1/*
   2 * CAN driver for EMS Dr. Thomas Wuensche CPC-USB/ARM7
   3 *
   4 * Copyright (C) 2004-2009 EMS Dr. Thomas Wuensche
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms of the GNU General Public License as published
   8 * by the Free Software Foundation; version 2 of the License.
   9 *
  10 * This program is distributed in the hope that it will be useful, but
  11 * WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 * General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License along
  16 * with this program; if not, write to the Free Software Foundation, Inc.,
  17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19#include <linux/signal.h>
  20#include <linux/slab.h>
  21#include <linux/module.h>
  22#include <linux/netdevice.h>
  23#include <linux/usb.h>
  24
  25#include <linux/can.h>
  26#include <linux/can/dev.h>
  27#include <linux/can/error.h>
  28
  29MODULE_AUTHOR("Sebastian Haas <haas@ems-wuensche.com>");
  30MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
  31MODULE_LICENSE("GPL v2");
  32
  33/* Control-Values for CPC_Control() Command Subject Selection */
  34#define CONTR_CAN_MESSAGE 0x04
  35#define CONTR_CAN_STATE   0x0C
  36#define CONTR_BUS_ERROR   0x1C
  37
  38/* Control Command Actions */
  39#define CONTR_CONT_OFF 0
  40#define CONTR_CONT_ON  1
  41#define CONTR_ONCE     2
  42
  43/* Messages from CPC to PC */
  44#define CPC_MSG_TYPE_CAN_FRAME       1  /* CAN data frame */
  45#define CPC_MSG_TYPE_RTR_FRAME       8  /* CAN remote frame */
  46#define CPC_MSG_TYPE_CAN_PARAMS      12 /* Actual CAN parameters */
  47#define CPC_MSG_TYPE_CAN_STATE       14 /* CAN state message */
  48#define CPC_MSG_TYPE_EXT_CAN_FRAME   16 /* Extended CAN data frame */
  49#define CPC_MSG_TYPE_EXT_RTR_FRAME   17 /* Extended remote frame */
  50#define CPC_MSG_TYPE_CONTROL         19 /* change interface behavior */
  51#define CPC_MSG_TYPE_CONFIRM         20 /* command processed confirmation */
  52#define CPC_MSG_TYPE_OVERRUN         21 /* overrun events */
  53#define CPC_MSG_TYPE_CAN_FRAME_ERROR 23 /* detected bus errors */
  54#define CPC_MSG_TYPE_ERR_COUNTER     25 /* RX/TX error counter */
  55
  56/* Messages from the PC to the CPC interface  */
  57#define CPC_CMD_TYPE_CAN_FRAME     1   /* CAN data frame */
  58#define CPC_CMD_TYPE_CONTROL       3   /* control of interface behavior */
  59#define CPC_CMD_TYPE_CAN_PARAMS    6   /* set CAN parameters */
  60#define CPC_CMD_TYPE_RTR_FRAME     13  /* CAN remote frame */
  61#define CPC_CMD_TYPE_CAN_STATE     14  /* CAN state message */
  62#define CPC_CMD_TYPE_EXT_CAN_FRAME 15  /* Extended CAN data frame */
  63#define CPC_CMD_TYPE_EXT_RTR_FRAME 16  /* Extended CAN remote frame */
  64#define CPC_CMD_TYPE_CAN_EXIT      200 /* exit the CAN */
  65
  66#define CPC_CMD_TYPE_INQ_ERR_COUNTER 25 /* request the CAN error counters */
  67#define CPC_CMD_TYPE_CLEAR_MSG_QUEUE 8  /* clear CPC_MSG queue */
  68#define CPC_CMD_TYPE_CLEAR_CMD_QUEUE 28 /* clear CPC_CMD queue */
  69
  70#define CPC_CC_TYPE_SJA1000 2 /* Philips basic CAN controller */
  71
  72#define CPC_CAN_ECODE_ERRFRAME 0x01 /* Ecode type */
  73
  74/* Overrun types */
  75#define CPC_OVR_EVENT_CAN       0x01
  76#define CPC_OVR_EVENT_CANSTATE  0x02
  77#define CPC_OVR_EVENT_BUSERROR  0x04
  78
  79/*
  80 * If the CAN controller lost a message we indicate it with the highest bit
  81 * set in the count field.
