spidernet: separate hardware state from driver state.

This patch separates the hardware descriptor state from the
driver descriptor state, per (old) suggestion from Ben Herrenschmidt.
This compiles and boots and seems to work.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: Jens Osterkamp <Jens.Osterkamp@de.ibm.com>
Cc: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/spider_net.c

@@ -299,9 +299,9 @@ spider_net_get_mac_address(struct net_device *netdev)
  * returns the status as in the dmac_cmd_status field of the descriptor
  */
 static inline int
-spider_net_get_descr_status(struct spider_net_descr *descr)
+spider_net_get_descr_status(struct spider_net_hw_descr *hwdescr)
 {
-	return descr->dmac_cmd_status & SPIDER_NET_DESCR_IND_PROC_MASK;
+	return hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_IND_PROC_MASK;
 }
 
 /**
@@ -319,12 +319,12 @@ spider_net_free_chain(struct spider_net_card *card,
 	descr = chain->ring;
 	do {
 		descr->bus_addr = 0;
-		descr->next_descr_addr = 0;
+		descr->hwdescr->next_descr_addr = 0;
 		descr = descr->next;
 	} while (descr != chain->ring);
 
 	dma_free_coherent(&card->pdev->dev, chain->num_desc,
-	    chain->ring, chain->dma_addr);
+	    chain->hwring, chain->dma_addr);
 }
 
 /**
@@ -343,31 +343,34 @@ spider_net_init_chain(struct spider_net_card *card,
 {
 	int i;
 	struct spider_net_descr *descr;
+	struct spider_net_hw_descr *hwdescr;
 	dma_addr_t buf;
 	size_t alloc_size;
 
-	alloc_size = chain->num_desc * sizeof (struct spider_net_descr);
+	alloc_size = chain->num_desc * sizeof(struct spider_net_hw_descr);
 
-	chain->ring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
+	chain->hwring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
 		&chain->dma_addr, GFP_KERNEL);
 
-	if (!chain->ring)
+	if (!chain->hwring)
 		return -ENOMEM;
 
-	descr = chain->ring;
-	memset(descr, 0, alloc_size);
+	memset(chain->ring, 0, chain->num_desc * sizeof(struct spider_net_descr));
 
 	/* Set up the hardware pointers in each descriptor */
+	descr = chain->ring;
+	hwdescr = chain->hwring;
 	buf = chain->dma_addr;
-	for (i=0; i < chain->num_desc; i++, descr++) {
-		descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+	for (i=0; i < chain->num_desc; i++, descr++, hwdescr++) {
+		hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+		hwdescr->next_descr_addr = 0;
 
+		descr->hwdescr = hwdescr;
 		descr->bus_addr = buf;
-		descr->next_descr_addr = 0;
 		descr->next = descr + 1;
 		descr->prev = descr - 1;
 
-		buf += sizeof(struct spider_net_descr);
+		buf += sizeof(struct spider_net_hw_descr);
 	}
 	/* do actual circular list */
 	(descr-1)->next = chain->ring;
@@ -394,7 +397,7 @@ spider_net_free_rx_chain_contents(struct spider_net_card *card)
 	do {
 		if (descr->skb) {
 			dev_kfree_skb(descr->skb);
-			pci_unmap_single(card->pdev, descr->buf_addr,
+			pci_unmap_single(card->pdev, descr->hwdescr->buf_addr,
 					 SPIDER_NET_MAX_FRAME,
 					 PCI_DMA_BIDIRECTIONAL);
 		}
@@ -416,6 +419,7 @@ static int
 spider_net_prepare_rx_descr(struct spider_net_card *card,
 			    struct spider_net_descr *descr)
 {
+	struct spider_net_hw_descr *hwdescr = descr->hwdescr;
 	dma_addr_t buf;
 	int offset;
 	int bufsize;
@@ -434,11 +438,11 @@ spider_net_prepare_rx_descr(struct spider_net_card *card,
 		card->spider_stats.alloc_rx_skb_error++;
 		return -ENOMEM;
 	}
-	descr->buf_size = bufsize;
-	descr->result_size = 0;
-	descr->valid_size = 0;
-	descr->data_status = 0;
-	descr->data_error = 0;
+	hwdescr->buf_size = bufsize;
+	hwdescr->result_size = 0;
+	hwdescr->valid_size = 0;
+	hwdescr->data_status = 0;
+	hwdescr->data_error = 0;
 
