ARM: mm: Recreate kernel mappings in early_paging_init()
[linux/fpc-iii.git] / drivers / net / can / mcp251x.c
blobfe7dd696957ea3d8c4f7e34b21baa866bb797b55
1 /*
2 * CAN bus driver for Microchip 251x CAN Controller with SPI Interface
4 * MCP2510 support and bug fixes by Christian Pellegrin
5 * <chripell@evolware.org>
7 * Copyright 2009 Christian Pellegrin EVOL S.r.l.
9 * Copyright 2007 Raymarine UK, Ltd. All Rights Reserved.
10 * Written under contract by:
11 * Chris Elston, Katalix Systems, Ltd.
13 * Based on Microchip MCP251x CAN controller driver written by
14 * David Vrabel, Copyright 2006 Arcom Control Systems Ltd.
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
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
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.
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
36 * Your platform definition file should specify something like:
38 * static struct mcp251x_platform_data mcp251x_info = {
39 * .oscillator_frequency = 8000000,
40 * };
42 * static struct spi_board_info spi_board_info[] = {
43 * {
44 * .modalias = "mcp2510",
45 * // or "mcp2515" depending on your controller
46 * .platform_data = &mcp251x_info,
47 * .irq = IRQ_EINT13,
48 * .max_speed_hz = 2*1000*1000,
49 * .chip_select = 2,
50 * },
51 * };
53 * Please see mcp251x.h for a description of the fields in
54 * struct mcp251x_platform_data.
58 #include <linux/can/core.h>
59 #include <linux/can/dev.h>
60 #include <linux/can/led.h>
61 #include <linux/can/platform/mcp251x.h>
62 #include <linux/completion.h>
63 #include <linux/delay.h>
64 #include <linux/device.h>
65 #include <linux/dma-mapping.h>
66 #include <linux/freezer.h>
67 #include <linux/interrupt.h>
68 #include <linux/io.h>
69 #include <linux/kernel.h>
70 #include <linux/module.h>
71 #include <linux/netdevice.h>
72 #include <linux/platform_device.h>
73 #include <linux/slab.h>
74 #include <linux/spi/spi.h>
75 #include <linux/uaccess.h>
76 #include <linux/regulator/consumer.h>
78 /* SPI interface instruction set */
79 #define INSTRUCTION_WRITE 0x02
80 #define INSTRUCTION_READ 0x03
81 #define INSTRUCTION_BIT_MODIFY 0x05
82 #define INSTRUCTION_LOAD_TXB(n) (0x40 + 2 * (n))
83 #define INSTRUCTION_READ_RXB(n) (((n) == 0) ? 0x90 : 0x94)
84 #define INSTRUCTION_RESET 0xC0
85 #define RTS_TXB0 0x01
86 #define RTS_TXB1 0x02
87 #define RTS_TXB2 0x04
88 #define INSTRUCTION_RTS(n) (0x80 | ((n) & 0x07))
91 /* MPC251x registers */
92 #define CANSTAT 0x0e
93 #define CANCTRL 0x0f
94 # define CANCTRL_REQOP_MASK 0xe0
95 # define CANCTRL_REQOP_CONF 0x80
96 # define CANCTRL_REQOP_LISTEN_ONLY 0x60
97 # define CANCTRL_REQOP_LOOPBACK 0x40
98 # define CANCTRL_REQOP_SLEEP 0x20
99 # define CANCTRL_REQOP_NORMAL 0x00
100 # define CANCTRL_OSM 0x08
101 # define CANCTRL_ABAT 0x10
102 #define TEC 0x1c
103 #define REC 0x1d
104 #define CNF1 0x2a
105 # define CNF1_SJW_SHIFT 6
106 #define CNF2 0x29
107 # define CNF2_BTLMODE 0x80
108 # define CNF2_SAM 0x40
109 # define CNF2_PS1_SHIFT 3
110 #define CNF3 0x28
111 # define CNF3_SOF 0x08
112 # define CNF3_WAKFIL 0x04
113 # define CNF3_PHSEG2_MASK 0x07
114 #define CANINTE 0x2b
115 # define CANINTE_MERRE 0x80
116 # define CANINTE_WAKIE 0x40