  82 */
  83#define CPC_OVR_HW 0x80
  84
  85/* Size of the "struct ems_cpc_msg" without the union */
  86#define CPC_MSG_HEADER_LEN   11
  87#define CPC_CAN_MSG_MIN_SIZE 5
  88
  89/* Define these values to match your devices */
  90#define USB_CPCUSB_VENDOR_ID 0x12D6
  91
  92#define USB_CPCUSB_ARM7_PRODUCT_ID 0x0444
  93
  94/* Mode register NXP LPC2119/SJA1000 CAN Controller */
  95#define SJA1000_MOD_NORMAL 0x00
  96#define SJA1000_MOD_RM     0x01
  97
  98/* ECC register NXP LPC2119/SJA1000 CAN Controller */
  99#define SJA1000_ECC_SEG   0x1F
 100#define SJA1000_ECC_DIR   0x20
 101#define SJA1000_ECC_ERR   0x06
 102#define SJA1000_ECC_BIT   0x00
 103#define SJA1000_ECC_FORM  0x40
 104#define SJA1000_ECC_STUFF 0x80
 105#define SJA1000_ECC_MASK  0xc0
 106
 107/* Status register content */
 108#define SJA1000_SR_BS 0x80
 109#define SJA1000_SR_ES 0x40
 110
 111#define SJA1000_DEFAULT_OUTPUT_CONTROL 0xDA
 112
 113/*
 114 * The device actually uses a 16MHz clock to generate the CAN clock
 115 * but it expects SJA1000 bit settings based on 8MHz (is internally
 116 * converted).
 117 */
 118#define EMS_USB_ARM7_CLOCK 8000000
 119
 120#define CPC_TX_QUEUE_TRIGGER_LOW	25
 121#define CPC_TX_QUEUE_TRIGGER_HIGH	35
 122
 123/*
 124 * CAN-Message representation in a CPC_MSG. Message object type is
 125 * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 126 * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 127 */
 128struct cpc_can_msg {
 129	__le32 id;
 130	u8 length;
 131	u8 msg[8];
 132};
 133
 134/* Representation of the CAN parameters for the SJA1000 controller */
 135struct cpc_sja1000_params {
 136	u8 mode;
 137	u8 acc_code0;
 138	u8 acc_code1;
 139	u8 acc_code2;
 140	u8 acc_code3;
 141	u8 acc_mask0;
 142	u8 acc_mask1;
 143	u8 acc_mask2;
 144	u8 acc_mask3;
 145	u8 btr0;
 146	u8 btr1;
 147	u8 outp_contr;
 148};
 149
 150/* CAN params message representation */
 151struct cpc_can_params {
 152	u8 cc_type;
 153
 154	/* Will support M16C CAN controller in the future */
 155	union {
 156		struct cpc_sja1000_params sja1000;
 157	} cc_params;
 158};
 159
 160/* Structure for confirmed message handling */
 161struct cpc_confirm {
 162	u8 error; /* error code */
 163};
 164
 165/* Structure for overrun conditions */
 166struct cpc_overrun {
 167	u8 event;
 168	u8 count;
 169};
 170
 171/* SJA1000 CAN errors (compatible to NXP LPC2119) */
 172struct cpc_sja1000_can_error {
 173	u8 ecc;
 174	u8 rxerr;
 175	u8 txerr;
 176};
 177
 178/* structure for CAN error conditions */
 179struct cpc_can_error {
 180	u8 ecode;
 181
 182	struct {
 183		u8 cc_type;
 184
 185		/* Other controllers may also provide error code capture regs */
 186		union {
 187			struct cpc_sja1000_can_error sja1000;
 188		} regs;
 189	} cc;
 190};
 191
 192/*
 193 * Structure containing RX/TX error counter. This structure is used to request
 194 * the values of the CAN controllers TX and RX error counter.
