xref: /linux/drivers/net/can/m_can/m_can.c (revision b58b13f156c00c2457035b7071eaaac105fe6836)
1 // SPDX-License-Identifier: GPL-2.0
2 // CAN bus driver for Bosch M_CAN controller
3 // Copyright (C) 2014 Freescale Semiconductor, Inc.
4 //      Dong Aisheng <b29396@freescale.com>
5 // Copyright (C) 2018-19 Texas Instruments Incorporated - http://www.ti.com/
6 
7 /* Bosch M_CAN user manual can be obtained from:
8  * https://github.com/linux-can/can-doc/tree/master/m_can
9  */
10 
11 #include <linux/bitfield.h>
12 #include <linux/can/dev.h>
13 #include <linux/ethtool.h>
14 #include <linux/hrtimer.h>
15 #include <linux/interrupt.h>
16 #include <linux/io.h>
17 #include <linux/iopoll.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/netdevice.h>
21 #include <linux/of.h>
22 #include <linux/phy/phy.h>
23 #include <linux/pinctrl/consumer.h>
24 #include <linux/platform_device.h>
25 #include <linux/pm_runtime.h>
26 
27 #include "m_can.h"
28 
29 /* registers definition */
30 enum m_can_reg {
31 	M_CAN_CREL	= 0x0,
32 	M_CAN_ENDN	= 0x4,
33 	M_CAN_CUST	= 0x8,
34 	M_CAN_DBTP	= 0xc,
35 	M_CAN_TEST	= 0x10,
36 	M_CAN_RWD	= 0x14,
37 	M_CAN_CCCR	= 0x18,
38 	M_CAN_NBTP	= 0x1c,
39 	M_CAN_TSCC	= 0x20,
40 	M_CAN_TSCV	= 0x24,
41 	M_CAN_TOCC	= 0x28,
42 	M_CAN_TOCV	= 0x2c,
43 	M_CAN_ECR	= 0x40,
44 	M_CAN_PSR	= 0x44,
45 	/* TDCR Register only available for version >=3.1.x */
46 	M_CAN_TDCR	= 0x48,
47 	M_CAN_IR	= 0x50,
48 	M_CAN_IE	= 0x54,
49 	M_CAN_ILS	= 0x58,
50 	M_CAN_ILE	= 0x5c,
51 	M_CAN_GFC	= 0x80,
52 	M_CAN_SIDFC	= 0x84,
53 	M_CAN_XIDFC	= 0x88,
54 	M_CAN_XIDAM	= 0x90,
55 	M_CAN_HPMS	= 0x94,
56 	M_CAN_NDAT1	= 0x98,
57 	M_CAN_NDAT2	= 0x9c,
58 	M_CAN_RXF0C	= 0xa0,
59 	M_CAN_RXF0S	= 0xa4,
60 	M_CAN_RXF0A	= 0xa8,
61 	M_CAN_RXBC	= 0xac,
62 	M_CAN_RXF1C	= 0xb0,
63 	M_CAN_RXF1S	= 0xb4,
64 	M_CAN_RXF1A	= 0xb8,
65 	M_CAN_RXESC	= 0xbc,
66 	M_CAN_TXBC	= 0xc0,
67 	M_CAN_TXFQS	= 0xc4,
68 	M_CAN_TXESC	= 0xc8,
69 	M_CAN_TXBRP	= 0xcc,
70 	M_CAN_TXBAR	= 0xd0,
71 	M_CAN_TXBCR	= 0xd4,
72 	M_CAN_TXBTO	= 0xd8,
73 	M_CAN_TXBCF	= 0xdc,
74 	M_CAN_TXBTIE	= 0xe0,
75 	M_CAN_TXBCIE	= 0xe4,
76 	M_CAN_TXEFC	= 0xf0,
77 	M_CAN_TXEFS	= 0xf4,
78 	M_CAN_TXEFA	= 0xf8,
79 };
80 
81 /* message ram configuration data length */
82 #define MRAM_CFG_LEN	8
83 
84 /* Core Release Register (CREL) */
85 #define CREL_REL_MASK		GENMASK(31, 28)
86 #define CREL_STEP_MASK		GENMASK(27, 24)
87 #define CREL_SUBSTEP_MASK	GENMASK(23, 20)
88 
89 /* Data Bit Timing & Prescaler Register (DBTP) */
90 #define DBTP_TDC		BIT(23)
91 #define DBTP_DBRP_MASK		GENMASK(20, 16)
92 #define DBTP_DTSEG1_MASK	GENMASK(12, 8)
93 #define DBTP_DTSEG2_MASK	GENMASK(7, 4)
94 #define DBTP_DSJW_MASK		GENMASK(3, 0)
95 
96 /* Transmitter Delay Compensation Register (TDCR) */
97 #define TDCR_TDCO_MASK		GENMASK(14, 8)
98 #define TDCR_TDCF_MASK		GENMASK(6, 0)
99 
100 /* Test Register (TEST) */
101 #define TEST_LBCK		BIT(4)
102 
103 /* CC Control Register (CCCR) */
104 #define CCCR_TXP		BIT(14)
105 #define CCCR_TEST		BIT(7)
106 #define CCCR_DAR		BIT(6)
107 #define CCCR_MON		BIT(5)
108 #define CCCR_CSR		BIT(4)
109 #define CCCR_CSA		BIT(3)
110 #define CCCR_ASM		BIT(2)
111 #define CCCR_CCE		BIT(1)
112 #define CCCR_INIT		BIT(0)
113 /* for version 3.0.x */
114 #define CCCR_CMR_MASK		GENMASK(11, 10)
115 #define CCCR_CMR_CANFD		0x1
116 #define CCCR_CMR_CANFD_BRS	0x2
117 #define CCCR_CMR_CAN		0x3
118 #define CCCR_CME_MASK		GENMASK(9, 8)
119 #define CCCR_CME_CAN		0
120 #define CCCR_CME_CANFD		0x1
121 #define CCCR_CME_CANFD_BRS	0x2
122 /* for version >=3.1.x */
123 #define CCCR_EFBI		BIT(13)
124 #define CCCR_PXHD		BIT(12)
125 #define CCCR_BRSE		BIT(9)
126 #define CCCR_FDOE		BIT(8)
127 /* for version >=3.2.x */
128 #define CCCR_NISO		BIT(15)
129 /* for version >=3.3.x */
130 #define CCCR_WMM		BIT(11)
131 #define CCCR_UTSU		BIT(10)
132 
133 /* Nominal Bit Timing & Prescaler Register (NBTP) */
134 #define NBTP_NSJW_MASK		GENMASK(31, 25)
135 #define NBTP_NBRP_MASK		GENMASK(24, 16)
136 #define NBTP_NTSEG1_MASK	GENMASK(15, 8)
137 #define NBTP_NTSEG2_MASK	GENMASK(6, 0)
138 
139 /* Timestamp Counter Configuration Register (TSCC) */
140 #define TSCC_TCP_MASK		GENMASK(19, 16)
141 #define TSCC_TSS_MASK		GENMASK(1, 0)
142 #define TSCC_TSS_DISABLE	0x0
143 #define TSCC_TSS_INTERNAL	0x1
144 #define TSCC_TSS_EXTERNAL	0x2
145 
146 /* Timestamp Counter Value Register (TSCV) */
147 #define TSCV_TSC_MASK		GENMASK(15, 0)
148 
149 /* Error Counter Register (ECR) */
150 #define ECR_RP			BIT(15)
151 #define ECR_REC_MASK		GENMASK(14, 8)
152 #define ECR_TEC_MASK		GENMASK(7, 0)
153 
154 /* Protocol Status Register (PSR) */
155 #define PSR_BO		BIT(7)
156 #define PSR_EW		BIT(6)
157 #define PSR_EP		BIT(5)
158 #define PSR_LEC_MASK	GENMASK(2, 0)
159 #define PSR_DLEC_MASK	GENMASK(10, 8)
160 
161 /* Interrupt Register (IR) */
162 #define IR_ALL_INT	0xffffffff
163 
164 /* Renamed bits for versions > 3.1.x */
165 #define IR_ARA		BIT(29)
166 #define IR_PED		BIT(28)
167 #define IR_PEA		BIT(27)
168 
169 /* Bits for version 3.0.x */
170 #define IR_STE		BIT(31)
171 #define IR_FOE		BIT(30)
172 #define IR_ACKE		BIT(29)
173 #define IR_BE		BIT(28)
174 #define IR_CRCE		BIT(27)
175 #define IR_WDI		BIT(26)
176 #define IR_BO		BIT(25)
177 #define IR_EW		BIT(24)
178 #define IR_EP		BIT(23)
179 #define IR_ELO		BIT(22)
180 #define IR_BEU		BIT(21)
181 #define IR_BEC		BIT(20)
182 #define IR_DRX		BIT(19)
183 #define IR_TOO		BIT(18)
184 #define IR_MRAF		BIT(17)
185 #define IR_TSW		BIT(16)
186 #define IR_TEFL		BIT(15)
187 #define IR_TEFF		BIT(14)
188 #define IR_TEFW		BIT(13)
189 #define IR_TEFN		BIT(12)
190 #define IR_TFE		BIT(11)
191 #define IR_TCF		BIT(10)
192 #define IR_TC		BIT(9)
193 #define IR_HPM		BIT(8)
194 #define IR_RF1L		BIT(7)
195 #define IR_RF1F		BIT(6)
196 #define IR_RF1W		BIT(5)
197 #define IR_RF1N		BIT(4)
198 #define IR_RF0L		BIT(3)
199 #define IR_RF0F		BIT(2)
200 #define IR_RF0W		BIT(1)
201 #define IR_RF0N		BIT(0)
202 #define IR_ERR_STATE	(IR_BO | IR_EW | IR_EP)
203 
204 /* Interrupts for version 3.0.x */
205 #define IR_ERR_LEC_30X	(IR_STE	| IR_FOE | IR_ACKE | IR_BE | IR_CRCE)
206 #define IR_ERR_BUS_30X	(IR_ERR_LEC_30X | IR_WDI | IR_BEU | IR_BEC | \
207 			 IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | IR_RF1L | \
208 			 IR_RF0L)
209 #define IR_ERR_ALL_30X	(IR_ERR_STATE | IR_ERR_BUS_30X)
210 
211 /* Interrupts for version >= 3.1.x */
212 #define IR_ERR_LEC_31X	(IR_PED | IR_PEA)
213 #define IR_ERR_BUS_31X	(IR_ERR_LEC_31X | IR_WDI | IR_BEU | IR_BEC | \
214 			 IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | IR_RF1L | \
215 			 IR_RF0L)
216 #define IR_ERR_ALL_31X	(IR_ERR_STATE | IR_ERR_BUS_31X)
217 
218 /* Interrupt Line Select (ILS) */
219 #define ILS_ALL_INT0	0x0
220 #define ILS_ALL_INT1	0xFFFFFFFF
221 
222 /* Interrupt Line Enable (ILE) */
223 #define ILE_EINT1	BIT(1)
224 #define ILE_EINT0	BIT(0)
225 
226 /* Rx FIFO 0/1 Configuration (RXF0C/RXF1C) */
227 #define RXFC_FWM_MASK	GENMASK(30, 24)
228 #define RXFC_FS_MASK	GENMASK(22, 16)
