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1/*
2 * CAN bus driver for Microchip 251x CAN Controller with SPI Interface
3 *
4 * MCP2510 support and bug fixes by Christian Pellegrin
5 * <chripell@evolware.org>
6 *
7 * Copyright 2009 Christian Pellegrin EVOL S.r.l.
8 *
9 * Copyright 2007 Raymarine UK, Ltd. All Rights Reserved.
10 * Written under contract by:
11 * Chris Elston, Katalix Systems, Ltd.
12 *
13 * Based on Microchip MCP251x CAN controller driver written by
14 * David Vrabel, Copyright 2006 Arcom Control Systems Ltd.
15 *
16 * Based on CAN bus driver for the CCAN controller written by
17 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix
18 * - Simon Kallweit, intefo AG
19 * Copyright 2007
20 *
21 * This program is free software; you can redistribute it and/or modify
22 * it under the terms of the version 2 of the GNU General Public License
23 * as published by the Free Software Foundation
24 *
25 * This program is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
28 * GNU General Public License for more details.
29 *
30 * You should have received a copy of the GNU General Public License
31 * along with this program; if not, write to the Free Software
32 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
33 *
34 *
35 *
36 * Your platform definition file should specify something like:
37 *
38 * static struct mcp251x_platform_data mcp251x_info = {
39 * .oscillator_frequency = 8000000,
40 * .board_specific_setup = &mcp251x_setup,
41 * .power_enable = mcp251x_power_enable,
42 * .transceiver_enable = NULL,
43 * };
44 *
45 * static struct spi_board_info spi_board_info[] = {
46 * {
47 * .modalias = "mcp2510",
48 * // or "mcp2515" depending on your controller
49 * .platform_data = &mcp251x_info,
50 * .irq = IRQ_EINT13,
51 * .max_speed_hz = 2*1000*1000,
52 * .chip_select = 2,
53 * },
54 * };
55 *
56 * Please see mcp251x.h for a description of the fields in
57 * struct mcp251x_platform_data.
58 *
59 */
60
61#include <linux/can/core.h>
62#include <linux/can/dev.h>
63#include <linux/can/platform/mcp251x.h>
64#include <linux/completion.h>
65#include <linux/delay.h>
66#include <linux/device.h>
67#include <linux/dma-mapping.h>
68#include <linux/freezer.h>
69#include <linux/interrupt.h>
70#include <linux/io.h>
71#include <linux/kernel.h>
72#include <linux/module.h>
73#include <linux/netdevice.h>
74#include <linux/platform_device.h>
75#include <linux/slab.h>
76#include <linux/spi/spi.h>
77#include <linux/uaccess.h>
78
79/* SPI interface instruction set */
80#define INSTRUCTION_WRITE 0x02
81#define INSTRUCTION_READ 0x03
82#define INSTRUCTION_BIT_MODIFY 0x05
83#define INSTRUCTION_LOAD_TXB(n) (0x40 + 2 * (n))
84#define INSTRUCTION_READ_RXB(n) (((n) == 0) ? 0x90 : 0x94)
85#define INSTRUCTION_RESET 0xC0
86#define RTS_TXB0 0x01
87#define RTS_TXB1 0x02
88#define RTS_TXB2 0x04
89#define INSTRUCTION_RTS(n) (0x80 | ((n) & 0x07))
90
91
92/* MPC251x registers */
93#define CANSTAT 0x0e
94#define CANCTRL 0x0f
95# define CANCTRL_REQOP_MASK 0xe0
96# define CANCTRL_REQOP_CONF 0x80
97# define CANCTRL_REQOP_LISTEN_ONLY 0x60
98# define CANCTRL_REQOP_LOOPBACK 0x40
99# define CANCTRL_REQOP_SLEEP 0x20
100# define CANCTRL_REQOP_NORMAL 0x00
101# define CANCTRL_OSM 0x08
102# define CANCTRL_ABAT 0x10
103#define TEC 0x1c
104#define REC 0x1d
105#define CNF1 0x2a
106# define CNF1_SJW_SHIFT 6
107#define CNF2 0x29
108# define CNF2_BTLMODE 0x80
109# define CNF2_SAM 0x40
110# define CNF2_PS1_SHIFT 3
111#define CNF3 0x28
112# define CNF3_SOF 0x08
113# define CNF3_WAKFIL 0x04
114# define CNF3_PHSEG2_MASK 0x07
115#define CANINTE 0x2b
116# define CANINTE_MERRE 0x80
117# define CANINTE_WAKIE 0x40
118# define CANINTE_ERRIE 0x20
119# define CANINTE_TX2IE 0x10
120# define CANINTE_TX1IE 0x08
121# define CANINTE_TX0IE 0x04
122# define CANINTE_RX1IE 0x02
123# define CANINTE_RX0IE 0x01
124#define CANINTF 0x2c
125# define CANINTF_MERRF 0x80
126# define CANINTF_WAKIF 0x40
127# define CANINTF_ERRIF 0x20
128# define CANINTF_TX2IF 0x10
129# define CANINTF_TX1IF 0x08
130# define CANINTF_TX0IF 0x04
131# define CANINTF_RX1IF 0x02
132# define CANINTF_RX0IF 0x01
133# define CANINTF_RX (CANINTF_RX0IF | CANINTF_RX1IF)
134# define CANINTF_TX (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)
135# define CANINTF_ERR (CANINTF_ERRIF)
136#define EFLG 0x2d
137# define EFLG_EWARN 0x01
138# define EFLG_RXWAR 0x02
139# define EFLG_TXWAR 0x04
140# define EFLG_RXEP 0x08
141# define EFLG_TXEP 0x10
142# define EFLG_TXBO 0x20
143# define EFLG_RX0OVR 0x40
144# define EFLG_RX1OVR 0x80
