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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#include <linux/pm_runtime.h>
38#include <linux/pinctrl/consumer.h>
39
40#include <linux/can.h>
41#include <linux/can/dev.h>
42#include <linux/can/error.h>
43#include <linux/can/led.h>
44
45#include "c_can.h"
46
47/* Number of interface registers */
48#define IF_ENUM_REG_LEN 11
49#define C_CAN_IFACE(reg, iface) (C_CAN_IF1_##reg + (iface) * IF_ENUM_REG_LEN)
50
51/* control extension register D_CAN specific */
52#define CONTROL_EX_PDR BIT(8)
53
54/* control register */
55#define CONTROL_SWR BIT(15)
56#define CONTROL_TEST BIT(7)
57#define CONTROL_CCE BIT(6)
58#define CONTROL_DISABLE_AR BIT(5)
59#define CONTROL_ENABLE_AR (0 << 5)
60#define CONTROL_EIE BIT(3)
61#define CONTROL_SIE BIT(2)
62#define CONTROL_IE BIT(1)
63#define CONTROL_INIT BIT(0)
64
65#define CONTROL_IRQMSK (CONTROL_EIE | CONTROL_IE | CONTROL_SIE)
66
67/* test register */
68#define TEST_RX BIT(7)
69#define TEST_TX1 BIT(6)
70#define TEST_TX2 BIT(5)
71#define TEST_LBACK BIT(4)
72#define TEST_SILENT BIT(3)
73#define TEST_BASIC BIT(2)
74
75/* status register */
76#define STATUS_PDA BIT(10)
77#define STATUS_BOFF BIT(7)
78#define STATUS_EWARN BIT(6)
79#define STATUS_EPASS BIT(5)
80#define STATUS_RXOK BIT(4)
81#define STATUS_TXOK BIT(3)
82
83/* error counter register */
84#define ERR_CNT_TEC_MASK 0xff
85#define ERR_CNT_TEC_SHIFT 0
86#define ERR_CNT_REC_SHIFT 8
87#define ERR_CNT_REC_MASK (0x7f << ERR_CNT_REC_SHIFT)
88#define ERR_CNT_RP_SHIFT 15
89#define ERR_CNT_RP_MASK (0x1 << ERR_CNT_RP_SHIFT)
90
91/* bit-timing register */
92#define BTR_BRP_MASK 0x3f
93#define BTR_BRP_SHIFT 0
94#define BTR_SJW_SHIFT 6
95#define BTR_SJW_MASK (0x3 << BTR_SJW_SHIFT)
96#define BTR_TSEG1_SHIFT 8
97#define BTR_TSEG1_MASK (0xf << BTR_TSEG1_SHIFT)
98#define BTR_TSEG2_SHIFT 12
99#define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT)
100
101/* interrupt register */
102#define INT_STS_PENDING 0x8000
103
104/* brp extension register */
105#define BRP_EXT_BRPE_MASK 0x0f
106#define BRP_EXT_BRPE_SHIFT 0
107
108/* IFx command request */
109#define IF_COMR_BUSY BIT(15)
110
111/* IFx command mask */
112#define IF_COMM_WR BIT(7)
113#define IF_COMM_MASK BIT(6)
114#define IF_COMM_ARB BIT(5)
115#define IF_COMM_CONTROL BIT(4)
116#define IF_COMM_CLR_INT_PND BIT(3)
117#define IF_COMM_TXRQST BIT(2)
118#define IF_COMM_CLR_NEWDAT IF_COMM_TXRQST
119#define IF_COMM_DATAA BIT(1)
120#define IF_COMM_DATAB BIT(0)
121
122/* TX buffer setup */
123#define IF_COMM_TX (IF_COMM_ARB | IF_COMM_CONTROL | \
124 IF_COMM_TXRQST | \
125 IF_COMM_DATAA | IF_COMM_DATAB)
126
127/* For the low buffers we clear the interrupt bit, but keep newdat */
128#define IF_COMM_RCV_LOW (IF_COMM_MASK | IF_COMM_ARB | \
129 IF_COMM_CONTROL | IF_COMM_CLR_INT_PND | \
130 IF_COMM_DATAA | IF_COMM_DATAB)
131
132/* For the high buffers we clear the interrupt bit and newdat */
133#define IF_COMM_RCV_HIGH (IF_COMM_RCV_LOW | IF_COMM_CLR_NEWDAT)
134
135
136/* Receive setup of message objects */
137#define IF_COMM_RCV_SETUP (IF_COMM_MASK | IF_COMM_ARB | IF_COMM_CONTROL)
138
139/* Invalidation of message objects */
140#define IF_COMM_INVAL (IF_COMM_ARB | IF_COMM_CONTROL)
141
142/* IFx arbitration */
143#define IF_ARB_MSGVAL BIT(31)
144#define IF_ARB_MSGXTD BIT(30)
145#define IF_ARB_TRANSMIT BIT(29)
146
147/* IFx message control */
148#define IF_MCONT_NEWDAT BIT(15)
149#define IF_MCONT_MSGLST BIT(14)
150#define IF_MCONT_INTPND BIT(13)
151#define IF_MCONT_UMASK BIT(12)
152#define IF_MCONT_TXIE BIT(11)
153#define IF_MCONT_RXIE BIT(10)
154#define IF_MCONT_RMTEN BIT(9)
155#define IF_MCONT_TXRQST BIT(8)
156#define IF_MCONT_EOB BIT(7)
157#define IF_MCONT_DLC_MASK 0xf
158
159#define IF_MCONT_RCV (IF_MCONT_RXIE | IF_MCONT_UMASK)
160#define IF_MCONT_RCV_EOB (IF_MCONT_RCV | IF_MCONT_EOB)
161
162#define IF_MCONT_TX (IF_MCONT_TXIE | IF_MCONT_EOB)
163
164/*
165 * Use IF1 for RX and IF2 for TX
166 */
167#define IF_RX 0
168#define IF_TX 1
169
170/* minimum timeout for checking BUSY status */
171#define MIN_TIMEOUT_VALUE 6
172
173/* Wait for ~1 sec for INIT bit */
174#define INIT_WAIT_MS 1000
175
176/* napi related */
177#define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM
178
179/* c_can lec values */
180enum c_can_lec_type {
181 LEC_NO_ERROR = 0,
182 LEC_STUFF_ERROR,
183 LEC_FORM_ERROR,
184 LEC_ACK_ERROR,
185 LEC_BIT1_ERROR,
186 LEC_BIT0_ERROR,
187 LEC_CRC_ERROR,
188 LEC_UNUSED,
189 LEC_MASK = LEC_UNUSED,
190};
191
192/*
193 * c_can error types:
194 * Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported
195 */
196enum c_can_bus_error_types {
197 C_CAN_NO_ERROR = 0,
198 C_CAN_BUS_OFF,
199 C_CAN_ERROR_WARNING,
200 C_CAN_ERROR_PASSIVE,
201};
202
203static const struct can_bittiming_const c_can_bittiming_const = {
204 .name = KBUILD_MODNAME,
205 .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */
206 .tseg1_max = 16,
207 .tseg2_min = 1, /* Time segment 2 = phase_seg2 */
208 .tseg2_max = 8,
209 .sjw_max = 4,
210 .brp_min = 1,
211 .brp_max = 1024, /* 6-bit BRP field + 4-bit BRPE field*/
212 .brp_inc = 1,
213};
214
215static inline void c_can_pm_runtime_enable(const struct c_can_priv *priv)
216{
217 if (priv->device)
218 pm_runtime_enable(priv->device);
219}
220
221static inline void c_can_pm_runtime_disable(const struct c_can_priv *priv)
222{
223 if (priv->device)
224 pm_runtime_disable(priv->device);
225}
226
227static inline void c_can_pm_runtime_get_sync(const struct c_can_priv *priv)
228{
229 if (priv->device)
230 pm_runtime_get_sync(priv->device);
231}
232
233static inline void c_can_pm_runtime_put_sync(const struct c_can_priv *priv)
234{
235 if (priv->device)
236 pm_runtime_put_sync(priv->device);
237}
238
239static inline void c_can_reset_ram(const struct c_can_priv *priv, bool enable)
240{
241 if (priv->raminit)
242 priv->raminit(priv, enable);
243}
244
245static void c_can_irq_control(struct c_can_priv *priv, bool enable)
246{
247 u32 ctrl = priv->read_reg(priv, C_CAN_CTRL_REG) & ~CONTROL_IRQMSK;
248
249 if (enable)
250 ctrl |= CONTROL_IRQMSK;
251
252 priv->write_reg(priv, C_CAN_CTRL_REG, ctrl);
253}
254
255static void c_can_obj_update(struct net_device *dev, int iface, u32 cmd, u32 obj)
256{
257 struct c_can_priv *priv = netdev_priv(dev);
258 int cnt, reg = C_CAN_IFACE(COMREQ_REG, iface);
259
260 priv->write_reg32(priv, reg, (cmd << 16) | obj);
261
262 for (cnt = MIN_TIMEOUT_VALUE; cnt; cnt--) {
263 if (!(priv->read_reg(priv, reg) & IF_COMR_BUSY))
264 return;
265 udelay(1);
266 }
267 netdev_err(dev, "Updating object timed out\n");
268
269}
270
271static inline void c_can_object_get(struct net_device *dev, int iface,
272 u32 obj, u32 cmd)
273{
274 c_can_obj_update(dev, iface, cmd, obj);
275}
276
277static inline void c_can_object_put(struct net_device *dev, int iface,
278 u32 obj, u32 cmd)
279{
280 c_can_obj_update(dev, iface, cmd | IF_COMM_WR, obj);
281}
282
283/*
284 * Note: According to documentation clearing TXIE while MSGVAL is set
285 * is not allowed, but works nicely on C/DCAN. And that lowers the I/O
286 * load significantly.
