1 /*
2 * flexcan.c - FLEXCAN CAN controller driver
3 *
4 * Copyright (c) 2005-2006 Varma Electronics Oy
5 * Copyright (c) 2009 Sascha Hauer, Pengutronix
6 * Copyright (c) 2010 Marc Kleine-Budde, Pengutronix
7 *
8 * Based on code originally by Andrey Volkov <avolkov@varma-el.com>
9 *
10 * LICENCE:
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation version 2.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 */
21
22 #include <linux/netdevice.h>
23 #include <linux/can.h>
24 #include <linux/can/dev.h>
25 #include <linux/can/error.h>
26 #include <linux/can/platform/flexcan.h>
27 #include <linux/clk.h>
28 #include <linux/delay.h>
29 #include <linux/if_arp.h>
30 #include <linux/if_ether.h>
31 #include <linux/interrupt.h>
32 #include <linux/io.h>
33 #include <linux/kernel.h>
34 #include <linux/list.h>
35 #include <linux/module.h>
36 #include <linux/of.h>
37 #include <linux/platform_device.h>
38
39 #define DRV_NAME "flexcan"
40
41 /* 8 for RX fifo and 2 error handling */
42 #define FLEXCAN_NAPI_WEIGHT (8 + 2)
43
44 /* FLEXCAN module configuration register (CANMCR) bits */
45 #define FLEXCAN_MCR_MDIS BIT(31)
46 #define FLEXCAN_MCR_FRZ BIT(30)
47 #define FLEXCAN_MCR_FEN BIT(29)
48 #define FLEXCAN_MCR_HALT BIT(28)
49 #define FLEXCAN_MCR_NOT_RDY BIT(27)
50 #define FLEXCAN_MCR_WAK_MSK BIT(26)
51 #define FLEXCAN_MCR_SOFTRST BIT(25)
52 #define FLEXCAN_MCR_FRZ_ACK BIT(24)
53 #define FLEXCAN_MCR_SUPV BIT(23)
54 #define FLEXCAN_MCR_SLF_WAK BIT(22)
55 #define FLEXCAN_MCR_WRN_EN BIT(21)
56 #define FLEXCAN_MCR_LPM_ACK BIT(20)
57 #define FLEXCAN_MCR_WAK_SRC BIT(19)
58 #define FLEXCAN_MCR_DOZE BIT(18)
59 #define FLEXCAN_MCR_SRX_DIS BIT(17)
60 #define FLEXCAN_MCR_BCC BIT(16)
61 #define FLEXCAN_MCR_LPRIO_EN BIT(13)
62 #define FLEXCAN_MCR_AEN BIT(12)
63 #define FLEXCAN_MCR_MAXMB(x) ((x) & 0xf)
64 #define FLEXCAN_MCR_IDAM_A (0 << 8)
65 #define FLEXCAN_MCR_IDAM_B (1 << 8)
66 #define FLEXCAN_MCR_IDAM_C (2 << 8)
67 #define FLEXCAN_MCR_IDAM_D (3 << 8)
68
69 /* FLEXCAN control register (CANCTRL) bits */
70 #define FLEXCAN_CTRL_PRESDIV(x) (((x) & 0xff) << 24)
71 #define FLEXCAN_CTRL_RJW(x) (((x) & 0x03) << 22)
72 #define FLEXCAN_CTRL_PSEG1(x) (((x) & 0x07) << 19)
73 #define FLEXCAN_CTRL_PSEG2(x) (((x) & 0x07) << 16)
74 #define FLEXCAN_CTRL_BOFF_MSK BIT(15)
75 #define FLEXCAN_CTRL_ERR_MSK BIT(14)
76 #define FLEXCAN_CTRL_CLK_SRC BIT(13)
77 #define FLEXCAN_CTRL_LPB BIT(12)
78 #define FLEXCAN_CTRL_TWRN_MSK BIT(11)
79 #define FLEXCAN_CTRL_RWRN_MSK BIT(10)
80 #define FLEXCAN_CTRL_SMP BIT(7)
81 #define FLEXCAN_CTRL_BOFF_REC BIT(6)
82 #define FLEXCAN_CTRL_TSYN BIT(5)
83 #define FLEXCAN_CTRL_LBUF BIT(4)
84 #define FLEXCAN_CTRL_LOM BIT(3)
85 #define FLEXCAN_CTRL_PROPSEG(x) ((x) & 0x07)
86 #define FLEXCAN_CTRL_ERR_BUS (FLEXCAN_CTRL_ERR_MSK)
87 #define FLEXCAN_CTRL_ERR_STATE \
88 (FLEXCAN_CTRL_TWRN_MSK | FLEXCAN_CTRL_RWRN_MSK | \
89 FLEXCAN_CTRL_BOFF_MSK)
90 #define FLEXCAN_CTRL_ERR_ALL \
91 (FLEXCAN_CTRL_ERR_BUS | FLEXCAN_CTRL_ERR_STATE)
92
93 /* FLEXCAN error and status register (ESR) bits */
94 #define FLEXCAN_ESR_TWRN_INT BIT(17)
95 #define FLEXCAN_ESR_RWRN_INT BIT(16)
96 #define FLEXCAN_ESR_BIT1_ERR BIT(15)
97 #define FLEXCAN_ESR_BIT0_ERR BIT(14)
98 #define FLEXCAN_ESR_ACK_ERR BIT(13)
