2 * CAN bus driver for the alone generic (as possible as) MSCAN controller.
4 * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,
6 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
7 * Copyright (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the version 2 of the GNU General Public License
11 * as published by the Free Software Foundation
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/interrupt.h>
26 #include <linux/delay.h>
27 #include <linux/netdevice.h>
28 #include <linux/if_arp.h>
29 #include <linux/if_ether.h>
30 #include <linux/list.h>
31 #include <linux/can.h>
32 #include <linux/can/dev.h>
33 #include <linux/can/error.h>
38 static struct can_bittiming_const mscan_bittiming_const = {
56 static enum can_state state_map[] = {
57 CAN_STATE_ERROR_ACTIVE,
58 CAN_STATE_ERROR_WARNING,
59 CAN_STATE_ERROR_PASSIVE,
63 static int mscan_set_mode(struct net_device *dev, u8 mode)
65 struct mscan_priv *priv = netdev_priv(dev);
66 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
71 if (mode != MSCAN_NORMAL_MODE) {
72 if (priv->tx_active) {
73 /* Abort transfers before going to sleep */#
74 out_8(®s->cantarq, priv->tx_active);
75 /* Suppress TX done interrupts */
76 out_8(®s->cantier, 0);
79 canctl1 = in_8(®s->canctl1);
80 if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) {
81 setbits8(®s->canctl0, MSCAN_SLPRQ);
82 for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
83 if (in_8(®s->canctl1) & MSCAN_SLPAK)
88 * The mscan controller will fail to enter sleep mode,
89 * while there are irregular activities on bus, like
90 * somebody keeps retransmitting. This behavior is
91 * undocumented and seems to differ between mscan built
92 * in mpc5200b and mpc5200. We proceed in that case,
93 * since otherwise the slprq will be kept set and the
94 * controller will get stuck. NOTE: INITRQ or CSWAI
95 * will abort all active transmit actions, if still
98 if (i >= MSCAN_SET_MODE_RETRIES)
99 dev_dbg(dev->dev.parent,
100 "device failed to enter sleep mode. "
101 "We proceed anyhow.\n");
103 priv->can.state = CAN_STATE_SLEEPING;
106 if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {
107 setbits8(®s->canctl0, MSCAN_INITRQ);
108 for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
109 if (in_8(®s->canctl1) & MSCAN_INITAK)
112 if (i >= MSCAN_SET_MODE_RETRIES)
116 priv->can.state = CAN_STATE_STOPPED;
118 if (mode & MSCAN_CSWAI)
119 setbits8(®s->canctl0, MSCAN_CSWAI);
122 canctl1 = in_8(®s->canctl1);
123 if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
124 clrbits8(®s->canctl0, MSCAN_SLPRQ | MSCAN_INITRQ);
125 for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
126 canctl1 = in_8(®s->canctl1);
127 if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
130 if (i >= MSCAN_SET_MODE_RETRIES)
133 priv->can.state = CAN_STATE_ERROR_ACTIVE;
139 static int mscan_start(struct net_device *dev)
141 struct mscan_priv *priv = netdev_priv(dev);
142 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
146 out_8(®s->canrier, 0);
148 INIT_LIST_HEAD(&priv->tx_head);
149 priv->prev_buf_id = 0;
152 priv->shadow_canrier = 0;
155 if (priv->type == MSCAN_TYPE_MPC5121) {
156 /* Clear pending bus-off condition */
157 if (in_8(®s->canmisc) & MSCAN_BOHOLD)
158 out_8(®s->canmisc, MSCAN_BOHOLD);
161 err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
165 canrflg = in_8(®s->canrflg);
166 priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
167 priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),
168 MSCAN_STATE_TX(canrflg))];
169 out_8(®s->cantier, 0);
171 /* Enable receive interrupts. */
172 out_8(®s->canrier, MSCAN_RX_INTS_ENABLE);
177 static int mscan_restart(struct net_device *dev)
179 struct mscan_priv *priv = netdev_priv(dev);
181 if (priv->type == MSCAN_TYPE_MPC5121) {
182 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
184 priv->can.state = CAN_STATE_ERROR_ACTIVE;
185 WARN(!(in_8(®s->canmisc) & MSCAN_BOHOLD),
186 "bus-off state expected");
187 out_8(®s->canmisc, MSCAN_BOHOLD);
188 /* Re-enable receive interrupts. */
189 out_8(®s->canrier, MSCAN_RX_INTS_ENABLE);
191 if (priv->can.state <= CAN_STATE_BUS_OFF)
192 mscan_set_mode(dev, MSCAN_INIT_MODE);
193 return mscan_start(dev);
199 static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
201 struct can_frame *frame = (struct can_frame *)skb->data;
202 struct mscan_priv *priv = netdev_priv(dev);
203 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
207 if (skb->len != sizeof(*frame) || frame->can_dlc > 8) {
209 dev->stats.tx_dropped++;
213 out_8(®s->cantier, 0);
215 i = ~priv->tx_active & MSCAN_TXE;
217 switch (hweight8(i)) {
219 netif_stop_queue(dev);
220 dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
221 return NETDEV_TX_BUSY;
224 * if buf_id < 3, then current frame will be send out of order,
225 * since buffer with lower id have higher priority (hell..)
