xref: /linux/drivers/net/can/ctucanfd/ctucanfd_base.c (revision 93fbff1197474d7b65e598c6f48fa82a5c334539)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3  *
4  * CTU CAN FD IP Core
5  *
6  * Copyright (C) 2015-2018 Ondrej Ille <ondrej.ille@gmail.com> FEE CTU
7  * Copyright (C) 2018-2021 Ondrej Ille <ondrej.ille@gmail.com> self-funded
8  * Copyright (C) 2018-2019 Martin Jerabek <martin.jerabek01@gmail.com> FEE CTU
9  * Copyright (C) 2018-2022 Pavel Pisa <pisa@cmp.felk.cvut.cz> FEE CTU/self-funded
10  *
11  * Project advisors:
12  *     Jiri Novak <jnovak@fel.cvut.cz>
13  *     Pavel Pisa <pisa@cmp.felk.cvut.cz>
14  *
15  * Department of Measurement         (http://meas.fel.cvut.cz/)
16  * Faculty of Electrical Engineering (http://www.fel.cvut.cz)
17  * Czech Technical University        (http://www.cvut.cz/)
18  ******************************************************************************/
19 
20 #include <linux/clk.h>
21 #include <linux/errno.h>
22 #include <linux/ethtool.h>
23 #include <linux/init.h>
24 #include <linux/bitfield.h>
25 #include <linux/interrupt.h>
26 #include <linux/io.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/skbuff.h>
30 #include <linux/string.h>
31 #include <linux/types.h>
32 #include <linux/can/error.h>
33 #include <linux/pm_runtime.h>
34 
35 #include "ctucanfd.h"
36 #include "ctucanfd_kregs.h"
37 #include "ctucanfd_kframe.h"
38 
39 #ifdef DEBUG
40 #define  ctucan_netdev_dbg(ndev, args...) \
41 		netdev_dbg(ndev, args)
42 #else
43 #define ctucan_netdev_dbg(...) do { } while (0)
44 #endif
45 
46 #define CTUCANFD_ID 0xCAFD
47 
48 /* TX buffer rotation:
49  * - when a buffer transitions to empty state, rotate order and priorities
50  * - if more buffers seem to transition at the same time, rotate by the number of buffers
51  * - it may be assumed that buffers transition to empty state in FIFO order (because we manage
52  *   priorities that way)
53  * - at frame filling, do not rotate anything, just increment buffer modulo counter
54  */
55 
56 #define CTUCANFD_FLAG_RX_FFW_BUFFERED	1
57 
58 #define CTUCAN_STATE_TO_TEXT_ENTRY(st) \
59 		[st] = #st
60 
61 enum ctucan_txtb_status {
62 	TXT_NOT_EXIST       = 0x0,
63 	TXT_RDY             = 0x1,
64 	TXT_TRAN            = 0x2,
65 	TXT_ABTP            = 0x3,
66 	TXT_TOK             = 0x4,
67 	TXT_ERR             = 0x6,
68 	TXT_ABT             = 0x7,
69 	TXT_ETY             = 0x8,
70 };
71 
72 enum ctucan_txtb_command {
73 	TXT_CMD_SET_EMPTY   = 0x01,
74 	TXT_CMD_SET_READY   = 0x02,
75 	TXT_CMD_SET_ABORT   = 0x04
76 };
77 
78 static const struct can_bittiming_const ctu_can_fd_bit_timing_max = {
79 	.name = "ctu_can_fd",
80 	.tseg1_min = 2,
81 	.tseg1_max = 190,
82 	.tseg2_min = 1,
83 	.tseg2_max = 63,
84 	.sjw_max = 31,
85 	.brp_min = 1,
86 	.brp_max = 8,
87 	.brp_inc = 1,
88 };
89 
90 static const struct can_bittiming_const ctu_can_fd_bit_timing_data_max = {
91 	.name = "ctu_can_fd",
92 	.tseg1_min = 2,
93 	.tseg1_max = 94,
94 	.tseg2_min = 1,
95 	.tseg2_max = 31,
96 	.sjw_max = 31,
97 	.brp_min = 1,
98 	.brp_max = 2,
99 	.brp_inc = 1,
100 };
101 
102 static const char * const ctucan_state_strings[CAN_STATE_MAX] = {
103 	CTUCAN_STATE_TO_TEXT_ENTRY(CAN_STATE_ERROR_ACTIVE),
104 	CTUCAN_STATE_TO_TEXT_ENTRY(CAN_STATE_ERROR_WARNING),
105 	CTUCAN_STATE_TO_TEXT_ENTRY(CAN_STATE_ERROR_PASSIVE),
106 	CTUCAN_STATE_TO_TEXT_ENTRY(CAN_STATE_BUS_OFF),
107 	CTUCAN_STATE_TO_TEXT_ENTRY(CAN_STATE_STOPPED),
108 	CTUCAN_STATE_TO_TEXT_ENTRY(CAN_STATE_SLEEPING)
109 };
110 
111 static void ctucan_write32_le(struct ctucan_priv *priv,
112 			      enum ctu_can_fd_can_registers reg, u32 val)
113 {
114 	iowrite32(val, priv->mem_base + reg);
115 }
116 
117 static void ctucan_write32_be(struct ctucan_priv *priv,
118 			      enum ctu_can_fd_can_registers reg, u32 val)
119 {
120 	iowrite32be(val, priv->mem_base + reg);
121 }
122 
123 static u32 ctucan_read32_le(struct ctucan_priv *priv,
124 			    enum ctu_can_fd_can_registers reg)
125 {
126 	return ioread32(priv->mem_base + reg);
127 }
128 
129 static u32 ctucan_read32_be(struct ctucan_priv *priv,
130 			    enum ctu_can_fd_can_registers reg)
131 {
132 	return ioread32be(priv->mem_base + reg);
133 }
134 
135 static void ctucan_write32(struct ctucan_priv *priv, enum ctu_can_fd_can_registers reg, u32 val)
136 {
137 	priv->write_reg(priv, reg, val);
138 }
139 
140 static u32 ctucan_read32(struct ctucan_priv *priv, enum ctu_can_fd_can_registers reg)
141 {
142 	return priv->read_reg(priv, reg);
143 }
144 
145 static void ctucan_write_txt_buf(struct ctucan_priv *priv, enum ctu_can_fd_can_registers buf_base,
146 				 u32 offset, u32 val)
147 {
148 	priv->write_reg(priv, buf_base + offset, val);
149 }
150 
151 #define CTU_CAN_FD_TXTNF(priv) (!!FIELD_GET(REG_STATUS_TXNF, ctucan_read32(priv, CTUCANFD_STATUS)))
152 #define CTU_CAN_FD_ENABLED(priv) (!!FIELD_GET(REG_MODE_ENA, ctucan_read32(priv, CTUCANFD_MODE)))
153 
154 /**
155  * ctucan_state_to_str() - Converts CAN controller state code to corresponding text
156  * @state:	CAN controller state code
157  *
158  * Return: Pointer to string representation of the error state
159  */
160 static const char *ctucan_state_to_str(enum can_state state)
161 {
162 	const char *txt = NULL;
163 
164 	if (state >= 0 && state < CAN_STATE_MAX)
165 		txt = ctucan_state_strings[state];
166 	return txt ? txt : "UNKNOWN";
167 }
168 
169 /**
170  * ctucan_reset() - Issues software reset request to CTU CAN FD
171  * @ndev:	Pointer to net_device structure
172  *
173  * Return: 0 for success, -%ETIMEDOUT if CAN controller does not leave reset
174  */
175 static int ctucan_reset(struct net_device *ndev)
176 {
177 	struct ctucan_priv *priv = netdev_priv(ndev);
178 	int i = 100;
179 
180 	ctucan_write32(priv, CTUCANFD_MODE, REG_MODE_RST);
181 	clear_bit(CTUCANFD_FLAG_RX_FFW_BUFFERED, &priv->drv_flags);
182 
183 	do {
184 		u16 device_id = FIELD_GET(REG_DEVICE_ID_DEVICE_ID,
185 					  ctucan_read32(priv, CTUCANFD_DEVICE_ID));
186 
187 		if (device_id == 0xCAFD)
188 			return 0;
189 		if (!i--) {
190 			netdev_warn(ndev, "device did not leave reset\n");
191 			return -ETIMEDOUT;
192 		}
193 		usleep_range(100, 200);
194 	} while (1);
195 }
196 
197 /**
198  * ctucan_set_btr() - Sets CAN bus bit timing in CTU CAN FD
199  * @ndev:	Pointer to net_device structure
200  * @bt:		Pointer to Bit timing structure
201  * @nominal:	True - Nominal bit timing, False - Data bit timing
202  *
203  * Return: 0 - OK, -%EPERM if controller is enabled
204  */
205 static int ctucan_set_btr(struct net_device *ndev, struct can_bittiming *bt, bool nominal)
206 {
207 	struct ctucan_priv *priv = netdev_priv(ndev);
208 	int max_ph1_len = 31;
209 	u32 btr = 0;
210 	u32 prop_seg = bt->prop_seg;
211 	u32 phase_seg1 = bt->phase_seg1;
212 
213 	if (CTU_CAN_FD_ENABLED(priv)) {
214 		netdev_err(ndev, "BUG! Cannot set bittiming - CAN is enabled\n");
215 		return -EPERM;
216 	}
217 
218 	if (nominal)
219 		max_ph1_len = 63;
220 
221 	/* The timing calculation functions have only constraints on tseg1, which is prop_seg +
222 	 * phase1_seg combined. tseg1 is then split in half and stored into prog_seg and phase_seg1.
