contiki/platform/jn516x/lib/slip.c

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2015-09-21 08:57:54 +00:00
/*
* Copyright (c) 2014, SICS Swedish ICT.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
*/
/**
* \file
* Alternative implementation for SLIP:
* 1. Accepts more than two packet
* 2. Disables UART rx interrupt when buffer is full
* (thus invoking flow control if configured)
* \author
* Niklas Finne <nfi@sics.se>
* Beshr Al Nahas <beshr@sics.se>
*
*/
#include "contiki.h"
#include <MicroInt.h>
#include "net/ip/uip.h"
#include "net/ipv4/uip-fw.h"
#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
#include "dev/slip.h"
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#define PUTCHAR(X) do { putchar(X); putchar('\n'); } while(0)
#else
#define PRINTF(...) do {} while(0)
#define PUTCHAR(X) do {} while(0)
#endif
#define SLIP_END 0300
#define SLIP_ESC 0333
#define SLIP_ESC_END 0334
#define SLIP_ESC_ESC 0335
#define SLIP_NEUTRAL 0 /* means: none of the above */
#define SLIP_ESC_XON 0336
#define SLIP_ESC_XOFF 0337
#define XON ((unsigned char)17)
#define XOFF ((unsigned char)19)
#if UART_XONXOFF_FLOW_CTRL
volatile unsigned char xonxoff_state = XON;
#endif /* UART_XONXOFF_FLOW_CTRL */
PROCESS(slip_process, "SLIP driver");
#include "dev/uart0.h"
#define STORE_UART_INTERRUPTS uart0_store_interrupts
#define RESTORE_UART_INTERRUPTS uart0_restore_interrupts
#define DISABLE_UART_INTERRUPTS uart0_disable_interrupts
#define ENABLE_UART_INTERRUPTS uart0_enable_interrupts
/**
* @brief A block of code may be made atomic by wrapping it with this
* macro. Something which is atomic cannot be interrupted by interrupts.
*/
/* A specific ATMOIC that disables UART interrupts only */
#define ATOMIC(blah) \
{ \
/* STORE_UART_INTERRUPTS(); */ \
DISABLE_UART_INTERRUPTS(); \
{ blah } \
/* RESTORE_UART_INTERRUPTS(); */ \
ENABLE_UART_INTERRUPTS(); \
}
/* A generic ATMOIC that disables all interrupts */
#define GLOBAL_ATOMIC(blah) \
{ \
MICRO_DISABLE_INTERRUPTS(); \
{ blah } \
MICRO_ENABLE_INTERRUPTS(); \
}
#if 1
#define SLIP_STATISTICS(statement)
#else
uint16_t slip_drop_bytes, slip_overflow, slip_error_drop;
/* No used in this file */
uint16_t slip_rubbish, slip_twopackets, slip_ip_drop;
unsigned long slip_received, slip_frames;
#define SLIP_STATISTICS(statement) statement
#endif
/* Must be at least one byte larger than UIP_BUFSIZE (for SLIP_END)! */
#ifdef SLIP_CONF_RX_BUFSIZE
#define RX_BUFSIZE SLIP_CONF_RX_BUFSIZE
#if RX_BUFSIZE < (UIP_BUFSIZE - UIP_LLH_LEN + 16)
#error "SLIP_CONF_RX_BUFSIZE too small for UIP_BUFSIZE"
#endif
#else
#define RX_BUFSIZE (UIP_CONF_BUFFER_SIZE * 2)
#endif
/*
* Variables begin and end manage the buffer space in a cyclic
* fashion. The first used byte is at begin and end is one byte past
* the last. I.e. [begin, end) is the actively used space.
