pasemi_mac: rework ring management

pasemi_mac: rework ring management

Rework ring management, switching to an opaque ring format instead of
the struct-based descriptor+pointer setup, since it will be needed for
SG support.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 108 insertions, 128 deletions

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index b2861e0df86c..c2a3524a5411 100644
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -63,10 +63,10 @@
          NETIF_MSG_RX_ERR       | \
          NETIF_MSG_TX_ERR)
 
-#define TX_DESC(mac, num)       ((mac)->tx->desc[(num) & (TX_RING_SIZE-1)])
-#define TX_DESC_INFO(mac, num)  ((mac)->tx->desc_info[(num) & (TX_RING_SIZE-1)])
-#define RX_DESC(mac, num)       ((mac)->rx->desc[(num) & (RX_RING_SIZE-1)])
-#define RX_DESC_INFO(mac, num)  ((mac)->rx->desc_info[(num) & (RX_RING_SIZE-1)])
+#define TX_RING(mac, num)       ((mac)->tx->ring[(num) & (TX_RING_SIZE-1)])
+#define TX_RING_INFO(mac, num)  ((mac)->tx->ring_info[(num) & (TX_RING_SIZE-1)])
+#define RX_RING(mac, num)       ((mac)->rx->ring[(num) & (RX_RING_SIZE-1)])
+#define RX_RING_INFO(mac, num)  ((mac)->rx->ring_info[(num) & (RX_RING_SIZE-1)])
 #define RX_BUFF(mac, num)       ((mac)->rx->buffers[(num) & (RX_RING_SIZE-1)])
 
 #define RING_USED(ring)         (((ring)->next_to_fill - (ring)->next_to_clean) \
@@ -174,22 +174,21 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev)
         spin_lock_init(&ring->lock);
 
         ring->size = RX_RING_SIZE;
-        ring->desc_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
+        ring->ring_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
                                   RX_RING_SIZE, GFP_KERNEL);
 
-        if (!ring->desc_info)
-                goto out_desc_info;
+        if (!ring->ring_info)
+                goto out_ring_info;
 
         /* Allocate descriptors */
-        ring->desc = dma_alloc_coherent(&mac->dma_pdev->dev,
-                                        RX_RING_SIZE *
-                                        sizeof(struct pas_dma_xct_descr),
+        ring->ring = dma_alloc_coherent(&mac->dma_pdev->dev,
+                                        RX_RING_SIZE * sizeof(u64),
                                         &ring->dma, GFP_KERNEL);
 
-        if (!ring->desc)
-                goto out_desc;
+        if (!ring->ring)
+                goto out_ring_desc;
 
-        memset(ring->desc, 0, RX_RING_SIZE * sizeof(struct pas_dma_xct_descr));
+        memset(ring->ring, 0, RX_RING_SIZE * sizeof(u64));
 
         ring->buffers = dma_alloc_coherent(&mac->dma_pdev->dev,
                                            RX_RING_SIZE * sizeof(u64),
@@ -203,7 +202,7 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev)
 
         write_dma_reg(mac, PAS_DMA_RXCHAN_BASEU(chan_id),
                            PAS_DMA_RXCHAN_BASEU_BRBH(ring->dma >> 32) |
-                           PAS_DMA_RXCHAN_BASEU_SIZ(RX_RING_SIZE >> 2));
+                           PAS_DMA_RXCHAN_BASEU_SIZ(RX_RING_SIZE >> 3));
 
         write_dma_reg(mac, PAS_DMA_RXCHAN_CFG(chan_id),
                            PAS_DMA_RXCHAN_CFG_HBU(2));
@@ -229,11 +228,11 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev)
 