223 	 * In CTU CAN FD, PROP is 6/7 bits wide but PH1 only 6/5, so we must re-distribute the
224 	 * values here.
225 	 */
226 	if (phase_seg1 > max_ph1_len) {
227 		prop_seg += phase_seg1 - max_ph1_len;
228 		phase_seg1 = max_ph1_len;
229 		bt->prop_seg = prop_seg;
230 		bt->phase_seg1 = phase_seg1;
231 	}
232 
233 	if (nominal) {
234 		btr = FIELD_PREP(REG_BTR_PROP, prop_seg);
235 		btr |= FIELD_PREP(REG_BTR_PH1, phase_seg1);
236 		btr |= FIELD_PREP(REG_BTR_PH2, bt->phase_seg2);
237 		btr |= FIELD_PREP(REG_BTR_BRP, bt->brp);
238 		btr |= FIELD_PREP(REG_BTR_SJW, bt->sjw);
239 
240 		ctucan_write32(priv, CTUCANFD_BTR, btr);
241 	} else {
242 		btr = FIELD_PREP(REG_BTR_FD_PROP_FD, prop_seg);
243 		btr |= FIELD_PREP(REG_BTR_FD_PH1_FD, phase_seg1);
244 		btr |= FIELD_PREP(REG_BTR_FD_PH2_FD, bt->phase_seg2);
245 		btr |= FIELD_PREP(REG_BTR_FD_BRP_FD, bt->brp);
246 		btr |= FIELD_PREP(REG_BTR_FD_SJW_FD, bt->sjw);
247 
248 		ctucan_write32(priv, CTUCANFD_BTR_FD, btr);
249 	}
250 
251 	return 0;
252 }
253 
254 /**
255  * ctucan_set_bittiming() - CAN set nominal bit timing routine
256  * @ndev:	Pointer to net_device structure
257  *
258  * Return: 0 on success, -%EPERM on error
259  */
260 static int ctucan_set_bittiming(struct net_device *ndev)
261 {
262 	struct ctucan_priv *priv = netdev_priv(ndev);
263 	struct can_bittiming *bt = &priv->can.bittiming;
264 
265 	/* Note that bt may be modified here */
266 	return ctucan_set_btr(ndev, bt, true);
267 }
268 
269 /**
270  * ctucan_set_data_bittiming() - CAN set data bit timing routine
271  * @ndev:	Pointer to net_device structure
272  *
273  * Return: 0 on success, -%EPERM on error
274  */
275 static int ctucan_set_data_bittiming(struct net_device *ndev)
276 {
277 	struct ctucan_priv *priv = netdev_priv(ndev);
278 	struct can_bittiming *dbt = &priv->can.data_bittiming;
279 
280 	/* Note that dbt may be modified here */
281 	return ctucan_set_btr(ndev, dbt, false);
282 }
283 
284 /**
285  * ctucan_set_secondary_sample_point() - Sets secondary sample point in CTU CAN FD
286  * @ndev:	Pointer to net_device structure
287  *
288  * Return: 0 on success, -%EPERM if controller is enabled
289  */
290 static int ctucan_set_secondary_sample_point(struct net_device *ndev)
291 {
292 	struct ctucan_priv *priv = netdev_priv(ndev);
293 	struct can_bittiming *dbt = &priv->can.data_bittiming;
294 	int ssp_offset = 0;
295 	u32 ssp_cfg = 0; /* No SSP by default */
296 
297 	if (CTU_CAN_FD_ENABLED(priv)) {
298 		netdev_err(ndev, "BUG! Cannot set SSP - CAN is enabled\n");
299 		return -EPERM;
300 	}
301 
302 	/* Use SSP for bit-rates above 1 Mbits/s */
303 	if (dbt->bitrate > 1000000) {
304 		/* Calculate SSP in minimal time quanta */
305 		ssp_offset = (priv->can.clock.freq / 1000) * dbt->sample_point / dbt->bitrate;
306 
307 		if (ssp_offset > 127) {
308 			netdev_warn(ndev, "SSP offset saturated to 127\n");
309 			ssp_offset = 127;
310 		}
311 
312 		ssp_cfg = FIELD_PREP(REG_TRV_DELAY_SSP_OFFSET, ssp_offset);
313 		ssp_cfg |= FIELD_PREP(REG_TRV_DELAY_SSP_SRC, 0x1);
314 	}
315 
316 	ctucan_write32(priv, CTUCANFD_TRV_DELAY, ssp_cfg);
317 
318 	return 0;
319 }
320 
321 /**
322  * ctucan_set_mode() - Sets CTU CAN FDs mode
323  * @priv:	Pointer to private data
324  * @mode:	Pointer to controller modes to be set
325  */
326 static void ctucan_set_mode(struct ctucan_priv *priv, const struct can_ctrlmode *mode)
327 {
328 	u32 mode_reg = ctucan_read32(priv, CTUCANFD_MODE);
329 
330 	mode_reg = (mode->flags & CAN_CTRLMODE_LOOPBACK) ?
331 			(mode_reg | REG_MODE_ILBP) :
332 			(mode_reg & ~REG_MODE_ILBP);
333 
334 	mode_reg = (mode->flags & CAN_CTRLMODE_LISTENONLY) ?
335 			(mode_reg | REG_MODE_BMM) :
336 			(mode_reg & ~REG_MODE_BMM);
337 
338 	mode_reg = (mode->flags & CAN_CTRLMODE_FD) ?
339 			(mode_reg | REG_MODE_FDE) :
340 			(mode_reg & ~REG_MODE_FDE);
341 
342 	mode_reg = (mode->flags & CAN_CTRLMODE_PRESUME_ACK) ?
343 			(mode_reg | REG_MODE_ACF) :
344 			(mode_reg & ~REG_MODE_ACF);
345 
346 	mode_reg = (mode->flags & CAN_CTRLMODE_FD_NON_ISO) ?
347 			(mode_reg | REG_MODE_NISOFD) :
348 			(mode_reg & ~REG_MODE_NISOFD);
349 
350 	/* One shot mode supported indirectly via Retransmit limit */
351 	mode_reg &= ~FIELD_PREP(REG_MODE_RTRTH, 0xF);
352 	mode_reg = (mode->flags & CAN_CTRLMODE_ONE_SHOT) ?
