On Tuesday, October 06, 2015 at 10:21:48 AM, Thomas Chou wrote:
Set default icache and dcache configuration for start.S. The values are chosen so that it will work for most configurations. During initialization, cpu information will be extracted from device tree. Then cache flush operations will have correct cache configurations.
Signed-off-by: Thomas Chou thomas@wytron.com.tw
arch/nios2/cpu/start.S | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/arch/nios2/cpu/start.S b/arch/nios2/cpu/start.S index 00cec40..83d1576 100644 --- a/arch/nios2/cpu/start.S +++ b/arch/nios2/cpu/start.S @@ -9,6 +9,15 @@ #include <config.h> #include <version.h>
+/*
- icache and dcache configuration used only for start.S.
- the values are chosen so that it will work for all configuration.
- */
+#define ICACHE_LINE_SIZE 32 /* fixed 32 */ +#define ICACHE_SIZE_MAX 0x10000 /* 64k max */ +#define DCACHE_LINE_SIZE_MIN 4 /* 4, 16, 32 */ +#define DCACHE_SIZE_MAX 0x10000 /* 64k max */
/*************************************************************************
- RESTART
************************************************************************/ @@ -25,9 +34,9 @@ _start: * just be invalidating the cache a second time. If cache * is not implemented initi behaves as nop. */
- ori r4, r0, %lo(CONFIG_SYS_ICACHELINE_SIZE)
- movhi r5, %hi(CONFIG_SYS_ICACHE_SIZE)
- ori r5, r5, %lo(CONFIG_SYS_ICACHE_SIZE)
- ori r4, r0, %lo(ICACHE_LINE_SIZE)
- movhi r5, %hi(ICACHE_SIZE_MAX)
- ori r5, r5, %lo(ICACHE_SIZE_MAX)
0: initi r5 sub r5, r5, r4 bgt r5, r0, 0b @@ -54,10 +63,9 @@ _except_end: * DCACHE INIT -- if dcache not implemented, initd behaves as * nop. */
- movhi r4, %hi(CONFIG_SYS_DCACHELINE_SIZE)
- ori r4, r4, %lo(CONFIG_SYS_DCACHELINE_SIZE)
- movhi r5, %hi(CONFIG_SYS_DCACHE_SIZE)
- ori r5, r5, %lo(CONFIG_SYS_DCACHE_SIZE)
- ori r4, r0, %lo(DCACHE_LINE_SIZE_MIN)
- movhi r5, %hi(DCACHE_SIZE_MAX)
- ori r5, r5, %lo(DCACHE_SIZE_MAX) mov r6, r0
1: initd 0(r6) add r6, r6, r4
Did I miss the DT part somewhere or is that not part of this patch ?
Another question I have is -- why don't we set CONFIG_SYS_{I,D}CACHE_SIZE to maximum value? This should work for all nios2 cache configurations and it should also be correct, no ? Speed might be a bit of an issue here, but I doubt the impact would be that large.
Best regards, Marek Vasut