145#define TXBCTRL(n) (((n) * 0x10) + 0x30 + TXBCTRL_OFF)
146# define TXBCTRL_ABTF 0x40
147# define TXBCTRL_MLOA 0x20
148# define TXBCTRL_TXERR 0x10
149# define TXBCTRL_TXREQ 0x08
150#define TXBSIDH(n) (((n) * 0x10) + 0x30 + TXBSIDH_OFF)
151# define SIDH_SHIFT 3
152#define TXBSIDL(n) (((n) * 0x10) + 0x30 + TXBSIDL_OFF)
153# define SIDL_SID_MASK 7
154# define SIDL_SID_SHIFT 5
155# define SIDL_EXIDE_SHIFT 3
156# define SIDL_EID_SHIFT 16
157# define SIDL_EID_MASK 3
158#define TXBEID8(n) (((n) * 0x10) + 0x30 + TXBEID8_OFF)
159#define TXBEID0(n) (((n) * 0x10) + 0x30 + TXBEID0_OFF)
160#define TXBDLC(n) (((n) * 0x10) + 0x30 + TXBDLC_OFF)
161# define DLC_RTR_SHIFT 6
162#define TXBCTRL_OFF 0
163#define TXBSIDH_OFF 1
164#define TXBSIDL_OFF 2
165#define TXBEID8_OFF 3
166#define TXBEID0_OFF 4
167#define TXBDLC_OFF 5
168#define TXBDAT_OFF 6
169#define RXBCTRL(n) (((n) * 0x10) + 0x60 + RXBCTRL_OFF)
170# define RXBCTRL_BUKT 0x04
171# define RXBCTRL_RXM0 0x20
172# define RXBCTRL_RXM1 0x40
173#define RXBSIDH(n) (((n) * 0x10) + 0x60 + RXBSIDH_OFF)
174# define RXBSIDH_SHIFT 3
175#define RXBSIDL(n) (((n) * 0x10) + 0x60 + RXBSIDL_OFF)
176# define RXBSIDL_IDE 0x08
177# define RXBSIDL_SRR 0x10
178# define RXBSIDL_EID 3
179# define RXBSIDL_SHIFT 5
180#define RXBEID8(n) (((n) * 0x10) + 0x60 + RXBEID8_OFF)
181#define RXBEID0(n) (((n) * 0x10) + 0x60 + RXBEID0_OFF)
182#define RXBDLC(n) (((n) * 0x10) + 0x60 + RXBDLC_OFF)
183# define RXBDLC_LEN_MASK 0x0f
184# define RXBDLC_RTR 0x40
185#define RXBCTRL_OFF 0
186#define RXBSIDH_OFF 1
187#define RXBSIDL_OFF 2
188#define RXBEID8_OFF 3
189#define RXBEID0_OFF 4
190#define RXBDLC_OFF 5
191#define RXBDAT_OFF 6
192#define RXFSIDH(n) ((n) * 4)
193#define RXFSIDL(n) ((n) * 4 + 1)
194#define RXFEID8(n) ((n) * 4 + 2)
195#define RXFEID0(n) ((n) * 4 + 3)
196#define RXMSIDH(n) ((n) * 4 + 0x20)
197#define RXMSIDL(n) ((n) * 4 + 0x21)
198#define RXMEID8(n) ((n) * 4 + 0x22)
199#define RXMEID0(n) ((n) * 4 + 0x23)
200
201#define GET_BYTE(val, byte) \
202 (((val) >> ((byte) * 8)) & 0xff)
203#define SET_BYTE(val, byte) \
204 (((val) & 0xff) << ((byte) * 8))
205
206/*
207 * Buffer size required for the largest SPI transfer (i.e., reading a
208 * frame)
209 */
210#define CAN_FRAME_MAX_DATA_LEN 8
211#define SPI_TRANSFER_BUF_LEN (6 + CAN_FRAME_MAX_DATA_LEN)
212#define CAN_FRAME_MAX_BITS 128
213
214#define TX_ECHO_SKB_MAX 1
215
216#define DEVICE_NAME "mcp251x"
217
218static int mcp251x_enable_dma; /* Enable SPI DMA. Default: 0 (Off) */
219module_param(mcp251x_enable_dma, int, S_IRUGO);
220MODULE_PARM_DESC(mcp251x_enable_dma, "Enable SPI DMA. Default: 0 (Off)");
221
222static struct can_bittiming_const mcp251x_bittiming_const = {
223 .name = DEVICE_NAME,
224 .tseg1_min = 3,
225 .tseg1_max = 16,
226 .tseg2_min = 2,
227 .tseg2_max = 8,
228 .sjw_max = 4,
229 .brp_min = 1,
230 .brp_max = 64,
231 .brp_inc = 1,
232};
233
234enum mcp251x_model {
235 CAN_MCP251X_MCP2510 = 0x2510,
236 CAN_MCP251X_MCP2515 = 0x2515,
237};
238
239struct mcp251x_priv {
240 struct can_priv can;
241 struct net_device *net;
242 struct spi_device *spi;
243 enum mcp251x_model model;
244
245 struct mutex mcp_lock; /* SPI device lock */
246
247 u8 *spi_tx_buf;
248 u8 *spi_rx_buf;
249 dma_addr_t spi_tx_dma;
250 dma_addr_t spi_rx_dma;
251
252 struct sk_buff *tx_skb;
253 int tx_len;
254
255 struct workqueue_struct *wq;
256 struct work_struct tx_work;
257 struct work_struct restart_work;
258
259 int force_quit;
260 int after_suspend;
261#define AFTER_SUSPEND_UP 1
262#define AFTER_SUSPEND_DOWN 2
263#define AFTER_SUSPEND_POWER 4
264#define AFTER_SUSPEND_RESTART 8
265 int restart_tx;
266};
267
268#define MCP251X_IS(_model) \
269static inline int mcp251x_is_##_model(struct spi_device *spi) \
270{ \
271 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); \
272 return priv->model == CAN_MCP251X_MCP##_model; \
273}
274
275MCP251X_IS(2510);
276MCP251X_IS(2515);
277
278static void mcp251x_clean(struct net_device *net)
279{
280 struct mcp251x_priv *priv = netdev_priv(net);
281
282 if (priv->tx_skb || priv->tx_len)
283 net->stats.tx_errors++;
284 if (priv->tx_skb)
285 dev_kfree_skb(priv->tx_skb);
286 if (priv->tx_len)
287 can_free_echo_skb(priv->net, 0);
288 priv->tx_skb = NULL;
289 priv->tx_len = 0;
290}
291
292/*
293 * Note about handling of error return of mcp251x_spi_trans: accessing
294 * registers via SPI is not really different conceptually than using
295 * normal I/O assembler instructions, although it's much more
296 * complicated from a practical POV. So it's not advisable to always
297 * check the return value of this function. Imagine that every
