Re: [Qemu-devel] ARM ethernet fixes

[Paul Brook <paul@codesourcery.com>]

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On Thursday 15 December 2005 00:00, Paul Brook wrote:
> On Wednesday 14 December 2005 22:17, Daniel Jacobowitz wrote:
> > This is enough to let me use apt-get within qemu-system-arm :-)
>
> I'd totally missed that there were _two_ TX FIFOs.
>
> > @@ -364,6 +381,8 @@ static void smc91c111_writeb(void *opaqu
> >              return;
> >          case 12: /* Interrupt ACK.  */
> >              s->int_level &= ~(value & 0xd6);
> > +            if (value & INT_TX)
> > +                smc91c111_pop_tx_fifo_done(s);
> >              smc91c111_update(s);
> >              return;
>
> I'm fairly sure this is still wrong. We should only clear INT_TX if the tx
> completion fifo is empty. Maybe have smc91c111_update set the INT_TX bit if
> tx_fifo_done_len != 0.
>
> You also need to make smc91c111_reset, smc91c111_writeb: bank 2 offset 0
> cmd 2 (Reset MMU) and smc91c111_writeb: bank 2 offset 0 cmd 7 (Reset TX
> FIFO) set s->tx_fifo_done_len = 0.

Something like the attached patch.

Paul

[-- Attachment #2: patch --]
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=== hw/smc91c111.c
==================================================================
--- hw/smc91c111.c	(revision 1912)
+++ hw/smc91c111.c	(local)
@@ -35,8 +35,10 @@
     int tx_fifo[NUM_PACKETS];
     int rx_fifo_len;
     int rx_fifo[NUM_PACKETS];
+    int tx_fifo_done_len;
+    int tx_fifo_done[NUM_PACKETS];
     /* Packet buffer memory.  */
-    uint8_t data[2048][NUM_PACKETS];
+    uint8_t data[NUM_PACKETS][2048];
     uint8_t int_level;
     uint8_t int_mask;
     uint8_t macaddr[6];
@@ -81,6 +83,8 @@
 
     if (s->tx_fifo_len == 0)
         s->int_level |= INT_TX_EMPTY;
+    if (s->tx_fifo_done_len != 0)
+        s->int_level |= INT_TX;
     level = (s->int_level & s->int_mask) != 0;
     pic_set_irq_new(s->pic, s->irq, level);
 }
@@ -128,6 +132,18 @@
     smc91c111_update(s);
 }
 
+/* Remove an item from the TX completion FIFO.  */
+static void smc91c111_pop_tx_fifo_done(smc91c111_state *s)
+{
+    int i;
+
+    if (s->tx_fifo_done_len == 0)
+        return;
+    s->tx_fifo_done_len--;
+    for (i = 0; i < s->tx_fifo_done_len; i++)
+        s->tx_fifo_done[i] = s->tx_fifo_done[i + 1];
+}
+
 /* Release the memory allocated to a packet.  */
 static void smc91c111_release_packet(smc91c111_state *s, int packet)
 {
@@ -184,12 +200,13 @@
         add_crc = 0;
 #endif
         if (s->ctr & CTR_AUTO_RELEASE)
+            /* Race?  */
             smc91c111_release_packet(s, packetnum);
+        else if (s->tx_fifo_done_len < NUM_PACKETS)
+            s->tx_fifo_done[s->tx_fifo_done_len++] = packetnum;
         qemu_send_packet(s->vc, p, len);
     }
     s->tx_fifo_len = 0;
-    if ((s->ctr & CTR_AUTO_RELEASE) == 0)
-        s->int_level |= INT_TX;
     smc91c111_update(s);
 }
 
@@ -206,6 +223,7 @@
 {
     s->bank = 0;
     s->tx_fifo_len = 0;
+    s->tx_fifo_done_len = 0;
     s->rx_fifo_len = 0;
     s->allocated = 0;
     s->packet_num = 0;
@@ -306,6 +324,7 @@
             case 2: /* Reset MMU.  */
                 s->allocated = 0;
                 s->tx_fifo_len = 0;
+                s->tx_fifo_done_len = 0;
                 s->rx_fifo_len = 0;
                 s->tx_alloc = 0;
                 break;
@@ -326,6 +345,7 @@
                 break;
             case 7: /* Reset TX FIFO.  */
                 s->tx_fifo_len = 0;
+                s->tx_fifo_done_len = 0;
                 break;
             }
             return;
@@ -364,6 +384,8 @@
             return;
         case 12: /* Interrupt ACK.  */
             s->int_level &= ~(value & 0xd6);
+            if (value & INT_TX)
+                smc91c111_pop_tx_fifo_done(s);
             smc91c111_update(s);
             return;
         case 13: /* Interrupt mask.  */
@@ -473,10 +495,10 @@
         case 3: /* Allocation Result.  */
             return s->tx_alloc;
         case 4: /* TX FIFO */
-            if (s->tx_fifo_len == 0)
+            if (s->tx_fifo_done_len == 0)
                 return 0x80;
             else
-                return s->tx_fifo[0];
+                return s->tx_fifo_done[0];
         case 5: /* RX FIFO */
             if (s->rx_fifo_len == 0)
                 return 0x80;