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/*
* Copyright 2011-2013 Ettus Research LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <wb_uart.h>
#include <udp_uart.h>
#include <u3_net_stack.h>
/***********************************************************************
* Constants
**********************************************************************/
#define MAX_NUM_UARTS 4
static const size_t num_idle_cyc_b4_flush = 22;
/***********************************************************************
* Globals
**********************************************************************/
typedef struct
{
uint32_t uart_base;
struct ip_addr host_addr;
int host_ethno;
uint16_t host_port;
uint16_t local_port;
__attribute__ ((aligned (16))) uint8_t buf[256];
size_t len; //length of buffer
size_t cyc; //idle cycle count
} udp_uart_state_t;
static udp_uart_state_t _states[MAX_NUM_UARTS];
static int udp_uart_lookup(const uint16_t port)
{
for (size_t i = 0; i < MAX_NUM_UARTS; i++)
{
if (_states[i].local_port == port) return i;
}
return -1;
}
/***********************************************************************
* UDP handler for UARTs
**********************************************************************/
static void handle_uart_data_packet(
const uint8_t ethno,
const struct ip_addr *src, const struct ip_addr *dst,
const uint16_t src_port, const uint16_t dst_port,
const void *buff, const size_t num_bytes
){
//handle ICMP destination unreachable
if (buff == NULL)
{
const size_t which = udp_uart_lookup(src_port);
if (which == -1) return;
_states[which].host_port = 0;
}
//handle a regular blocking UART write
else
{
const size_t which = udp_uart_lookup(dst_port);
if (which == -1) return;
_states[which].host_ethno = ethno;
_states[which].host_addr = *src;
_states[which].host_port = src_port;
for (size_t i = 0; i < num_bytes; i++)
{
const char ch = ((const char *)buff)[i];
if (ch == '\n') wb_uart_putc(_states[which].uart_base, (int)'\r');
wb_uart_putc(_states[which].uart_base, (int)ch);
udp_uart_poll();
}
}
}
/***********************************************************************
* Public init function
**********************************************************************/
void udp_uart_init(const uint32_t uart_base, const uint16_t udp_port)
{
for (size_t i = 0; i < MAX_NUM_UARTS; i++)
{
if (_states[i].uart_base != 0) continue;
_states[i].uart_base = uart_base;
_states[i].local_port = udp_port;
_states[i].host_port = 0; //reset to null port
_states[i].len = 0;
_states[i].cyc = 0;
u3_net_stack_register_udp_handler(udp_port, &handle_uart_data_packet);
return;
}
}
/***********************************************************************
* Public poll function
**********************************************************************/
void udp_uart_poll(void)
{
for (size_t i = 0; i < MAX_NUM_UARTS; i++)
{
if (_states[i].uart_base == 0) continue;
bool newline = false;
udp_uart_state_t *state = &_states[i];
//read all characters we can without blocking
for (size_t j = state->len; j < sizeof(state->buf); j++)
{
int ret = wb_uart_getc(state->uart_base);
if (ret == -1) break;
char ch = (char) ret;
if (ch == '\n' || ch == '\r') newline = true;
state->buf[j] = ch;
state->len++;
state->cyc = 0; //reset idle cycles
}
//nothing in buffer, continue to next uart
if (state->len == 0) continue;
//send out a message if newline or forced flush
if (newline || state->cyc++ > num_idle_cyc_b4_flush)
{
if (state->host_port != 0) u3_net_stack_send_udp_pkt(
state->host_ethno,
&state->host_addr,
state->local_port,
state->host_port,
state->buf, state->len
);
state->len = 0;
state->cyc = 0;
}
}
}
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