298 * read{b,l}, write{b,l} and friends would be bracketed in "if ( < 0)
299 * error();", it would be a great mess (well there are some situation
300 * when exception handling C++ like could be useful after all). So we
301 * just check that transfers are OK at the beginning of our
302 * conversation with the chip and to avoid doing really nasty things
303 * (like injecting bogus packets in the network stack).
304 */
305static int mcp251x_spi_trans(struct spi_device *spi, int len)
306{
307 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
308 struct spi_transfer t = {
309 .tx_buf = priv->spi_tx_buf,
310 .rx_buf = priv->spi_rx_buf,
311 .len = len,
312 .cs_change = 0,
313 };
314 struct spi_message m;
315 int ret;
316
317 spi_message_init(&m);
318
319 if (mcp251x_enable_dma) {
320 t.tx_dma = priv->spi_tx_dma;
321 t.rx_dma = priv->spi_rx_dma;
322 m.is_dma_mapped = 1;
323 }
324
325 spi_message_add_tail(&t, &m);
326
327 ret = spi_sync(spi, &m);
328 if (ret)
329 dev_err(&spi->dev, "spi transfer failed: ret = %d\n", ret);
330 return ret;
331}
332
333static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
334{
335 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
336 u8 val = 0;
337
338 priv->spi_tx_buf[0] = INSTRUCTION_READ;
339 priv->spi_tx_buf[1] = reg;
340
341 mcp251x_spi_trans(spi, 3);
342 val = priv->spi_rx_buf[2];
343
344 return val;
345}
346
347static void mcp251x_read_2regs(struct spi_device *spi, uint8_t reg,
348 uint8_t *v1, uint8_t *v2)
349{
350 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
351
352 priv->spi_tx_buf[0] = INSTRUCTION_READ;
353 priv->spi_tx_buf[1] = reg;
354
355 mcp251x_spi_trans(spi, 4);
356
357 *v1 = priv->spi_rx_buf[2];
358 *v2 = priv->spi_rx_buf[3];
359}
360
361static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val)
362{
363 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
364
365 priv->spi_tx_buf[0] = INSTRUCTION_WRITE;
366 priv->spi_tx_buf[1] = reg;
367 priv->spi_tx_buf[2] = val;
368
369 mcp251x_spi_trans(spi, 3);
370}
371
372static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
373 u8 mask, uint8_t val)
374{
375 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
376
377 priv->spi_tx_buf[0] = INSTRUCTION_BIT_MODIFY;
378 priv->spi_tx_buf[1] = reg;
379 priv->spi_tx_buf[2] = mask;
380 priv->spi_tx_buf[3] = val;
381
382 mcp251x_spi_trans(spi, 4);
383}
384
385static void mcp251x_hw_tx_frame(struct spi_device *spi, u8 *buf,
386 int len, int tx_buf_idx)
387{
388 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
389
390 if (mcp251x_is_2510(spi)) {
391 int i;
392
393 for (i = 1; i < TXBDAT_OFF + len; i++)
394 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + i,
395 buf[i]);
396 } else {
397 memcpy(priv->spi_tx_buf, buf, TXBDAT_OFF + len);
398 mcp251x_spi_trans(spi, TXBDAT_OFF + len);
399 }
400}
401
402static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame,
403 int tx_buf_idx)
404{
405 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
406 u32 sid, eid, exide, rtr;
407 u8 buf[SPI_TRANSFER_BUF_LEN];
408
409 exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */
410 if (exide)
411 sid = (frame->can_id & CAN_EFF_MASK) >> 18;
412 else
413 sid = frame->can_id & CAN_SFF_MASK; /* Standard ID */
414 eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */
415 rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */
416
417 buf[TXBCTRL_OFF] = INSTRUCTION_LOAD_TXB(tx_buf_idx);
418 buf[TXBSIDH_OFF] = sid >> SIDH_SHIFT;
419 buf[TXBSIDL_OFF] = ((sid & SIDL_SID_MASK) << SIDL_SID_SHIFT) |
420 (exide << SIDL_EXIDE_SHIFT) |
421 ((eid >> SIDL_EID_SHIFT) & SIDL_EID_MASK);
422 buf[TXBEID8_OFF] = GET_BYTE(eid, 1);
423 buf[TXBEID0_OFF] = GET_BYTE(eid, 0);
424 buf[TXBDLC_OFF] = (rtr << DLC_RTR_SHIFT) | frame->can_dlc;
425 memcpy(buf + TXBDAT_OFF, frame->data, frame->can_dlc);
426 mcp251x_hw_tx_frame(spi, buf, frame->can_dlc, tx_buf_idx);
427
428 /* use INSTRUCTION_RTS, to avoid "repeated frame problem" */
429 priv->spi_tx_buf[0] = INSTRUCTION_RTS(1 << tx_buf_idx);
430 mcp251x_spi_trans(priv->spi, 1);
431}
432
433static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
434 int buf_idx)
435{
436 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
437
438 if (mcp251x_is_2510(spi)) {
439 int i, len;
440
441 for (i = 1; i < RXBDAT_OFF; i++)
442 buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
443
444 len = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
445 for (; i < (RXBDAT_OFF + len); i++)
446 buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
