700 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * CAN bus driver for the alone generic (as possible as) MSCAN controller.4 *5 * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,6 * Varma Electronics Oy7 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>8 * Copyright (C) 2008-2009 Pengutronix <kernel@pengutronix.de>9 */10 11#include <linux/kernel.h>12#include <linux/module.h>13#include <linux/interrupt.h>14#include <linux/delay.h>15#include <linux/netdevice.h>16#include <linux/if_arp.h>17#include <linux/if_ether.h>18#include <linux/list.h>19#include <linux/can/dev.h>20#include <linux/can/error.h>21#include <linux/io.h>22 23#include "mscan.h"24 25static const struct can_bittiming_const mscan_bittiming_const = {26 .name = "mscan",27 .tseg1_min = 4,28 .tseg1_max = 16,29 .tseg2_min = 2,30 .tseg2_max = 8,31 .sjw_max = 4,32 .brp_min = 1,33 .brp_max = 64,34 .brp_inc = 1,35};36 37static enum can_state state_map[] = {38 CAN_STATE_ERROR_ACTIVE,39 CAN_STATE_ERROR_WARNING,40 CAN_STATE_ERROR_PASSIVE,41 CAN_STATE_BUS_OFF42};43 44static int mscan_set_mode(struct net_device *dev, u8 mode)45{46 struct mscan_priv *priv = netdev_priv(dev);47 struct mscan_regs __iomem *regs = priv->reg_base;48 int ret = 0;49 int i;50 u8 canctl1;51 52 if (mode != MSCAN_NORMAL_MODE) {53 if (priv->tx_active) {54 /* Abort transfers before going to sleep */#55 out_8(®s->cantarq, priv->tx_active);56 /* Suppress TX done interrupts */57 out_8(®s->cantier, 0);58 }59 60 canctl1 = in_8(®s->canctl1);61 if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) {62 setbits8(®s->canctl0, MSCAN_SLPRQ);63 for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {64 if (in_8(®s->canctl1) & MSCAN_SLPAK)65 break;66 udelay(100);67 }68 /*69 * The mscan controller will fail to enter sleep mode,70 * while there are irregular activities on bus, like71 * somebody keeps retransmitting. This behavior is72 * undocumented and seems to differ between mscan built73 * in mpc5200b and mpc5200. We proceed in that case,74 * since otherwise the slprq will be kept set and the75 * controller will get stuck. NOTE: INITRQ or CSWAI76 * will abort all active transmit actions, if still77 * any, at once.78 */79 if (i >= MSCAN_SET_MODE_RETRIES)80 netdev_dbg(dev,81 "device failed to enter sleep mode. "82 "We proceed anyhow.\n");83 else84 priv->can.state = CAN_STATE_SLEEPING;85 }86 87 if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {88 setbits8(®s->canctl0, MSCAN_INITRQ);89 for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {90 if (in_8(®s->canctl1) & MSCAN_INITAK)91 break;92 }93 if (i >= MSCAN_SET_MODE_RETRIES)94 ret = -ENODEV;95 }96 if (!ret)97 priv->can.state = CAN_STATE_STOPPED;98 99 if (mode & MSCAN_CSWAI)100 setbits8(®s->canctl0, MSCAN_CSWAI);101 102 } else {103 canctl1 = in_8(®s->canctl1);104 if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {105 clrbits8(®s->canctl0, MSCAN_SLPRQ | MSCAN_INITRQ);106 for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {107 canctl1 = in_8(®s->canctl1);108 if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))109 break;110 }111 if (i >= MSCAN_SET_MODE_RETRIES)112 ret = -ENODEV;113 else114 priv->can.state = CAN_STATE_ERROR_ACTIVE;115 }116 }117 return ret;118}119 120static int mscan_start(struct net_device *dev)121{122 struct mscan_priv *priv = netdev_priv(dev);123 struct mscan_regs __iomem *regs = priv->reg_base;124 u8 canrflg;125 int err;126 127 out_8(®s->canrier, 0);128 129 INIT_LIST_HEAD(&priv->tx_head);130 priv->prev_buf_id = 0;131 priv->cur_pri = 0;132 priv->tx_active = 0;133 priv->shadow_canrier = 0;134 priv->flags = 0;135 136 if (priv->type == MSCAN_TYPE_MPC5121) {137 /* Clear pending bus-off