svn commit: r290195 - head/sys/dev/usb/controller

[Hans Petter Selasky]

Author: hselasky
Date: Fri Oct 30 14:50:29 2015
New Revision: 290195
URL: https://svnweb.freebsd.org/changeset/base/290195

Log:
  Reduce the DWC OTG interrupt load by not reading all the host channel
  status registers for every interrupt. Check a common host channel
  status interrupt register first, then conditionally read the
  individual host channel status registers.
  
  Submitted by:	Sebastian Huber <sebastian.huber at embedded-brains.de>
  MFC after:	1 week

Modified:
  head/sys/dev/usb/controller/dwc_otg.c

Modified: head/sys/dev/usb/controller/dwc_otg.c
==============================================================================
--- head/sys/dev/usb/controller/dwc_otg.c	Fri Oct 30 13:05:39 2015	(r290194)
+++ head/sys/dev/usb/controller/dwc_otg.c	Fri Oct 30 14:50:29 2015	(r290195)
@@ -2558,6 +2558,7 @@ dwc_otg_interrupt_poll_locked(struct dwc
 	struct usb_xfer *xfer;
 	uint32_t count;
 	uint32_t temp;
+	uint32_t haint;
 	uint8_t got_rx_status;
 	uint8_t x;
 
@@ -2575,14 +2576,18 @@ repeat:
 		DPRINTF("Yield\n");
 		return;
 	}
+
 	/* get all host channel interrupts */
-	for (x = 0; x != sc->sc_host_ch_max; x++) {
+	haint = DWC_OTG_READ_4(sc, DOTG_HAINT);
+	while (1) {
+		x = ffs(haint) - 1;
+		if (x >= sc->sc_host_ch_max)
+			break;
 		temp = DWC_OTG_READ_4(sc, DOTG_HCINT(x));
-		if (temp != 0) {
-			DWC_OTG_WRITE_4(sc, DOTG_HCINT(x), temp);
-			temp &= ~HCINT_SOFTWARE_ONLY;
-			sc->sc_chan_state[x].hcint |= temp;
-		}
+		DWC_OTG_WRITE_4(sc, DOTG_HCINT(x), temp);
+		temp &= ~HCINT_SOFTWARE_ONLY;
+		sc->sc_chan_state[x].hcint |= temp;
+		haint &= ~(1U << x);
 	}
 
 	if (sc->sc_last_rx_status == 0) {