Spidernet RX Debugging printout

Add some debugging and error printing.

The show_rx_chain() prints out the status of the rx chain,
which shows that the status of the descriptors gets
messed up after the second & subsequent RX ramfulls.

Print out contents of bad packets if error occurs.
Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: James K Lewis <jklewis@us.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/spider_net.c

@@ -961,6 +961,34 @@ spider_net_pass_skb_up(struct spider_net_descr *descr,
 	card->netdev_stats.rx_bytes += skb->len;
 }
 
+#ifdef DEBUG
+static void show_rx_chain(struct spider_net_card *card)
+{
+	struct spider_net_descr_chain *chain = &card->rx_chain;
+	struct spider_net_descr *start= chain->tail;
+	struct spider_net_descr *descr= start;
+	int status;
+
+	int cnt = 0;
+	int cstat = spider_net_get_descr_status(descr);
+	printk(KERN_INFO "RX chain tail at descr=%ld\n",
+	     (start - card->descr) - card->tx_chain.num_desc);
+	status = cstat;
+	do
+	{
+		status = spider_net_get_descr_status(descr);
+		if (cstat != status) {
+			printk(KERN_INFO "Have %d descrs with stat=x%08x\n", cnt, cstat);
+			cstat = status;
+			cnt = 0;
+		}
+		cnt ++;
+		descr = descr->next;
+	} while (descr != start);
+	printk(KERN_INFO "Last %d descrs with stat=x%08x\n", cnt, cstat);
+}
+#endif
+
 /**
  * spider_net_decode_one_descr - processes an rx descriptor
  * @card: card structure
@@ -1021,6 +1049,24 @@ spider_net_decode_one_descr(struct spider_net_card *card)
 		goto bad_desc;
 	}
 
+	if (descr->dmac_cmd_status & 0xfefe) {
+		pr_err("%s: bad status, cmd_status=x%08x\n",
+			       card->netdev->name,
+			       descr->dmac_cmd_status);
+		pr_err("buf_addr=x%08x\n", descr->buf_addr);
+		pr_err("buf_size=x%08x\n", descr->buf_size);
+		pr_err("next_descr_addr=x%08x\n", descr->next_descr_addr);
+		pr_err("result_size=x%08x\n", descr->result_size);
+		pr_err("valid_size=x%08x\n", descr->valid_size);
+		pr_err("data_status=x%08x\n", descr->data_status);
+		pr_err("data_error=x%08x\n", descr->data_error);
+		pr_err("bus_addr=x%08x\n", descr->bus_addr);
+		pr_err("which=%ld\n", descr - card->rx_chain.ring);
+
+		card->spider_stats.rx_desc_error++;
+		goto bad_desc;
+	}
+
 	/* Ok, we've got a packet in descr */
 	spider_net_pass_skb_up(descr, card);
 	descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;