*/
static volatile uint16_t begin, end, end_counter;
static uint8_t rxbuf[RX_BUFSIZE];
static volatile uint8_t is_dropping = 0;
static volatile uint8_t is_full = 0;
static void (*input_callback)(void) = NULL;
/*---------------------------------------------------------------------------*/
void
slip_set_input_callback(void (*c)(void))
{
input_callback = c;
}
static void
slip_write_char(uint8_t c)
{
/* Escape SLIP control characters */
if(c == SLIP_END) {
slip_arch_writeb(SLIP_ESC);
c = SLIP_ESC_END;
} else if(c == SLIP_ESC) {
slip_arch_writeb(SLIP_ESC);
c = SLIP_ESC_ESC;
}
#if UART_XONXOFF_FLOW_CTRL
/* Escape XON/XOFF characters */
else if(c == XON) {
slip_arch_writeb(SLIP_ESC);
c = SLIP_ESC_XON;
} else if(c == XOFF) {
slip_arch_writeb(SLIP_ESC);
c = SLIP_ESC_XOFF;
}
#endif /* UART_XONXOFF_FLOW_CTRL */
slip_arch_writeb(c);
}
/*---------------------------------------------------------------------------*/
uint8_t
slip_write(const void *_ptr, int len)
{
const uint8_t *ptr = _ptr;
uint16_t i;
uint8_t c;
slip_arch_writeb(SLIP_END);
for(i = 0; i < len; ++i) {
c = *ptr++;
slip_write_char(c);
}
slip_arch_writeb(SLIP_END);
return len;
}
/*---------------------------------------------------------------------------*/
/* slip_send: forward (IPv4) packets with {UIP_FW_NETIF(..., slip_send)}
* was used in slip-bridge.c
*/
uint8_t
slip_send(void)
{
uint16_t i;
uint8_t *ptr;
uint8_t c;
slip_arch_writeb(SLIP_END);
ptr = &uip_buf[UIP_LLH_LEN];
for(i = 0; i < uip_len; ++i) {
c = *ptr++;
slip_write_char(c);
}
slip_arch_writeb(SLIP_END);
return UIP_FW_OK;
}
/*---------------------------------------------------------------------------*/
static void
rxbuf_init(void)
{
begin = end = end_counter = 0;
is_dropping = 0;
}
/*---------------------------------------------------------------------------*/
/* Upper half does the polling. */
static uint16_t
slip_poll_handler(uint8_t *outbuf, uint16_t blen)
{
uint16_t len;
uint16_t pos;
uint8_t c;
uint8_t state;
if(end_counter == 0 && is_full == 0) {
return 0;
}
for(len = 0, pos = begin, state = c = SLIP_NEUTRAL;
len < blen + 1; /* +1 for SLIP_END! */
) {
c = rxbuf[pos++];
if(pos == RX_BUFSIZE) {
/* Circular buffer: warp around */
pos = 0;
}
if(c == SLIP_END) {
/* End of packet */
break;
}
if(len >= blen) {
/* End of buffer with no SLIP_END
* ==> something wrong happened */
break;
}
switch(c) {
case SLIP_ESC:
state = SLIP_ESC;
break;
case SLIP_ESC_END:
if(state == SLIP_ESC) {
outbuf[len++] = SLIP_END;
state = SLIP_NEUTRAL;
} else {
outbuf[len++] = c;
} break;
case SLIP_ESC_ESC:
if(state == SLIP_ESC) {
outbuf[len++] = SLIP_ESC;
state = SLIP_NEUTRAL;
} else {
outbuf[len++] = c;
} break;
#if UART_XONXOFF_FLOW_CTRL
case SLIP_ESC_XON:
if(state == SLIP_ESC) {
outbuf[len++] = XON;
state = SLIP_NEUTRAL;
} else {
outbuf[len++] = c;
} break;
case SLIP_ESC_XOFF:
if(state == SLIP_ESC) {
outbuf[len++] = XOFF;
state = SLIP_NEUTRAL;
} else {
outbuf[len++] = c;
} break;
#endif /* UART_XONXOFF_FLOW_CTRL */
default:
outbuf[len++] = c;
state = SLIP_NEUTRAL;
break;
}
}