117 # define CANINTE_ERRIE 0x20
118 # define CANINTE_TX2IE 0x10
119 # define CANINTE_TX1IE 0x08
120 # define CANINTE_TX0IE 0x04
121 # define CANINTE_RX1IE 0x02
122 # define CANINTE_RX0IE 0x01
123 #define CANINTF 0x2c
124 # define CANINTF_MERRF 0x80
125 # define CANINTF_WAKIF 0x40
126 # define CANINTF_ERRIF 0x20
127 # define CANINTF_TX2IF 0x10
128 # define CANINTF_TX1IF 0x08
129 # define CANINTF_TX0IF 0x04
130 # define CANINTF_RX1IF 0x02
131 # define CANINTF_RX0IF 0x01
132 # define CANINTF_RX (CANINTF_RX0IF | CANINTF_RX1IF)
133 # define CANINTF_TX (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)
134 # define CANINTF_ERR (CANINTF_ERRIF)
135 #define EFLG 0x2d
136 # define EFLG_EWARN 0x01
137 # define EFLG_RXWAR 0x02
138 # define EFLG_TXWAR 0x04
139 # define EFLG_RXEP 0x08
140 # define EFLG_TXEP 0x10
141 # define EFLG_TXBO 0x20
142 # define EFLG_RX0OVR 0x40
143 # define EFLG_RX1OVR 0x80
144 #define TXBCTRL(n) (((n) * 0x10) + 0x30 + TXBCTRL_OFF)
145 # define TXBCTRL_ABTF 0x40
146 # define TXBCTRL_MLOA 0x20
147 # define TXBCTRL_TXERR 0x10
148 # define TXBCTRL_TXREQ 0x08
149 #define TXBSIDH(n) (((n) * 0x10) + 0x30 + TXBSIDH_OFF)
150 # define SIDH_SHIFT 3
151 #define TXBSIDL(n) (((n) * 0x10) + 0x30 + TXBSIDL_OFF)
152 # define SIDL_SID_MASK 7
153 # define SIDL_SID_SHIFT 5
154 # define SIDL_EXIDE_SHIFT 3
155 # define SIDL_EID_SHIFT 16
156 # define SIDL_EID_MASK 3
157 #define TXBEID8(n) (((n) * 0x10) + 0x30 + TXBEID8_OFF)
158 #define TXBEID0(n) (((n) * 0x10) + 0x30 + TXBEID0_OFF)
159 #define TXBDLC(n) (((n) * 0x10) + 0x30 + TXBDLC_OFF)
160 # define DLC_RTR_SHIFT 6
161 #define TXBCTRL_OFF 0
162 #define TXBSIDH_OFF 1
163 #define TXBSIDL_OFF 2
164 #define TXBEID8_OFF 3
165 #define TXBEID0_OFF 4
166 #define TXBDLC_OFF 5
167 #define TXBDAT_OFF 6
168 #define RXBCTRL(n) (((n) * 0x10) + 0x60 + RXBCTRL_OFF)
169 # define RXBCTRL_BUKT 0x04
170 # define RXBCTRL_RXM0 0x20
171 # define RXBCTRL_RXM1 0x40
172 #define RXBSIDH(n) (((n) * 0x10) + 0x60 + RXBSIDH_OFF)
173 # define RXBSIDH_SHIFT 3
174 #define RXBSIDL(n) (((n) * 0x10) + 0x60 + RXBSIDL_OFF)
175 # define RXBSIDL_IDE 0x08
176 # define RXBSIDL_SRR 0x10
177 # define RXBSIDL_EID 3
178 # define RXBSIDL_SHIFT 5
179 #define RXBEID8(n) (((n) * 0x10) + 0x60 + RXBEID8_OFF)
180 #define RXBEID0(n) (((n) * 0x10) + 0x60 + RXBEID0_OFF)
181 #define RXBDLC(n) (((n) * 0x10) + 0x60 + RXBDLC_OFF)
182 # define RXBDLC_LEN_MASK 0x0f
183 # define RXBDLC_RTR 0x40
184 #define RXBCTRL_OFF 0
185 #define RXBSIDH_OFF 1
186 #define RXBSIDL_OFF 2
187 #define RXBEID8_OFF 3
188 #define RXBEID0_OFF 4
189 #define RXBDLC_OFF 5
190 #define RXBDAT_OFF 6
191 #define RXFSIDH(n) ((n) * 4)
192 #define RXFSIDL(n) ((n) * 4 + 1)
193 #define RXFEID8(n) ((n) * 4 + 2)
194 #define RXFEID0(n) ((n) * 4 + 3)
195 #define RXMSIDH(n) ((n) * 4 + 0x20)
196 #define RXMSIDL(n) ((n) * 4 + 0x21)
197 #define RXMEID8(n) ((n) * 4 + 0x22)
198 #define RXMEID0(n) ((n) * 4 + 0x23)
200 #define GET_BYTE(val, byte) \
201 (((val) >> ((byte) * 8)) & 0xff)
202 #define SET_BYTE(val, byte) \
203 (((val) & 0xff) << ((byte) * 8))
206 * Buffer size required for the largest SPI transfer (i.e., reading a
207 * frame)
209 #define CAN_FRAME_MAX_DATA_LEN 8
