xref: /openbmc/linux/drivers/net/can/m_can/m_can.c (revision e8ec0493)
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  * http://www.bosch-semiconductors.de/media/pdf_1/ipmodules_1/m_can/
9  * mcan_users_manual_v302.pdf
10  */
11 
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/netdevice.h>
17 #include <linux/of.h>
18 #include <linux/of_device.h>
19 #include <linux/platform_device.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/iopoll.h>
22 #include <linux/can/dev.h>
23 #include <linux/pinctrl/consumer.h>
24 
25 #include "m_can.h"
26 
27 /* registers definition */
28 enum m_can_reg {
29 	M_CAN_CREL	= 0x0,
30 	M_CAN_ENDN	= 0x4,
31 	M_CAN_CUST	= 0x8,
32 	M_CAN_DBTP	= 0xc,
33 	M_CAN_TEST	= 0x10,
34 	M_CAN_RWD	= 0x14,
35 	M_CAN_CCCR	= 0x18,
36 	M_CAN_NBTP	= 0x1c,
37 	M_CAN_TSCC	= 0x20,
38 	M_CAN_TSCV	= 0x24,
39 	M_CAN_TOCC	= 0x28,
40 	M_CAN_TOCV	= 0x2c,
41 	M_CAN_ECR	= 0x40,
42 	M_CAN_PSR	= 0x44,
43 /* TDCR Register only available for version >=3.1.x */
44 	M_CAN_TDCR	= 0x48,
45 	M_CAN_IR	= 0x50,
46 	M_CAN_IE	= 0x54,
47 	M_CAN_ILS	= 0x58,
48 	M_CAN_ILE	= 0x5c,
49 	M_CAN_GFC	= 0x80,
50 	M_CAN_SIDFC	= 0x84,
51 	M_CAN_XIDFC	= 0x88,
52 	M_CAN_XIDAM	= 0x90,
53 	M_CAN_HPMS	= 0x94,
54 	M_CAN_NDAT1	= 0x98,
55 	M_CAN_NDAT2	= 0x9c,
56 	M_CAN_RXF0C	= 0xa0,
57 	M_CAN_RXF0S	= 0xa4,
58 	M_CAN_RXF0A	= 0xa8,
59 	M_CAN_RXBC	= 0xac,
60 	M_CAN_RXF1C	= 0xb0,
61 	M_CAN_RXF1S	= 0xb4,
62 	M_CAN_RXF1A	= 0xb8,
63 	M_CAN_RXESC	= 0xbc,
64 	M_CAN_TXBC	= 0xc0,
65 	M_CAN_TXFQS	= 0xc4,
66 	M_CAN_TXESC	= 0xc8,
67 	M_CAN_TXBRP	= 0xcc,
68 	M_CAN_TXBAR	= 0xd0,
69 	M_CAN_TXBCR	= 0xd4,
70 	M_CAN_TXBTO	= 0xd8,
71 	M_CAN_TXBCF	= 0xdc,
72 	M_CAN_TXBTIE	= 0xe0,
73 	M_CAN_TXBCIE	= 0xe4,
74 	M_CAN_TXEFC	= 0xf0,
75 	M_CAN_TXEFS	= 0xf4,
76 	M_CAN_TXEFA	= 0xf8,
77 };
78 
79 /* napi related */
80 #define M_CAN_NAPI_WEIGHT	64
81 
82 /* message ram configuration data length */
83 #define MRAM_CFG_LEN	8
84 
85 /* Core Release Register (CREL) */
86 #define CREL_REL_SHIFT		28
87 #define CREL_REL_MASK		(0xF << CREL_REL_SHIFT)
88 #define CREL_STEP_SHIFT		24
89 #define CREL_STEP_MASK		(0xF << CREL_STEP_SHIFT)
90 #define CREL_SUBSTEP_SHIFT	20
91 #define CREL_SUBSTEP_MASK	(0xF << CREL_SUBSTEP_SHIFT)
92 
93 /* Data Bit Timing & Prescaler Register (DBTP) */
94 #define DBTP_TDC		BIT(23)
95 #define DBTP_DBRP_SHIFT		16
96 #define DBTP_DBRP_MASK		(0x1f << DBTP_DBRP_SHIFT)
97 #define DBTP_DTSEG1_SHIFT	8
98 #define DBTP_DTSEG1_MASK	(0x1f << DBTP_DTSEG1_SHIFT)
99 #define DBTP_DTSEG2_SHIFT	4
100 #define DBTP_DTSEG2_MASK	(0xf << DBTP_DTSEG2_SHIFT)
101 #define DBTP_DSJW_SHIFT		0
102 #define DBTP_DSJW_MASK		(0xf << DBTP_DSJW_SHIFT)
103 
104 /* Transmitter Delay Compensation Register (TDCR) */
105 #define TDCR_TDCO_SHIFT		8
106 #define TDCR_TDCO_MASK		(0x7F << TDCR_TDCO_SHIFT)
107 #define TDCR_TDCF_SHIFT		0
108 #define TDCR_TDCF_MASK		(0x7F << TDCR_TDCF_SHIFT)
109 
110 /* Test Register (TEST) */
111 #define TEST_LBCK		BIT(4)
112 
113 /* CC Control Register(CCCR) */
114 #define CCCR_CMR_MASK		0x3
115 #define CCCR_CMR_SHIFT		10
116 #define CCCR_CMR_CANFD		0x1
117 #define CCCR_CMR_CANFD_BRS	0x2
118 #define CCCR_CMR_CAN		0x3
119 #define CCCR_CME_MASK		0x3
120 #define CCCR_CME_SHIFT		8
121 #define CCCR_CME_CAN		0
122 #define CCCR_CME_CANFD		0x1
123 #define CCCR_CME_CANFD_BRS	0x2
124 #define CCCR_TXP		BIT(14)
125 #define CCCR_TEST		BIT(7)
126 #define CCCR_DAR		BIT(6)
127 #define CCCR_MON		BIT(5)
128 #define CCCR_CSR		BIT(4)
129 #define CCCR_CSA		BIT(3)
130 #define CCCR_ASM		BIT(2)
131 #define CCCR_CCE		BIT(1)
132 #define CCCR_INIT		BIT(0)
133 #define CCCR_CANFD		0x10
134 /* for version >=3.1.x */
135 #define CCCR_EFBI		BIT(13)
136 #define CCCR_PXHD		BIT(12)
137 #define CCCR_BRSE		BIT(9)
138 #define CCCR_FDOE		BIT(8)
139 /* only for version >=3.2.x */
140 #define CCCR_NISO		BIT(15)
141 
142 /* Nominal Bit Timing & Prescaler Register (NBTP) */
143 #define NBTP_NSJW_SHIFT		25
144 #define NBTP_NSJW_MASK		(0x7f << NBTP_NSJW_SHIFT)
145 #define NBTP_NBRP_SHIFT		16
146 #define NBTP_NBRP_MASK		(0x1ff << NBTP_NBRP_SHIFT)
147 #define NBTP_NTSEG1_SHIFT	8
148 #define NBTP_NTSEG1_MASK	(0xff << NBTP_NTSEG1_SHIFT)
149 #define NBTP_NTSEG2_SHIFT	0
150 #define NBTP_NTSEG2_MASK	(0x7f << NBTP_NTSEG2_SHIFT)
151 
152 /* Error Counter Register(ECR) */
153 #define ECR_RP			BIT(15)
154 #define ECR_REC_SHIFT		8
155 #define ECR_REC_MASK		(0x7f << ECR_REC_SHIFT)
156 #define ECR_TEC_SHIFT		0
157 #define ECR_TEC_MASK		0xff
158 
159 /* Protocol Status Register(PSR) */
160 #define PSR_BO		BIT(7)
161 #define PSR_EW		BIT(6)
162 #define PSR_EP		BIT(5)
163 #define PSR_LEC_MASK	0x7
164 
165 /* Interrupt Register(IR) */
166 #define IR_ALL_INT	0xffffffff
167 
168 /* Renamed bits for versions > 3.1.x */
169 #define IR_ARA		BIT(29)
170 #define IR_PED		BIT(28)
171 #define IR_PEA		BIT(27)
172 
173 /* Bits for version 3.0.x */
174 #define IR_STE		BIT(31)
175 #define IR_FOE		BIT(30)
176 #define IR_ACKE		BIT(29)
177 #define IR_BE		BIT(28)
178 #define IR_CRCE		BIT(27)
179 #define IR_WDI		BIT(26)
180 #define IR_BO		BIT(25)
181 #define IR_EW		BIT(24)
182 #define IR_EP		BIT(23)
183 #define IR_ELO		BIT(22)
184 #define IR_BEU		BIT(21)
185 #define IR_BEC		BIT(20)
186 #define IR_DRX		BIT(19)
187 #define IR_TOO		BIT(18)
188 #define IR_MRAF		BIT(17)
189 #define IR_TSW		BIT(16)
190 #define IR_TEFL		BIT(15)
191 #define IR_TEFF		BIT(14)
192 #define IR_TEFW		BIT(13)
193 #define IR_TEFN		BIT(12)
194 #define IR_TFE		BIT(11)
195 #define IR_TCF		BIT(10)
196 #define IR_TC		BIT(9)
197 #define IR_HPM		BIT(8)
198 #define IR_RF1L		BIT(7)
199 #define IR_RF1F		BIT(6)
200 #define IR_RF1W		BIT(5)
201 #define IR_RF1N		BIT(4)
202 #define IR_RF0L		BIT(3)
203 #define IR_RF0F		BIT(2)
204 #define IR_RF0W		BIT(1)
205 #define IR_RF0N		BIT(0)
206 #define IR_ERR_STATE	(IR_BO | IR_EW | IR_EP)
207 
208 /* Interrupts for version 3.0.x */
209 #define IR_ERR_LEC_30X	(IR_STE	| IR_FOE | IR_ACKE | IR_BE | IR_CRCE)
210 #define IR_ERR_BUS_30X	(IR_ERR_LEC_30X | IR_WDI | IR_ELO | IR_BEU | \
211 			 IR_BEC | IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | \
212 			 IR_RF1L | IR_RF0L)
213 #define IR_ERR_ALL_30X	(IR_ERR_STATE | IR_ERR_BUS_30X)
214 /* Interrupts for version >= 3.1.x */
215 #define IR_ERR_LEC_31X	(IR_PED | IR_PEA)
216 #define IR_ERR_BUS_31X      (IR_ERR_LEC_31X | IR_WDI | IR_ELO | IR_BEU | \
217 			 IR_BEC | IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | \
218 			 IR_RF1L | IR_RF0L)
219 #define IR_ERR_ALL_31X	(IR_ERR_STATE | IR_ERR_BUS_31X)
220 
221 /* Interrupt Line Select (ILS) */
222 #define ILS_ALL_INT0	0x0
223 #define ILS_ALL_INT1	0xFFFFFFFF
224 
225 /* Interrupt Line Enable (ILE) */
226 #define ILE_EINT1	BIT(1)
