c_can.c revision d9cb9bd63eb27ac19f26a8547128c053f43a5da8
1/* 2 * CAN bus driver for Bosch C_CAN controller 3 * 4 * Copyright (C) 2010 ST Microelectronics 5 * Bhupesh Sharma <bhupesh.sharma@st.com> 6 * 7 * Borrowed heavily from the C_CAN driver originally written by: 8 * Copyright (C) 2007 9 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de> 10 * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch> 11 * 12 * TX and RX NAPI implementation has been borrowed from at91 CAN driver 13 * written by: 14 * Copyright 15 * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de> 16 * (C) 2008, 2009 by Marc Kleine-Budde <kernel@pengutronix.de> 17 * 18 * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B. 19 * Bosch C_CAN user manual can be obtained from: 20 * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/ 21 * users_manual_c_can.pdf 22 * 23 * This file is licensed under the terms of the GNU General Public 24 * License version 2. This program is licensed "as is" without any 25 * warranty of any kind, whether express or implied. 26 */ 27 28#include <linux/kernel.h> 29#include <linux/module.h> 30#include <linux/interrupt.h> 31#include <linux/delay.h> 32#include <linux/netdevice.h> 33#include <linux/if_arp.h> 34#include <linux/if_ether.h> 35#include <linux/list.h> 36#include <linux/io.h> 37 38#include <linux/can.h> 39#include <linux/can/dev.h> 40#include <linux/can/error.h> 41 42#include "c_can.h" 43 44/* control register */ 45#define CONTROL_TEST BIT(7) 46#define CONTROL_CCE BIT(6) 47#define CONTROL_DISABLE_AR BIT(5) 48#define CONTROL_ENABLE_AR (0 << 5) 49#define CONTROL_EIE BIT(3) 50#define CONTROL_SIE BIT(2) 51#define CONTROL_IE BIT(1) 52#define CONTROL_INIT BIT(0) 53 54/* test register */ 55#define TEST_RX BIT(7) 56#define TEST_TX1 BIT(6) 57#define TEST_TX2 BIT(5) 58#define TEST_LBACK BIT(4) 59#define TEST_SILENT BIT(3) 60#define TEST_BASIC BIT(2) 61 62/* status register */ 63#define STATUS_BOFF BIT(7) 64#define STATUS_EWARN BIT(6) 65#define STATUS_EPASS BIT(5) 66#define STATUS_RXOK BIT(4) 67#define STATUS_TXOK BIT(3) 68 69/* error counter register */ 70#define ERR_CNT_TEC_MASK 0xff 71#define ERR_CNT_TEC_SHIFT 0 72#define ERR_CNT_REC_SHIFT 8 73#define ERR_CNT_REC_MASK (0x7f << ERR_CNT_REC_SHIFT) 74#define ERR_CNT_RP_SHIFT 15 75#define ERR_CNT_RP_MASK (0x1 << ERR_CNT_RP_SHIFT) 76 77/* bit-timing register */ 78#define BTR_BRP_MASK 0x3f 79#define BTR_BRP_SHIFT 0 80#define BTR_SJW_SHIFT 6 81#define BTR_SJW_MASK (0x3 << BTR_SJW_SHIFT) 82#define BTR_TSEG1_SHIFT 8 83#define BTR_TSEG1_MASK (0xf << BTR_TSEG1_SHIFT) 84#define BTR_TSEG2_SHIFT 12 85#define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT) 86 87/* brp extension register */ 88#define BRP_EXT_BRPE_MASK 0x0f 89#define BRP_EXT_BRPE_SHIFT 0 90 91/* IFx command request */ 92#define IF_COMR_BUSY BIT(15) 93 94/* IFx command mask */ 95#define IF_COMM_WR BIT(7) 96#define IF_COMM_MASK BIT(6) 97#define IF_COMM_ARB BIT(5) 98#define IF_COMM_CONTROL BIT(4) 99#define IF_COMM_CLR_INT_PND BIT(3) 100#define IF_COMM_TXRQST BIT(2) 101#define IF_COMM_DATAA BIT(1) 102#define IF_COMM_DATAB BIT(0) 103#define IF_COMM_ALL (IF_COMM_MASK | IF_COMM_ARB | \ 104 IF_COMM_CONTROL | IF_COMM_TXRQST | \ 105 IF_COMM_DATAA | IF_COMM_DATAB) 106 107/* IFx arbitration */ 108#define IF_ARB_MSGVAL BIT(15) 109#define IF_ARB_MSGXTD BIT(14) 110#define IF_ARB_TRANSMIT BIT(13) 111 112/* IFx message control */ 113#define IF_MCONT_NEWDAT BIT(15) 114#define IF_MCONT_MSGLST BIT(14) 115#define IF_MCONT_CLR_MSGLST (0 << 14) 116#define IF_MCONT_INTPND BIT(13) 117#define IF_MCONT_UMASK BIT(12) 118#define IF_MCONT_TXIE BIT(11) 119#define IF_MCONT_RXIE BIT(10) 120#define IF_MCONT_RMTEN BIT(9) 121#define IF_MCONT_TXRQST BIT(8) 122#define IF_MCONT_EOB BIT(7) 123#define IF_MCONT_DLC_MASK 0xf 124 125/* 126 * IFx register masks: 127 * allow easy operation on 16-bit registers when the 128 * argument is 32-bit instead 129 */ 130#define IFX_WRITE_LOW_16BIT(x) ((x) & 0xFFFF) 131#define IFX_WRITE_HIGH_16BIT(x) (((x) & 0xFFFF0000) >> 16) 132 133/* message object split */ 134#define C_CAN_NO_OF_OBJECTS 32 135#define C_CAN_MSG_OBJ_RX_NUM 16 136#define C_CAN_MSG_OBJ_TX_NUM 16 137 138#define C_CAN_MSG_OBJ_RX_FIRST 1 139#define C_CAN_MSG_OBJ_RX_LAST (C_CAN_MSG_OBJ_RX_FIRST + \ 140 C_CAN_MSG_OBJ_RX_NUM - 1) 141 142#define C_CAN_MSG_OBJ_TX_FIRST (C_CAN_MSG_OBJ_RX_LAST + 1) 143#define