353 			(mode_reg | REG_MODE_RTRLE) :
354 			(mode_reg & ~REG_MODE_RTRLE);
355 
356 	/* Some bits fixed:
357 	 *   TSTM  - Off, User shall not be able to change REC/TEC by hand during operation
358 	 */
359 	mode_reg &= ~REG_MODE_TSTM;
360 
361 	ctucan_write32(priv, CTUCANFD_MODE, mode_reg);
362 }
363 
364 /**
365  * ctucan_chip_start() - This routine starts the driver
366  * @ndev:	Pointer to net_device structure
367  *
368  * Routine expects that chip is in reset state. It setups initial
369  * Tx buffers for FIFO priorities, sets bittiming, enables interrupts,
370  * switches core to operational mode and changes controller
371  * state to %CAN_STATE_STOPPED.
372  *
373  * Return: 0 on success and failure value on error
374  */
375 static int ctucan_chip_start(struct net_device *ndev)
376 {
377 	struct ctucan_priv *priv = netdev_priv(ndev);
378 	u32 int_ena, int_msk;
379 	u32 mode_reg;
380 	int err;
381 	struct can_ctrlmode mode;
382 
383 	priv->txb_prio = 0x01234567;
384 	priv->txb_head = 0;
385 	priv->txb_tail = 0;
386 	ctucan_write32(priv, CTUCANFD_TX_PRIORITY, priv->txb_prio);
387 
388 	/* Configure bit-rates and ssp */
389 	err = ctucan_set_bittiming(ndev);
390 	if (err < 0)
391 		return err;
392 
393 	err = ctucan_set_data_bittiming(ndev);
394 	if (err < 0)
395 		return err;
396 
397 	err = ctucan_set_secondary_sample_point(ndev);
398 	if (err < 0)
399 		return err;
400 
401 	/* Configure modes */
402 	mode.flags = priv->can.ctrlmode;
403 	mode.mask = 0xFFFFFFFF;
404 	ctucan_set_mode(priv, &mode);
405 
406 	/* Configure interrupts */
407 	int_ena = REG_INT_STAT_RBNEI |
408 		  REG_INT_STAT_TXBHCI |
409 		  REG_INT_STAT_EWLI |
410 		  REG_INT_STAT_FCSI;
411 
412 	/* Bus error reporting -> Allow Error/Arb.lost interrupts */
413 	if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) {
414 		int_ena |= REG_INT_STAT_ALI |
415 			   REG_INT_STAT_BEI;
416 	}
417 
418 	int_msk = ~int_ena; /* Mask all disabled interrupts */
419 
420 	/* It's after reset, so there is no need to clear anything */
421 	ctucan_write32(priv, CTUCANFD_INT_MASK_SET, int_msk);
422 	ctucan_write32(priv, CTUCANFD_INT_ENA_SET, int_ena);
423 
424 	/* Controller enters ERROR_ACTIVE on initial FCSI */
425 	priv->can.state = CAN_STATE_STOPPED;
426 
427 	/* Enable the controller */
428 	mode_reg = ctucan_read32(priv, CTUCANFD_MODE);
429 	mode_reg |= REG_MODE_ENA;
430 	ctucan_write32(priv, CTUCANFD_MODE, mode_reg);
431 
432 	return 0;
433 }
434 
435 /**
436  * ctucan_do_set_mode() - Sets mode of the driver
437  * @ndev:	Pointer to net_device structure
438  * @mode:	Tells the mode of the driver
439  *
440  * This check the drivers state and calls the corresponding modes to set.
441  *
442  * Return: 0 on success and failure value on error
443  */
444 static int ctucan_do_set_mode(struct net_device *ndev, enum can_mode mode)
445 {
446 	int ret;
447 
448 	switch (mode) {
449 	case CAN_MODE_START:
450 		ret = ctucan_reset(ndev);
451 		if (ret < 0)
452 			return ret;
453 		ret = ctucan_chip_start(ndev);
454 		if (ret < 0) {
455 			netdev_err(ndev, "ctucan_chip_start failed!\n");
456 			return ret;
457 		}
458 		netif_wake_queue(ndev);
459 		break;
460 	default:
461 		ret = -EOPNOTSUPP;
462 		break;
463 	}
464 
465 	return ret;
466 }
467 
468 /**
469  * ctucan_get_tx_status() - Gets status of TXT buffer
470  * @priv:	Pointer to private data
471  * @buf:	Buffer index (0-based)
472  *
473  * Return: Status of TXT buffer
474  */
475 static enum ctucan_txtb_status ctucan_get_tx_status(struct ctucan_priv *priv, u8 buf)
476 {
477 	u32 tx_status = ctucan_read32(priv, CTUCANFD_TX_STATUS);
478 	enum ctucan_txtb_status status = (tx_status >> (buf * 4)) & 0x7;
479 
480 	return status;
481 }
482 
483 /**
484  * ctucan_is_txt_buf_writable() - Checks if frame can be inserted to TXT Buffer
485  * @priv:	Pointer to private data
486  * @buf:	Buffer index (0-based)
487  *
488  * Return: True - Frame can be inserted to TXT Buffer, False - If attempted, frame will not be
489  *	   inserted to TXT Buffer
490  */
491 static bool ctucan_is_txt_buf_writable(struct ctucan_priv *priv, u8 buf)
492 {
493 	enum ctucan_txtb_status buf_status;
494 
495 	buf_status = ctucan_get_tx_status(priv, buf);
496 	if (buf_status == TXT_RDY || buf_status == TXT_TRAN || buf_status == TXT_ABTP)
497 		return false;
498 
499 	return true;
500 }
501 
502 /**
503  * ctucan_insert_frame() - Inserts frame to TXT buffer
504  * @priv:	Pointer to private data
505  * @cf:		Pointer to CAN frame to be inserted
506  * @buf:	TXT Buffer index to which frame is inserted (0-based)
507  * @isfdf:	True - CAN FD Frame, False - CAN 2.0 Frame
508  *
509  * Return: True - Frame inserted successfully
510  *	   False - Frame was not inserted due to one of:
511  *			1. TXT Buffer is not writable (it is in wrong state)
512  *			2. Invalid TXT buffer index
513  *			3. Invalid frame length
514  */
515 static bool ctucan_insert_frame(struct ctucan_priv *priv, const struct canfd_frame *cf, u8 buf,
516 				bool isfdf)
517 {
518 	u32 buf_base;
519 	u32 ffw = 0;
520 	u32 idw = 0;
521 	unsigned int i;
522 
523 	if (buf >= priv->ntxbufs)
524 		return false;
525 
526 	if (!ctucan_is_txt_buf_writable(priv, buf))
527 		return false;
528 
529 	if (cf->len > CANFD_MAX_DLEN)
530 		return false;
531 
532 	/* Prepare Frame format */
533 	if (cf->can_id & CAN_RTR_FLAG)
534 		ffw |= REG_FRAME_FORMAT_W_RTR;
535 
536 	if (cf->can_id & CAN_EFF_FLAG)
537 		ffw |= REG_FRAME_FORMAT_W_IDE;
538 
539 	if (isfdf) {
540 		ffw |= REG_FRAME_FORMAT_W_FDF;
541 		if (cf->flags & CANFD_BRS)
542 			ffw |= REG_FRAME_FORMAT_W_BRS;
543 	}
544 
545 	ffw |= FIELD_PREP(REG_FRAME_FORMAT_W_DLC, can_fd_len2dlc(cf->len));
546 
547 	/* Prepare identifier */
548 	if (cf->can_id & CAN_EFF_FLAG)
549 		idw = cf->can_id & CAN_EFF_MASK;
550 	else
551 		idw = FIELD_PREP(REG_IDENTIFIER_W_IDENTIFIER_BASE, cf->can_id & CAN_SFF_MASK);
552 
553 	/* Write ID, Frame format, Don't write timestamp -> Time triggered transmission disabled */
554 	buf_base = (buf + 1) * 0x100;
555 	ctucan_write_txt_buf(priv, buf_base, CTUCANFD_FRAME_FORMAT_W, ffw);
556 	ctucan_write_txt_buf(priv, buf_base, CTUCANFD_IDENTIFIER_W, idw);
557 
558 	/* Write Data payload */
559 	if (!(cf->can_id & CAN_RTR_FLAG)) {
560 		for (i = 0; i < cf->len; i += 4) {
561 			u32 data = le32_to_cpu(*(__le32 *)(cf->data + i));
562 
563 			ctucan_write_txt_buf(priv, buf_base, CTUCANFD_DATA_1_4_W + i, data);
564 		}
565 	}
566 
567 	return true;
568 }
569 
570 /**
571  * ctucan_give_txtb_cmd() - Applies command on TXT buffer
572  * @priv:	Pointer to private data
573  * @cmd:	Command to give
574  * @buf:	Buffer index (0-based)
575  */
576 static void ctucan_give_txtb_cmd(struct ctucan_priv *priv, enum ctucan_txtb_command cmd, u8 buf)
577 {
578 	u32 tx_cmd = cmd;
579 
580 	tx_cmd |= 1 << (buf + 8);
581 	ctucan_write32(priv, CTUCANFD_TX_COMMAND, tx_cmd);
582 }
583 
584 /**
585  * ctucan_start_xmit() - Starts the transmission
586  * @skb:	sk_buff pointer that contains data to be Txed
587  * @ndev:	Pointer to net_device structure
588  *
589  * Invoked from upper layers to initiate transmission. Uses the next available free TXT Buffer and
590  * populates its fields to start the transmission.