 out_buffers:
         dma_free_coherent(&mac->dma_pdev->dev,
-                          RX_RING_SIZE * sizeof(struct pas_dma_xct_descr),
-                          mac->rx->desc, mac->rx->dma);
-out_desc:
-        kfree(ring->desc_info);
-out_desc_info:
+                          RX_RING_SIZE * sizeof(u64),
+                          mac->rx->ring, mac->rx->dma);
+out_ring_desc:
+        kfree(ring->ring_info);
+out_ring_info:
         kfree(ring);
 out_ring:
         return -ENOMEM;
@@ -254,25 +253,24 @@ static int pasemi_mac_setup_tx_resources(struct net_device *dev)
         spin_lock_init(&ring->lock);
 
         ring->size = TX_RING_SIZE;
-        ring->desc_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
+        ring->ring_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
                                   TX_RING_SIZE, GFP_KERNEL);
-        if (!ring->desc_info)
-                goto out_desc_info;
+        if (!ring->ring_info)
+                goto out_ring_info;
 
         /* Allocate descriptors */
-        ring->desc = dma_alloc_coherent(&mac->dma_pdev->dev,
-                                        TX_RING_SIZE *
-                                        sizeof(struct pas_dma_xct_descr),
+        ring->ring = dma_alloc_coherent(&mac->dma_pdev->dev,
+                                        TX_RING_SIZE * sizeof(u64),
                                         &ring->dma, GFP_KERNEL);
-        if (!ring->desc)
-                goto out_desc;
+        if (!ring->ring)
+                goto out_ring_desc;
 
-        memset(ring->desc, 0, TX_RING_SIZE * sizeof(struct pas_dma_xct_descr));
+        memset(ring->ring, 0, TX_RING_SIZE * sizeof(u64));
 
         write_dma_reg(mac, PAS_DMA_TXCHAN_BASEL(chan_id),
                            PAS_DMA_TXCHAN_BASEL_BRBL(ring->dma));
         val = PAS_DMA_TXCHAN_BASEU_BRBH(ring->dma >> 32);
-        val |= PAS_DMA_TXCHAN_BASEU_SIZ(TX_RING_SIZE >> 2);
+        val |= PAS_DMA_TXCHAN_BASEU_SIZ(TX_RING_SIZE >> 3);
 
         write_dma_reg(mac, PAS_DMA_TXCHAN_BASEU(chan_id), val);
 
@@ -291,9 +289,9 @@ static int pasemi_mac_setup_tx_resources(struct net_device *dev)
 
         return 0;
 
-out_desc:
-        kfree(ring->desc_info);
-out_desc_info:
+out_ring_desc:
+        kfree(ring->ring_info);
+out_ring_info:
         kfree(ring);
 out_ring:
         return -ENOMEM;
@@ -304,31 +302,27 @@ static void pasemi_mac_free_tx_resources(struct net_device *dev)
         struct pasemi_mac *mac = netdev_priv(dev);
         unsigned int i;
         struct pasemi_mac_buffer *info;
-        struct pas_dma_xct_descr *dp;
-
-        for (i = 0; i < TX_RING_SIZE; i++) {
-                info = &TX_DESC_INFO(mac, i);
-                dp = &TX_DESC(mac, i);
-                if (info->dma) {
-                        if (info->skb) {
-                                pci_unmap_single(mac->dma_pdev,
-                                                 info->dma,
-                                                 info->skb->len,
-                                                 PCI_DMA_TODEVICE);
-                                dev_kfree_skb_any(info->skb);
-                        }
-                        info->dma = 0;
-                        info->skb = NULL;
-                        dp->mactx = 0;
-                        dp->ptr = 0;
+
+        for (i = 0; i < TX_RING_SIZE; i += 2) {
+                info = &TX_RING_INFO(mac, i+1);
+                if (info->dma && info->skb) {
+                        pci_unmap_single(mac->dma_pdev,
+                                         info->dma,
+                                         info->skb->len,
+                                         PCI_DMA_TODEVICE);
+                        dev_kfree_skb_any(info->skb);
                 }
+                TX_RING(mac, i) = 0;
+                TX_RING(mac, i+1) = 0;
+                info->dma = 0;
+                info->skb = NULL;
         }
 
         dma_free_coherent(&mac->dma_pdev->dev,
-                          TX_RING_SIZE * sizeof(struct pas_dma_xct_descr),
-                          mac->tx->desc, mac->tx->dma);
+                          TX_RING_SIZE * sizeof(u64),
+                          mac->tx->ring, mac->tx->dma);
 
