The lwIPTimer() function is called from the system tick interrupt timer. This
only increments the global variable g_ulLocalTimer.
It appears that the rest of the lwIP processing is all done in the Ethernet
interrupt. The interrupt function looks like the following:
lwIPEthernetIntHandler(void)
{
// Read and Clear the interrupt.
ulStatus = EthernetIntStatus(ETH_BASE, false);
EthernetIntClear(ETH_BASE, ulStatus);
// The handling of the interrupt is different based on the use of a RTOS.
// No RTOS is being used. If a transmit/receive interrupt was active,
// run the low-level interrupt handler.
if(ulStatus)
{
stellarisif_interrupt(&g_sNetIF);
}
// Service the lwIP timers.
lwIPServiceTimers();
}
It looks like all the work of the lwip processing, transmitting, and receiving
occurs in the function stellarisif_interrupt() which I included below:
stellarisif_interrupt(struct netif *netif)
{
struct stellarisif *stellarisif;
struct pbuf *p;
/* setup pointer to the if state data */
stellarisif = netif->state;
/**
* Process the transmit and receive queues as long as there is receive
* data available
*
*/
p = stellarisif_receive(netif);
while(p != NULL) {
/* process the packet */
if(ethernet_input(p, netif)!=ERR_OK) {
/* drop the packet */
LWIP_DEBUGF(NETIF_DEBUG, ("stellarisif_input: input error\n"));
pbuf_free(p);
/* Adjust the link statistics */
LINK_STATS_INC(link.memerr);
LINK_STATS_INC(link.drop);
}
/* Check if TX fifo is empty and packet available */
if((HWREG(ETH_BASE + MAC_O_TR) & MAC_TR_NEWTX) == 0) {
p = dequeue_packet(&stellarisif->txq);
if(p != NULL) {
stellarisif_transmit(netif, p);
}
}
/* Read another packet from the RX fifo */
p = stellarisif_receive(netif);
}
/* One more check of the transmit queue/fifo */
if((HWREG(ETH_BASE + MAC_O_TR) & MAC_TR_NEWTX) == 0) {
p = dequeue_packet(&stellarisif->txq);
if(p != NULL) {
stellarisif_transmit(netif, p);
}
}
}
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of
Simon Goldschmidt
Sent: Wednesday, March 16, 2011 12:16 PM
To: Mailing list for lwIP users
Subject: RE: [lwip-users] tcp_write() errors on snd_queuelen
If you try to protect tcp_write() against the ETH interrupt by disabling
interrupts, that would mean you would have to *always* disable the ETH
interrupt while calling into lwIP. That's pretty unperformant, I think.
As I already said before, the lwIP way is to prevent the driver calling into
lwIP from interrupt context.
_______________________________________________
lwip-users mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/lwip-users
_______________________________________________
lwip-users mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/lwip-users