229 
230 /* Rx FIFO 0/1 Status (RXF0S/RXF1S) */
231 #define RXFS_RFL	BIT(25)
232 #define RXFS_FF		BIT(24)
233 #define RXFS_FPI_MASK	GENMASK(21, 16)
234 #define RXFS_FGI_MASK	GENMASK(13, 8)
235 #define RXFS_FFL_MASK	GENMASK(6, 0)
236 
237 /* Rx Buffer / FIFO Element Size Configuration (RXESC) */
238 #define RXESC_RBDS_MASK		GENMASK(10, 8)
239 #define RXESC_F1DS_MASK		GENMASK(6, 4)
240 #define RXESC_F0DS_MASK		GENMASK(2, 0)
241 #define RXESC_64B		0x7
242 
243 /* Tx Buffer Configuration (TXBC) */
244 #define TXBC_TFQS_MASK		GENMASK(29, 24)
245 #define TXBC_NDTB_MASK		GENMASK(21, 16)
246 
247 /* Tx FIFO/Queue Status (TXFQS) */
248 #define TXFQS_TFQF		BIT(21)
249 #define TXFQS_TFQPI_MASK	GENMASK(20, 16)
250 #define TXFQS_TFGI_MASK		GENMASK(12, 8)
251 #define TXFQS_TFFL_MASK		GENMASK(5, 0)
252 
253 /* Tx Buffer Element Size Configuration (TXESC) */
254 #define TXESC_TBDS_MASK		GENMASK(2, 0)
255 #define TXESC_TBDS_64B		0x7
256 
257 /* Tx Event FIFO Configuration (TXEFC) */
258 #define TXEFC_EFS_MASK		GENMASK(21, 16)
259 
260 /* Tx Event FIFO Status (TXEFS) */
261 #define TXEFS_TEFL		BIT(25)
262 #define TXEFS_EFF		BIT(24)
263 #define TXEFS_EFGI_MASK		GENMASK(12, 8)
264 #define TXEFS_EFFL_MASK		GENMASK(5, 0)
265 
266 /* Tx Event FIFO Acknowledge (TXEFA) */
267 #define TXEFA_EFAI_MASK		GENMASK(4, 0)
268 
269 /* Message RAM Configuration (in bytes) */
270 #define SIDF_ELEMENT_SIZE	4
271 #define XIDF_ELEMENT_SIZE	8
272 #define RXF0_ELEMENT_SIZE	72
273 #define RXF1_ELEMENT_SIZE	72
274 #define RXB_ELEMENT_SIZE	72
275 #define TXE_ELEMENT_SIZE	8
276 #define TXB_ELEMENT_SIZE	72
277 
278 /* Message RAM Elements */
279 #define M_CAN_FIFO_ID		0x0
280 #define M_CAN_FIFO_DLC		0x4
281 #define M_CAN_FIFO_DATA		0x8
282 
283 /* Rx Buffer Element */
284 /* R0 */
285 #define RX_BUF_ESI		BIT(31)
286 #define RX_BUF_XTD		BIT(30)
287 #define RX_BUF_RTR		BIT(29)
288 /* R1 */
289 #define RX_BUF_ANMF		BIT(31)
290 #define RX_BUF_FDF		BIT(21)
291 #define RX_BUF_BRS		BIT(20)
292 #define RX_BUF_RXTS_MASK	GENMASK(15, 0)
293 
294 /* Tx Buffer Element */
295 /* T0 */
296 #define TX_BUF_ESI		BIT(31)
297 #define TX_BUF_XTD		BIT(30)
298 #define TX_BUF_RTR		BIT(29)
299 /* T1 */
300 #define TX_BUF_EFC		BIT(23)
301 #define TX_BUF_FDF		BIT(21)
302 #define TX_BUF_BRS		BIT(20)
303 #define TX_BUF_MM_MASK		GENMASK(31, 24)
304 #define TX_BUF_DLC_MASK		GENMASK(19, 16)
305 
306 /* Tx event FIFO Element */
307 /* E1 */
308 #define TX_EVENT_MM_MASK	GENMASK(31, 24)
309 #define TX_EVENT_TXTS_MASK	GENMASK(15, 0)
310 
311 /* Hrtimer polling interval */
312 #define HRTIMER_POLL_INTERVAL_MS		1
313 
314 /* The ID and DLC registers are adjacent in M_CAN FIFO memory,
315  * and we can save a (potentially slow) bus round trip by combining
316  * reads and writes to them.
317  */
318 struct id_and_dlc {
319 	u32 id;
320 	u32 dlc;
321 };
322 
323 static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)
324 {
325 	return cdev->ops->read_reg(cdev, reg);
326 }
327 
328 static inline void m_can_write(struct m_can_classdev *cdev, enum m_can_reg reg,
329 			       u32 val)
330 {
331 	cdev->ops->write_reg(cdev, reg, val);
332 }
333 
334 static int
335 m_can_fifo_read(struct m_can_classdev *cdev,
336 		u32 fgi, unsigned int offset, void *val, size_t val_count)
337 {
338 	u32 addr_offset = cdev->mcfg[MRAM_RXF0].off + fgi * RXF0_ELEMENT_SIZE +
339 		offset;
340 
341 	if (val_count == 0)
342 		return 0;
343 
344 	return cdev->ops->read_fifo(cdev, addr_offset, val, val_count);
345 }
346 
347 static int
348 m_can_fifo_write(struct m_can_classdev *cdev,
349 		 u32 fpi, unsigned int offset, const void *val, size_t val_count)
350 {
351 	u32 addr_offset = cdev->mcfg[MRAM_TXB].off + fpi * TXB_ELEMENT_SIZE +
352 		offset;
353 
354 	if (val_count == 0)
355 		return 0;
356 
357 	return cdev->ops->write_fifo(cdev, addr_offset, val, val_count);
358 }
359 
360 static inline int m_can_fifo_write_no_off(struct m_can_classdev *cdev,
361 					  u32 fpi, u32 val)
362 {
363 	return cdev->ops->write_fifo(cdev, fpi, &val, 1);
364 }
365 
366 static int
367 m_can_txe_fifo_read(struct m_can_classdev *cdev, u32 fgi, u32 offset, u32 *val)
368 {
369 	u32 addr_offset = cdev->mcfg[MRAM_TXE].off + fgi * TXE_ELEMENT_SIZE +
370 		offset;
371 
372 	return cdev->ops->read_fifo(cdev, addr_offset, val, 1);
373 }
374 
375 static inline bool _m_can_tx_fifo_full(u32 txfqs)
376 {
377 	return !!(txfqs & TXFQS_TFQF);
378 }
379 
380 static inline bool m_can_tx_fifo_full(struct m_can_classdev *cdev)
381 {
382 	return _m_can_tx_fifo_full(m_can_read(cdev, M_CAN_TXFQS));
383 }
384 
385 static void m_can_config_endisable(struct m_can_classdev *cdev, bool enable)
386 {
387 	u32 cccr = m_can_read(cdev, M_CAN_CCCR);
388 	u32 timeout = 10;
389 	u32 val = 0;
390 
391 	/* Clear the Clock stop request if it was set */
392 	if (cccr & CCCR_CSR)
393 		cccr &= ~CCCR_CSR;
394 
395 	if (enable) {
396 		/* enable m_can configuration */
397 		m_can_write(cdev, M_CAN_CCCR, cccr | CCCR_INIT);
398 		udelay(5);
399 		/* CCCR.CCE can only be set/reset while CCCR.INIT = '1' */
400 		m_can_write(cdev, M_CAN_CCCR, cccr | CCCR_INIT | CCCR_CCE);
401 	} else {
402 		m_can_write(cdev, M_CAN_CCCR, cccr & ~(CCCR_INIT | CCCR_CCE));
403 	}
404 
405 	/* there's a delay for module initialization */
406 	if (enable)
407 		val = CCCR_INIT | CCCR_CCE;
408 
409 	while ((m_can_read(cdev, M_CAN_CCCR) & (CCCR_INIT | CCCR_CCE)) != val) {
410 		if (timeout == 0) {
411 			netdev_warn(cdev->net, "Failed to init module\n");
412 			return;
413 		}
414 		timeout--;
415 		udelay(1);
416 	}
417 }
418 
419 static inline void m_can_enable_all_interrupts(struct m_can_classdev *cdev)
420 {
421 	/* Only interrupt line 0 is used in this driver */
422 	m_can_write(cdev, M_CAN_ILE, ILE_EINT0);
423 }
424 
425 static inline void m_can_disable_all_interrupts(struct m_can_classdev *cdev)
426 {
427 	m_can_write(cdev, M_CAN_ILE, 0x0);
428 }
429 
430 /* Retrieve internal timestamp counter from TSCV.TSC, and shift it to 32-bit
431  * width.
432  */
433 static u32 m_can_get_timestamp(struct m_can_classdev *cdev)
434 {
435 	u32 tscv;
436 	u32 tsc;
437 
438 	tscv = m_can_read(cdev, M_CAN_TSCV);
439 	tsc = FIELD_GET(TSCV_TSC_MASK, tscv);
440 
441 	return (tsc << 16);
442 }
443 
444 static void m_can_clean(struct net_device *net)
445 {
446 	struct m_can_classdev *cdev = netdev_priv(net);
447 
448 	if (cdev->tx_skb) {
449 		int putidx = 0;
450 
451 		net->stats.tx_errors++;
452 		if (cdev->version > 30)
453 			putidx = FIELD_GET(TXFQS_TFQPI_MASK,
454 					   m_can_read(cdev, M_CAN_TXFQS));
455 
456 		can_free_echo_skb(cdev->net, putidx, NULL);
457 		cdev->tx_skb = NULL;
458 	}
459 }
460 
461 /* For peripherals, pass skb to rx-offload, which will push skb from
462  * napi. For non-peripherals, RX is done in napi already, so push
463  * directly. timestamp is used to ensure good skb ordering in
464  * rx-offload and is ignored for non-peripherals.