/* Update counters */
if(c == SLIP_END) {
ATOMIC(begin = pos;
if(end_counter) {
end_counter--;
}
)
PUTCHAR('P');
} else {
/* Something went wrong, no SLIP_END found, drop everything */
ATOMIC(rxbuf_init();
is_dropping = 1;
)
SLIP_STATISTICS(slip_error_drop++);
len = 0;
PRINTF("SLIP: *** out of sync!\n");
}
if(end_counter > 0) {
/* One more packet is buffered, need to be polled again! */
process_poll(&slip_process);
}
return len;
}
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(slip_process, ev, data)
{
PROCESS_BEGIN();
rxbuf_init();
while(1) {
PROCESS_YIELD_UNTIL(ev == PROCESS_EVENT_POLL);
/* Move packet from rxbuf to buffer provided by uIP. */
uip_len = slip_poll_handler(&uip_buf[UIP_LLH_LEN],
UIP_BUFSIZE - UIP_LLH_LEN);
PRINTF("SLIP: recv bytes %u frames RECV: %u. is_full %u, is_dropping %u.\n",
end_counter, uip_len, is_full, is_dropping);
/* We have free space now, resume slip RX */
if(is_full) {
is_full = 0;
ENABLE_UART_INTERRUPTS();
}
if(uip_len > 0) {
if(input_callback) {
input_callback();
}
#ifdef SLIP_CONF_TCPIP_INPUT
SLIP_CONF_TCPIP_INPUT();
#else
tcpip_input();
#endif
}
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/
/* Return status from slip_input_byte:
* -1 means RX buffer overflow ==> stop reading
* 0 means do not exit power saving mode
* 1 means exit power saving mode
**/
int
slip_input_byte(unsigned char c)
{
static int in_frame = 0;
uint16_t next, next_next;
int error_return_code = is_full ? -1 : 0;
int success_return_code = is_full ? -1 : 1;
SLIP_STATISTICS(slip_received++);
#if UART_XONXOFF_FLOW_CTRL
if(c == XOFF || c == XON) {
xonxoff_state = c;
return 1;
} else {
/* ANY char would be XON */
xonxoff_state = XON;
}
#endif /* UART_XONXOFF_FLOW_CTRL */
if(is_dropping) {
/* Make sure to drop full frames when overflow or
* out of sync happens */
if(c != SLIP_END) {
SLIP_STATISTICS(slip_drop_bytes++);
} else {
is_dropping = 0;
in_frame = 0;
}
return error_return_code;
}
if(!in_frame && c == SLIP_END) {
/* Ignore slip end when not receiving frame */
return error_return_code;
/* increment and wrap */
}
next = end + 1;
if(next >= RX_BUFSIZE) {
next = 0;
}
next_next = next + 1;
if(next_next >= RX_BUFSIZE) {
next_next = 0;
/* Next byte will overflow. Stop accepting. */
}
if(next_next == begin) {
is_full = 1;
/* disable UART interrupts */
DISABLE_UART_INTERRUPTS();
process_poll(&slip_process);
}
/* Buffer is full. We can't store anymore.
* Shall not happen normally,
* because of overflow protection above. */
if(next == begin) {
is_dropping = 1;
SLIP_STATISTICS(slip_overflow++);
is_full = 1;
/* disable UART interrupts */
DISABLE_UART_INTERRUPTS();
process_poll(&slip_process);
return -1;
}
rxbuf[end] = c;
end = next;
in_frame = 1;
if(c == SLIP_END) {
in_frame = 0;
end_counter++;
SLIP_STATISTICS(slip_frames++);
process_poll(&slip_process);
return success_return_code;
}
return error_return_code;
}
/*---------------------------------------------------------------------------*/
#if SLIP_BRIDGE_CONF_NO_PUTCHAR
int
putchar(int c)
{
uart0_writeb(c);
return 1;
}
#endif