447 } else {
448 priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);
449 mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);
450 memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);
451 }
452}
453
454static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
455{
456 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
457 struct sk_buff *skb;
458 struct can_frame *frame;
459 u8 buf[SPI_TRANSFER_BUF_LEN];
460
461 skb = alloc_can_skb(priv->net, &frame);
462 if (!skb) {
463 dev_err(&spi->dev, "cannot allocate RX skb\n");
464 priv->net->stats.rx_dropped++;
465 return;
466 }
467
468 mcp251x_hw_rx_frame(spi, buf, buf_idx);
469 if (buf[RXBSIDL_OFF] & RXBSIDL_IDE) {
470 /* Extended ID format */
471 frame->can_id = CAN_EFF_FLAG;
472 frame->can_id |=
473 /* Extended ID part */
474 SET_BYTE(buf[RXBSIDL_OFF] & RXBSIDL_EID, 2) |
475 SET_BYTE(buf[RXBEID8_OFF], 1) |
476 SET_BYTE(buf[RXBEID0_OFF], 0) |
477 /* Standard ID part */
478 (((buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |
479 (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT)) << 18);
480 /* Remote transmission request */
481 if (buf[RXBDLC_OFF] & RXBDLC_RTR)
482 frame->can_id |= CAN_RTR_FLAG;
483 } else {
484 /* Standard ID format */
485 frame->can_id =
486 (buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |
487 (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT);
488 if (buf[RXBSIDL_OFF] & RXBSIDL_SRR)
489 frame->can_id |= CAN_RTR_FLAG;
490 }
491 /* Data length */
492 frame->can_dlc = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
493 memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc);
494
495 priv->net->stats.rx_packets++;
496 priv->net->stats.rx_bytes += frame->can_dlc;
497 netif_rx_ni(skb);
498}
499
500static void mcp251x_hw_sleep(struct spi_device *spi)
501{
502 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_SLEEP);
503}
504
505static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,
506 struct net_device *net)
507{
508 struct mcp251x_priv *priv = netdev_priv(net);
509 struct spi_device *spi = priv->spi;
510
511 if (priv->tx_skb || priv->tx_len) {
512 dev_warn(&spi->dev, "hard_xmit called while tx busy\n");
513 return NETDEV_TX_BUSY;
514 }
515
516 if (can_dropped_invalid_skb(net, skb))
517 return NETDEV_TX_OK;
518
519 netif_stop_queue(net);
520 priv->tx_skb = skb;
521 queue_work(priv->wq, &priv->tx_work);
522
523 return NETDEV_TX_OK;
524}
525
526static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode)
527{
528 struct mcp251x_priv *priv = netdev_priv(net);
529
530 switch (mode) {
531 case CAN_MODE_START:
532 mcp251x_clean(net);
533 /* We have to delay work since SPI I/O may sleep */
534 priv->can.state = CAN_STATE_ERROR_ACTIVE;
535 priv->restart_tx = 1;
536 if (priv->can.restart_ms == 0)
537 priv->after_suspend = AFTER_SUSPEND_RESTART;
538 queue_work(priv->wq, &priv->restart_work);
539 break;
540 default:
541 return -EOPNOTSUPP;
542 }
543
544 return 0;
545}
546
547static int mcp251x_set_normal_mode(struct spi_device *spi)
548{
549 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
550 unsigned long timeout;
551
552 /* Enable interrupts */
553 mcp251x_write_reg(spi, CANINTE,
554 CANINTE_ERRIE | CANINTE_TX2IE | CANINTE_TX1IE |
555 CANINTE_TX0IE | CANINTE_RX1IE | CANINTE_RX0IE);
556
557 if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
558 /* Put device into loopback mode */
559 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LOOPBACK);
560 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
561 /* Put device into listen-only mode */
562 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LISTEN_ONLY);
563 } else {
564 /* Put device into normal mode */
565 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);
566
567 /* Wait for the device to enter normal mode */
568 timeout = jiffies + HZ;
569 while (mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) {
570 schedule();
571 if (time_after(jiffies, timeout)) {
572 dev_err(&spi->dev, "MCP251x didn't"
573 " enter in normal mode\n");
574 return -EBUSY;
575 }
576 }
577 }
578 priv->can.state = CAN_STATE_ERROR_ACTIVE;
579 return 0;
580}
581
582static int mcp251x_do_set_bittiming(struct net_device *net)
583{
584 struct mcp251x_priv *priv = netdev_priv(net);
585 struct can_bittiming *bt = &priv->can.bittiming;
586 struct spi_device *spi = priv->spi;
587
588 mcp251x_write_reg(spi, CNF1, ((bt->sjw - 1) << CNF1_SJW_SHIFT) |
589 (bt->brp - 1));
590 mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE |
591 (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES ?