-        kfree(mac->tx->desc_info);
+        kfree(mac->tx->ring_info);
         kfree(mac->tx);
         mac->tx = NULL;
 }
@@ -338,34 +332,31 @@ static void pasemi_mac_free_rx_resources(struct net_device *dev)
         struct pasemi_mac *mac = netdev_priv(dev);
         unsigned int i;
         struct pasemi_mac_buffer *info;
-        struct pas_dma_xct_descr *dp;
 
         for (i = 0; i < RX_RING_SIZE; i++) {
-                info = &RX_DESC_INFO(mac, i);
-                dp = &RX_DESC(mac, i);
-                if (info->skb) {
-                        if (info->dma) {
-                                pci_unmap_single(mac->dma_pdev,
-                                                 info->dma,
-                                                 info->skb->len,
-                                                 PCI_DMA_FROMDEVICE);
-                                dev_kfree_skb_any(info->skb);
-                        }
-                        info->dma = 0;
-                        info->skb = NULL;
-                        dp->macrx = 0;
-                        dp->ptr = 0;
+                info = &RX_RING_INFO(mac, i);
+                if (info->skb && info->dma) {
+                        pci_unmap_single(mac->dma_pdev,
+                                         info->dma,
+                                         info->skb->len,
+                                         PCI_DMA_FROMDEVICE);
+                        dev_kfree_skb_any(info->skb);
                 }
+                info->dma = 0;
+                info->skb = NULL;
         }
 
+        for (i = 0; i < RX_RING_SIZE; i++)
+                RX_RING(mac, i) = 0;
+
         dma_free_coherent(&mac->dma_pdev->dev,
-                          RX_RING_SIZE * sizeof(struct pas_dma_xct_descr),
-                          mac->rx->desc, mac->rx->dma);
+                          RX_RING_SIZE * sizeof(u64),
+                          mac->rx->ring, mac->rx->dma);
 
         dma_free_coherent(&mac->dma_pdev->dev, RX_RING_SIZE * sizeof(u64),
                           mac->rx->buffers, mac->rx->buf_dma);
 
-        kfree(mac->rx->desc_info);
+        kfree(mac->rx->ring_info);
         kfree(mac->rx);
         mac->rx = NULL;
 }
@@ -373,20 +364,22 @@ static void pasemi_mac_free_rx_resources(struct net_device *dev)
 static void pasemi_mac_replenish_rx_ring(struct net_device *dev, int limit)
 {
         struct pasemi_mac *mac = netdev_priv(dev);
-        unsigned int i;
         int start = mac->rx->next_to_fill;
-        int count;
+        unsigned int fill, count;
 
         if (limit <= 0)
                 return;
 
-        i = start;
+        fill = start;
         for (count = 0; count < limit; count++) {
-                struct pasemi_mac_buffer *info = &RX_DESC_INFO(mac, i);
-                u64 *buff = &RX_BUFF(mac, i);
+                struct pasemi_mac_buffer *info = &RX_RING_INFO(mac, fill);
+                u64 *buff = &RX_BUFF(mac, fill);
                 struct sk_buff *skb;
                 dma_addr_t dma;
 
+                /* Entry in use? */
+                WARN_ON(*buff);
+
                 /* skb might still be in there for recycle on short receives */
                 if (info->skb)
                         skb = info->skb;
@@ -407,7 +400,7 @@ static void pasemi_mac_replenish_rx_ring(struct net_device *dev, int limit)
                 info->skb = skb;
                 info->dma = dma;
                 *buff = XCT_RXB_LEN(BUF_SIZE) | XCT_RXB_ADDR(dma);
-                i++;
+                fill++;
         }
 
         wmb();
@@ -481,7 +474,6 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
 {
         unsigned int n;
         int count;
-        struct pas_dma_xct_descr *dp;
         struct pasemi_mac_buffer *info;
         struct sk_buff *skb;
         unsigned int i, len;
@@ -496,9 +488,7 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
 
                 rmb();
 
