ems_usb.c

/*
 * CAN driver for EMS Dr. Thomas Wuensche CPC-USB/ARM7
 *
 * Copyright (C) 2004-2009 EMS Dr. Thomas Wuensche
 *
 * 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; version 2 of the License.
 *
 * 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/usb.h>

#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>

MODULE_AUTHOR("Sebastian Haas <haas@ems-wuensche.com>");
MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
MODULE_LICENSE("GPL v2");

/* Control-Values for CPC_Control() Command Subject Selection */
#define CONTR_CAN_MESSAGE 0x04
#define CONTR_CAN_STATE   0x0C
#define CONTR_BUS_ERROR   0x1C

/* Control Command Actions */
#define CONTR_CONT_OFF 0
#define CONTR_CONT_ON  1
#define CONTR_ONCE     2

/* Messages from CPC to PC */
#define CPC_MSG_TYPE_CAN_FRAME       1  /* CAN data frame */
#define CPC_MSG_TYPE_RTR_FRAME       8  /* CAN remote frame */
#define CPC_MSG_TYPE_CAN_PARAMS      12 /* Actual CAN parameters */
#define CPC_MSG_TYPE_CAN_STATE       14 /* CAN state message */
#define CPC_MSG_TYPE_EXT_CAN_FRAME   16 /* Extended CAN data frame */
#define CPC_MSG_TYPE_EXT_RTR_FRAME   17 /* Extended remote frame */
#define CPC_MSG_TYPE_CONTROL         19 /* change interface behavior */
#define CPC_MSG_TYPE_CONFIRM         20 /* command processed confirmation */
#define CPC_MSG_TYPE_OVERRUN         21 /* overrun events */
#define CPC_MSG_TYPE_CAN_FRAME_ERROR 23 /* detected bus errors */
#define CPC_MSG_TYPE_ERR_COUNTER     25 /* RX/TX error counter */

/* Messages from the PC to the CPC interface  */
#define CPC_CMD_TYPE_CAN_FRAME     1   /* CAN data frame */
#define CPC_CMD_TYPE_CONTROL       3   /* control of interface behavior */
#define CPC_CMD_TYPE_CAN_PARAMS    6   /* set CAN parameters */
#define CPC_CMD_TYPE_RTR_FRAME     13  /* CAN remote frame */
#define CPC_CMD_TYPE_CAN_STATE     14  /* CAN state message */
#define CPC_CMD_TYPE_EXT_CAN_FRAME 15  /* Extended CAN data frame */
#define CPC_CMD_TYPE_EXT_RTR_FRAME 16  /* Extended CAN remote frame */
#define CPC_CMD_TYPE_CAN_EXIT      200 /* exit the CAN */

#define CPC_CMD_TYPE_INQ_ERR_COUNTER 25 /* request the CAN error counters */
#define CPC_CMD_TYPE_CLEAR_MSG_QUEUE 8  /* clear CPC_MSG queue */
#define CPC_CMD_TYPE_CLEAR_CMD_QUEUE 28 /* clear CPC_CMD queue */

#define CPC_CC_TYPE_SJA1000 2 /* Philips basic CAN controller */

#define CPC_CAN_ECODE_ERRFRAME 0x01 /* Ecode type */

/* Overrun types */
#define CPC_OVR_EVENT_CAN       0x01
#define CPC_OVR_EVENT_CANSTATE  0x02
#define CPC_OVR_EVENT_BUSERROR  0x04

/*
 * If the CAN controller lost a message we indicate it with the highest bit
 * set in the count field.
 */
#define CPC_OVR_HW 0x80

/* Size of the "struct ems_cpc_msg" without the union */
#define CPC_MSG_HEADER_LEN   11
#define CPC_CAN_MSG_MIN_SIZE 5

/* Define these values to match your devices */
#define USB_CPCUSB_VENDOR_ID 0x12D6

#define USB_CPCUSB_ARM7_PRODUCT_ID 0x0444

/* Mode register NXP LPC2119/SJA1000 CAN Controller */
#define SJA1000_MOD_NORMAL 0x00
#define SJA1000_MOD_RM     0x01

/* ECC register NXP LPC2119/SJA1000 CAN Controller */
#define SJA1000_ECC_SEG   0x1F
#define SJA1000_ECC_DIR   0x20
#define SJA1000_ECC_ERR   0x06
#define SJA1000_ECC_BIT   0x00
#define SJA1000_ECC_FORM  0x40
#define SJA1000_ECC_STUFF 0x80
#define SJA1000_ECC_MASK  0xc0

/* Status register content */
#define SJA1000_SR_BS 0x80
#define SJA1000_SR_ES 0x40

#define SJA1000_DEFAULT_OUTPUT_CONTROL 0xDA

/*
 * The device actually uses a 16MHz clock to generate the CAN clock
 * but it expects SJA1000 bit settings based on 8MHz (is internally
 * converted).
 */
#define EMS_USB_ARM7_CLOCK 8000000

/*
 * CAN-Message representation in a CPC_MSG. Message object type is
 * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 */
struct cpc_can_msg {
	u32 id;
	u8 length;
	u8 msg[8];
};

/* Representation of the CAN parameters for the SJA1000 controller */
struct cpc_sja1000_params {
	u8 mode;
	u8 acc_code0;
	u8 acc_code1;
	u8 acc_code2;
	u8 acc_code3;
	u8 acc_mask0;
	u8 acc_mask1;
	u8 acc_mask2;
	u8 acc_mask3;
	u8 btr0;
	u8 btr1;
	u8 outp_contr;
};

/* CAN params message representation */
struct cpc_can_params {
	u8 cc_type;

	/* Will support M16C CAN controller in the future */
	union {
		struct cpc_sja1000_params sja1000;
	} cc_params;
};

/* Structure for confirmed message handling */
struct cpc_confirm {
	u8 error; /* error code */
};

/* Structure for overrun conditions */
struct cpc_overrun {
	u8 event;
	u8 count;
};

/* SJA1000 CAN errors (compatible to NXP LPC2119) */
struct cpc_sja1000_can_error {
	u8 ecc;
	u8 rxerr;
	u8 txerr;
};

/* structure for CAN error conditions */
struct cpc_can_error {
	u8 ecode;

	struct {
		u8 cc_type;

		/* Other controllers may also provide error code capture regs */
		union {
			struct cpc_sja1000_can_error sja1000;
		} regs;
	} cc;
};

/*
 * Structure containing RX/TX error counter. This structure is used to request
 * the values of the CAN controllers TX and RX error counter.
 */
struct cpc_can_err_counter {
	u8 rx;
	u8 tx;
};

/* Main message type used between library and application */
struct __attribute__ ((packed)) ems_cpc_msg {