📄 dloadarm.c
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being built dynamically.
PARAMETERS
pkt A pkt_buffer_type struct in which the packet will be built.
val The word to be added to the packet.
DEPENDENCIES
START_BUILDING_PACKET must have been called on pkt before calling
this macro.
RETURN VALUE
None.
SIDE EFFECTS
Each argument is evaluated twice within this macro.
This macro is not an expression, not is it a single statement. It
must be called with a trailing semicolon.
===========================================================================*/
#define ADD_WORD_TO_PACKET(pkt,val) \
/*lint -e778 val or (val >> 8) may evaluate to zero. */ \
add_byte_to_packet(&pkt, (const byte)((val >> 8) & 0xFF)); /* high byte */ \
add_byte_to_packet(&pkt, (const byte)(val & 0xFF)) /* low byte */ \
/*lint +e778 */
/*===========================================================================
MACRO ADD_CRC_TO_PACKET
DESCRIPTION
This macro adds a word (LEAST significant byte first) to a packet
being built dynamically. This should only be used for the CRC,
since other words are supposed to be sent most significant byte
first.
PARAMETERS
pkt A pkt_buffer_type struct in which the packet will be built.
val The word to be added to the packet.
DEPENDENCIES
START_BUILDING_PACKET must have been called on pkt before calling
this macro.
RETURN VALUE
None.
SIDE EFFECTS
Each argument is evaluated twice within this macro.
This macro is not an expression, not is it a single statement. It
must be called with a trailing semicolon.
===========================================================================*/
#define ADD_CRC_TO_PACKET(pkt,val) \
add_byte_to_packet(&pkt, (const byte)(val & 0xFF)); /* low byte */ \
add_byte_to_packet(&pkt, (const byte)((val >> 8) & 0xFF)) /* high byte */
/*===========================================================================
MACRO ADD_STUFF_TO_PACKET
DESCRIPTION
This macro adds an arbitrary buffer of bytes to a packet being built
dynamically.
PARAMETERS
pkt A pkt_buffer_type struct in which the packet will be built.
data A pointer to byte (or array of bytes) containing the data to be added
len The number of bytes to be added to the packet.
DEPENDENCIES
START_BUILDING_PACKET must have been called on pkt before calling
this macro.
RETURN VALUE
None.
SIDE EFFECTS
None.
===========================================================================*/
#define ADD_STUFF_TO_PACKET(pkt,data,len) \
/*lint -e717 Yes, this is a do...while(0). */\
do { \
int stuff_i; \
\
for (stuff_i=0; stuff_i < len; stuff_i++) \
{ \
add_byte_to_packet(&pkt, data[stuff_i]); \
} \
} while (0) \
/*lint +e717 */
/*===========================================================================
MACRO ADD_STRING_TO_PACKET
DESCRIPTION
This macro adds a text string (null terminated) to a packet being built
dynamically. If the string is not null terminated or is longer than 20
characters, only the first 20 characters are added to the packet.
PARAMETERS
pkt A pkt_buffer_type struct in which the packet will be built.
str The string to be added to the packet.
DEPENDENCIES
START_BUILDING_PACKET must have been called on pkt before calling
this macro.
RETURN VALUE
None.
SIDE EFFECTS
None.
===========================================================================*/
#define ADD_STRING_TO_PACKET(pkt,str) \
/*lint -e717 Yes, this is a do...while(0). */ \
do { \
byte count = 0; \
byte stopping_point; \
\
stopping_point = dload_str_len(str); \
while (count < stopping_point) \
add_byte_to_packet(&pkt, str[count++]); \
} while (0) \
/*lint -e717 */
/*===========================================================================
MACRO FINISH_BUILDING_PACKET
DESCRIPTION
This macro completes the process of building a packet dynamically.
It just calls a function to do the work.
PARAMETERS
pkt A pkt_buffer_type struct in which the packet has been built.
DEPENDENCIES
START_BUILDING_PACKET must have been called on pkt before calling
this macro.
