[PATCH] mv643xx_eth: Refactor/clean up tx queue handling

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 84 insertions, 177 deletions

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index 260be8048d3c..8a24b39f3ccb 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -62,6 +62,9 @@
 #define WRAP                    HW_IP_ALIGN + ETH_HLEN + VLAN_HLEN + FCS_LEN
 #define RX_SKB_SIZE             ((dev->mtu + WRAP + 7) & ~0x7)
 
+#define ETH_RX_QUEUES_ENABLED   (1 << 0)        /* use only Q0 for receive */
+#define ETH_TX_QUEUES_ENABLED   (1 << 0)        /* use only Q0 for transmit */
+
 #define INT_UNMASK_ALL                  0x0007ffff
 #define INT_UNMASK_ALL_EXT              0x0011ffff
 #define INT_MASK_ALL                    0x00000000
@@ -333,49 +336,78 @@ static void mv643xx_eth_tx_timeout_task(struct net_device *dev)
         netif_device_attach(dev);
 }
 
-/*
- * mv643xx_eth_free_tx_queue
- *
- * Input :      dev - a pointer to the required interface
+/**
+ * mv643xx_eth_free_tx_descs - Free the tx desc data for completed descriptors
  *
- * Output :     0 if was able to release skb , nonzero otherwise
+ * If force is non-zero, frees uncompleted descriptors as well
  */
-static int mv643xx_eth_free_tx_queue(struct net_device *dev,
-                                        unsigned int eth_int_cause_ext)
+int mv643xx_eth_free_tx_descs(struct net_device *dev, int force)
 {
         struct mv643xx_private *mp = netdev_priv(dev);
-        struct net_device_stats *stats = &mp->stats;
-        struct pkt_info pkt_info;
-        int released = 1;
+        struct eth_tx_desc *desc;
+        u32 cmd_sts;
+        struct sk_buff *skb;
+        unsigned long flags;
+        int tx_index;
+        dma_addr_t addr;
+        int count;
+        int released = 0;
 
-        if (!(eth_int_cause_ext & (BIT0 | BIT8)))
-                return released;
+        while (mp->tx_desc_count > 0) {
+                spin_lock_irqsave(&mp->lock, flags);
+                tx_index = mp->tx_used_desc_q;
+                desc = &mp->p_tx_desc_area[tx_index];
+                cmd_sts = desc->cmd_sts;
+
+                if (!force && (cmd_sts & ETH_BUFFER_OWNED_BY_DMA)) {
+                        spin_unlock_irqrestore(&mp->lock, flags);
+                        return released;
+                }
+
+                mp->tx_used_desc_q = (tx_index + 1) % mp->tx_ring_size;
+                mp->tx_desc_count--;
+
+                addr = desc->buf_ptr;
+                count = desc->byte_cnt;
+                skb = mp->tx_skb[tx_index];
+                if (skb)
+                        mp->tx_skb[tx_index] = NULL;
+
+                spin_unlock_irqrestore(&mp->lock, flags);
 
-        /* Check only queue 0 */
-        while (eth_tx_return_desc(mp, &pkt_info) == ETH_OK) {
-                if (pkt_info.cmd_sts & BIT0) {
+                if (cmd_sts & BIT0) {
                         printk("%s: Error in TX\n", dev->name);
-                        stats->tx_errors++;
+                        mp->stats.tx_errors++;
                 }
 
-                if (pkt_info.cmd_sts & ETH_TX_FIRST_DESC)
-                        dma_unmap_single(NULL, pkt_info.buf_ptr,
-                                        pkt_info.byte_cnt,
-                                        DMA_TO_DEVICE);
+                if (cmd_sts & ETH_TX_FIRST_DESC)
+                        dma_unmap_single(NULL, addr, count, DMA_TO_DEVICE);
                 else
-                        dma_unmap_page(NULL, pkt_info.buf_ptr,
-                                        pkt_info.byte_cnt,
-                                        DMA_TO_DEVICE);
+                        dma_unmap_page(NULL, addr, count, DMA_TO_DEVICE);
 