287 */
288static void c_can_inval_tx_object(struct net_device *dev, int iface, int obj)
289{
290 struct c_can_priv *priv = netdev_priv(dev);
291
292 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), 0);
293 c_can_object_put(dev, iface, obj, IF_COMM_INVAL);
294}
295
296static void c_can_inval_msg_object(struct net_device *dev, int iface, int obj)
297{
298 struct c_can_priv *priv = netdev_priv(dev);
299
300 priv->write_reg(priv, C_CAN_IFACE(ARB1_REG, iface), 0);
301 priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface), 0);
302 c_can_inval_tx_object(dev, iface, obj);
303}
304
305static void c_can_setup_tx_object(struct net_device *dev, int iface,
306 struct can_frame *frame, int idx)
307{
308 struct c_can_priv *priv = netdev_priv(dev);
309 u16 ctrl = IF_MCONT_TX | frame->can_dlc;
310 bool rtr = frame->can_id & CAN_RTR_FLAG;
311 u32 arb = IF_ARB_MSGVAL;
312 int i;
313
314 if (frame->can_id & CAN_EFF_FLAG) {
315 arb |= frame->can_id & CAN_EFF_MASK;
316 arb |= IF_ARB_MSGXTD;
317 } else {
318 arb |= (frame->can_id & CAN_SFF_MASK) << 18;
319 }
320
321 if (!rtr)
322 arb |= IF_ARB_TRANSMIT;
323
324 /*
325 * If we change the DIR bit, we need to invalidate the buffer
326 * first, i.e. clear the MSGVAL flag in the arbiter.
327 */
328 if (rtr != (bool)test_bit(idx, &priv->tx_dir)) {
329 u32 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
330
331 c_can_inval_msg_object(dev, iface, obj);
332 change_bit(idx, &priv->tx_dir);
333 }
334
335 priv->write_reg32(priv, C_CAN_IFACE(ARB1_REG, iface), arb);
336
337 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), ctrl);
338
339 if (priv->type == BOSCH_D_CAN) {
340 u32 data = 0, dreg = C_CAN_IFACE(DATA1_REG, iface);
341
342 for (i = 0; i < frame->can_dlc; i += 4, dreg += 2) {
343 data = (u32)frame->data[i];
344 data |= (u32)frame->data[i + 1] << 8;
345 data |= (u32)frame->data[i + 2] << 16;
346 data |= (u32)frame->data[i + 3] << 24;
347 priv->write_reg32(priv, dreg, data);
348 }
349 } else {
350 for (i = 0; i < frame->can_dlc; i += 2) {
351 priv->write_reg(priv,
352 C_CAN_IFACE(DATA1_REG, iface) + i / 2,
353 frame->data[i] |
354 (frame->data[i + 1] << 8));
355 }
356 }
357}
358
359static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev,
360 int iface)
361{
362 int i;
363
364 for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_MSG_RX_LOW_LAST; i++)
365 c_can_object_get(dev, iface, i, IF_COMM_CLR_NEWDAT);
366}
367
368static int c_can_handle_lost_msg_obj(struct net_device *dev,
369 int iface, int objno, u32 ctrl)
370{
371 struct net_device_stats *stats = &dev->stats;
372 struct c_can_priv *priv = netdev_priv(dev);
373 struct can_frame *frame;
374 struct sk_buff *skb;
375
376 ctrl &= ~(IF_MCONT_MSGLST | IF_MCONT_INTPND | IF_MCONT_NEWDAT);
377 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), ctrl);
378 c_can_object_put(dev, iface, objno, IF_COMM_CONTROL);
379
380 stats->rx_errors++;
381 stats->rx_over_errors++;
382
383 /* create an error msg */
384 skb = alloc_can_err_skb(dev, &frame);
385 if (unlikely(!skb))
386 return 0;
387
388 frame->can_id |= CAN_ERR_CRTL;
389 frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
390
391 netif_receive_skb(skb);
392 return 1;
393}
394
395static int c_can_read_msg_object(struct net_device *dev, int iface, u32 ctrl)
396{
397 struct net_device_stats *stats = &dev->stats;
398 struct c_can_priv *priv = netdev_priv(dev);
399 struct can_frame *frame;
400 struct sk_buff *skb;
401 u32 arb, data;
402
403 skb = alloc_can_skb(dev, &frame);
404 if (!skb) {
405 stats->rx_dropped++;
406 return -ENOMEM;
407 }
408
409 frame->can_dlc = get_can_dlc(ctrl & 0x0F);
410
411 arb = priv->read_reg32(priv, C_CAN_IFACE(ARB1_REG, iface));
412
413 if (arb & IF_ARB_MSGXTD)
414 frame->can_id = (arb & CAN_EFF_MASK) | CAN_EFF_FLAG;
415 else
416 frame->can_id = (arb >> 18) & CAN_SFF_MASK;
417
418 if (arb & IF_ARB_TRANSMIT) {
419 frame->can_id |= CAN_RTR_FLAG;
420 } else {
421 int i, dreg = C_CAN_IFACE(DATA1_REG, iface);
422
423 if (priv->type == BOSCH_D_CAN) {
424 for (i = 0; i < frame->can_dlc; i += 4, dreg += 2) {
425 data = priv->read_reg32(priv, dreg);
426 frame->data[i] = data;
427 frame->data[i + 1] = data >> 8;
428 frame->data[i + 2] = data >> 16;
429 frame->data[i + 3] = data >> 24;
430 }
431 } else {
432 for (i = 0; i < frame->can_dlc; i += 2, dreg++) {
433 data = priv->read_reg(priv, dreg);
434 frame->data[i] = data;
435 frame->data[i + 1] = data >> 8;
436 }
437 }
438 }
439
440 stats->rx_packets++;
441 stats->rx_bytes += frame->can_dlc;
442
443 netif_receive_skb(skb);
444 return 0;
445}
446
447static void c_can_setup_receive_object(struct net_device *dev, int iface,
448 u32 obj, u32 mask, u32 id, u32 mcont)
449{
450 struct c_can_priv *priv = netdev_priv(dev);
451
452 mask |= BIT(29);
453 priv->write_reg32(priv, C_CAN_IFACE(MASK1_REG, iface), mask);
454
455 id |= IF_ARB_MSGVAL;
456 priv->write_reg32(priv, C_CAN_IFACE(ARB1_REG, iface), id);
457
458 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), mcont);
459 c_can_object_put(dev, iface, obj, IF_COMM_RCV_SETUP);
460}
461
462static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
463 struct net_device *dev)
464{
465 struct can_frame *frame = (struct can_frame *)skb->data;
466 struct c_can_priv *priv = netdev_priv(dev);
467 u32 idx, obj;
468
469 if (can_dropped_invalid_skb(dev, skb))
470 return NETDEV_TX_OK;
471 /*
472 * This is not a FIFO. C/D_CAN sends out the buffers
473 * prioritized. The lowest buffer number wins.