condition */138 if (in_8(®s->canmisc) & MSCAN_BOHOLD)139 out_8(®s->canmisc, MSCAN_BOHOLD);140 }141 142 err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);143 if (err)144 return err;145 146 canrflg = in_8(®s->canrflg);147 priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;148 priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),149 MSCAN_STATE_TX(canrflg))];150 out_8(®s->cantier, 0);151 152 /* Enable receive interrupts. */153 out_8(®s->canrier, MSCAN_RX_INTS_ENABLE);154 155 return 0;156}157 158static int mscan_restart(struct net_device *dev)159{160 struct mscan_priv *priv = netdev_priv(dev);161 162 if (priv->type == MSCAN_TYPE_MPC5121) {163 struct mscan_regs __iomem *regs = priv->reg_base;164 165 priv->can.state = CAN_STATE_ERROR_ACTIVE;166 WARN(!(in_8(®s->canmisc) & MSCAN_BOHOLD),167 "bus-off state expected\n");168 out_8(®s->canmisc, MSCAN_BOHOLD);169 /* Re-enable receive interrupts. */170 out_8(®s->canrier, MSCAN_RX_INTS_ENABLE);171 } else {172 if (priv->can.state <= CAN_STATE_BUS_OFF)173 mscan_set_mode(dev, MSCAN_INIT_MODE);174 return mscan_start(dev);175 }176 177 return 0;178}179 180static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)181{182 struct can_frame *frame = (struct can_frame *)skb->data;183 struct mscan_priv *priv = netdev_priv(dev);184 struct mscan_regs __iomem *regs = priv->reg_base;185 int i, rtr, buf_id;186 u32 can_id;187 188 if (can_dev_dropped_skb(dev, skb))189 return NETDEV_TX_OK;190 191 out_8(®s->cantier, 0);192 193 i = ~priv->tx_active & MSCAN_TXE;194 buf_id = ffs(i) - 1;195 switch (hweight8(i)) {196 case 0:197 netif_stop_queue(dev);198 netdev_err(dev, "Tx Ring full when queue awake!\n");199 return NETDEV_TX_BUSY;200 case 1:201 /*202 * if buf_id < 3, then current frame will be send out of order,203 * since buffer with lower id have higher priority (hell..)204 */205 netif_stop_queue(dev);206 fallthrough;207 case 2:208 if (buf_id < priv->prev_buf_id) {209 priv->cur_pri++;210 if (priv->cur_pri == 0xff) {211 set_bit(F_TX_WAIT_ALL, &priv->flags);212 netif_stop_queue(dev);213 }214 }215 set_bit(F_TX_PROGRESS, &priv->flags);216 break;217 }218 priv->prev_buf_id = buf_id;219 out_8(®s->cantbsel, i);220 221 rtr = frame->can_id & CAN_RTR_FLAG;222 223 /* RTR is always the lowest bit of interest, then IDs follow */224 if (frame->can_id & CAN_EFF_FLAG) {225 can_id = (frame->can_id & CAN_EFF_MASK)226 << (MSCAN_EFF_RTR_SHIFT + 1);227 if (rtr)228 can_id |= 1 << MSCAN_EFF_RTR_SHIFT;229 out_be16(®s->tx.idr3_2, can_id);230 231 can_id >>= 16;232 /* EFF_FLAGS are between the IDs :( */233 can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0)234 | MSCAN_EFF_FLAGS;235 } else {236 can_id = (frame->can_id & CAN_SFF_MASK)237 << (MSCAN_SFF_RTR_SHIFT + 1);238 if (rtr)239 can_id |= 1 << MSCAN_SFF_RTR_SHIFT;240 }241 out_be16(®s->tx.idr1_0, can_id);242 243 if (!rtr) {244 void __iomem *data = ®s->tx.dsr1_0;245 u16 *payload = (u16 *)frame->data;246 247 for (i = 0; i < frame->len / 2; i++) {248 out_be16(data, *payload++);249 data += 2 + _MSCAN_RESERVED_DSR_SIZE;250 }251 /* write remaining byte if necessary */252 if (frame->len & 1)253 out_8(data, frame->data[frame->len - 1]);254 }255 256 out_8(®s->tx.dlr, frame->len);257 out_8(®s->tx.tbpr, priv->cur_pri);258 259 /* Start transmission. */260 out_8(®s->cantflg, 1 << buf_id);261 262 if (!test_bit(F_TX_PROGRESS, &priv->flags))263 netif_trans_update(dev);264 265 list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);266 267 can_put_echo_skb(skb, dev, buf_id, 0);268 269 /* Enable interrupt. */270 priv->tx_active |= 1 << buf_id;271 out_8(®s->cantier, priv->tx_active);272 273 return NETDEV_TX_OK;274}275 276static enum can_state