I have updated the dmfe.c network driver for 2.4.0-test by adding proper
locking (I hope), and also made transmission much efficient.

I would appreciate any feedback from people using this driver, to confirm
that I did not break it.

It would also be great if someone could take a look at the lock handling,
to confirm that is is correct and sufficient.

/Tobias


--- dmfe.c.orig Wed Nov 15 19:53:48 2000
+++ dmfe.c      Wed Nov 15 21:35:24 2000
@@ -57,6 +57,11 @@
    Resource usage cleanups.
    Report driver version to user.
 
+   Tobias Ringström <[EMAIL PROTECTED]> :
+   Added proper locking.
+   Rewrote the transmit code to actually use the ring buffer,
+   and to generate a lot fewer interrupts.
+
    TODO
 
    Implement pci_driver::suspend() and pci_driver::resume()
@@ -108,6 +113,7 @@
 #define TX_MAX_SEND_CNT 0x1    /* Maximum tx packet per time */
 #define TX_DESC_CNT     0x10   /* Allocated Tx descriptors */
 #define RX_DESC_CNT     0x10   /* Allocated Rx descriptors */
+#define TX_IRQ_THR      12
 #define DESC_ALL_CNT    TX_DESC_CNT+RX_DESC_CNT
 #define TX_BUF_ALLOC    0x600
 #define RX_ALLOC_SIZE   0x620
@@ -188,6 +194,8 @@
        u32 cr7_data;
        u32 cr15_data;
        
+       spinlock_t lock;
+
        /* descriptor pointer */
        unsigned char *buf_pool_ptr;    /* Tx buffer pool memory */
        unsigned char *buf_pool_start;  /* Tx buffer pool align dword */
@@ -198,8 +206,7 @@
        struct rx_desc *first_rx_desc;
        struct rx_desc *rx_insert_ptr;
        struct rx_desc *rx_ready_ptr;   /* packet come pointer */
-       u32 tx_packet_cnt;      /* transmitted packet count */
-       u32 tx_queue_cnt;       /* wait to send packet count */
+       u32 tx_live_cnt;        /* number of used/live tx slots */
        u32 rx_avail_cnt;       /* available rx descriptor count */
        u32 interval_rx_cnt;    /* rx packet count a callback time */
 
@@ -490,8 +497,6 @@
 
        /* system variable init */
        db->cr6_data = CR6_DEFAULT | dmfe_cr6_user_set;
-       db->tx_packet_cnt = 0;
-       db->tx_queue_cnt = 0;
        db->rx_avail_cnt = 0;
        db->link_failed = 0;
        db->wait_reset = 0;
@@ -595,46 +600,42 @@
 {
        struct dmfe_board_info *db = dev->priv;
        struct tx_desc *txptr;
+       static unsigned pkt_num = TX_IRQ_THR;
 
        DMFE_DBUG(0, "dmfe_start_xmit", 0);
- 
-       netif_stop_queue(dev);
-       
-       /* Too large packet check */
-       if (skb->len > MAX_PACKET_SIZE) {
-               printk(KERN_ERR "%s: oversized frame (%d bytes) for transmit.\n", 
dev->name, (u16) skb->len);
-               dev_kfree_skb(skb);
-               return 0;
-       }
-       /* No Tx resource check, it never happen nromally */
-       if (db->tx_packet_cnt >= TX_FREE_DESC_CNT) {
-               return 1;
-       }
+
+       spin_lock_irq(&db->lock);
 
        /* transmit this packet */
        txptr = db->tx_insert_ptr;
        memcpy((char *) txptr->tx_buf_ptr, (char *) skb->data, skb->len);
-       txptr->tdes1 = 0xe1000000 | skb->len;
+       if (--pkt_num == 0)
+       {
+               txptr->tdes1 = 0xe1000000 | skb->len;
+               pkt_num = TX_IRQ_THR;
+       }
+       else
+               txptr->tdes1 = 0x61000000 | skb->len;
+
+       /* Transmit Packet Process */
+       txptr->tdes0 = 0x80000000;      /* set owner bit to DM910X */
+       outl(0x1, dev->base_addr + DCR1);       /* Issue Tx polling comand */
+       dev->trans_start = jiffies;     /* saved the time stamp */
 
        /* Point to next transmit free descriptor */
-       db->tx_insert_ptr = (struct tx_desc *) txptr->next_tx_desc;
+       txptr = (struct tx_desc *)txptr->next_tx_desc;
 
-       /* Transmit Packet Process */
-       if (db->tx_packet_cnt < TX_MAX_SEND_CNT) {
-               txptr->tdes0 = 0x80000000;      /* set owner bit to DM910X */
-               db->tx_packet_cnt++;    /* Ready to send count */
-               outl(0x1, dev->base_addr + DCR1);       /* Issue Tx polling comand */
-       } else {
-               db->tx_queue_cnt++;     /* queue the tx packet */
-               outl(0x1, dev->base_addr + DCR1);       /* Issue Tx polling comand */
-       }
+       if (txptr->tdes0 & 0x80000000)
+               netif_stop_queue(dev);
 
-       /* Tx resource check */
-       if (db->tx_packet_cnt < TX_FREE_DESC_CNT)
-               netif_wake_queue(dev);
+       db->tx_insert_ptr = txptr;
+       db->tx_live_cnt++;
+
+       spin_unlock_irq(&tp->lock);
 