C_CAN_MSG_OBJ_TX_LAST (C_CAN_MSG_OBJ_TX_FIRST + \ 144 C_CAN_MSG_OBJ_TX_NUM - 1) 145 146#define C_CAN_MSG_OBJ_RX_SPLIT 9 147#define C_CAN_MSG_RX_LOW_LAST (C_CAN_MSG_OBJ_RX_SPLIT - 1) 148 149#define C_CAN_NEXT_MSG_OBJ_MASK (C_CAN_MSG_OBJ_TX_NUM - 1) 150#define RECEIVE_OBJECT_BITS 0x0000ffff 151 152/* status interrupt */ 153#define STATUS_INTERRUPT 0x8000 154 155/* global interrupt masks */ 156#define ENABLE_ALL_INTERRUPTS 1 157#define DISABLE_ALL_INTERRUPTS 0 158 159/* minimum timeout for checking BUSY status */ 160#define MIN_TIMEOUT_VALUE 6 161 162/* napi related */ 163#define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM 164 165/* c_can lec values */ 166enum c_can_lec_type { 167 LEC_NO_ERROR = 0, 168 LEC_STUFF_ERROR, 169 LEC_FORM_ERROR, 170 LEC_ACK_ERROR, 171 LEC_BIT1_ERROR, 172 LEC_BIT0_ERROR, 173 LEC_CRC_ERROR, 174 LEC_UNUSED, 175}; 176 177/* 178 * c_can error types: 179 * Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported 180 */ 181enum c_can_bus_error_types { 182 C_CAN_NO_ERROR = 0, 183 C_CAN_BUS_OFF, 184 C_CAN_ERROR_WARNING, 185 C_CAN_ERROR_PASSIVE, 186}; 187 188static struct can_bittiming_const c_can_bittiming_const = { 189 .name = KBUILD_MODNAME, 190 .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */ 191 .tseg1_max = 16, 192 .tseg2_min = 1, /* Time segment 2 = phase_seg2 */ 193 .tseg2_max = 8, 194 .sjw_max = 4, 195 .brp_min = 1, 196 .brp_max = 1024, /* 6-bit BRP field + 4-bit BRPE field*/ 197 .brp_inc = 1, 198}; 199 200static inline int get_tx_next_msg_obj(const struct c_can_priv *priv) 201{ 202 return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) + 203 C_CAN_MSG_OBJ_TX_FIRST; 204} 205 206static inline int get_tx_echo_msg_obj(const struct c_can_priv *priv) 207{ 208 return (priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) + 209 C_CAN_MSG_OBJ_TX_FIRST; 210} 211 212static u32 c_can_read_reg32(struct c_can_priv *priv, void *reg) 213{ 214 u32 val = priv->read_reg(priv, reg); 215 val |= ((u32) priv->read_reg(priv, reg + 2)) << 16; 216 return val; 217} 218 219static void c_can_enable_all_interrupts(struct c_can_priv *priv, 220 int enable) 221{ 222 unsigned int cntrl_save = priv->read_reg(priv, 223 &priv->regs->control); 224 225 if (enable) 226 cntrl_save |= (CONTROL_SIE | CONTROL_EIE | CONTROL_IE); 227 else 228 cntrl_save &= ~(CONTROL_EIE | CONTROL_IE | CONTROL_SIE); 229 230 priv->write_reg(priv, &priv->regs->control, cntrl_save); 231} 232 233static inline int c_can_msg_obj_is_busy(struct c_can_priv *priv, int iface) 234{ 235 int count = MIN_TIMEOUT_VALUE; 236 237 while (count && priv->read_reg(priv, 238 &priv->regs->ifregs[iface].com_req) & 239 IF_COMR_BUSY) { 240 count--; 241 udelay(1); 242 } 243 244 if (!count) 245 return 1; 246 247 return 0; 248} 249 250static inline void c_can_object_get(struct net_device *dev, 251 int iface, int objno, int mask) 252{ 253 struct c_can_priv *priv = netdev_priv(dev); 254 255 /* 256 * As per specs, after writting the message object number in the 257 * IF command request register the transfer b/w interface 258 * register and message RAM must be complete in 6 CAN-CLK 259 * period. 260 */ 261 priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask, 262 IFX_WRITE_LOW_16BIT(mask)); 263 priv->write_reg(priv, &priv->regs->ifregs[iface].com_req, 264 IFX_WRITE_LOW_16BIT(objno)); 265 266 if (c_can_msg_obj_is_busy(priv, iface)) 267 netdev_err(dev, "timed out in object get\n"); 268} 269 270static inline void c_can_object_put(struct net_device *dev, 271 int iface, int objno, int mask) 272{ 273 struct c_can_priv *priv = netdev_priv(dev); 274 275 /* 276 * As per specs, after writting the message object number in the 277 * IF command request register the transfer b/w interface 278 * register and message RAM must be complete in 6 CAN-CLK 279 * period. 280 */ 281 priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask, 282 (IF_COMM_WR | IFX_WRITE_LOW_16BIT(mask))); 283 priv->write_reg(priv, &priv->regs->ifregs[iface].com_req, 284 IFX_WRITE_LOW_16BIT(objno)); 285 286 if (c_can_msg_obj_is_busy(priv, iface)) 287 netdev_err(dev, "timed out in object put\n"); 288} 289 290static void c_can_write_msg_object(struct net_device *dev, 291 int iface, struct can_frame *frame, int objno) 292{ 293 int i; 294 u16 flags = 0; 295 unsigned int id; 296 struct c_can_priv *priv = netdev_priv(dev); 297 298 if (!