get_new_state(struct net_device *dev, u8 canrflg)277{278 struct mscan_priv *priv = netdev_priv(dev);279 280 if (unlikely(canrflg & MSCAN_CSCIF))281 return state_map[max(MSCAN_STATE_RX(canrflg),282 MSCAN_STATE_TX(canrflg))];283 284 return priv->can.state;285}286 287static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)288{289 struct mscan_priv *priv = netdev_priv(dev);290 struct mscan_regs __iomem *regs = priv->reg_base;291 u32 can_id;292 int i;293 294 can_id = in_be16(®s->rx.idr1_0);295 if (can_id & (1 << 3)) {296 frame->can_id = CAN_EFF_FLAG;297 can_id = ((can_id << 16) | in_be16(®s->rx.idr3_2));298 can_id = ((can_id & 0xffe00000) |299 ((can_id & 0x7ffff) << 2)) >> 2;300 } else {301 can_id >>= 4;302 frame->can_id = 0;303 }304 305 frame->can_id |= can_id >> 1;306 if (can_id & 1)307 frame->can_id |= CAN_RTR_FLAG;308 309 frame->len = can_cc_dlc2len(in_8(®s->rx.dlr) & 0xf);310 311 if (!(frame->can_id & CAN_RTR_FLAG)) {312 void __iomem *data = ®s->rx.dsr1_0;313 u16 *payload = (u16 *)frame->data;314 315 for (i = 0; i < frame->len / 2; i++) {316 *payload++ = in_be16(data);317 data += 2 + _MSCAN_RESERVED_DSR_SIZE;318 }319 /* read remaining byte if necessary */320 if (frame->len & 1)321 frame->data[frame->len - 1] = in_8(data);322 }323 324 out_8(®s->canrflg, MSCAN_RXF);325}326 327static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,328 u8 canrflg)329{330 struct mscan_priv *priv = netdev_priv(dev);331 struct mscan_regs __iomem *regs = priv->reg_base;332 struct net_device_stats *stats = &dev->stats;333 enum can_state new_state;334 335 netdev_dbg(dev, "error interrupt (canrflg=%#x)\n", canrflg);336 frame->can_id = CAN_ERR_FLAG;337 338 if (canrflg & MSCAN_OVRIF) {339 frame->can_id |= CAN_ERR_CRTL;340 frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;341 stats->rx_over_errors++;342 stats->rx_errors++;343 } else {344 frame->data[1] = 0;345 }346 347 new_state = get_new_state(dev, canrflg);348 if (new_state != priv->can.state) {349 can_change_state(dev, frame,350 state_map[MSCAN_STATE_TX(canrflg)],351 state_map[MSCAN_STATE_RX(canrflg)]);352 353 if (priv->can.state == CAN_STATE_BUS_OFF) {354 /*355 * The MSCAN on the MPC5200 does recover from bus-off356 * automatically. To avoid that we stop the chip doing357 * a light-weight stop (we are in irq-context).358 */359 if (priv->type != MSCAN_TYPE_MPC5121) {360 out_8(®s->cantier, 0);361 out_8(®s->canrier, 0);362 setbits8(®s->canctl0,363 MSCAN_SLPRQ | MSCAN_INITRQ);364 }365 can_bus_off(dev);366 }367 }368 priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;369 frame->len = CAN_ERR_DLC;370 out_8(®s->canrflg, MSCAN_ERR_IF);371}372 373static int mscan_rx_poll(struct napi_struct *napi, int quota)374{375 struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);376 struct net_device *dev = napi->dev;377 struct mscan_regs __iomem *regs = priv->reg_base;378 struct net_device_stats *stats = &dev->stats;379 int work_done = 0;380 struct sk_buff *skb;381 struct can_frame *frame;382 u8 canrflg;383 384 while (work_done < quota) {385 canrflg = in_8(®s->canrflg);386 if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))387 break;388 389 skb = alloc_can_skb(dev, &frame);390 if (!skb) {391 if (printk_ratelimit())392 netdev_notice(dev, "packet dropped\n");393 stats->rx_dropped++;394 out_8(®s->canrflg, canrflg);395 continue;396 }397 398 if (canrflg & MSCAN_RXF) {399 mscan_get_rx_frame(dev, frame);400 stats->rx_packets++;401 if (!