591  *
592  * Return: %NETDEV_TX_OK on success, %NETDEV_TX_BUSY when no free TXT buffer is available,
593  *         negative return values reserved for error cases
594  */
595 static netdev_tx_t ctucan_start_xmit(struct sk_buff *skb, struct net_device *ndev)
596 {
597 	struct ctucan_priv *priv = netdev_priv(ndev);
598 	struct canfd_frame *cf = (struct canfd_frame *)skb->data;
599 	u32 txtb_id;
600 	bool ok;
601 	unsigned long flags;
602 
603 	if (can_dropped_invalid_skb(ndev, skb))
604 		return NETDEV_TX_OK;
605 
606 	if (unlikely(!CTU_CAN_FD_TXTNF(priv))) {
607 		netif_stop_queue(ndev);
608 		netdev_err(ndev, "BUG!, no TXB free when queue awake!\n");
609 		return NETDEV_TX_BUSY;
610 	}
611 
612 	txtb_id = priv->txb_head % priv->ntxbufs;
613 	ctucan_netdev_dbg(ndev, "%s: using TXB#%u\n", __func__, txtb_id);
614 	ok = ctucan_insert_frame(priv, cf, txtb_id, can_is_canfd_skb(skb));
615 
616 	if (!ok) {
617 		netdev_err(ndev, "BUG! TXNF set but cannot insert frame into TXTB! HW Bug?");
618 		kfree_skb(skb);
619 		ndev->stats.tx_dropped++;
620 		return NETDEV_TX_OK;
621 	}
622 
623 	can_put_echo_skb(skb, ndev, txtb_id, 0);
624 
625 	spin_lock_irqsave(&priv->tx_lock, flags);
626 	ctucan_give_txtb_cmd(priv, TXT_CMD_SET_READY, txtb_id);
627 	priv->txb_head++;
628 
629 	/* Check if all TX buffers are full */
630 	if (!CTU_CAN_FD_TXTNF(priv))
631 		netif_stop_queue(ndev);
632 
633 	spin_unlock_irqrestore(&priv->tx_lock, flags);
634 
635 	return NETDEV_TX_OK;
636 }
637 
638 /**
639  * ctucan_read_rx_frame() - Reads frame from RX FIFO
640  * @priv:	Pointer to CTU CAN FD's private data
641  * @cf:		Pointer to CAN frame struct
642  * @ffw:	Previously read frame format word
643  *
644  * Note: Frame format word must be read separately and provided in 'ffw'.
645  */
646 static void ctucan_read_rx_frame(struct ctucan_priv *priv, struct canfd_frame *cf, u32 ffw)
647 {
648 	u32 idw;
649 	unsigned int i;
650 	unsigned int wc;
651 	unsigned int len;
652 
653 	idw = ctucan_read32(priv, CTUCANFD_RX_DATA);
654 	if (FIELD_GET(REG_FRAME_FORMAT_W_IDE, ffw))
655 		cf->can_id = (idw & CAN_EFF_MASK) | CAN_EFF_FLAG;
656 	else
657 		cf->can_id = (idw >> 18) & CAN_SFF_MASK;
658 
659 	/* BRS, ESI, RTR Flags */
660 	cf->flags = 0;
661 	if (FIELD_GET(REG_FRAME_FORMAT_W_FDF, ffw)) {
662 		if (FIELD_GET(REG_FRAME_FORMAT_W_BRS, ffw))
663 			cf->flags |= CANFD_BRS;
664 		if (FIELD_GET(REG_FRAME_FORMAT_W_ESI_RSV, ffw))
665 			cf->flags |= CANFD_ESI;
666 	} else if (FIELD_GET(REG_FRAME_FORMAT_W_RTR, ffw)) {
667 		cf->can_id |= CAN_RTR_FLAG;
668 	}
669 
670 	wc = FIELD_GET(REG_FRAME_FORMAT_W_RWCNT, ffw) - 3;
671 
672 	/* DLC */
673 	if (FIELD_GET(REG_FRAME_FORMAT_W_DLC, ffw) <= 8) {
674 		len = FIELD_GET(REG_FRAME_FORMAT_W_DLC, ffw);
675 	} else {
676 		if (FIELD_GET(REG_FRAME_FORMAT_W_FDF, ffw))
677 			len = wc << 2;
678 		else
679 			len = 8;
680 	}
681 	cf->len = len;
682 	if (unlikely(len > wc * 4))
683 		len = wc * 4;
684 
685 	/* Timestamp - Read and throw away */
686 	ctucan_read32(priv, CTUCANFD_RX_DATA);
687 	ctucan_read32(priv, CTUCANFD_RX_DATA);
688 
689 	/* Data */
690 	for (i = 0; i < len; i += 4) {
691 		u32 data = ctucan_read32(priv, CTUCANFD_RX_DATA);
692 		*(__le32 *)(cf->data + i) = cpu_to_le32(data);
693 	}
694 	while (unlikely(i < wc * 4)) {
695 		ctucan_read32(priv, CTUCANFD_RX_DATA);
696 		i += 4;
697 	}
698 }
699 
700 /**
701  * ctucan_rx() -  Called from CAN ISR to complete the received frame processing
702  * @ndev:	Pointer to net_device structure
703  *
704  * This function is invoked from the CAN isr(poll) to process the Rx frames. It does minimal
705  * processing and invokes "netif_receive_skb" to complete further processing.
706  * Return: 1 when frame is passed to the network layer, 0 when the first frame word is read but
707  *	   system is out of free SKBs temporally and left code to resolve SKB allocation later,
708  *         -%EAGAIN in a case of empty Rx FIFO.