465  */
466 static void m_can_receive_skb(struct m_can_classdev *cdev,
467 			      struct sk_buff *skb,
468 			      u32 timestamp)
469 {
470 	if (cdev->is_peripheral) {
471 		struct net_device_stats *stats = &cdev->net->stats;
472 		int err;
473 
474 		err = can_rx_offload_queue_timestamp(&cdev->offload, skb,
475 						     timestamp);
476 		if (err)
477 			stats->rx_fifo_errors++;
478 	} else {
479 		netif_receive_skb(skb);
480 	}
481 }
482 
483 static int m_can_read_fifo(struct net_device *dev, u32 fgi)
484 {
485 	struct net_device_stats *stats = &dev->stats;
486 	struct m_can_classdev *cdev = netdev_priv(dev);
487 	struct canfd_frame *cf;
488 	struct sk_buff *skb;
489 	struct id_and_dlc fifo_header;
490 	u32 timestamp = 0;
491 	int err;
492 
493 	err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_ID, &fifo_header, 2);
494 	if (err)
495 		goto out_fail;
496 
497 	if (fifo_header.dlc & RX_BUF_FDF)
498 		skb = alloc_canfd_skb(dev, &cf);
499 	else
500 		skb = alloc_can_skb(dev, (struct can_frame **)&cf);
501 	if (!skb) {
502 		stats->rx_dropped++;
503 		return 0;
504 	}
505 
506 	if (fifo_header.dlc & RX_BUF_FDF)
507 		cf->len = can_fd_dlc2len((fifo_header.dlc >> 16) & 0x0F);
508 	else
509 		cf->len = can_cc_dlc2len((fifo_header.dlc >> 16) & 0x0F);
510 
511 	if (fifo_header.id & RX_BUF_XTD)
512 		cf->can_id = (fifo_header.id & CAN_EFF_MASK) | CAN_EFF_FLAG;
513 	else
514 		cf->can_id = (fifo_header.id >> 18) & CAN_SFF_MASK;
515 
516 	if (fifo_header.id & RX_BUF_ESI) {
517 		cf->flags |= CANFD_ESI;
518 		netdev_dbg(dev, "ESI Error\n");
519 	}
520 
521 	if (!(fifo_header.dlc & RX_BUF_FDF) && (fifo_header.id & RX_BUF_RTR)) {
522 		cf->can_id |= CAN_RTR_FLAG;
523 	} else {
524 		if (fifo_header.dlc & RX_BUF_BRS)
525 			cf->flags |= CANFD_BRS;
526 
527 		err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DATA,
528 				      cf->data, DIV_ROUND_UP(cf->len, 4));
529 		if (err)
530 			goto out_free_skb;
531 
532 		stats->rx_bytes += cf->len;
533 	}
534 	stats->rx_packets++;
535 
536 	timestamp = FIELD_GET(RX_BUF_RXTS_MASK, fifo_header.dlc) << 16;
537 
538 	m_can_receive_skb(cdev, skb, timestamp);
539 
540 	return 0;
541 
542 out_free_skb:
543 	kfree_skb(skb);
544 out_fail:
545 	netdev_err(dev, "FIFO read returned %d\n", err);
546 	return err;
547 }
548 
549 static int m_can_do_rx_poll(struct net_device *dev, int quota)
550 {
551 	struct m_can_classdev *cdev = netdev_priv(dev);
552 	u32 pkts = 0;
553 	u32 rxfs;
554 	u32 rx_count;
555 	u32 fgi;
556 	int ack_fgi = -1;
557 	int i;
558 	int err = 0;
559 
560 	rxfs = m_can_read(cdev, M_CAN_RXF0S);
561 	if (!(rxfs & RXFS_FFL_MASK)) {
562 		netdev_dbg(dev, "no messages in fifo0\n");
563 		return 0;
564 	}
565 
566 	rx_count = FIELD_GET(RXFS_FFL_MASK, rxfs);
567 	fgi = FIELD_GET(RXFS_FGI_MASK, rxfs);
568 
569 	for (i = 0; i < rx_count && quota > 0; ++i) {
570 		err = m_can_read_fifo(dev, fgi);
571 		if (err)
572 			break;
573 
574 		quota--;
575 		pkts++;
576 		ack_fgi = fgi;
577 		fgi = (++fgi >= cdev->mcfg[MRAM_RXF0].num ? 0 : fgi);
578 	}
579 
580 	if (ack_fgi != -1)
581 		m_can_write(cdev, M_CAN_RXF0A, ack_fgi);
582 
583 	if (err)
584 		return err;
585 
586 	return pkts;
587 }
588 
589 static int m_can_handle_lost_msg(struct net_device *dev)
590 {
591 	struct m_can_classdev *cdev = netdev_priv(dev);
592 	struct net_device_stats *stats = &dev->stats;
593 	struct sk_buff *skb;
594 	struct can_frame *frame;
595 	u32 timestamp = 0;
596 
597 	netdev_err(dev, "msg lost in rxf0\n");
598 
599 	stats->rx_errors++;
600 	stats->rx_over_errors++;
601 
602 	skb = alloc_can_err_skb(dev, &frame);
603 	if (unlikely(!skb))
604 		return 0;
605 
606 	frame->can_id |= CAN_ERR_CRTL;
607 	frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
608 
609 	if (cdev->is_peripheral)
610 		timestamp = m_can_get_timestamp(cdev);
611 
612 	m_can_receive_skb(cdev, skb, timestamp);
613 
614 	return 1;
615 }
616 
617 static int m_can_handle_lec_err(struct net_device *dev,
618 				enum m_can_lec_type lec_type)
619 {
620 	struct m_can_classdev *cdev = netdev_priv(dev);
621 	struct net_device_stats *stats = &dev->stats;
622 	struct can_frame *cf;
623 	struct sk_buff *skb;
624 	u32 timestamp = 0;
625 
626 	cdev->can.can_stats.bus_error++;
627 	stats->rx_errors++;
628 
629 	/* propagate the error condition to the CAN stack */
630 	skb = alloc_can_err_skb(dev, &cf);
631 	if (unlikely(!skb))
632 		return 0;
633 
634 	/* check for 'last error code' which tells us the
635 	 * type of the last error to occur on the CAN bus
636 	 */
637 	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
638 
639 	switch (lec_type) {
640 	case LEC_STUFF_ERROR:
641 		netdev_dbg(dev, "stuff error\n");
642 		cf->data[2] |= CAN_ERR_PROT_STUFF;
643 		break;
644 	case LEC_FORM_ERROR:
645 		netdev_dbg(dev, "form error\n");
646 		cf->data[2] |= CAN_ERR_PROT_FORM;
647 		break;
648 	case LEC_ACK_ERROR:
649 		netdev_dbg(dev, "ack error\n");
650 		cf->data[3] = CAN_ERR_PROT_LOC_ACK;
651 		break;
652 	case LEC_BIT1_ERROR:
653 		netdev_dbg(dev, "bit1 error\n");
654 		cf->data[2] |= CAN_ERR_PROT_BIT1;
655 		break;
656 	case LEC_BIT0_ERROR:
657 		netdev_dbg(dev, "bit0 error\n");
658 		cf->data[2] |= CAN_ERR_PROT_BIT0;
659 		break;
660 	case LEC_CRC_ERROR:
661 		netdev_dbg(dev, "CRC error\n");
662 		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
663 		break;
664 	default:
665 		break;
666 	}
667 
668 	if (cdev->is_peripheral)
669 		timestamp = m_can_get_timestamp(cdev);
670 
671 	m_can_receive_skb(cdev, skb, timestamp);
672 
673 	return 1;
674 }
675 
676 static int __m_can_get_berr_counter(const struct net_device *dev,
677 				    struct can_berr_counter *bec)
678 {
679 	struct m_can_classdev *cdev = netdev_priv(dev);
680 	unsigned int ecr;
681 
682 	ecr = m_can_read(cdev, M_CAN_ECR);
683 	bec->rxerr = FIELD_GET(ECR_REC_MASK, ecr);
684 	bec->txerr = FIELD_GET(ECR_TEC_MASK, ecr);
685 
686 	return 0;
687 }
688 
689 static int m_can_clk_start(struct m_can_classdev *cdev)
690 {
691 	if (cdev->pm_clock_support == 0)
692 		return 0;
693 
694 	return pm_runtime_resume_and_get(cdev->dev);
695 }
696 
697 static void m_can_clk_stop(struct m_can_classdev *cdev)
698 {
699 	if (cdev->pm_clock_support)
700 		pm_runtime_put_sync(cdev->dev);
701 }
702 
703 static int m_can_get_berr_counter(const struct net_device *dev,
704 				  struct can_berr_counter *bec)
705 {
706 	struct m_can_classdev *cdev = netdev_priv(dev);
707 	int err;
708 
709 	err = m_can_clk_start(cdev);
710 	if (err)
711 		return err;
712 
713 	__m_can_get_berr_counter(dev, bec);
714 
715 	m_can_clk_stop(cdev);
716 
717 	return 0;
718 }
719 
720 static int m_can_handle_state_change(struct net_device *dev,
721 				     enum can_state new_state)
722 {
723 	struct m_can_classdev *cdev = netdev_priv(dev);
724 	struct can_frame *cf;
725 	struct sk_buff *skb;
726 	struct can_berr_counter bec;
727 	unsigned int ecr;
728 	u32 timestamp = 0;
729 
730 	switch (new_state) {
731 	case CAN_STATE_ERROR_WARNING:
732 		/* error warning state */
733 		cdev->can.can_stats.error_warning++;
734 		cdev->can.state = CAN_STATE_ERROR_WARNING;
735 		break;
736 	case CAN_STATE_ERROR_PASSIVE:
737 		/* error passive state */
738 		cdev->can.can_stats.error_passive++;
739 		cdev->can.state = CAN_STATE_ERROR_PASSIVE;
740 		break;
741 	case CAN_STATE_BUS_OFF:
742 		/* bus-off state */
743 		cdev->can.state = CAN_STATE_BUS_OFF;
744 		m_can_disable_all_interrupts(cdev);
745 		cdev->can.can_stats.bus_off++;
746 		can_bus_off(dev);
747 		break;
748 	default:
749 		break;
750 	}
751 
752 	/* propagate the error condition to the CAN stack */
753 	skb = alloc_can_err_skb(dev, &cf);
754 	if (unlikely(!skb))
755 		return 0;
756 
757 	__m_can_get_berr_counter(dev, &bec);
758 
759 	switch (new_state) {
760 	case CAN_STATE_ERROR_WARNING:
761 		/* error warning state */
762 		cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;
763 		cf->data[1] = (bec.txerr > bec.rxerr) ?