 	offset = ((unsigned long)descr->skb->data) &
 		(SPIDER_NET_RXBUF_ALIGN - 1);
@@ -447,21 +451,21 @@ spider_net_prepare_rx_descr(struct spider_net_card *card,
 	/* iommu-map the skb */
 	buf = pci_map_single(card->pdev, descr->skb->data,
 			SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
-	descr->buf_addr = buf;
 	if (pci_dma_mapping_error(buf)) {
 		dev_kfree_skb_any(descr->skb);
 		if (netif_msg_rx_err(card) && net_ratelimit())
 			pr_err("Could not iommu-map rx buffer\n");
 		card->spider_stats.rx_iommu_map_error++;
-		descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+		hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
 	} else {
-		descr->next_descr_addr = 0;
+		hwdescr->buf_addr = buf;
+		hwdescr->next_descr_addr = 0;
 		wmb();
-		descr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED |
+		hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED |
 					 SPIDER_NET_DMAC_NOINTR_COMPLETE;
 
 		wmb();
-		descr->prev->next_descr_addr = descr->bus_addr;
+		descr->prev->hwdescr->next_descr_addr = descr->bus_addr;
 	}
 
 	return 0;
@@ -517,7 +521,7 @@ spider_net_refill_rx_chain(struct spider_net_card *card)
 	if (!spin_trylock_irqsave(&chain->lock, flags))
 		return;
 
-	while (spider_net_get_descr_status(chain->head) ==
+	while (spider_net_get_descr_status(chain->head->hwdescr) ==
 			SPIDER_NET_DESCR_NOT_IN_USE) {
 		if (spider_net_prepare_rx_descr(card, chain->head))
 			break;
@@ -679,6 +683,7 @@ spider_net_prepare_tx_descr(struct spider_net_card *card,
 			    struct sk_buff *skb)
 {
 	struct spider_net_descr *descr;
+	struct spider_net_hw_descr *hwdescr;
 	dma_addr_t buf;
 	unsigned long flags;
 
@@ -693,30 +698,32 @@ spider_net_prepare_tx_descr(struct spider_net_card *card,
 
 	spin_lock_irqsave(&card->tx_chain.lock, flags);
 	descr = card->tx_chain.head;
+	hwdescr = descr->hwdescr;
 	card->tx_chain.head = descr->next;
 
-	descr->buf_addr = buf;
-	descr->buf_size = skb->len;
-	descr->next_descr_addr = 0;
 	descr->skb = skb;
-	descr->data_status = 0;
+	hwdescr->buf_addr = buf;
+	hwdescr->buf_size = skb->len;
+	hwdescr->next_descr_addr = 0;
+	hwdescr->data_status = 0;
 
-	descr->dmac_cmd_status =
+	hwdescr->dmac_cmd_status =
 			SPIDER_NET_DESCR_CARDOWNED | SPIDER_NET_DMAC_NOCS;
 	spin_unlock_irqrestore(&card->tx_chain.lock, flags);
 
 	if (skb->protocol == htons(ETH_P_IP))
 		switch (skb->nh.iph->protocol) {
 		case IPPROTO_TCP:
-			descr->dmac_cmd_status |= SPIDER_NET_DMAC_TCP;
+			hwdescr->dmac_cmd_status |= SPIDER_NET_DMAC_TCP;
 			break;
 		case IPPROTO_UDP:
-			descr->dmac_cmd_status |= SPIDER_NET_DMAC_UDP;
+			hwdescr->dmac_cmd_status |= SPIDER_NET_DMAC_UDP;
 			break;
 		}
 
 	/* Chain the bus address, so that the DMA engine finds this descr. */
-	descr->prev->next_descr_addr = descr->bus_addr;
+	wmb();
+	descr->prev->hwdescr->next_descr_addr = descr->bus_addr;
 
 	card->netdev->trans_start = jiffies; /* set netdev watchdog timer */
 	return 0;
@@ -725,16 +732,17 @@ spider_net_prepare_tx_descr(struct spider_net_card *card,
 static int
 spider_net_set_low_watermark(struct spider_net_card *card)
 {
+	struct spider_net_descr *descr = card->tx_chain.tail;
+	struct spider_net_hw_descr *hwdescr;
 	unsigned long flags;
 	int status;
 	int cnt=0;
 	int i;
-	struct spider_net_descr *descr = card->tx_chain.tail;
 
 	/* Measure the length of the queue. Measurement does not
 	 * need to be precise -- does not need a lock. */
 	while (descr != card->tx_chain.head) {
-		status = descr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
+		status = descr->hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
 		if (status == SPIDER_NET_DESCR_NOT_IN_USE)
 			break;
 		descr = descr->next;
@@ -753,10 +761,12 @@ spider_net_set_low_watermark(struct spider_net_card *card)
 