227 netif_stop_queue(dev);
229 if (buf_id < priv->prev_buf_id) {
231 if (priv->cur_pri == 0xff) {
232 set_bit(F_TX_WAIT_ALL, &priv->flags);
233 netif_stop_queue(dev);
236 set_bit(F_TX_PROGRESS, &priv->flags);
239 priv->prev_buf_id = buf_id;
240 out_8(®s->cantbsel, i);
242 rtr = frame->can_id & CAN_RTR_FLAG;
244 /* RTR is always the lowest bit of interest, then IDs follow */
245 if (frame->can_id & CAN_EFF_FLAG) {
246 can_id = (frame->can_id & CAN_EFF_MASK)
247 << (MSCAN_EFF_RTR_SHIFT + 1);
249 can_id |= 1 << MSCAN_EFF_RTR_SHIFT;
250 out_be16(®s->tx.idr3_2, can_id);
253 /* EFF_FLAGS are inbetween the IDs :( */
254 can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0)
257 can_id = (frame->can_id & CAN_SFF_MASK)
258 << (MSCAN_SFF_RTR_SHIFT + 1);
260 can_id |= 1 << MSCAN_SFF_RTR_SHIFT;
262 out_be16(®s->tx.idr1_0, can_id);
265 void __iomem *data = ®s->tx.dsr1_0;
266 u16 *payload = (u16 *)frame->data;
268 /* It is safe to write into dsr[dlc+1] */
269 for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
270 out_be16(data, *payload++);
271 data += 2 + _MSCAN_RESERVED_DSR_SIZE;
275 out_8(®s->tx.dlr, frame->can_dlc);
276 out_8(®s->tx.tbpr, priv->cur_pri);
278 /* Start transmission. */
279 out_8(®s->cantflg, 1 << buf_id);
281 if (!test_bit(F_TX_PROGRESS, &priv->flags))
282 dev->trans_start = jiffies;
284 list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);
286 can_put_echo_skb(skb, dev, buf_id);
288 /* Enable interrupt. */
289 priv->tx_active |= 1 << buf_id;
290 out_8(®s->cantier, priv->tx_active);
295 /* This function returns the old state to see where we came from */
296 static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
298 struct mscan_priv *priv = netdev_priv(dev);
299 enum can_state state, old_state = priv->can.state;
301 if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
302 state = state_map[max(MSCAN_STATE_RX(canrflg),
303 MSCAN_STATE_TX(canrflg))];
304 priv->can.state = state;
309 static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
311 struct mscan_priv *priv = netdev_priv(dev);
312 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
316 can_id = in_be16(®s->rx.idr1_0);
317 if (can_id & (1 << 3)) {
318 frame->can_id = CAN_EFF_FLAG;
319 can_id = ((can_id << 16) | in_be16(®s->rx.idr3_2));
320 can_id = ((can_id & 0xffe00000) |
321 ((can_id & 0x7ffff) << 2)) >> 2;
327 frame->can_id |= can_id >> 1;
329 frame->can_id |= CAN_RTR_FLAG;
331 frame->can_dlc = get_can_dlc(in_8(®s->rx.dlr) & 0xf);
333 if (!(frame->can_id & CAN_RTR_FLAG)) {
334 void __iomem *data = ®s->rx.dsr1_0;
335 u16 *payload = (u16 *)frame->data;
337 for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
338 *payload++ = in_be16(data);
339 data += 2 + _MSCAN_RESERVED_DSR_SIZE;
343 out_8(®s->canrflg, MSCAN_RXF);
346 static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
349 struct mscan_priv *priv = netdev_priv(dev);
350 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
351 struct net_device_stats *stats = &dev->stats;
352 enum can_state old_state;
354 dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
355 frame->can_id = CAN_ERR_FLAG;
357 if (canrflg & MSCAN_OVRIF) {
358 frame->can_id |= CAN_ERR_CRTL;
359 frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
360 stats->rx_over_errors++;
366 old_state = check_set_state(dev, canrflg);
368 if (old_state != priv->can.state) {
369 switch (priv->can.state) {
370 case CAN_STATE_ERROR_WARNING:
371 frame->can_id |= CAN_ERR_CRTL;
372 priv->can.can_stats.error_warning++;
373 if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
374 (canrflg & MSCAN_RSTAT_MSK))
375 frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
376 if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
377 (canrflg & MSCAN_TSTAT_MSK))
378 frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
380 case CAN_STATE_ERROR_PASSIVE:
381 frame->can_id |= CAN_ERR_CRTL;
382 priv->can.can_stats.error_passive++;
383 frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
385 case CAN_STATE_BUS_OFF:
386 frame->can_id |= CAN_ERR_BUSOFF;
388 * The MSCAN on the MPC5200 does recover from bus-off
389 * automatically. To avoid that we stop the chip doing
390 * a light-weight stop (we are in irq-context).