 195 */
 196struct cpc_can_err_counter {
 197	u8 rx;
 198	u8 tx;
 199};
 200
 201/* Main message type used between library and application */
 202struct __packed ems_cpc_msg {
 203	u8 type;	/* type of message */
 204	u8 length;	/* length of data within union 'msg' */
 205	u8 msgid;	/* confirmation handle */
 206	__le32 ts_sec;	/* timestamp in seconds */
 207	__le32 ts_nsec;	/* timestamp in nano seconds */
 208
 209	union {
 210		u8 generic[64];
 211		struct cpc_can_msg can_msg;
 212		struct cpc_can_params can_params;
 213		struct cpc_confirm confirmation;
 214		struct cpc_overrun overrun;
 215		struct cpc_can_error error;
 216		struct cpc_can_err_counter err_counter;
 217		u8 can_state;
 218	} msg;
 219};
 220
 221/*
 222 * Table of devices that work with this driver
 223 * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
 224 */
 225static struct usb_device_id ems_usb_table[] = {
 226	{USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 227	{} /* Terminating entry */
 228};
 229
 230MODULE_DEVICE_TABLE(usb, ems_usb_table);
 231
 232#define RX_BUFFER_SIZE      64
 233#define CPC_HEADER_SIZE     4
 234#define INTR_IN_BUFFER_SIZE 4
 235
 236#define MAX_RX_URBS 10
 237#define MAX_TX_URBS 10
 238
 239struct ems_usb;
 240
 241struct ems_tx_urb_context {
 242	struct ems_usb *dev;
 243
 244	u32 echo_index;
 245	u8 dlc;
 246};
 247
 248struct ems_usb {
 249	struct can_priv can; /* must be the first member */
 250
 251	struct sk_buff *echo_skb[MAX_TX_URBS];
 252
 253	struct usb_device *udev;
 254	struct net_device *netdev;
 255
 256	atomic_t active_tx_urbs;
 257	struct usb_anchor tx_submitted;
 258	struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 259
 260	struct usb_anchor rx_submitted;
 261
 262	struct urb *intr_urb;
 263
 264	u8 *tx_msg_buffer;
 265
 266	u8 *intr_in_buffer;
 267	unsigned int free_slots; /* remember number of available slots */
 268
 269	struct ems_cpc_msg active_params; /* active controller parameters */
 270};
 271
 272static void ems_usb_read_interrupt_callback(struct urb *urb)
 273{
 274	struct ems_usb *dev = urb->context;
 275	struct net_device *netdev = dev->netdev;
 276	int err;
 277
 278	if (!netif_device_present(netdev))
 279		return;
 280
 281	switch (urb->status) {
 282	case 0:
 283		dev->free_slots = dev->intr_in_buffer[1];
 284		if (dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH &&
 285		    netif_queue_stopped(netdev))
 286			netif_wake_queue(netdev);
 287		break;
 288
 289	case -ECONNRESET: /* unlink */
 290	case -ENOENT:
 291	case -EPIPE:
 292	case -EPROTO:
 293	case -ESHUTDOWN:
 294		return;
 295
 296	default:
 297		netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
 298		break;
 299	}
 300
 301	err = usb_submit_urb(urb, GFP_ATOMIC);
 302
 303	if (err == -ENODEV)
 304		netif_device_detach(netdev);
 305	else if (err)
 306		netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
 307}
 308
 309static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 310{
 311	struct can_frame *cf;
 312	struct sk_buff *skb;
 313	int i;
 314	struct net_device_stats *stats = &dev->netdev->stats;
 315
 316	skb = alloc_can_skb(dev->netdev, &cf);
 317	if (skb == NULL)
 318		return;
 319
 320	cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 321	cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
 322
 323	if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 324	    msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 325		cf->can_id |= CAN_EFF_FLAG;
 326
 327	if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 328	    msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 329		cf->can_id |= CAN_RTR_FLAG;
 330	} else {
 331		for (i = 0; i < cf->can_dlc; i++)
 332			cf->data[i] = msg->msg.can_msg.msg[i];
 333	}
 334
 335	stats->rx_packets++;
 336	stats->rx_bytes += cf->can_dlc;
 337	netif_rx(skb);
 338}
 339
 340static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 341{
 342	struct can_frame *cf;
 343	struct sk_buff *skb;
 344	struct net_device_stats *stats = &dev->netdev->stats;
 345
 346	skb = alloc_can_err_skb(dev->netdev, &cf);
 347	if (skb == NULL)
 348		return;
 349
 350	if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 351		u8 state = msg->msg.can_state;
 352
 353		if (state & SJA1000_SR_BS) {
 354			dev->can.state = CAN_STATE_BUS_OFF;
 355			cf->can_id |= CAN_ERR_BUSOFF;
 356
 357			dev->can.can_stats.bus_off++;
 358			can_bus_off(dev->netdev);
 359		} else if (state & SJA1000_SR_ES) {
 360			dev->can.state = CAN_STATE_ERROR_WARNING;
 361			dev->can.can_stats.error_warning++;
 362		} else {
 363			dev->can.state = CAN_STATE_ERROR_ACTIVE;
 364			dev->can.can_stats.error_passive++;
 365		}
 366	} else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 367		u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 368		u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 369		u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 370
 371		/* bus error interrupt */
 372		dev->can.can_stats.bus_error++;
 373		stats->rx_errors++;
 374
 375		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 376
 377		switch (ecc & SJA1000_ECC_MASK) {
 378		case SJA1000_ECC_BIT:
 379			cf->data[2] |= CAN_ERR_PROT_BIT;
 380			break;
 381		case SJA1000_ECC_FORM:
 382			cf->data[2] |= CAN_ERR_PROT_FORM;
 383			break;
 384		case SJA1000_ECC_STUFF:
 385			cf->data[2] |= CAN_ERR_PROT_STUFF;
 386			break;
 387		default:
 388			cf->data[3] = ecc & SJA1000_ECC_SEG;
 389			break;
 390		}
 391
 392		/* Error occurred during transmission? */
 393		if ((ecc & SJA1000_ECC_DIR) == 0)
 394			cf->data[2] |= CAN_ERR_PROT_TX;
 395
 396		if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 397		    dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 398			cf->can_id |= CAN_ERR_CRTL;
 399			cf->data[1] = (txerr > rxerr) ?