RETURN VALUE
None.
SIDE EFFECTS
None.
===========================================================================*/
#define FINISH_BUILDING_PACKET(pkt) \
finish_building_packet(&pkt)
/*-------------------------------------------------------------------------*/
/* Mask for CRC-16 polynomial:
**
** x^16 + x^12 + x^5 + 1
**
** This is more commonly referred to as CCITT-16.
** Note: the x^16 tap is left off, it's implicit.
*/
#define CRC_16_L_POLYNOMIAL 0x8408
/* Seed value for CRC register. The all ones seed is part of CCITT-16, as
** well as allows detection of an entire data stream of zeroes.
*/
#define CRC_16_L_SEED 0xFFFF
/* Residual CRC value to compare against return value of a CRC_16_L_STEP().
** Use CRC_16_L_STEP() to calculate a 16 bit CRC, complement the result,
** and append it to the buffer. When CRC_16_L_STEP() is applied to the
** unchanged entire buffer, and complemented, it returns CRC_16_L_OK.
** That is, it returns CRC_16_L_OK_NEG.
*/
#define CRC_16_L_OK 0x0F47
#define CRC_16_L_OK_NEG 0xF0B8
/*===========================================================================
MACRO CRC_16_L_STEP
DESCRIPTION
This macro calculates one byte step of an LSB-first 16-bit CRC.
It can be used to produce a CRC and to check a CRC.
PARAMETERS
xx_crc Current value of the CRC calculation, 16-bits
xx_c New byte to figure into the CRC, 8-bits
DEPENDENCIES
None
RETURN VALUE
The new CRC value, 16-bits. If this macro is being used to check a
CRC, and is run over a range of bytes, the return value will be equal
to CRC_16_L_OK_NEG if the CRC checks correctly according to the DMSS
Async Download Protocol Spec.
SIDE EFFECTS
xx_crc is evaluated twice within this macro.
===========================================================================*/
//extern word crc_16_l_table[]; /* Extern for macro (global) */
extern const word crc_16_l_table[];
#define CRC_16_L_STEP(xx_crc,xx_c) \
(((xx_crc) >> 8) ^ crc_16_l_table[((xx_crc) ^ (xx_c)) & 0x00ff])
/*===========================================================================
MACRO CRC_16_L_STEP
DESCRIPTION
This macro calculates one byte step of an LSB-first 16-bit CRC.
It can be used to produce a CRC and to check a CRC.
PARAMETERS
xx_crc Current value of the CRC calculation, 16-bits
xx_c New byte to figure into the CRC, 8-bits
DEPENDENCIES
None
RETURN VALUE
The new CRC value, 16-bits. If this macro is being used to check a
CRC, and is run over a range of bytes, the return value will be equal
to CRC_16_L_OK_NEG if the CRC checks correctly according to the DMSS
Async Download Protocol Spec.
SIDE EFFECTS
xx_crc is evaluated twice within this macro.
===========================================================================*/
/*
const word crc_16_l_table[ 256 ] = {
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
*/
#define CRC_16_L_STEP(xx_crc,xx_c) \
(((xx_crc) >> 8) ^ crc_16_l_table[((xx_crc) ^ (xx_c)) & 0x00ff])
/*===========================================================================
FUNCTION add_byte_to_packet
DESCRIPTION
This function adds a single byte to a packet that is being built
dynamically. It takes care of byte stuffing and checks for buffer
overflow.
This function is a helper function for the packet building macros
and should not be called directly.
DEPENDENCIES
The START_BUILDING_PACKET() macro should have been called on the
packet buffer before calling this function.
RETURN VALUE
None.
SIDE EFFECTS
None.