392 if (priv->type != MSCAN_TYPE_MPC5121) {
393 out_8(®s->cantier, 0);
394 out_8(®s->canrier, 0);
395 setbits8(®s->canctl0,
396 MSCAN_SLPRQ | MSCAN_INITRQ);
404 priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
405 frame->can_dlc = CAN_ERR_DLC;
406 out_8(®s->canrflg, MSCAN_ERR_IF);
409 static int mscan_rx_poll(struct napi_struct *napi, int quota)
411 struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
412 struct net_device *dev = napi->dev;
413 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
414 struct net_device_stats *stats = &dev->stats;
418 struct can_frame *frame;
421 while (npackets < quota) {
422 canrflg = in_8(®s->canrflg);
423 if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))
426 skb = alloc_can_skb(dev, &frame);
428 if (printk_ratelimit())
429 dev_notice(dev->dev.parent, "packet dropped\n");
431 out_8(®s->canrflg, canrflg);
435 if (canrflg & MSCAN_RXF)
436 mscan_get_rx_frame(dev, frame);
437 else if (canrflg & MSCAN_ERR_IF)
438 mscan_get_err_frame(dev, frame, canrflg);
441 stats->rx_bytes += frame->can_dlc;
443 netif_receive_skb(skb);
446 if (!(in_8(®s->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
447 napi_complete(&priv->napi);
448 clear_bit(F_RX_PROGRESS, &priv->flags);
449 if (priv->can.state < CAN_STATE_BUS_OFF)
450 out_8(®s->canrier, priv->shadow_canrier);
456 static irqreturn_t mscan_isr(int irq, void *dev_id)
458 struct net_device *dev = (struct net_device *)dev_id;
459 struct mscan_priv *priv = netdev_priv(dev);
460 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
461 struct net_device_stats *stats = &dev->stats;
462 u8 cantier, cantflg, canrflg;
463 irqreturn_t ret = IRQ_NONE;
465 cantier = in_8(®s->cantier) & MSCAN_TXE;
466 cantflg = in_8(®s->cantflg) & cantier;
468 if (cantier && cantflg) {
469 struct list_head *tmp, *pos;
471 list_for_each_safe(pos, tmp, &priv->tx_head) {
472 struct tx_queue_entry *entry =
473 list_entry(pos, struct tx_queue_entry, list);
474 u8 mask = entry->mask;
476 if (!(cantflg & mask))
479 out_8(®s->cantbsel, mask);
480 stats->tx_bytes += in_8(®s->tx.dlr);
482 can_get_echo_skb(dev, entry->id);
483 priv->tx_active &= ~mask;
487 if (list_empty(&priv->tx_head)) {
488 clear_bit(F_TX_WAIT_ALL, &priv->flags);
489 clear_bit(F_TX_PROGRESS, &priv->flags);
492 dev->trans_start = jiffies;
495 if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
496 netif_wake_queue(dev);
498 out_8(®s->cantier, priv->tx_active);
502 canrflg = in_8(®s->canrflg);
503 if ((canrflg & ~MSCAN_STAT_MSK) &&
504 !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
505 if (canrflg & ~MSCAN_STAT_MSK) {
506 priv->shadow_canrier = in_8(®s->canrier);
507 out_8(®s->canrier, 0);
508 napi_schedule(&priv->napi);
511 clear_bit(F_RX_PROGRESS, &priv->flags);
517 static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
519 struct mscan_priv *priv = netdev_priv(dev);
522 if (!priv->open_time)
527 ret = mscan_restart(dev);
530 if (netif_queue_stopped(dev))
531 netif_wake_queue(dev);
541 static int mscan_do_set_bittiming(struct net_device *dev)
543 struct mscan_priv *priv = netdev_priv(dev);
544 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
545 struct can_bittiming *bt = &priv->can.bittiming;
548 btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