227 #define ILE_EINT0	BIT(0)
228 
229 /* Rx FIFO 0/1 Configuration (RXF0C/RXF1C) */
230 #define RXFC_FWM_SHIFT	24
231 #define RXFC_FWM_MASK	(0x7f << RXFC_FWM_SHIFT)
232 #define RXFC_FS_SHIFT	16
233 #define RXFC_FS_MASK	(0x7f << RXFC_FS_SHIFT)
234 
235 /* Rx FIFO 0/1 Status (RXF0S/RXF1S) */
236 #define RXFS_RFL	BIT(25)
237 #define RXFS_FF		BIT(24)
238 #define RXFS_FPI_SHIFT	16
239 #define RXFS_FPI_MASK	0x3f0000
240 #define RXFS_FGI_SHIFT	8
241 #define RXFS_FGI_MASK	0x3f00
242 #define RXFS_FFL_MASK	0x7f
243 
244 /* Rx Buffer / FIFO Element Size Configuration (RXESC) */
245 #define M_CAN_RXESC_8BYTES	0x0
246 #define M_CAN_RXESC_64BYTES	0x777
247 
248 /* Tx Buffer Configuration(TXBC) */
249 #define TXBC_NDTB_SHIFT		16
250 #define TXBC_NDTB_MASK		(0x3f << TXBC_NDTB_SHIFT)
251 #define TXBC_TFQS_SHIFT		24
252 #define TXBC_TFQS_MASK		(0x3f << TXBC_TFQS_SHIFT)
253 
254 /* Tx FIFO/Queue Status (TXFQS) */
255 #define TXFQS_TFQF		BIT(21)
256 #define TXFQS_TFQPI_SHIFT	16
257 #define TXFQS_TFQPI_MASK	(0x1f << TXFQS_TFQPI_SHIFT)
258 #define TXFQS_TFGI_SHIFT	8
259 #define TXFQS_TFGI_MASK		(0x1f << TXFQS_TFGI_SHIFT)
260 #define TXFQS_TFFL_SHIFT	0
261 #define TXFQS_TFFL_MASK		(0x3f << TXFQS_TFFL_SHIFT)
262 
263 /* Tx Buffer Element Size Configuration(TXESC) */
264 #define TXESC_TBDS_8BYTES	0x0
265 #define TXESC_TBDS_64BYTES	0x7
266 
267 /* Tx Event FIFO Configuration (TXEFC) */
268 #define TXEFC_EFS_SHIFT		16
269 #define TXEFC_EFS_MASK		(0x3f << TXEFC_EFS_SHIFT)
270 
271 /* Tx Event FIFO Status (TXEFS) */
272 #define TXEFS_TEFL		BIT(25)
273 #define TXEFS_EFF		BIT(24)
274 #define TXEFS_EFGI_SHIFT	8
275 #define	TXEFS_EFGI_MASK		(0x1f << TXEFS_EFGI_SHIFT)
276 #define TXEFS_EFFL_SHIFT	0
277 #define TXEFS_EFFL_MASK		(0x3f << TXEFS_EFFL_SHIFT)
278 
279 /* Tx Event FIFO Acknowledge (TXEFA) */
280 #define TXEFA_EFAI_SHIFT	0
281 #define TXEFA_EFAI_MASK		(0x1f << TXEFA_EFAI_SHIFT)
282 
283 /* Message RAM Configuration (in bytes) */
284 #define SIDF_ELEMENT_SIZE	4
285 #define XIDF_ELEMENT_SIZE	8
286 #define RXF0_ELEMENT_SIZE	72
287 #define RXF1_ELEMENT_SIZE	72
288 #define RXB_ELEMENT_SIZE	72
289 #define TXE_ELEMENT_SIZE	8
290 #define TXB_ELEMENT_SIZE	72
291 
292 /* Message RAM Elements */
293 #define M_CAN_FIFO_ID		0x0
294 #define M_CAN_FIFO_DLC		0x4
295 #define M_CAN_FIFO_DATA(n)	(0x8 + ((n) << 2))
296 
297 /* Rx Buffer Element */
298 /* R0 */
299 #define RX_BUF_ESI		BIT(31)
300 #define RX_BUF_XTD		BIT(30)
301 #define RX_BUF_RTR		BIT(29)
302 /* R1 */
303 #define RX_BUF_ANMF		BIT(31)
304 #define RX_BUF_FDF		BIT(21)
305 #define RX_BUF_BRS		BIT(20)
306 
307 /* Tx Buffer Element */
308 /* T0 */
309 #define TX_BUF_ESI		BIT(31)
310 #define TX_BUF_XTD		BIT(30)
311 #define TX_BUF_RTR		BIT(29)
312 /* T1 */
313 #define TX_BUF_EFC		BIT(23)
314 #define TX_BUF_FDF		BIT(21)
315 #define TX_BUF_BRS		BIT(20)
316 #define TX_BUF_MM_SHIFT		24
317 #define TX_BUF_MM_MASK		(0xff << TX_BUF_MM_SHIFT)
318 
319 /* Tx event FIFO Element */
320 /* E1 */
321 #define TX_EVENT_MM_SHIFT	TX_BUF_MM_SHIFT
322 #define TX_EVENT_MM_MASK	(0xff << TX_EVENT_MM_SHIFT)
323 
324 static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)
325 {
326 	return cdev->ops->read_reg(cdev, reg);
327 }
328 
329 static inline void m_can_write(struct m_can_classdev *cdev, enum m_can_reg reg,
330 			       u32 val)
331 {
332 	cdev->ops->write_reg(cdev, reg, val);
333 }
334 
335 static u32 m_can_fifo_read(struct m_can_classdev *cdev,
336 			   u32 fgi, unsigned int offset)
337 {
338 	u32 addr_offset = cdev->mcfg[MRAM_RXF0].off + fgi * RXF0_ELEMENT_SIZE +
339 			  offset;
340 
341 	return cdev->ops->read_fifo(cdev, addr_offset);
342 }
343 
344 static void m_can_fifo_write(struct m_can_classdev *cdev,
345 			     u32 fpi, unsigned int offset, u32 val)
346 {
347 	u32 addr_offset = cdev->mcfg[MRAM_TXB].off + fpi * TXB_ELEMENT_SIZE +
348 			  offset;
349 
350 	cdev->ops->write_fifo(cdev, addr_offset, val);
351 }
352 
353 static inline void m_can_fifo_write_no_off(struct m_can_classdev *cdev,
354 					   u32 fpi, u32 val)
355 {
356 	cdev->ops->write_fifo(cdev, fpi, val);
357 }
358 
359 static u32 m_can_txe_fifo_read(struct m_can_classdev *cdev, u32 fgi, u32 offset)
360 {
361 	u32 addr_offset = cdev->mcfg[MRAM_TXE].off + fgi * TXE_ELEMENT_SIZE +
362 			  offset;
363 
364 	return cdev->ops->read_fifo(cdev, addr_offset);
365 }
366 
367 static inline bool m_can_tx_fifo_full(struct m_can_classdev *cdev)
368 {
369 		return !!(m_can_read(cdev, M_CAN_TXFQS) & TXFQS_TFQF);
370 }
371 
372 void m_can_config_endisable(struct m_can_classdev *cdev, bool enable)
373 {
374 	u32 cccr = m_can_read(cdev, M_CAN_CCCR);
375 	u32 timeout = 10;
376 	u32 val = 0;
377 
378 	/* Clear the Clock stop request if it was set */
379 	if (cccr & CCCR_CSR)
380 		cccr &= ~CCCR_CSR;
381 
382 	if (enable) {
383 		/* Clear the Clock stop request if it was set */
384 		if (cccr & CCCR_CSR)
385 			cccr &= ~CCCR_CSR;
386 
387 		/* enable m_can configuration */
388 		m_can_write(cdev, M_CAN_CCCR, cccr | CCCR_INIT);
389 		udelay(5);
390 		/* CCCR.CCE can only be set/reset while CCCR.INIT = '1' */
391 		m_can_write(cdev, M_CAN_CCCR, cccr | CCCR_INIT | CCCR_CCE);
392 	} else {
393 		m_can_write(cdev, M_CAN_CCCR, cccr & ~(CCCR_INIT | CCCR_CCE));
394 	}
395 
396 	/* there's a delay for module initialization */
397 	if (enable)
398 		val = CCCR_INIT | CCCR_CCE;
399 
400 	while ((m_can_read(cdev, M_CAN_CCCR) & (CCCR_INIT | CCCR_CCE)) != val) {
401 		if (timeout == 0) {
402 			netdev_warn(cdev->net, "Failed to init module\n");
403 			return;
404 		}
405 		timeout--;
406 		udelay(1);
407 	}
408 }
409 
410 static inline void m_can_enable_all_interrupts(struct m_can_classdev *cdev)
411 {
412 	/* Only interrupt line 0 is used in this driver */
413 	m_can_write(cdev, M_CAN_ILE, ILE_EINT0);
414 }
415 
416 static inline void m_can_disable_all_interrupts(struct m_can_classdev *cdev)
417 {
418 	m_can_write(cdev, M_CAN_ILE, 0x0);
419 }
420 
421 static void m_can_clean(struct net_device *net)
422 {
423 	struct m_can_classdev *cdev = netdev_priv(net);
424 
425 	if (cdev->tx_skb) {
426 		int putidx = 0;
427 
428 		net->stats.tx_errors++;
429 		if (cdev->version > 30)
430 			putidx = ((m_can_read(cdev, M_CAN_TXFQS) &
431 				   TXFQS_TFQPI_MASK) >> TXFQS_TFQPI_SHIFT);
432 
433 		can_free_echo_skb(cdev->net, putidx);
434 		cdev->tx_skb = NULL;
435 	}
436 }
437 
438 static void m_can_read_fifo(struct net_device *dev, u32 rxfs)
439 {
440 	struct net_device_stats *stats = &dev->stats;
441 	struct m_can_classdev *cdev = netdev_priv(dev);
442 	struct canfd_frame *cf;
443 	struct sk_buff *skb;
444 	u32 id, fgi, dlc;
445 	int i;
446 