592 CNF2_SAM : 0) |
593 ((bt->phase_seg1 - 1) << CNF2_PS1_SHIFT) |
594 (bt->prop_seg - 1));
595 mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK,
596 (bt->phase_seg2 - 1));
597 dev_info(&spi->dev, "CNF: 0x%02x 0x%02x 0x%02x\n",
598 mcp251x_read_reg(spi, CNF1),
599 mcp251x_read_reg(spi, CNF2),
600 mcp251x_read_reg(spi, CNF3));
601
602 return 0;
603}
604
605static int mcp251x_setup(struct net_device *net, struct mcp251x_priv *priv,
606 struct spi_device *spi)
607{
608 mcp251x_do_set_bittiming(net);
609
610 mcp251x_write_reg(spi, RXBCTRL(0),
611 RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1);
612 mcp251x_write_reg(spi, RXBCTRL(1),
613 RXBCTRL_RXM0 | RXBCTRL_RXM1);
614 return 0;
615}
616
617static int mcp251x_hw_reset(struct spi_device *spi)
618{
619 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
620 int ret;
621 unsigned long timeout;
622
623 priv->spi_tx_buf[0] = INSTRUCTION_RESET;
624 ret = spi_write(spi, priv->spi_tx_buf, 1);
625 if (ret) {
626 dev_err(&spi->dev, "reset failed: ret = %d\n", ret);
627 return -EIO;
628 }
629
630 /* Wait for reset to finish */
631 timeout = jiffies + HZ;
632 mdelay(10);
633 while ((mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK)
634 != CANCTRL_REQOP_CONF) {
635 schedule();
636 if (time_after(jiffies, timeout)) {
637 dev_err(&spi->dev, "MCP251x didn't"
638 " enter in conf mode after reset\n");
639 return -EBUSY;
640 }
641 }
642 return 0;
643}
644
645static int mcp251x_hw_probe(struct spi_device *spi)
646{
647 int st1, st2;
648
649 mcp251x_hw_reset(spi);
650
651 /*
652 * Please note that these are "magic values" based on after
653 * reset defaults taken from data sheet which allows us to see
654 * if we really have a chip on the bus (we avoid common all
655 * zeroes or all ones situations)
656 */
657 st1 = mcp251x_read_reg(spi, CANSTAT) & 0xEE;
658 st2 = mcp251x_read_reg(spi, CANCTRL) & 0x17;
659
660 dev_dbg(&spi->dev, "CANSTAT 0x%02x CANCTRL 0x%02x\n", st1, st2);
661
662 /* Check for power up default values */
663 return (st1 == 0x80 && st2 == 0x07) ? 1 : 0;
664}
665
666static void mcp251x_open_clean(struct net_device *net)
667{
668 struct mcp251x_priv *priv = netdev_priv(net);
669 struct spi_device *spi = priv->spi;
670 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
671
672 free_irq(spi->irq, priv);
673 mcp251x_hw_sleep(spi);
674 if (pdata->transceiver_enable)
675 pdata->transceiver_enable(0);
676 close_candev(net);
677}
678
679static int mcp251x_stop(struct net_device *net)
680{
681 struct mcp251x_priv *priv = netdev_priv(net);
682 struct spi_device *spi = priv->spi;
683 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
684
685 close_candev(net);
686
687 priv->force_quit = 1;
688 free_irq(spi->irq, priv);
689 destroy_workqueue(priv->wq);
690 priv->wq = NULL;
691
692 mutex_lock(&priv->mcp_lock);
693
694 /* Disable and clear pending interrupts */
695 mcp251x_write_reg(spi, CANINTE, 0x00);
696 mcp251x_write_reg(spi, CANINTF, 0x00);
697
698 mcp251x_write_reg(spi, TXBCTRL(0), 0);
699 mcp251x_clean(net);
700
701 mcp251x_hw_sleep(spi);
702
703 if (pdata->transceiver_enable)
704 pdata->transceiver_enable(0);
705
706 priv->can.state = CAN_STATE_STOPPED;
707
708 mutex_unlock(&priv->mcp_lock);
709
710 return 0;
711}
712
713static void mcp251x_error_skb(struct net_device *net, int can_id, int data1)
714{
715 struct sk_buff *skb;
716 struct can_frame *frame;
717
718 skb = alloc_can_err_skb(net, &frame);
719 if (skb) {
720 frame->can_id |= can_id;
721 frame->data[1] = data1;
722 netif_rx_ni(skb);
723 } else {
724 netdev_err(net, "cannot allocate error skb\n");
725 }
726}
727
728static void mcp251x_tx_work_handler(struct work_struct *ws)
729{
730 struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
731 tx_work);
732 struct spi_device *spi = priv->spi;
733 struct net_device *net = priv->net;
734 struct can_frame *frame;
735
736 mutex_lock(&priv->mcp_lock);
737 if (priv->tx_skb) {
738 if (priv->can.state == CAN_STATE_BUS_OFF) {