764 			CAN_ERR_CRTL_TX_WARNING :
765 			CAN_ERR_CRTL_RX_WARNING;
766 		cf->data[6] = bec.txerr;
767 		cf->data[7] = bec.rxerr;
768 		break;
769 	case CAN_STATE_ERROR_PASSIVE:
770 		/* error passive state */
771 		cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;
772 		ecr = m_can_read(cdev, M_CAN_ECR);
773 		if (ecr & ECR_RP)
774 			cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
775 		if (bec.txerr > 127)
776 			cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
777 		cf->data[6] = bec.txerr;
778 		cf->data[7] = bec.rxerr;
779 		break;
780 	case CAN_STATE_BUS_OFF:
781 		/* bus-off state */
782 		cf->can_id |= CAN_ERR_BUSOFF;
783 		break;
784 	default:
785 		break;
786 	}
787 
788 	if (cdev->is_peripheral)
789 		timestamp = m_can_get_timestamp(cdev);
790 
791 	m_can_receive_skb(cdev, skb, timestamp);
792 
793 	return 1;
794 }
795 
796 static int m_can_handle_state_errors(struct net_device *dev, u32 psr)
797 {
798 	struct m_can_classdev *cdev = netdev_priv(dev);
799 	int work_done = 0;
800 
801 	if (psr & PSR_EW && cdev->can.state != CAN_STATE_ERROR_WARNING) {
802 		netdev_dbg(dev, "entered error warning state\n");
803 		work_done += m_can_handle_state_change(dev,
804 						       CAN_STATE_ERROR_WARNING);
805 	}
806 
807 	if (psr & PSR_EP && cdev->can.state != CAN_STATE_ERROR_PASSIVE) {
808 		netdev_dbg(dev, "entered error passive state\n");
809 		work_done += m_can_handle_state_change(dev,
810 						       CAN_STATE_ERROR_PASSIVE);
811 	}
812 
813 	if (psr & PSR_BO && cdev->can.state != CAN_STATE_BUS_OFF) {
814 		netdev_dbg(dev, "entered error bus off state\n");
815 		work_done += m_can_handle_state_change(dev,
816 						       CAN_STATE_BUS_OFF);
817 	}
818 
819 	return work_done;
820 }
821 
822 static void m_can_handle_other_err(struct net_device *dev, u32 irqstatus)
823 {
824 	if (irqstatus & IR_WDI)
825 		netdev_err(dev, "Message RAM Watchdog event due to missing READY\n");
826 	if (irqstatus & IR_BEU)
827 		netdev_err(dev, "Bit Error Uncorrected\n");
828 	if (irqstatus & IR_BEC)
829 		netdev_err(dev, "Bit Error Corrected\n");
830 	if (irqstatus & IR_TOO)
831 		netdev_err(dev, "Timeout reached\n");
832 	if (irqstatus & IR_MRAF)
833 		netdev_err(dev, "Message RAM access failure occurred\n");
834 }
835 
836 static inline bool is_lec_err(u8 lec)
837 {
838 	return lec != LEC_NO_ERROR && lec != LEC_NO_CHANGE;
839 }
840 
841 static inline bool m_can_is_protocol_err(u32 irqstatus)
842 {
843 	return irqstatus & IR_ERR_LEC_31X;
844 }
845 
846 static int m_can_handle_protocol_error(struct net_device *dev, u32 irqstatus)
847 {
848 	struct net_device_stats *stats = &dev->stats;
849 	struct m_can_classdev *cdev = netdev_priv(dev);
850 	struct can_frame *cf;
851 	struct sk_buff *skb;
852 	u32 timestamp = 0;
853 
854 	/* propagate the error condition to the CAN stack */
855 	skb = alloc_can_err_skb(dev, &cf);
856 
857 	/* update tx error stats since there is protocol error */
858 	stats->tx_errors++;
859 
860 	/* update arbitration lost status */
861 	if (cdev->version >= 31 && (irqstatus & IR_PEA)) {
862 		netdev_dbg(dev, "Protocol error in Arbitration fail\n");
863 		cdev->can.can_stats.arbitration_lost++;
864 		if (skb) {
865 			cf->can_id |= CAN_ERR_LOSTARB;
866 			cf->data[0] |= CAN_ERR_LOSTARB_UNSPEC;
867 		}
868 	}
869 
870 	if (unlikely(!skb)) {
871 		netdev_dbg(dev, "allocation of skb failed\n");
872 		return 0;
873 	}
874 
875 	if (cdev->is_peripheral)
876 		timestamp = m_can_get_timestamp(cdev);
877 
878 	m_can_receive_skb(cdev, skb, timestamp);
879 
880 	return 1;
881 }
882 
883 static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus,
884 				   u32 psr)
885 {
886 	struct m_can_classdev *cdev = netdev_priv(dev);
887 	int work_done = 0;
888 
889 	if (irqstatus & IR_RF0L)
890 		work_done += m_can_handle_lost_msg(dev);
891 
892 	/* handle lec errors on the bus */
893 	if (cdev->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) {
894 		u8 lec = FIELD_GET(PSR_LEC_MASK, psr);
895 		u8 dlec = FIELD_GET(PSR_DLEC_MASK, psr);
896 
897 		if (is_lec_err(lec)) {
898 			netdev_dbg(dev, "Arbitration phase error detected\n");
899 			work_done += m_can_handle_lec_err(dev, lec);
900 		}
901 
902 		if (is_lec_err(dlec)) {
903 			netdev_dbg(dev, "Data phase error detected\n");
904 			work_done += m_can_handle_lec_err(dev, dlec);
905 		}
906 	}
907 
908 	/* handle protocol errors in arbitration phase */
909 	if ((cdev->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
910 	    m_can_is_protocol_err(irqstatus))
911 		work_done += m_can_handle_protocol_error(dev, irqstatus);
912 
913 	/* other unproccessed error interrupts */
914 	m_can_handle_other_err(dev, irqstatus);
915 
916 	return work_done;
917 }
918 
919 static int m_can_rx_handler(struct net_device *dev, int quota, u32 irqstatus)
920 {
921 	struct m_can_classdev *cdev = netdev_priv(dev);
922 	int rx_work_or_err;
923 	int work_done = 0;
924 
925 	if (!irqstatus)
926 		goto end;
927 
928 	/* Errata workaround for issue "Needless activation of MRAF irq"
929 	 * During frame reception while the MCAN is in Error Passive state
930 	 * and the Receive Error Counter has the value MCAN_ECR.REC = 127,
931 	 * it may happen that MCAN_IR.MRAF is set although there was no
932 	 * Message RAM access failure.
933 	 * If MCAN_IR.MRAF is enabled, an interrupt to the Host CPU is generated
934 	 * The Message RAM Access Failure interrupt routine needs to check
935 	 * whether MCAN_ECR.RP = ’1’ and MCAN_ECR.REC = 127.
936 	 * In this case, reset MCAN_IR.MRAF. No further action is required.
937 	 */
938 	if (cdev->version <= 31 && irqstatus & IR_MRAF &&
939 	    m_can_read(cdev, M_CAN_ECR) & ECR_RP) {
940 		struct can_berr_counter bec;
941 
942 		__m_can_get_berr_counter(dev, &bec);
943 		if (bec.rxerr == 127) {
944 			m_can_write(cdev, M_CAN_IR, IR_MRAF);
945 			irqstatus &= ~IR_MRAF;
946 		}
947 	}
948 
949 	if (irqstatus & IR_ERR_STATE)
950 		work_done += m_can_handle_state_errors(dev,
951 						       m_can_read(cdev, M_CAN_PSR));
952 
953 	if (irqstatus & IR_ERR_BUS_30X)
954 		work_done += m_can_handle_bus_errors(dev, irqstatus,
955 						     m_can_read(cdev, M_CAN_PSR));
956 
957 	if (irqstatus & IR_RF0N) {
958 		rx_work_or_err = m_can_do_rx_poll(dev, (quota - work_done));
959 		if (rx_work_or_err < 0)
960 			return rx_work_or_err;
961 
962 		work_done += rx_work_or_err;
963 	}
964 end:
965 	return work_done;
966 }
967 
968 static int m_can_rx_peripheral(struct net_device *dev, u32 irqstatus)
969 {
970 	struct m_can_classdev *cdev = netdev_priv(dev);
971 	int work_done;
972 
973 	work_done = m_can_rx_handler(dev, NAPI_POLL_WEIGHT, irqstatus);
974 
975 	/* Don't re-enable interrupts if the driver had a fatal error
976 	 * (e.g., FIFO read failure).
977 	 */
978 	if (work_done < 0)
979 		m_can_disable_all_interrupts(cdev);
980 
981 	return work_done;
982 }
983 
984 static int m_can_poll(struct napi_struct *napi, int quota)
985 {
986 	struct net_device *dev = napi->dev;
987 	struct m_can_classdev *cdev = netdev_priv(dev);
988 	int work_done;
989 	u32 irqstatus;
990 
991 	irqstatus = cdev->irqstatus | m_can_read(cdev, M_CAN_IR);
992 
993 	work_done = m_can_rx_handler(dev, quota, irqstatus);
994 
995 	/* Don't re-enable interrupts if the driver had a fatal error
996 	 * (e.g., FIFO read failure).
997 	 */
998 	if (work_done >= 0 && work_done < quota) {
999 		napi_complete_done(napi, work_done);
1000 		m_can_enable_all_interrupts(cdev);
1001 	}
1002 
1003 	return work_done;
1004 }
1005 
1006 /* Echo tx skb and update net stats. Peripherals use rx-offload for
1007  * echo. timestamp is used for peripherals to ensure correct ordering
1008  * by rx-offload, and is ignored for non-peripherals.