447 	/* calculate the fifo get index for where to read data */
448 	fgi = (rxfs & RXFS_FGI_MASK) >> RXFS_FGI_SHIFT;
449 	dlc = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DLC);
450 	if (dlc & RX_BUF_FDF)
451 		skb = alloc_canfd_skb(dev, &cf);
452 	else
453 		skb = alloc_can_skb(dev, (struct can_frame **)&cf);
454 	if (!skb) {
455 		stats->rx_dropped++;
456 		return;
457 	}
458 
459 	if (dlc & RX_BUF_FDF)
460 		cf->len = can_dlc2len((dlc >> 16) & 0x0F);
461 	else
462 		cf->len = get_can_dlc((dlc >> 16) & 0x0F);
463 
464 	id = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_ID);
465 	if (id & RX_BUF_XTD)
466 		cf->can_id = (id & CAN_EFF_MASK) | CAN_EFF_FLAG;
467 	else
468 		cf->can_id = (id >> 18) & CAN_SFF_MASK;
469 
470 	if (id & RX_BUF_ESI) {
471 		cf->flags |= CANFD_ESI;
472 		netdev_dbg(dev, "ESI Error\n");
473 	}
474 
475 	if (!(dlc & RX_BUF_FDF) && (id & RX_BUF_RTR)) {
476 		cf->can_id |= CAN_RTR_FLAG;
477 	} else {
478 		if (dlc & RX_BUF_BRS)
479 			cf->flags |= CANFD_BRS;
480 
481 		for (i = 0; i < cf->len; i += 4)
482 			*(u32 *)(cf->data + i) =
483 				m_can_fifo_read(cdev, fgi,
484 						M_CAN_FIFO_DATA(i / 4));
485 	}
486 
487 	/* acknowledge rx fifo 0 */
488 	m_can_write(cdev, M_CAN_RXF0A, fgi);
489 
490 	stats->rx_packets++;
491 	stats->rx_bytes += cf->len;
492 
493 	netif_receive_skb(skb);
494 }
495 
496 static int m_can_do_rx_poll(struct net_device *dev, int quota)
497 {
498 	struct m_can_classdev *cdev = netdev_priv(dev);
499 	u32 pkts = 0;
500 	u32 rxfs;
501 
502 	rxfs = m_can_read(cdev, M_CAN_RXF0S);
503 	if (!(rxfs & RXFS_FFL_MASK)) {
504 		netdev_dbg(dev, "no messages in fifo0\n");
505 		return 0;
506 	}
507 
508 	while ((rxfs & RXFS_FFL_MASK) && (quota > 0)) {
509 		if (rxfs & RXFS_RFL)
510 			netdev_warn(dev, "Rx FIFO 0 Message Lost\n");
511 
512 		m_can_read_fifo(dev, rxfs);
513 
514 		quota--;
515 		pkts++;
516 		rxfs = m_can_read(cdev, M_CAN_RXF0S);
517 	}
518 
519 	if (pkts)
520 		can_led_event(dev, CAN_LED_EVENT_RX);
521 
522 	return pkts;
523 }
524 
525 static int m_can_handle_lost_msg(struct net_device *dev)
526 {
527 	struct net_device_stats *stats = &dev->stats;
528 	struct sk_buff *skb;
529 	struct can_frame *frame;
530 
531 	netdev_err(dev, "msg lost in rxf0\n");
532 
533 	stats->rx_errors++;
534 	stats->rx_over_errors++;
535 
536 	skb = alloc_can_err_skb(dev, &frame);
537 	if (unlikely(!skb))
538 		return 0;
539 
540 	frame->can_id |= CAN_ERR_CRTL;
541 	frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
542 
543 	netif_receive_skb(skb);
544 
545 	return 1;
546 }
547 
548 static int m_can_handle_lec_err(struct net_device *dev,
549 				enum m_can_lec_type lec_type)
550 {
551 	struct m_can_classdev *cdev = netdev_priv(dev);
552 	struct net_device_stats *stats = &dev->stats;
553 	struct can_frame *cf;
554 	struct sk_buff *skb;
555 
556 	cdev->can.can_stats.bus_error++;
557 	stats->rx_errors++;
558 
559 	/* propagate the error condition to the CAN stack */
560 	skb = alloc_can_err_skb(dev, &cf);
561 	if (unlikely(!skb))
562 		return 0;
563 
564 	/* check for 'last error code' which tells us the
565 	 * type of the last error to occur on the CAN bus
566 	 */
567 	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
568 
569 	switch (lec_type) {
570 	case LEC_STUFF_ERROR:
571 		netdev_dbg(dev, "stuff error\n");
572 		cf->data[2] |= CAN_ERR_PROT_STUFF;
573 		break;
574 	case LEC_FORM_ERROR:
575 		netdev_dbg(dev, "form error\n");
576 		cf->data[2] |= CAN_ERR_PROT_FORM;
577 		break;
578 	case LEC_ACK_ERROR:
579 		netdev_dbg(dev, "ack error\n");
580 		cf->data[3] = CAN_ERR_PROT_LOC_ACK;
581 		break;
582 	case LEC_BIT1_ERROR:
583 		netdev_dbg(dev, "bit1 error\n");
584 		cf->data[2] |= CAN_ERR_PROT_BIT1;
585 		break;
586 	case LEC_BIT0_ERROR:
587 		netdev_dbg(dev, "bit0 error\n");
588 		cf->data[2] |= CAN_ERR_PROT_BIT0;
589 		break;
590 	case LEC_CRC_ERROR:
591 		netdev_dbg(dev, "CRC error\n");
592 		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
593 		break;
594 	default:
595 		break;
596 	}
597 
598 	stats->rx_packets++;
599 	stats->rx_bytes += cf->can_dlc;
600 	netif_receive_skb(skb);
601 
602 	return 1;
603 }
604 
605 static int __m_can_get_berr_counter(const struct net_device *dev,
606 				    struct can_berr_counter *bec)
607 {
608 	struct m_can_classdev *cdev = netdev_priv(dev);
609 	unsigned int ecr;
610 
611 	ecr = m_can_read(cdev, M_CAN_ECR);
612 	bec->rxerr = (ecr & ECR_REC_MASK) >> ECR_REC_SHIFT;
613 	bec->txerr = (ecr & ECR_TEC_MASK) >> ECR_TEC_SHIFT;
614 
615 	return 0;
616 }
617 
618 static int m_can_clk_start(struct m_can_classdev *cdev)
619 {
620 	int err;
621 
622 	if (cdev->pm_clock_support == 0)
623 		return 0;
624 
625 	err = pm_runtime_get_sync(cdev->dev);
626 	if (err < 0) {
627 		pm_runtime_put_noidle(cdev->dev);
628 		return err;
629 	}
630 
631 	return 0;
632 }
633 
634 static void m_can_clk_stop(struct m_can_classdev *cdev)
635 {
636 	if (cdev->pm_clock_support)
637 		pm_runtime_put_sync(cdev->dev);
638 }
639 
640 static int m_can_get_berr_counter(const struct net_device *dev,
641 				  struct can_berr_counter *bec)
642 {
643 	struct m_can_classdev *cdev = netdev_priv(dev);
644 	int err;
645 
646 	err = m_can_clk_start(cdev);
647 	if (err)
648 		return err;
649 
650 	__m_can_get_berr_counter(dev, bec);
651 
652 	m_can_clk_stop(cdev);
653 
654 	return 0;
655 }
656 
657 static int m_can_handle_state_change(struct net_device *dev,
658 				     enum can_state new_state)
659 {
660 	struct m_can_classdev *cdev = netdev_priv(dev);
661 	struct net_device_stats *stats = &dev->stats;
662 	struct can_frame *cf;
663 	struct sk_buff *skb;
664 	struct can_berr_counter bec;
665 	unsigned int ecr;
666 
667 	switch (new_state) {
668 	case CAN_STATE_ERROR_ACTIVE:
669 		/* error warning state */
670 		cdev->can.can_stats.error_warning++;
671 		cdev->can.state = CAN_STATE_ERROR_WARNING;
672 		break;
673 	case CAN_STATE_ERROR_PASSIVE:
674 		/* error passive state */
675 		cdev->can.can_stats.error_passive++;
676 		cdev->can.state = CAN_STATE_ERROR_PASSIVE;
677 		break;
678 	case CAN_STATE_BUS_OFF:
679 		/* bus-off state */
680 		cdev->can.state = CAN_STATE_BUS_OFF;
681 		m_can_disable_all_interrupts(cdev);
682 		cdev->can.can_stats.bus_off++;
683 		can_bus_off(dev);
684 		break;
685 	default:
686 		break;
687 	}
688 
689 	/* propagate the error condition to the CAN stack */
690 	skb = alloc_can_err_skb(dev, &cf);
691 	if (unlikely(!skb))
692 		return 0;
693 
694 	__m_can_get_berr_counter(dev, &bec);
695 
696 	switch (new_state) {
697 	case CAN_STATE_ERROR_ACTIVE:
698 		/* error warning state */
699 		cf->can_id |= CAN_ERR_CRTL;
700 		cf->data[1] = (bec.txerr > bec.rxerr) ?