99 #define FLEXCAN_ESR_CRC_ERR BIT(12)
100 #define FLEXCAN_ESR_FRM_ERR BIT(11)
101 #define FLEXCAN_ESR_STF_ERR BIT(10)
102 #define FLEXCAN_ESR_TX_WRN BIT(9)
103 #define FLEXCAN_ESR_RX_WRN BIT(8)
104 #define FLEXCAN_ESR_IDLE BIT(7)
105 #define FLEXCAN_ESR_TXRX BIT(6)
106 #define FLEXCAN_EST_FLT_CONF_SHIFT (4)
107 #define FLEXCAN_ESR_FLT_CONF_MASK (0x3 << FLEXCAN_EST_FLT_CONF_SHIFT)
108 #define FLEXCAN_ESR_FLT_CONF_ACTIVE (0x0 << FLEXCAN_EST_FLT_CONF_SHIFT)
109 #define FLEXCAN_ESR_FLT_CONF_PASSIVE (0x1 << FLEXCAN_EST_FLT_CONF_SHIFT)
110 #define FLEXCAN_ESR_BOFF_INT BIT(2)
111 #define FLEXCAN_ESR_ERR_INT BIT(1)
112 #define FLEXCAN_ESR_WAK_INT BIT(0)
113 #define FLEXCAN_ESR_ERR_BUS \
114 (FLEXCAN_ESR_BIT1_ERR | FLEXCAN_ESR_BIT0_ERR | \
115 FLEXCAN_ESR_ACK_ERR | FLEXCAN_ESR_CRC_ERR | \
116 FLEXCAN_ESR_FRM_ERR | FLEXCAN_ESR_STF_ERR)
117 #define FLEXCAN_ESR_ERR_STATE \
118 (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | FLEXCAN_ESR_BOFF_INT)
119 #define FLEXCAN_ESR_ERR_ALL \
120 (FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE)
121 #define FLEXCAN_ESR_ALL_INT \
122 (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
123 FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
124
125 /* FLEXCAN interrupt flag register (IFLAG) bits */
126 #define FLEXCAN_TX_BUF_ID 8
127 #define FLEXCAN_IFLAG_BUF(x) BIT(x)
128 #define FLEXCAN_IFLAG_RX_FIFO_OVERFLOW BIT(7)
129 #define FLEXCAN_IFLAG_RX_FIFO_WARN BIT(6)
130 #define FLEXCAN_IFLAG_RX_FIFO_AVAILABLE BIT(5)
131 #define FLEXCAN_IFLAG_DEFAULT \
132 (FLEXCAN_IFLAG_RX_FIFO_OVERFLOW | FLEXCAN_IFLAG_RX_FIFO_AVAILABLE | \
133 FLEXCAN_IFLAG_BUF(FLEXCAN_TX_BUF_ID))
134
135 /* FLEXCAN message buffers */
136 #define FLEXCAN_MB_CNT_CODE(x) (((x) & 0xf) << 24)
137 #define FLEXCAN_MB_CNT_SRR BIT(22)
138 #define FLEXCAN_MB_CNT_IDE BIT(21)
139 #define FLEXCAN_MB_CNT_RTR BIT(20)
140 #define FLEXCAN_MB_CNT_LENGTH(x) (((x) & 0xf) << 16)
141 #define FLEXCAN_MB_CNT_TIMESTAMP(x) ((x) & 0xffff)
142
143 #define FLEXCAN_MB_CODE_MASK (0xf0ffffff)
144
145 /* Structure of the message buffer */
146 struct flexcan_mb {
147 u32 can_ctrl;
148 u32 can_id;
149 u32 data[2];
150 };
151
152 /* Structure of the hardware registers */
153 struct flexcan_regs {
154 u32 mcr; /* 0x00 */
155 u32 ctrl; /* 0x04 */
156 u32 timer; /* 0x08 */
157 u32 _reserved1; /* 0x0c */
158 u32 rxgmask; /* 0x10 */
159 u32 rx14mask; /* 0x14 */
160 u32 rx15mask; /* 0x18 */
161 u32 ecr; /* 0x1c */
162 u32 esr; /* 0x20 */
163 u32 imask2; /* 0x24 */
164 u32 imask1; /* 0x28 */
165 u32 iflag2; /* 0x2c */
166 u32 iflag1; /* 0x30 */
167 u32 _reserved2[19];
168 struct flexcan_mb cantxfg[64];
169 };
170
171 struct flexcan_priv {
172 struct can_priv can;
173 struct net_device *dev;
174 struct napi_struct napi;
175
176 void __iomem *base;
177 u32 reg_esr;
178 u32 reg_ctrl_default;
179
180 struct clk *clk;
181 struct flexcan_platform_data *pdata;
182 };
183
184 static struct can_bittiming_const flexcan_bittiming_const = {
185 .name = DRV_NAME,
186 .tseg1_min = 4,
187 .tseg1_max = 16,
188 .tseg2_min = 2,
189 .tseg2_max = 8,
190 .sjw_max = 4,
191 .brp_min = 1,
192 .brp_max = 256,
193 .brp_inc = 1,
194 };
195
196 /*
197 * Abstract off the read/write for arm versus ppc.