(frame->can_id & CAN_RTR_FLAG))402 stats->rx_bytes += frame->len;403 } else if (canrflg & MSCAN_ERR_IF) {404 mscan_get_err_frame(dev, frame, canrflg);405 }406 407 work_done++;408 netif_receive_skb(skb);409 }410 411 if (work_done < quota) {412 if (likely(napi_complete_done(&priv->napi, work_done))) {413 clear_bit(F_RX_PROGRESS, &priv->flags);414 if (priv->can.state < CAN_STATE_BUS_OFF)415 out_8(®s->canrier, priv->shadow_canrier);416 }417 }418 return work_done;419}420 421static irqreturn_t mscan_isr(int irq, void *dev_id)422{423 struct net_device *dev = (struct net_device *)dev_id;424 struct mscan_priv *priv = netdev_priv(dev);425 struct mscan_regs __iomem *regs = priv->reg_base;426 struct net_device_stats *stats = &dev->stats;427 u8 cantier, cantflg, canrflg;428 irqreturn_t ret = IRQ_NONE;429 430 cantier = in_8(®s->cantier) & MSCAN_TXE;431 cantflg = in_8(®s->cantflg) & cantier;432 433 if (cantier && cantflg) {434 struct list_head *tmp, *pos;435 436 list_for_each_safe(pos, tmp, &priv->tx_head) {437 struct tx_queue_entry *entry =438 list_entry(pos, struct tx_queue_entry, list);439 u8 mask = entry->mask;440 441 if (!(cantflg & mask))442 continue;443 444 out_8(®s->cantbsel, mask);445 stats->tx_bytes += can_get_echo_skb(dev, entry->id,446 NULL);447 stats->tx_packets++;448 priv->tx_active &= ~mask;449 list_del(pos);450 }451 452 if (list_empty(&priv->tx_head)) {453 clear_bit(F_TX_WAIT_ALL, &priv->flags);454 clear_bit(F_TX_PROGRESS, &priv->flags);455 priv->cur_pri = 0;456 } else {457 netif_trans_update(dev);458 }459 460 if (!test_bit(F_TX_WAIT_ALL, &priv->flags))461 netif_wake_queue(dev);462 463 out_8(®s->cantier, priv->tx_active);464 ret = IRQ_HANDLED;465 }466 467 canrflg = in_8(®s->canrflg);468 if ((canrflg & ~MSCAN_STAT_MSK) &&469 !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {470 if (canrflg & ~MSCAN_STAT_MSK) {471 priv->shadow_canrier = in_8(®s->canrier);472 out_8(®s->canrier, 0);473 napi_schedule(&priv->napi);474 ret = IRQ_HANDLED;475 } else {476 clear_bit(F_RX_PROGRESS, &priv->flags);477 }478 }479 return ret;480}481 482static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)483{484 int ret = 0;485 486 switch (mode) {487 case CAN_MODE_START:488 ret = mscan_restart(dev);489 if (ret)490 break;491 if (netif_queue_stopped(dev))492 netif_wake_queue(dev);493 break;494 495 default:496 ret = -EOPNOTSUPP;497 break;498 }499 return ret;500}501 502static int mscan_do_set_bittiming(struct net_device *dev)503{504 struct mscan_priv *priv = netdev_priv(dev);505 struct mscan_regs __iomem *regs = priv->reg_base;506 struct can_bittiming *bt = &priv->can.bittiming;507 u8 btr0, btr1;508 509 btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);510 btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |511 BTR1_SET_TSEG2(bt->phase_seg2) |512 BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));513 514 netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);515 516 out_8(®s->canbtr0, btr0);517 out_8(®s->canbtr1, btr1);518 519 return 0;520}521 522static int mscan_get_berr_counter(const struct net_device *dev,523 struct can_berr_counter *bec)524{525 struct mscan_priv *priv = netdev_priv(dev);526 struct mscan_regs __iomem *regs = priv->reg_base;527 528 bec->txerr = in_8(®s->cantxerr);529 bec->rxerr = in_8(®s->canrxerr);530 531 return 0;532}533 534static int mscan_open(struct net_device *dev)535{536 int ret;537 struct mscan_priv *priv = netdev_priv(dev);538 struct mscan_regs __iomem *regs = priv->reg_base;539 540 ret = clk_prepare_enable(priv->clk_ipg);541 if (ret)542 goto exit_retcode;543 ret = clk_prepare_enable(priv->clk_can);544 if (ret)545 goto exit_dis_ipg_clock;546 547 /* common open */548 ret = open_candev(dev);549 if (ret)550 goto exit_dis_can_clock;551 552 napi_enable(&priv->napi);553 554 ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);555 if (ret < 0) {556 netdev_err(dev, "failed to attach interrupt\n");557 goto