709  */
710 static int ctucan_rx(struct net_device *ndev)
711 {
712 	struct ctucan_priv *priv = netdev_priv(ndev);
713 	struct net_device_stats *stats = &ndev->stats;
714 	struct canfd_frame *cf;
715 	struct sk_buff *skb;
716 	u32 ffw;
717 
718 	if (test_bit(CTUCANFD_FLAG_RX_FFW_BUFFERED, &priv->drv_flags)) {
719 		ffw = priv->rxfrm_first_word;
720 		clear_bit(CTUCANFD_FLAG_RX_FFW_BUFFERED, &priv->drv_flags);
721 	} else {
722 		ffw = ctucan_read32(priv, CTUCANFD_RX_DATA);
723 	}
724 
725 	if (!FIELD_GET(REG_FRAME_FORMAT_W_RWCNT, ffw))
726 		return -EAGAIN;
727 
728 	if (FIELD_GET(REG_FRAME_FORMAT_W_FDF, ffw))
729 		skb = alloc_canfd_skb(ndev, &cf);
730 	else
731 		skb = alloc_can_skb(ndev, (struct can_frame **)&cf);
732 
733 	if (unlikely(!skb)) {
734 		priv->rxfrm_first_word = ffw;
735 		set_bit(CTUCANFD_FLAG_RX_FFW_BUFFERED, &priv->drv_flags);
736 		return 0;
737 	}
738 
739 	ctucan_read_rx_frame(priv, cf, ffw);
740 
741 	stats->rx_bytes += cf->len;
742 	stats->rx_packets++;
743 	netif_receive_skb(skb);
744 
745 	return 1;
746 }
747 
748 /**
749  * ctucan_read_fault_state() - Reads CTU CAN FDs fault confinement state.
750  * @priv:	Pointer to private data
751  *
752  * Returns: Fault confinement state of controller
753  */
754 static enum can_state ctucan_read_fault_state(struct ctucan_priv *priv)
755 {
756 	u32 fs;
757 	u32 rec_tec;
758 	u32 ewl;
759 
760 	fs = ctucan_read32(priv, CTUCANFD_EWL);
761 	rec_tec = ctucan_read32(priv, CTUCANFD_REC);
762 	ewl = FIELD_GET(REG_EWL_EW_LIMIT, fs);
763 
764 	if (FIELD_GET(REG_EWL_ERA, fs)) {
765 		if (ewl > FIELD_GET(REG_REC_REC_VAL, rec_tec) &&
766 		    ewl > FIELD_GET(REG_REC_TEC_VAL, rec_tec))
767 			return CAN_STATE_ERROR_ACTIVE;
768 		else
769 			return CAN_STATE_ERROR_WARNING;
770 	} else if (FIELD_GET(REG_EWL_ERP, fs)) {
771 		return CAN_STATE_ERROR_PASSIVE;
772 	} else if (FIELD_GET(REG_EWL_BOF, fs)) {
773 		return CAN_STATE_BUS_OFF;
774 	}
775 
776 	WARN(true, "Invalid error state");
777 	return CAN_STATE_ERROR_PASSIVE;
778 }
779 
780 /**
781  * ctucan_get_rec_tec() - Reads REC/TEC counter values from controller
782  * @priv:	Pointer to private data
783  * @bec:	Pointer to Error counter structure
784  */
785 static void ctucan_get_rec_tec(struct ctucan_priv *priv, struct can_berr_counter *bec)
786 {
787 	u32 err_ctrs = ctucan_read32(priv, CTUCANFD_REC);
788 
789 	bec->rxerr = FIELD_GET(REG_REC_REC_VAL, err_ctrs);
790 	bec->txerr = FIELD_GET(REG_REC_TEC_VAL, err_ctrs);
791 }
792 
793 /**
794  * ctucan_err_interrupt() - Error frame ISR
795  * @ndev:	net_device pointer
796  * @isr:	interrupt status register value
797  *
798  * This is the CAN error interrupt and it will check the type of error and forward the error
799  * frame to upper layers.
800  */
801 static void ctucan_err_interrupt(struct net_device *ndev, u32 isr)
802 {
803 	struct ctucan_priv *priv = netdev_priv(ndev);
804 	struct net_device_stats *stats = &ndev->stats;
805 	struct can_frame *cf;
806 	struct sk_buff *skb;
807 	enum can_state state;
808 	struct can_berr_counter bec;
809 	u32 err_capt_alc;
810 	int dologerr = net_ratelimit();
811 
812 	ctucan_get_rec_tec(priv, &bec);
813 	state = ctucan_read_fault_state(priv);
814 	err_capt_alc = ctucan_read32(priv, CTUCANFD_ERR_CAPT);
815 
816 	if (dologerr)
817 		netdev_info(ndev, "%s: ISR = 0x%08x, rxerr %d, txerr %d, error type %lu, pos %lu, ALC id_field %lu, bit %lu\n",
818 			    __func__, isr, bec.rxerr, bec.txerr,
819 			    FIELD_GET(REG_ERR_CAPT_ERR_TYPE, err_capt_alc),
820 			    FIELD_GET(REG_ERR_CAPT_ERR_POS, err_capt_alc),
821 			    FIELD_GET(REG_ERR_CAPT_ALC_ID_FIELD, err_capt_alc),
822 			    FIELD_GET(REG_ERR_CAPT_ALC_BIT, err_capt_alc));
823 
824 	skb = alloc_can_err_skb(ndev, &cf);
825 
826 	/* EWLI: error warning limit condition met
827 	 * FCSI: fault confinement state changed
828 	 * ALI:  arbitration lost (just informative)
829 	 * BEI:  bus error interrupt
830 	 */
831 	if (FIELD_GET(REG_INT_STAT_FCSI, isr) || FIELD_GET(REG_INT_STAT_EWLI, isr)) {
832 		netdev_info(ndev, "state changes from %s to %s\n",
833 			    ctucan_state_to_str(priv->can.state),
834 			    ctucan_state_to_str(state));
835 
836 		if (priv->can.state == state)
837 			netdev_warn(ndev,
838 				    "current and previous state is the same! (missed interrupt?)\n");
839 
840 		priv->can.state = state;
841 		switch (state) {
842 		case CAN_STATE_BUS_OFF:
843 			priv->can.can_stats.bus_off++;
844 			can_bus_off(ndev);
845 			if (skb)
846 				cf->can_id |= CAN_ERR_BUSOFF;
847 			break;
848 		case CAN_STATE_ERROR_PASSIVE:
849 			priv->can.can_stats.error_passive++;
850 			if (skb) {
851 				cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;
852 				cf->data[1] = (bec.rxerr > 127) ?
853 						CAN_ERR_CRTL_RX_PASSIVE :
854 						CAN_ERR_CRTL_TX_PASSIVE;
855 				cf->data[6] = bec.txerr;
856 				cf->data[7] = bec.rxerr;
857 			}
858 			break;
859 		case CAN_STATE_ERROR_WARNING:
860 			priv->can.can_stats.error_warning++;
861 			if (skb) {
862 				cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;
863 				cf->data[1] |= (bec.txerr > bec.rxerr) ?
864 					CAN_ERR_CRTL_TX_WARNING :
865 					CAN_ERR_CRTL_RX_WARNING;
866 				cf->data[6] = bec.txerr;
867 				cf->data[7] = bec.rxerr;
868 			}
869 			break;
870 		case CAN_STATE_ERROR_ACTIVE:
871 			cf->can_id |= CAN_ERR_CNT;
872 			cf->data[1] = CAN_ERR_CRTL_ACTIVE;
873 			cf->data[6] = bec.txerr;
874 			cf->data[7] = bec.rxerr;
875 			break;
876 		default:
877 			netdev_warn(ndev, "unhandled error state (%d:%s)!\n",
878 				    state, ctucan_state_to_str(state));
879 			break;
880 		}
881 	}
882 
883 	/* Check for Arbitration Lost interrupt */
884 	if (FIELD_GET(REG_INT_STAT_ALI, isr)) {
885 		if (dologerr)
886 			netdev_info(ndev, "arbitration lost\n");
887 		priv->can.can_stats.arbitration_lost++;
888 		if (skb) {
889 			cf->can_id |= CAN_ERR_LOSTARB;
890 			cf->data[0] = CAN_ERR_LOSTARB_UNSPEC;
891 		}
892 	}
893 
894 	/* Check for Bus Error interrupt */
895 	if (FIELD_GET(REG_INT_STAT_BEI, isr)) {
896 		netdev_info(ndev, "bus error\n");
897 		priv->can.can_stats.bus_error++;
898 		stats->rx_errors++;
899 		if (skb) {
900 			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
901 			cf->data[2] = CAN_ERR_PROT_UNSPEC;
902 			cf->data[3] = CAN_ERR_PROT_LOC_UNSPEC;
903 		}
904 	}
905 
906 	if (skb) {
907 		stats->rx_packets++;
908 		stats->rx_bytes += cf->can_dlc;
909 		netif_rx(skb);
910 	}
911 }
912 
913 /**
914  * ctucan_rx_poll() - Poll routine for rx packets (NAPI)
915  * @napi:	NAPI structure pointer
916  * @quota:	Max number of rx packets to be processed.