198 */
199 #if defined(__BIG_ENDIAN)
flexcan_read(void __iomem * addr)200 static inline u32 flexcan_read(void __iomem *addr)
201 {
202 return in_be32(addr);
203 }
204
flexcan_write(u32 val,void __iomem * addr)205 static inline void flexcan_write(u32 val, void __iomem *addr)
206 {
207 out_be32(addr, val);
208 }
209 #else
flexcan_read(void __iomem * addr)210 static inline u32 flexcan_read(void __iomem *addr)
211 {
212 return readl(addr);
213 }
214
flexcan_write(u32 val,void __iomem * addr)215 static inline void flexcan_write(u32 val, void __iomem *addr)
216 {
217 writel(val, addr);
218 }
219 #endif
220
221 /*
222 * Swtich transceiver on or off
223 */
flexcan_transceiver_switch(const struct flexcan_priv * priv,int on)224 static void flexcan_transceiver_switch(const struct flexcan_priv *priv, int on)
225 {
226 if (priv->pdata && priv->pdata->transceiver_switch)
227 priv->pdata->transceiver_switch(on);
228 }
229
flexcan_has_and_handle_berr(const struct flexcan_priv * priv,u32 reg_esr)230 static inline int flexcan_has_and_handle_berr(const struct flexcan_priv *priv,
231 u32 reg_esr)
232 {
233 return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
234 (reg_esr & FLEXCAN_ESR_ERR_BUS);
235 }
236
flexcan_chip_enable(struct flexcan_priv * priv)237 static inline void flexcan_chip_enable(struct flexcan_priv *priv)
238 {
239 struct flexcan_regs __iomem *regs = priv->base;
240 u32 reg;
241
242 reg = flexcan_read(®s->mcr);
243 reg &= ~FLEXCAN_MCR_MDIS;
244 flexcan_write(reg, ®s->mcr);
245
246 udelay(10);
247 }
248
flexcan_chip_disable(struct flexcan_priv * priv)249 static inline void flexcan_chip_disable(struct flexcan_priv *priv)
250 {
251 struct flexcan_regs __iomem *regs = priv->base;
252 u32 reg;
253
254 reg = flexcan_read(®s->mcr);
255 reg |= FLEXCAN_MCR_MDIS;
256 flexcan_write(reg, ®s->mcr);
257 }
258
flexcan_get_berr_counter(const struct net_device * dev,struct can_berr_counter * bec)259 static int flexcan_get_berr_counter(const struct net_device *dev,
260 struct can_berr_counter *bec)
261 {
262 const struct flexcan_priv *priv = netdev_priv(dev);
263 struct flexcan_regs __iomem *regs = priv->base;
264 u32 reg = flexcan_read(®s->ecr);
265
266 bec->txerr = (reg >> 0) & 0xff;
267 bec->rxerr = (reg >> 8) & 0xff;
268
269 return 0;
270 }
271
flexcan_start_xmit(struct sk_buff * skb,struct net_device * dev)272 static int flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
273 {
274 const struct flexcan_priv *priv = netdev_priv(dev);
275 struct net_device_stats *stats = &dev->stats;
276 struct flexcan_regs __iomem *regs = priv->base;
277 struct can_frame *cf = (struct can_frame *)skb->data;
278 u32 can_id;
279 u32 ctrl = FLEXCAN_MB_CNT_CODE(0xc) | (cf->can_dlc << 16);
280
281 if (can_dropped_invalid_skb(dev, skb))
282 return NETDEV_TX_OK;
283
284 netif_stop_queue(dev);
285
286 if (cf->can_id & CAN_EFF_FLAG) {
287 can_id = cf->can_id & CAN_EFF_MASK;
288 ctrl |= FLEXCAN_MB_CNT_IDE | FLEXCAN_MB_CNT_SRR;
289 } else {
290 can_id = (cf->can_id & CAN_SFF_MASK) << 18;
291 }
292
293 if (cf->can_id & CAN_RTR_FLAG)
294 ctrl |= FLEXCAN_MB_CNT_RTR;
295
296 if (cf->can_dlc > 0) {
297 u32 data = be32_to_cpup((__be32 *)&cf->data[0]);
298 flexcan_write(data, ®s->cantxfg[FLEXCAN_TX_BUF_ID].data[0]);
299 }
300 if (cf->can_dlc > 3) {
301 u32 data = be32_to_cpup((__be32 *)&cf->data[4]);
302 flexcan_write(data, ®s->cantxfg[FLEXCAN_TX_BUF_ID].data[1]);
303 }
304
305 flexcan_write(can_id, ®s->cantxfg[FLEXCAN_TX_BUF_ID].can_id);
306 flexcan_write(ctrl, ®s->cantxfg[FLEXCAN_TX_BUF_ID].can_ctrl);
307
308 kfree_skb(skb);
309
310 /* tx_packets is incremented in flexcan_irq */
311 stats->tx_bytes += cf->can_dlc;
312
313 return NETDEV_TX_OK;
314 }
315
do_bus_err(struct net_device * dev,struct can_frame * cf,u32 reg_esr)316 static void do_bus_err(struct net_device *dev,
317 struct can_frame *cf, u32 reg_esr)
318 {
319 struct flexcan_priv *priv = netdev_priv(dev);
320 int rx_errors = 0, tx_errors = 0;
321
322 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
323
324 if (reg_esr & FLEXCAN_ESR_BIT1_ERR) {
325 dev_dbg(dev->dev.parent, "BIT1_ERR irq\n");
