From 116bc58260c9ab29dcc220925fdb6a1c2abf3299 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Fri, 23 Oct 2020 18:18:45 +0000
Subject: [PATCH] xhci: Handle the case when MSI-X BAR is the same as IO BAR.

PCIe allows for MSI-X BAR to be either dedicated, or MSI-X Table may
be co-located in some functional BAR.  In the later case xhci(4) is
unable to allocate active resource for the table because BAR is
already activated.

Handle it by checking for this special case, and not try to alloc
resource if MSI-X BAR is IO.

Reported and tested by:	emaste
Reviewed by:	emaste, hselasky
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D26913
---
 sys/dev/usb/controller/xhci_pci.c | 34 +++++++++++++++++++------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/sys/dev/usb/controller/xhci_pci.c b/sys/dev/usb/controller/xhci_pci.c
index 15677c23b78..869f6a0aae2 100644
--- a/sys/dev/usb/controller/xhci_pci.c
+++ b/sys/dev/usb/controller/xhci_pci.c
@@ -277,21 +277,29 @@ xhci_pci_attach(device_t self)
 
 	rid = 0;
 	if (xhci_use_msix && (msix_table = pci_msix_table_bar(self)) >= 0) {
-		sc->sc_msix_res = bus_alloc_resource_any(self, SYS_RES_MEMORY,
-		    &msix_table, RF_ACTIVE);
-		if (sc->sc_msix_res == NULL) {
-			/* May not be enabled */
-			device_printf(self,
-			    "Unable to map MSI-X table \n");
+		if (msix_table == PCI_XHCI_CBMEM) {
+			sc->sc_msix_res = sc->sc_io_res;
 		} else {
+			sc->sc_msix_res = bus_alloc_resource_any(self,
+			    SYS_RES_MEMORY, &msix_table, RF_ACTIVE);
+			if (sc->sc_msix_res == NULL) {
+				/* May not be enabled */
+				device_printf(self,
+				    "Unable to map MSI-X table\n");
+			}
+		}
+		if (sc->sc_msix_res != NULL) {
 			count = 1;
 			if (pci_alloc_msix(self, &count) == 0) {
 				if (bootverbose)
 					device_printf(self, "MSI-X enabled\n");
 				rid = 1;
 			} else {
-				bus_release_resource(self, SYS_RES_MEMORY,
-				    msix_table, sc->sc_msix_res);
+				if (sc->sc_msix_res != sc->sc_io_res) {
+					bus_release_resource(self,
+					    SYS_RES_MEMORY,
+					    msix_table, sc->sc_msix_res);
+				}
 				sc->sc_msix_res = NULL;
 			}
 		}
@@ -387,16 +395,16 @@ xhci_pci_detach(device_t self)
 		sc->sc_irq_res = NULL;
 		pci_release_msi(self);
 	}
+	if (sc->sc_msix_res != NULL && sc->sc_msix_res != sc->sc_io_res) {
+		bus_release_resource(self, SYS_RES_MEMORY,
+		    rman_get_rid(sc->sc_msix_res), sc->sc_msix_res);
+		sc->sc_msix_res = NULL;
+	}
 	if (sc->sc_io_res) {
 		bus_release_resource(self, SYS_RES_MEMORY, PCI_XHCI_CBMEM,
 		    sc->sc_io_res);
 		sc->sc_io_res = NULL;
 	}
-	if (sc->sc_msix_res) {
-		bus_release_resource(self, SYS_RES_MEMORY,
-		    rman_get_rid(sc->sc_msix_res), sc->sc_msix_res);
-		sc->sc_msix_res = NULL;
-	}
 
 	xhci_uninit(sc);