917  *
918  * This is the poll routine for rx part. It will process the packets maximux quota value.
919  *
920  * Return: Number of packets received
921  */
922 static int ctucan_rx_poll(struct napi_struct *napi, int quota)
923 {
924 	struct net_device *ndev = napi->dev;
925 	struct ctucan_priv *priv = netdev_priv(ndev);
926 	int work_done = 0;
927 	u32 status;
928 	u32 framecnt;
929 	int res = 1;
930 
931 	framecnt = FIELD_GET(REG_RX_STATUS_RXFRC, ctucan_read32(priv, CTUCANFD_RX_STATUS));
932 	while (framecnt && work_done < quota && res > 0) {
933 		res = ctucan_rx(ndev);
934 		work_done++;
935 		framecnt = FIELD_GET(REG_RX_STATUS_RXFRC, ctucan_read32(priv, CTUCANFD_RX_STATUS));
936 	}
937 
938 	/* Check for RX FIFO Overflow */
939 	status = ctucan_read32(priv, CTUCANFD_STATUS);
940 	if (FIELD_GET(REG_STATUS_DOR, status)) {
941 		struct net_device_stats *stats = &ndev->stats;
942 		struct can_frame *cf;
943 		struct sk_buff *skb;
944 
945 		netdev_info(ndev, "rx_poll: rx fifo overflow\n");
946 		stats->rx_over_errors++;
947 		stats->rx_errors++;
948 		skb = alloc_can_err_skb(ndev, &cf);
949 		if (skb) {
950 			cf->can_id |= CAN_ERR_CRTL;
951 			cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
952 			stats->rx_packets++;
953 			stats->rx_bytes += cf->can_dlc;
954 			netif_rx(skb);
955 		}
956 
957 		/* Clear Data Overrun */
958 		ctucan_write32(priv, CTUCANFD_COMMAND, REG_COMMAND_CDO);
959 	}
960 
961 	if (!framecnt && res != 0) {
962 		if (napi_complete_done(napi, work_done)) {
963 			/* Clear and enable RBNEI. It is level-triggered, so
964 			 * there is no race condition.
965 			 */
966 			ctucan_write32(priv, CTUCANFD_INT_STAT, REG_INT_STAT_RBNEI);
967 			ctucan_write32(priv, CTUCANFD_INT_MASK_CLR, REG_INT_STAT_RBNEI);
968 		}
969 	}
970 
971 	return work_done;
972 }
973 
974 /**
975  * ctucan_rotate_txb_prio() - Rotates priorities of TXT Buffers
976  * @ndev:	net_device pointer
977  */
978 static void ctucan_rotate_txb_prio(struct net_device *ndev)
979 {
980 	struct ctucan_priv *priv = netdev_priv(ndev);
981 	u32 prio = priv->txb_prio;
982 
983 	prio = (prio << 4) | ((prio >> ((priv->ntxbufs - 1) * 4)) & 0xF);
984 	ctucan_netdev_dbg(ndev, "%s: from 0x%08x to 0x%08x\n", __func__, priv->txb_prio, prio);
985 	priv->txb_prio = prio;
986 	ctucan_write32(priv, CTUCANFD_TX_PRIORITY, prio);
987 }
988 
989 /**
990  * ctucan_tx_interrupt() - Tx done Isr
991  * @ndev:	net_device pointer
992  */
993 static void ctucan_tx_interrupt(struct net_device *ndev)
994 {
995 	struct ctucan_priv *priv = netdev_priv(ndev);
996 	struct net_device_stats *stats = &ndev->stats;
997 	bool first = true;
998 	bool some_buffers_processed;
999 	unsigned long flags;
1000 	enum ctucan_txtb_status txtb_status;
1001 	u32 txtb_id;
1002 
1003 	/*  read tx_status
1004 	 *  if txb[n].finished (bit 2)
1005 	 *	if ok -> echo
1006 	 *	if error / aborted -> ?? (find how to handle oneshot mode)
1007 	 *	txb_tail++
1008 	 */
1009 	do {
1010 		spin_lock_irqsave(&priv->tx_lock, flags);
1011 
1012 		some_buffers_processed = false;
1013 		while ((int)(priv->txb_head - priv->txb_tail) > 0) {
1014 			txtb_id = priv->txb_tail % priv->ntxbufs;
1015 			txtb_status = ctucan_get_tx_status(priv, txtb_id);
1016 
1017 			ctucan_netdev_dbg(ndev, "TXI: TXB#%u: status 0x%x\n", txtb_id, txtb_status);
1018 
1019 			switch (txtb_status) {
1020 			case TXT_TOK:
1021 				ctucan_netdev_dbg(ndev, "TXT_OK\n");
1022 				stats->tx_bytes += can_get_echo_skb(ndev, txtb_id, NULL);
1023 				stats->tx_packets++;
1024 				break;
1025 			case TXT_ERR:
1026 				/* This indicated that retransmit limit has been reached. Obviously
1027 				 * we should not echo the frame, but also not indicate any kind of
1028 				 * error. If desired, it was already reported (possible multiple
1029 				 * times) on each arbitration lost.
1030 				 */
1031 				netdev_warn(ndev, "TXB in Error state\n");
1032 				can_free_echo_skb(ndev, txtb_id, NULL);
1033 				stats->tx_dropped++;
1034 				break;
1035 			case TXT_ABT:
1036 				/* Same as for TXT_ERR, only with different cause. We *could*
1037 				 * re-queue the frame, but multiqueue/abort is not supported yet
1038 				 * anyway.
1039 				 */
1040 				netdev_warn(ndev, "TXB in Aborted state\n");
1041 				can_free_echo_skb(ndev, txtb_id, NULL);
1042 				stats->tx_dropped++;
1043 				break;
1044 			default:
1045 				/* Bug only if the first buffer is not finished, otherwise it is
1046 				 * pretty much expected.
1047 				 */
1048 				if (first) {
1049 					netdev_err(ndev,
1050 						   "BUG: TXB#%u not in a finished state (0x%x)!\n",
1051 						   txtb_id, txtb_status);
1052 					spin_unlock_irqrestore(&priv->tx_lock, flags);
1053 					/* do not clear nor wake */
1054 					return;
1055 				}
1056 				goto clear;
1057 			}
1058 			priv->txb_tail++;
1059 			first = false;
1060 			some_buffers_processed = true;
1061 			/* Adjust priorities *before* marking the buffer as empty. */
1062 			ctucan_rotate_txb_prio(ndev);
1063 			ctucan_give_txtb_cmd(priv, TXT_CMD_SET_EMPTY, txtb_id);
1064 		}
1065 clear:
1066 		spin_unlock_irqrestore(&priv->tx_lock, flags);
1067 
1068 		/* If no buffers were processed this time, we cannot clear - that would introduce
1069 		 * a race condition.
1070 		 */
1071 		if (some_buffers_processed) {
1072 			/* Clear the interrupt again. We do not want to receive again interrupt for
1073 			 * the buffer already handled. If it is the last finished one then it would
1074 			 * cause log of spurious interrupt.
1075 			 */
1076 			ctucan_write32(priv, CTUCANFD_INT_STAT, REG_INT_STAT_TXBHCI);
1077 		}
1078 	} while (some_buffers_processed);
1079 
1080 	spin_lock_irqsave(&priv->tx_lock, flags);
1081 
1082 	/* Check if at least one TX buffer is free */
1083 	if (CTU_CAN_FD_TXTNF(priv))
1084 		netif_wake_queue(ndev);
1085 
1086 	spin_unlock_irqrestore(&priv->tx_lock, flags);
1087 }
1088 
1089 /**
1090  * ctucan_interrupt() - CAN Isr
1091  * @irq:	irq number
1092  * @dev_id:	device id pointer
1093  *
1094  * This is the CTU CAN FD ISR. It checks for the type of interrupt
1095  * and invokes the corresponding ISR.