(frame->can_id & CAN_RTR_FLAG)) 299 flags |= IF_ARB_TRANSMIT; 300 301 if (frame->can_id & CAN_EFF_FLAG) { 302 id = frame->can_id & CAN_EFF_MASK; 303 flags |= IF_ARB_MSGXTD; 304 } else 305 id = ((frame->can_id & CAN_SFF_MASK) << 18); 306 307 flags |= IF_ARB_MSGVAL; 308 309 priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, 310 IFX_WRITE_LOW_16BIT(id)); 311 priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, flags | 312 IFX_WRITE_HIGH_16BIT(id)); 313 314 for (i = 0; i < frame->can_dlc; i += 2) { 315 priv->write_reg(priv, &priv->regs->ifregs[iface].data[i / 2], 316 frame->data[i] | (frame->data[i + 1] << 8)); 317 } 318 319 /* enable interrupt for this message object */ 320 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 321 IF_MCONT_TXIE | IF_MCONT_TXRQST | IF_MCONT_EOB | 322 frame->can_dlc); 323 c_can_object_put(dev, iface, objno, IF_COMM_ALL); 324} 325 326static inline void c_can_mark_rx_msg_obj(struct net_device *dev, 327 int iface, int ctrl_mask, 328 int obj) 329{ 330 struct c_can_priv *priv = netdev_priv(dev); 331 332 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 333 ctrl_mask & ~(IF_MCONT_MSGLST | IF_MCONT_INTPND)); 334 c_can_object_put(dev, iface, obj, IF_COMM_CONTROL); 335 336} 337 338static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev, 339 int iface, 340 int ctrl_mask) 341{ 342 int i; 343 struct c_can_priv *priv = netdev_priv(dev); 344 345 for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_MSG_RX_LOW_LAST; i++) { 346 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 347 ctrl_mask & ~(IF_MCONT_MSGLST | 348 IF_MCONT_INTPND | IF_MCONT_NEWDAT)); 349 c_can_object_put(dev, iface, i, IF_COMM_CONTROL); 350 } 351} 352 353static inline void c_can_activate_rx_msg_obj(struct net_device *dev, 354 int iface, int ctrl_mask, 355 int obj) 356{ 357 struct c_can_priv *priv = netdev_priv(dev); 358 359 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 360 ctrl_mask & ~(IF_MCONT_MSGLST | 361 IF_MCONT_INTPND | IF_MCONT_NEWDAT)); 362 c_can_object_put(dev, iface, obj, IF_COMM_CONTROL); 363} 364 365static void c_can_handle_lost_msg_obj(struct net_device *dev, 366 int iface, int objno) 367{ 368 struct c_can_priv *priv = netdev_priv(dev); 369 struct net_device_stats *stats = &dev->stats; 370 struct sk_buff *skb; 371 struct can_frame *frame; 372 373 netdev_err(dev, "msg lost in buffer %d\n", objno); 374 375 c_can_object_get(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST); 376 377 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 378 IF_MCONT_CLR_MSGLST); 379 380 c_can_object_put(dev, 0, objno, IF_COMM_CONTROL); 381 382 /* create an error msg */ 383 skb = alloc_can_err_skb(dev, &frame); 384 if (unlikely(!skb)) 385 return; 386 387 frame->can_id |= CAN_ERR_CRTL; 388 frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW; 389 stats->rx_errors++; 390 stats->rx_over_errors++; 391 392 netif_receive_skb(skb); 393} 394 395static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl) 396{ 397 u16 flags, data; 398 int i; 399 unsigned int val; 400 struct c_can_priv *priv = netdev_priv(dev); 401 struct net_device_stats *stats = &dev->stats; 402 struct sk_buff *skb; 403 struct can_frame *frame; 404 405 skb = alloc_can_skb(dev, &frame); 406 if (!skb) { 407 stats->rx_dropped++; 408 return -ENOMEM; 409 } 410 411 frame->can_dlc = get_can_dlc(ctrl & 0x0F); 412 413 flags = priv->read_reg(priv, &priv->regs->ifregs[iface].arb2); 414 val = priv->read_reg(priv, &priv->regs->ifregs[iface].arb1) | 415 (flags << 16); 416 417 if (flags & IF_ARB_MSGXTD) 418 frame->can_id = (val & CAN_EFF_MASK) | CAN_EFF_FLAG; 419 else 420 frame->can_id = (val >> 18) & CAN_SFF_MASK; 421 422 if (flags & IF_ARB_TRANSMIT) 423 frame->can_id |= CAN_RTR_FLAG; 424 else { 425 for (i = 0; i < frame->can_dlc; i += 2) { 426 data = priv->read_reg(priv, 427 &priv->regs->ifregs[iface].data[i / 2]); 428 frame->data[i] = data; 429 frame->data[i + 1] = data >> 8; 430 } 431 } 432 433 netif_receive_skb(skb); 434 435 stats->rx_packets++; 436 stats->rx_bytes += frame->can_dlc; 437 438 return 0; 439} 440 441static void c_can_setup_receive_object(struct net_device *dev, int iface, 442 int objno, unsigned int mask, 443 unsigned int id, unsigned int mcont) 444{ 445 struct c_can_priv *priv = netdev_priv(dev); 446 447 priv->write_reg(priv, &priv->regs->ifregs[iface].mask1, 448 IFX_WRITE_LOW_16BIT(mask)); 449 priv->write_reg(priv, &priv->regs->ifregs[iface].mask2, 