701 			CAN_ERR_CRTL_TX_WARNING :
702 			CAN_ERR_CRTL_RX_WARNING;
703 		cf->data[6] = bec.txerr;
704 		cf->data[7] = bec.rxerr;
705 		break;
706 	case CAN_STATE_ERROR_PASSIVE:
707 		/* error passive state */
708 		cf->can_id |= CAN_ERR_CRTL;
709 		ecr = m_can_read(cdev, M_CAN_ECR);
710 		if (ecr & ECR_RP)
711 			cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
712 		if (bec.txerr > 127)
713 			cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
714 		cf->data[6] = bec.txerr;
715 		cf->data[7] = bec.rxerr;
716 		break;
717 	case CAN_STATE_BUS_OFF:
718 		/* bus-off state */
719 		cf->can_id |= CAN_ERR_BUSOFF;
720 		break;
721 	default:
722 		break;
723 	}
724 
725 	stats->rx_packets++;
726 	stats->rx_bytes += cf->can_dlc;
727 	netif_receive_skb(skb);
728 
729 	return 1;
730 }
731 
732 static int m_can_handle_state_errors(struct net_device *dev, u32 psr)
733 {
734 	struct m_can_classdev *cdev = netdev_priv(dev);
735 	int work_done = 0;
736 
737 	if (psr & PSR_EW && cdev->can.state != CAN_STATE_ERROR_WARNING) {
738 		netdev_dbg(dev, "entered error warning state\n");
739 		work_done += m_can_handle_state_change(dev,
740 						       CAN_STATE_ERROR_WARNING);
741 	}
742 
743 	if (psr & PSR_EP && cdev->can.state != CAN_STATE_ERROR_PASSIVE) {
744 		netdev_dbg(dev, "entered error passive state\n");
745 		work_done += m_can_handle_state_change(dev,
746 						       CAN_STATE_ERROR_PASSIVE);
747 	}
748 
749 	if (psr & PSR_BO && cdev->can.state != CAN_STATE_BUS_OFF) {
750 		netdev_dbg(dev, "entered error bus off state\n");
751 		work_done += m_can_handle_state_change(dev,
752 						       CAN_STATE_BUS_OFF);
753 	}
754 
755 	return work_done;
756 }
757 
758 static void m_can_handle_other_err(struct net_device *dev, u32 irqstatus)
759 {
760 	if (irqstatus & IR_WDI)
761 		netdev_err(dev, "Message RAM Watchdog event due to missing READY\n");
762 	if (irqstatus & IR_ELO)
763 		netdev_err(dev, "Error Logging Overflow\n");
764 	if (irqstatus & IR_BEU)
765 		netdev_err(dev, "Bit Error Uncorrected\n");
766 	if (irqstatus & IR_BEC)
767 		netdev_err(dev, "Bit Error Corrected\n");
768 	if (irqstatus & IR_TOO)
769 		netdev_err(dev, "Timeout reached\n");
770 	if (irqstatus & IR_MRAF)
771 		netdev_err(dev, "Message RAM access failure occurred\n");
772 }
773 
774 static inline bool is_lec_err(u32 psr)
775 {
776 	psr &= LEC_UNUSED;
777 
778 	return psr && (psr != LEC_UNUSED);
779 }
780 
781 static inline bool m_can_is_protocol_err(u32 irqstatus)
782 {
783 	return irqstatus & IR_ERR_LEC_31X;
784 }
785 
786 static int m_can_handle_protocol_error(struct net_device *dev, u32 irqstatus)
787 {
788 	struct net_device_stats *stats = &dev->stats;
789 	struct m_can_classdev *cdev = netdev_priv(dev);
790 	struct can_frame *cf;
791 	struct sk_buff *skb;
792 
793 	/* propagate the error condition to the CAN stack */
794 	skb = alloc_can_err_skb(dev, &cf);
795 
796 	/* update tx error stats since there is protocol error */
797 	stats->tx_errors++;
798 
799 	/* update arbitration lost status */
800 	if (cdev->version >= 31 && (irqstatus & IR_PEA)) {
801 		netdev_dbg(dev, "Protocol error in Arbitration fail\n");
802 		cdev->can.can_stats.arbitration_lost++;
803 		if (skb) {
804 			cf->can_id |= CAN_ERR_LOSTARB;
805 			cf->data[0] |= CAN_ERR_LOSTARB_UNSPEC;
806 		}
807 	}
808 
809 	if (unlikely(!skb)) {
810 		netdev_dbg(dev, "allocation of skb failed\n");
811 		return 0;
812 	}
813 	netif_receive_skb(skb);
814 
815 	return 1;
816 }
817 
818 static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus,
819 				   u32 psr)
820 {
821 	struct m_can_classdev *cdev = netdev_priv(dev);
822 	int work_done = 0;
823 
824 	if (irqstatus & IR_RF0L)
825 		work_done += m_can_handle_lost_msg(dev);
826 
827 	/* handle lec errors on the bus */
828 	if ((cdev->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
829 	    is_lec_err(psr))
830 		work_done += m_can_handle_lec_err(dev, psr & LEC_UNUSED);
831 
832 	/* handle protocol errors in arbitration phase */
833 	if ((cdev->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
834 	    m_can_is_protocol_err(irqstatus))
835 		work_done += m_can_handle_protocol_error(dev, irqstatus);
836 
837 	/* other unproccessed error interrupts */
838 	m_can_handle_other_err(dev, irqstatus);
839 
840 	return work_done;
841 }
842 
843 static int m_can_rx_handler(struct net_device *dev, int quota)
844 {
845 	struct m_can_classdev *cdev = netdev_priv(dev);
846 	int work_done = 0;
847 	u32 irqstatus, psr;
848 
849 	irqstatus = cdev->irqstatus | m_can_read(cdev, M_CAN_IR);
850 	if (!irqstatus)
851 		goto end;
852 
853 	/* Errata workaround for issue "Needless activation of MRAF irq"
854 	 * During frame reception while the MCAN is in Error Passive state
855 	 * and the Receive Error Counter has the value MCAN_ECR.REC = 127,
856 	 * it may happen that MCAN_IR.MRAF is set although there was no
857 	 * Message RAM access failure.
858 	 * If MCAN_IR.MRAF is enabled, an interrupt to the Host CPU is generated
859 	 * The Message RAM Access Failure interrupt routine needs to check
860 	 * whether MCAN_ECR.RP = ’1’ and MCAN_ECR.REC = 127.
861 	 * In this case, reset MCAN_IR.MRAF. No further action is required.
862 	 */
863 	if (cdev->version <= 31 && irqstatus & IR_MRAF &&
864 	    m_can_read(cdev, M_CAN_ECR) & ECR_RP) {
865 		struct can_berr_counter bec;
866 
867 		__m_can_get_berr_counter(dev, &bec);
868 		if (bec.rxerr == 127) {
869 			m_can_write(cdev, M_CAN_IR, IR_MRAF);
870 			irqstatus &= ~IR_MRAF;
871 		}
872 	}
873 
874 	psr = m_can_read(cdev, M_CAN_PSR);
875 
876 	if (irqstatus & IR_ERR_STATE)
877 		work_done += m_can_handle_state_errors(dev, psr);
878 
879 	if (irqstatus & IR_ERR_BUS_30X)
880 		work_done += m_can_handle_bus_errors(dev, irqstatus, psr);
881 
882 	if (irqstatus & IR_RF0N)
883 		work_done += m_can_do_rx_poll(dev, (quota - work_done));
884 end:
885 	return work_done;
886 }
887 
888 static int m_can_rx_peripheral(struct net_device *dev)
889 {
890 	struct m_can_classdev *cdev = netdev_priv(dev);
891 
892 	m_can_rx_handler(dev, 1);
893 
894 	m_can_enable_all_interrupts(cdev);
895 
896 	return 0;
897 }
898 
899 static int m_can_poll(struct napi_struct *napi, int quota)
900 {
901 	struct net_device *dev = napi->dev;
902 	struct m_can_classdev *cdev = netdev_priv(dev);
903 	int work_done;
904 
905 	work_done = m_can_rx_handler(dev, quota);
906 	if (work_done < quota) {
907 		napi_complete_done(napi, work_done);
908 		m_can_enable_all_interrupts(cdev);
909 	}
910 
911 	return work_done;
912 }
913 
914 static void m_can_echo_tx_event(struct net_device *dev)
915 {
916 	u32 txe_count = 0;
917 	u32 m_can_txefs;
918 	u32 fgi = 0;
919 	int i = 0;
920 	unsigned int msg_mark;
921 
922 	struct m_can_classdev *cdev = netdev_priv(dev);
923 	struct net_device_stats *stats = &dev->stats;
924 
925 	/* read tx event fifo status */
926 	m_can_txefs = m_can_read(cdev, M_CAN_TXEFS);
927 
928 	/* Get Tx Event fifo element count */
929 	txe_count = (m_can_txefs & TXEFS_EFFL_MASK)
930 			>> TXEFS_EFFL_SHIFT;
931 
932 	/* Get and process all sent elements */
933 	for (i = 0; i < txe_count; i++) {
934 		/* retrieve get index */
