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[PARISC] Fix parisc_setup_cache_timing to choose a better flush threshold

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update comment about CAFL_STRIDE

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

Fixed a bug in parisc_setup_cache_timing() which caused it to calculate
a poor value for parisc_cache_flush_threshold.

Thanks to Joel Soete for spotting the bug.
Thanks to James Bottomley for pointing out the clean way to fix this.

Signed-off-by: Stuart Brady <sdb@parisc-linux.org>

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This commit is contained in:
Stuart Brady 2005-10-21 22:44:14 -04:00 committed by Kyle McMartin
parent f053725b89
commit 2464212f68
1 changed files with 6 additions and 4 deletions
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10
arch/parisc/kernel/cache.c
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@ -27,6 +27,7 @@
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/sections.h>
int split_tlb;
int dcache_stride;
@ -207,6 +208,9 @@ parisc_cache_init(void)
/* "New and Improved" version from Jim Hull
* (1 << (cc_block-1)) * (cc_line << (4 + cnf.cc_shift))
* The following CAFL_STRIDE is an optimized version, see
* http://lists.parisc-linux.org/pipermail/parisc-linux/2004-June/023625.html
* http://lists.parisc-linux.org/pipermail/parisc-linux/2004-June/023671.html
*/
#define CAFL_STRIDE(cnf) (cnf.cc_line << (3 + cnf.cc_block + cnf.cc_shift))
dcache_stride = CAFL_STRIDE(cache_info.dc_conf);
@ -339,17 +343,15 @@ int parisc_cache_flush_threshold = FLUSH_THRESHOLD;
void parisc_setup_cache_timing(void)
{
unsigned long rangetime, alltime;
extern char _text; /* start of kernel code, defined by linker */
extern char _end; /* end of BSS, defined by linker */
unsigned long size;
alltime = mfctl(16);
flush_data_cache();
alltime = mfctl(16) - alltime;
size = (unsigned long)(&_end - _text);
size = (unsigned long)(_end - _text);
rangetime = mfctl(16);
flush_kernel_dcache_range((unsigned long)&_text, size);
flush_kernel_dcache_range((unsigned long)_text, size);
rangetime = mfctl(16) - rangetime;
printk(KERN_DEBUG "Whole cache flush %lu cycles, flushing %lu bytes %lu cycles\n",