450 IFX_WRITE_HIGH_16BIT(mask)); 451 452 priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, 453 IFX_WRITE_LOW_16BIT(id)); 454 priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, 455 (IF_ARB_MSGVAL | IFX_WRITE_HIGH_16BIT(id))); 456 457 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, mcont); 458 c_can_object_put(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST); 459 460 netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, 461 c_can_read_reg32(priv, &priv->regs->msgval1)); 462} 463 464static void c_can_inval_msg_object(struct net_device *dev, int iface, int objno) 465{ 466 struct c_can_priv *priv = netdev_priv(dev); 467 468 priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, 0); 469 priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, 0); 470 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 0); 471 472 c_can_object_put(dev, iface, objno, IF_COMM_ARB | IF_COMM_CONTROL); 473 474 netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, 475 c_can_read_reg32(priv, &priv->regs->msgval1)); 476} 477 478static inline int c_can_is_next_tx_obj_busy(struct c_can_priv *priv, int objno) 479{ 480 int val = c_can_read_reg32(priv, &priv->regs->txrqst1); 481 482 /* 483 * as transmission request register's bit n-1 corresponds to 484 * message object n, we need to handle the same properly. 485 */ 486 if (val & (1 << (objno - 1))) 487 return 1; 488 489 return 0; 490} 491 492static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, 493 struct net_device *dev) 494{ 495 u32 msg_obj_no; 496 struct c_can_priv *priv = netdev_priv(dev); 497 struct can_frame *frame = (struct can_frame *)skb->data; 498 499 if (can_dropped_invalid_skb(dev, skb)) 500 return NETDEV_TX_OK; 501 502 msg_obj_no = get_tx_next_msg_obj(priv); 503 504 /* prepare message object for transmission */ 505 c_can_write_msg_object(dev, 0, frame, msg_obj_no); 506 can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); 507 508 /* 509 * we have to stop the queue in case of a wrap around or 510 * if the next TX message object is still in use 511 */ 512 priv->tx_next++; 513 if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) || 514 (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0) 515 netif_stop_queue(dev); 516 517 return NETDEV_TX_OK; 518} 519 520static int c_can_set_bittiming(struct net_device *dev) 521{ 522 unsigned int reg_btr, reg_brpe, ctrl_save; 523 u8 brp, brpe, sjw, tseg1, tseg2; 524 u32 ten_bit_brp; 525 struct c_can_priv *priv = netdev_priv(dev); 526 const struct can_bittiming *bt = &priv->can.bittiming; 527 528 /* c_can provides a 6-bit brp and 4-bit brpe fields */ 529 ten_bit_brp = bt->brp - 1; 530 brp = ten_bit_brp & BTR_BRP_MASK; 531 brpe = ten_bit_brp >> 6; 532 533 sjw = bt->sjw - 1; 534 tseg1 = bt->prop_seg + bt->phase_seg1 - 1; 535 tseg2 = bt->phase_seg2 - 1; 536 reg_btr = brp | (sjw << BTR_SJW_SHIFT) | (tseg1 << BTR_TSEG1_SHIFT) | 537 (tseg2 << BTR_TSEG2_SHIFT); 538 reg_brpe = brpe & BRP_EXT_BRPE_MASK; 539 540 netdev_info(dev, 541 "setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe); 542 543 ctrl_save = priv->read_reg(priv, &priv->regs->control); 544 priv->write_reg(priv, &priv->regs->control, 545 ctrl_save | CONTROL_CCE | CONTROL_INIT); 546 priv->write_reg(priv, &priv->regs->btr, reg_btr); 547 priv->write_reg(priv, &priv->regs->brp_ext, reg_brpe); 548 priv->write_reg(priv, &priv->regs->control, ctrl_save); 549 550 return 0; 551} 552 553/* 554 * Configure C_CAN message objects for Tx and Rx purposes: 555 * C_CAN provides a total of 32 message objects that can be configured 556 * either for Tx or Rx purposes. Here the first 16 message objects are used as 557 * a reception FIFO. The end of reception FIFO is signified by the EoB bit 558 * being SET. The remaining 16 message objects are kept aside for Tx purposes. 559 * See user guide document for further details on configuring message 560 * objects. 