474 */
475 idx = fls(atomic_read(&priv->tx_active));
476 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
477
478 /* If this is the last buffer, stop the xmit queue */
479 if (idx == C_CAN_MSG_OBJ_TX_NUM - 1)
480 netif_stop_queue(dev);
481 /*
482 * Store the message in the interface so we can call
483 * can_put_echo_skb(). We must do this before we enable
484 * transmit as we might race against do_tx().
485 */
486 c_can_setup_tx_object(dev, IF_TX, frame, idx);
487 priv->dlc[idx] = frame->can_dlc;
488 can_put_echo_skb(skb, dev, idx);
489
490 /* Update the active bits */
491 atomic_add((1 << idx), &priv->tx_active);
492 /* Start transmission */
493 c_can_object_put(dev, IF_TX, obj, IF_COMM_TX);
494
495 return NETDEV_TX_OK;
496}
497
498static int c_can_wait_for_ctrl_init(struct net_device *dev,
499 struct c_can_priv *priv, u32 init)
500{
501 int retry = 0;
502
503 while (init != (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_INIT)) {
504 udelay(10);
505 if (retry++ > 1000) {
506 netdev_err(dev, "CCTRL: set CONTROL_INIT failed\n");
507 return -EIO;
508 }
509 }
510 return 0;
511}
512
513static int c_can_set_bittiming(struct net_device *dev)
514{
515 unsigned int reg_btr, reg_brpe, ctrl_save;
516 u8 brp, brpe, sjw, tseg1, tseg2;
517 u32 ten_bit_brp;
518 struct c_can_priv *priv = netdev_priv(dev);
519 const struct can_bittiming *bt = &priv->can.bittiming;
520 int res;
521
522 /* c_can provides a 6-bit brp and 4-bit brpe fields */
523 ten_bit_brp = bt->brp - 1;
524 brp = ten_bit_brp & BTR_BRP_MASK;
525 brpe = ten_bit_brp >> 6;
526
527 sjw = bt->sjw - 1;
528 tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
529 tseg2 = bt->phase_seg2 - 1;
530 reg_btr = brp | (sjw << BTR_SJW_SHIFT) | (tseg1 << BTR_TSEG1_SHIFT) |
531 (tseg2 << BTR_TSEG2_SHIFT);
532 reg_brpe = brpe & BRP_EXT_BRPE_MASK;
533
534 netdev_info(dev,
535 "setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe);
536
537 ctrl_save = priv->read_reg(priv, C_CAN_CTRL_REG);
538 ctrl_save &= ~CONTROL_INIT;
539 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_CCE | CONTROL_INIT);
540 res = c_can_wait_for_ctrl_init(dev, priv, CONTROL_INIT);
541 if (res)
542 return res;
543
544 priv->write_reg(priv, C_CAN_BTR_REG, reg_btr);
545 priv->write_reg(priv, C_CAN_BRPEXT_REG, reg_brpe);
546 priv->write_reg(priv, C_CAN_CTRL_REG, ctrl_save);
547
548 return c_can_wait_for_ctrl_init(dev, priv, 0);
549}
550
551/*
552 * Configure C_CAN message objects for Tx and Rx purposes:
553 * C_CAN provides a total of 32 message objects that can be configured
554 * either for Tx or Rx purposes. Here the first 16 message objects are used as
555 * a reception FIFO. The end of reception FIFO is signified by the EoB bit
556 * being SET. The remaining 16 message objects are kept aside for Tx purposes.
557 * See user guide document for further details on configuring message
558 * objects.
559 */
560static void c_can_configure_msg_objects(struct net_device *dev)
561{
562 int i;
563
564 /* first invalidate all message objects */
565 for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
566 c_can_inval_msg_object(dev, IF_RX, i);
567
568 /* setup receive message objects */
569 for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
570 c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV);
571
572 c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
573 IF_MCONT_RCV_EOB);
574}
575
576static int c_can_software_reset(struct net_device *dev)
577{
578 struct c_can_priv *priv = netdev_priv(dev);
579 int retry = 0;
580
581 if (priv->type != BOSCH_D_CAN)
582 return 0;
583
584 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_SWR | CONTROL_INIT);
585 while (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_SWR) {
586 msleep(20);
587 if (retry++ > 100) {
588 netdev_err(dev, "CCTRL: software reset failed\n");
589 return -EIO;
590 }
591 }
592
593 return 0;
594}
595
596/*
597 * Configure C_CAN chip:
598 * - enable/disable auto-retransmission
599 * - set operating mode
600 * - configure message objects
601 */
602static int c_can_chip_config(struct net_device *dev)
603{
604 struct c_can_priv *priv = netdev_priv(dev);
605 int err;
606
607 err = c_can_software_reset(dev);
608 if (err)
609 return err;
610
611 /* enable automatic retransmission */
612 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR);
613
614 if ((priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) &&
615 (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)) {
616 /* loopback + silent mode : useful for hot self-test */
617 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
618 priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK | TEST_SILENT);
619 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
620 /* loopback mode : useful for self-test function */
621 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
622 priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK);
623 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
624 /* silent mode : bus-monitoring mode */
625 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
626 priv->write_reg(priv, C_CAN_TEST_REG, TEST_SILENT);
627 }
628
629 /* configure message objects */
630 c_can_configure_msg_objects(dev);
631
632 /* set a `lec` value so that we can check for updates later */
633 priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED);
634
635 /* Clear all internal status */
636 atomic_set(&priv->tx_active, 0);
637 priv->rxmasked = 0;
638 priv->tx_dir = 0;
639
640 /* set bittiming params */
641 return c_can_set_bittiming(dev);
642}
643
644static int c_can_start(struct net_device *dev)
645{
646 struct c_can_priv *priv = netdev_priv(dev);
647 int err;
648 struct pinctrl *p;
649
650 /* basic c_can configuration */
651 err = c_can_chip_config(dev);
652 if (err)
653 return err;
654
655 /* Setup the command for new messages */
656 priv->comm_rcv_high = priv->type != BOSCH_D_CAN ?