 400			    CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 401		}
 402	} else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 403		cf->can_id |= CAN_ERR_CRTL;
 404		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 405
 406		stats->rx_over_errors++;
 407		stats->rx_errors++;
 408	}
 409
 410	stats->rx_packets++;
 411	stats->rx_bytes += cf->can_dlc;
 412	netif_rx(skb);
 413}
 414
 415/*
 416 * callback for bulk IN urb
 417 */
 418static void ems_usb_read_bulk_callback(struct urb *urb)
 419{
 420	struct ems_usb *dev = urb->context;
 421	struct net_device *netdev;
 422	int retval;
 423
 424	netdev = dev->netdev;
 425
 426	if (!netif_device_present(netdev))
 427		return;
 428
 429	switch (urb->status) {
 430	case 0: /* success */
 431		break;
 432
 433	case -ENOENT:
 434		return;
 435
 436	default:
 437		netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 438		goto resubmit_urb;
 439	}
 440
 441	if (urb->actual_length > CPC_HEADER_SIZE) {
 442		struct ems_cpc_msg *msg;
 443		u8 *ibuf = urb->transfer_buffer;
 444		u8 msg_count, start;
 445
 446		msg_count = ibuf[0] & ~0x80;
 447
 448		start = CPC_HEADER_SIZE;
 449
 450		while (msg_count) {
 451			msg = (struct ems_cpc_msg *)&ibuf[start];
 452
 453			switch (msg->type) {
 454			case CPC_MSG_TYPE_CAN_STATE:
 455				/* Process CAN state changes */
 456				ems_usb_rx_err(dev, msg);
 457				break;
 458
 459			case CPC_MSG_TYPE_CAN_FRAME:
 460			case CPC_MSG_TYPE_EXT_CAN_FRAME:
 461			case CPC_MSG_TYPE_RTR_FRAME:
 462			case CPC_MSG_TYPE_EXT_RTR_FRAME:
 463				ems_usb_rx_can_msg(dev, msg);
 464				break;
 465
 466			case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 467				/* Process errorframe */
 468				ems_usb_rx_err(dev, msg);
 469				break;
 470
 471			case CPC_MSG_TYPE_OVERRUN:
 472				/* Message lost while receiving */
 473				ems_usb_rx_err(dev, msg);
 474				break;
 475			}
 476
 477			start += CPC_MSG_HEADER_LEN + msg->length;
 478			msg_count--;
 479
 480			if (start > urb->transfer_buffer_length) {
 481				netdev_err(netdev, "format error\n");
 482				break;
 483			}
 484		}
 485	}
 486
 487resubmit_urb:
 488	usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 489			  urb->transfer_buffer, RX_BUFFER_SIZE,
 490			  ems_usb_read_bulk_callback, dev);
 491
 492	retval = usb_submit_urb(urb, GFP_ATOMIC);
 493
 494	if (retval == -ENODEV)
 495		netif_device_detach(netdev);
 496	else if (retval)
 497		netdev_err(netdev,
 498			   "failed resubmitting read bulk urb: %d\n", retval);
 499}
 500
 501/*
 502 * callback for bulk IN urb
 503 */
 504static void ems_usb_write_bulk_callback(struct urb *urb)
 505{
 506	struct ems_tx_urb_context *context = urb->context;
 507	struct ems_usb *dev;
 508	struct net_device *netdev;
 509
 510	BUG_ON(!context);
 511
 512	dev = context->dev;
 513	netdev = dev->netdev;
 514
 515	/* free up our allocated buffer */
 516	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 517			  urb->transfer_buffer, urb->transfer_dma);
 518
 519	atomic_dec(&dev->active_tx_urbs);
 520
 521	if (!netif_device_present(netdev))
 522		return;
 523
 524	if (urb->status)
 525		netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
 526
 527	netif_trans_update(netdev);
 528
 529	/* transmission complete interrupt */
 530	netdev->stats.tx_packets++;
 531	netdev->stats.tx_bytes += context->dlc;
 532
 533	can_get_echo_skb(netdev, context->echo_index);
 534
 535	/* Release context */
 536	context->echo_index = MAX_TX_URBS;
 537
 538}
 539
 540/*
