bmp_can.c File Reference

CAN hardware interface code for BMP LPC1768. More...

#include "lpc17xx.h"
#include "lpc17xx_clkpwr.h"
#include "bmp.h"

Data Structures
struct	rx_desc_t
	Ethernet receive descriptor. More...
struct	tx_desc_t
	Ethernet transmit descriptor. More...
struct	stat_t
	Collects statistics about CAN messages. More...

Macros
#define	CAN_NUM_STR   8
	Number of CAN receive streams.
#define	TX_OPEN_RETRY   4
	Number of retries to open.
#define	TX_DATA_RETRY   4
	Number of retries to send data item.
#define	RX_CLOSE_RETRY   4
	Number of retries to close.
#define	CAN_OPEN_TO   1000
	Time for receiver to return CAN_OPEN_ACK.
#define	CAN_CLOSE_TO   1000
	Time for sender to return CAN_CLOSE_ACK.
#define	STAT(x)   stat.x++;
	Increment the named field in stat.
#define	MAX_PROC   1
	UPB of "proc_list" array.
#define	CAN_CLOCK   CLKPWR_PCLKSEL_CCLK_DIV_2
	Clock divisor for the CAN.

Enumerations
enum	can_sdp_command {   CAN_DATA = 0 , CAN_NACK = 1 , CAN_OPEN_REQ = 2 , CAN_OPEN_ACK = 3 ,   CAN_CLOSE_REQ = 4 , CAN_CLOSE_ACK = 5 , CAN_PROC = 6 , CAN_EXEC = 7 }
	CAN SDP command codes. More...
enum	can_sdp_sender_states { TX_IDLE = 0 , TX_OPEN_REQ = 1 , TX_DATA = 2 }
	CAN SDP sender states.
enum	can_sdp_receiver_states { RX_IDLE = 0 , RX_DATA = 1 , RX_CLOSE_REQ = 2 }
	CAN SDP receiver states.
enum	can_sdp_results { RC_SDP_NOREPLY = 0x8b , RC_SDP_REJECT = 0x8c , RC_SDP_BUSY = 0x8d , RC_SDP_TIMEOUT = 0x8e }
	SDP result codes that we care about (others are just passed through) More...
enum	can_exec_opcodes { CAN_EXEC_NOP = 0 , CAN_EXEC_REQ = 1 , CAN_EXEC_ACK = 2 }
	Sub-opcodes used by can_exec()

Functions
static void	can_tx1 (uint32_t dest, uint32_t id, uint32_t d1, uint32_t d2)
	Transmit using CAN buffer 1.
static void	can_tx2 (uint32_t dest, uint32_t id, uint32_t d1, uint32_t d2)
	Transmit using CAN buffer 2.
static void	can_tx3_nr (uint32_t dest, uint32_t id, uint32_t d1, uint32_t d2)
	Transmit using CAN buffer 3; no retries
static void	timeout_event (void *desc, event_proc proc, uint32_t arg2, uint32_t time)
	Schedule an event when a timeout occurs.
static void	can_open_ack (uint32_t id)
	Received an CAN_OPEN_ACK packet from receiver.
static void	can_close_req (uint32_t id)
	Received CAN_CLOSE_REQ from receiver.
static void	can_nack (uint32_t id)
	Received CAN_NACK from receiver because it found a packet out of sequence.
static void	can_data_timeout (uint32_t a1, uint32_t a2)
	Timed out waiting for CAN_CLOSE_REQ or CAN_NACK.
static void	can_open_timeout (uint32_t a1, uint32_t a2)
	Timed out waiting for CAN_OPEN_ACK.
uint32_t	can_send_msg (uint32_t dest, sdp_msg_t *msg)
	Send an SDP message over the CAN.
static void	can_open_req (uint32_t id)
	Someone wishes to send us an SDP packet; received CAN_OPEN_REQ.
static void	can_close_ack (uint32_t id)
	Received CAN_CLOSE_ACK from sender.
static void	can_close_timeout (uint32_t arg1, uint32_t arg2)
	Receiver timed out waiting for CAN_CLOSE_ACK.
static void	can_data (uint32_t id, uint32_t d1, uint32_t d2)
	Called when CAN_DATA packet arrives.
static void	can_proc (uint32_t id, uint32_t d1, uint32_t d2)
	Add a command immediately; handles CAN_PROC events.
void	proc_setup (uint32_t d1, uint32_t d2)
	Set up networking. Handles remote request across CAN from BMP master.
static void	can_exec (uint32_t id, uint32_t d1, uint32_t d2)
	Immediate execute. Arranges for proc_setup() to be called.
void	can_proc_cmd (uint32_t dest, uint32_t op, uint32_t arg1, uint32_t arg2)
	Asks another BMP to run a proc from proc_list.
void	can_timer (void)
	This is called every 10ms on all boards.
void	CAN_IRQHandler (void)
	Handler for receiving a message off the CAN.
void	configure_can (uint32_t id)
	Initialises the CAN controller.