326 cf->data[2] |= CAN_ERR_PROT_BIT1;
327 tx_errors = 1;
328 }
329 if (reg_esr & FLEXCAN_ESR_BIT0_ERR) {
330 dev_dbg(dev->dev.parent, "BIT0_ERR irq\n");
331 cf->data[2] |= CAN_ERR_PROT_BIT0;
332 tx_errors = 1;
333 }
334 if (reg_esr & FLEXCAN_ESR_ACK_ERR) {
335 dev_dbg(dev->dev.parent, "ACK_ERR irq\n");
336 cf->can_id |= CAN_ERR_ACK;
337 cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
338 tx_errors = 1;
339 }
340 if (reg_esr & FLEXCAN_ESR_CRC_ERR) {
341 dev_dbg(dev->dev.parent, "CRC_ERR irq\n");
342 cf->data[2] |= CAN_ERR_PROT_BIT;
343 cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
344 rx_errors = 1;
345 }
346 if (reg_esr & FLEXCAN_ESR_FRM_ERR) {
347 dev_dbg(dev->dev.parent, "FRM_ERR irq\n");
348 cf->data[2] |= CAN_ERR_PROT_FORM;
349 rx_errors = 1;
350 }
351 if (reg_esr & FLEXCAN_ESR_STF_ERR) {
352 dev_dbg(dev->dev.parent, "STF_ERR irq\n");
353 cf->data[2] |= CAN_ERR_PROT_STUFF;
354 rx_errors = 1;
355 }
356
357 priv->can.can_stats.bus_error++;
358 if (rx_errors)
359 dev->stats.rx_errors++;
360 if (tx_errors)
361 dev->stats.tx_errors++;
362 }
363
flexcan_poll_bus_err(struct net_device * dev,u32 reg_esr)364 static int flexcan_poll_bus_err(struct net_device *dev, u32 reg_esr)
365 {
366 struct sk_buff *skb;
367 struct can_frame *cf;
368
369 skb = alloc_can_err_skb(dev, &cf);
370 if (unlikely(!skb))
371 return 0;
372
373 do_bus_err(dev, cf, reg_esr);
374 netif_receive_skb(skb);
375
376 dev->stats.rx_packets++;
377 dev->stats.rx_bytes += cf->can_dlc;
378
379 return 1;
380 }
381
do_state(struct net_device * dev,struct can_frame * cf,enum can_state new_state)382 static void do_state(struct net_device *dev,
383 struct can_frame *cf, enum can_state new_state)
384 {
385 struct flexcan_priv *priv = netdev_priv(dev);
386 struct can_berr_counter bec;
387
388 flexcan_get_berr_counter(dev, &bec);
389
390 switch (priv->can.state) {
391 case CAN_STATE_ERROR_ACTIVE:
392 /*
393 * from: ERROR_ACTIVE
394 * to : ERROR_WARNING, ERROR_PASSIVE, BUS_OFF
395 * => : there was a warning int
396 */
397 if (new_state >= CAN_STATE_ERROR_WARNING &&
398 new_state <= CAN_STATE_BUS_OFF) {
399 dev_dbg(dev->dev.parent, "Error Warning IRQ\n");
400 priv->can.can_stats.error_warning++;
401
402 cf->can_id |= CAN_ERR_CRTL;
403 cf->data[1] = (bec.txerr > bec.rxerr) ?
404 CAN_ERR_CRTL_TX_WARNING :
405 CAN_ERR_CRTL_RX_WARNING;
406 }
407 case CAN_STATE_ERROR_WARNING: /* fallthrough */
408 /*
409 * from: ERROR_ACTIVE, ERROR_WARNING
410 * to : ERROR_PASSIVE, BUS_OFF
411 * => : error passive int
412 */
413 if (new_state >= CAN_STATE_ERROR_PASSIVE &&
414 new_state <= CAN_STATE_BUS_OFF) {
415 dev_dbg(dev->dev.parent, "Error Passive IRQ\n");
416 priv->can.can_stats.error_passive++;
417
418 cf->can_id |= CAN_ERR_CRTL;
419 cf->data[1] = (bec.txerr > bec.rxerr) ?
420 CAN_ERR_CRTL_TX_PASSIVE :
421 CAN_ERR_CRTL_RX_PASSIVE;
422 }
423 break;
424 case CAN_STATE_BUS_OFF:
425 dev_err(dev->dev.parent,
426 "BUG! hardware recovered automatically from BUS_OFF\n");
427 break;
428 default:
429 break;
430 }
431
432 /* process state changes depending on the new state */
433 switch (new_state) {
434 case CAN_STATE_ERROR_ACTIVE:
435 dev_dbg(dev->dev.parent, "Error Active\n");
436 cf->can_id |= CAN_ERR_PROT;
437 cf->data[2] = CAN_ERR_PROT_ACTIVE;
438 break;
439 case CAN_STATE_BUS_OFF:
440 cf->can_id |= CAN_ERR_BUSOFF;
441 can_bus_off(dev);
442 break;
443 default:
444 break;
445 }
446 }
447
flexcan_poll_state(struct net_device * dev,u32 reg_esr)448 static int flexcan_poll_state(struct net_device *dev, u32 reg_esr)
449 {
450 struct flexcan_priv *priv = netdev_priv(dev);
451 struct sk_buff *skb;
452 struct can_frame *cf;
453 enum can_state new_state;
454 int flt;
455
456 flt = reg_esr & FLEXCAN_ESR_FLT_CONF_MASK;
457 if (likely(flt == FLEXCAN_ESR_FLT_CONF_ACTIVE)) {
458 if (likely(!(reg_esr & (FLEXCAN_ESR_TX_WRN |
459 FLEXCAN_ESR_RX_WRN))))
460 new_state = CAN_STATE_ERROR_ACTIVE;
461 else
462 new_state = CAN_STATE_ERROR_WARNING;
463 } else if (unlikely(flt == FLEXCAN_ESR_FLT_CONF_PASSIVE))
464 new_state = CAN_STATE_ERROR_PASSIVE;
465 else