561 */ 562static void c_can_configure_msg_objects(struct net_device *dev) 563{ 564 int i; 565 566 /* first invalidate all message objects */ 567 for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++) 568 c_can_inval_msg_object(dev, 0, i); 569 570 /* setup receive message objects */ 571 for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++) 572 c_can_setup_receive_object(dev, 0, i, 0, 0, 573 (IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB); 574 575 c_can_setup_receive_object(dev, 0, C_CAN_MSG_OBJ_RX_LAST, 0, 0, 576 IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK); 577} 578 579/* 580 * Configure C_CAN chip: 581 * - enable/disable auto-retransmission 582 * - set operating mode 583 * - configure message objects 584 */ 585static void c_can_chip_config(struct net_device *dev) 586{ 587 struct c_can_priv *priv = netdev_priv(dev); 588 589 /* enable automatic retransmission */ 590 priv->write_reg(priv, &priv->regs->control, 591 CONTROL_ENABLE_AR); 592 593 if ((priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) && 594 (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)) { 595 /* loopback + silent mode : useful for hot self-test */ 596 priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | 597 CONTROL_SIE | CONTROL_IE | CONTROL_TEST); 598 priv->write_reg(priv, &priv->regs->test, 599 TEST_LBACK | TEST_SILENT); 600 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) { 601 /* loopback mode : useful for self-test function */ 602 priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | 603 CONTROL_SIE | CONTROL_IE | CONTROL_TEST); 604 priv->write_reg(priv, &priv->regs->test, TEST_LBACK); 605 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) { 606 /* silent mode : bus-monitoring mode */ 607 priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | 608 CONTROL_SIE | CONTROL_IE | CONTROL_TEST); 609 priv->write_reg(priv, &priv->regs->test, TEST_SILENT); 610 } else 611 /* normal mode*/ 612 priv->write_reg(priv, &priv->regs->control, 613 CONTROL_EIE | CONTROL_SIE | CONTROL_IE); 614 615 /* configure message objects */ 616 c_can_configure_msg_objects(dev); 617 618 /* set a `lec` value so that we can check for updates later */ 619 priv->write_reg(priv, &priv->regs->status, LEC_UNUSED); 620 621 /* set bittiming params */ 622 c_can_set_bittiming(dev); 623} 624 625static void c_can_start(struct net_device *dev) 626{ 627 struct c_can_priv *priv = netdev_priv(dev); 628 629 /* basic c_can configuration */ 630 c_can_chip_config(dev); 631 632 priv->can.state = CAN_STATE_ERROR_ACTIVE; 633 634 /* reset tx helper pointers */ 635 priv->tx_next = priv->tx_echo = 0; 636 637 /* enable status change, error and module interrupts */ 638 c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS); 639} 640 641static void c_can_stop(struct net_device *dev) 642{ 643 struct c_can_priv *priv = netdev_priv(dev); 644 645 /* disable all interrupts */ 646 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); 647 648 /* set the state as STOPPED */ 649 priv->can.state = CAN_STATE_STOPPED; 650} 651 652static int c_can_set_mode(struct net_device *dev, enum can_mode mode) 653{ 654 switch (mode) { 655 case CAN_MODE_START: 656 c_can_start(dev); 657 netif_wake_queue(dev); 658 break; 659 default: 660 return -EOPNOTSUPP; 661 } 662 663 return 0; 664} 665 666static int c_can_get_berr_counter(const struct net_device *dev, 667 struct can_berr_counter *bec) 668{ 669 unsigned int reg_err_counter; 670 struct c_can_priv *priv = netdev_priv(dev); 671 672 reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt); 673 bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >> 674 ERR_CNT_REC_SHIFT; 675 bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK; 676 677 return 0; 678} 679 680/* 681 * theory of operation: 682 * 683 * priv->tx_echo holds the number of the oldest can_frame put for 684 * transmission into the hardware, but not yet ACKed by the CAN tx 685 * complete IRQ. 686 * 687 * We iterate from priv->tx_echo to priv->tx_next and check if the 688 * packet has been transmitted, echo it back to the CAN framework. 689 * If we discover a not yet transmitted packet, stop looking for more. 690 */ 691static void c_can_do_tx(struct net_device *dev) 692{ 693 u32 val; 694 u32 msg_obj_no; 695 struct c_can_priv *priv = netdev_priv(dev); 696 struct net_device_stats *stats = &dev->stats; 697 698 for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) { 699 msg_obj_no = get_tx_echo_msg_obj(priv); 700 val = c_can_read_reg32(priv, &priv->regs->txrqst1); 701 if (!