1009  */
1010 static void m_can_tx_update_stats(struct m_can_classdev *cdev,
1011 				  unsigned int msg_mark,
1012 				  u32 timestamp)
1013 {
1014 	struct net_device *dev = cdev->net;
1015 	struct net_device_stats *stats = &dev->stats;
1016 
1017 	if (cdev->is_peripheral)
1018 		stats->tx_bytes +=
1019 			can_rx_offload_get_echo_skb_queue_timestamp(&cdev->offload,
1020 								    msg_mark,
1021 								    timestamp,
1022 								    NULL);
1023 	else
1024 		stats->tx_bytes += can_get_echo_skb(dev, msg_mark, NULL);
1025 
1026 	stats->tx_packets++;
1027 }
1028 
1029 static int m_can_echo_tx_event(struct net_device *dev)
1030 {
1031 	u32 txe_count = 0;
1032 	u32 m_can_txefs;
1033 	u32 fgi = 0;
1034 	int ack_fgi = -1;
1035 	int i = 0;
1036 	int err = 0;
1037 	unsigned int msg_mark;
1038 
1039 	struct m_can_classdev *cdev = netdev_priv(dev);
1040 
1041 	/* read tx event fifo status */
1042 	m_can_txefs = m_can_read(cdev, M_CAN_TXEFS);
1043 
1044 	/* Get Tx Event fifo element count */
1045 	txe_count = FIELD_GET(TXEFS_EFFL_MASK, m_can_txefs);
1046 	fgi = FIELD_GET(TXEFS_EFGI_MASK, m_can_txefs);
1047 
1048 	/* Get and process all sent elements */
1049 	for (i = 0; i < txe_count; i++) {
1050 		u32 txe, timestamp = 0;
1051 
1052 		/* get message marker, timestamp */
1053 		err = m_can_txe_fifo_read(cdev, fgi, 4, &txe);
1054 		if (err) {
1055 			netdev_err(dev, "TXE FIFO read returned %d\n", err);
1056 			break;
1057 		}
1058 
1059 		msg_mark = FIELD_GET(TX_EVENT_MM_MASK, txe);
1060 		timestamp = FIELD_GET(TX_EVENT_TXTS_MASK, txe) << 16;
1061 
1062 		ack_fgi = fgi;
1063 		fgi = (++fgi >= cdev->mcfg[MRAM_TXE].num ? 0 : fgi);
1064 
1065 		/* update stats */
1066 		m_can_tx_update_stats(cdev, msg_mark, timestamp);
1067 	}
1068 
1069 	if (ack_fgi != -1)
1070 		m_can_write(cdev, M_CAN_TXEFA, FIELD_PREP(TXEFA_EFAI_MASK,
1071 							  ack_fgi));
1072 
1073 	return err;
1074 }
1075 
1076 static irqreturn_t m_can_isr(int irq, void *dev_id)
1077 {
1078 	struct net_device *dev = (struct net_device *)dev_id;
1079 	struct m_can_classdev *cdev = netdev_priv(dev);
1080 	u32 ir;
1081 
1082 	if (pm_runtime_suspended(cdev->dev))
1083 		return IRQ_NONE;
1084 	ir = m_can_read(cdev, M_CAN_IR);
1085 	if (!ir)
1086 		return IRQ_NONE;
1087 
1088 	/* ACK all irqs */
1089 	m_can_write(cdev, M_CAN_IR, ir);
1090 
1091 	if (cdev->ops->clear_interrupts)
1092 		cdev->ops->clear_interrupts(cdev);
1093 
1094 	/* schedule NAPI in case of
1095 	 * - rx IRQ
1096 	 * - state change IRQ
1097 	 * - bus error IRQ and bus error reporting
1098 	 */
1099 	if ((ir & IR_RF0N) || (ir & IR_ERR_ALL_30X)) {
1100 		cdev->irqstatus = ir;
1101 		if (!cdev->is_peripheral) {
1102 			m_can_disable_all_interrupts(cdev);
1103 			napi_schedule(&cdev->napi);
1104 		} else if (m_can_rx_peripheral(dev, ir) < 0) {
1105 			goto out_fail;
1106 		}
1107 	}
1108 
1109 	if (cdev->version == 30) {
1110 		if (ir & IR_TC) {
1111 			/* Transmission Complete Interrupt*/
1112 			u32 timestamp = 0;
1113 
1114 			if (cdev->is_peripheral)
1115 				timestamp = m_can_get_timestamp(cdev);
1116 			m_can_tx_update_stats(cdev, 0, timestamp);
1117 			netif_wake_queue(dev);
1118 		}
1119 	} else  {
1120 		if (ir & IR_TEFN) {
1121 			/* New TX FIFO Element arrived */
1122 			if (m_can_echo_tx_event(dev) != 0)
1123 				goto out_fail;
1124 
1125 			if (netif_queue_stopped(dev) &&
1126 			    !m_can_tx_fifo_full(cdev))
1127 				netif_wake_queue(dev);
1128 		}
1129 	}
1130 
1131 	if (cdev->is_peripheral)
1132 		can_rx_offload_threaded_irq_finish(&cdev->offload);
1133 
1134 	return IRQ_HANDLED;
1135 
1136 out_fail:
1137 	m_can_disable_all_interrupts(cdev);
1138 	return IRQ_HANDLED;
1139 }
1140 
1141 static const struct can_bittiming_const m_can_bittiming_const_30X = {
1142 	.name = KBUILD_MODNAME,
1143 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
1144 	.tseg1_max = 64,
1145 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1146 	.tseg2_max = 16,
1147 	.sjw_max = 16,
1148 	.brp_min = 1,
1149 	.brp_max = 1024,
1150 	.brp_inc = 1,
1151 };
1152 
1153 static const struct can_bittiming_const m_can_data_bittiming_const_30X = {
1154 	.name = KBUILD_MODNAME,
1155 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
1156 	.tseg1_max = 16,
1157 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1158 	.tseg2_max = 8,
1159 	.sjw_max = 4,
1160 	.brp_min = 1,
1161 	.brp_max = 32,
1162 	.brp_inc = 1,
1163 };
1164 
1165 static const struct can_bittiming_const m_can_bittiming_const_31X = {
1166 	.name = KBUILD_MODNAME,
1167 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
1168 	.tseg1_max = 256,
1169 	.tseg2_min = 2,		/* Time segment 2 = phase_seg2 */
1170 	.tseg2_max = 128,
1171 	.sjw_max = 128,
1172 	.brp_min = 1,
1173 	.brp_max = 512,
1174 	.brp_inc = 1,
1175 };
1176 
1177 static const struct can_bittiming_const m_can_data_bittiming_const_31X = {
1178 	.name = KBUILD_MODNAME,
1179 	.tseg1_min = 1,		/* Time segment 1 = prop_seg + phase_seg1 */
1180 	.tseg1_max = 32,
1181 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1182 	.tseg2_max = 16,
1183 	.sjw_max = 16,
1184 	.brp_min = 1,
1185 	.brp_max = 32,
1186 	.brp_inc = 1,
1187 };
1188 
1189 static int m_can_set_bittiming(struct net_device *dev)
1190 {
1191 	struct m_can_classdev *cdev = netdev_priv(dev);
1192 	const struct can_bittiming *bt = &cdev->can.bittiming;
1193 	const struct can_bittiming *dbt = &cdev->can.data_bittiming;
1194 	u16 brp, sjw, tseg1, tseg2;
1195 	u32 reg_btp;
1196 
1197 	brp = bt->brp - 1;
1198 	sjw = bt->sjw - 1;
1199 	tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
1200 	tseg2 = bt->phase_seg2 - 1;
1201 	reg_btp = FIELD_PREP(NBTP_NBRP_MASK, brp) |
1202 		  FIELD_PREP(NBTP_NSJW_MASK, sjw) |
1203 		  FIELD_PREP(NBTP_NTSEG1_MASK, tseg1) |
1204 		  FIELD_PREP(NBTP_NTSEG2_MASK, tseg2);
1205 	m_can_write(cdev, M_CAN_NBTP, reg_btp);
1206 
1207 	if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
1208 		reg_btp = 0;
1209 		brp = dbt->brp - 1;
1210 		sjw = dbt->sjw - 1;
1211 		tseg1 = dbt->prop_seg + dbt->phase_seg1 - 1;
1212 		tseg2 = dbt->phase_seg2 - 1;
1213 
1214 		/* TDC is only needed for bitrates beyond 2.5 MBit/s.
1215 		 * This is mentioned in the "Bit Time Requirements for CAN FD"
1216 		 * paper presented at the International CAN Conference 2013
1217 		 */
1218 		if (dbt->bitrate > 2500000) {
1219 			u32 tdco, ssp;
1220 
1221 			/* Use the same value of secondary sampling point
1222 			 * as the data sampling point
1223 			 */
1224 			ssp = dbt->sample_point;
1225 
1226 			/* Equation based on Bosch's M_CAN User Manual's
1227 			 * Transmitter Delay Compensation Section
1228 			 */
1229 			tdco = (cdev->can.clock.freq / 1000) *
1230 				ssp / dbt->bitrate;
1231 
1232 			/* Max valid TDCO value is 127 */
1233 			if (tdco > 127) {
1234 				netdev_warn(dev, "TDCO value of %u is beyond maximum. Using maximum possible value\n",
1235 					    tdco);
1236 				tdco = 127;
1237 			}
1238 
1239 			reg_btp |= DBTP_TDC;
1240 			m_can_write(cdev, M_CAN_TDCR,
1241 				    FIELD_PREP(TDCR_TDCO_MASK, tdco));
1242 		}
1243 
1244 		reg_btp |= FIELD_PREP(DBTP_DBRP_MASK, brp) |
1245 			FIELD_PREP(DBTP_DSJW_MASK, sjw) |
1246 			FIELD_PREP(DBTP_DTSEG1_MASK, tseg1) |
1247 			FIELD_PREP(DBTP_DTSEG2_MASK, tseg2);
1248 
1249 		m_can_write(cdev, M_CAN_DBTP, reg_btp);
1250 	}
1251 
1252 	return 0;
1253 }
1254 
1255 /* Configure M_CAN chip:
1256  * - set rx buffer/fifo element size
1257  * - configure rx fifo
1258  * - accept non-matching frame into fifo 0
1259  * - configure tx buffer
1260  *		- >= v3.1.x: TX FIFO is used
1261  * - configure mode
1262  * - setup bittiming
1263  * - configure timestamp generation
1264  */
1265 static int m_can_chip_config(struct net_device *dev)
1266 {
1267 	struct m_can_classdev *cdev = netdev_priv(dev);
1268 	u32 interrupts = IR_ALL_INT;
1269 	u32 cccr, test;
1270 	int err;
1271 
1272 	err = m_can_init_ram(cdev);
1273 	if (err) {
1274 		dev_err(cdev->dev, "Message RAM configuration failed\n");
1275 		return err;
1276 	}
1277 
1278 	/* Disable unused interrupts */
1279 	interrupts &= ~(IR_ARA | IR_ELO | IR_DRX | IR_TEFF | IR_TEFW | IR_TFE |
1280 			IR_TCF | IR_HPM | IR_RF1F | IR_RF1W | IR_RF1N |
1281 			IR_RF0F | IR_RF0W);
1282 
1283 	m_can_config_endisable(cdev, true);
1284 
1285 	/* RX Buffer/FIFO Element Size 64 bytes data field */
1286 	m_can_write(cdev, M_CAN_RXESC,
1287 		    FIELD_PREP(RXESC_RBDS_MASK, RXESC_64B) |
1288 		    FIELD_PREP(RXESC_F1DS_MASK, RXESC_64B) |
1289 		    FIELD_PREP(RXESC_F0DS_MASK, RXESC_64B));