657 IF_COMM_RCV_LOW : IF_COMM_RCV_HIGH;
658
659 priv->can.state = CAN_STATE_ERROR_ACTIVE;
660
661 /* Attempt to use "active" if available else use "default" */
662 p = pinctrl_get_select(priv->device, "active");
663 if (!IS_ERR(p))
664 pinctrl_put(p);
665 else
666 pinctrl_pm_select_default_state(priv->device);
667
668 return 0;
669}
670
671static void c_can_stop(struct net_device *dev)
672{
673 struct c_can_priv *priv = netdev_priv(dev);
674
675 c_can_irq_control(priv, false);
676
677 /* put ctrl to init on stop to end ongoing transmission */
678 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_INIT);
679
680 /* deactivate pins */
681 pinctrl_pm_select_sleep_state(dev->dev.parent);
682 priv->can.state = CAN_STATE_STOPPED;
683}
684
685static int c_can_set_mode(struct net_device *dev, enum can_mode mode)
686{
687 struct c_can_priv *priv = netdev_priv(dev);
688 int err;
689
690 switch (mode) {
691 case CAN_MODE_START:
692 err = c_can_start(dev);
693 if (err)
694 return err;
695 netif_wake_queue(dev);
696 c_can_irq_control(priv, true);
697 break;
698 default:
699 return -EOPNOTSUPP;
700 }
701
702 return 0;
703}
704
705static int __c_can_get_berr_counter(const struct net_device *dev,
706 struct can_berr_counter *bec)
707{
708 unsigned int reg_err_counter;
709 struct c_can_priv *priv = netdev_priv(dev);
710
711 reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG);
712 bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >>
713 ERR_CNT_REC_SHIFT;
714 bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK;
715
716 return 0;
717}
718
719static int c_can_get_berr_counter(const struct net_device *dev,
720 struct can_berr_counter *bec)
721{
722 struct c_can_priv *priv = netdev_priv(dev);
723 int err;
724
725 c_can_pm_runtime_get_sync(priv);
726 err = __c_can_get_berr_counter(dev, bec);
727 c_can_pm_runtime_put_sync(priv);
728
729 return err;
730}
731
732static void c_can_do_tx(struct net_device *dev)
733{
734 struct c_can_priv *priv = netdev_priv(dev);
735 struct net_device_stats *stats = &dev->stats;
736 u32 idx, obj, pkts = 0, bytes = 0, pend, clr;
737
738 clr = pend = priv->read_reg(priv, C_CAN_INTPND2_REG);
739
740 while ((idx = ffs(pend))) {
741 idx--;
742 pend &= ~(1 << idx);
743 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
744 c_can_inval_tx_object(dev, IF_RX, obj);
745 can_get_echo_skb(dev, idx);
746 bytes += priv->dlc[idx];
747 pkts++;
748 }
749
750 /* Clear the bits in the tx_active mask */
751 atomic_sub(clr, &priv->tx_active);
752
753 if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))
754 netif_wake_queue(dev);
755
756 if (pkts) {
757 stats->tx_bytes += bytes;
758 stats->tx_packets += pkts;
759 can_led_event(dev, CAN_LED_EVENT_TX);
760 }
761}
762
763/*
764 * If we have a gap in the pending bits, that means we either
765 * raced with the hardware or failed to readout all upper
766 * objects in the last run due to quota limit.
767 */
768static u32 c_can_adjust_pending(u32 pend)
769{
770 u32 weight, lasts;
771
772 if (pend == RECEIVE_OBJECT_BITS)
773 return pend;
774
775 /*
776 * If the last set bit is larger than the number of pending
777 * bits we have a gap.
778 */
779 weight = hweight32(pend);
780 lasts = fls(pend);
781
782 /* If the bits are linear, nothing to do */
783 if (lasts == weight)
784 return pend;
785
786 /*
787 * Find the first set bit after the gap. We walk backwards
788 * from the last set bit.
789 */
790 for (lasts--; pend & (1 << (lasts - 1)); lasts--);
791
792 return pend & ~((1 << lasts) - 1);
793}
794
795static inline void c_can_rx_object_get(struct net_device *dev,
796 struct c_can_priv *priv, u32 obj)
797{
798 c_can_object_get(dev, IF_RX, obj, priv->comm_rcv_high);
799}
800
801static inline void c_can_rx_finalize(struct net_device *dev,
802 struct c_can_priv *priv, u32 obj)
803{
804 if (priv->type != BOSCH_D_CAN)
805 c_can_object_get(dev, IF_RX, obj, IF_COMM_CLR_NEWDAT);
806}
807
808static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv,
809 u32 pend, int quota)
810{
811 u32 pkts = 0, ctrl, obj;
812
813 while ((obj = ffs(pend)) && quota > 0) {
814 pend &= ~BIT(obj - 1);
815
816 c_can_rx_object_get(dev, priv, obj);
817 ctrl = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, IF_RX));
818
819 if (ctrl & IF_MCONT_MSGLST) {
820 int n = c_can_handle_lost_msg_obj(dev, IF_RX, obj, ctrl);
821
822 pkts += n;
823 quota -= n;
824 continue;
825 }
826
827 /*
828 * This really should not happen, but this covers some
829 * odd HW behaviour. Do not remove that unless you
830 * want to brick your machine.
831 */
832 if (!(ctrl & IF_MCONT_NEWDAT))
833 continue;
834
835 /* read the data from the message object */
836 c_can_read_msg_object(dev, IF_RX, ctrl);
837
838 c_can_rx_finalize(dev, priv, obj);
839
840 pkts++;
841 quota--;
842 }
843
844 return pkts;
845}
846
847static inline u32 c_can_get_pending(struct c_can_priv *priv)
848{
849 u32 pend = priv->read_reg(priv, C_CAN_NEWDAT1_REG);
850
851 return pend;
852}
853
854/*
855 * theory of operation:
856 *
857 * c_can core saves a received CAN message into the first free message
858 * object it finds free (starting with the lowest). Bits NEWDAT and
859 * INTPND are set for this message object indicating that a new message
860 * has arrived. To work-around this issue, we keep two groups of message
861 * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT.
862 *
863 * We clear the newdat bit right away.
864 *
865 * This can result in packet reordering when the readout is slow.
866 */
867static int c_can_do_rx_poll(struct net_device *dev, int quota)
868{
869 struct c_can_priv *priv = netdev_priv(dev);
870 u32 pkts = 0, pend = 0, toread, n;
871
872 /*
873 * It is faster to read only one 16bit register. This is only possible
874 * for a maximum number of 16 objects.
875 */
876 BUILD_BUG_ON_MSG(C_CAN_MSG_OBJ_RX_LAST > 16,
877 "Implementation does not support more message objects than 16");
878
879 while (quota > 0) {
880 if (!pend) {
881 pend = c_can_get_pending(priv);
882 if (!pend)
883 break;
884 /*
885 * If the pending field has a gap, handle the
886 * bits above the gap first.
887 */
888 toread = c_can_adjust_pending(pend);
889 } else {
890 toread = pend;
891 }
892 /* Remove the bits from pend */
893 pend &= ~toread;
894 /* Read the objects */
895 n = c_can_read_objects(dev, priv, toread, quota);
896 pkts += n;
897 quota -= n;
898 }
899
900 if (pkts)
901 can_led_event(dev, CAN_LED_EVENT_RX);
902
903 return pkts;
904}
905
906static int c_can_handle_state_change(struct net_device *dev,
907 enum c_can_bus_error_types error_type)
908{
909 unsigned int reg_err_counter;
910 unsigned int rx_err_passive;
911 struct c_can_priv *priv = netdev_priv(dev);
912 struct net_device_stats *stats = &dev->stats;
913 struct can_frame *cf;
914 struct sk_buff *skb;
915 struct can_berr_counter bec;
916
917 switch (error_type) {
918 case C_CAN_NO_ERROR:
919 priv->can.state = CAN_STATE_ERROR_ACTIVE;
920 break;
921 case C_CAN_ERROR_WARNING:
922 /* error warning state */
923 priv->can.can_stats.error_warning++;
924 priv->can.state = CAN_STATE_ERROR_WARNING;
925 break;
926 case C_CAN_ERROR_PASSIVE:
927 /* error passive state */
928 priv->can.can_stats.error_passive++;
929 priv->can.state = CAN_STATE_ERROR_PASSIVE;
930 break;
931 case C_CAN_BUS_OFF:
932 /* bus-off state */
933 priv->can.state = CAN_STATE_BUS_OFF;
934 priv->can.can_stats.bus_off++;
935 break;
936 default:
937 break;
938 }
939
940 /* propagate the error condition to the CAN stack */
941 skb = alloc_can_err_skb(dev, &cf);
942 if (unlikely(!skb))
943 return 0;
944
945 __c_can_get_berr_counter(dev, &bec);
946 reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG);
947 rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >>
948 ERR_CNT_RP_SHIFT;
949
950 switch (error_type) {
951 case C_CAN_NO_ERROR:
952 /* error warning state */
953 cf->can_id |= CAN_ERR_CRTL;
954 cf->data[1] = CAN_ERR_CRTL_ACTIVE;
955 cf->data[6] = bec.txerr;
956 cf->data[7] = bec.rxerr;
957 break;
958 case C_CAN_ERROR_WARNING:
959 /* error warning state */
960 cf->can_id |= CAN_ERR_CRTL;
961 cf->data[1] = (bec.txerr > bec.rxerr) ?
