
--- a/arch/arm/cpu/armv7/omap3/cache.S
+++ b/arch/arm/cpu/armv7/omap3/cache.S
@@ -181,3 +181,83 @@ setup_auxcr:
 	orrlt	r0, r0, #1 << 27
 	.word 0xE1600070			@ SMC
 	bx	lr
+
+.align 5
+.global v7_flush_dcache_all
+.global v7_flush_cache_all
+
+/*
+ *	v7_flush_dcache_all()
+ *
+ *	Flush the whole D-cache.
+ *
+ *	Corrupted registers: r0-r7, r9-r11 (r6 only in Thumb mode)
+ *
+ *	- mm    - mm_struct describing address space
+ */
+v7_flush_dcache_all:
+#	dmb					@ ensure ordering with previous memory accesses
+	mrc	p15, 1, r0, c0, c0, 1		@ read clidr
+	ands	r3, r0, #0x7000000		@ extract loc from clidr
+	mov	r3, r3, lsr #23			@ left align loc bit field
+	beq	finished			@ if loc is 0, then no need to clean
+	mov	r10, #0				@ start clean at cache level 0
+loop1:
+	add	r2, r10, r10, lsr #1		@ work out 3x current cache level
+	mov	r1, r0, lsr r2			@ extract cache type bits from clidr
+	and	r1, r1, #7			@ mask of the bits for current cache only
+	cmp	r1, #2				@ see what cache we have at this level
+	blt	skip				@ skip if no cache, or just i-cache
+	mcr	p15, 2, r10, c0, c0, 0		@ select current cache level in cssr
+	mcr	p15, 0, r10, c7, c5, 4		@ flush prefetch buffer,
+						@ with armv7 this is 'isb',
+						@ but we compile with armv5
+	mrc	p15, 1, r1, c0, c0, 0		@ read the new csidr
+	and	r2, r1, #7			@ extract the length of the cache lines
+	add	r2, r2, #4			@ add 4 (line length offset)
+	ldr	r4, =0x3ff
+	ands	r4, r4, r1, lsr #3		@ find maximum number on the way size
+	clz	r5, r4				@ find bit position of way size increment
+	ldr	r7, =0x7fff
+	ands	r7, r7, r1, lsr #13		@ extract max number of the index size
+loop2:
+	mov	r9, r4				@ create working copy of max way size
+loop3:
+	orr	r11, r10, r9, lsl r5		@ factor way and cache number into r11
+	orr	r11, r11, r7, lsl r2		@ factor index number into r11
+	mcr	p15, 0, r11, c7, c14, 2		@ clean & invalidate by set/way
+	subs	r9, r9, #1			@ decrement the way
+	bge	loop3
+	subs	r7, r7, #1			@ decrement the index
+	bge	loop2
+skip:
+	add	r10, r10, #2			@ increment cache number
+	cmp	r3, r10
+	bgt	loop1
+finished:
+	mov	r10, #0				@ swith back to cache level 0
+	mcr	p15, 2, r10, c0, c0, 0		@ select current cache level in cssr
+#	dsb
+	mcr	p15, 0, r10, c7, c5, 4		@ flush prefetch buffer,
+						@ with armv7 this is 'isb',
+						@ but we compile with armv5
+	mov	pc, lr
+
+/*
+ *	v7_flush_cache_all()
+ *
+ *	Flush the entire cache system.
+ *  The data cache flush is now achieved using atomic clean / invalidates
+ *  working outwards from L1 cache. This is done using Set/Way based cache
+ *  maintainance instructions.
+ *  The instruction cache can still be invalidated back to the point of
+ *  unification in a single instruction.
+ *
+ */
+v7_flush_cache_all:
+	stmfd	sp!, {r0-r7, r9-r11, lr}
+	bl	v7_flush_dcache_all
+	mov	r0, #0
+	mcr	p15, 0, r0, c7, c5, 0		@ I+BTB cache invalidate
+	ldmfd	sp!, {r0-r7, r9-r11, lr}
+	mov	pc, lr
diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
index b36fd24..3684cad 100644
--- a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ -38,5 +38,10 @@ void  flush_cache (unsigned long dummy1, unsigned long dummy2)
 	/* disable write buffer as well (page 2-22) */
 	asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
 #endif
+#ifdef CONFIG_ARMCORTEXA8
+	void v7_flush_cache_all(void);
+
+	v7_flush_cache_all();
+#endif
 	return;
 }