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Staging: et131x: Correct WRAP bit handling

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add_10bit loses the existing wrap value

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox
2009-10-12 15:38:17 +01:00
committed by Greg Kroah-Hartman
parent 4439c93535
commit b9d2dde055
1 changed files with 14 additions and 6 deletions
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14
drivers/staging/et131x/et1310_rx.c
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@@ -1178,9 +1178,17 @@ void et131x_handle_recv_interrupt(struct et131x_adapter *etdev)
static inline u32 bump_fbr(u32 *fbr, u32 limit) static inline u32 bump_fbr(u32 *fbr, u32 limit)
{ {
u32 v = *fbr; u32 v = *fbr;
add_10bit(&v, 1); v++;
if (v > limit) /* This works for all cases where limit < 1024. The 1023 case
v = (*fbr & ~ET_DMA10_MASK) ^ ET_DMA10_WRAP; works because 1023++ is 1024 which means the if condition is not
taken but the carry of the bit into the wrap bit toggles the wrap
value correctly */
if ((v & ET_DMA10_MASK) > limit) {
v &= ~ET_DMA10_MASK;
v ^= ET_DMA10_WRAP;
}
/* For the 1023 case */
v &= (ET_DMA10_MASK|ET_DMA10_WRAP);
*fbr = v; *fbr = v;
return v; return v;
} }