Re: [lwip-users] ppp and GPRS

[Janusz U.]

> I'm no expert on PPP, but if you're hoping the sequential API is faster
> than the raw API, you're going to be disappointed.  It's much slower in
> most cases.

exactly. Your PPP is as efficient as your link connection and sio_read 
function. I've modified my sio_read function several times - it is hard to 
do it finally ideal with queues of OS like eg. freeRTOS, interrupts and flow 
control. You should check by debug console how often you receive ppp packets 
(netif: pppInput) and send packets (netif: pppOutput).

example:
static char comm_read_blocked[COMM_MAX];

int comm_read(int port, char *buf, int n)
{
char line;
int len;

if (n < 1) return COMM_ERRBUFSIZE;
comm_read_blocked[port] = 1;
comm_blockRx(port);
len = 0;
while (1) {         // readout
 // getc with line
 if (xQueueReceive( xCharsRx[port], buf, comRX_BLOCK_TIME ) != pdTRUE) {
   //kprintf("comm_read COMM_ERRNOCHAR!\n");
   if (!comm_read_blocked[port]) {
    comm_unblockRx(port);
    return COMM_READABORT;
   }
   if (len != 0) break;
 } else {
  if (*buf == comLINECHAR) {
   if (xQueueReceive( xLinesRx[port], &line, comRX_BLOCK_TIME ) != pdTRUE)
    kprintf("comm_read COMM_ERRQUEUE!\n");
  }

  if (xFlowCTL[port] == FLOWCTRL_SW) {
   switch(port) {
    case USART0:
     if (uxQueueMessagesWaiting(xCharsRx[USART0]) <= USART0_RX_LOWATER)
      USART0_clrRTS();
     break;

    case USART1:
     if (uxQueueMessagesWaiting(xCharsRx[USART1]) <= USART1_RX_LOWATER)
      USART1_clrRTS();
     break;

    case DUSART:
     break;

    default:
     comm_unblockRx(port);
     return COMM_ERRPORT;
   } // switch
  }
  buf++;
  len++;
  if (len >= n) break;    // buffer is full
 }
}
comm_unblockRx(port);
   return len;
}

best regards
Janusz U.