1290 
1291 	/* Accept Non-matching Frames Into FIFO 0 */
1292 	m_can_write(cdev, M_CAN_GFC, 0x0);
1293 
1294 	if (cdev->version == 30) {
1295 		/* only support one Tx Buffer currently */
1296 		m_can_write(cdev, M_CAN_TXBC, FIELD_PREP(TXBC_NDTB_MASK, 1) |
1297 			    cdev->mcfg[MRAM_TXB].off);
1298 	} else {
1299 		/* TX FIFO is used for newer IP Core versions */
1300 		m_can_write(cdev, M_CAN_TXBC,
1301 			    FIELD_PREP(TXBC_TFQS_MASK,
1302 				       cdev->mcfg[MRAM_TXB].num) |
1303 			    cdev->mcfg[MRAM_TXB].off);
1304 	}
1305 
1306 	/* support 64 bytes payload */
1307 	m_can_write(cdev, M_CAN_TXESC,
1308 		    FIELD_PREP(TXESC_TBDS_MASK, TXESC_TBDS_64B));
1309 
1310 	/* TX Event FIFO */
1311 	if (cdev->version == 30) {
1312 		m_can_write(cdev, M_CAN_TXEFC,
1313 			    FIELD_PREP(TXEFC_EFS_MASK, 1) |
1314 			    cdev->mcfg[MRAM_TXE].off);
1315 	} else {
1316 		/* Full TX Event FIFO is used */
1317 		m_can_write(cdev, M_CAN_TXEFC,
1318 			    FIELD_PREP(TXEFC_EFS_MASK,
1319 				       cdev->mcfg[MRAM_TXE].num) |
1320 			    cdev->mcfg[MRAM_TXE].off);
1321 	}
1322 
1323 	/* rx fifo configuration, blocking mode, fifo size 1 */
1324 	m_can_write(cdev, M_CAN_RXF0C,
1325 		    FIELD_PREP(RXFC_FS_MASK, cdev->mcfg[MRAM_RXF0].num) |
1326 		    cdev->mcfg[MRAM_RXF0].off);
1327 
1328 	m_can_write(cdev, M_CAN_RXF1C,
1329 		    FIELD_PREP(RXFC_FS_MASK, cdev->mcfg[MRAM_RXF1].num) |
1330 		    cdev->mcfg[MRAM_RXF1].off);
1331 
1332 	cccr = m_can_read(cdev, M_CAN_CCCR);
1333 	test = m_can_read(cdev, M_CAN_TEST);
1334 	test &= ~TEST_LBCK;
1335 	if (cdev->version == 30) {
1336 		/* Version 3.0.x */
1337 
1338 		cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_DAR |
1339 			  FIELD_PREP(CCCR_CMR_MASK, FIELD_MAX(CCCR_CMR_MASK)) |
1340 			  FIELD_PREP(CCCR_CME_MASK, FIELD_MAX(CCCR_CME_MASK)));
1341 
1342 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD)
1343 			cccr |= FIELD_PREP(CCCR_CME_MASK, CCCR_CME_CANFD_BRS);
1344 
1345 	} else {
1346 		/* Version 3.1.x or 3.2.x */
1347 		cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE |
1348 			  CCCR_NISO | CCCR_DAR);
1349 
1350 		/* Only 3.2.x has NISO Bit implemented */
1351 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
1352 			cccr |= CCCR_NISO;
1353 
1354 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD)
1355 			cccr |= (CCCR_BRSE | CCCR_FDOE);
1356 	}
1357 
1358 	/* Loopback Mode */
1359 	if (cdev->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
1360 		cccr |= CCCR_TEST | CCCR_MON;
1361 		test |= TEST_LBCK;
1362 	}
1363 
1364 	/* Enable Monitoring (all versions) */
1365 	if (cdev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
1366 		cccr |= CCCR_MON;
1367 
1368 	/* Disable Auto Retransmission (all versions) */
1369 	if (cdev->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
1370 		cccr |= CCCR_DAR;
1371 
1372 	/* Write config */
1373 	m_can_write(cdev, M_CAN_CCCR, cccr);
1374 	m_can_write(cdev, M_CAN_TEST, test);
1375 
1376 	/* Enable interrupts */
1377 	if (!(cdev->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)) {
1378 		if (cdev->version == 30)
1379 			interrupts &= ~(IR_ERR_LEC_30X);
1380 		else
1381 			interrupts &= ~(IR_ERR_LEC_31X);
1382 	}
1383 	m_can_write(cdev, M_CAN_IE, interrupts);
1384 
1385 	/* route all interrupts to INT0 */
1386 	m_can_write(cdev, M_CAN_ILS, ILS_ALL_INT0);
1387 
1388 	/* set bittiming params */
1389 	m_can_set_bittiming(dev);
1390 
1391 	/* enable internal timestamp generation, with a prescaler of 16. The
1392 	 * prescaler is applied to the nominal bit timing
1393 	 */
1394 	m_can_write(cdev, M_CAN_TSCC,
1395 		    FIELD_PREP(TSCC_TCP_MASK, 0xf) |
1396 		    FIELD_PREP(TSCC_TSS_MASK, TSCC_TSS_INTERNAL));
1397 
1398 	m_can_config_endisable(cdev, false);
1399 
1400 	if (cdev->ops->init)
1401 		cdev->ops->init(cdev);
1402 
1403 	return 0;
1404 }
1405 
1406 static int m_can_start(struct net_device *dev)
1407 {
1408 	struct m_can_classdev *cdev = netdev_priv(dev);
1409 	int ret;
1410 
1411 	/* basic m_can configuration */
1412 	ret = m_can_chip_config(dev);
1413 	if (ret)
1414 		return ret;
1415 
1416 	cdev->can.state = CAN_STATE_ERROR_ACTIVE;
1417 
1418 	m_can_enable_all_interrupts(cdev);
1419 
1420 	if (!dev->irq) {
1421 		dev_dbg(cdev->dev, "Start hrtimer\n");
1422 		hrtimer_start(&cdev->hrtimer, ms_to_ktime(HRTIMER_POLL_INTERVAL_MS),
1423 			      HRTIMER_MODE_REL_PINNED);
1424 	}
1425 
1426 	return 0;
1427 }
1428 
1429 static int m_can_set_mode(struct net_device *dev, enum can_mode mode)
1430 {
1431 	switch (mode) {
1432 	case CAN_MODE_START:
1433 		m_can_clean(dev);
1434 		m_can_start(dev);
1435 		netif_wake_queue(dev);
1436 		break;
1437 	default:
1438 		return -EOPNOTSUPP;
1439 	}
1440 
1441 	return 0;
1442 }
1443 
1444 /* Checks core release number of M_CAN
1445  * returns 0 if an unsupported device is detected
1446  * else it returns the release and step coded as:
1447  * return value = 10 * <release> + 1 * <step>
1448  */
1449 static int m_can_check_core_release(struct m_can_classdev *cdev)
1450 {
1451 	u32 crel_reg;
1452 	u8 rel;
1453 	u8 step;
1454 	int res;
1455 
1456 	/* Read Core Release Version and split into version number
1457 	 * Example: Version 3.2.1 => rel = 3; step = 2; substep = 1;
1458 	 */
1459 	crel_reg = m_can_read(cdev, M_CAN_CREL);
1460 	rel = (u8)FIELD_GET(CREL_REL_MASK, crel_reg);
1461 	step = (u8)FIELD_GET(CREL_STEP_MASK, crel_reg);
1462 
1463 	if (rel == 3) {
1464 		/* M_CAN v3.x.y: create return value */
1465 		res = 30 + step;
1466 	} else {
1467 		/* Unsupported M_CAN version */
1468 		res = 0;
1469 	}
1470 
1471 	return res;
1472 }
1473 
1474 /* Selectable Non ISO support only in version 3.2.x
1475  * This function checks if the bit is writable.
1476  */
1477 static bool m_can_niso_supported(struct m_can_classdev *cdev)
1478 {
1479 	u32 cccr_reg, cccr_poll = 0;
1480 	int niso_timeout = -ETIMEDOUT;
1481 	int i;
1482 
1483 	m_can_config_endisable(cdev, true);
1484 	cccr_reg = m_can_read(cdev, M_CAN_CCCR);
1485 	cccr_reg |= CCCR_NISO;
1486 	m_can_write(cdev, M_CAN_CCCR, cccr_reg);
1487 
1488 	for (i = 0; i <= 10; i++) {
1489 		cccr_poll = m_can_read(cdev, M_CAN_CCCR);
1490 		if (cccr_poll == cccr_reg) {
1491 			niso_timeout = 0;
1492 			break;
1493 		}
1494 
1495 		usleep_range(1, 5);
1496 	}
1497 
1498 	/* Clear NISO */
1499 	cccr_reg &= ~(CCCR_NISO);
1500 	m_can_write(cdev, M_CAN_CCCR, cccr_reg);
1501 
1502 	m_can_config_endisable(cdev, false);
1503 
1504 	/* return false if time out (-ETIMEDOUT), else return true */
1505 	return !niso_timeout;
1506 }
1507 
1508 static int m_can_dev_setup(struct m_can_classdev *cdev)
1509 {
1510 	struct net_device *dev = cdev->net;
1511 	int m_can_version, err;
1512 
1513 	m_can_version = m_can_check_core_release(cdev);
1514 	/* return if unsupported version */
1515 	if (!m_can_version) {
1516 		dev_err(cdev->dev, "Unsupported version number: %2d",
1517 			m_can_version);
1518 		return -EINVAL;
1519 	}
1520 
1521 	if (!cdev->is_peripheral)
1522 		netif_napi_add(dev, &cdev->napi, m_can_poll);
1523 
1524 	/* Shared properties of all M_CAN versions */
1525 	cdev->version = m_can_version;
1526 	cdev->can.do_set_mode = m_can_set_mode;
1527 	cdev->can.do_get_berr_counter = m_can_get_berr_counter;
1528 
1529 	/* Set M_CAN supported operations */
1530 	cdev->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
1531 		CAN_CTRLMODE_LISTENONLY |
1532 		CAN_CTRLMODE_BERR_REPORTING |
1533 		CAN_CTRLMODE_FD |
1534 		CAN_CTRLMODE_ONE_SHOT;
1535 
1536 	/* Set properties depending on M_CAN version */
1537 	switch (cdev->version) {
1538 	case 30:
1539 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.0.x */
1540 		err = can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
1541 		if (err)
1542 			return err;
1543 		cdev->can.bittiming_const = &m_can_bittiming_const_30X;
1544 		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_30X;
1545 		break;
1546 	case 31:
1547 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.1.x */
1548 		err = can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
1549 		if (err)
1550 			return err;
1551 		cdev->can.bittiming_const = &m_can_bittiming_const_31X;
1552 		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
1553 		break;
1554 	case 32:
1555 	case 33:
1556 		/* Support both MCAN version v3.2.x and v3.3.0 */
1557 		cdev->can.bittiming_const = &m_can_bittiming_const_31X;
1558 		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
1559 
1560 		cdev->can.ctrlmode_supported |=
1561 			(m_can_niso_supported(cdev) ?