(val & (1 << (msg_obj_no - 1)))) { 702 can_get_echo_skb(dev, 703 msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); 704 stats->tx_bytes += priv->read_reg(priv, 705 &priv->regs->ifregs[0].msg_cntrl) 706 & IF_MCONT_DLC_MASK; 707 stats->tx_packets++; 708 c_can_inval_msg_object(dev, 0, msg_obj_no); 709 } else { 710 break; 711 } 712 } 713 714 /* restart queue if wrap-up or if queue stalled on last pkt */ 715 if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) || 716 ((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0)) 717 netif_wake_queue(dev); 718} 719 720/* 721 * theory of operation: 722 * 723 * c_can core saves a received CAN message into the first free message 724 * object it finds free (starting with the lowest). Bits NEWDAT and 725 * INTPND are set for this message object indicating that a new message 726 * has arrived. To work-around this issue, we keep two groups of message 727 * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT. 728 * 729 * To ensure in-order frame reception we use the following 730 * approach while re-activating a message object to receive further 731 * frames: 732 * - if the current message object number is lower than 733 * C_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing 734 * the INTPND bit. 735 * - if the current message object number is equal to 736 * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower 737 * receive message objects. 738 * - if the current message object number is greater than 739 * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of 740 * only this message object. 741 */ 742static int c_can_do_rx_poll(struct net_device *dev, int quota) 743{ 744 u32 num_rx_pkts = 0; 745 unsigned int msg_obj, msg_ctrl_save; 746 struct c_can_priv *priv = netdev_priv(dev); 747 u32 val = c_can_read_reg32(priv, &priv->regs->intpnd1); 748 749 for (msg_obj = C_CAN_MSG_OBJ_RX_FIRST; 750 msg_obj <= C_CAN_MSG_OBJ_RX_LAST && quota > 0; 751 val = c_can_read_reg32(priv, &priv->regs->intpnd1), 752 msg_obj++) { 753 /* 754 * as interrupt pending register's bit n-1 corresponds to 755 * message object n, we need to handle the same properly. 756 */ 757 if (val & (1 << (msg_obj - 1))) { 758 c_can_object_get(dev, 0, msg_obj, IF_COMM_ALL & 759 ~IF_COMM_TXRQST); 760 msg_ctrl_save = priv->read_reg(priv, 761 &priv->regs->ifregs[0].msg_cntrl); 762 763 if (msg_ctrl_save & IF_MCONT_EOB) 764 return num_rx_pkts; 765 766 if (msg_ctrl_save & IF_MCONT_MSGLST) { 767 c_can_handle_lost_msg_obj(dev, 0, msg_obj); 768 num_rx_pkts++; 769 quota--; 770 continue; 771 } 772 773 if (!(msg_ctrl_save & IF_MCONT_NEWDAT)) 774 continue; 775 776 /* read the data from the message object */ 777 c_can_read_msg_object(dev, 0, msg_ctrl_save); 778 779 if (msg_obj < C_CAN_MSG_RX_LOW_LAST) 780 c_can_mark_rx_msg_obj(dev, 0, 781 msg_ctrl_save, msg_obj); 782 else if (msg_obj > C_CAN_MSG_RX_LOW_LAST) 783 /* activate this msg obj */ 784 c_can_activate_rx_msg_obj(dev, 0, 785 msg_ctrl_save, msg_obj); 786 else if (msg_obj == C_CAN_MSG_RX_LOW_LAST) 787 /* activate all lower message objects */ 788 c_can_activate_all_lower_rx_msg_obj(dev, 789 0, msg_ctrl_save); 790 791 num_rx_pkts++; 792 quota--; 793 } 794 } 795 796 return num_rx_pkts; 797} 798 799static inline int c_can_has_and_handle_berr(struct c_can_priv *priv) 800{ 801 return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) && 802 (priv->current_status & LEC_UNUSED); 803} 804 805static int c_can_handle_state_change(struct net_device *dev, 806 enum c_can_bus_error_types error_type) 807{ 808 unsigned int reg_err_counter; 809 unsigned int rx_err_passive; 810 struct c_can_priv *priv = netdev_priv(dev); 811 struct net_device_stats *stats = &dev->stats; 812 struct can_frame *cf; 813 struct sk_buff *skb; 814 struct can_berr_counter bec; 815 816 /* propagate the error condition to the CAN stack */ 817 skb = alloc_can_err_skb(dev, &cf); 818 if (unlikely(!skb)) 819 return 0; 820 821 c_can_get_berr_counter(dev, &bec); 822 reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt); 823 rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >> 824 ERR_CNT_RP_SHIFT; 825 826 switch (error_type) { 827 case C_CAN_ERROR_WARNING: 828 /* error warning state */ 829 priv->can.can_stats.error_warning++; 830 priv->can.state = CAN_STATE_ERROR_WARNING; 831 cf->can_id |= CAN_ERR_CRTL; 832 cf->data[1] = (bec.txerr > bec.rxerr) ? 