962 CAN_ERR_CRTL_TX_WARNING :
963 CAN_ERR_CRTL_RX_WARNING;
964 cf->data[6] = bec.txerr;
965 cf->data[7] = bec.rxerr;
966
967 break;
968 case C_CAN_ERROR_PASSIVE:
969 /* error passive state */
970 cf->can_id |= CAN_ERR_CRTL;
971 if (rx_err_passive)
972 cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
973 if (bec.txerr > 127)
974 cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
975
976 cf->data[6] = bec.txerr;
977 cf->data[7] = bec.rxerr;
978 break;
979 case C_CAN_BUS_OFF:
980 /* bus-off state */
981 cf->can_id |= CAN_ERR_BUSOFF;
982 can_bus_off(dev);
983 break;
984 default:
985 break;
986 }
987
988 stats->rx_packets++;
989 stats->rx_bytes += cf->can_dlc;
990 netif_receive_skb(skb);
991
992 return 1;
993}
994
995static int c_can_handle_bus_err(struct net_device *dev,
996 enum c_can_lec_type lec_type)
997{
998 struct c_can_priv *priv = netdev_priv(dev);
999 struct net_device_stats *stats = &dev->stats;
1000 struct can_frame *cf;
1001 struct sk_buff *skb;
1002
1003 /*
1004 * early exit if no lec update or no error.
1005 * no lec update means that no CAN bus event has been detected
1006 * since CPU wrote 0x7 value to status reg.
1007 */
1008 if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
1009 return 0;
1010
1011 if (!(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
1012 return 0;
1013
1014 /* common for all type of bus errors */
1015 priv->can.can_stats.bus_error++;
1016 stats->rx_errors++;
1017
1018 /* propagate the error condition to the CAN stack */
1019 skb = alloc_can_err_skb(dev, &cf);
1020 if (unlikely(!skb))
1021 return 0;
1022
1023 /*
1024 * check for 'last error code' which tells us the
1025 * type of the last error to occur on the CAN bus
1026 */
1027 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
1028
1029 switch (lec_type) {
1030 case LEC_STUFF_ERROR:
1031 netdev_dbg(dev, "stuff error\n");
1032 cf->data[2] |= CAN_ERR_PROT_STUFF;
1033 break;
1034 case LEC_FORM_ERROR:
1035 netdev_dbg(dev, "form error\n");
1036 cf->data[2] |= CAN_ERR_PROT_FORM;
1037 break;
1038 case LEC_ACK_ERROR:
1039 netdev_dbg(dev, "ack error\n");
1040 cf->data[3] = CAN_ERR_PROT_LOC_ACK;
1041 break;
1042 case LEC_BIT1_ERROR:
1043 netdev_dbg(dev, "bit1 error\n");
1044 cf->data[2] |= CAN_ERR_PROT_BIT1;
1045 break;
1046 case LEC_BIT0_ERROR:
1047 netdev_dbg(dev, "bit0 error\n");
1048 cf->data[2] |= CAN_ERR_PROT_BIT0;
1049 break;
1050 case LEC_CRC_ERROR:
1051 netdev_dbg(dev, "CRC error\n");
1052 cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
1053 break;
1054 default:
1055 break;
1056 }
1057
1058 stats->rx_packets++;
1059 stats->rx_bytes += cf->can_dlc;
1060 netif_receive_skb(skb);
1061 return 1;
1062}
1063
1064static int c_can_poll(struct napi_struct *napi, int quota)
1065{
1066 struct net_device *dev = napi->dev;
1067 struct c_can_priv *priv = netdev_priv(dev);
1068 u16 curr, last = priv->last_status;
1069 int work_done = 0;
1070
1071 /* Only read the status register if a status interrupt was pending */
1072 if (atomic_xchg(&priv->sie_pending, 0)) {
1073 priv->last_status = curr = priv->read_reg(priv, C_CAN_STS_REG);
1074 /* Ack status on C_CAN. D_CAN is self clearing */
1075 if (priv->type != BOSCH_D_CAN)
1076 priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED);
1077 } else {
1078 /* no change detected ... */
1079 curr = last;
1080 }
1081
1082 /* handle state changes */
1083 if ((curr & STATUS_EWARN) && (!(last & STATUS_EWARN))) {
1084 netdev_dbg(dev, "entered error warning state\n");
1085 work_done += c_can_handle_state_change(dev, C_CAN_ERROR_WARNING);
1086 }
1087
1088 if ((curr & STATUS_EPASS) && (!(last & STATUS_EPASS))) {
1089 netdev_dbg(dev, "entered error passive state\n");
1090 work_done += c_can_handle_state_change(dev, C_CAN_ERROR_PASSIVE);
1091 }
1092
1093 if ((curr & STATUS_BOFF) && (!(last & STATUS_BOFF))) {
1094 netdev_dbg(dev, "entered bus off state\n");
1095 work_done += c_can_handle_state_change(dev, C_CAN_BUS_OFF);
1096 goto end;
1097 }
1098
1099 /* handle bus recovery events */
1100 if ((!(curr & STATUS_BOFF)) && (last & STATUS_BOFF)) {
1101 netdev_dbg(dev, "left bus off state\n");
1102 work_done += c_can_handle_state_change(dev, C_CAN_ERROR_PASSIVE);
1103 }
1104
1105 if ((!(curr & STATUS_EPASS)) && (last & STATUS_EPASS)) {
1106 netdev_dbg(dev, "left error passive state\n");
1107 work_done += c_can_handle_state_change(dev, C_CAN_ERROR_WARNING);
1108 }
1109
1110 if ((!(curr & STATUS_EWARN)) && (last & STATUS_EWARN)) {
1111 netdev_dbg(dev, "left error warning state\n");
1112 work_done += c_can_handle_state_change(dev, C_CAN_NO_ERROR);
1113 }
1114
1115 /* handle lec errors on the bus */
1116 work_done += c_can_handle_bus_err(dev, curr & LEC_MASK);
1117
1118 /* Handle Tx/Rx events. We do this unconditionally */
1119 work_done += c_can_do_rx_poll(dev, (quota - work_done));
1120 c_can_do_tx(dev);
1121
1122end:
1123 if (work_done < quota) {
1124 napi_complete_done(napi, work_done);
1125 /* enable all IRQs if we are not in bus off state */
1126 if (priv->can.state != CAN_STATE_BUS_OFF)
1127 c_can_irq_control(priv, true);
1128 }
1129
1130 return work_done;
1131}
1132
1133static irqreturn_t c_can_isr(int irq, void *dev_id)
1134{
1135 struct net_device *dev = (struct net_device *)dev_id;
1136 struct c_can_priv *priv = netdev_priv(dev);
1137 int reg_int;
1138
1139 reg_int = priv->read_reg(priv, C_CAN_INT_REG);
1140 if (!reg_int)
1141 return IRQ_NONE;
1142
1143 /* save for later use */
1144 if (reg_int & INT_STS_PENDING)
1145 atomic_set(&priv->sie_pending, 1);
1146
1147 /* disable all interrupts and schedule the NAPI */
1148 c_can_irq_control(priv, false);
1149 napi_schedule(&priv->napi);
1150
1151 return IRQ_HANDLED;
1152}
1153
1154static int c_can_open(struct net_device *dev)
1155{
1156 int err;
1157 struct c_can_priv *priv = netdev_priv(dev);
1158
1159 c_can_pm_runtime_get_sync(priv);
1160 c_can_reset_ram(priv, true);
1161
1162 /* open the can device */
1163 err = open_candev(dev);
1164 if (err) {
1165 netdev_err(dev, "failed to open can device\n");
1166 goto exit_open_fail;
1167 }
1168
1169 /* register interrupt handler */
1170 err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name,
1171 dev);
1172 if (err < 0) {
1173 netdev_err(dev, "failed to request interrupt\n");
