ARM (ARM11): add data cache support, test on Qong board

Add data cache support for arm1136 systems.

Enable "cache" command on Qong 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
    --------------------------------------------------
    QONG (ARM11)	177s	95s	43s	= x 4.1

    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
    --------------------------------------------------
    QONG (ARM11)	1.54s	0.95s	0.18s	= x 8.6

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

Signed-off-by: Heiko Schocher <hs@denx.de>

arch/arm/cpu/arm1136/start.S

@@ -439,6 +439,11 @@ fiq:
 	.align 5
 .global arm1136_cache_flush
 arm1136_cache_flush:
+#if !defined(CONFIG_SYS_NO_ICACHE)
 		mcr	p15, 0, r1, c7, c5, 0	@ invalidate I cache
+#endif
+#if !defined(CONFIG_SYS_NO_DCACHE)
+		mcr	p15, 0, r1, c7, c14, 0	@ invalidate D cache
+#endif
 		mov	pc, lr			@ back to caller
 #endif	/* CONFIG_PRELOADER */

arch/arm/lib/cache.c

@@ -27,7 +27,7 @@
 
 void  flush_cache (unsigned long dummy1, unsigned long dummy2)
 {
-#ifdef CONFIG_OMAP2420
+#if defined(CONFIG_OMAP2420) || defined(CONFIG_ARM1136)
 	void arm1136_cache_flush(void);
 
 	arm1136_cache_flush();

include/configs/qong.h

@@ -104,6 +104,7 @@
 
 #include <config_cmd_default.h>
 
+#define CONFIG_CMD_CACHE
 #define CONFIG_CMD_PING
 #define CONFIG_CMD_DHCP
 #define CONFIG_CMD_NET