-                dp = &RX_DESC(mac, n);
-                prefetchw(dp);
-                macrx = dp->macrx;
+                macrx = RX_RING(mac, n);
 
                 if ((macrx & XCT_MACRX_E) ||
                     (*mac->rx_status & PAS_STATUS_ERROR))
@@ -516,12 +506,15 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
                  * interface ring.
                  */
 
-                dma = (dp->ptr & XCT_PTR_ADDR_M);
-                for (i = n; i < (n + RX_RING_SIZE); i++) {
-                        info = &RX_DESC_INFO(mac, i);
+                dma = (RX_RING(mac, n+1) & XCT_PTR_ADDR_M);
+                for (i = mac->rx->next_to_fill;
+                     i < (mac->rx->next_to_fill + RX_RING_SIZE);
+                     i++) {
+                        info = &RX_RING_INFO(mac, i);
                         if (info->dma == dma)
                                 break;
                 }
+
                 prefetchw(info);
 
                 skb = info->skb;
@@ -546,6 +539,11 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
                 } else
                         info->skb = NULL;
 
+                /* Need to zero it out since hardware doesn't, since the
+                 * replenish loop uses it to tell when it's done.
+                 */
+                RX_BUFF(mac, i) = 0;
+
                 skb_put(skb, len);
 
                 if (likely((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK)) {
@@ -561,13 +559,13 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
                 skb->protocol = eth_type_trans(skb, mac->netdev);
                 netif_receive_skb(skb);
 
-                dp->ptr = 0;
-                dp->macrx = 0;
+                RX_RING(mac, n) = 0;
+                RX_RING(mac, n+1) = 0;
 
-                n++;
+                n += 2;
         }
 
-        mac->rx->next_to_clean += limit - count;
+        mac->rx->next_to_clean = n;
         pasemi_mac_replenish_rx_ring(mac->netdev, limit-count);
 
         spin_unlock(&mac->rx->lock);
@@ -579,7 +577,6 @@ static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
 {
         int i;
         struct pasemi_mac_buffer *info;
-        struct pas_dma_xct_descr *dp;
         unsigned int start, count, limit;
         unsigned int total_count;
         unsigned long flags;
@@ -595,29 +592,28 @@ restart:
 
         count = 0;
 
-        for (i = start; i < limit; i++) {
-                dp = &TX_DESC(mac, i);
-
-                if ((dp->mactx & XCT_MACTX_E) ||
+        for (i = start; i < limit; i += 2) {
+                u64 mactx = TX_RING(mac, i);
+                if ((mactx  & XCT_MACTX_E) ||
                     (*mac->tx_status & PAS_STATUS_ERROR))
-                        pasemi_mac_tx_error(mac, dp->mactx);
+                        pasemi_mac_tx_error(mac, mactx);
 
-                if (unlikely(dp->mactx & XCT_MACTX_O))
+                if (unlikely(mactx & XCT_MACTX_O))
                         /* Not yet transmitted */
                         break;
 
-                info = &TX_DESC_INFO(mac, i);
+                info = &TX_RING_INFO(mac, i+1);
                 skbs[count] = info->skb;
                 dmas[count] = info->dma;
 
-                info->skb = NULL;
                 info->dma = 0;
-                dp->mactx = 0;
-                dp->ptr = 0;
+                TX_RING(mac, i) = 0;
+                TX_RING(mac, i+1) = 0;
+
 
                 count++;
         }
-        mac->tx->next_to_clean += count;
+        mac->tx->next_to_clean += count * 2;
         spin_unlock_irqrestore(&mac->tx->lock, flags);
         netif_wake_queue(mac->netdev);
 