466 new_state = CAN_STATE_BUS_OFF;
467
468 /* state hasn't changed */
469 if (likely(new_state == priv->can.state))
470 return 0;
471
472 skb = alloc_can_err_skb(dev, &cf);
473 if (unlikely(!skb))
474 return 0;
475
476 do_state(dev, cf, new_state);
477 priv->can.state = new_state;
478 netif_receive_skb(skb);
479
480 dev->stats.rx_packets++;
481 dev->stats.rx_bytes += cf->can_dlc;
482
483 return 1;
484 }
485
flexcan_read_fifo(const struct net_device * dev,struct can_frame * cf)486 static void flexcan_read_fifo(const struct net_device *dev,
487 struct can_frame *cf)
488 {
489 const struct flexcan_priv *priv = netdev_priv(dev);
490 struct flexcan_regs __iomem *regs = priv->base;
491 struct flexcan_mb __iomem *mb = ®s->cantxfg[0];
492 u32 reg_ctrl, reg_id;
493
494 reg_ctrl = flexcan_read(&mb->can_ctrl);
495 reg_id = flexcan_read(&mb->can_id);
496 if (reg_ctrl & FLEXCAN_MB_CNT_IDE)
497 cf->can_id = ((reg_id >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
498 else
499 cf->can_id = (reg_id >> 18) & CAN_SFF_MASK;
500
501 if (reg_ctrl & FLEXCAN_MB_CNT_RTR)
502 cf->can_id |= CAN_RTR_FLAG;
503 cf->can_dlc = get_can_dlc((reg_ctrl >> 16) & 0xf);
504
505 *(__be32 *)(cf->data + 0) = cpu_to_be32(flexcan_read(&mb->data[0]));
506 *(__be32 *)(cf->data + 4) = cpu_to_be32(flexcan_read(&mb->data[1]));
507
508 /* mark as read */
509 flexcan_write(FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, ®s->iflag1);
510 flexcan_read(®s->timer);
511 }
512
flexcan_read_frame(struct net_device * dev)513 static int flexcan_read_frame(struct net_device *dev)
514 {
515 struct net_device_stats *stats = &dev->stats;
516 struct can_frame *cf;
517 struct sk_buff *skb;
518
519 skb = alloc_can_skb(dev, &cf);
520 if (unlikely(!skb)) {
521 stats->rx_dropped++;
522 return 0;
523 }
524
525 flexcan_read_fifo(dev, cf);
526 netif_receive_skb(skb);
527
528 stats->rx_packets++;
529 stats->rx_bytes += cf->can_dlc;
530
531 return 1;
532 }
533
flexcan_poll(struct napi_struct * napi,int quota)534 static int flexcan_poll(struct napi_struct *napi, int quota)
535 {
536 struct net_device *dev = napi->dev;
537 const struct flexcan_priv *priv = netdev_priv(dev);
538 struct flexcan_regs __iomem *regs = priv->base;
539 u32 reg_iflag1, reg_esr;
540 int work_done = 0;
541
542 /*
543 * The error bits are cleared on read,
544 * use saved value from irq handler.
545 */
546 reg_esr = flexcan_read(®s->esr) | priv->reg_esr;
547
548 /* handle state changes */
549 work_done += flexcan_poll_state(dev, reg_esr);
550
551 /* handle RX-FIFO */
552 reg_iflag1 = flexcan_read(®s->iflag1);
553 while (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE &&
554 work_done < quota) {
555 work_done += flexcan_read_frame(dev);
556 reg_iflag1 = flexcan_read(®s->iflag1);
557 }
558
559 /* report bus errors */
560 if (flexcan_has_and_handle_berr(priv, reg_esr) && work_done < quota)
561 work_done += flexcan_poll_bus_err(dev, reg_esr);
562
563 if (work_done < quota) {
564 napi_complete(napi);
565 /* enable IRQs */
566 flexcan_write(FLEXCAN_IFLAG_DEFAULT, ®s->imask1);
567 flexcan_write(priv->reg_ctrl_default, ®s->ctrl);
568 }
569
570 return work_done;
571 }
572
flexcan_irq(int irq,void * dev_id)573 static irqreturn_t flexcan_irq(int irq, void *dev_id)
574 {
575 struct net_device *dev = dev_id;
576 struct net_device_stats *stats = &dev->stats;
577 struct flexcan_priv *priv = netdev_priv(dev);
578 struct flexcan_regs __iomem *regs = priv->base;
579 u32 reg_iflag1, reg_esr;
580
581 reg_iflag1 = flexcan_read(®s->iflag1);
582 reg_esr = flexcan_read(®s->esr);
583 /* ACK all bus error and state change IRQ sources */
584 if (reg_esr & FLEXCAN_ESR_ALL_INT)
585 flexcan_write(reg_esr & FLEXCAN_ESR_ALL_INT, ®s->esr);
586
587 /*
588 * schedule NAPI in case of:
589 * - rx IRQ
590 * - state change IRQ
591 * - bus error IRQ and bus error reporting is activated
592 */
593 if ((reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) ||
594 (reg_esr & FLEXCAN_ESR_ERR_STATE) ||
595 flexcan_has_and_handle_berr(priv, reg_esr)) {
596 /*
597 * The error bits are cleared on read,
598 * save them for later use.