 541 * Send the given CPC command synchronously
 542 */
 543static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 544{
 545	int actual_length;
 546
 547	/* Copy payload */
 548	memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 549	       msg->length + CPC_MSG_HEADER_LEN);
 550
 551	/* Clear header */
 552	memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 553
 554	return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 555			    &dev->tx_msg_buffer[0],
 556			    msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 557			    &actual_length, 1000);
 558}
 559
 560/*
 561 * Change CAN controllers' mode register
 562 */
 563static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 564{
 565	dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 566
 567	return ems_usb_command_msg(dev, &dev->active_params);
 568}
 569
 570/*
 571 * Send a CPC_Control command to change behaviour when interface receives a CAN
 572 * message, bus error or CAN state changed notifications.
 573 */
 574static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 575{
 576	struct ems_cpc_msg cmd;
 577
 578	cmd.type = CPC_CMD_TYPE_CONTROL;
 579	cmd.length = CPC_MSG_HEADER_LEN + 1;
 580
 581	cmd.msgid = 0;
 582
 583	cmd.msg.generic[0] = val;
 584
 585	return ems_usb_command_msg(dev, &cmd);
 586}
 587
 588/*
 589 * Start interface
 590 */
 591static int ems_usb_start(struct ems_usb *dev)
 592{
 593	struct net_device *netdev = dev->netdev;
 594	int err, i;
 595
 596	dev->intr_in_buffer[0] = 0;
 597	dev->free_slots = 50; /* initial size */
 598
 599	for (i = 0; i < MAX_RX_URBS; i++) {
 600		struct urb *urb = NULL;
 601		u8 *buf = NULL;
 602
 603		/* create a URB, and a buffer for it */
 604		urb = usb_alloc_urb(0, GFP_KERNEL);
 605		if (!urb) {
 
 606			err = -ENOMEM;
 607			break;
 608		}
 609
 610		buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 611					 &urb->transfer_dma);
 612		if (!buf) {
 613			netdev_err(netdev, "No memory left for USB buffer\n");
 614			usb_free_urb(urb);
 615			err = -ENOMEM;
 616			break;
 617		}
 618
 619		usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 620				  buf, RX_BUFFER_SIZE,
 621				  ems_usb_read_bulk_callback, dev);
 622		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 623		usb_anchor_urb(urb, &dev->rx_submitted);
 624
 625		err = usb_submit_urb(urb, GFP_KERNEL);
 626		if (err) {
 627			usb_unanchor_urb(urb);
 628			usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 629					  urb->transfer_dma);
 630			usb_free_urb(urb);
 631			break;
 632		}
 633
 634		/* Drop reference, USB core will take care of freeing it */
 635		usb_free_urb(urb);
 636	}
 637
 638	/* Did we submit any URBs */
 639	if (i == 0) {
 640		netdev_warn(netdev, "couldn't setup read URBs\n");
 641		return err;
 642	}
 643
 644	/* Warn if we've couldn't transmit all the URBs */
 645	if (i < MAX_RX_URBS)
 646		netdev_warn(netdev, "rx performance may be slow\n");
 647
 648	/* Setup and start interrupt URB */
 649	usb_fill_int_urb(dev->intr_urb, dev->udev,
 650			 usb_rcvintpipe(dev->udev, 1),
 651			 dev->intr_in_buffer,
 652			 INTR_IN_BUFFER_SIZE,
 653			 ems_usb_read_interrupt_callback, dev, 1);
 654
 655	err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 656	if (err) {
 657		netdev_warn(netdev, "intr URB submit failed: %d\n", err);
 658
 659		return err;
 660	}
 661
 662	/* CPC-USB will transfer received message to host */
 663	err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 664	if (err)
 665		goto failed;