-                if (pkt_info.return_info) {
-                        dev_kfree_skb_irq(pkt_info.return_info);
-                        released = 0;
-                }
+                if (skb)
+                        dev_kfree_skb_irq(skb);
+
+                released = 1;
         }
 
         return released;
 }
 
+static void mv643xx_eth_free_completed_tx_descs(struct net_device *dev)
+{
+        struct mv643xx_private *mp = netdev_priv(dev);
+
+        if (mv643xx_eth_free_tx_descs(dev, 0) &&
+            mp->tx_ring_size - mp->tx_desc_count >= MAX_DESCS_PER_SKB)
+                netif_wake_queue(dev);
+}
+
+static void mv643xx_eth_free_all_tx_descs(struct net_device *dev)
+{
+        mv643xx_eth_free_tx_descs(dev, 1);
+}
+
 /*
  * mv643xx_eth_receive
  *
@@ -547,15 +579,13 @@ static irqreturn_t mv643xx_eth_int_handler(int irq, void *dev_id,
                  */
                 mv_write(MV643XX_ETH_INTERRUPT_CAUSE_REG(port_num),
                                                         ~eth_int_cause);
-                if (eth_int_cause_ext != 0x0)
+                if (eth_int_cause_ext != 0x0) {
                         mv_write(MV643XX_ETH_INTERRUPT_CAUSE_EXTEND_REG
                                         (port_num), ~eth_int_cause_ext);
-
-                /* UDP change : We may need this */
-                if ((eth_int_cause_ext & 0x0000ffff) &&
-                    (mv643xx_eth_free_tx_queue(dev, eth_int_cause_ext) == 0) &&
-                    (mp->tx_ring_size - mp->tx_desc_count > MAX_DESCS_PER_SKB))
-                        netif_wake_queue(dev);
+                        /* UDP change : We may need this */
+                        if (eth_int_cause_ext & (BIT0 | BIT8))
+                                mv643xx_eth_free_completed_tx_descs(dev);
+                }
 #ifdef MV643XX_NAPI
         } else {
                 if (netif_rx_schedule_prep(dev)) {
@@ -596,14 +626,13 @@ static irqreturn_t mv643xx_eth_int_handler(int irq, void *dev_id,
                 if (mii_link_ok(&mp->mii)) {
                         mii_ethtool_gset(&mp->mii, &cmd);
                         mv643xx_eth_update_pscr(dev, &cmd);
+                        mv643xx_eth_port_enable_tx(port_num,
+                                                   ETH_TX_QUEUES_ENABLED);
                         if (!netif_carrier_ok(dev)) {
                                 netif_carrier_on(dev);
-                                if (mp->tx_ring_size - mp->tx_desc_count >
-                                                        MAX_DESCS_PER_SKB) {
+                                if (mp->tx_ring_size - mp->tx_desc_count >=
+                                                        MAX_DESCS_PER_SKB)
                                         netif_wake_queue(dev);
-                                        /* Start TX queue */
-                                        mv643xx_eth_port_enable_tx(port_num, mp->port_tx_queue_command);
-                                }
                         }
                 } else if (netif_carrier_ok(dev)) {
                         netif_stop_queue(dev);
@@ -735,9 +764,6 @@ static void ether_init_rx_desc_ring(struct mv643xx_private *mp)
         mp->rx_used_desc_q = 0;
 
         mp->rx_desc_area_size = rx_desc_num * sizeof(struct eth_rx_desc);
-
-        /* Enable queue 0 for this port */
-        mp->port_rx_queue_command = 1;
 }
 
