The 7000 generation of iwm hawrdware requires that the driver sets a
bit in the CSR_GP_CNTRL register before accessing most other registers
or sending commands to the firmware. The device will keep paying attention
while this bit is set. In the driver, the act of setting this bit is
referred to as "locking the NIC".
With this diff, we avoid locking the NIC redundantly and perform accounting
of locking and unlocking. I am not seeing any of the warning messages
introduced in this diff. So the locking seems to be done correctly.
Also make sure that we don't unlock the NIC in iwm_notif_intr while a
command is being processed. Linux and Drangonfly do this, too, but their
implementation is different (they use a flag rather than a counter).
Index: if_iwm.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/if_iwm.c,v
retrieving revision 1.178
diff -u -p -r1.178 if_iwm.c
--- if_iwm.c 4 May 2017 09:03:42 -0000 1.178
+++ if_iwm.c 5 May 2017 13:46:24 -0000
@@ -908,6 +908,11 @@ iwm_nic_lock(struct iwm_softc *sc)
{
int rv = 0;
+ if (sc->sc_nic_locks > 0) {
+ sc->sc_nic_locks++;
+ return 1; /* already locked */
+ }
+
IWM_SETBITS(sc, IWM_CSR_GP_CNTRL,
IWM_CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
@@ -919,6 +924,7 @@ iwm_nic_lock(struct iwm_softc *sc)
IWM_CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY
| IWM_CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP, 15000)) {
rv = 1;
+ sc->sc_nic_locks++;
} else {
printf("%s: acquiring device failed\n", DEVNAME(sc));
IWM_WRITE(sc, IWM_CSR_RESET, IWM_CSR_RESET_REG_FLAG_FORCE_NMI);
@@ -930,8 +936,12 @@ iwm_nic_lock(struct iwm_softc *sc)
void
iwm_nic_unlock(struct iwm_softc *sc)
{
- IWM_CLRBITS(sc, IWM_CSR_GP_CNTRL,
- IWM_CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
+ if (sc->sc_nic_locks > 0) {
+ if (--sc->sc_nic_locks == 0)
+ IWM_CLRBITS(sc, IWM_CSR_GP_CNTRL,
+ IWM_CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
+ } else
+ printf("%s: NIC already unlocked\n", DEVNAME(sc));
}
void
@@ -1211,6 +1221,11 @@ iwm_reset_tx_ring(struct iwm_softc *sc,
bus_dmamap_sync(sc->sc_dmat, ring->desc_dma.map, 0,
ring->desc_dma.size, BUS_DMASYNC_PREWRITE);
sc->qfullmsk &= ~(1 << ring->qid);
+ /* 7000 family NICs are locked while commands are in progress. */
+ if (ring->qid == IWM_CMD_QUEUE && ring->queued > 0) {
+ if (sc->sc_device_family == IWM_DEVICE_FAMILY_7000)
+ iwm_nic_unlock(sc);
+ }
ring->queued = 0;
ring->cur = 0;
}
@@ -1589,6 +1604,10 @@ iwm_stop_device(struct iwm_softc *sc)
/* Make sure (redundant) we've released our request to stay awake */
IWM_CLRBITS(sc, IWM_CSR_GP_CNTRL,
IWM_CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
+ if (sc->sc_nic_locks > 0)
+ printf("%s: %d active NIC locks forcefully cleared\n",
+ DEVNAME(sc), sc->sc_nic_locks);
+ sc->sc_nic_locks = 0;
/* Stop the device, and put it in low power state */
iwm_apm_stop(sc);
@@ -3724,21 +3743,23 @@ iwm_send_cmd(struct iwm_softc *sc, struc
(char *)(void *)desc - (char *)(void *)ring->desc_dma.vaddr,
sizeof (*desc), BUS_DMASYNC_PREWRITE);
- IWM_SETBITS(sc, IWM_CSR_GP_CNTRL,
- IWM_CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
- if (!iwm_poll_bit(sc, IWM_CSR_GP_CNTRL,
- IWM_CSR_GP_CNTRL_REG_VAL_MAC_ACCESS_EN,
- (IWM_CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY |
- IWM_CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP), 15000)) {
- printf("%s: acquiring device failed\n", DEVNAME(sc));
- err = EBUSY;
- goto out;
+ /*
+ * Wake up the NIC to make sure that the firmware will see the host
+ * command - we will let the NIC sleep once all the host commands
+ * returned. This needs to be done only on 7000 family NICs.
+ */
+ if (sc->sc_device_family == IWM_DEVICE_FAMILY_7000) {
+ if (ring->queued == 0 && !iwm_nic_lock(sc)) {
+ err = EBUSY;
+ goto out;
+ }
}
#if 0
iwm_update_sched(sc, ring->qid, ring->cur, 0, 0);
#endif
/* Kick command ring. */
+ ring->queued++;
ring->cur = (ring->cur + 1) % IWM_TX_RING_COUNT;
IWM_WRITE(sc, IWM_HBUS_TARG_WRPTR, ring->qid << 8 | ring->cur);
@@ -3859,6 +3880,18 @@ iwm_cmd_done(struct iwm_softc *sc, struc
data->m = NULL;
}
wakeup(&ring->desc[pkt->hdr.idx]);
+
+ if (ring->queued == 0) {
+ DPRINTF(("%s: unexpected firmware response to command 0x%x\n",
+ DEVNAME(sc), IWM_WIDE_ID(pkt->hdr.flags, pkt->hdr.code)));
+ } else if (--ring->queued == 0) {
+ /*
+ * 7000 family NICs are locked while commands are in progress.
+ * All commands are now done so we may unlock the NIC again.
+ */
+ if (sc->sc_device_family == IWM_DEVICE_FAMILY_7000)
+ iwm_nic_unlock(sc);
+ }
}
#if 0
@@ -6733,9 +6766,6 @@ iwm_notif_intr(struct iwm_softc *sc)
ADVANCE_RXQ(sc);
}
-
- IWM_CLRBITS(sc, IWM_CSR_GP_CNTRL,
- IWM_CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
/*
* Tell the firmware what we have processed.