 666
 667	/* CPC-USB will transfer CAN state changes to host */
 668	err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 669	if (err)
 670		goto failed;
 671
 672	/* CPC-USB will transfer bus errors to host */
 673	err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 674	if (err)
 675		goto failed;
 676
 677	err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 678	if (err)
 679		goto failed;
 680
 681	dev->can.state = CAN_STATE_ERROR_ACTIVE;
 682
 683	return 0;
 684
 685failed:
 686	netdev_warn(netdev, "couldn't submit control: %d\n", err);
 687
 688	return err;
 689}
 690
 691static void unlink_all_urbs(struct ems_usb *dev)
 692{
 693	int i;
 694
 695	usb_unlink_urb(dev->intr_urb);
 696
 697	usb_kill_anchored_urbs(&dev->rx_submitted);
 698
 699	usb_kill_anchored_urbs(&dev->tx_submitted);
 700	atomic_set(&dev->active_tx_urbs, 0);
 701
 702	for (i = 0; i < MAX_TX_URBS; i++)
 703		dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 704}
 705
 706static int ems_usb_open(struct net_device *netdev)
 707{
 708	struct ems_usb *dev = netdev_priv(netdev);
 709	int err;
 710
 711	err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 712	if (err)
 713		return err;
 714
 715	/* common open */
 716	err = open_candev(netdev);
 717	if (err)
 718		return err;
 719
 720	/* finally start device */
 721	err = ems_usb_start(dev);
 722	if (err) {
 723		if (err == -ENODEV)
 724			netif_device_detach(dev->netdev);
 725
 726		netdev_warn(netdev, "couldn't start device: %d\n", err);
 727
 728		close_candev(netdev);
 729
 730		return err;
 731	}
 732
 733
 734	netif_start_queue(netdev);
 735
 736	return 0;
 737}
 738
 739static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 740{
 741	struct ems_usb *dev = netdev_priv(netdev);
 742	struct ems_tx_urb_context *context = NULL;
 743	struct net_device_stats *stats = &netdev->stats;
 744	struct can_frame *cf = (struct can_frame *)skb->data;
 745	struct ems_cpc_msg *msg;
 746	struct urb *urb;
 747	u8 *buf;
 748	int i, err;
 749	size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 750			+ sizeof(struct cpc_can_msg);
 751
 752	if (can_dropped_invalid_skb(netdev, skb))
 753		return NETDEV_TX_OK;
 754
 755	/* create a URB, and a buffer for it, and copy the data to the URB */
 756	urb = usb_alloc_urb(0, GFP_ATOMIC);
 757	if (!urb)
 
 758		goto nomem;
 
 759
 760	buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 761	if (!buf) {
 762		netdev_err(netdev, "No memory left for USB buffer\n");
 763		usb_free_urb(urb);
 764		goto nomem;
 765	}
 766
 767	msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 768
 769	msg->msg.can_msg.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
 770	msg->msg.can_msg.length = cf->can_dlc;
 771
 772	if (cf->can_id & CAN_RTR_FLAG) {
 773		msg->type = cf->can_id & CAN_EFF_FLAG ?
 774			CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 775
 776		msg->length = CPC_CAN_MSG_MIN_SIZE;
 777	} else {
 778		msg->type = cf->can_id & CAN_EFF_FLAG ?
 779			CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 780
 781		for (i = 0; i < cf->can_dlc; i++)
 782			msg->msg.can_msg.msg[i] = cf->data[i];
 783
 784		msg->length = CPC_CAN_MSG_MIN_SIZE + cf->can_dlc;
 785	}
 786
 787	for (i = 0; i < MAX_TX_URBS; i++) {
 788		if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 789			context = &dev->tx_contexts[i];
 790			break;
 791		}
 792	}
 793
 794	/*
 795	 * May never happen! When this happens we'd more URBs in flight as
 796	 * allowed (MAX_TX_URBS).