 /*
@@ -779,9 +805,6 @@ static void ether_init_tx_desc_ring(struct mv643xx_private *mp)
         mp->tx_used_desc_q = 0;
 
         mp->tx_desc_area_size = tx_desc_num * sizeof(struct eth_tx_desc);
-
-        /* Enable queue 0 for this port */
-        mp->port_tx_queue_command = 1;
 }
 
 static int mv643xx_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
@@ -963,25 +986,14 @@ out_free_irq:
 static void mv643xx_eth_free_tx_rings(struct net_device *dev)
 {
         struct mv643xx_private *mp = netdev_priv(dev);
-        unsigned int port_num = mp->port_num;
-        unsigned int curr;
-        struct sk_buff *skb;
 
         /* Stop Tx Queues */
-        mv643xx_eth_port_disable_tx(port_num);
+        mv643xx_eth_port_disable_tx(mp->port_num);
 
-        /* Free outstanding skb's on TX rings */
-        for (curr = 0; mp->tx_desc_count && curr < mp->tx_ring_size; curr++) {
-                skb = mp->tx_skb[curr];
-                if (skb) {
-                        mp->tx_desc_count -= skb_shinfo(skb)->nr_frags;
-                        dev_kfree_skb(skb);
-                        mp->tx_desc_count--;
-                }
-        }
-        if (mp->tx_desc_count)
-                printk("%s: Error on Tx descriptor free - could not free %d"
-                                " descriptors\n", dev->name, mp->tx_desc_count);
+        /* Free outstanding skb's on TX ring */
+        mv643xx_eth_free_all_tx_descs(dev);
+
+        BUG_ON(mp->tx_used_desc_q != mp->tx_curr_desc_q);
 
         /* Free TX ring */
         if (mp->tx_sram_size)
@@ -1062,30 +1074,6 @@ static int mv643xx_eth_stop(struct net_device *dev)
 }
 
 #ifdef MV643XX_NAPI
-static void mv643xx_tx(struct net_device *dev)
-{
-        struct mv643xx_private *mp = netdev_priv(dev);
-        struct pkt_info pkt_info;
-
-        while (eth_tx_return_desc(mp, &pkt_info) == ETH_OK) {
-                if (pkt_info.cmd_sts & ETH_TX_FIRST_DESC)
-                        dma_unmap_single(NULL, pkt_info.buf_ptr,
-                                        pkt_info.byte_cnt,
-                                        DMA_TO_DEVICE);
-                else
-                        dma_unmap_page(NULL, pkt_info.buf_ptr,
-                                        pkt_info.byte_cnt,
-                                        DMA_TO_DEVICE);
-
-                if (pkt_info.return_info)
-                        dev_kfree_skb_irq(pkt_info.return_info);
-        }
-
-        if (netif_queue_stopped(dev) &&
-            mp->tx_ring_size - mp->tx_desc_count > MAX_DESCS_PER_SKB)
-                netif_wake_queue(dev);
-}
-
 /*
  * mv643xx_poll
  *
@@ -1099,7 +1087,7 @@ static int mv643xx_poll(struct net_device *dev, int *budget)
 
 #ifdef MV643XX_TX_FAST_REFILL
         if (++mp->tx_clean_threshold > 5) {
-                mv643xx_tx(dev);
+                mv643xx_eth_free_completed_tx_descs(dev);
                 mp->tx_clean_threshold = 0;
         }
 #endif
@@ -1156,11 +1144,9 @@ static int eth_alloc_tx_desc_index(struct mv643xx_private *mp)
 {
         int tx_desc_curr;
 
-        tx_desc_curr = mp->tx_curr_desc_q;
-
         BUG_ON(mp->tx_desc_count >= mp->tx_ring_size);
-        mp->tx_desc_count++;
 
+        tx_desc_curr = mp->tx_curr_desc_q;
         mp->tx_curr_desc_q = (tx_desc_curr + 1) % mp->tx_ring_size;
 