exit_napi_disable;558 }559 560 if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)561 setbits8(®s->canctl1, MSCAN_LISTEN);562 else563 clrbits8(®s->canctl1, MSCAN_LISTEN);564 565 ret = mscan_start(dev);566 if (ret)567 goto exit_free_irq;568 569 netif_start_queue(dev);570 571 return 0;572 573exit_free_irq:574 free_irq(dev->irq, dev);575exit_napi_disable:576 napi_disable(&priv->napi);577 close_candev(dev);578exit_dis_can_clock:579 clk_disable_unprepare(priv->clk_can);580exit_dis_ipg_clock:581 clk_disable_unprepare(priv->clk_ipg);582exit_retcode:583 return ret;584}585 586static int mscan_close(struct net_device *dev)587{588 struct mscan_priv *priv = netdev_priv(dev);589 struct mscan_regs __iomem *regs = priv->reg_base;590 591 netif_stop_queue(dev);592 napi_disable(&priv->napi);593 594 out_8(®s->cantier, 0);595 out_8(®s->canrier, 0);596 mscan_set_mode(dev, MSCAN_INIT_MODE);597 close_candev(dev);598 free_irq(dev->irq, dev);599 600 clk_disable_unprepare(priv->clk_can);601 clk_disable_unprepare(priv->clk_ipg);602 603 return 0;604}605 606static const struct net_device_ops mscan_netdev_ops = {607 .ndo_open = mscan_open,608 .ndo_stop = mscan_close,609 .ndo_start_xmit = mscan_start_xmit,610 .ndo_change_mtu = can_change_mtu,611};612 613static const struct ethtool_ops mscan_ethtool_ops = {614 .get_ts_info = ethtool_op_get_ts_info,615};616 617int register_mscandev(struct net_device *dev, int mscan_clksrc)618{619 struct mscan_priv *priv = netdev_priv(dev);620 struct mscan_regs __iomem *regs = priv->reg_base;621 u8 ctl1;622 623 ctl1 = in_8(®s->canctl1);624 if (mscan_clksrc)625 ctl1 |= MSCAN_CLKSRC;626 else627 ctl1 &= ~MSCAN_CLKSRC;628 629 if (priv->type == MSCAN_TYPE_MPC5121) {630 priv->can.do_get_berr_counter = mscan_get_berr_counter;631 ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */632 }633 634 ctl1 |= MSCAN_CANE;635 out_8(®s->canctl1, ctl1);636 udelay(100);637 638 /* acceptance mask/acceptance code (accept everything) */639 out_be16(®s->canidar1_0, 0);640 out_be16(®s->canidar3_2, 0);641 out_be16(®s->canidar5_4, 0);642 out_be16(®s->canidar7_6, 0);643 644 out_be16(®s->canidmr1_0, 0xffff);645 out_be16(®s->canidmr3_2, 0xffff);646 out_be16(®s->canidmr5_4, 0xffff);647 out_be16(®s->canidmr7_6, 0xffff);648 /* Two 32 bit Acceptance Filters */649 out_8(®s->canidac, MSCAN_AF_32BIT);650 651 mscan_set_mode(dev, MSCAN_INIT_MODE);652 653 return register_candev(dev);654}655 656void unregister_mscandev(struct net_device *dev)657{658 struct mscan_priv *priv = netdev_priv(dev);659 struct mscan_regs __iomem *regs = priv->reg_base;660 mscan_set_mode(dev, MSCAN_INIT_MODE);661 clrbits8(®s->canctl1, MSCAN_CANE);662 unregister_candev(dev);663}664 665struct net_device *alloc_mscandev(void)666{667 struct net_device *dev;668 struct mscan_priv *priv;669 int i;670 671 dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);672 if (!dev)673 return NULL;674 priv = netdev_priv(dev);675 676 dev->netdev_ops = &mscan_netdev_ops;677 dev->ethtool_ops = &mscan_ethtool_ops;678 679 dev->flags |= IFF_ECHO; /* we support local echo */680 681 netif_napi_add_weight(dev, &priv->napi, mscan_rx_poll, 8);682 683 priv->can.bittiming_const = &mscan_bittiming_const;684 priv->can.do_set_bittiming = mscan_do_set_bittiming;685 priv->can.do_set_mode = mscan_do_set_mode;686 priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |687 CAN_CTRLMODE_LISTENONLY;688 689 for (i = 0; i < TX_QUEUE_SIZE; i++) {690 priv->tx_queue[i].id = i;691 priv->tx_queue[i].mask = 1 << i;692 }693 694 return dev;695}696 697MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");698MODULE_LICENSE("GPL v2");699MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");700