 797	 */
 798	if (!context) {
 799		usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 800		usb_free_urb(urb);
 801
 802		netdev_warn(netdev, "couldn't find free context\n");
 803
 804		return NETDEV_TX_BUSY;
 805	}
 806
 807	context->dev = dev;
 808	context->echo_index = i;
 809	context->dlc = cf->can_dlc;
 810
 811	usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 812			  size, ems_usb_write_bulk_callback, context);
 813	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 814	usb_anchor_urb(urb, &dev->tx_submitted);
 815
 816	can_put_echo_skb(skb, netdev, context->echo_index);
 817
 818	atomic_inc(&dev->active_tx_urbs);
 819
 820	err = usb_submit_urb(urb, GFP_ATOMIC);
 821	if (unlikely(err)) {
 822		can_free_echo_skb(netdev, context->echo_index);
 823
 824		usb_unanchor_urb(urb);
 825		usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 826		dev_kfree_skb(skb);
 827
 828		atomic_dec(&dev->active_tx_urbs);
 829
 830		if (err == -ENODEV) {
 831			netif_device_detach(netdev);
 832		} else {
 833			netdev_warn(netdev, "failed tx_urb %d\n", err);
 834
 835			stats->tx_dropped++;
 836		}
 837	} else {
 838		netif_trans_update(netdev);
 839
 840		/* Slow down tx path */
 841		if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 842		    dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
 843			netif_stop_queue(netdev);
 844		}
 845	}
 846
 847	/*
 848	 * Release our reference to this URB, the USB core will eventually free
 849	 * it entirely.
 850	 */
 851	usb_free_urb(urb);
 852
 853	return NETDEV_TX_OK;
 854
 855nomem:
 856	dev_kfree_skb(skb);
 857	stats->tx_dropped++;
 858
 859	return NETDEV_TX_OK;
 860}
 861
 862static int ems_usb_close(struct net_device *netdev)
 863{
 864	struct ems_usb *dev = netdev_priv(netdev);
 865
 866	/* Stop polling */
 867	unlink_all_urbs(dev);
 868
 869	netif_stop_queue(netdev);
 870
 871	/* Set CAN controller to reset mode */
 872	if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 873		netdev_warn(netdev, "couldn't stop device");
 874
 875	close_candev(netdev);
 876
 877	return 0;
 878}
 879
 880static const struct net_device_ops ems_usb_netdev_ops = {
 881	.ndo_open = ems_usb_open,
 882	.ndo_stop = ems_usb_close,
 883	.ndo_start_xmit = ems_usb_start_xmit,
 884	.ndo_change_mtu = can_change_mtu,
 885};
 886
 887static const struct can_bittiming_const ems_usb_bittiming_const = {
 888	.name = "ems_usb",
 889	.tseg1_min = 1,
 890	.tseg1_max = 16,
 891	.tseg2_min = 1,
 892	.tseg2_max = 8,
 893	.sjw_max = 4,
 894	.brp_min = 1,
 895	.brp_max = 64,
 896	.brp_inc = 1,
 897};
 898
 899static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 900{
 901	struct ems_usb *dev = netdev_priv(netdev);
 902
 903	switch (mode) {
 904	case CAN_MODE_START:
 905		if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 906			netdev_warn(netdev, "couldn't start device");
 907
 908		if (netif_queue_stopped(netdev))
 909			netif_wake_queue(netdev);
 910		break;
 911
 912	default:
 913		return -EOPNOTSUPP;
 914	}
 915
 916	return 0;
 917}
 918
 919static int ems_usb_set_bittiming(struct net_device *netdev)
 920{
 921	struct ems_usb *dev = netdev_priv(netdev);
 922	struct can_bittiming *bt = &dev->can.bittiming;
 923	u8 btr0, btr1;
 924
 925	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 926	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 927		(((bt->phase_seg2 - 1) & 0x7) << 4);
 928	if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 929		btr1 |= 0x80;
 930
 931	netdev_info(netdev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
 932
 933	dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 934	dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 935
 936	return ems_usb_command_msg(dev, &dev->active_params);
 937}
 938
 939static void init_params_sja1000(struct ems_cpc_msg *msg)
 940{
 941	struct cpc_sja1000_params *sja1000 =
 942		&msg->msg.can_params.cc_params.sja1000;
 943