1562 			 CAN_CTRLMODE_FD_NON_ISO : 0);
1563 		break;
1564 	default:
1565 		dev_err(cdev->dev, "Unsupported version number: %2d",
1566 			cdev->version);
1567 		return -EINVAL;
1568 	}
1569 
1570 	if (cdev->ops->init)
1571 		cdev->ops->init(cdev);
1572 
1573 	return 0;
1574 }
1575 
1576 static void m_can_stop(struct net_device *dev)
1577 {
1578 	struct m_can_classdev *cdev = netdev_priv(dev);
1579 
1580 	if (!dev->irq) {
1581 		dev_dbg(cdev->dev, "Stop hrtimer\n");
1582 		hrtimer_cancel(&cdev->hrtimer);
1583 	}
1584 
1585 	/* disable all interrupts */
1586 	m_can_disable_all_interrupts(cdev);
1587 
1588 	/* Set init mode to disengage from the network */
1589 	m_can_config_endisable(cdev, true);
1590 
1591 	/* set the state as STOPPED */
1592 	cdev->can.state = CAN_STATE_STOPPED;
1593 }
1594 
1595 static int m_can_close(struct net_device *dev)
1596 {
1597 	struct m_can_classdev *cdev = netdev_priv(dev);
1598 
1599 	netif_stop_queue(dev);
1600 
1601 	if (!cdev->is_peripheral)
1602 		napi_disable(&cdev->napi);
1603 
1604 	m_can_stop(dev);
1605 	m_can_clk_stop(cdev);
1606 	free_irq(dev->irq, dev);
1607 
1608 	if (cdev->is_peripheral) {
1609 		cdev->tx_skb = NULL;
1610 		destroy_workqueue(cdev->tx_wq);
1611 		cdev->tx_wq = NULL;
1612 		can_rx_offload_disable(&cdev->offload);
1613 	}
1614 
1615 	close_candev(dev);
1616 
1617 	phy_power_off(cdev->transceiver);
1618 
1619 	return 0;
1620 }
1621 
1622 static int m_can_next_echo_skb_occupied(struct net_device *dev, int putidx)
1623 {
1624 	struct m_can_classdev *cdev = netdev_priv(dev);
1625 	/*get wrap around for loopback skb index */
1626 	unsigned int wrap = cdev->can.echo_skb_max;
1627 	int next_idx;
1628 
1629 	/* calculate next index */
1630 	next_idx = (++putidx >= wrap ? 0 : putidx);
1631 
1632 	/* check if occupied */
1633 	return !!cdev->can.echo_skb[next_idx];
1634 }
1635 
1636 static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
1637 {
1638 	struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
1639 	struct net_device *dev = cdev->net;
1640 	struct sk_buff *skb = cdev->tx_skb;
1641 	struct id_and_dlc fifo_header;
1642 	u32 cccr, fdflags;
1643 	u32 txfqs;
1644 	int err;
1645 	int putidx;
1646 
1647 	cdev->tx_skb = NULL;
1648 
1649 	/* Generate ID field for TX buffer Element */
1650 	/* Common to all supported M_CAN versions */
1651 	if (cf->can_id & CAN_EFF_FLAG) {
1652 		fifo_header.id = cf->can_id & CAN_EFF_MASK;
1653 		fifo_header.id |= TX_BUF_XTD;
1654 	} else {
1655 		fifo_header.id = ((cf->can_id & CAN_SFF_MASK) << 18);
1656 	}
1657 
1658 	if (cf->can_id & CAN_RTR_FLAG)
1659 		fifo_header.id |= TX_BUF_RTR;
1660 
1661 	if (cdev->version == 30) {
1662 		netif_stop_queue(dev);
1663 
1664 		fifo_header.dlc = can_fd_len2dlc(cf->len) << 16;
1665 
1666 		/* Write the frame ID, DLC, and payload to the FIFO element. */
1667 		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_header, 2);
1668 		if (err)
1669 			goto out_fail;
1670 
1671 		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_DATA,
1672 				       cf->data, DIV_ROUND_UP(cf->len, 4));
1673 		if (err)
1674 			goto out_fail;
1675 
1676 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
1677 			cccr = m_can_read(cdev, M_CAN_CCCR);
1678 			cccr &= ~CCCR_CMR_MASK;
1679 			if (can_is_canfd_skb(skb)) {
1680 				if (cf->flags & CANFD_BRS)
1681 					cccr |= FIELD_PREP(CCCR_CMR_MASK,
1682 							   CCCR_CMR_CANFD_BRS);
1683 				else
1684 					cccr |= FIELD_PREP(CCCR_CMR_MASK,
1685 							   CCCR_CMR_CANFD);
1686 			} else {
1687 				cccr |= FIELD_PREP(CCCR_CMR_MASK, CCCR_CMR_CAN);
1688 			}
1689 			m_can_write(cdev, M_CAN_CCCR, cccr);
1690 		}
1691 		m_can_write(cdev, M_CAN_TXBTIE, 0x1);
1692 
1693 		can_put_echo_skb(skb, dev, 0, 0);
1694 
1695 		m_can_write(cdev, M_CAN_TXBAR, 0x1);
1696 		/* End of xmit function for version 3.0.x */
1697 	} else {
1698 		/* Transmit routine for version >= v3.1.x */
1699 
1700 		txfqs = m_can_read(cdev, M_CAN_TXFQS);
1701 
1702 		/* Check if FIFO full */
1703 		if (_m_can_tx_fifo_full(txfqs)) {
1704 			/* This shouldn't happen */
1705 			netif_stop_queue(dev);
1706 			netdev_warn(dev,
1707 				    "TX queue active although FIFO is full.");
1708 
1709 			if (cdev->is_peripheral) {
1710 				kfree_skb(skb);
1711 				dev->stats.tx_dropped++;
1712 				return NETDEV_TX_OK;
1713 			} else {
1714 				return NETDEV_TX_BUSY;
1715 			}
1716 		}
1717 
1718 		/* get put index for frame */
1719 		putidx = FIELD_GET(TXFQS_TFQPI_MASK, txfqs);
1720 
1721 		/* Construct DLC Field, with CAN-FD configuration.
1722 		 * Use the put index of the fifo as the message marker,
1723 		 * used in the TX interrupt for sending the correct echo frame.
1724 		 */
1725 
1726 		/* get CAN FD configuration of frame */
1727 		fdflags = 0;
1728 		if (can_is_canfd_skb(skb)) {
1729 			fdflags |= TX_BUF_FDF;
1730 			if (cf->flags & CANFD_BRS)
1731 				fdflags |= TX_BUF_BRS;
1732 		}
1733 
1734 		fifo_header.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) |
1735 			FIELD_PREP(TX_BUF_DLC_MASK, can_fd_len2dlc(cf->len)) |
1736 			fdflags | TX_BUF_EFC;
1737 		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, &fifo_header, 2);
1738 		if (err)
1739 			goto out_fail;
1740 
1741 		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA,
1742 				       cf->data, DIV_ROUND_UP(cf->len, 4));
1743 		if (err)
1744 			goto out_fail;
1745 
1746 		/* Push loopback echo.
1747 		 * Will be looped back on TX interrupt based on message marker
1748 		 */
1749 		can_put_echo_skb(skb, dev, putidx, 0);
1750 
1751 		/* Enable TX FIFO element to start transfer  */
1752 		m_can_write(cdev, M_CAN_TXBAR, (1 << putidx));
1753 
1754 		/* stop network queue if fifo full */
1755 		if (m_can_tx_fifo_full(cdev) ||
1756 		    m_can_next_echo_skb_occupied(dev, putidx))
1757 			netif_stop_queue(dev);
1758 	}
1759 
1760 	return NETDEV_TX_OK;
1761 
1762 out_fail:
1763 	netdev_err(dev, "FIFO write returned %d\n", err);
1764 	m_can_disable_all_interrupts(cdev);
1765 	return NETDEV_TX_BUSY;
1766 }
1767 
1768 static void m_can_tx_work_queue(struct work_struct *ws)
1769 {
1770 	struct m_can_classdev *cdev = container_of(ws, struct m_can_classdev,
1771 						   tx_work);
1772 
1773 	m_can_tx_handler(cdev);
1774 }
1775 
1776 static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
1777 				    struct net_device *dev)
1778 {
1779 	struct m_can_classdev *cdev = netdev_priv(dev);
1780 
1781 	if (can_dev_dropped_skb(dev, skb))
1782 		return NETDEV_TX_OK;
1783 
1784 	if (cdev->is_peripheral) {
1785 		if (cdev->tx_skb) {
1786 			netdev_err(dev, "hard_xmit called while tx busy\n");
1787 			return NETDEV_TX_BUSY;
1788 		}
1789 
1790 		if (cdev->can.state == CAN_STATE_BUS_OFF) {
1791 			m_can_clean(dev);
1792 		} else {
1793 			/* Need to stop the queue to avoid numerous requests
1794 			 * from being sent.  Suggested improvement is to create
1795 			 * a queueing mechanism that will queue the skbs and
1796 			 * process them in order.
1797 			 */
1798 			cdev->tx_skb = skb;
1799 			netif_stop_queue(cdev->net);
1800 			queue_work(cdev->tx_wq, &cdev->tx_work);
1801 		}
1802 	} else {
1803 		cdev->tx_skb = skb;
1804 		return m_can_tx_handler(cdev);
1805 	}
1806 
1807 	return NETDEV_TX_OK;
1808 }
1809 
1810 static enum hrtimer_restart hrtimer_callback(struct hrtimer *timer)
1811 {
1812 	struct m_can_classdev *cdev = container_of(timer, struct
1813 						   m_can_classdev, hrtimer);
1814 
1815 	m_can_isr(0, cdev->net);
1816 
1817 	hrtimer_forward_now(timer, ms_to_ktime(HRTIMER_POLL_INTERVAL_MS));
1818 
1819 	return HRTIMER_RESTART;
1820 }
1821 
1822 static int m_can_open(struct net_device *dev)
1823 {
1824 	struct m_can_classdev *cdev = netdev_priv(dev);
1825 	int err;
1826 
1827 	err = phy_power_on(cdev->transceiver);
1828 	if (err)
1829 		return err;
1830 
1831 	err = m_can_clk_start(cdev);
1832 	if (err)
1833 		goto out_phy_power_off;
1834 
1835 	/* open the can device */
1836 	err = open_candev(dev);
1837 	if (err) {
1838 		netdev_err(dev, "failed to open can device\n");
1839 		goto exit_disable_clks;
1840 	}
1841 
1842 	if (cdev->is_peripheral)
1843 		can_rx_offload_enable(&cdev->offload);
1844 
1845 	/* register interrupt handler */
1846 	if (cdev->is_peripheral) {
1847 		cdev->tx_skb = NULL;
1848 		cdev->tx_wq = alloc_workqueue("mcan_wq",
1849 					      WQ_FREEZABLE | WQ_MEM_RECLAIM, 0);
1850 		if (!cdev->tx_wq) {
1851 			err = -ENOMEM;
1852 			goto out_wq_fail;
1853 		}
1854 
1855 		INIT_WORK(&cdev->tx_work, m_can_tx_work_queue);
1856 
1857 		err = request_threaded_irq(dev->irq, NULL, m_can_isr,
1858 					   IRQF_ONESHOT,
1859 					   dev->name, dev);
1860 	} else if (dev->irq) {
1861 		err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
1862 				  dev);
1863 	}
1864 
1865 	if (err < 0) {
1866 		netdev_err(dev, "failed to request interrupt\n");
1867 		goto exit_irq_fail;
1868 	}
1869 
1870 	/* start the m_can controller */
1871 	err = m_can_start(dev);