Variables
uint32_t	config1
	Argument d1 to pass to proc_setup()
uint32_t	config2
	Argument d2 to pass to proc_setup()
uint8_t	can_status [CAN_SIZE]
	Whether a particular board is talking to the CAN bus.
static rx_desc_t	rx_desc_table [CAN_NUM_STR]
	Receive descriptors.
static tx_desc_t	tx_desc_str
	Transmit descriptor storage.
static tx_desc_t *	tx_desc = &tx_desc_str
	Transmit descriptor.
static uint32_t	bus_timeout
	Used to work out when to show the LED indicating a bus timeout.
static uint32_t	can_timeout
	Used to work out when to show the LED indicating a CAN timeout.
static bool	had_CAN_req
	Whether we had a request on the CAN bus.
stat_t	stat
	Collects statistics about CAN messages.
static const event_proc	proc_list []
	Operations that can be run "immediately" by can_proc()
uint32_t	can_req [CAN_SIZE]
	Count CAN_EXEC_REQ.
uint32_t	can_ack [CAN_SIZE]
	Count CAN_EXEC_ACK.
static uint32_t	can_next
	The index of the next board to talk to in can2board.
static uint32_t	can_seq
	Sequence number for CAN requests.

Detailed Description

CAN hardware interface code for BMP LPC1768.

Copyright

© The University of Manchester - 2012-2015

Author

Steve Temple, APT Group, School of Computer Science

---

Data Structure Documentation

rx_desc_t

struct rx_desc_t

Ethernet receive descriptor.

Data Fields
event_t *	event	Event and ID must be first in struct.
uint32_t	event_id
uint8_t	state	State variable.
uint8_t	tid	Tx ID of sender.
uint8_t	srce	Source address of sender.
uint8_t	last	Sequence number of last packet in message.
uint8_t	seq	Expected sequence number.
uint8_t	retry	Counts retries for can_close_req.
uint32_t *	buf	Pointer to buffer in SDP message.
sdp_msg_t *	msg	Pointer to SDP message.
uint32_t	Packet	Receive Packet Descriptor.
uint32_t	Ctrl	Receive Control Descriptor.

tx_desc_t

struct tx_desc_t

Ethernet transmit descriptor.

Data Fields
event_t *	event	Event and ID must be first in struct.
uint32_t	event_id
uint8_t	state	State variable.
uint8_t	rid	Rx ID at receiver.
uint8_t	tid	Tx ID.
volatile uint8_t	seq	Sequence number for sent DATA packets.
uint8_t	dest	Address of receiver.
uint8_t	rc	Return code.
uint8_t	delay	Packet delay (not used yet)
volatile uint8_t	ack	Ack variable set by interrupt routines.
uint32_t	Packet	Transmit Packet Descriptor.
uint32_t	Ctrl	Transmit Control Descriptor.

stat_t

struct stat_t

Collects statistics about CAN messages.

Data Fields
uint32_t	send_msg
uint32_t	rc_route
uint32_t	timeout
uint32_t	can_nack
uint32_t	close_req
uint32_t	data_timeout
uint32_t	open_timeout
uint32_t	open_ack
uint32_t	reject
uint32_t	close_ack
uint32_t	open_fail
uint32_t	rxseq_error

Enumeration Type Documentation

can_sdp_command

enum can_sdp_command

CAN SDP command codes.

Enumerator
CAN_DATA	Payload when sending SDP over CAN.
CAN_NACK	Restart sequence.
CAN_OPEN_REQ	Request to start sending.
CAN_OPEN_ACK	Permission to start sending.
CAN_CLOSE_REQ	Message complete.
CAN_CLOSE_ACK	Message complete acknowledge.
CAN_PROC	Initiate a "proc".
CAN_EXEC	Immediate command.

can_sdp_results

enum can_sdp_results

SDP result codes that we care about (others are just passed through)

Enumerator
RC_SDP_NOREPLY	No reply to open.
RC_SDP_REJECT	Open rejected.
RC_SDP_BUSY	Dest busy.
RC_SDP_TIMEOUT	Dest died?

Function Documentation

can_tx1()

static void can_tx1 ( uint32_t  dest, uint32_t  id, uint32_t  d1, uint32_t  d2  )

static

Transmit using CAN buffer 1.

Parameters

[in]	dest	who to transmit to
[in]	id	operation code?
[in]	d1	payload value 1
[in]	d2	payload value 2

can_tx2()

static void can_tx2 ( uint32_t  dest, uint32_t  id, uint32_t  d1, uint32_t  d2  )

static

Transmit using CAN buffer 2.

Parameters

[in]	dest	who to transmit to
[in]	id	operation code?
[in]	d1	payload value 1
[in]	d2	payload value 2

can_tx3_nr()

static void can_tx3_nr ( uint32_t  dest, uint32_t  id, uint32_t  d1, uint32_t  d2  )

static

Transmit using CAN buffer 3; no retries

Parameters

[in]	dest	who to transmit to
[in]	id	operation code?
[in]	d1	payload value 1
[in]	d2	payload value 2

timeout_event()

static void timeout_event ( void *  desc, event_proc  proc, uint32_t  arg2, uint32_t  time  )

static

Schedule an event when a timeout occurs.