935 		fgi = (m_can_read(cdev, M_CAN_TXEFS) & TXEFS_EFGI_MASK)
936 			>> TXEFS_EFGI_SHIFT;
937 
938 		/* get message marker */
939 		msg_mark = (m_can_txe_fifo_read(cdev, fgi, 4) &
940 			    TX_EVENT_MM_MASK) >> TX_EVENT_MM_SHIFT;
941 
942 		/* ack txe element */
943 		m_can_write(cdev, M_CAN_TXEFA, (TXEFA_EFAI_MASK &
944 						(fgi << TXEFA_EFAI_SHIFT)));
945 
946 		/* update stats */
947 		stats->tx_bytes += can_get_echo_skb(dev, msg_mark);
948 		stats->tx_packets++;
949 	}
950 }
951 
952 static irqreturn_t m_can_isr(int irq, void *dev_id)
953 {
954 	struct net_device *dev = (struct net_device *)dev_id;
955 	struct m_can_classdev *cdev = netdev_priv(dev);
956 	struct net_device_stats *stats = &dev->stats;
957 	u32 ir;
958 
959 	ir = m_can_read(cdev, M_CAN_IR);
960 	if (!ir)
961 		return IRQ_NONE;
962 
963 	/* ACK all irqs */
964 	if (ir & IR_ALL_INT)
965 		m_can_write(cdev, M_CAN_IR, ir);
966 
967 	if (cdev->ops->clear_interrupts)
968 		cdev->ops->clear_interrupts(cdev);
969 
970 	/* schedule NAPI in case of
971 	 * - rx IRQ
972 	 * - state change IRQ
973 	 * - bus error IRQ and bus error reporting
974 	 */
975 	if ((ir & IR_RF0N) || (ir & IR_ERR_ALL_30X)) {
976 		cdev->irqstatus = ir;
977 		m_can_disable_all_interrupts(cdev);
978 		if (!cdev->is_peripheral)
979 			napi_schedule(&cdev->napi);
980 		else
981 			m_can_rx_peripheral(dev);
982 	}
983 
984 	if (cdev->version == 30) {
985 		if (ir & IR_TC) {
986 			/* Transmission Complete Interrupt*/
987 			stats->tx_bytes += can_get_echo_skb(dev, 0);
988 			stats->tx_packets++;
989 			can_led_event(dev, CAN_LED_EVENT_TX);
990 			netif_wake_queue(dev);
991 		}
992 	} else  {
993 		if (ir & IR_TEFN) {
994 			/* New TX FIFO Element arrived */
995 			m_can_echo_tx_event(dev);
996 			can_led_event(dev, CAN_LED_EVENT_TX);
997 			if (netif_queue_stopped(dev) &&
998 			    !m_can_tx_fifo_full(cdev))
999 				netif_wake_queue(dev);
1000 		}
1001 	}
1002 
1003 	return IRQ_HANDLED;
1004 }
1005 
1006 static const struct can_bittiming_const m_can_bittiming_const_30X = {
1007 	.name = KBUILD_MODNAME,
1008 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
1009 	.tseg1_max = 64,
1010 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1011 	.tseg2_max = 16,
1012 	.sjw_max = 16,
1013 	.brp_min = 1,
1014 	.brp_max = 1024,
1015 	.brp_inc = 1,
1016 };
1017 
1018 static const struct can_bittiming_const m_can_data_bittiming_const_30X = {
1019 	.name = KBUILD_MODNAME,
1020 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
1021 	.tseg1_max = 16,
1022 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1023 	.tseg2_max = 8,
1024 	.sjw_max = 4,
1025 	.brp_min = 1,
1026 	.brp_max = 32,
1027 	.brp_inc = 1,
1028 };
1029 
1030 static const struct can_bittiming_const m_can_bittiming_const_31X = {
1031 	.name = KBUILD_MODNAME,
1032 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
1033 	.tseg1_max = 256,
1034 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1035 	.tseg2_max = 128,
1036 	.sjw_max = 128,
1037 	.brp_min = 1,
1038 	.brp_max = 512,
1039 	.brp_inc = 1,
1040 };
1041 
1042 static const struct can_bittiming_const m_can_data_bittiming_const_31X = {
1043 	.name = KBUILD_MODNAME,
1044 	.tseg1_min = 1,		/* Time segment 1 = prop_seg + phase_seg1 */
1045 	.tseg1_max = 32,
1046 	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
1047 	.tseg2_max = 16,
1048 	.sjw_max = 16,
1049 	.brp_min = 1,
1050 	.brp_max = 32,
1051 	.brp_inc = 1,
1052 };
1053 
1054 static int m_can_set_bittiming(struct net_device *dev)
1055 {
1056 	struct m_can_classdev *cdev = netdev_priv(dev);
1057 	const struct can_bittiming *bt = &cdev->can.bittiming;
1058 	const struct can_bittiming *dbt = &cdev->can.data_bittiming;
1059 	u16 brp, sjw, tseg1, tseg2;
1060 	u32 reg_btp;
1061 
1062 	brp = bt->brp - 1;
1063 	sjw = bt->sjw - 1;
1064 	tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
1065 	tseg2 = bt->phase_seg2 - 1;
1066 	reg_btp = (brp << NBTP_NBRP_SHIFT) | (sjw << NBTP_NSJW_SHIFT) |
1067 		(tseg1 << NBTP_NTSEG1_SHIFT) | (tseg2 << NBTP_NTSEG2_SHIFT);
1068 	m_can_write(cdev, M_CAN_NBTP, reg_btp);
1069 
1070 	if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
1071 		reg_btp = 0;
1072 		brp = dbt->brp - 1;
1073 		sjw = dbt->sjw - 1;
1074 		tseg1 = dbt->prop_seg + dbt->phase_seg1 - 1;
1075 		tseg2 = dbt->phase_seg2 - 1;
1076 
1077 		/* TDC is only needed for bitrates beyond 2.5 MBit/s.
1078 		 * This is mentioned in the "Bit Time Requirements for CAN FD"
1079 		 * paper presented at the International CAN Conference 2013
1080 		 */
1081 		if (dbt->bitrate > 2500000) {
1082 			u32 tdco, ssp;
1083 
1084 			/* Use the same value of secondary sampling point
1085 			 * as the data sampling point
1086 			 */
1087 			ssp = dbt->sample_point;
1088 
1089 			/* Equation based on Bosch's M_CAN User Manual's
1090 			 * Transmitter Delay Compensation Section
1091 			 */
1092 			tdco = (cdev->can.clock.freq / 1000) *
1093 			       ssp / dbt->bitrate;
1094 
1095 			/* Max valid TDCO value is 127 */
1096 			if (tdco > 127) {
1097 				netdev_warn(dev, "TDCO value of %u is beyond maximum. Using maximum possible value\n",
1098 					    tdco);
1099 				tdco = 127;
1100 			}
1101 
1102 			reg_btp |= DBTP_TDC;
1103 			m_can_write(cdev, M_CAN_TDCR,
1104 				    tdco << TDCR_TDCO_SHIFT);
1105 		}
1106 
1107 		reg_btp |= (brp << DBTP_DBRP_SHIFT) |
1108 			   (sjw << DBTP_DSJW_SHIFT) |
1109 			   (tseg1 << DBTP_DTSEG1_SHIFT) |
1110 			   (tseg2 << DBTP_DTSEG2_SHIFT);
1111 
1112 		m_can_write(cdev, M_CAN_DBTP, reg_btp);
1113 	}
1114 
1115 	return 0;
1116 }
1117 
1118 /* Configure M_CAN chip:
1119  * - set rx buffer/fifo element size
1120  * - configure rx fifo
1121  * - accept non-matching frame into fifo 0
1122  * - configure tx buffer
1123  *		- >= v3.1.x: TX FIFO is used
1124  * - configure mode
1125  * - setup bittiming
1126  */
1127 static void m_can_chip_config(struct net_device *dev)
1128 {
1129 	struct m_can_classdev *cdev = netdev_priv(dev);
1130 	u32 cccr, test;
1131 
1132 	m_can_config_endisable(cdev, true);
1133 
1134 	/* RX Buffer/FIFO Element Size 64 bytes data field */
1135 	m_can_write(cdev, M_CAN_RXESC, M_CAN_RXESC_64BYTES);
1136 
1137 	/* Accept Non-matching Frames Into FIFO 0 */
1138 	m_can_write(cdev, M_CAN_GFC, 0x0);
1139 
1140 	if (cdev->version == 30) {
1141 		/* only support one Tx Buffer currently */
1142 		m_can_write(cdev, M_CAN_TXBC, (1 << TXBC_NDTB_SHIFT) |
1143 				cdev->mcfg[MRAM_TXB].off);
1144 	} else {
1145 		/* TX FIFO is used for newer IP Core versions */
1146 		m_can_write(cdev, M_CAN_TXBC,
1147 			    (cdev->mcfg[MRAM_TXB].num << TXBC_TFQS_SHIFT) |
1148 			    (cdev->mcfg[MRAM_TXB].off));
1149 	}
1150 
1151 	/* support 64 bytes payload */
1152 	m_can_write(cdev, M_CAN_TXESC, TXESC_TBDS_64BYTES);
1153 
1154 	/* TX Event FIFO */
1155 	if (cdev->version == 30) {
1156 		m_can_write(cdev, M_CAN_TXEFC, (1 << TXEFC_EFS_SHIFT) |
1157 				cdev->mcfg[MRAM_TXE].off);
1158 	} else {
1159 		/* Full TX Event FIFO is used */
1160 		m_can_write(cdev, M_CAN_TXEFC,
1161 			    ((cdev->mcfg[MRAM_TXE].num << TXEFC_EFS_SHIFT)
1162 			     & TXEFC_EFS_MASK) |
1163 			    cdev->mcfg[MRAM_TXE].off);
1164 	}
1165 