1872 	if (err)
1873 		goto exit_irq_fail;
1874 
1875 	if (!cdev->is_peripheral)
1876 		napi_enable(&cdev->napi);
1877 
1878 	netif_start_queue(dev);
1879 
1880 	return 0;
1881 
1882 exit_irq_fail:
1883 	if (cdev->is_peripheral)
1884 		destroy_workqueue(cdev->tx_wq);
1885 out_wq_fail:
1886 	if (cdev->is_peripheral)
1887 		can_rx_offload_disable(&cdev->offload);
1888 	close_candev(dev);
1889 exit_disable_clks:
1890 	m_can_clk_stop(cdev);
1891 out_phy_power_off:
1892 	phy_power_off(cdev->transceiver);
1893 	return err;
1894 }
1895 
1896 static const struct net_device_ops m_can_netdev_ops = {
1897 	.ndo_open = m_can_open,
1898 	.ndo_stop = m_can_close,
1899 	.ndo_start_xmit = m_can_start_xmit,
1900 	.ndo_change_mtu = can_change_mtu,
1901 };
1902 
1903 static const struct ethtool_ops m_can_ethtool_ops = {
1904 	.get_ts_info = ethtool_op_get_ts_info,
1905 };
1906 
1907 static int register_m_can_dev(struct net_device *dev)
1908 {
1909 	dev->flags |= IFF_ECHO;	/* we support local echo */
1910 	dev->netdev_ops = &m_can_netdev_ops;
1911 	dev->ethtool_ops = &m_can_ethtool_ops;
1912 
1913 	return register_candev(dev);
1914 }
1915 
1916 int m_can_check_mram_cfg(struct m_can_classdev *cdev, u32 mram_max_size)
1917 {
1918 	u32 total_size;
1919 
1920 	total_size = cdev->mcfg[MRAM_TXB].off - cdev->mcfg[MRAM_SIDF].off +
1921 			cdev->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE;
1922 	if (total_size > mram_max_size) {
1923 		dev_err(cdev->dev, "Total size of mram config(%u) exceeds mram(%u)\n",
1924 			total_size, mram_max_size);
1925 		return -EINVAL;
1926 	}
1927 
1928 	return 0;
1929 }
1930 EXPORT_SYMBOL_GPL(m_can_check_mram_cfg);
1931 
1932 static void m_can_of_parse_mram(struct m_can_classdev *cdev,
1933 				const u32 *mram_config_vals)
1934 {
1935 	cdev->mcfg[MRAM_SIDF].off = mram_config_vals[0];
1936 	cdev->mcfg[MRAM_SIDF].num = mram_config_vals[1];
1937 	cdev->mcfg[MRAM_XIDF].off = cdev->mcfg[MRAM_SIDF].off +
1938 		cdev->mcfg[MRAM_SIDF].num * SIDF_ELEMENT_SIZE;
1939 	cdev->mcfg[MRAM_XIDF].num = mram_config_vals[2];
1940 	cdev->mcfg[MRAM_RXF0].off = cdev->mcfg[MRAM_XIDF].off +
1941 		cdev->mcfg[MRAM_XIDF].num * XIDF_ELEMENT_SIZE;
1942 	cdev->mcfg[MRAM_RXF0].num = mram_config_vals[3] &
1943 		FIELD_MAX(RXFC_FS_MASK);
1944 	cdev->mcfg[MRAM_RXF1].off = cdev->mcfg[MRAM_RXF0].off +
1945 		cdev->mcfg[MRAM_RXF0].num * RXF0_ELEMENT_SIZE;
1946 	cdev->mcfg[MRAM_RXF1].num = mram_config_vals[4] &
1947 		FIELD_MAX(RXFC_FS_MASK);
1948 	cdev->mcfg[MRAM_RXB].off = cdev->mcfg[MRAM_RXF1].off +
1949 		cdev->mcfg[MRAM_RXF1].num * RXF1_ELEMENT_SIZE;
1950 	cdev->mcfg[MRAM_RXB].num = mram_config_vals[5];
1951 	cdev->mcfg[MRAM_TXE].off = cdev->mcfg[MRAM_RXB].off +
1952 		cdev->mcfg[MRAM_RXB].num * RXB_ELEMENT_SIZE;
1953 	cdev->mcfg[MRAM_TXE].num = mram_config_vals[6];
1954 	cdev->mcfg[MRAM_TXB].off = cdev->mcfg[MRAM_TXE].off +
1955 		cdev->mcfg[MRAM_TXE].num * TXE_ELEMENT_SIZE;
1956 	cdev->mcfg[MRAM_TXB].num = mram_config_vals[7] &
1957 		FIELD_MAX(TXBC_NDTB_MASK);
1958 
1959 	dev_dbg(cdev->dev,
1960 		"sidf 0x%x %d xidf 0x%x %d rxf0 0x%x %d rxf1 0x%x %d rxb 0x%x %d txe 0x%x %d txb 0x%x %d\n",
1961 		cdev->mcfg[MRAM_SIDF].off, cdev->mcfg[MRAM_SIDF].num,
1962 		cdev->mcfg[MRAM_XIDF].off, cdev->mcfg[MRAM_XIDF].num,
1963 		cdev->mcfg[MRAM_RXF0].off, cdev->mcfg[MRAM_RXF0].num,
1964 		cdev->mcfg[MRAM_RXF1].off, cdev->mcfg[MRAM_RXF1].num,
1965 		cdev->mcfg[MRAM_RXB].off, cdev->mcfg[MRAM_RXB].num,
1966 		cdev->mcfg[MRAM_TXE].off, cdev->mcfg[MRAM_TXE].num,
1967 		cdev->mcfg[MRAM_TXB].off, cdev->mcfg[MRAM_TXB].num);
1968 }
1969 
1970 int m_can_init_ram(struct m_can_classdev *cdev)
1971 {
1972 	int end, i, start;
1973 	int err = 0;
1974 
1975 	/* initialize the entire Message RAM in use to avoid possible
1976 	 * ECC/parity checksum errors when reading an uninitialized buffer
1977 	 */
1978 	start = cdev->mcfg[MRAM_SIDF].off;
1979 	end = cdev->mcfg[MRAM_TXB].off +
1980 		cdev->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE;
1981 
1982 	for (i = start; i < end; i += 4) {
1983 		err = m_can_fifo_write_no_off(cdev, i, 0x0);
1984 		if (err)
1985 			break;
1986 	}
1987 
1988 	return err;
1989 }
1990 EXPORT_SYMBOL_GPL(m_can_init_ram);
1991 
1992 int m_can_class_get_clocks(struct m_can_classdev *cdev)
1993 {
1994 	int ret = 0;
1995 
1996 	cdev->hclk = devm_clk_get(cdev->dev, "hclk");
1997 	cdev->cclk = devm_clk_get(cdev->dev, "cclk");
1998 
1999 	if (IS_ERR(cdev->hclk) || IS_ERR(cdev->cclk)) {
2000 		dev_err(cdev->dev, "no clock found\n");
2001 		ret = -ENODEV;
2002 	}
2003 
2004 	return ret;
2005 }
2006 EXPORT_SYMBOL_GPL(m_can_class_get_clocks);
2007 
2008 struct m_can_classdev *m_can_class_allocate_dev(struct device *dev,
2009 						int sizeof_priv)
2010 {
2011 	struct m_can_classdev *class_dev = NULL;
2012 	u32 mram_config_vals[MRAM_CFG_LEN];
2013 	struct net_device *net_dev;
2014 	u32 tx_fifo_size;
2015 	int ret;
2016 
2017 	ret = fwnode_property_read_u32_array(dev_fwnode(dev),
2018 					     "bosch,mram-cfg",
2019 					     mram_config_vals,
2020 					     sizeof(mram_config_vals) / 4);
2021 	if (ret) {
2022 		dev_err(dev, "Could not get Message RAM configuration.");
2023 		goto out;
2024 	}
2025 
2026 	/* Get TX FIFO size
2027 	 * Defines the total amount of echo buffers for loopback
2028 	 */
2029 	tx_fifo_size = mram_config_vals[7];
2030 
2031 	/* allocate the m_can device */
2032 	net_dev = alloc_candev(sizeof_priv, tx_fifo_size);
2033 	if (!net_dev) {
2034 		dev_err(dev, "Failed to allocate CAN device");
2035 		goto out;
2036 	}
2037 
2038 	class_dev = netdev_priv(net_dev);
2039 	class_dev->net = net_dev;
2040 	class_dev->dev = dev;
2041 	SET_NETDEV_DEV(net_dev, dev);
2042 
2043 	m_can_of_parse_mram(class_dev, mram_config_vals);
2044 out:
2045 	return class_dev;
2046 }
2047 EXPORT_SYMBOL_GPL(m_can_class_allocate_dev);
2048 
2049 void m_can_class_free_dev(struct net_device *net)
2050 {
2051 	free_candev(net);
2052 }
2053 EXPORT_SYMBOL_GPL(m_can_class_free_dev);
2054 
2055 int m_can_class_register(struct m_can_classdev *cdev)
2056 {
2057 	int ret;
2058 
2059 	if (cdev->pm_clock_support) {
2060 		ret = m_can_clk_start(cdev);
2061 		if (ret)
2062 			return ret;
2063 	}
2064 
2065 	if (cdev->is_peripheral) {
2066 		ret = can_rx_offload_add_manual(cdev->net, &cdev->offload,
2067 						NAPI_POLL_WEIGHT);
2068 		if (ret)
2069 			goto clk_disable;
2070 	}
2071 
2072 	if (!cdev->net->irq)
2073 		cdev->hrtimer.function = &hrtimer_callback;
2074 
2075 	ret = m_can_dev_setup(cdev);
2076 	if (ret)
2077 		goto rx_offload_del;
2078 
2079 	ret = register_m_can_dev(cdev->net);
2080 	if (ret) {
2081 		dev_err(cdev->dev, "registering %s failed (err=%d)\n",
2082 			cdev->net->name, ret);
2083 		goto rx_offload_del;
2084 	}
2085 
2086 	of_can_transceiver(cdev->net);
2087 
2088 	dev_info(cdev->dev, "%s device registered (irq=%d, version=%d)\n",
2089 		 KBUILD_MODNAME, cdev->net->irq, cdev->version);
2090 
2091 	/* Probe finished
2092 	 * Stop clocks. They will be reactivated once the M_CAN device is opened
2093 	 */
2094 	m_can_clk_stop(cdev);
2095 
2096 	return 0;
2097 
2098 rx_offload_del:
2099 	if (cdev->is_peripheral)
2100 		can_rx_offload_del(&cdev->offload);
2101 clk_disable:
2102 	m_can_clk_stop(cdev);
2103 
2104 	return ret;
2105 }
2106 EXPORT_SYMBOL_GPL(m_can_class_register);
2107 
2108 void m_can_class_unregister(struct m_can_classdev *cdev)
2109 {
2110 	if (cdev->is_peripheral)
2111 		can_rx_offload_del(&cdev->offload);
2112 	unregister_candev(cdev->net);
2113 }
2114 EXPORT_SYMBOL_GPL(m_can_class_unregister);
2115 
2116 int m_can_class_suspend(struct device *dev)
2117 {
2118 	struct m_can_classdev *cdev = dev_get_drvdata(dev);
2119 	struct net_device *ndev = cdev->net;
2120 
2121 	if (netif_running(ndev)) {
2122 		netif_stop_queue(ndev);
2123 		netif_device_detach(ndev);
2124 		m_can_stop(ndev);
2125 		m_can_clk_stop(cdev);
2126 	}
2127 
2128 	pinctrl_pm_select_sleep_state(dev);
2129 
2130 	cdev->can.state = CAN_STATE_SLEEPING;
2131 
2132 	return 0;
2133 }
2134 EXPORT_SYMBOL_GPL(m_can_class_suspend);
2135 
2136 int m_can_class_resume(struct device *dev)
2137 {
2138 	struct m_can_classdev *cdev = dev_get_drvdata(dev);
2139 	struct net_device *ndev = cdev->net;
2140 
2141 	pinctrl_pm_select_default_state(dev);
2142 
2143 	cdev->can.state = CAN_STATE_ERROR_ACTIVE;
2144 
2145 	if (netif_running(ndev)) {
2146 		int ret;
2147 
2148 		ret = m_can_clk_start(cdev);
2149 		if (ret)
2150 			return ret;
2151 		ret  = m_can_start(ndev);
2152 		if (ret) {
2153 			m_can_clk_stop(cdev);
2154 
2155 			return ret;
2156 		}
2157 
2158 		netif_device_attach(ndev);
2159 		netif_start_queue(ndev);
2160 	}
2161 
2162 	return 0;
2163 }
2164 EXPORT_SYMBOL_GPL(m_can_class_resume);
2165 
2166 MODULE_AUTHOR("Dong Aisheng <b29396@freescale.com>");
2167 MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
2168 MODULE_LICENSE("GPL v2");
2169 MODULE_DESCRIPTION("CAN bus driver for Bosch M_CAN controller");
2170