 	/* Set the new watermark, clear the old watermark */
 	spin_lock_irqsave(&card->tx_chain.lock, flags);
-	descr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
-	if (card->low_watermark && card->low_watermark != descr)
-		card->low_watermark->dmac_cmd_status =
-		     card->low_watermark->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
+	descr->hwdescr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
+	if (card->low_watermark && card->low_watermark != descr) {
+		hwdescr = card->low_watermark->hwdescr;
+		hwdescr->dmac_cmd_status =
+		     hwdescr->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
+	}
 	card->low_watermark = descr;
 	spin_unlock_irqrestore(&card->tx_chain.lock, flags);
 	return cnt;
@@ -779,6 +789,7 @@ spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
 {
 	struct spider_net_descr_chain *chain = &card->tx_chain;
 	struct spider_net_descr *descr;
+	struct spider_net_hw_descr *hwdescr;
 	struct sk_buff *skb;
 	u32 buf_addr;
 	unsigned long flags;
@@ -787,8 +798,9 @@ spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
 	while (chain->tail != chain->head) {
 		spin_lock_irqsave(&chain->lock, flags);
 		descr = chain->tail;
+		hwdescr = descr->hwdescr;
 
-		status = spider_net_get_descr_status(descr);
+		status = spider_net_get_descr_status(hwdescr);
 		switch (status) {
 		case SPIDER_NET_DESCR_COMPLETE:
 			card->netdev_stats.tx_packets++;
@@ -824,9 +836,9 @@ spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
 		}
 
 		chain->tail = descr->next;
-		descr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
+		hwdescr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
 		skb = descr->skb;
-		buf_addr = descr->buf_addr;
+		buf_addr = hwdescr->buf_addr;
 		spin_unlock_irqrestore(&chain->lock, flags);
 
 		/* unmap the skb */
@@ -862,7 +874,7 @@ spider_net_kick_tx_dma(struct spider_net_card *card)
 
 	descr = card->tx_chain.tail;
 	for (;;) {
-		if (spider_net_get_descr_status(descr) ==
+		if (spider_net_get_descr_status(descr->hwdescr) ==
 				SPIDER_NET_DESCR_CARDOWNED) {
 			spider_net_write_reg(card, SPIDER_NET_GDTDCHA,
 					descr->bus_addr);
@@ -958,17 +970,18 @@ static void
 spider_net_pass_skb_up(struct spider_net_descr *descr,
 		       struct spider_net_card *card)
 {
+	struct spider_net_hw_descr *hwdescr= descr->hwdescr;
 	struct sk_buff *skb;
 	struct net_device *netdev;
 	u32 data_status, data_error;
 
-	data_status = descr->data_status;
-	data_error = descr->data_error;
+	data_status = hwdescr->data_status;
+	data_error = hwdescr->data_error;
 	netdev = card->netdev;
 
 	skb = descr->skb;
 	skb->dev = netdev;
-	skb_put(skb, descr->valid_size);
+	skb_put(skb, hwdescr->valid_size);
 
 	/* the card seems to add 2 bytes of junk in front
 	 * of the ethernet frame */
@@ -1044,9 +1057,10 @@ spider_net_decode_one_descr(struct spider_net_card *card)
 {
 	struct spider_net_descr_chain *chain = &card->rx_chain;
 	struct spider_net_descr *descr = chain->tail;
+	struct spider_net_hw_descr *hwdescr = descr->hwdescr;
 	int status;
 
-	status = spider_net_get_descr_status(descr);
+	status = spider_net_get_descr_status(hwdescr);
 
 	/* Nothing in the descriptor, or ring must be empty */
 	if ((status == SPIDER_NET_DESCR_CARDOWNED) ||
@@ -1057,7 +1071,7 @@ spider_net_decode_one_descr(struct spider_net_card *card)
 	chain->tail = descr->next;
 
 	/* unmap descriptor */
-	pci_unmap_single(card->pdev, descr->buf_addr,
+	pci_unmap_single(card->pdev, hwdescr->buf_addr,
 			SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
 
 	if ( (status == SPIDER_NET_DESCR_RESPONSE_ERROR) ||
@@ -1080,27 +1094,26 @@ spider_net_decode_one_descr(struct spider_net_card *card)
 	}
 
 	/* The cases we'll throw away the packet immediately */
-	if (descr->data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
+	if (hwdescr->data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
 		if (netif_msg_rx_err(card))
 			pr_err("%s: error in received descriptor found, "
 			       "data_status=x%08x, data_error=x%08x\n",
 			       card->netdev->name,
-			       descr->data_status, descr->data_error);
+			       hwdescr->data_status, hwdescr->data_error);
 		goto bad_desc;
 	}
 
