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msm: kgsl: convert timestamp_cmp logic to use unsigned logic

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The meaning of timestamps becomes difficult to understand when
converting between unsigned and signed values. Values that
were seperated by 0x80000000 also returned inconsistent
results.

CRs-Fixed: 355752
Change-Id: I91c904208cbfb8828766c46b736130d23022b42b
Signed-off-by: Jeff Boody <jboody@codeaurora.org>
This commit is contained in:
Jeff Boody
2012-04-24 14:57:45 -06:00
parent 868a078627
commit 23bfaa2f30
1 changed files with 16 additions and 6 deletions
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22
drivers/gpu/msm/kgsl.h
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@@ -33,7 +33,7 @@
#define KGSL_MEMSTORE_MAX (KGSL_MEMSTORE_SIZE / \
sizeof(struct kgsl_devmemstore) - 1)
/* Timestamp window used to detect rollovers */
/* Timestamp window used to detect rollovers (half of integer range) */
#define KGSL_TIMESTAMP_WINDOW 0x80000000
/*cache coherency ops */
@@ -229,14 +229,24 @@ static inline uint8_t *kgsl_gpuaddr_to_vaddr(struct kgsl_memdesc *memdesc,
return hostptr != NULL ? hostptr + (gpuaddr - memdesc->gpuaddr) : NULL;
}
static inline int timestamp_cmp(unsigned int new, unsigned int old)
static inline int timestamp_cmp(unsigned int a, unsigned int b)
{
int ts_diff = new - old;
if (ts_diff == 0)
/* check for equal */
if (a == b)
return 0;
return ((ts_diff > 0) || (ts_diff < -KGSL_TIMESTAMP_WINDOW)) ? 1 : -1;
/* check for greater-than for non-rollover case */
if ((a > b) && (a - b < KGSL_TIMESTAMP_WINDOW))
return 1;
/* check for greater-than for rollover case
* note that <= is required to ensure that consistent
* results are returned for values whose difference is
* equal to the window size
*/
a += KGSL_TIMESTAMP_WINDOW;
b += KGSL_TIMESTAMP_WINDOW;
return ((a > b) && (a - b <= KGSL_TIMESTAMP_WINDOW)) ? 1 : -1;
}
static inline void