i8259: Fix poll command

This was probably never used so far: According to the spec, polling
means ack'ing the pending IRQ and setting its corresponding bit in isr.
Moreover, we have to signal a pending IRQ via bit 7 of the returned
value, and we must not return a spurious IRQ if none is pending.

This implements the poll command without the help of pic_poll_read which
is left untouched as pic_intack_read is still using it.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This commit is contained in:
Jan Kiszka 2011-10-07 09:19:47 +02:00 committed by Blue Swirl
parent b76750c1ab
commit 8d484caa84

View File

@ -393,7 +393,13 @@ static uint64_t pic_ioport_read(void *opaque, target_phys_addr_t addr1,
int ret;
if (s->poll) {
ret = pic_poll_read(s);
ret = pic_get_irq(s);
if (ret >= 0) {
pic_intack(s, ret);
ret |= 0x80;
} else {
ret = 0;
}
s->poll = 0;
} else {
if (addr == 0) {