833 CAN_ERR_CRTL_TX_WARNING : 834 CAN_ERR_CRTL_RX_WARNING; 835 cf->data[6] = bec.txerr; 836 cf->data[7] = bec.rxerr; 837 838 break; 839 case C_CAN_ERROR_PASSIVE: 840 /* error passive state */ 841 priv->can.can_stats.error_passive++; 842 priv->can.state = CAN_STATE_ERROR_PASSIVE; 843 cf->can_id |= CAN_ERR_CRTL; 844 if (rx_err_passive) 845 cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE; 846 if (bec.txerr > 127) 847 cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE; 848 849 cf->data[6] = bec.txerr; 850 cf->data[7] = bec.rxerr; 851 break; 852 case C_CAN_BUS_OFF: 853 /* bus-off state */ 854 priv->can.state = CAN_STATE_BUS_OFF; 855 cf->can_id |= CAN_ERR_BUSOFF; 856 /* 857 * disable all interrupts in bus-off mode to ensure that 858 * the CPU is not hogged down 859 */ 860 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); 861 can_bus_off(dev); 862 break; 863 default: 864 break; 865 } 866 867 netif_receive_skb(skb); 868 stats->rx_packets++; 869 stats->rx_bytes += cf->can_dlc; 870 871 return 1; 872} 873 874static int c_can_handle_bus_err(struct net_device *dev, 875 enum c_can_lec_type lec_type) 876{ 877 struct c_can_priv *priv = netdev_priv(dev); 878 struct net_device_stats *stats = &dev->stats; 879 struct can_frame *cf; 880 struct sk_buff *skb; 881 882 /* 883 * early exit if no lec update or no error. 884 * no lec update means that no CAN bus event has been detected 885 * since CPU wrote 0x7 value to status reg. 886 */ 887 if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR) 888 return 0; 889 890 /* propagate the error condition to the CAN stack */ 891 skb = alloc_can_err_skb(dev, &cf); 892 if (unlikely(!skb)) 893 return 0; 894 895 /* 896 * check for 'last error code' which tells us the 897 * type of the last error to occur on the CAN bus 898 */ 899 900 /* common for all type of bus errors */ 901 priv->can.can_stats.bus_error++; 902 stats->rx_errors++; 903 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; 904 cf->data[2] |= CAN_ERR_PROT_UNSPEC; 905 906 switch (lec_type) { 907 case LEC_STUFF_ERROR: 908 netdev_dbg(dev, "stuff error\n"); 909 cf->data[2] |= CAN_ERR_PROT_STUFF; 910 break; 911 case LEC_FORM_ERROR: 912 netdev_dbg(dev, "form error\n"); 913 cf->data[2] |= CAN_ERR_PROT_FORM; 914 break; 915 case LEC_ACK_ERROR: 916 netdev_dbg(dev, "ack error\n"); 917 cf->data[2] |= (CAN_ERR_PROT_LOC_ACK | 918 CAN_ERR_PROT_LOC_ACK_DEL); 919 break; 920 case LEC_BIT1_ERROR: 921 netdev_dbg(dev, "bit1 error\n"); 922 cf->data[2] |= CAN_ERR_PROT_BIT1; 923 break; 924 case LEC_BIT0_ERROR: 925 netdev_dbg(dev, "bit0 error\n"); 926 cf->data[2] |= CAN_ERR_PROT_BIT0; 927 break; 928 case LEC_CRC_ERROR: 929 netdev_dbg(dev, "CRC error\n"); 930 cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ | 931 CAN_ERR_PROT_LOC_CRC_DEL); 932 break; 933 default: 934 break; 935 } 936 937 /* set a `lec` value so that we can check for updates later */ 938 priv->write_reg(priv, &priv->regs->status, LEC_UNUSED); 939 940 netif_receive_skb(skb); 941 stats->rx_packets++; 942 stats->rx_bytes += cf->can_dlc; 943 944 return 1; 945} 946 947static int c_can_poll(struct napi_struct *napi, int quota) 948{ 949 u16 irqstatus; 950 int lec_type = 0; 951 int work_done = 0; 952 struct net_device *dev = napi->dev; 953 struct c_can_priv *priv = netdev_priv(dev); 954 955 irqstatus = priv->irqstatus; 956 if (!irqstatus) 957 goto end; 958 959 /* status events have the highest priority */ 960 if (irqstatus == STATUS_INTERRUPT) { 961 priv->current_status = priv->read_reg(priv, 962 &priv->regs->status); 963 964 /* handle Tx/Rx events */ 965 if (priv->current_status & STATUS_TXOK) 966 priv->write_reg(priv, &priv->regs->status, 967 priv->current_status & ~STATUS_TXOK); 968 969 if (priv->current_status & STATUS_RXOK) 970 priv->write_reg(priv, &priv->regs->status, 971 priv->current_status & ~STATUS_RXOK); 972 973 /* handle state changes */ 974 if ((priv->current_status & STATUS_EWARN) && 975 (!(priv->last_status & STATUS_EWARN))) { 976 netdev_dbg(dev, "entered error warning state\n"); 977 work_done += c_can_handle_state_change(dev, 978 C_CAN_ERROR_WARNING); 979 } 980 if ((priv->current_status & STATUS_EPASS) && 981 (!(priv->last_status & STATUS_EPASS))) { 982 netdev_dbg(dev, "entered error passive state\n"); 983 work_done += c_can_handle_state_change(dev, 984 C_CAN_ERROR_PASSIVE); 985 } 986 if ((priv->current_status & STATUS_BOFF) && 987 (!(priv->last_status & STATUS_BOFF))) { 988 netdev_dbg(dev, "entered bus off state\n"); 989 work_done += c_can_handle_state_change(dev, 990 C_CAN_BUS_OFF); 991 } 992 993 /* handle bus recovery events */ 994 if ((!