ARM (ARM926ejs): add data cache support, tested on magnesium and tx25 board
Enable "cache" command on tx25 and magnesium 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
--------------------------------------------------
magnesium 32,6s 22,5s 30s = x 1,09
tx25 (29MB only) 9,69s 5,05s 8,16s = x 1,19
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
--------------------------------------------------
magnesium 4,25s 2,08s 1,72s = x 2,47
tx25 4,82s 2,04s 1,84s = x 2,62
Portions of this work were supported by funding from
the CE Linux Forum.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Alessandro Rubini <rubini@gnudd.com>
diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
index 61ee9d3..b36fd24 100644
--- a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ -32,5 +32,11 @@
arm1136_cache_flush();
#endif
+#ifdef CONFIG_ARM926EJS
+ /* test and clean, page 2-23 of arm926ejs manual */
+ asm("0: mrc p15, 0, r15, c7, c10, 3\n\t" "bne 0b\n" : : : "memory");
+ /* disable write buffer as well (page 2-22) */
+ asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
+#endif
return;
}