From 89d02670abc5cd4918045cb328ae74e1ff41188b Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Tue, 9 Jul 2013 12:55:01 +0000
Subject: [PATCH] Use MSI for xhci(4), if supported.

Reviewed by:	jhb
Tested by:	dchagin
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
---
 sys/dev/usb/controller/xhci.h     |  1 +
 sys/dev/usb/controller/xhci_pci.c | 24 ++++++++++++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/sys/dev/usb/controller/xhci.h b/sys/dev/usb/controller/xhci.h
index 0872f402cbc..3d436fdd0de 100644
--- a/sys/dev/usb/controller/xhci.h
+++ b/sys/dev/usb/controller/xhci.h
@@ -447,6 +447,7 @@ struct xhci_softc {
 
 	struct usb_device	*sc_devices[XHCI_MAX_DEVICES];
 	struct resource		*sc_io_res;
+	int			sc_irq_rid;
 	struct resource		*sc_irq_res;
 
 	void			*sc_intr_hdl;
diff --git a/sys/dev/usb/controller/xhci_pci.c b/sys/dev/usb/controller/xhci_pci.c
index 8695dac1370..0d897d994bc 100644
--- a/sys/dev/usb/controller/xhci_pci.c
+++ b/sys/dev/usb/controller/xhci_pci.c
@@ -146,8 +146,7 @@ static int
 xhci_pci_attach(device_t self)
 {
 	struct xhci_softc *sc = device_get_softc(self);
-	int err;
-	int rid;
+	int count, err, rid;
 
 	/* XXX check for 64-bit capability */
 
@@ -171,11 +170,21 @@ xhci_pci_attach(device_t self)
 
 	usb_callout_init_mtx(&sc->sc_callout, &sc->sc_bus.bus_mtx, 0);
 
-	rid = 0;
-	sc->sc_irq_res = bus_alloc_resource_any(self, SYS_RES_IRQ, &rid,
-	    RF_SHAREABLE | RF_ACTIVE);
+	sc->sc_irq_rid = 0;
+	count = pci_msi_count(self);
+	if (count >= 1) {
+		count = 1;
+		if (pci_alloc_msi(self, &count) == 0) {
+			if (bootverbose)
+				device_printf(self, "MSI enabled\n");
+			sc->sc_irq_rid = 1;
+		}
+	}
+	sc->sc_irq_res = bus_alloc_resource_any(self, SYS_RES_IRQ,
+	    &sc->sc_irq_rid, RF_SHAREABLE | RF_ACTIVE);
 	if (sc->sc_irq_res == NULL) {
 		device_printf(self, "Could not allocate IRQ\n");
+		goto error;
 	}
 	sc->sc_bus.bdev = device_add_child(self, "usbus", -1);
 	if (sc->sc_bus.bdev == NULL) {
@@ -249,7 +258,10 @@ xhci_pci_detach(device_t self)
 		sc->sc_intr_hdl = NULL;
 	}
 	if (sc->sc_irq_res) {
-		bus_release_resource(self, SYS_RES_IRQ, 0, sc->sc_irq_res);
+		if (sc->sc_irq_rid == 1)
+			pci_release_msi(self);
+		bus_release_resource(self, SYS_RES_IRQ, sc->sc_irq_rid,
+		    sc->sc_irq_res);
 		sc->sc_irq_res = NULL;
 	}
 	if (sc->sc_io_res) {