549 btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
550 BTR1_SET_TSEG2(bt->phase_seg2) |
551 BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
553 dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
556 out_8(®s->canbtr0, btr0);
557 out_8(®s->canbtr1, btr1);
562 static int mscan_open(struct net_device *dev)
565 struct mscan_priv *priv = netdev_priv(dev);
566 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
569 ret = open_candev(dev);
573 napi_enable(&priv->napi);
575 ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
577 dev_err(dev->dev.parent, "failed to attach interrupt\n");
578 goto exit_napi_disable;
581 priv->open_time = jiffies;
583 clrbits8(®s->canctl1, MSCAN_LISTEN);
585 ret = mscan_start(dev);
589 netif_start_queue(dev);
595 free_irq(dev->irq, dev);
597 napi_disable(&priv->napi);
602 static int mscan_close(struct net_device *dev)
604 struct mscan_priv *priv = netdev_priv(dev);
605 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
607 netif_stop_queue(dev);
608 napi_disable(&priv->napi);
610 out_8(®s->cantier, 0);
611 out_8(®s->canrier, 0);
612 mscan_set_mode(dev, MSCAN_INIT_MODE);
614 free_irq(dev->irq, dev);
620 static const struct net_device_ops mscan_netdev_ops = {
621 .ndo_open = mscan_open,
622 .ndo_stop = mscan_close,
623 .ndo_start_xmit = mscan_start_xmit,
626 int register_mscandev(struct net_device *dev, int mscan_clksrc)
628 struct mscan_priv *priv = netdev_priv(dev);
629 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
632 ctl1 = in_8(®s->canctl1);
634 ctl1 |= MSCAN_CLKSRC;
636 ctl1 &= ~MSCAN_CLKSRC;
638 if (priv->type == MSCAN_TYPE_MPC5121)
639 ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */
642 out_8(®s->canctl1, ctl1);
645 /* acceptance mask/acceptance code (accept everything) */
646 out_be16(®s->canidar1_0, 0);
647 out_be16(®s->canidar3_2, 0);
648 out_be16(®s->canidar5_4, 0);
649 out_be16(®s->canidar7_6, 0);
651 out_be16(®s->canidmr1_0, 0xffff);
652 out_be16(®s->canidmr3_2, 0xffff);
653 out_be16(®s->canidmr5_4, 0xffff);
654 out_be16(®s->canidmr7_6, 0xffff);
655 /* Two 32 bit Acceptance Filters */
656 out_8(®s->canidac, MSCAN_AF_32BIT);
658 mscan_set_mode(dev, MSCAN_INIT_MODE);
660 return register_candev(dev);
663 void unregister_mscandev(struct net_device *dev)
665 struct mscan_priv *priv = netdev_priv(dev);
666 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
667 mscan_set_mode(dev, MSCAN_INIT_MODE);
668 clrbits8(®s->canctl1, MSCAN_CANE);
669 unregister_candev(dev);
672 struct net_device *alloc_mscandev(void)
674 struct net_device *dev;
675 struct mscan_priv *priv;
678 dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
681 priv = netdev_priv(dev);
683 dev->netdev_ops = &mscan_netdev_ops;
685 dev->flags |= IFF_ECHO; /* we support local echo */
687 netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
689 priv->can.bittiming_const = &mscan_bittiming_const;
690 priv->can.do_set_bittiming = mscan_do_set_bittiming;
691 priv->can.do_set_mode = mscan_do_set_mode;
693 for (i = 0; i < TX_QUEUE_SIZE; i++) {
694 priv->tx_queue[i].id = i;
695 priv->tx_queue[i].mask = 1 << i;
701 MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
702 MODULE_LICENSE("GPL v2");
703 MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");