1096  *
1097  * Return:
1098  * IRQ_NONE - If CAN device is in sleep mode, IRQ_HANDLED otherwise
1099  */
1100 static irqreturn_t ctucan_interrupt(int irq, void *dev_id)
1101 {
1102 	struct net_device *ndev = (struct net_device *)dev_id;
1103 	struct ctucan_priv *priv = netdev_priv(ndev);
1104 	u32 isr, icr;
1105 	u32 imask;
1106 	int irq_loops;
1107 
1108 	for (irq_loops = 0; irq_loops < 10000; irq_loops++) {
1109 		/* Get the interrupt status */
1110 		isr = ctucan_read32(priv, CTUCANFD_INT_STAT);
1111 
1112 		if (!isr)
1113 			return irq_loops ? IRQ_HANDLED : IRQ_NONE;
1114 
1115 		/* Receive Buffer Not Empty Interrupt */
1116 		if (FIELD_GET(REG_INT_STAT_RBNEI, isr)) {
1117 			ctucan_netdev_dbg(ndev, "RXBNEI\n");
1118 			/* Mask RXBNEI the first, then clear interrupt and schedule NAPI. Even if
1119 			 * another IRQ fires, RBNEI will always be 0 (masked).
1120 			 */
1121 			icr = REG_INT_STAT_RBNEI;
1122 			ctucan_write32(priv, CTUCANFD_INT_MASK_SET, icr);
1123 			ctucan_write32(priv, CTUCANFD_INT_STAT, icr);
1124 			napi_schedule(&priv->napi);
1125 		}
1126 
1127 		/* TXT Buffer HW Command Interrupt */
1128 		if (FIELD_GET(REG_INT_STAT_TXBHCI, isr)) {
1129 			ctucan_netdev_dbg(ndev, "TXBHCI\n");
1130 			/* Cleared inside */
1131 			ctucan_tx_interrupt(ndev);
1132 		}
1133 
1134 		/* Error interrupts */
1135 		if (FIELD_GET(REG_INT_STAT_EWLI, isr) ||
1136 		    FIELD_GET(REG_INT_STAT_FCSI, isr) ||
1137 		    FIELD_GET(REG_INT_STAT_ALI, isr)) {
1138 			icr = isr & (REG_INT_STAT_EWLI | REG_INT_STAT_FCSI | REG_INT_STAT_ALI);
1139 
1140 			ctucan_netdev_dbg(ndev, "some ERR interrupt: clearing 0x%08x\n", icr);
1141 			ctucan_write32(priv, CTUCANFD_INT_STAT, icr);
1142 			ctucan_err_interrupt(ndev, isr);
1143 		}
1144 		/* Ignore RI, TI, LFI, RFI, BSI */
1145 	}
1146 
1147 	netdev_err(ndev, "%s: stuck interrupt (isr=0x%08x), stopping\n", __func__, isr);
1148 
1149 	if (FIELD_GET(REG_INT_STAT_TXBHCI, isr)) {
1150 		int i;
1151 
1152 		netdev_err(ndev, "txb_head=0x%08x txb_tail=0x%08x\n",
1153 			   priv->txb_head, priv->txb_tail);
1154 		for (i = 0; i < priv->ntxbufs; i++) {
1155 			u32 status = ctucan_get_tx_status(priv, i);
1156 
1157 			netdev_err(ndev, "txb[%d] txb status=0x%08x\n", i, status);
1158 		}
1159 	}
1160 
1161 	imask = 0xffffffff;
1162 	ctucan_write32(priv, CTUCANFD_INT_ENA_CLR, imask);
1163 	ctucan_write32(priv, CTUCANFD_INT_MASK_SET, imask);
1164 
1165 	return IRQ_HANDLED;
1166 }
1167 
1168 /**
1169  * ctucan_chip_stop() - Driver stop routine
1170  * @ndev:	Pointer to net_device structure
1171  *
1172  * This is the drivers stop routine. It will disable the
1173  * interrupts and disable the controller.
1174  */
1175 static void ctucan_chip_stop(struct net_device *ndev)
1176 {
1177 	struct ctucan_priv *priv = netdev_priv(ndev);
1178 	u32 mask = 0xffffffff;
1179 	u32 mode;
1180 
1181 	/* Disable interrupts and disable CAN */
1182 	ctucan_write32(priv, CTUCANFD_INT_ENA_CLR, mask);
1183 	ctucan_write32(priv, CTUCANFD_INT_MASK_SET, mask);
1184 	mode = ctucan_read32(priv, CTUCANFD_MODE);
1185 	mode &= ~REG_MODE_ENA;
1186 	ctucan_write32(priv, CTUCANFD_MODE, mode);
1187 
1188 	priv->can.state = CAN_STATE_STOPPED;
1189 }
1190 
1191 /**
1192  * ctucan_open() - Driver open routine
1193  * @ndev:	Pointer to net_device structure
1194  *
1195  * This is the driver open routine.
1196  * Return: 0 on success and failure value on error
1197  */
1198 static int ctucan_open(struct net_device *ndev)
1199 {
1200 	struct ctucan_priv *priv = netdev_priv(ndev);
1201 	int ret;
1202 
1203 	ret = pm_runtime_get_sync(priv->dev);
1204 	if (ret < 0) {
1205 		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
1206 			   __func__, ret);
1207 		pm_runtime_put_noidle(priv->dev);
1208 		return ret;
1209 	}
1210 
1211 	ret = ctucan_reset(ndev);
1212 	if (ret < 0)
1213 		goto err_reset;
1214 
1215 	/* Common open */
1216 	ret = open_candev(ndev);
1217 	if (ret) {
1218 		netdev_warn(ndev, "open_candev failed!\n");
1219 		goto err_open;
1220 	}
1221 
1222 	ret = request_irq(ndev->irq, ctucan_interrupt, priv->irq_flags, ndev->name, ndev);
1223 	if (ret < 0) {
1224 		netdev_err(ndev, "irq allocation for CAN failed\n");
1225 		goto err_irq;
1226 	}
1227 
1228 	ret = ctucan_chip_start(ndev);
1229 	if (ret < 0) {
1230 		netdev_err(ndev, "ctucan_chip_start failed!\n");
1231 		goto err_chip_start;
1232 	}
1233 
1234 	netdev_info(ndev, "ctu_can_fd device registered\n");
1235 	napi_enable(&priv->napi);
1236 	netif_start_queue(ndev);
1237 
1238 	return 0;
1239 
1240 err_chip_start:
1241 	free_irq(ndev->irq, ndev);
1242 err_irq:
1243 	close_candev(ndev);
1244 err_open:
1245 err_reset:
1246 	pm_runtime_put(priv->dev);
1247 
1248 	return ret;
1249 }
1250 
1251 /**
1252  * ctucan_close() - Driver close routine
1253  * @ndev:	Pointer to net_device structure
1254  *
1255  * Return: 0 always
1256  */
1257 static int ctucan_close(struct net_device *ndev)
1258 {
1259 	struct ctucan_priv *priv = netdev_priv(ndev);
1260 
1261 	netif_stop_queue(ndev);
1262 	napi_disable(&priv->napi);
1263 	ctucan_chip_stop(ndev);
1264 	free_irq(ndev->irq, ndev);
1265 	close_candev(ndev);
1266 
1267 	pm_runtime_put(priv->dev);
1268 
1269 	return 0;
1270 }
1271 
1272 /**
1273  * ctucan_get_berr_counter() - error counter routine
1274  * @ndev:	Pointer to net_device structure
1275  * @bec:	Pointer to can_berr_counter structure
1276  *
1277  * This is the driver error counter routine.
