+ /*
+ * this needs to be flags&initted, not statusp, so we keep
+ * taking interrupts even after link goes down, etc.
+ * Also, we *must* clear the interrupt at some point, or we won't
+ * take it again, which can be real bad for errors, etc...
+ */
+
+ if (!(dd->ipath_flags & IPATH_INITTED)) {
+ ipath_bad_intr(dd, &unexpected);
+ ret = IRQ_NONE;
+ goto bail;
+ }
+
+ /*
+ * We try to avoid reading the interrupt status register, since
+ * that's a PIO read, and stalls the processor for up to about
+ * ~0.25 usec. The idea is that if we processed a port0 packet,
+ * we blindly clear the port 0 receive interrupt bits, and nothing
+ * else, then return. If other interrupts are pending, the chip
+ * will re-interrupt us as soon as we write the intclear register.
+ * We then won't process any more kernel packets (if not the 2nd
+ * time, then the 3rd or 4th) and we'll then handle the other
+ * interrupts. We clear the interrupts first so that we don't
+ * lose intr for later packets that arrive while we are processing.
+ */
+ oldhead = dd->ipath_port0head;
+ curtail = (u32)le64_to_cpu(*dd->ipath_hdrqtailptr);
+ if (oldhead != curtail) {
+ if (dd->ipath_flags & IPATH_GPIO_INTR) {
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
+ (u64) (1 << 2));
+ istat = port0rbits | INFINIPATH_I_GPIO;
+ }
+ else
+ istat = port0rbits;
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, istat);
+ ipath_kreceive(dd);
+ if (oldhead != dd->ipath_port0head) {
+ ipath_stats.sps_fastrcvint++;
+ goto done;
+ }
+ }
+