599 */
600 priv->reg_esr = reg_esr & FLEXCAN_ESR_ERR_BUS;
601 flexcan_write(FLEXCAN_IFLAG_DEFAULT &
602 ~FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, ®s->imask1);
603 flexcan_write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
604 ®s->ctrl);
605 napi_schedule(&priv->napi);
606 }
607
608 /* FIFO overflow */
609 if (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_OVERFLOW) {
610 flexcan_write(FLEXCAN_IFLAG_RX_FIFO_OVERFLOW, ®s->iflag1);
611 dev->stats.rx_over_errors++;
612 dev->stats.rx_errors++;
613 }
614
615 /* transmission complete interrupt */
616 if (reg_iflag1 & (1 << FLEXCAN_TX_BUF_ID)) {
617 /* tx_bytes is incremented in flexcan_start_xmit */
618 stats->tx_packets++;
619 flexcan_write((1 << FLEXCAN_TX_BUF_ID), ®s->iflag1);
620 netif_wake_queue(dev);
621 }
622
623 return IRQ_HANDLED;
624 }
625
flexcan_set_bittiming(struct net_device * dev)626 static void flexcan_set_bittiming(struct net_device *dev)
627 {
628 const struct flexcan_priv *priv = netdev_priv(dev);
629 const struct can_bittiming *bt = &priv->can.bittiming;
630 struct flexcan_regs __iomem *regs = priv->base;
631 u32 reg;
632
633 reg = flexcan_read(®s->ctrl);
634 reg &= ~(FLEXCAN_CTRL_PRESDIV(0xff) |
635 FLEXCAN_CTRL_RJW(0x3) |
636 FLEXCAN_CTRL_PSEG1(0x7) |
637 FLEXCAN_CTRL_PSEG2(0x7) |
638 FLEXCAN_CTRL_PROPSEG(0x7) |
639 FLEXCAN_CTRL_LPB |
640 FLEXCAN_CTRL_SMP |
641 FLEXCAN_CTRL_LOM);
642
643 reg |= FLEXCAN_CTRL_PRESDIV(bt->brp - 1) |
644 FLEXCAN_CTRL_PSEG1(bt->phase_seg1 - 1) |
645 FLEXCAN_CTRL_PSEG2(bt->phase_seg2 - 1) |
646 FLEXCAN_CTRL_RJW(bt->sjw - 1) |
647 FLEXCAN_CTRL_PROPSEG(bt->prop_seg - 1);
648
649 if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
650 reg |= FLEXCAN_CTRL_LPB;
651 if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
652 reg |= FLEXCAN_CTRL_LOM;
653 if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
654 reg |= FLEXCAN_CTRL_SMP;
655
656 dev_info(dev->dev.parent, "writing ctrl=0x%08x\n", reg);
657 flexcan_write(reg, ®s->ctrl);
658
659 /* print chip status */
660 dev_dbg(dev->dev.parent, "%s: mcr=0x%08x ctrl=0x%08x\n", __func__,
661 flexcan_read(®s->mcr), flexcan_read(®s->ctrl));
662 }
663
664 /*
665 * flexcan_chip_start
666 *
667 * this functions is entered with clocks enabled
668 *
669 */
flexcan_chip_start(struct net_device * dev)670 static int flexcan_chip_start(struct net_device *dev)
671 {
672 struct flexcan_priv *priv = netdev_priv(dev);
673 struct flexcan_regs __iomem *regs = priv->base;
674 unsigned int i;
675 int err;
676 u32 reg_mcr, reg_ctrl;
677
678 /* enable module */
679 flexcan_chip_enable(priv);
680
681 /* soft reset */
682 flexcan_write(FLEXCAN_MCR_SOFTRST, ®s->mcr);
683 udelay(10);
684
685 reg_mcr = flexcan_read(®s->mcr);
686 if (reg_mcr & FLEXCAN_MCR_SOFTRST) {
687 dev_err(dev->dev.parent,
688 "Failed to softreset can module (mcr=0x%08x)\n",
689 reg_mcr);
690 err = -ENODEV;
691 goto out;
692 }
693
694 flexcan_set_bittiming(dev);
695
696 /*
697 * MCR
698 *
699 * enable freeze
700 * enable fifo
701 * halt now
702 * only supervisor access
703 * enable warning int
704 * choose format C
705 *
706 */
707 reg_mcr = flexcan_read(®s->mcr);
708 reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_FEN | FLEXCAN_MCR_HALT |
709 FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN |
710 FLEXCAN_MCR_IDAM_C;
711 dev_dbg(dev->dev.parent, "%s: writing mcr=0x%08x", __func__, reg_mcr);
712 flexcan_write(reg_mcr, ®s->mcr);
713
714 /*
715 * CTRL
716 *
717 * disable timer sync feature
718 *
719 * disable auto busoff recovery
720 * transmit lowest buffer first
721 *
722 * enable tx and rx warning interrupt
723 * enable bus off interrupt
724 * (== FLEXCAN_CTRL_ERR_STATE)
725 *
726 * _note_: we enable the "error interrupt"
727 * (FLEXCAN_CTRL_ERR_MSK), too. Otherwise we don't get any
728 * warning or bus passive interrupts.
