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Blackfin: SIC: cut down on IAR MMR reads a bit

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Tweak the for loops that operate on the SIC IAR system MMRs to avoid
re-reading them multiple times in a row.  System MMRs are a little
slower to access, so avoid the penalty when possible.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Mike Frysinger 2010-04-22 21:15:00 +00:00
parent 11cabcb95e
commit 80fcdb9593
1 changed files with 18 additions and 15 deletions
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33
arch/blackfin/mach-common/ints-priority.c
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@ -92,26 +92,29 @@ static void __init search_IAR(void)
{
unsigned ivg, irq_pos = 0;
for (ivg = 0; ivg <= IVG13 - IVG7; ivg++) {
int irqn;
int irqN;
ivg7_13[ivg].istop = ivg7_13[ivg].ifirst = &ivg_table[irq_pos];
for (irqn = 0; irqn < NR_PERI_INTS; irqn++) {
int iar_shift = (irqn & 7) * 4;
if (ivg == (0xf &
#if defined(CONFIG_BF52x) || defined(CONFIG_BF538) \
|| defined(CONFIG_BF539) || defined(CONFIG_BF51x)
bfin_read32((unsigned long *)SIC_IAR0 +
((irqn % 32) >> 3) + ((irqn / 32) *
((SIC_IAR4 - SIC_IAR0) / 4))) >> iar_shift)) {
for (irqN = 0; irqN < NR_PERI_INTS; irqN += 4) {
int irqn;
u32 iar = bfin_read32((unsigned long *)SIC_IAR0 +
#if defined(CONFIG_BF51x) || defined(CONFIG_BF52x) || \
defined(CONFIG_BF538) || defined(CONFIG_BF539)
((irqN % 32) >> 3) + ((irqN / 32) * ((SIC_IAR4 - SIC_IAR0) / 4))
#else
bfin_read32((unsigned long *)SIC_IAR0 +
(irqn >> 3)) >> iar_shift)) {
(irqN >> 3)
#endif
ivg_table[irq_pos].irqno = IVG7 + irqn;
ivg_table[irq_pos].isrflag = 1 << (irqn % 32);
ivg7_13[ivg].istop++;
irq_pos++;
);
for (irqn = irqN; irqn < irqN + 4; ++irqn) {
int iar_shift = (irqn & 7) * 4;
if (ivg == (0xf & (iar >> iar_shift))) {
ivg_table[irq_pos].irqno = IVG7 + irqn;
ivg_table[irq_pos].isrflag = 1 << (irqn % 32);
ivg7_13[ivg].istop++;
irq_pos++;
}
}
}
}