739 mcp251x_clean(net);
740 } else {
741 frame = (struct can_frame *)priv->tx_skb->data;
742
743 if (frame->can_dlc > CAN_FRAME_MAX_DATA_LEN)
744 frame->can_dlc = CAN_FRAME_MAX_DATA_LEN;
745 mcp251x_hw_tx(spi, frame, 0);
746 priv->tx_len = 1 + frame->can_dlc;
747 can_put_echo_skb(priv->tx_skb, net, 0);
748 priv->tx_skb = NULL;
749 }
750 }
751 mutex_unlock(&priv->mcp_lock);
752}
753
754static void mcp251x_restart_work_handler(struct work_struct *ws)
755{
756 struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
757 restart_work);
758 struct spi_device *spi = priv->spi;
759 struct net_device *net = priv->net;
760
761 mutex_lock(&priv->mcp_lock);
762 if (priv->after_suspend) {
763 mdelay(10);
764 mcp251x_hw_reset(spi);
765 mcp251x_setup(net, priv, spi);
766 if (priv->after_suspend & AFTER_SUSPEND_RESTART) {
767 mcp251x_set_normal_mode(spi);
768 } else if (priv->after_suspend & AFTER_SUSPEND_UP) {
769 netif_device_attach(net);
770 mcp251x_clean(net);
771 mcp251x_set_normal_mode(spi);
772 netif_wake_queue(net);
773 } else {
774 mcp251x_hw_sleep(spi);
775 }
776 priv->after_suspend = 0;
777 priv->force_quit = 0;
778 }
779
780 if (priv->restart_tx) {
781 priv->restart_tx = 0;
782 mcp251x_write_reg(spi, TXBCTRL(0), 0);
783 mcp251x_clean(net);
784 netif_wake_queue(net);
785 mcp251x_error_skb(net, CAN_ERR_RESTARTED, 0);
786 }
787 mutex_unlock(&priv->mcp_lock);
788}
789
790static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
791{
792 struct mcp251x_priv *priv = dev_id;
793 struct spi_device *spi = priv->spi;
794 struct net_device *net = priv->net;
795
796 mutex_lock(&priv->mcp_lock);
797 while (!priv->force_quit) {
798 enum can_state new_state;
799 u8 intf, eflag;
800 u8 clear_intf = 0;
801 int can_id = 0, data1 = 0;
802
803 mcp251x_read_2regs(spi, CANINTF, &intf, &eflag);
804
805 /* mask out flags we don't care about */
806 intf &= CANINTF_RX | CANINTF_TX | CANINTF_ERR;
807
808 /* receive buffer 0 */
809 if (intf & CANINTF_RX0IF) {
810 mcp251x_hw_rx(spi, 0);
811 /*
812 * Free one buffer ASAP
813 * (The MCP2515 does this automatically.)
814 */
815 if (mcp251x_is_2510(spi))
816 mcp251x_write_bits(spi, CANINTF, CANINTF_RX0IF, 0x00);
817 }
818
819 /* receive buffer 1 */
820 if (intf & CANINTF_RX1IF) {
821 mcp251x_hw_rx(spi, 1);
822 /* the MCP2515 does this automatically */
823 if (mcp251x_is_2510(spi))
824 clear_intf |= CANINTF_RX1IF;
825 }
826
827 /* any error or tx interrupt we need to clear? */
828 if (intf & (CANINTF_ERR | CANINTF_TX))
829 clear_intf |= intf & (CANINTF_ERR | CANINTF_TX);
830 if (clear_intf)
831 mcp251x_write_bits(spi, CANINTF, clear_intf, 0x00);
832
833 if (eflag)
834 mcp251x_write_bits(spi, EFLG, eflag, 0x00);
835
836 /* Update can state */
837 if (eflag & EFLG_TXBO) {
838 new_state = CAN_STATE_BUS_OFF;
839 can_id |= CAN_ERR_BUSOFF;
840 } else if (eflag & EFLG_TXEP) {
841 new_state = CAN_STATE_ERROR_PASSIVE;
842 can_id |= CAN_ERR_CRTL;
843 data1 |= CAN_ERR_CRTL_TX_PASSIVE;
844 } else if (eflag & EFLG_RXEP) {
845 new_state = CAN_STATE_ERROR_PASSIVE;
846 can_id |= CAN_ERR_CRTL;
847 data1 |= CAN_ERR_CRTL_RX_PASSIVE;
848 } else if (eflag & EFLG_TXWAR) {
849 new_state = CAN_STATE_ERROR_WARNING;
850 can_id |= CAN_ERR_CRTL;
851 data1 |= CAN_ERR_CRTL_TX_WARNING;
852 } else if (eflag & EFLG_RXWAR) {
853 new_state = CAN_STATE_ERROR_WARNING;
854 can_id |= CAN_ERR_CRTL;
855 data1 |= CAN_ERR_CRTL_RX_WARNING;
856 } else {
857 new_state = CAN_STATE_ERROR_ACTIVE;
858 }
859
860 /* Update can state statistics */
861 switch (priv->can.state) {
862 case CAN_STATE_ERROR_ACTIVE:
863 if (new_state >= CAN_STATE_ERROR_WARNING &&
864 new_state <= CAN_STATE_BUS_OFF)
865 priv->can.can_stats.error_warning++;
866 case CAN_STATE_ERROR_WARNING: /* fallthrough */
867 if (new_state >= CAN_STATE_ERROR_PASSIVE &&
868 new_state <= CAN_STATE_BUS_OFF)
869 priv->can.can_stats.error_passive++;
870 break;
871 default:
872 break;
873 }
874 priv->can.state = new_state;
875
