rtwn: check for error during attach

[Stefan Sperling]

rtwn_attach() may fail due to "unsupported test chip".
Unlikely to occur in practice, but still...

Index: ic/rtwn.c
===================================================================
RCS file: /cvs/src/sys/dev/ic/rtwn.c,v
retrieving revision 1.1
diff -u -p -r1.1 rtwn.c
--- ic/rtwn.c   9 Mar 2016 18:18:28 -0000       1.1
+++ ic/rtwn.c   9 Mar 2016 19:03:48 -0000
@@ -152,7 +152,7 @@ void                rtwn_stop(struct ifnet *);
 #define        rtwn_bb_write   rtwn_write_4
 #define rtwn_bb_read   rtwn_read_4
 
-void
+int
 rtwn_attach(struct device *pdev, struct rtwn_softc *sc)
 {
        struct ieee80211com *ic = &sc->sc_ic;
@@ -169,7 +169,7 @@ rtwn_attach(struct device *pdev, struct 
        error = rtwn_read_chipid(sc);
        if (error != 0) {
                printf("%s: unsupported test chip\n", sc->sc_pdev->dv_xname);
-               return;
+               return (ENXIO);
        }
 
        /* Determine number of Tx/Rx chains. */
@@ -250,6 +250,8 @@ rtwn_attach(struct device *pdev, struct 
        sc->sc_newstate = ic->ic_newstate;
        ic->ic_newstate = rtwn_newstate;
        ieee80211_media_init(ifp, rtwn_media_change, ieee80211_media_status);
+
+       return (0);
 }
 
 int
Index: ic/rtwnvar.h
===================================================================
RCS file: /cvs/src/sys/dev/ic/rtwnvar.h,v
retrieving revision 1.1
diff -u -p -r1.1 rtwnvar.h
--- ic/rtwnvar.h        9 Mar 2016 18:18:28 -0000       1.1
+++ ic/rtwnvar.h        9 Mar 2016 19:02:27 -0000
@@ -76,7 +76,7 @@ struct rtwn_softc {
        uint32_t                        rf_chnlbw[R92C_MAX_CHAINS];
 };
 
-void           rtwn_attach(struct device *, struct rtwn_softc *);
+int            rtwn_attach(struct device *, struct rtwn_softc *);
 int            rtwn_detach(struct rtwn_softc *, int);
 int            rtwn_activate(struct rtwn_softc *, int);
 int8_t         rtwn_get_rssi(struct rtwn_softc *, int, void *);
Index: pci/if_rtwn.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/if_rtwn.c,v
retrieving revision 1.16
diff -u -p -r1.16 if_rtwn.c
--- pci/if_rtwn.c       9 Mar 2016 18:18:28 -0000       1.16
+++ pci/if_rtwn.c       9 Mar 2016 19:07:13 -0000
@@ -305,6 +305,7 @@ rtwn_pci_attach(struct device *parent, s
                if (error != 0) {
                        printf("%s: could not allocate Tx buffers\n",
                            sc->sc_dev.dv_xname);
+                       rtwn_free_rx_list(sc);
                        return;
                }
        }
@@ -324,7 +325,13 @@ rtwn_pci_attach(struct device *parent, s
        sc->sc_sc.sc_ops.disable_intr = rtwn_disable_intr;
        sc->sc_sc.sc_ops.stop = rtwn_pci_stop;
        sc->sc_sc.sc_ops.is_oactive = rtwn_is_oactive;
-       rtwn_attach(&sc->sc_dev, &sc->sc_sc);
+       error = rtwn_attach(&sc->sc_dev, &sc->sc_sc);
+       if (error != 0) {
+               rtwn_free_rx_list(sc);
+               for (i = 0; i < RTWN_NTXQUEUES; i++)
+                       rtwn_free_tx_list(sc, i);
+               return;
+       }
 
        /* ifp is now valid */
        ifp = &sc->sc_sc.sc_ic.ic_if;