(priv->current_status & STATUS_BOFF)) && 995 (priv->last_status & STATUS_BOFF)) { 996 netdev_dbg(dev, "left bus off state\n"); 997 priv->can.state = CAN_STATE_ERROR_ACTIVE; 998 } 999 if ((!(priv->current_status & STATUS_EPASS)) && 1000 (priv->last_status & STATUS_EPASS)) { 1001 netdev_dbg(dev, "left error passive state\n"); 1002 priv->can.state = CAN_STATE_ERROR_ACTIVE; 1003 } 1004 1005 priv->last_status = priv->current_status; 1006 1007 /* handle lec errors on the bus */ 1008 lec_type = c_can_has_and_handle_berr(priv); 1009 if (lec_type) 1010 work_done += c_can_handle_bus_err(dev, lec_type); 1011 } else if ((irqstatus >= C_CAN_MSG_OBJ_RX_FIRST) && 1012 (irqstatus <= C_CAN_MSG_OBJ_RX_LAST)) { 1013 /* handle events corresponding to receive message objects */ 1014 work_done += c_can_do_rx_poll(dev, (quota - work_done)); 1015 } else if ((irqstatus >= C_CAN_MSG_OBJ_TX_FIRST) && 1016 (irqstatus <= C_CAN_MSG_OBJ_TX_LAST)) { 1017 /* handle events corresponding to transmit message objects */ 1018 c_can_do_tx(dev); 1019 } 1020 1021end: 1022 if (work_done < quota) { 1023 napi_complete(napi); 1024 /* enable all IRQs */ 1025 c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS); 1026 } 1027 1028 return work_done; 1029} 1030 1031static irqreturn_t c_can_isr(int irq, void *dev_id) 1032{ 1033 struct net_device *dev = (struct net_device *)dev_id; 1034 struct c_can_priv *priv = netdev_priv(dev); 1035 1036 priv->irqstatus = priv->read_reg(priv, &priv->regs->interrupt); 1037 if (!priv->irqstatus) 1038 return IRQ_NONE; 1039 1040 /* disable all interrupts and schedule the NAPI */ 1041 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); 1042 napi_schedule(&priv->napi); 1043 1044 return IRQ_HANDLED; 1045} 1046 1047static int c_can_open(struct net_device *dev) 1048{ 1049 int err; 1050 struct c_can_priv *priv = netdev_priv(dev); 1051 1052 /* open the can device */ 1053 err = open_candev(dev); 1054 if (err) { 1055 netdev_err(dev, "failed to open can device\n"); 1056 return err; 1057 } 1058 1059 /* register interrupt handler */ 1060 err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name, 1061 dev); 1062 if (err < 0) { 1063 netdev_err(dev, "failed to request interrupt\n"); 1064 goto exit_irq_fail; 1065 } 1066 1067 napi_enable(&priv->napi); 1068 1069 /* start the c_can controller */ 1070 c_can_start(dev); 1071 1072 netif_start_queue(dev); 1073 1074 return 0; 1075 1076exit_irq_fail: 1077 close_candev(dev); 1078 return err; 1079} 1080 1081static int c_can_close(struct net_device *dev) 1082{ 1083 struct c_can_priv *priv = netdev_priv(dev); 1084 1085 netif_stop_queue(dev); 1086 napi_disable(&priv->napi); 1087 c_can_stop(dev); 1088 free_irq(dev->irq, dev); 1089 close_candev(dev); 1090 1091 return 0; 1092} 1093 1094struct net_device *alloc_c_can_dev(void) 1095{ 1096 struct net_device *dev; 1097 struct c_can_priv *priv; 1098 1099 dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM); 1100 if (!dev) 1101 return NULL; 1102 1103 priv = netdev_priv(dev); 1104 netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT); 1105 1106 priv->dev = dev; 1107 priv->can.bittiming_const = &c_can_bittiming_const; 1108 priv->can.do_set_mode = c_can_set_mode; 1109 priv->can.do_get_berr_counter = c_can_get_berr_counter; 1110 priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK | 1111 CAN_CTRLMODE_LISTENONLY | 1112 CAN_CTRLMODE_BERR_REPORTING; 1113 1114 return dev; 1115} 1116EXPORT_SYMBOL_GPL(alloc_c_can_dev); 1117 1118void free_c_can_dev(struct net_device *dev) 1119{ 1120 free_candev(dev); 1121} 1122EXPORT_SYMBOL_GPL(free_c_can_dev); 1123 1124static const struct net_device_ops c_can_netdev_ops = { 1125 .ndo_open = c_can_open, 1126 .ndo_stop = c_can_close, 1127 .ndo_start_xmit = c_can_start_xmit, 1128}; 1129 1130int register_c_can_dev(struct net_device *dev) 1131{ 1132 dev->flags |= IFF_ECHO; /* we support local echo */ 1133 dev->netdev_ops = &c_can_netdev_ops; 1134 1135 return register_candev(dev); 1136} 1137EXPORT_SYMBOL_GPL(register_c_can_dev); 1138 1139void unregister_c_can_dev(struct net_device *dev) 1140{ 1141 struct c_can_priv *priv = netdev_priv(dev); 1142 1143 /* disable all interrupts */ 1144 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); 1145 1146 unregister_candev(dev); 1147} 1148EXPORT_SYMBOL_GPL(unregister_c_can_dev); 1149 1150MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>"); 1151MODULE_LICENSE("GPL v2"); 1152MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller"); 1153