729 */
730 reg_ctrl = flexcan_read(®s->ctrl);
731 reg_ctrl &= ~FLEXCAN_CTRL_TSYN;
732 reg_ctrl |= FLEXCAN_CTRL_BOFF_REC | FLEXCAN_CTRL_LBUF |
733 FLEXCAN_CTRL_ERR_STATE | FLEXCAN_CTRL_ERR_MSK;
734
735 /* save for later use */
736 priv->reg_ctrl_default = reg_ctrl;
737 dev_dbg(dev->dev.parent, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
738 flexcan_write(reg_ctrl, ®s->ctrl);
739
740 for (i = 0; i < ARRAY_SIZE(regs->cantxfg); i++) {
741 flexcan_write(0, ®s->cantxfg[i].can_ctrl);
742 flexcan_write(0, ®s->cantxfg[i].can_id);
743 flexcan_write(0, ®s->cantxfg[i].data[0]);
744 flexcan_write(0, ®s->cantxfg[i].data[1]);
745
746 /* put MB into rx queue */
747 flexcan_write(FLEXCAN_MB_CNT_CODE(0x4),
748 ®s->cantxfg[i].can_ctrl);
749 }
750
751 /* acceptance mask/acceptance code (accept everything) */
752 flexcan_write(0x0, ®s->rxgmask);
753 flexcan_write(0x0, ®s->rx14mask);
754 flexcan_write(0x0, ®s->rx15mask);
755
756 flexcan_transceiver_switch(priv, 1);
757
758 /* synchronize with the can bus */
759 reg_mcr = flexcan_read(®s->mcr);
760 reg_mcr &= ~FLEXCAN_MCR_HALT;
761 flexcan_write(reg_mcr, ®s->mcr);
762
763 priv->can.state = CAN_STATE_ERROR_ACTIVE;
764
765 /* enable FIFO interrupts */
766 flexcan_write(FLEXCAN_IFLAG_DEFAULT, ®s->imask1);
767
768 /* print chip status */
769 dev_dbg(dev->dev.parent, "%s: reading mcr=0x%08x ctrl=0x%08x\n",
770 __func__, flexcan_read(®s->mcr), flexcan_read(®s->ctrl));
771
772 return 0;
773
774 out:
775 flexcan_chip_disable(priv);
776 return err;
777 }
778
779 /*
780 * flexcan_chip_stop
781 *
782 * this functions is entered with clocks enabled
783 *
784 */
flexcan_chip_stop(struct net_device * dev)785 static void flexcan_chip_stop(struct net_device *dev)
786 {
787 struct flexcan_priv *priv = netdev_priv(dev);
788 struct flexcan_regs __iomem *regs = priv->base;
789 u32 reg;
790
791 /* Disable all interrupts */
792 flexcan_write(0, ®s->imask1);
793
794 /* Disable + halt module */
795 reg = flexcan_read(®s->mcr);
796 reg |= FLEXCAN_MCR_MDIS | FLEXCAN_MCR_HALT;
797 flexcan_write(reg, ®s->mcr);
798
799 flexcan_transceiver_switch(priv, 0);
800 priv->can.state = CAN_STATE_STOPPED;
801
802 return;
803 }
804
flexcan_open(struct net_device * dev)805 static int flexcan_open(struct net_device *dev)
806 {
807 struct flexcan_priv *priv = netdev_priv(dev);
808 int err;
809
810 clk_prepare_enable(priv->clk);
811
812 err = open_candev(dev);
813 if (err)
814 goto out;
815
816 err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
817 if (err)
818 goto out_close;
819
820 /* start chip and queuing */
821 err = flexcan_chip_start(dev);
822 if (err)
823 goto out_close;
824 napi_enable(&priv->napi);
825 netif_start_queue(dev);
826
827 return 0;
828
829 out_close:
830 close_candev(dev);
831 out:
832 clk_disable_unprepare(priv->clk);
833
834 return err;
835 }
836
flexcan_close(struct net_device * dev)837 static int flexcan_close(struct net_device *dev)
838 {
839 struct flexcan_priv *priv = netdev_priv(dev);
840
841 netif_stop_queue(dev);
842 napi_disable(&priv->napi);
843 flexcan_chip_stop(dev);
844
845 free_irq(dev->irq, dev);
846 clk_disable_unprepare(priv->clk);
847
848 close_candev(dev);
849
850 return 0;
851 }
852
flexcan_set_mode(struct net_device * dev,enum can_mode mode)853 static int flexcan_set_mode(struct net_device *dev, enum can_mode mode)
854 {
855 int err;
856
857 switch (mode) {
858 case CAN_MODE_START:
859 err = flexcan_chip_start(dev);
860 if (err)
861 return err;
862
863 netif_wake_queue(dev);
864 break;
865
866 default:
867 return -EOPNOTSUPP;
868 }
869
870 return 0;
871 }
872
873 static const struct net_device_ops flexcan_netdev_ops = {
874 .ndo_open = flexcan_open,
875 .ndo_stop = flexcan_close,
876 .ndo_start_xmit = flexcan_start_xmit,
877 };
878
register_flexcandev(struct net_device * dev)879 static int __devinit register_flexcandev(struct net_device *dev)
880 {
881 struct flexcan_priv *priv = netdev_priv(dev);
882 struct flexcan_regs __iomem *regs = priv->base;
883 u32 reg, err;
884
885 clk_prepare_enable(priv->clk);
886
887 /* select "bus clock", chip must be disabled */
888 flexcan_chip_disable(priv);
889 reg = flexcan_read(®s->ctrl);
890 reg |= FLEXCAN_CTRL_CLK_SRC;
891 flexcan_write(reg, ®s->ctrl);
892
893 flexcan_chip_enable(priv);
894
895 /* set freeze, halt and activate FIFO, restrict register access */
896 reg = flexcan_read(®s->mcr);
897 reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT |
898 FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV;
899 flexcan_write(reg, ®s->mcr);
900
901 /*
902 * Currently we only support newer versions of this core
903 * featuring a RX FIFO. Older cores found on some Coldfire
904 * derivates are not yet supported.
