/*
* $Id: bios.c 563 2007-07-30 20:53:26Z andfri $
*/
#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>
#include <avr/pgmspace.h>
#include <string.h>
#include <util/crc16.h>
#include <config.h>
#include <vectors.h> // Must be included after sfr_defs.h but before any ISR()
#include <drivers/can/can.h>
#include <flash.h>
#include <bios_export.h>
#include CAN_DRIVER_H
#if defined(__AVR_ATmega8__)
#define IVSEL_REG GICR
#elif defined(__AVR_ATmega88__) || defined(__AVR_ATmega168__)
#define IVSEL_REG MCUCR
#else
#error AVR device not supported!
#endif
//---------------------------------------------------------------------------
// Private declarations
volatile uint8_t bios_msg_full;
Can_Message_t* bios_msg_ptr; // only a pointer to main-local structure to save .bss space
extern void __bios_start; // Start of BIOS area in flash, from ld-script.
#define BIOS_APP 1
#define BIOS_NOAPP 2
#define BIOS_PGM 3
//---------------------------------------------------------------------------
// Private functions
void Can_Process(Can_Message_t* msg) {
if (!(msg->ExtendedFlag)) return; // We don't care about standard CAN frames.
if ((msg->Id & CAN_MASK_CLASS)>>CAN_SHIFT_CLASS == CAN_NMT) {
if ((msg->Id & CAN_MASK_NMT_TYPE)>>CAN_SHIFT_NMT_TYPE == CAN_NMT_TIME) {
// Reset watchdog as long as time messages from the master node
// are received periodically. If anything hangs the CAN communication
// or the master node is not up, the node will be reset.
wdt_reset();
//TODO: Don't care about time right now... Figure out what to do with it.
}
if ((msg->Id & CAN_MASK_NMT_RID)>>CAN_SHIFT_NMT_RID == NODE_ID) {
if ((msg->Id & CAN_MASK_NMT_TYPE)>>CAN_SHIFT_NMT_TYPE == CAN_NMT_RESET) {
BIOS_Reset();
}
// Copy message to bios buffer if bios is done with the previous message.
// This is also a check to see if bios is still running. When app is
// started, bios_msg_full is never reset to 0 so the check fails and all
// NMT communication except reset is ignored.
if (!(bios_msg_full)) {
memcpy(bios_msg_ptr
, msg
, sizeof(Can_Message_t
)); bios_msg_full = 1;
}
}
} else if (BIOS_CanCallback) {
//printf("Calling app callback.\n");
BIOS_CanCallback(msg);
}
}
int main(void) {
void (*app_reset)(void) = 0; // Function pointer to jump to application reset vector.
uint8_t bios_state;
uint8_t nmt_type;
uint8_t pagebuf[SPM_PAGESIZE];
// These unneccessary initializations uses 12 bytes flash, just to make the compiler happy!
uint16_t base_addr = 0;
uint16_t offset = 0;
uint16_t addr = 0;
uint8_t len;
uint16_t data;
uint8_t send_msg = 0;
Can_Message_t tx_msg;
Can_Message_t bios_msg;
bios_msg_ptr = &bios_msg;
// Enable watchdog timer to protect against an application locking the
// node by leaving interrupts disabled.
wdt_enable(WDTO_2S);
// Move interrupt vectors to start of bootloader section and enable interrupts
IVSEL_REG = _BV(IVCE);
IVSEL_REG = _BV(IVSEL);
sei();
if (Can_Init() != CAN_OK) BIOS_Reset();
tx_msg.RemoteFlag = 0;
tx_msg.ExtendedFlag = 1;
tx_msg.Id = CAN_ID_NMT_BIOS_START;
tx_msg.DataLength = 3;
tx_msg.Data.words[0] = BIOS_VERSION;
if (pgm_read_word(0) == 0xffff) {
// No application in flash
// Send CAN_NMT_BIOS_START(BIOS_VERSION, 0)
tx_msg.Data.bytes[2] = 0;
bios_state = BIOS_NOAPP;
} else {
// Application exists
// Send CAN_NMT_BIOS_START(BIOS_VERSION, 1)
tx_msg.Data.bytes[2] = 1;
bios_state = BIOS_APP;
}
while (Can_Send(&tx_msg) != CAN_OK);
tx_msg.DataLength = 2; // All msg sent after BIOS_START are length 2 so set it once.
// Main loop
while (1) {
// Wait for message
while (!bios_msg_full);
nmt_type = (bios_msg.Id & CAN_MASK_NMT_TYPE)>>CAN_SHIFT_NMT_TYPE;
switch (bios_state) {
case BIOS_APP:
if (nmt_type == CAN_NMT_START_APP) {
app_reset(); // Will never return
}
// Fall through
case BIOS_NOAPP:
if (nmt_type == CAN_NMT_PGM_START) {
// Set base address
base_addr = bios_msg.Data.words[0];
flash_init(pagebuf);
//send CAN_NMT_PGM_ACK(offset)
tx_msg.Id = CAN_ID_NMT_PGM_ACK;
tx_msg.Data.words[0] = base_addr;
send_msg = 1;
bios_state = BIOS_PGM;
}
if (nmt_type == CAN_NMT_PGM_COPY) {
// For BIOS updating over CAN. Upload bios to application area,
// send this message with correct parameters to copy data from
// application to bios area and pray it will come alive again.
flash_copy_data(bios_msg.Data.words[0],
bios_msg.Data.words[1],
bios_msg.Data.words[2]);
// flash_copy_data will never return.
}
break;
case BIOS_PGM:
// Default to send CAN_NMT_PGM_ACK(offset)
tx_msg.Id = CAN_ID_NMT_PGM_ACK;
if (nmt_type == CAN_NMT_PGM_DATA) {
// Set address = base address + offset.
offset = bios_msg.Data.words[0];
addr = base_addr + offset;
// One of ACK and NACK will be sent, both have offset as data.
tx_msg.Data.words[0] = offset;
send_msg = 1;
// Flash all data sent, beginning at addr.
len = (bios_msg.DataLength+1)/2; // Number of words in message, rounded up.
uint8_t i;
for (i=1; i<len; i++) { // Skip first word (offset).
// Abort if trying to write in BIOS area.
if (addr >= (uint16_t)&__bios_start) {
// Send CAN_NMT_PGM_NACK(offset).
tx_msg.Id = CAN_ID_NMT_PGM_NACK;
break; //for loop
}
data = bios_msg.Data.words[i];
flash_write_word(addr, data);
addr += 2;
}
// Adjust addr if an odd number of bytes were sent, for use in crc calc.
addr -= bios_msg.DataLength & 1;
}
if (nmt_type == CAN_NMT_PGM_END) {
// Make sure a partly filled page will be flashed.
flash_flush_buffer();
// Calculate crc on written data.
//TODO: This will not work if data is not sent sequentially without
// holes, starting with offset=0. We might want to send a NACK if the
// offset in a CAN_NMT_PGM_DATA msg differs from the expected offset.
uint16_t loc, crc = 0;
for (loc = base_addr; loc < addr; loc++) { // addr will be last location written + 2.
crc = _crc16_update(crc, pgm_read_byte(loc));
}
tx_msg.Data.words[0] = crc;
send_msg = 1;
bios_state = BIOS_NOAPP;
}
}
if (send_msg) {
while (Can_Send(&tx_msg) != CAN_OK);
send_msg = 0;
}
bios_msg_full = 0; // We're done with this message, ready for the next.
}
return 0;
}