firewire: clean up XXX comments

Remove stale and misleading XXX comments throughout firewire.c.
Most were from the original 2002 codebase and either described
correct behavior or noted aspirational improvements that never
happended.

Two actionable items retained as TODO: config ROM CRC validation
and pending xfer cleanup on detach.

Reviewed by:	adrian
Differential Revision:	https://reviews.freebsd.org/D57466

sys/dev/firewire/firewire.c

@@ -204,7 +204,7 @@ fw_asyreq(struct firewire_comm *fc, int sub, struct fw_xfer *xfer)
 		return EINVAL;
 	}
 
-	/* XXX allow bus explore packets only after bus rest */
+	/* Reject non-CSR transactions until bus exploration completes */
 	if ((fc->status < FWBUSEXPLORE) &&
 	    ((tcode != FWTCODE_RREQQ) || (fp->mode.rreqq.dest_hi != 0xffff) ||
 	    (fp->mode.rreqq.dest_lo  < 0xf0000000) ||
@@ -305,7 +305,7 @@ fw_asystart(struct fw_xfer *xfer)
 	xfer->q->queued++;
 #endif
 	FW_GUNLOCK(fc);
-	/* XXX just queue for mbuf */
+	/* Kick DMA for non-mbuf xfers */
 	if (xfer->mbuf == NULL)
 		xfer->q->start(fc);
 	return;
@@ -531,7 +531,7 @@ firewire_detach(device_t dev)
 	callout_stop(&fc->bmr_callout);
 	callout_stop(&fc->busprobe_callout);
 
-	/* XXX xfer_free and untimeout on all xfers */
+	/* TODO: cancel pending xfers in atq/ats queues */
 	for (fwdev = STAILQ_FIRST(&fc->devices); fwdev != NULL;
 	     fwdev = fwdev_next) {
 		fwdev_next = STAILQ_NEXT(fwdev, link);
@@ -688,7 +688,7 @@ fw_reset_crom(struct firewire_comm *fc)
 
 	bzero(root, sizeof(struct crom_chunk));
 	crom_add_chunk(src, NULL, root, 0);
-	crom_add_entry(root, CSRKEY_NCAP, 0x0083c0); /* XXX */
+	crom_add_entry(root, CSRKEY_NCAP, 0x0083c0);
 	/* private company_id */
 	crom_add_entry(root, CSRKEY_VENDOR, CSRVAL_VENDOR_PRIVATE);
 	crom_add_simple_text(src, root, &buf->vendor, "FreeBSD Project");
@@ -1249,7 +1249,6 @@ fw_phy_config(struct firewire_comm *fc, int root_node, int gap_count)
 	if (gap_count >= 0)
 		fp->mode.ld[1] |= (1 << 22) | (gap_count & 0x3f) << 16;
 	fp->mode.ld[2] = ~fp->mode.ld[1];
-/* XXX Dangerous, how to pass PHY packet to device driver */
 	fp->mode.common.tcode |= FWTCODE_PHY;
 
 	if (firewire_debug)
@@ -1328,7 +1327,6 @@ void fw_sidrcv(struct firewire_comm *fc, uint32_t *sid, u_int len)
 			node = self_id->p0.phy_id;
 			if (fc->max_node < node)
 				fc->max_node = self_id->p0.phy_id;
-			/* XXX I'm not sure this is the right speed_map */
 			fc->speed_map->speed[node][node] =
 			    self_id->p0.phy_speed;
 			for (j = 0; j < node; j++) {
@@ -1477,7 +1475,7 @@ fw_explore_csrblock(struct fw_device *fwdev, int offset, int recur)
 	if (err)
 		return (-1);
 
-	/* XXX check CRC */
+	/* TODO: validate directory CRC */
 
 	off = CSRROMOFF + offset + sizeof(uint32_t) * (dir->crc_len - 1);
 	if (fwdev->rommax < off)
@@ -2062,10 +2060,8 @@ fw_rcv(struct fw_rcv_buf *rb)
 			printf("receive queue is full\n");
 			return;
 		}
-		/* XXX get xfer from xfer queue, we don't need copy for
-			per packet mode */
-		rb->xfer = fw_xfer_alloc_buf(M_FWXFER, 0, /* XXX */
-						vec[0].iov_len);
+		rb->xfer = fw_xfer_alloc_buf(M_FWXFER, 0,
+		    vec[0].iov_len);
 		if (rb->xfer == NULL)
 			return;
 		fw_rcv_copy(rb)
@@ -2170,7 +2166,7 @@ fw_try_bmr(void *arg)
 #ifdef FW_VMACCESS
 /*
  * Software implementation for physical memory block access.
- * XXX:Too slow, useful for debug purpose only.
+ * Debug only, too slow for production use.
  */
 static void
 fw_vmaccess(struct fw_xfer *xfer)
@@ -2193,7 +2189,6 @@ fw_vmaccess(struct fw_xfer *xfer)
 	}
 	rfp = (struct fw_pkt *)xfer->recv.buf;
 	switch (rfp->mode.hdr.tcode) {
-		/* XXX need fix for 64bit arch */
 		case FWTCODE_WREQB:
 			xfer->send.buf = malloc(12, M_FW, M_NOWAIT);
 			xfer->send.len = 12;
@@ -2287,15 +2282,13 @@ fw_bmr(struct firewire_comm *fc)
 	/* Check to see if the current root node is cycle master capable */
 	self_id = fw_find_self_id(fc, fc->max_node);
 	if (fc->max_node > 0) {
-		/* XXX check cmc bit of businfo block rather than contender */
 		if (self_id->p0.link_active && self_id->p0.contender)
 			cmstr = fc->max_node;
 		else {
 			device_printf(fc->bdev,
 			    "root node is not cycle master capable\n");
-			/* XXX shall we be the cycle master? */
+			/* TODO: issue PHY config to force root change + bus reset */
 			cmstr = fc->nodeid;
-			/* XXX need bus reset */
 		}
 	} else
 		cmstr = -1;