1174 goto exit_irq_fail;
1175 }
1176
1177 /* start the c_can controller */
1178 err = c_can_start(dev);
1179 if (err)
1180 goto exit_start_fail;
1181
1182 can_led_event(dev, CAN_LED_EVENT_OPEN);
1183
1184 napi_enable(&priv->napi);
1185 /* enable status change, error and module interrupts */
1186 c_can_irq_control(priv, true);
1187 netif_start_queue(dev);
1188
1189 return 0;
1190
1191exit_start_fail:
1192 free_irq(dev->irq, dev);
1193exit_irq_fail:
1194 close_candev(dev);
1195exit_open_fail:
1196 c_can_reset_ram(priv, false);
1197 c_can_pm_runtime_put_sync(priv);
1198 return err;
1199}
1200
1201static int c_can_close(struct net_device *dev)
1202{
1203 struct c_can_priv *priv = netdev_priv(dev);
1204
1205 netif_stop_queue(dev);
1206 napi_disable(&priv->napi);
1207 c_can_stop(dev);
1208 free_irq(dev->irq, dev);
1209 close_candev(dev);
1210
1211 c_can_reset_ram(priv, false);
1212 c_can_pm_runtime_put_sync(priv);
1213
1214 can_led_event(dev, CAN_LED_EVENT_STOP);
1215
1216 return 0;
1217}
1218
1219struct net_device *alloc_c_can_dev(void)
1220{
1221 struct net_device *dev;
1222 struct c_can_priv *priv;
1223
1224 dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
1225 if (!dev)
1226 return NULL;
1227
1228 priv = netdev_priv(dev);
1229 netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
1230
1231 priv->dev = dev;
1232 priv->can.bittiming_const = &c_can_bittiming_const;
1233 priv->can.do_set_mode = c_can_set_mode;
1234 priv->can.do_get_berr_counter = c_can_get_berr_counter;
1235 priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
1236 CAN_CTRLMODE_LISTENONLY |
1237 CAN_CTRLMODE_BERR_REPORTING;
1238
1239 return dev;
1240}
1241EXPORT_SYMBOL_GPL(alloc_c_can_dev);
1242
1243#ifdef CONFIG_PM
1244int c_can_power_down(struct net_device *dev)
1245{
1246 u32 val;
1247 unsigned long time_out;
1248 struct c_can_priv *priv = netdev_priv(dev);
1249
1250 if (!(dev->flags & IFF_UP))
1251 return 0;
1252
1253 WARN_ON(priv->type != BOSCH_D_CAN);
1254
1255 /* set PDR value so the device goes to power down mode */
1256 val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
1257 val |= CONTROL_EX_PDR;
1258 priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
1259
1260 /* Wait for the PDA bit to get set */
1261 time_out = jiffies + msecs_to_jiffies(INIT_WAIT_MS);
1262 while (!(priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
1263 time_after(time_out, jiffies))
1264 cpu_relax();
1265
1266 if (time_after(jiffies, time_out))
1267 return -ETIMEDOUT;
1268
1269 c_can_stop(dev);
1270
1271 c_can_reset_ram(priv, false);
1272 c_can_pm_runtime_put_sync(priv);
1273
1274 return 0;
1275}
1276EXPORT_SYMBOL_GPL(c_can_power_down);
1277
1278int c_can_power_up(struct net_device *dev)
1279{
1280 u32 val;
1281 unsigned long time_out;
1282 struct c_can_priv *priv = netdev_priv(dev);
1283 int ret;
1284
1285 if (!(dev->flags & IFF_UP))
1286 return 0;
1287
1288 WARN_ON(priv->type != BOSCH_D_CAN);
1289
1290 c_can_pm_runtime_get_sync(priv);
1291 c_can_reset_ram(priv, true);
1292
1293 /* Clear PDR and INIT bits */
1294 val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
1295 val &= ~CONTROL_EX_PDR;
1296 priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
1297 val = priv->read_reg(priv, C_CAN_CTRL_REG);
1298 val &= ~CONTROL_INIT;
1299 priv->write_reg(priv, C_CAN_CTRL_REG, val);
1300
1301 /* Wait for the PDA bit to get clear */
1302 time_out = jiffies + msecs_to_jiffies(INIT_WAIT_MS);
1303 while ((priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
1304 time_after(time_out, jiffies))
1305 cpu_relax();
1306
1307 if (time_after(jiffies, time_out))
1308 return -ETIMEDOUT;
1309
1310 ret = c_can_start(dev);
1311 if (!ret)
1312 c_can_irq_control(priv, true);
1313
1314 return ret;
1315}
1316EXPORT_SYMBOL_GPL(c_can_power_up);
1317#endif
1318
1319void free_c_can_dev(struct net_device *dev)
1320{
1321 struct c_can_priv *priv = netdev_priv(dev);
1322
1323 netif_napi_del(&priv->napi);
1324 free_candev(dev);
1325}
1326EXPORT_SYMBOL_GPL(free_c_can_dev);
1327
1328static const struct net_device_ops c_can_netdev_ops = {
1329 .ndo_open = c_can_open,
1330 .ndo_stop = c_can_close,
1331 .ndo_start_xmit = c_can_start_xmit,
1332 .ndo_change_mtu = can_change_mtu,
1333};
1334
1335int register_c_can_dev(struct net_device *dev)
1336{
1337 struct c_can_priv *priv = netdev_priv(dev);
1338 int err;
1339
1340 /* Deactivate pins to prevent DRA7 DCAN IP from being
1341 * stuck in transition when module is disabled.
1342 * Pins are activated in c_can_start() and deactivated
1343 * in c_can_stop()
1344 */
1345 pinctrl_pm_select_sleep_state(dev->dev.parent);
1346
1347 c_can_pm_runtime_enable(priv);
1348
1349 dev->flags |= IFF_ECHO; /* we support local echo */
1350 dev->netdev_ops = &c_can_netdev_ops;
1351
1352 err = register_candev(dev);
1353 if (err)
1354 c_can_pm_runtime_disable(priv);
1355 else
1356 devm_can_led_init(dev);
1357
1358 return err;
1359}
1360EXPORT_SYMBOL_GPL(register_c_can_dev);
1361
1362void unregister_c_can_dev(struct net_device *dev)
1363{
1364 struct c_can_priv *priv = netdev_priv(dev);
1365
1366 unregister_candev(dev);
1367
1368 c_can_pm_runtime_disable(priv);
1369}
1370EXPORT_SYMBOL_GPL(unregister_c_can_dev);
1371
1372MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
1373MODULE_LICENSE("GPL v2");
1374MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");
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 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 package, 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))) {
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 }
710 }
711
712 /* restart queue if wrap-up or if queue stalled on last pkt */
713 if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
714 ((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0))
715 netif_wake_queue(dev);
716}
717
718/*
719 * theory of operation:
720 *
721 * c_can core saves a received CAN message into the first free message
722 * object it finds free (starting with the lowest). Bits NEWDAT and
723 * INTPND are set for this message object indicating that a new message
724 * has arrived. To work-around this issue, we keep two groups of message
725 * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT.