905 */
906 reg = flexcan_read(®s->mcr);
907 if (!(reg & FLEXCAN_MCR_FEN)) {
908 dev_err(dev->dev.parent,
909 "Could not enable RX FIFO, unsupported core\n");
910 err = -ENODEV;
911 goto out;
912 }
913
914 err = register_candev(dev);
915
916 out:
917 /* disable core and turn off clocks */
918 flexcan_chip_disable(priv);
919 clk_disable_unprepare(priv->clk);
920
921 return err;
922 }
923
unregister_flexcandev(struct net_device * dev)924 static void __devexit unregister_flexcandev(struct net_device *dev)
925 {
926 unregister_candev(dev);
927 }
928
flexcan_probe(struct platform_device * pdev)929 static int __devinit flexcan_probe(struct platform_device *pdev)
930 {
931 struct net_device *dev;
932 struct flexcan_priv *priv;
933 struct resource *mem;
934 struct clk *clk = NULL;
935 void __iomem *base;
936 resource_size_t mem_size;
937 int err, irq;
938 u32 clock_freq = 0;
939
940 if (pdev->dev.of_node) {
941 const u32 *clock_freq_p;
942
943 clock_freq_p = of_get_property(pdev->dev.of_node,
944 "clock-frequency", NULL);
945 if (clock_freq_p)
946 clock_freq = *clock_freq_p;
947 }
948
949 if (!clock_freq) {
950 clk = clk_get(&pdev->dev, NULL);
951 if (IS_ERR(clk)) {
952 dev_err(&pdev->dev, "no clock defined\n");
953 err = PTR_ERR(clk);
954 goto failed_clock;
955 }
956 clock_freq = clk_get_rate(clk);
957 }
958
959 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
960 irq = platform_get_irq(pdev, 0);
961 if (!mem || irq <= 0) {
962 err = -ENODEV;
963 goto failed_get;
964 }
965
966 mem_size = resource_size(mem);
967 if (!request_mem_region(mem->start, mem_size, pdev->name)) {
968 err = -EBUSY;
969 goto failed_get;
970 }
971
972 base = ioremap(mem->start, mem_size);
973 if (!base) {
974 err = -ENOMEM;
975 goto failed_map;
976 }
977
978 dev = alloc_candev(sizeof(struct flexcan_priv), 0);
979 if (!dev) {
980 err = -ENOMEM;
981 goto failed_alloc;
982 }
983
984 dev->netdev_ops = &flexcan_netdev_ops;
985 dev->irq = irq;
986 dev->flags |= IFF_ECHO; /* we support local echo in hardware */
987
988 priv = netdev_priv(dev);
989 priv->can.clock.freq = clock_freq;
990 priv->can.bittiming_const = &flexcan_bittiming_const;
991 priv->can.do_set_mode = flexcan_set_mode;
992 priv->can.do_get_berr_counter = flexcan_get_berr_counter;
993 priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
994 CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_3_SAMPLES |
995 CAN_CTRLMODE_BERR_REPORTING;
996 priv->base = base;
997 priv->dev = dev;
998 priv->clk = clk;
999 priv->pdata = pdev->dev.platform_data;
1000
1001 netif_napi_add(dev, &priv->napi, flexcan_poll, FLEXCAN_NAPI_WEIGHT);
1002
1003 dev_set_drvdata(&pdev->dev, dev);
1004 SET_NETDEV_DEV(dev, &pdev->dev);
1005
1006 err = register_flexcandev(dev);
1007 if (err) {
1008 dev_err(&pdev->dev, "registering netdev failed\n");
1009 goto failed_register;
1010 }
1011
1012 dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
1013 priv->base, dev->irq);
1014
1015 return 0;
1016
1017 failed_register:
1018 free_candev(dev);
1019 failed_alloc:
1020 iounmap(base);
1021 failed_map:
1022 release_mem_region(mem->start, mem_size);
1023 failed_get:
1024 if (clk)
1025 clk_put(clk);
1026 failed_clock:
1027 return err;
1028 }
1029
flexcan_remove(struct platform_device * pdev)1030 static int __devexit flexcan_remove(struct platform_device *pdev)
1031 {
1032 struct net_device *dev = platform_get_drvdata(pdev);
1033 struct flexcan_priv *priv = netdev_priv(dev);
1034 struct resource *mem;
1035
1036 unregister_flexcandev(dev);
1037 platform_set_drvdata(pdev, NULL);
1038 iounmap(priv->base);
1039
1040 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1041 release_mem_region(mem->start, resource_size(mem));
1042
1043 if (priv->clk)
1044 clk_put(priv->clk);
1045
1046 free_candev(dev);
1047
1048 return 0;
1049 }
1050
1051 static struct of_device_id flexcan_of_match[] = {
1052 {
1053 .compatible = "fsl,p1010-flexcan",
1054 },
1055 {},
1056 };
1057
1058 static struct platform_driver flexcan_driver = {
1059 .driver = {
1060 .name = DRV_NAME,
1061 .owner = THIS_MODULE,
1062 .of_match_table = flexcan_of_match,
1063 },
1064 .probe = flexcan_probe,
1065 .remove = __devexit_p(flexcan_remove),
1066 };
1067
1068 module_platform_driver(flexcan_driver);
1069
1070 MODULE_AUTHOR("Sascha Hauer <kernel@pengutronix.de>, "
1071 "Marc Kleine-Budde <kernel@pengutronix.de>");
1072 MODULE_LICENSE("GPL v2");
1073 MODULE_DESCRIPTION("CAN port driver for flexcan based chip");
1074