-	if (descr->dmac_cmd_status & 0xfefe) {
+	if (hwdescr->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);
+			       hwdescr->dmac_cmd_status);
+		pr_err("buf_addr=x%08x\n", hwdescr->buf_addr);
+		pr_err("buf_size=x%08x\n", hwdescr->buf_size);
+		pr_err("next_descr_addr=x%08x\n", hwdescr->next_descr_addr);
+		pr_err("result_size=x%08x\n", hwdescr->result_size);
+		pr_err("valid_size=x%08x\n", hwdescr->valid_size);
+		pr_err("data_status=x%08x\n", hwdescr->data_status);
+		pr_err("data_error=x%08x\n", hwdescr->data_error);
 		pr_err("which=%ld\n", descr - card->rx_chain.ring);
 
 		card->spider_stats.rx_desc_error++;
@@ -1109,12 +1122,12 @@ spider_net_decode_one_descr(struct spider_net_card *card)
 
 	/* 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;
+	hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
 	return 1;
 
 bad_desc:
 	dev_kfree_skb_irq(descr->skb);
-	descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+	hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
 	return 0;
 }
 
@@ -2200,9 +2213,6 @@ spider_net_setup_netdev(struct spider_net_card *card)
 
 	card->options.rx_csum = SPIDER_NET_RX_CSUM_DEFAULT;
 
-	card->tx_chain.num_desc = tx_descriptors;
-	card->rx_chain.num_desc = rx_descriptors;
-
 	spider_net_setup_netdev_ops(netdev);
 
 	netdev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX;
@@ -2250,8 +2260,11 @@ spider_net_alloc_card(void)
 {
 	struct net_device *netdev;
 	struct spider_net_card *card;
+	size_t alloc_size;
 
-	netdev = alloc_etherdev(sizeof(struct spider_net_card));
+	alloc_size = sizeof(struct spider_net_card) +
+	   (tx_descriptors + rx_descriptors) * sizeof(struct spider_net_descr);
+	netdev = alloc_etherdev(alloc_size);
 	if (!netdev)
 		return NULL;
 
@@ -2262,6 +2275,11 @@ spider_net_alloc_card(void)
 	init_waitqueue_head(&card->waitq);
 	atomic_set(&card->tx_timeout_task_counter, 0);
 
+	card->rx_chain.num_desc = rx_descriptors;
+	card->rx_chain.ring = card->darray;
+	card->tx_chain.num_desc = tx_descriptors;
+	card->tx_chain.ring = card->darray + rx_descriptors;
+
 	return card;
 }
 

drivers/net/spider_net.h

@@ -25,7 +25,7 @@
 #ifndef _SPIDER_NET_H
 #define _SPIDER_NET_H
 
-#define VERSION "1.6 B"
+#define VERSION "1.6 C"
 
 #include "sungem_phy.h"
 
@@ -364,8 +364,8 @@ enum spider_net_int2_status {
 #define SPIDER_NET_DESCR_NOT_IN_USE		0xF0000000
 #define SPIDER_NET_DESCR_TXDESFLG		0x00800000
 
-struct spider_net_descr {
-	/* as defined by the hardware */
+/* Descriptor, as defined by the hardware */
+struct spider_net_hw_descr {
 	u32 buf_addr;
 	u32 buf_size;
 	u32 next_descr_addr;
@@ -374,13 +374,15 @@ struct spider_net_descr {
 	u32 valid_size;	/* all zeroes for tx */
 	u32 data_status;
 	u32 data_error;	/* all zeroes for tx */
+} __attribute__((aligned(32)));
 
-	/* used in the driver */
+struct spider_net_descr {
+	struct spider_net_hw_descr *hwdescr;
 	struct sk_buff *skb;
 	u32 bus_addr;
 	struct spider_net_descr *next;
 	struct spider_net_descr *prev;
-} __attribute__((aligned(32)));
+};
 
 struct spider_net_descr_chain {
 	spinlock_t lock;
@@ -388,6 +390,7 @@ struct spider_net_descr_chain {
 	struct spider_net_descr *tail;
 	struct spider_net_descr *ring;
 	int num_desc;
+	struct spider_net_hw_descr *hwring;
 	dma_addr_t dma_addr;
 };
 
@@ -464,6 +467,9 @@ struct spider_net_card {
 	struct net_device_stats netdev_stats;
 	struct spider_net_extra_stats spider_stats;
 	struct spider_net_options options;
+
+	/* Must be last item in struct */
+	struct spider_net_descr darray[0];
 };
 
 #define pr_err(fmt,arg...) \