         BUG_ON(mp->tx_curr_desc_q == mp->tx_used_desc_q);
@@ -1180,7 +1166,6 @@ static void eth_tx_fill_frag_descs(struct mv643xx_private *mp,
         int frag;
         int tx_index;
         struct eth_tx_desc *desc;
-        struct net_device_stats *stats = &mp->stats;
 
         for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
                 skb_frag_t *this_frag = &skb_shinfo(skb)->frags[frag];
@@ -1205,7 +1190,6 @@ static void eth_tx_fill_frag_descs(struct mv643xx_private *mp,
                                                 this_frag->page_offset,
                                                 this_frag->size,
                                                 DMA_TO_DEVICE);
-                stats->tx_bytes += this_frag->size;
         }
 }
 
@@ -1215,21 +1199,21 @@ static void eth_tx_fill_frag_descs(struct mv643xx_private *mp,
  * Ensure the data for an skb to be transmitted is mapped properly,
  * then fill in descriptors in the tx hw queue and start the hardware.
  */
-static int eth_tx_submit_descs_for_skb(struct mv643xx_private *mp,
-                                       struct sk_buff *skb)
+static void eth_tx_submit_descs_for_skb(struct mv643xx_private *mp,
+                                        struct sk_buff *skb)
 {
         int tx_index;
         struct eth_tx_desc *desc;
         u32 cmd_sts;
         int length;
-        int tx_bytes = 0;
+        int nr_frags = skb_shinfo(skb)->nr_frags;
 
         cmd_sts = ETH_TX_FIRST_DESC | ETH_GEN_CRC | ETH_BUFFER_OWNED_BY_DMA;
 
         tx_index = eth_alloc_tx_desc_index(mp);
         desc = &mp->p_tx_desc_area[tx_index];
 
-        if (skb_shinfo(skb)->nr_frags) {
+        if (nr_frags) {
                 eth_tx_fill_frag_descs(mp, skb);
 
                 length = skb_headlen(skb);
@@ -1244,7 +1228,6 @@ static int eth_tx_submit_descs_for_skb(struct mv643xx_private *mp,
 
         desc->byte_cnt = length;
         desc->buf_ptr = dma_map_single(NULL, skb->data, length, DMA_TO_DEVICE);
-        tx_bytes += length;
 
         if (skb->ip_summed == CHECKSUM_HW) {
                 BUG_ON(skb->protocol != ETH_P_IP);
@@ -1276,9 +1259,9 @@ static int eth_tx_submit_descs_for_skb(struct mv643xx_private *mp,
 
         /* ensure all descriptors are written before poking hardware */
         wmb();
-        mv643xx_eth_port_enable_tx(mp->port_num, mp->port_tx_queue_command);
+        mv643xx_eth_port_enable_tx(mp->port_num, ETH_TX_QUEUES_ENABLED);
 
-        return tx_bytes;
+        mp->tx_desc_count += nr_frags + 1;
 }
 
 /**
@@ -1306,7 +1289,8 @@ static int mv643xx_eth_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
         spin_lock_irqsave(&mp->lock, flags);
 
-        stats->tx_bytes = eth_tx_submit_descs_for_skb(mp, skb);
+        eth_tx_submit_descs_for_skb(mp, skb);
+        stats->tx_bytes = skb->len;
         stats->tx_packets++;
         dev->trans_start = jiffies;
 
@@ -1893,7 +1877,7 @@ static void eth_port_start(struct net_device *dev)
                           MV643XX_ETH_PORT_SDMA_CONFIG_DEFAULT_VALUE);
 
         /* Enable port Rx. */
-        mv643xx_eth_port_enable_rx(port_num, mp->port_rx_queue_command);
+        mv643xx_eth_port_enable_rx(port_num, ETH_RX_QUEUES_ENABLED);
 
         /* Disable port bandwidth limits by clearing MTU register */
         mv_write(MV643XX_ETH_MAXIMUM_TRANSMIT_UNIT(port_num), 0);
@@ -2602,79 +2586,6 @@ static void mv643xx_mdio_write(struct net_device *dev, int phy_id, int location,
 }
 