876 if (intf & CANINTF_ERRIF) {
877 /* Handle overflow counters */
878 if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) {
879 if (eflag & EFLG_RX0OVR) {
880 net->stats.rx_over_errors++;
881 net->stats.rx_errors++;
882 }
883 if (eflag & EFLG_RX1OVR) {
884 net->stats.rx_over_errors++;
885 net->stats.rx_errors++;
886 }
887 can_id |= CAN_ERR_CRTL;
888 data1 |= CAN_ERR_CRTL_RX_OVERFLOW;
889 }
890 mcp251x_error_skb(net, can_id, data1);
891 }
892
893 if (priv->can.state == CAN_STATE_BUS_OFF) {
894 if (priv->can.restart_ms == 0) {
895 priv->force_quit = 1;
896 can_bus_off(net);
897 mcp251x_hw_sleep(spi);
898 break;
899 }
900 }
901
902 if (intf == 0)
903 break;
904
905 if (intf & CANINTF_TX) {
906 net->stats.tx_packets++;
907 net->stats.tx_bytes += priv->tx_len - 1;
908 if (priv->tx_len) {
909 can_get_echo_skb(net, 0);
910 priv->tx_len = 0;
911 }
912 netif_wake_queue(net);
913 }
914
915 }
916 mutex_unlock(&priv->mcp_lock);
917 return IRQ_HANDLED;
918}
919
920static int mcp251x_open(struct net_device *net)
921{
922 struct mcp251x_priv *priv = netdev_priv(net);
923 struct spi_device *spi = priv->spi;
924 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
925 int ret;
926
927 ret = open_candev(net);
928 if (ret) {
929 dev_err(&spi->dev, "unable to set initial baudrate!\n");
930 return ret;
931 }
932
933 mutex_lock(&priv->mcp_lock);
934 if (pdata->transceiver_enable)
935 pdata->transceiver_enable(1);
936
937 priv->force_quit = 0;
938 priv->tx_skb = NULL;
939 priv->tx_len = 0;
940
941 ret = request_threaded_irq(spi->irq, NULL, mcp251x_can_ist,
942 pdata->irq_flags ? pdata->irq_flags : IRQF_TRIGGER_FALLING,
943 DEVICE_NAME, priv);
944 if (ret) {
945 dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
946 if (pdata->transceiver_enable)
947 pdata->transceiver_enable(0);
948 close_candev(net);
949 goto open_unlock;
950 }
951
952 priv->wq = create_freezable_workqueue("mcp251x_wq");
953 INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
954 INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
955
956 ret = mcp251x_hw_reset(spi);
957 if (ret) {
958 mcp251x_open_clean(net);
959 goto open_unlock;
960 }
961 ret = mcp251x_setup(net, priv, spi);
962 if (ret) {
963 mcp251x_open_clean(net);
964 goto open_unlock;
965 }
966 ret = mcp251x_set_normal_mode(spi);
967 if (ret) {
968 mcp251x_open_clean(net);
969 goto open_unlock;
970 }
971 netif_wake_queue(net);
972
973open_unlock:
974 mutex_unlock(&priv->mcp_lock);
975 return ret;
976}
977
978static const struct net_device_ops mcp251x_netdev_ops = {
979 .ndo_open = mcp251x_open,
980 .ndo_stop = mcp251x_stop,
981 .ndo_start_xmit = mcp251x_hard_start_xmit,
982};
983
984static int __devinit mcp251x_can_probe(struct spi_device *spi)
985{
986 struct net_device *net;
987 struct mcp251x_priv *priv;
988 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
989 int ret = -ENODEV;
990
991 if (!pdata)
992 /* Platform data is required for osc freq */
993 goto error_out;
994
995 /* Allocate can/net device */
996 net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX);
997 if (!net) {
998 ret = -ENOMEM;
999 goto error_alloc;
1000 }
1001
1002 net->netdev_ops = &mcp251x_netdev_ops;
1003 net->flags |= IFF_ECHO;
1004
1005 priv = netdev_priv(net);
1006 priv->can.bittiming_const = &mcp251x_bittiming_const;
1007 priv->can.do_set_mode = mcp251x_do_set_mode;
1008 priv->can.clock.freq = pdata->oscillator_frequency / 2;
1009 priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
1010 CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY;
1011 priv->model = spi_get_device_id(spi)->driver_data;
1012 priv->net = net;
1013 dev_set_drvdata(&spi->dev, priv);
1014
1015 priv->spi = spi;
1016 mutex_init(&priv->mcp_lock);
1017
1018 /* If requested, allocate DMA buffers */
1019 if (mcp251x_enable_dma) {
1020 spi->dev.coherent_dma_mask = ~0;
1021
1022 /*
1023 * Minimum coherent DMA allocation is PAGE_SIZE, so allocate
1024 * that much and share it between Tx and Rx DMA buffers.