1166 	/* rx fifo configuration, blocking mode, fifo size 1 */
1167 	m_can_write(cdev, M_CAN_RXF0C,
1168 		    (cdev->mcfg[MRAM_RXF0].num << RXFC_FS_SHIFT) |
1169 		     cdev->mcfg[MRAM_RXF0].off);
1170 
1171 	m_can_write(cdev, M_CAN_RXF1C,
1172 		    (cdev->mcfg[MRAM_RXF1].num << RXFC_FS_SHIFT) |
1173 		     cdev->mcfg[MRAM_RXF1].off);
1174 
1175 	cccr = m_can_read(cdev, M_CAN_CCCR);
1176 	test = m_can_read(cdev, M_CAN_TEST);
1177 	test &= ~TEST_LBCK;
1178 	if (cdev->version == 30) {
1179 	/* Version 3.0.x */
1180 
1181 		cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_DAR |
1182 			(CCCR_CMR_MASK << CCCR_CMR_SHIFT) |
1183 			(CCCR_CME_MASK << CCCR_CME_SHIFT));
1184 
1185 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD)
1186 			cccr |= CCCR_CME_CANFD_BRS << CCCR_CME_SHIFT;
1187 
1188 	} else {
1189 	/* Version 3.1.x or 3.2.x */
1190 		cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE |
1191 			  CCCR_NISO | CCCR_DAR);
1192 
1193 		/* Only 3.2.x has NISO Bit implemented */
1194 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
1195 			cccr |= CCCR_NISO;
1196 
1197 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD)
1198 			cccr |= (CCCR_BRSE | CCCR_FDOE);
1199 	}
1200 
1201 	/* Loopback Mode */
1202 	if (cdev->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
1203 		cccr |= CCCR_TEST | CCCR_MON;
1204 		test |= TEST_LBCK;
1205 	}
1206 
1207 	/* Enable Monitoring (all versions) */
1208 	if (cdev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
1209 		cccr |= CCCR_MON;
1210 
1211 	/* Disable Auto Retransmission (all versions) */
1212 	if (cdev->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
1213 		cccr |= CCCR_DAR;
1214 
1215 	/* Write config */
1216 	m_can_write(cdev, M_CAN_CCCR, cccr);
1217 	m_can_write(cdev, M_CAN_TEST, test);
1218 
1219 	/* Enable interrupts */
1220 	m_can_write(cdev, M_CAN_IR, IR_ALL_INT);
1221 	if (!(cdev->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
1222 		if (cdev->version == 30)
1223 			m_can_write(cdev, M_CAN_IE, IR_ALL_INT &
1224 				    ~(IR_ERR_LEC_30X));
1225 		else
1226 			m_can_write(cdev, M_CAN_IE, IR_ALL_INT &
1227 				    ~(IR_ERR_LEC_31X));
1228 	else
1229 		m_can_write(cdev, M_CAN_IE, IR_ALL_INT);
1230 
1231 	/* route all interrupts to INT0 */
1232 	m_can_write(cdev, M_CAN_ILS, ILS_ALL_INT0);
1233 
1234 	/* set bittiming params */
1235 	m_can_set_bittiming(dev);
1236 
1237 	m_can_config_endisable(cdev, false);
1238 
1239 	if (cdev->ops->init)
1240 		cdev->ops->init(cdev);
1241 }
1242 
1243 static void m_can_start(struct net_device *dev)
1244 {
1245 	struct m_can_classdev *cdev = netdev_priv(dev);
1246 
1247 	/* basic m_can configuration */
1248 	m_can_chip_config(dev);
1249 
1250 	cdev->can.state = CAN_STATE_ERROR_ACTIVE;
1251 
1252 	m_can_enable_all_interrupts(cdev);
1253 }
1254 
1255 static int m_can_set_mode(struct net_device *dev, enum can_mode mode)
1256 {
1257 	switch (mode) {
1258 	case CAN_MODE_START:
1259 		m_can_clean(dev);
1260 		m_can_start(dev);
1261 		netif_wake_queue(dev);
1262 		break;
1263 	default:
1264 		return -EOPNOTSUPP;
1265 	}
1266 
1267 	return 0;
1268 }
1269 
1270 /* Checks core release number of M_CAN
1271  * returns 0 if an unsupported device is detected
1272  * else it returns the release and step coded as:
1273  * return value = 10 * <release> + 1 * <step>
1274  */
1275 static int m_can_check_core_release(struct m_can_classdev *cdev)
1276 {
1277 	u32 crel_reg;
1278 	u8 rel;
1279 	u8 step;
1280 	int res;
1281 
1282 	/* Read Core Release Version and split into version number
1283 	 * Example: Version 3.2.1 => rel = 3; step = 2; substep = 1;
1284 	 */
1285 	crel_reg = m_can_read(cdev, M_CAN_CREL);
1286 	rel = (u8)((crel_reg & CREL_REL_MASK) >> CREL_REL_SHIFT);
1287 	step = (u8)((crel_reg & CREL_STEP_MASK) >> CREL_STEP_SHIFT);
1288 
1289 	if (rel == 3) {
1290 		/* M_CAN v3.x.y: create return value */
1291 		res = 30 + step;
1292 	} else {
1293 		/* Unsupported M_CAN version */
1294 		res = 0;
1295 	}
1296 
1297 	return res;
1298 }
1299 
1300 /* Selectable Non ISO support only in version 3.2.x
1301  * This function checks if the bit is writable.
1302  */
1303 static bool m_can_niso_supported(struct m_can_classdev *cdev)
1304 {
1305 	u32 cccr_reg, cccr_poll = 0;
1306 	int niso_timeout = -ETIMEDOUT;
1307 	int i;
1308 
1309 	m_can_config_endisable(cdev, true);
1310 	cccr_reg = m_can_read(cdev, M_CAN_CCCR);
1311 	cccr_reg |= CCCR_NISO;
1312 	m_can_write(cdev, M_CAN_CCCR, cccr_reg);
1313 
1314 	for (i = 0; i <= 10; i++) {
1315 		cccr_poll = m_can_read(cdev, M_CAN_CCCR);
1316 		if (cccr_poll == cccr_reg) {
1317 			niso_timeout = 0;
1318 			break;
1319 		}
1320 
1321 		usleep_range(1, 5);
1322 	}
1323 
1324 	/* Clear NISO */
1325 	cccr_reg &= ~(CCCR_NISO);
1326 	m_can_write(cdev, M_CAN_CCCR, cccr_reg);
1327 
1328 	m_can_config_endisable(cdev, false);
1329 
1330 	/* return false if time out (-ETIMEDOUT), else return true */
1331 	return !niso_timeout;
1332 }
1333 
1334 static int m_can_dev_setup(struct m_can_classdev *m_can_dev)
1335 {
1336 	struct net_device *dev = m_can_dev->net;
1337 	int m_can_version;
1338 
1339 	m_can_version = m_can_check_core_release(m_can_dev);
1340 	/* return if unsupported version */
1341 	if (!m_can_version) {
1342 		dev_err(m_can_dev->dev, "Unsupported version number: %2d",
1343 			m_can_version);
1344 		return -EINVAL;
1345 	}
1346 
1347 	if (!m_can_dev->is_peripheral)
1348 		netif_napi_add(dev, &m_can_dev->napi,
1349 			       m_can_poll, M_CAN_NAPI_WEIGHT);
1350 
1351 	/* Shared properties of all M_CAN versions */
1352 	m_can_dev->version = m_can_version;
1353 	m_can_dev->can.do_set_mode = m_can_set_mode;
1354 	m_can_dev->can.do_get_berr_counter = m_can_get_berr_counter;
1355 
1356 	/* Set M_CAN supported operations */
1357 	m_can_dev->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
1358 					CAN_CTRLMODE_LISTENONLY |
1359 					CAN_CTRLMODE_BERR_REPORTING |
1360 					CAN_CTRLMODE_FD |
1361 					CAN_CTRLMODE_ONE_SHOT;
1362 
1363 	/* Set properties depending on M_CAN version */
1364 	switch (m_can_dev->version) {
1365 	case 30:
1366 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.0.x */
1367 		can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
1368 		m_can_dev->can.bittiming_const = m_can_dev->bit_timing ?
1369 			m_can_dev->bit_timing : &m_can_bittiming_const_30X;
1370 
1371 		m_can_dev->can.data_bittiming_const = m_can_dev->data_timing ?
1372 						m_can_dev->data_timing :
1373 						&m_can_data_bittiming_const_30X;
1374 		break;
1375 	case 31:
1376 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.1.x */
1377 		can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
1378 		m_can_dev->can.bittiming_const = m_can_dev->bit_timing ?
1379 			m_can_dev->bit_timing : &m_can_bittiming_const_31X;
1380 
1381 		m_can_dev->can.data_bittiming_const = m_can_dev->data_timing ?
1382 						m_can_dev->data_timing :
1383 						&m_can_data_bittiming_const_31X;
1384 		break;
1385 	case 32:
1386 		m_can_dev->can.bittiming_const = m_can_dev->bit_timing ?
1387 			m_can_dev->bit_timing : &m_can_bittiming_const_31X;
1388 
1389 		m_can_dev->can.data_bittiming_const = m_can_dev->data_timing ?