 /*
- * eth_tx_return_desc - Free all used Tx descriptors
- *
- * DESCRIPTION:
- *      This routine returns the transmitted packet information to the caller.
- *      It uses the 'first' index to support Tx desc return in case a transmit
- *      of a packet spanned over multiple buffer still in process.
- *      In case the Tx queue was in "resource error" condition, where there are
- *      no available Tx resources, the function resets the resource error flag.
- *
- * INPUT:
- *      struct mv643xx_private  *mp             Ethernet Port Control srtuct.
- *      struct pkt_info         *p_pkt_info     User packet buffer.
- *
- * OUTPUT:
- *      Tx ring 'first' and 'used' indexes are updated.
- *
- * RETURN:
- *      ETH_OK on success
- *      ETH_ERROR otherwise.
- *
- */
-static ETH_FUNC_RET_STATUS eth_tx_return_desc(struct mv643xx_private *mp,
-                                                struct pkt_info *p_pkt_info)
-{
-        int tx_desc_used;
-        struct eth_tx_desc *p_tx_desc_used;
-        unsigned int command_status;
-        unsigned long flags;
-        int err = ETH_OK;
-
-        spin_lock_irqsave(&mp->lock, flags);
-
-        BUG_ON(mp->tx_desc_count < 0);
-        if (mp->tx_desc_count == 0) {
-                /* no more tx descs in use */
-                err = ETH_ERROR;
-                goto out;
-        }
-
-        /* Get the Tx Desc ring indexes */
-        tx_desc_used = mp->tx_used_desc_q;
-
-        p_tx_desc_used = &mp->p_tx_desc_area[tx_desc_used];
-
-        BUG_ON(p_tx_desc_used == NULL);
-
-        command_status = p_tx_desc_used->cmd_sts;
-        if (command_status & (ETH_BUFFER_OWNED_BY_DMA)) {
-                /* Still transmitting... */
-                err = ETH_ERROR;
-                goto out;
-        }
-
-        /* Pass the packet information to the caller */
-        p_pkt_info->cmd_sts = command_status;
-        p_pkt_info->return_info = mp->tx_skb[tx_desc_used];
-        p_pkt_info->buf_ptr = p_tx_desc_used->buf_ptr;
-        p_pkt_info->byte_cnt = p_tx_desc_used->byte_cnt;
-        mp->tx_skb[tx_desc_used] = NULL;
-
-        /* Update the next descriptor to release. */
-        mp->tx_used_desc_q = (tx_desc_used + 1) % mp->tx_ring_size;
-
-        BUG_ON(mp->tx_desc_count == 0);
-        mp->tx_desc_count--;
-
-out:
-        spin_unlock_irqrestore(&mp->lock, flags);
-
-        return err;
-}
-
-/*
  * eth_port_receive - Get received information from Rx ring.
  *
  * DESCRIPTION:
diff --git a/drivers/net/mv643xx_eth.h b/drivers/net/mv643xx_eth.h
index 8768e1ba45df..cade2705423c 100644
--- a/drivers/net/mv643xx_eth.h
+++ b/drivers/net/mv643xx_eth.h
@@ -321,8 +321,6 @@ struct mv643xx_mib_counters {
 
 struct mv643xx_private {
         int port_num;                   /* User Ethernet port number    */
-        u32 port_tx_queue_command;      /* Port active Tx queues summary*/
-        u32 port_rx_queue_command;      /* Port active Rx queues summary*/
 
         u32 rx_sram_addr;               /* Base address of rx sram area */
         u32 rx_sram_size;               /* Size of rx sram area         */
@@ -411,8 +409,6 @@ static void eth_port_read_smi_reg(unsigned int eth_port_num,
 static void eth_clear_mib_counters(unsigned int eth_port_num);
 
 /* Port data flow control routines */
-static ETH_FUNC_RET_STATUS eth_tx_return_desc(struct mv643xx_private *mp,
-                                              struct pkt_info *p_pkt_info);
 static ETH_FUNC_RET_STATUS eth_port_receive(struct mv643xx_private *mp,
                                             struct pkt_info *p_pkt_info);
 static ETH_FUNC_RET_STATUS eth_rx_return_buff(struct mv643xx_private *mp,