1278  * Return: 0 on success and failure value on error
1279  */
1280 static int ctucan_get_berr_counter(const struct net_device *ndev, struct can_berr_counter *bec)
1281 {
1282 	struct ctucan_priv *priv = netdev_priv(ndev);
1283 	int ret;
1284 
1285 	ret = pm_runtime_get_sync(priv->dev);
1286 	if (ret < 0) {
1287 		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n", __func__, ret);
1288 		pm_runtime_put_noidle(priv->dev);
1289 		return ret;
1290 	}
1291 
1292 	ctucan_get_rec_tec(priv, bec);
1293 	pm_runtime_put(priv->dev);
1294 
1295 	return 0;
1296 }
1297 
1298 static const struct net_device_ops ctucan_netdev_ops = {
1299 	.ndo_open	= ctucan_open,
1300 	.ndo_stop	= ctucan_close,
1301 	.ndo_start_xmit	= ctucan_start_xmit,
1302 	.ndo_change_mtu	= can_change_mtu,
1303 };
1304 
1305 static const struct ethtool_ops ctucan_ethtool_ops = {
1306 	.get_ts_info = ethtool_op_get_ts_info,
1307 };
1308 
1309 int ctucan_suspend(struct device *dev)
1310 {
1311 	struct net_device *ndev = dev_get_drvdata(dev);
1312 	struct ctucan_priv *priv = netdev_priv(ndev);
1313 
1314 	if (netif_running(ndev)) {
1315 		netif_stop_queue(ndev);
1316 		netif_device_detach(ndev);
1317 	}
1318 
1319 	priv->can.state = CAN_STATE_SLEEPING;
1320 
1321 	return 0;
1322 }
1323 EXPORT_SYMBOL(ctucan_suspend);
1324 
1325 int ctucan_resume(struct device *dev)
1326 {
1327 	struct net_device *ndev = dev_get_drvdata(dev);
1328 	struct ctucan_priv *priv = netdev_priv(ndev);
1329 
1330 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
1331 
1332 	if (netif_running(ndev)) {
1333 		netif_device_attach(ndev);
1334 		netif_start_queue(ndev);
1335 	}
1336 
1337 	return 0;
1338 }
1339 EXPORT_SYMBOL(ctucan_resume);
1340 
1341 int ctucan_probe_common(struct device *dev, void __iomem *addr, int irq, unsigned int ntxbufs,
1342 			unsigned long can_clk_rate, int pm_enable_call,
1343 			void (*set_drvdata_fnc)(struct device *dev, struct net_device *ndev))
1344 {
1345 	struct ctucan_priv *priv;
1346 	struct net_device *ndev;
1347 	int ret;
1348 
1349 	/* Create a CAN device instance */
1350 	ndev = alloc_candev(sizeof(struct ctucan_priv), ntxbufs);
1351 	if (!ndev)
1352 		return -ENOMEM;
1353 
1354 	priv = netdev_priv(ndev);
1355 	spin_lock_init(&priv->tx_lock);
1356 	INIT_LIST_HEAD(&priv->peers_on_pdev);
1357 	priv->ntxbufs = ntxbufs;
1358 	priv->dev = dev;
1359 	priv->can.bittiming_const = &ctu_can_fd_bit_timing_max;
1360 	priv->can.data_bittiming_const = &ctu_can_fd_bit_timing_data_max;
1361 	priv->can.do_set_mode = ctucan_do_set_mode;
1362 
1363 	/* Needed for timing adjustment to be performed as soon as possible */
1364 	priv->can.do_set_bittiming = ctucan_set_bittiming;
1365 	priv->can.do_set_data_bittiming = ctucan_set_data_bittiming;
1366 
1367 	priv->can.do_get_berr_counter = ctucan_get_berr_counter;
1368 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK
1369 					| CAN_CTRLMODE_LISTENONLY
1370 					| CAN_CTRLMODE_FD
1371 					| CAN_CTRLMODE_PRESUME_ACK
1372 					| CAN_CTRLMODE_BERR_REPORTING
1373 					| CAN_CTRLMODE_FD_NON_ISO
1374 					| CAN_CTRLMODE_ONE_SHOT;
1375 	priv->mem_base = addr;
1376 
1377 	/* Get IRQ for the device */
1378 	ndev->irq = irq;
1379 	ndev->flags |= IFF_ECHO;	/* We support local echo */
1380 
1381 	if (set_drvdata_fnc)
1382 		set_drvdata_fnc(dev, ndev);
1383 	SET_NETDEV_DEV(ndev, dev);
1384 	ndev->netdev_ops = &ctucan_netdev_ops;
1385 	ndev->ethtool_ops = &ctucan_ethtool_ops;
1386 
1387 	/* Getting the can_clk info */
1388 	if (!can_clk_rate) {
1389 		priv->can_clk = devm_clk_get(dev, NULL);
1390 		if (IS_ERR(priv->can_clk)) {
1391 			dev_err(dev, "Device clock not found.\n");
1392 			ret = PTR_ERR(priv->can_clk);
1393 			goto err_free;
1394 		}
1395 		can_clk_rate = clk_get_rate(priv->can_clk);
1396 	}
1397 
1398 	priv->write_reg = ctucan_write32_le;
1399 	priv->read_reg = ctucan_read32_le;
1400 
1401 	if (pm_enable_call)
1402 		pm_runtime_enable(dev);
1403 	ret = pm_runtime_get_sync(dev);
1404 	if (ret < 0) {
1405 		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
1406 			   __func__, ret);
1407 		pm_runtime_put_noidle(priv->dev);
1408 		goto err_pmdisable;
1409 	}
1410 
1411 	/* Check for big-endianity and set according IO-accessors */
1412 	if ((ctucan_read32(priv, CTUCANFD_DEVICE_ID) & 0xFFFF) != CTUCANFD_ID) {
1413 		priv->write_reg = ctucan_write32_be;
1414 		priv->read_reg = ctucan_read32_be;
1415 		if ((ctucan_read32(priv, CTUCANFD_DEVICE_ID) & 0xFFFF) != CTUCANFD_ID) {
1416 			netdev_err(ndev, "CTU_CAN_FD signature not found\n");
1417 			ret = -ENODEV;
1418 			goto err_deviceoff;
1419 		}
1420 	}
1421 
1422 	ret = ctucan_reset(ndev);
1423 	if (ret < 0)
1424 		goto err_deviceoff;
1425 
1426 	priv->can.clock.freq = can_clk_rate;
1427 
1428 	netif_napi_add(ndev, &priv->napi, ctucan_rx_poll, NAPI_POLL_WEIGHT);
1429 
1430 	ret = register_candev(ndev);
1431 	if (ret) {
1432 		dev_err(dev, "fail to register failed (err=%d)\n", ret);
1433 		goto err_deviceoff;
1434 	}
1435 
1436 	pm_runtime_put(dev);
1437 
1438 	netdev_dbg(ndev, "mem_base=0x%p irq=%d clock=%d, no. of txt buffers:%d\n",
1439 		   priv->mem_base, ndev->irq, priv->can.clock.freq, priv->ntxbufs);
1440 
1441 	return 0;
1442 
1443 err_deviceoff:
1444 	pm_runtime_put(priv->dev);
1445 err_pmdisable:
1446 	if (pm_enable_call)
1447 		pm_runtime_disable(dev);
1448 err_free:
1449 	list_del_init(&priv->peers_on_pdev);
1450 	free_candev(ndev);
1451 	return ret;
1452 }
1453 EXPORT_SYMBOL(ctucan_probe_common);
1454 
1455 MODULE_LICENSE("GPL");
1456 MODULE_AUTHOR("Martin Jerabek <martin.jerabek01@gmail.com>");
1457 MODULE_AUTHOR("Pavel Pisa <pisa@cmp.felk.cvut.cz>");
1458 MODULE_AUTHOR("Ondrej Ille <ondrej.ille@gmail.com>");
1459 MODULE_DESCRIPTION("CTU CAN FD interface");
1460