        /* free this SKB */
        dev_kfree_skb(skb);
+
        return 0;
 }
 
@@ -713,12 +714,14 @@
                outl(0, ioaddr + DCR7);         /* disable all interrupt */
                return;
        }
+
+       spin_lock(&db->lock);
+
        /* Free the transmitted descriptor */
        txptr = db->tx_remove_ptr;
-       while (db->tx_packet_cnt) {
+       while (db->tx_live_cnt > 0 && (txptr->tdes0 & 0x80000000) == 0)
+       {
                /* printk("tdes0=%x\n", txptr->tdes0); */
-               if (txptr->tdes0 & 0x80000000)
-                       break;
                db->stats.tx_packets++;
                
                if ((txptr->tdes0 & TDES0_ERR_MASK) && (txptr->tdes0 != 0x7fffffff)) {
@@ -734,23 +737,16 @@
                                db->stats.tx_errors++;
                }
                txptr = (struct tx_desc *) txptr->next_tx_desc;
-               db->tx_packet_cnt--;
+               db->tx_live_cnt--;
        }
        /* Update TX remove pointer to next */
        db->tx_remove_ptr = (struct tx_desc *) txptr;
 
-       /* Send the Tx packet in queue */
-       if ((db->tx_packet_cnt < TX_MAX_SEND_CNT) && db->tx_queue_cnt) {
-               txptr->tdes0 = 0x80000000;      /* set owner bit to DM910X */
-               db->tx_packet_cnt++;    /* Ready to send count */
-               outl(0x1, ioaddr + DCR1);       /* Issue Tx polling command */
-               dev->trans_start = jiffies;     /* saved the time stamp */
-               db->tx_queue_cnt--;
-       }
-       /* Resource available check */
-       if (db->tx_packet_cnt < TX_FREE_DESC_CNT)
+       if ((db->tx_insert_ptr->tdes0 & 0x80000000) == 0)
                netif_wake_queue(dev);
 
+       spin_unlock(&db->lock);
+
        /* Received the coming packet */
        if (db->rx_avail_cnt)
                dmfe_rx_packet(dev, db);
@@ -930,12 +926,14 @@
 
        db->interval_rx_cnt = 0;
 
-       if (db->wait_reset | (db->tx_packet_cnt &&
-                             ((jiffies - dev->trans_start) > DMFE_TX_TIMEOUT)) | 
(db->rx_error_cnt > 3)) {
+       if (db->wait_reset ||
+           (db->tx_live_cnt > 0 &&
+            ((jiffies - dev->trans_start) > DMFE_TX_TIMEOUT)) ||
+           (db->rx_error_cnt > 3)) {
                /*
                   printk("wait_reset %x, tx cnt %x, rx err %x, time %x\n", 
db->wait_reset, db->tx_packet_cnt, db->rx_error_cnt, jiffies-dev->trans_start);
                 */
-               DMFE_DBUG(0, "Warn!! Warn!! Tx/Rx moniotr step1", db->tx_packet_cnt);
+               DMFE_DBUG(0, "Warn!! Warn!! Tx/Rx monitor step1", 0);
                dmfe_dynamic_reset(dev);
                db->timer.expires = DMFE_TIMER_WUT;
                add_timer(&db->timer);
@@ -1022,8 +1020,7 @@
        dmfe_free_rxbuffer(db);
 
        /* system variable init */
-       db->tx_packet_cnt = 0;
-       db->tx_queue_cnt = 0;
+       db->tx_live_cnt = 0;
        db->rx_avail_cnt = 0;
        db->link_failed = 0;
        db->wait_reset = 0;
@@ -1182,22 +1179,32 @@
 }
 
 /* Send a setup frame for DM9102/DM9102A
-   This setup frame initilize DM910X addres filter mode
+   This setup frame initilize DM910X address filter mode
  */
 static void send_filter_frame(struct net_device *dev, int mc_cnt)
 {
        struct dmfe_board_info *db = dev->priv;
        struct dev_mc_list *mcptr;
        struct tx_desc *txptr;
+       unsigned long flags;
        u16 *addrptr;
        u32 *suptr;
        int i;
 
        DMFE_DBUG(0, "send_filetr_frame()", 0);
 
+       spin_lock_irqsave(&db->lock, flags);
+
        txptr = db->tx_insert_ptr;
        suptr = (u32 *) txptr->tx_buf_ptr;
 
+       if (txptr->tdes0 & 0x80000000) {
+               spin_unlock_irq(&tp->lock);
+               printk(KERN_WARNING "%s: Too busy to send filter frame\n",
+                      dev->name);
+               return;
+       }
+
        /* Node address */
        addrptr = (u16 *) dev->dev_addr;
        *suptr++ = addrptr[0];
@@ -1224,19 +1231,15 @@
        }
        /* prepare the setup frame */
        db->tx_insert_ptr = (struct tx_desc *) txptr->next_tx_desc;
+       db->tx_live_cnt++;
        txptr->tdes1 = 0x890000c0;
-       /* Resource Check and Send the setup packet */
-       if (!db->tx_packet_cnt) {
-               /* Resource Empty */
-               db->tx_packet_cnt++;
-               txptr->tdes0 = 0x80000000;
-               update_cr6(db->cr6_data | 0x2000, dev->base_addr);
-               outl(0x1, dev->base_addr + DCR1);       /* Issue Tx polling command */
-               update_cr6(db->cr6_data, dev->base_addr);
-       } else {
-               /* Put into TX queue */
-               db->tx_queue_cnt++;
-       }
+       /* Send the setup packet */
+       txptr->tdes0 = 0x80000000;
+       update_cr6(db->cr6_data | 0x2000, dev->base_addr);
+       outl(0x1, dev->base_addr + DCR1);       /* Issue Tx polling command */
+       update_cr6(db->cr6_data, dev->base_addr);
+
+       spin_unlock_irqrestore(&tp->lock, flags);
 }
 
 /*

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