@@ -1001,8 +997,6 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
 {
         struct pasemi_mac *mac = netdev_priv(dev);
         struct pasemi_mac_txring *txring;
-        struct pasemi_mac_buffer *info;
-        struct pas_dma_xct_descr *dp;
         u64 dflags, mactx, ptr;
         dma_addr_t map;
         unsigned long flags;
@@ -1038,13 +1032,13 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
 
         spin_lock_irqsave(&txring->lock, flags);
 
-        if (RING_AVAIL(txring) <= 1) {
+        if (RING_AVAIL(txring) <= 2) {
                 spin_unlock_irqrestore(&txring->lock, flags);
                 pasemi_mac_clean_tx(mac);
                 pasemi_mac_restart_tx_intr(mac);
                 spin_lock_irqsave(&txring->lock, flags);
 
-                if (RING_AVAIL(txring) <= 1) {
+                if (RING_AVAIL(txring) <= 2) {
                         /* Still no room -- stop the queue and wait for tx
                          * intr when there's room.
                          */
@@ -1053,15 +1047,14 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
                 }
         }
 
-        dp = &TX_DESC(mac, txring->next_to_fill);
-        info = &TX_DESC_INFO(mac, txring->next_to_fill);
+        TX_RING(mac, txring->next_to_fill) = mactx;
+        TX_RING(mac, txring->next_to_fill+1) = ptr;
+
+        TX_RING_INFO(mac, txring->next_to_fill+1).dma = map;
+        TX_RING_INFO(mac, txring->next_to_fill+1).skb = skb;
 
-        dp->mactx = mactx;
-        dp->ptr   = ptr;
-        info->dma = map;
-        info->skb = skb;
+        txring->next_to_fill += 2;
 
-        txring->next_to_fill++;
         dev->stats.tx_packets++;
         dev->stats.tx_bytes += skb->len;
 
diff --git a/drivers/net/pasemi_mac.h b/drivers/net/pasemi_mac.h
index c52cfcb6c4ca..5a896aa87a99 100644
--- a/drivers/net/pasemi_mac.h
+++ b/drivers/net/pasemi_mac.h
@@ -28,25 +28,25 @@
 
 struct pasemi_mac_txring {
         spinlock_t       lock;
-        struct pas_dma_xct_descr        *desc;
+        u64             *ring;
         dma_addr_t       dma;
         unsigned int     size;
         unsigned int     next_to_fill;
         unsigned int     next_to_clean;
-        struct pasemi_mac_buffer *desc_info;
+        struct pasemi_mac_buffer *ring_info;
         char             irq_name[10];  /* "eth%d tx" */
 };
 
 struct pasemi_mac_rxring {
         spinlock_t       lock;
-        struct pas_dma_xct_descr        *desc;  /* RX channel descriptor ring */
+        u64             *ring;  /* RX channel descriptor ring */
         dma_addr_t       dma;
         u64             *buffers;       /* RX interface buffer ring */
         dma_addr_t       buf_dma;
         unsigned int     size;
         unsigned int     next_to_fill;
         unsigned int     next_to_clean;
-        struct pasemi_mac_buffer *desc_info;
+        struct pasemi_mac_buffer *ring_info;
         char             irq_name[10];  /* "eth%d rx" */
 };
 
@@ -88,7 +88,7 @@ struct pasemi_mac {
         char    phy_id[BUS_ID_SIZE];
 };
 
-/* Software status descriptor (desc_info) */
+/* Software status descriptor (ring_info) */
 struct pasemi_mac_buffer {
         struct sk_buff *skb;
         dma_addr_t      dma;
@@ -101,20 +101,7 @@ struct pasdma_status {
         u64 tx_sta[20];
 };
 
-/* descriptor structure */
-struct pas_dma_xct_descr {
-        union {
-                u64     mactx;
-                u64     macrx;
-        };
-        union {
-                u64     ptr;
-                u64     rxb;
-        };
-};
-
 /* MAC CFG register offsets */
-
 enum {
         PAS_MAC_CFG_PCFG = 0x80,
         PAS_MAC_CFG_TXP = 0x98,