726 *
727 * To ensure in-order frame reception we use the following
728 * approach while re-activating a message object to receive further
729 * frames:
730 * - if the current message object number is lower than
731 * C_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing
732 * the INTPND bit.
733 * - if the current message object number is equal to
734 * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower
735 * receive message objects.
736 * - if the current message object number is greater than
737 * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of
738 * only this message object.
739 */
740static int c_can_do_rx_poll(struct net_device *dev, int quota)
741{
742 u32 num_rx_pkts = 0;
743 unsigned int msg_obj, msg_ctrl_save;
744 struct c_can_priv *priv = netdev_priv(dev);
745 u32 val = c_can_read_reg32(priv, &priv->regs->intpnd1);
746
747 for (msg_obj = C_CAN_MSG_OBJ_RX_FIRST;
748 msg_obj <= C_CAN_MSG_OBJ_RX_LAST && quota > 0;
749 val = c_can_read_reg32(priv, &priv->regs->intpnd1),
750 msg_obj++) {
751 /*
752 * as interrupt pending register's bit n-1 corresponds to
753 * message object n, we need to handle the same properly.
754 */
755 if (val & (1 << (msg_obj - 1))) {
756 c_can_object_get(dev, 0, msg_obj, IF_COMM_ALL &
757 ~IF_COMM_TXRQST);
758 msg_ctrl_save = priv->read_reg(priv,
759 &priv->regs->ifregs[0].msg_cntrl);
760
761 if (msg_ctrl_save & IF_MCONT_EOB)
762 return num_rx_pkts;
763
764 if (msg_ctrl_save & IF_MCONT_MSGLST) {
765 c_can_handle_lost_msg_obj(dev, 0, msg_obj);
766 num_rx_pkts++;
767 quota--;
768 continue;
769 }
770
771 if (!(msg_ctrl_save & IF_MCONT_NEWDAT))
772 continue;
773
774 /* read the data from the message object */
775 c_can_read_msg_object(dev, 0, msg_ctrl_save);
776
777 if (msg_obj < C_CAN_MSG_RX_LOW_LAST)
778 c_can_mark_rx_msg_obj(dev, 0,
779 msg_ctrl_save, msg_obj);
780 else if (msg_obj > C_CAN_MSG_RX_LOW_LAST)
781 /* activate this msg obj */
782 c_can_activate_rx_msg_obj(dev, 0,
783 msg_ctrl_save, msg_obj);
784 else if (msg_obj == C_CAN_MSG_RX_LOW_LAST)
785 /* activate all lower message objects */
786 c_can_activate_all_lower_rx_msg_obj(dev,
787 0, msg_ctrl_save);
788
789 num_rx_pkts++;
790 quota--;
791 }
792 }
793
794 return num_rx_pkts;
795}
796
797static inline int c_can_has_and_handle_berr(struct c_can_priv *priv)
798{
799 return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
800 (priv->current_status & LEC_UNUSED);
801}
802
803static int c_can_handle_state_change(struct net_device *dev,
804 enum c_can_bus_error_types error_type)
805{
806 unsigned int reg_err_counter;
807 unsigned int rx_err_passive;
808 struct c_can_priv *priv = netdev_priv(dev);
809 struct net_device_stats *stats = &dev->stats;
810 struct can_frame *cf;
811 struct sk_buff *skb;
812 struct can_berr_counter bec;
813
814 /* propagate the error condition to the CAN stack */
815 skb = alloc_can_err_skb(dev, &cf);
816 if (unlikely(!skb))
817 return 0;
818
819 c_can_get_berr_counter(dev, &bec);
820 reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt);
821 rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >>
822 ERR_CNT_RP_SHIFT;
823
824 switch (error_type) {
825 case C_CAN_ERROR_WARNING:
826 /* error warning state */
827 priv->can.can_stats.error_warning++;
828 priv->can.state = CAN_STATE_ERROR_WARNING;
829 cf->can_id |= CAN_ERR_CRTL;
830 cf->data[1] = (bec.txerr > bec.rxerr) ?
831 CAN_ERR_CRTL_TX_WARNING :
832 CAN_ERR_CRTL_RX_WARNING;
833 cf->data[6] = bec.txerr;
834 cf->data[7] = bec.rxerr;
835
836 break;
837 case C_CAN_ERROR_PASSIVE:
838 /* error passive state */
839 priv->can.can_stats.error_passive++;
840 priv->can.state = CAN_STATE_ERROR_PASSIVE;
841 cf->can_id |= CAN_ERR_CRTL;
842 if (rx_err_passive)
843 cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
844 if (bec.txerr > 127)
845 cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
846
847 cf->data[6] = bec.txerr;
848 cf->data[7] = bec.rxerr;
849 break;
850 case C_CAN_BUS_OFF:
851 /* bus-off state */
852 priv->can.state = CAN_STATE_BUS_OFF;
853 cf->can_id |= CAN_ERR_BUSOFF;
854 /*
855 * disable all interrupts in bus-off mode to ensure that
856 * the CPU is not hogged down
857 */
858 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
859 can_bus_off(dev);
860 break;
861 default:
862 break;
863 }
864
865 netif_receive_skb(skb);
866 stats->rx_packets++;
867 stats->rx_bytes += cf->can_dlc;
868
869 return 1;
870}
871
872static int c_can_handle_bus_err(struct net_device *dev,
873 enum c_can_lec_type lec_type)
874{
875 struct c_can_priv *priv = netdev_priv(dev);
876 struct net_device_stats *stats = &dev->stats;
877 struct can_frame *cf;
878 struct sk_buff *skb;
879
880 /*
881 * early exit if no lec update or no error.
882 * no lec update means that no CAN bus event has been detected
883 * since CPU wrote 0x7 value to status reg.