Parameters

[in]	desc	A transmit descriptor or a receive descriptor. (Uses first two common fields only.)
[in]	proc	Callback to handle timeout
[in]	arg2	Second argument to callback
[in]	time	How far ahead to schedule the timeout

can_open_ack()

static void can_open_ack ( uint32_t  id )

static

Received an CAN_OPEN_ACK packet from receiver.

Unless return code says "busy" move to state TX_DATA and fill in "tx_desc". If busy, set a packet delay and allow more requests to be sent.

Parameters

[in]

id

Describes what is going on

can_close_req()

static void can_close_req ( uint32_t  id )

static

Received CAN_CLOSE_REQ from receiver.

If TX_DATA then signal in "ack". In any case, send a CAN_CLOSE_ACK back to receiver.

Parameters

[in]

id

Describes what is going on

can_nack()

static void can_nack ( uint32_t  id )

static

Received CAN_NACK from receiver because it found a packet out of sequence.

Restart from the sequence number provided by receiver.

Parameters

[in]

id

Describes what is going on

can_data_timeout()

static void can_data_timeout ( uint32_t  a1, uint32_t  a2  )

static

Timed out waiting for CAN_CLOSE_REQ or CAN_NACK.

Set "tx_desc->ack" to 3

Parameters

[in,out]	a1	Transmission descriptor
[in]	a2	Marker value (3)

can_open_timeout()

static void can_open_timeout ( uint32_t  a1, uint32_t  a2  )

static

Timed out waiting for CAN_OPEN_ACK.

Set "tx_desc->ack" to 2

Parameters

[in,out]	a1	Transmission descriptor
[in]	a2	Marker value (2)

can_send_msg()

uint32_t can_send_msg	(	uint32_t	dest,
		sdp_msg_t *	msg
	)

Send an SDP message over the CAN.

Parameters

[in]	dest	Which board to send to
[in]	msg	The message to send

Returns

SDP response code

can_open_req()

static void can_open_req ( uint32_t  id )

static

Someone wishes to send us an SDP packet; received CAN_OPEN_REQ.

Parameters

[in]

id

Describes what is going on

can_close_ack()

static void can_close_ack ( uint32_t  id )

static

Received CAN_CLOSE_ACK from sender.

Cancel timeout and go to IDLE

Parameters

[in]

id

Describes what is going on

can_close_timeout()

static void can_close_timeout ( uint32_t  arg1, uint32_t  arg2  )

static

Receiver timed out waiting for CAN_CLOSE_ACK.

Retry a few times and then give up, returning to IDLE

Parameters

[in]	arg1	Receive descriptor
[in]	arg2	Transaction ID

can_data()

static void can_data ( uint32_t  id, uint32_t  d1, uint32_t  d2  )

static

Called when CAN_DATA packet arrives.

Adds the payload to the SDP packet being reassembled if the message is meant for us and expected. If the packet has been fully received, add it into the main message system with msg_queue_insert()

Parameters

[in]	id	Describes what is going on
[in]	d1	First payload word
[in]	d2	Second payload word

can_proc()

static void can_proc ( uint32_t  id, uint32_t  d1, uint32_t  d2  )

static

Add a command immediately; handles CAN_PROC events.

Must be one of the ops listed in proc_list

Parameters

[in]	id	Describes what is going on
[in]	d1	First payload word
[in]	d2	Second payload word

proc_setup()

void proc_setup ( uint32_t  d1, uint32_t  d2  )

extern

Set up networking. Handles remote request across CAN from BMP master.

Parameters

[in]	d1	Combined hardware version, count of zero IP netmask bits, and frame ID
[in]	d2	IP gateway address. (Local addresses derive from this, frame ID and board ID.)

can_exec()

static void can_exec ( uint32_t  id, uint32_t  d1, uint32_t  d2  )

static

Immediate execute. Arranges for proc_setup() to be called.

Parameters

[in]	id	Describes what is going on
[in]	d1	First payload word
[in]	d2	Second payload word

can_proc_cmd()

void can_proc_cmd	(	uint32_t	dest,
		uint32_t	op,
		uint32_t	arg1,
		uint32_t	arg2
	)

Asks another BMP to run a proc from proc_list.

Parameters

[in]	dest	Who to ask
[in]	op	Describes what operation to run
[in]	arg1	First payload word
[in]	arg2	Second payload word

can_timer()

void can_timer

(

void

)

This is called every 10ms on all boards.

Non-zero boards just use it to timeout the CAN LED. The zero board uses it to ping all other boards and send them "config1" and "config2"

CAN_IRQHandler()

void CAN_IRQHandler

(

void

)

Handler for receiving a message off the CAN.

CAN request interrupt handler.

Delegates to:

• can_data()
• can_open_req()
• can_open_ack()
• can_nack()
• can_close_req()
• can_close_ack()
• can_proc()
• can_exec()

configure_can()

void configure_can

(

uint32_t

id

)

Initialises the CAN controller.

Parameters

[in]

id

Our ID

Variable Documentation

proc_list

const event_proc proc_list[]

static

Initial value:

= {
    proc_reset,
    proc_power,
    proc_led            
}

Operations that can be run "immediately" by can_proc()