1390 						m_can_dev->data_timing :
1391 						&m_can_data_bittiming_const_31X;
1392 
1393 		m_can_dev->can.ctrlmode_supported |=
1394 						(m_can_niso_supported(m_can_dev)
1395 						? CAN_CTRLMODE_FD_NON_ISO
1396 						: 0);
1397 		break;
1398 	default:
1399 		dev_err(m_can_dev->dev, "Unsupported version number: %2d",
1400 			m_can_dev->version);
1401 		return -EINVAL;
1402 	}
1403 
1404 	if (m_can_dev->ops->init)
1405 		m_can_dev->ops->init(m_can_dev);
1406 
1407 	return 0;
1408 }
1409 
1410 static void m_can_stop(struct net_device *dev)
1411 {
1412 	struct m_can_classdev *cdev = netdev_priv(dev);
1413 
1414 	/* disable all interrupts */
1415 	m_can_disable_all_interrupts(cdev);
1416 
1417 	/* set the state as STOPPED */
1418 	cdev->can.state = CAN_STATE_STOPPED;
1419 }
1420 
1421 static int m_can_close(struct net_device *dev)
1422 {
1423 	struct m_can_classdev *cdev = netdev_priv(dev);
1424 
1425 	netif_stop_queue(dev);
1426 
1427 	if (!cdev->is_peripheral)
1428 		napi_disable(&cdev->napi);
1429 
1430 	m_can_stop(dev);
1431 	m_can_clk_stop(cdev);
1432 	free_irq(dev->irq, dev);
1433 
1434 	if (cdev->is_peripheral) {
1435 		cdev->tx_skb = NULL;
1436 		destroy_workqueue(cdev->tx_wq);
1437 		cdev->tx_wq = NULL;
1438 	}
1439 
1440 	close_candev(dev);
1441 	can_led_event(dev, CAN_LED_EVENT_STOP);
1442 
1443 	return 0;
1444 }
1445 
1446 static int m_can_next_echo_skb_occupied(struct net_device *dev, int putidx)
1447 {
1448 	struct m_can_classdev *cdev = netdev_priv(dev);
1449 	/*get wrap around for loopback skb index */
1450 	unsigned int wrap = cdev->can.echo_skb_max;
1451 	int next_idx;
1452 
1453 	/* calculate next index */
1454 	next_idx = (++putidx >= wrap ? 0 : putidx);
1455 
1456 	/* check if occupied */
1457 	return !!cdev->can.echo_skb[next_idx];
1458 }
1459 
1460 static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
1461 {
1462 	struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
1463 	struct net_device *dev = cdev->net;
1464 	struct sk_buff *skb = cdev->tx_skb;
1465 	u32 id, cccr, fdflags;
1466 	int i;
1467 	int putidx;
1468 
1469 	/* Generate ID field for TX buffer Element */
1470 	/* Common to all supported M_CAN versions */
1471 	if (cf->can_id & CAN_EFF_FLAG) {
1472 		id = cf->can_id & CAN_EFF_MASK;
1473 		id |= TX_BUF_XTD;
1474 	} else {
1475 		id = ((cf->can_id & CAN_SFF_MASK) << 18);
1476 	}
1477 
1478 	if (cf->can_id & CAN_RTR_FLAG)
1479 		id |= TX_BUF_RTR;
1480 
1481 	if (cdev->version == 30) {
1482 		netif_stop_queue(dev);
1483 
1484 		/* message ram configuration */
1485 		m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, id);
1486 		m_can_fifo_write(cdev, 0, M_CAN_FIFO_DLC,
1487 				 can_len2dlc(cf->len) << 16);
1488 
1489 		for (i = 0; i < cf->len; i += 4)
1490 			m_can_fifo_write(cdev, 0,
1491 					 M_CAN_FIFO_DATA(i / 4),
1492 					 *(u32 *)(cf->data + i));
1493 
1494 		can_put_echo_skb(skb, dev, 0);
1495 
1496 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
1497 			cccr = m_can_read(cdev, M_CAN_CCCR);
1498 			cccr &= ~(CCCR_CMR_MASK << CCCR_CMR_SHIFT);
1499 			if (can_is_canfd_skb(skb)) {
1500 				if (cf->flags & CANFD_BRS)
1501 					cccr |= CCCR_CMR_CANFD_BRS <<
1502 						CCCR_CMR_SHIFT;
1503 				else
1504 					cccr |= CCCR_CMR_CANFD <<
1505 						CCCR_CMR_SHIFT;
1506 			} else {
1507 				cccr |= CCCR_CMR_CAN << CCCR_CMR_SHIFT;
1508 			}
1509 			m_can_write(cdev, M_CAN_CCCR, cccr);
1510 		}
1511 		m_can_write(cdev, M_CAN_TXBTIE, 0x1);
1512 		m_can_write(cdev, M_CAN_TXBAR, 0x1);
1513 		/* End of xmit function for version 3.0.x */
1514 	} else {
1515 		/* Transmit routine for version >= v3.1.x */
1516 
1517 		/* Check if FIFO full */
1518 		if (m_can_tx_fifo_full(cdev)) {
1519 			/* This shouldn't happen */
1520 			netif_stop_queue(dev);
1521 			netdev_warn(dev,
1522 				    "TX queue active although FIFO is full.");
1523 
1524 			if (cdev->is_peripheral) {
1525 				kfree_skb(skb);
1526 				dev->stats.tx_dropped++;
1527 				return NETDEV_TX_OK;
1528 			} else {
1529 				return NETDEV_TX_BUSY;
1530 			}
1531 		}
1532 
1533 		/* get put index for frame */
1534 		putidx = ((m_can_read(cdev, M_CAN_TXFQS) & TXFQS_TFQPI_MASK)
1535 				  >> TXFQS_TFQPI_SHIFT);
1536 		/* Write ID Field to FIFO Element */
1537 		m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, id);
1538 
1539 		/* get CAN FD configuration of frame */
1540 		fdflags = 0;
1541 		if (can_is_canfd_skb(skb)) {
1542 			fdflags |= TX_BUF_FDF;
1543 			if (cf->flags & CANFD_BRS)
1544 				fdflags |= TX_BUF_BRS;
1545 		}
1546 
1547 		/* Construct DLC Field. Also contains CAN-FD configuration
1548 		 * use put index of fifo as message marker
1549 		 * it is used in TX interrupt for
1550 		 * sending the correct echo frame
1551 		 */
1552 		m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DLC,
1553 				 ((putidx << TX_BUF_MM_SHIFT) &
1554 				  TX_BUF_MM_MASK) |
1555 				 (can_len2dlc(cf->len) << 16) |
1556 				 fdflags | TX_BUF_EFC);
1557 
1558 		for (i = 0; i < cf->len; i += 4)
1559 			m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA(i / 4),
1560 					 *(u32 *)(cf->data + i));
1561 
1562 		/* Push loopback echo.
1563 		 * Will be looped back on TX interrupt based on message marker
1564 		 */
1565 		can_put_echo_skb(skb, dev, putidx);
1566 
1567 		/* Enable TX FIFO element to start transfer  */
1568 		m_can_write(cdev, M_CAN_TXBAR, (1 << putidx));
1569 
1570 		/* stop network queue if fifo full */
1571 		if (m_can_tx_fifo_full(cdev) ||
1572 		    m_can_next_echo_skb_occupied(dev, putidx))
1573 			netif_stop_queue(dev);
1574 	}
1575 
1576 	return NETDEV_TX_OK;
1577 }
1578 
1579 static void m_can_tx_work_queue(struct work_struct *ws)
1580 {
1581 	struct m_can_classdev *cdev = container_of(ws, struct m_can_classdev,
1582 						tx_work);
1583 
1584 	m_can_tx_handler(cdev);
1585 	cdev->tx_skb = NULL;
1586 }
1587 
1588 static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
1589 				    struct net_device *dev)
1590 {
1591 	struct m_can_classdev *cdev = netdev_priv(dev);
1592 
1593 	if (can_dropped_invalid_skb(dev, skb))
1594 		return NETDEV_TX_OK;
1595 
1596 	if (cdev->is_peripheral) {
1597 		if (cdev->tx_skb) {
1598 			netdev_err(dev, "hard_xmit called while tx busy\n");
1599 			return NETDEV_TX_BUSY;
1600 		}
1601 
1602 		if (cdev->can.state == CAN_STATE_BUS_OFF) {
1603 			m_can_clean(dev);
1604 		} else {
1605 			/* Need to stop the queue to avoid numerous requests
1606 			 * from being sent.  Suggested improvement is to create
1607 			 * a queueing mechanism that will queue the skbs and
1608 			 * process them in order.
1609 			 */
1610 			cdev->tx_skb = skb;
1611 			netif_stop_queue(cdev->net);
1612 			queue_work(cdev->tx_wq, &cdev->tx_work);
1613 		}
1614 	} else {
1615 		cdev->tx_skb = skb;
1616 		return m_can_tx_handler(cdev);
1617 	}
1618 
1619 	return NETDEV_TX_OK;
1620 }
1621 
1622 static int m_can_open(struct net_device *dev)
1623 {
1624 	struct m_can_classdev *cdev = netdev_priv(dev);
1625 	int err;
1626 
1627 	err = m_can_clk_start(cdev);
1628 	if (err)
1629 		return err;
1630 
1631 	/* open the can device */
1632 	err = open_candev(dev);
1633 	if (err) {
1634 		netdev_err(dev, "failed to open can device\n");
1635 		goto exit_disable_clks;
1636 	}
1637 
1638 	/* register interrupt handler */
1639 	if (cdev->is_peripheral) {
1640 		cdev->tx_skb = NULL;
1641 		cdev->tx_wq = alloc_workqueue("mcan_wq",
1642 					      WQ_FREEZABLE | WQ_MEM_RECLAIM, 0);
1643 		if (!cdev->tx_wq) {
1644 			err = -ENOMEM;
1645 			goto out_wq_fail;
1646 		}
1647 
1648 		INIT_WORK(&cdev->tx_work, m_can_tx_work_queue);
1649 
1650 		err = request_threaded_irq(dev->irq, NULL, m_can_isr,
1651 					   IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
1652 					   dev->name, dev);
1653 	} else {
1654 		err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
1655 				  dev);
1656 	}
1657 
1658 	if (err < 0) {
1659 		netdev_err(dev, "failed to request interrupt\n");