884 */
885 if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
886 return 0;
887
888 /* propagate the error condition to the CAN stack */
889 skb = alloc_can_err_skb(dev, &cf);
890 if (unlikely(!skb))
891 return 0;
892
893 /*
894 * check for 'last error code' which tells us the
895 * type of the last error to occur on the CAN bus
896 */
897
898 /* common for all type of bus errors */
899 priv->can.can_stats.bus_error++;
900 stats->rx_errors++;
901 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
902 cf->data[2] |= CAN_ERR_PROT_UNSPEC;
903
904 switch (lec_type) {
905 case LEC_STUFF_ERROR:
906 netdev_dbg(dev, "stuff error\n");
907 cf->data[2] |= CAN_ERR_PROT_STUFF;
908 break;
909 case LEC_FORM_ERROR:
910 netdev_dbg(dev, "form error\n");
911 cf->data[2] |= CAN_ERR_PROT_FORM;
912 break;
913 case LEC_ACK_ERROR:
914 netdev_dbg(dev, "ack error\n");
915 cf->data[2] |= (CAN_ERR_PROT_LOC_ACK |
916 CAN_ERR_PROT_LOC_ACK_DEL);
917 break;
918 case LEC_BIT1_ERROR:
919 netdev_dbg(dev, "bit1 error\n");
920 cf->data[2] |= CAN_ERR_PROT_BIT1;
921 break;
922 case LEC_BIT0_ERROR:
923 netdev_dbg(dev, "bit0 error\n");
924 cf->data[2] |= CAN_ERR_PROT_BIT0;
925 break;
926 case LEC_CRC_ERROR:
927 netdev_dbg(dev, "CRC error\n");
928 cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
929 CAN_ERR_PROT_LOC_CRC_DEL);
930 break;
931 default:
932 break;
933 }
934
935 /* set a `lec` value so that we can check for updates later */
936 priv->write_reg(priv, &priv->regs->status, LEC_UNUSED);
937
938 netif_receive_skb(skb);
939 stats->rx_packets++;
940 stats->rx_bytes += cf->can_dlc;
941
942 return 1;
943}
944
945static int c_can_poll(struct napi_struct *napi, int quota)
946{
947 u16 irqstatus;
948 int lec_type = 0;
949 int work_done = 0;
950 struct net_device *dev = napi->dev;
951 struct c_can_priv *priv = netdev_priv(dev);
952
953 irqstatus = priv->read_reg(priv, &priv->regs->interrupt);
954 if (!irqstatus)
955 goto end;
956
957 /* status events have the highest priority */
958 if (irqstatus == STATUS_INTERRUPT) {
959 priv->current_status = priv->read_reg(priv,
960 &priv->regs->status);
961
962 /* handle Tx/Rx events */
963 if (priv->current_status & STATUS_TXOK)
964 priv->write_reg(priv, &priv->regs->status,
965 priv->current_status & ~STATUS_TXOK);
966
967 if (priv->current_status & STATUS_RXOK)
968 priv->write_reg(priv, &priv->regs->status,
969 priv->current_status & ~STATUS_RXOK);
970
971 /* handle state changes */
972 if ((priv->current_status & STATUS_EWARN) &&
973 (!(priv->last_status & STATUS_EWARN))) {
974 netdev_dbg(dev, "entered error warning state\n");
975 work_done += c_can_handle_state_change(dev,
976 C_CAN_ERROR_WARNING);
977 }
978 if ((priv->current_status & STATUS_EPASS) &&
979 (!(priv->last_status & STATUS_EPASS))) {
980 netdev_dbg(dev, "entered error passive state\n");
981 work_done += c_can_handle_state_change(dev,
982 C_CAN_ERROR_PASSIVE);
983 }
984 if ((priv->current_status & STATUS_BOFF) &&
985 (!(priv->last_status & STATUS_BOFF))) {
986 netdev_dbg(dev, "entered bus off state\n");
987 work_done += c_can_handle_state_change(dev,
988 C_CAN_BUS_OFF);
989 }
990
991 /* handle bus recovery events */
992 if ((!(priv->current_status & STATUS_BOFF)) &&
993 (priv->last_status & STATUS_BOFF)) {
994 netdev_dbg(dev, "left bus off state\n");
995 priv->can.state = CAN_STATE_ERROR_ACTIVE;
996 }
997 if ((!(priv->current_status & STATUS_EPASS)) &&
998 (priv->last_status & STATUS_EPASS)) {
999 netdev_dbg(dev, "left error passive state\n");
1000 priv->can.state = CAN_STATE_ERROR_ACTIVE;
1001 }
1002
1003 priv->last_status = priv->current_status;
1004
1005 /* handle lec errors on the bus */
1006 lec_type = c_can_has_and_handle_berr(priv);
1007 if (lec_type)
1008 work_done += c_can_handle_bus_err(dev, lec_type);
1009 } else if ((irqstatus >= C_CAN_MSG_OBJ_RX_FIRST) &&
1010 (irqstatus <= C_CAN_MSG_OBJ_RX_LAST)) {
1011 /* handle events corresponding to receive message objects */
1012 work_done += c_can_do_rx_poll(dev, (quota - work_done));
1013 } else if ((irqstatus >= C_CAN_MSG_OBJ_TX_FIRST) &&
1014 (irqstatus <= C_CAN_MSG_OBJ_TX_LAST)) {
1015 /* handle events corresponding to transmit message objects */
1016 c_can_do_tx(dev);
1017 }
1018
1019end:
1020 if (work_done < quota) {
1021 napi_complete(napi);
1022 /* enable all IRQs */
1023 c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
1024 }
1025
1026 return work_done;
1027}
1028
1029static irqreturn_t c_can_isr(int irq, void *dev_id)
1030{
1031 u16 irqstatus;
1032 struct net_device *dev = (struct net_device *)dev_id;
1033 struct c_can_priv *priv = netdev_priv(dev);
1034
1035 irqstatus = priv->read_reg(priv, &priv->regs->interrupt);
1036 if (!irqstatus)
1037 return IRQ_NONE;
1038
1039 /* disable all interrupts and schedule the NAPI */
1040 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
1041 napi_schedule(&priv->napi);
1042
1043 return IRQ_HANDLED;
1044}
1045
1046static int c_can_open(struct net_device *dev)
1047{
1048 int err;
1049 struct c_can_priv *priv = netdev_priv(dev);
1050
1051 /* open the can device */
1052 err = open_candev(dev);
1053 if (err) {
1054 netdev_err(dev, "failed to open can device\n");
1055 return err;
1056 }
1057
1058 /* register interrupt handler */
1059 err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name,
1060 dev);
1061 if (err < 0) {
1062 netdev_err(dev, "failed to request interrupt\n");
1063 goto exit_irq_fail;
1064 }
1065
1066 /* start the c_can controller */
1067 c_can_start(dev);
1068
1069 napi_enable(&priv->napi);
1070 netif_start_queue(dev);
1071
1072 return 0;
1073
1074exit_irq_fail:
1075 close_candev(dev);
1076 return err;
1077}
1078
1079static int c_can_close(struct net_device *dev)
1080{
1081 struct c_can_priv *priv = netdev_priv(dev);
1082
1083 netif_stop_queue(dev);
1084 napi_disable(&priv->napi);
1085 c_can_stop(dev);
1086 free_irq(dev->irq, dev);
1087 close_candev(dev);
1088
1089 return 0;
1090}
1091
1092struct net_device *alloc_c_can_dev(void)
1093{
1094 struct net_device *dev;
1095 struct c_can_priv *priv;
1096
1097 dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
1098 if (!dev)
1099 return NULL;
1100
1101 priv = netdev_priv(dev);
1102 netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
1103
1104 priv->dev = dev;
1105 priv->can.bittiming_const = &c_can_bittiming_const;
1106 priv->can.do_set_mode = c_can_set_mode;
1107 priv->can.do_get_berr_counter = c_can_get_berr_counter;
1108 priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
1109 CAN_CTRLMODE_LISTENONLY |
1110 CAN_CTRLMODE_BERR_REPORTING;
1111
1112 return dev;
1113}
1114EXPORT_SYMBOL_GPL(alloc_c_can_dev);
1115
1116void free_c_can_dev(struct net_device *dev)
1117{
1118 free_candev(dev);
1119}
1120EXPORT_SYMBOL_GPL(free_c_can_dev);
1121
1122static const struct net_device_ops c_can_netdev_ops = {
1123 .ndo_open = c_can_open,
1124 .ndo_stop = c_can_close,
1125 .ndo_start_xmit = c_can_start_xmit,
1126};
1127
1128int register_c_can_dev(struct net_device *dev)
1129{
1130 dev->flags |= IFF_ECHO; /* we support local echo */
1131 dev->netdev_ops = &c_can_netdev_ops;
1132
1133 return register_candev(dev);
1134}
1135EXPORT_SYMBOL_GPL(register_c_can_dev);
1136
1137void unregister_c_can_dev(struct net_device *dev)
1138{
1139 struct c_can_priv *priv = netdev_priv(dev);
1140
1141 /* disable all interrupts */
1142 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
1143
1144 unregister_candev(dev);
1145}
1146EXPORT_SYMBOL_GPL(unregister_c_can_dev);
1147
1148MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
1149MODULE_LICENSE("GPL v2");
1150MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");