 944	msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 945	msg->length = sizeof(struct cpc_can_params);
 946	msg->msgid = 0;
 947
 948	msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 949
 950	/* Acceptance filter open */
 951	sja1000->acc_code0 = 0x00;
 952	sja1000->acc_code1 = 0x00;
 953	sja1000->acc_code2 = 0x00;
 954	sja1000->acc_code3 = 0x00;
 955
 956	/* Acceptance filter open */
 957	sja1000->acc_mask0 = 0xFF;
 958	sja1000->acc_mask1 = 0xFF;
 959	sja1000->acc_mask2 = 0xFF;
 960	sja1000->acc_mask3 = 0xFF;
 961
 962	sja1000->btr0 = 0;
 963	sja1000->btr1 = 0;
 964
 965	sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 966	sja1000->mode = SJA1000_MOD_RM;
 967}
 968
 969/*
 970 * probe function for new CPC-USB devices
 971 */
 972static int ems_usb_probe(struct usb_interface *intf,
 973			 const struct usb_device_id *id)
 974{
 975	struct net_device *netdev;
 976	struct ems_usb *dev;
 977	int i, err = -ENOMEM;
 978
 979	netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
 980	if (!netdev) {
 981		dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
 982		return -ENOMEM;
 983	}
 984
 985	dev = netdev_priv(netdev);
 986
 987	dev->udev = interface_to_usbdev(intf);
 988	dev->netdev = netdev;
 989
 990	dev->can.state = CAN_STATE_STOPPED;
 991	dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
 992	dev->can.bittiming_const = &ems_usb_bittiming_const;
 993	dev->can.do_set_bittiming = ems_usb_set_bittiming;
 994	dev->can.do_set_mode = ems_usb_set_mode;
 995	dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
 996
 997	netdev->netdev_ops = &ems_usb_netdev_ops;
 998
 999	netdev->flags |= IFF_ECHO; /* we support local echo */
1000
1001	init_usb_anchor(&dev->rx_submitted);
1002
1003	init_usb_anchor(&dev->tx_submitted);
1004	atomic_set(&dev->active_tx_urbs, 0);
1005
1006	for (i = 0; i < MAX_TX_URBS; i++)
1007		dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1008
1009	dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1010	if (!dev->intr_urb)
 
1011		goto cleanup_candev;
 
1012
1013	dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1014	if (!dev->intr_in_buffer)
1015		goto cleanup_intr_urb;
1016
1017	dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1018				     sizeof(struct ems_cpc_msg), GFP_KERNEL);
1019	if (!dev->tx_msg_buffer)
1020		goto cleanup_intr_in_buffer;
1021
1022	usb_set_intfdata(intf, dev);
1023
1024	SET_NETDEV_DEV(netdev, &intf->dev);
1025
1026	init_params_sja1000(&dev->active_params);
1027
1028	err = ems_usb_command_msg(dev, &dev->active_params);
1029	if (err) {
1030		netdev_err(netdev, "couldn't initialize controller: %d\n", err);
1031		goto cleanup_tx_msg_buffer;
1032	}
1033
1034	err = register_candev(netdev);
1035	if (err) {
1036		netdev_err(netdev, "couldn't register CAN device: %d\n", err);
1037		goto cleanup_tx_msg_buffer;
1038	}
1039
1040	return 0;
1041
1042cleanup_tx_msg_buffer:
1043	kfree(dev->tx_msg_buffer);
1044
1045cleanup_intr_in_buffer:
1046	kfree(dev->intr_in_buffer);
1047
1048cleanup_intr_urb:
1049	usb_free_urb(dev->intr_urb);
1050
1051cleanup_candev:
1052	free_candev(netdev);
1053
1054	return err;
1055}
1056
1057/*
1058 * called by the usb core when the device is removed from the system
1059 */
1060static void ems_usb_disconnect(struct usb_interface *intf)
1061{
1062	struct ems_usb *dev = usb_get_intfdata(intf);
1063
1064	usb_set_intfdata(intf, NULL);
1065
1066	if (dev) {
1067		unregister_netdev(dev->netdev);
1068		free_candev(dev->netdev);
1069
1070		unlink_all_urbs(dev);
1071
1072		usb_free_urb(dev->intr_urb);
1073
1074		kfree(dev->intr_in_buffer);
1075	}
1076}
1077
1078/* usb specific object needed to register this driver with the usb subsystem */
1079static struct usb_driver ems_usb_driver = {
1080	.name = "ems_usb",
1081	.probe = ems_usb_probe,
1082	.disconnect = ems_usb_disconnect,
1083	.id_table = ems_usb_table,
1084};
1085
1086module_usb_driver(ems_usb_driver);