1660 		goto exit_irq_fail;
1661 	}
1662 
1663 	/* start the m_can controller */
1664 	m_can_start(dev);
1665 
1666 	can_led_event(dev, CAN_LED_EVENT_OPEN);
1667 
1668 	if (!cdev->is_peripheral)
1669 		napi_enable(&cdev->napi);
1670 
1671 	netif_start_queue(dev);
1672 
1673 	return 0;
1674 
1675 exit_irq_fail:
1676 	if (cdev->is_peripheral)
1677 		destroy_workqueue(cdev->tx_wq);
1678 out_wq_fail:
1679 	close_candev(dev);
1680 exit_disable_clks:
1681 	m_can_clk_stop(cdev);
1682 	return err;
1683 }
1684 
1685 static const struct net_device_ops m_can_netdev_ops = {
1686 	.ndo_open = m_can_open,
1687 	.ndo_stop = m_can_close,
1688 	.ndo_start_xmit = m_can_start_xmit,
1689 	.ndo_change_mtu = can_change_mtu,
1690 };
1691 
1692 static int register_m_can_dev(struct net_device *dev)
1693 {
1694 	dev->flags |= IFF_ECHO;	/* we support local echo */
1695 	dev->netdev_ops = &m_can_netdev_ops;
1696 
1697 	return register_candev(dev);
1698 }
1699 
1700 static void m_can_of_parse_mram(struct m_can_classdev *cdev,
1701 				const u32 *mram_config_vals)
1702 {
1703 	cdev->mcfg[MRAM_SIDF].off = mram_config_vals[0];
1704 	cdev->mcfg[MRAM_SIDF].num = mram_config_vals[1];
1705 	cdev->mcfg[MRAM_XIDF].off = cdev->mcfg[MRAM_SIDF].off +
1706 			cdev->mcfg[MRAM_SIDF].num * SIDF_ELEMENT_SIZE;
1707 	cdev->mcfg[MRAM_XIDF].num = mram_config_vals[2];
1708 	cdev->mcfg[MRAM_RXF0].off = cdev->mcfg[MRAM_XIDF].off +
1709 			cdev->mcfg[MRAM_XIDF].num * XIDF_ELEMENT_SIZE;
1710 	cdev->mcfg[MRAM_RXF0].num = mram_config_vals[3] &
1711 			(RXFC_FS_MASK >> RXFC_FS_SHIFT);
1712 	cdev->mcfg[MRAM_RXF1].off = cdev->mcfg[MRAM_RXF0].off +
1713 			cdev->mcfg[MRAM_RXF0].num * RXF0_ELEMENT_SIZE;
1714 	cdev->mcfg[MRAM_RXF1].num = mram_config_vals[4] &
1715 			(RXFC_FS_MASK >> RXFC_FS_SHIFT);
1716 	cdev->mcfg[MRAM_RXB].off = cdev->mcfg[MRAM_RXF1].off +
1717 			cdev->mcfg[MRAM_RXF1].num * RXF1_ELEMENT_SIZE;
1718 	cdev->mcfg[MRAM_RXB].num = mram_config_vals[5];
1719 	cdev->mcfg[MRAM_TXE].off = cdev->mcfg[MRAM_RXB].off +
1720 			cdev->mcfg[MRAM_RXB].num * RXB_ELEMENT_SIZE;
1721 	cdev->mcfg[MRAM_TXE].num = mram_config_vals[6];
1722 	cdev->mcfg[MRAM_TXB].off = cdev->mcfg[MRAM_TXE].off +
1723 			cdev->mcfg[MRAM_TXE].num * TXE_ELEMENT_SIZE;
1724 	cdev->mcfg[MRAM_TXB].num = mram_config_vals[7] &
1725 			(TXBC_NDTB_MASK >> TXBC_NDTB_SHIFT);
1726 
1727 	dev_dbg(cdev->dev,
1728 		"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",
1729 		cdev->mcfg[MRAM_SIDF].off, cdev->mcfg[MRAM_SIDF].num,
1730 		cdev->mcfg[MRAM_XIDF].off, cdev->mcfg[MRAM_XIDF].num,
1731 		cdev->mcfg[MRAM_RXF0].off, cdev->mcfg[MRAM_RXF0].num,
1732 		cdev->mcfg[MRAM_RXF1].off, cdev->mcfg[MRAM_RXF1].num,
1733 		cdev->mcfg[MRAM_RXB].off, cdev->mcfg[MRAM_RXB].num,
1734 		cdev->mcfg[MRAM_TXE].off, cdev->mcfg[MRAM_TXE].num,
1735 		cdev->mcfg[MRAM_TXB].off, cdev->mcfg[MRAM_TXB].num);
1736 }
1737 
1738 void m_can_init_ram(struct m_can_classdev *cdev)
1739 {
1740 	int end, i, start;
1741 
1742 	/* initialize the entire Message RAM in use to avoid possible
1743 	 * ECC/parity checksum errors when reading an uninitialized buffer
1744 	 */
1745 	start = cdev->mcfg[MRAM_SIDF].off;
1746 	end = cdev->mcfg[MRAM_TXB].off +
1747 		cdev->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE;
1748 
1749 	for (i = start; i < end; i += 4)
1750 		m_can_fifo_write_no_off(cdev, i, 0x0);
1751 }
1752 EXPORT_SYMBOL_GPL(m_can_init_ram);
1753 
1754 int m_can_class_get_clocks(struct m_can_classdev *m_can_dev)
1755 {
1756 	int ret = 0;
1757 
1758 	m_can_dev->hclk = devm_clk_get(m_can_dev->dev, "hclk");
1759 	m_can_dev->cclk = devm_clk_get(m_can_dev->dev, "cclk");
1760 
1761 	if (IS_ERR(m_can_dev->cclk)) {
1762 		dev_err(m_can_dev->dev, "no clock found\n");
1763 		ret = -ENODEV;
1764 	}
1765 
1766 	return ret;
1767 }
1768 EXPORT_SYMBOL_GPL(m_can_class_get_clocks);
1769 
1770 struct m_can_classdev *m_can_class_allocate_dev(struct device *dev)
1771 {
1772 	struct m_can_classdev *class_dev = NULL;
1773 	u32 mram_config_vals[MRAM_CFG_LEN];
1774 	struct net_device *net_dev;
1775 	u32 tx_fifo_size;
1776 	int ret;
1777 
1778 	ret = fwnode_property_read_u32_array(dev_fwnode(dev),
1779 					     "bosch,mram-cfg",
1780 					     mram_config_vals,
1781 					     sizeof(mram_config_vals) / 4);
1782 	if (ret) {
1783 		dev_err(dev, "Could not get Message RAM configuration.");
1784 		goto out;
1785 	}
1786 
1787 	/* Get TX FIFO size
1788 	 * Defines the total amount of echo buffers for loopback
1789 	 */
1790 	tx_fifo_size = mram_config_vals[7];
1791 
1792 	/* allocate the m_can device */
1793 	net_dev = alloc_candev(sizeof(*class_dev), tx_fifo_size);
1794 	if (!net_dev) {
1795 		dev_err(dev, "Failed to allocate CAN device");
1796 		goto out;
1797 	}
1798 
1799 	class_dev = netdev_priv(net_dev);
1800 	if (!class_dev) {
1801 		dev_err(dev, "Failed to init netdev cdevate");
1802 		goto out;
1803 	}
1804 
1805 	class_dev->net = net_dev;
1806 	class_dev->dev = dev;
1807 	SET_NETDEV_DEV(net_dev, dev);
1808 
1809 	m_can_of_parse_mram(class_dev, mram_config_vals);
1810 out:
1811 	return class_dev;
1812 }
1813 EXPORT_SYMBOL_GPL(m_can_class_allocate_dev);
1814 
1815 int m_can_class_register(struct m_can_classdev *m_can_dev)
1816 {
1817 	int ret;
1818 
1819 	if (m_can_dev->pm_clock_support) {
1820 		pm_runtime_enable(m_can_dev->dev);
1821 		ret = m_can_clk_start(m_can_dev);
1822 		if (ret)
1823 			goto pm_runtime_fail;
1824 	}
1825 
1826 	ret = m_can_dev_setup(m_can_dev);
1827 	if (ret)
1828 		goto clk_disable;
1829 
1830 	ret = register_m_can_dev(m_can_dev->net);
1831 	if (ret) {
1832 		dev_err(m_can_dev->dev, "registering %s failed (err=%d)\n",
1833 			m_can_dev->net->name, ret);
1834 		goto clk_disable;
1835 	}
1836 
1837 	devm_can_led_init(m_can_dev->net);
1838 
1839 	of_can_transceiver(m_can_dev->net);
1840 
1841 	dev_info(m_can_dev->dev, "%s device registered (irq=%d, version=%d)\n",
1842 		 KBUILD_MODNAME, m_can_dev->net->irq, m_can_dev->version);
1843 
1844 	/* Probe finished
1845 	 * Stop clocks. They will be reactivated once the M_CAN device is opened
1846 	 */
1847 clk_disable:
1848 	m_can_clk_stop(m_can_dev);
1849 pm_runtime_fail:
1850 	if (ret) {
1851 		if (m_can_dev->pm_clock_support)
1852 			pm_runtime_disable(m_can_dev->dev);
1853 		free_candev(m_can_dev->net);
1854 	}
1855 
1856 	return ret;
1857 }
1858 EXPORT_SYMBOL_GPL(m_can_class_register);
1859 
1860 int m_can_class_suspend(struct device *dev)
1861 {
1862 	struct net_device *ndev = dev_get_drvdata(dev);
1863 	struct m_can_classdev *cdev = netdev_priv(ndev);
1864 
1865 	if (netif_running(ndev)) {
1866 		netif_stop_queue(ndev);
1867 		netif_device_detach(ndev);
1868 		m_can_stop(ndev);
1869 		m_can_clk_stop(cdev);
1870 	}
1871 
1872 	pinctrl_pm_select_sleep_state(dev);
1873 
1874 	cdev->can.state = CAN_STATE_SLEEPING;
1875 
1876 	return 0;
1877 }
1878 EXPORT_SYMBOL_GPL(m_can_class_suspend);
1879 
1880 int m_can_class_resume(struct device *dev)
1881 {
1882 	struct net_device *ndev = dev_get_drvdata(dev);
1883 	struct m_can_classdev *cdev = netdev_priv(ndev);
1884 
1885 	pinctrl_pm_select_default_state(dev);
1886 
1887 	cdev->can.state = CAN_STATE_ERROR_ACTIVE;
1888 
1889 	if (netif_running(ndev)) {
1890 		int ret;
1891 
1892 		ret = m_can_clk_start(cdev);
1893 		if (ret)
1894 			return ret;
1895 
1896 		m_can_init_ram(cdev);
1897 		m_can_start(ndev);
1898 		netif_device_attach(ndev);
1899 		netif_start_queue(ndev);
1900 	}
1901 
1902 	return 0;
1903 }
1904 EXPORT_SYMBOL_GPL(m_can_class_resume);
1905 
1906 void m_can_class_unregister(struct m_can_classdev *m_can_dev)
1907 {
1908 	unregister_candev(m_can_dev->net);
1909 
1910 	m_can_clk_stop(m_can_dev);
1911 
1912 	free_candev(m_can_dev->net);
1913 }
1914 EXPORT_SYMBOL_GPL(m_can_class_unregister);
1915 
1916 MODULE_AUTHOR("Dong Aisheng <b29396@freescale.com>");
1917 MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
1918 MODULE_LICENSE("GPL v2");
1919 MODULE_DESCRIPTION("CAN bus driver for Bosch M_CAN controller");
1920