1025 */
1026 priv->spi_tx_buf = dma_alloc_coherent(&spi->dev,
1027 PAGE_SIZE,
1028 &priv->spi_tx_dma,
1029 GFP_DMA);
1030
1031 if (priv->spi_tx_buf) {
1032 priv->spi_rx_buf = (u8 *)(priv->spi_tx_buf +
1033 (PAGE_SIZE / 2));
1034 priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
1035 (PAGE_SIZE / 2));
1036 } else {
1037 /* Fall back to non-DMA */
1038 mcp251x_enable_dma = 0;
1039 }
1040 }
1041
1042 /* Allocate non-DMA buffers */
1043 if (!mcp251x_enable_dma) {
1044 priv->spi_tx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
1045 if (!priv->spi_tx_buf) {
1046 ret = -ENOMEM;
1047 goto error_tx_buf;
1048 }
1049 priv->spi_rx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
1050 if (!priv->spi_rx_buf) {
1051 ret = -ENOMEM;
1052 goto error_rx_buf;
1053 }
1054 }
1055
1056 if (pdata->power_enable)
1057 pdata->power_enable(1);
1058
1059 /* Call out to platform specific setup */
1060 if (pdata->board_specific_setup)
1061 pdata->board_specific_setup(spi);
1062
1063 SET_NETDEV_DEV(net, &spi->dev);
1064
1065 /* Configure the SPI bus */
1066 spi->mode = SPI_MODE_0;
1067 spi->bits_per_word = 8;
1068 spi_setup(spi);
1069
1070 /* Here is OK to not lock the MCP, no one knows about it yet */
1071 if (!mcp251x_hw_probe(spi)) {
1072 dev_info(&spi->dev, "Probe failed\n");
1073 goto error_probe;
1074 }
1075 mcp251x_hw_sleep(spi);
1076
1077 if (pdata->transceiver_enable)
1078 pdata->transceiver_enable(0);
1079
1080 ret = register_candev(net);
1081 if (!ret) {
1082 dev_info(&spi->dev, "probed\n");
1083 return ret;
1084 }
1085error_probe:
1086 if (!mcp251x_enable_dma)
1087 kfree(priv->spi_rx_buf);
1088error_rx_buf:
1089 if (!mcp251x_enable_dma)
1090 kfree(priv->spi_tx_buf);
1091error_tx_buf:
1092 free_candev(net);
1093 if (mcp251x_enable_dma)
1094 dma_free_coherent(&spi->dev, PAGE_SIZE,
1095 priv->spi_tx_buf, priv->spi_tx_dma);
1096error_alloc:
1097 if (pdata->power_enable)
1098 pdata->power_enable(0);
1099 dev_err(&spi->dev, "probe failed\n");
1100error_out:
1101 return ret;
1102}
1103
1104static int __devexit mcp251x_can_remove(struct spi_device *spi)
1105{
1106 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1107 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
1108 struct net_device *net = priv->net;
1109
1110 unregister_candev(net);
1111 free_candev(net);
1112
1113 if (mcp251x_enable_dma) {
1114 dma_free_coherent(&spi->dev, PAGE_SIZE,
1115 priv->spi_tx_buf, priv->spi_tx_dma);
1116 } else {
1117 kfree(priv->spi_tx_buf);
1118 kfree(priv->spi_rx_buf);
1119 }
1120
1121 if (pdata->power_enable)
1122 pdata->power_enable(0);
1123
1124 return 0;
1125}
1126
1127#ifdef CONFIG_PM
1128static int mcp251x_can_suspend(struct spi_device *spi, pm_message_t state)
1129{
1130 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1131 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
1132 struct net_device *net = priv->net;
1133
1134 priv->force_quit = 1;
1135 disable_irq(spi->irq);
1136 /*
1137 * Note: at this point neither IST nor workqueues are running.
1138 * open/stop cannot be called anyway so locking is not needed
1139 */
1140 if (netif_running(net)) {
1141 netif_device_detach(net);
1142
1143 mcp251x_hw_sleep(spi);
1144 if (pdata->transceiver_enable)
1145 pdata->transceiver_enable(0);
1146 priv->after_suspend = AFTER_SUSPEND_UP;
1147 } else {
1148 priv->after_suspend = AFTER_SUSPEND_DOWN;
1149 }
1150
1151 if (pdata->power_enable) {
1152 pdata->power_enable(0);
1153 priv->after_suspend |= AFTER_SUSPEND_POWER;
1154 }
1155
1156 return 0;
1157}
1158
1159static int mcp251x_can_resume(struct spi_device *spi)
1160{
1161 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1162 struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
1163
1164 if (priv->after_suspend & AFTER_SUSPEND_POWER) {
1165 pdata->power_enable(1);
1166 queue_work(priv->wq, &priv->restart_work);
1167 } else {
1168 if (priv->after_suspend & AFTER_SUSPEND_UP) {
1169 if (pdata->transceiver_enable)
1170 pdata->transceiver_enable(1);
1171 queue_work(priv->wq, &priv->restart_work);
1172 } else {
1173 priv->after_suspend = 0;
1174 }
1175 }
1176 priv->force_quit = 0;
1177 enable_irq(spi->irq);
1178 return 0;
1179}
1180#else
1181#define mcp251x_can_suspend NULL
1182#define mcp251x_can_resume NULL
1183#endif
1184
1185static const struct spi_device_id mcp251x_id_table[] = {
1186 { "mcp2510", CAN_MCP251X_MCP2510 },
1187 { "mcp2515", CAN_MCP251X_MCP2515 },
1188 { },
1189};
1190
1191MODULE_DEVICE_TABLE(spi, mcp251x_id_table);
1192
1193static struct spi_driver mcp251x_can_driver = {
1194 .driver = {
1195 .name = DEVICE_NAME,
1196 .bus = &spi_bus_type,
1197 .owner = THIS_MODULE,
1198 },
1199
1200 .id_table = mcp251x_id_table,
1201 .probe = mcp251x_can_probe,
1202 .remove = __devexit_p(mcp251x_can_remove),
1203 .suspend = mcp251x_can_suspend,
1204 .resume = mcp251x_can_resume,
1205};
1206
1207static int __init mcp251x_can_init(void)
1208{
1209 return spi_register_driver(&mcp251x_can_driver);
1210}
1211
1212static void __exit mcp251x_can_exit(void)
1213{
1214 spi_unregister_driver(&mcp251x_can_driver);
1215}
1216
1217module_init(mcp251x_can_init);
1218module_exit(mcp251x_can_exit);
1219
1220MODULE_AUTHOR("Chris Elston <celston@katalix.com>, "
1221 "Christian Pellegrin <chripell@evolware.org>");
1222MODULE_DESCRIPTION("Microchip 251x CAN driver");
1223MODULE_LICENSE("GPL v2");