===========================================================================*/
static void add_byte_to_packet
(
pkt_buffer_type *pkt,
/* Structure containing the packet being built */
const byte val
/* The byte to be added to the packet */
)
{
if (pkt->broken != FALSE) /* If the packet is broken already, */
{
return; /* Don't do anything. */
}
/* Check if the byte needs escaping for transparency. */
if (val == ASYNC_HDLC_FLAG || val == ASYNC_HDLC_ESC)
{
/* Check for an impending overflow. */
if (pkt->length+2+ROOM_FOR_CRC+ROOM_FOR_FLAG >= MAX_RESPONSE_LEN)
{
pkt->broken = TRUE; /* Overflow. Mark this packet broken. */
return;
}
/* No overflow. Escape the byte into the buffer. */
pkt->buf[pkt->length++] = ASYNC_HDLC_ESC;
pkt->buf[pkt->length++] = val ^ (byte)ASYNC_HDLC_ESC_MASK;
}
else /* Byte doesn't need escaping. */
{
/* Check for an impending overflow. */
if (pkt->length+1+ROOM_FOR_CRC+ROOM_FOR_FLAG >= MAX_RESPONSE_LEN)
{
pkt->broken = TRUE; /* Overflow. Mark this packet broken. */
return;
}
/* No overflow. Place the byte into the buffer. */
pkt->buf[pkt->length++] = val;
}
}/* add_byte_to_packet() */
/*===========================================================================
FUNCTION finish_building_packet
DESCRIPTION
This function completes the process of building a packet dynamically.
If all is well, it adds the CRC and a trailing flag to the buffer.
If an error has been encountered in building the packet, it substitutes
a NAK packet for whatever has been built.
This function is a helper function for the packet building macros
and should not be called directly.
DEPENDENCIES
The START_BUILDING_PACKET() macro should have been called on the
packet buffer before calling this function.
RETURN VALUE
None.
SIDE EFFECTS
None.
===========================================================================*/
static void finish_building_packet
(
pkt_buffer_type *pkt
/* Structure containing the packet being built */
)
{
word crc;
/* Cyclic Redundancy Check for the packet we've built. */
word i;
/* Index for scanning through the packet, computing the CRC. */
/*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/
if (pkt->broken == FALSE)
{
/* Compute the CRC for all the bytes in the packet. */
crc = CRC_16_L_SEED;
for (i=0; i < pkt->length; i++)
{
crc = CRC_16_L_STEP(crc, (word) pkt->buf[i]);
}
crc ^= CRC_16_L_SEED;
ADD_CRC_TO_PACKET(*pkt,crc); /* Add the CRC to the packet */
pkt->buf[pkt->length] = ASYNC_HDLC_FLAG; /* Add a flag to the packet.*/
/* This can't use the regular
add_byte_to_packet() function
because it's a flag. */
}
else
{
(void) memcpy((void*)pkt->buf, rsp_nak_invalid_len,
sizeof(rsp_nak_invalid_len)); /* Substitute a NAK */
}
}/* finish_building_packet() */
/*===========================================================================
FUNCTION transmit_packet
DESCRIPTION
This function transmits a packet response through the UART.
DEPENDENCIES
The packet must end with a flag.
RETURN VALUE
None.
SIDE EFFECTS
The watchdog may be reset.
===========================================================================*/
static void transmit_packet
(
pkt_buffer_type *pkt
/* The packet to be transmitted. */
)
{
const byte *data = (byte*) pkt->buf;
/* Pointer into the packet being transmitted */
/*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/
uart_transmit_byte(ASYNC_HDLC_FLAG); /* Supply the leading flag */
do
{
uart_transmit_byte(*data); /* Transmit bytes from the buffer */
}
while (*data++ != ASYNC_HDLC_FLAG); /* Until we've transmitted a flag */
} /* transmit_packet() */
/*===========================================================================
FUNCTION transmit_response
DESCRIPTION
This function transmits a packet response through the UART.
This function supplies the entire packet, based on the type
code passed in.
DEPENDENCIES
Uses the response_table[] to find the packet to transmit. This
packet must be terminated by a flag.
RETURN VALUE
None.
SIDE EFFECTS
The watchdog may be reset.
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