210 #define SPI_TRANSFER_BUF_LEN (6 + CAN_FRAME_MAX_DATA_LEN)
211 #define CAN_FRAME_MAX_BITS 128
213 #define TX_ECHO_SKB_MAX 1
215 #define DEVICE_NAME "mcp251x"
217 static int mcp251x_enable_dma; /* Enable SPI DMA. Default: 0 (Off) */
218 module_param(mcp251x_enable_dma, int, S_IRUGO);
219 MODULE_PARM_DESC(mcp251x_enable_dma, "Enable SPI DMA. Default: 0 (Off)");
221 static const struct can_bittiming_const mcp251x_bittiming_const = {
222 .name = DEVICE_NAME,
223 .tseg1_min = 3,
224 .tseg1_max = 16,
225 .tseg2_min = 2,
226 .tseg2_max = 8,
227 .sjw_max = 4,
228 .brp_min = 1,
229 .brp_max = 64,
230 .brp_inc = 1,
233 enum mcp251x_model {
234 CAN_MCP251X_MCP2510 = 0x2510,
235 CAN_MCP251X_MCP2515 = 0x2515,
238 struct mcp251x_priv {
239 struct can_priv can;
240 struct net_device *net;
241 struct spi_device *spi;
242 enum mcp251x_model model;
244 struct mutex mcp_lock; /* SPI device lock */
246 u8 *spi_tx_buf;
247 u8 *spi_rx_buf;
248 dma_addr_t spi_tx_dma;
249 dma_addr_t spi_rx_dma;
251 struct sk_buff *tx_skb;
252 int tx_len;
254 struct workqueue_struct *wq;
255 struct work_struct tx_work;
256 struct work_struct restart_work;
258 int force_quit;
259 int after_suspend;
260 #define AFTER_SUSPEND_UP 1
261 #define AFTER_SUSPEND_DOWN 2
262 #define AFTER_SUSPEND_POWER 4
263 #define AFTER_SUSPEND_RESTART 8
264 int restart_tx;
265 struct regulator *power;
266 struct regulator *transceiver;
269 #define MCP251X_IS(_model) \
270 static inline int mcp251x_is_##_model(struct spi_device *spi) \
272 struct mcp251x_priv *priv = spi_get_drvdata(spi); \
273 return priv->model == CAN_MCP251X_MCP##_model; \
276 MCP251X_IS(2510);
277 MCP251X_IS(2515);
279 static void mcp251x_clean(struct net_device *net)
281 struct mcp251x_priv *priv = netdev_priv(net);
283 if (priv->tx_skb || priv->tx_len)
284 net->stats.tx_errors++;
285 if (priv->tx_skb)
286 dev_kfree_skb(priv->tx_skb);
287 if (priv->tx_len)
288 can_free_echo_skb(priv->net, 0);
289 priv->tx_skb = NULL;
290 priv->tx_len = 0;
294 * Note about handling of error return of mcp251x_spi_trans: accessing
295 * registers via SPI is not really different conceptually than using
296 * normal I/O assembler instructions, although it's much more
297 * complicated from a practical POV. So it's not advisable to always
298 * check the return value of this function. Imagine that every
299 * read{b,l}, write{b,l} and friends would be bracketed in "if ( < 0)
300 * error();", it would be a great mess (well there are some situation
301 * when exception handling C++ like could be useful after all). So we
302 * just check that transfers are OK at the beginning of our
303 * conversation with the chip and to avoid doing really nasty things
304 * (like injecting bogus packets in the network stack).
306 static int mcp251x_spi_trans(struct spi_device *spi, int len)
308 struct mcp251x_priv *priv = spi_get_drvdata(spi);
309 struct spi_transfer t = {
310 .tx_buf = priv->spi_tx_buf,
311 .rx_buf = priv->spi_rx_buf,
312 .len = len,
313 .cs_change = 0,
315 struct spi_message m;
316 int ret;
318 spi_message_init(&m);
320 if (mcp251x_enable_dma) {
321 t.tx_dma = priv->spi_tx_dma;
322 t.rx_dma = priv->spi_rx_dma;
323 m.is_dma_mapped = 1;
326 spi_message_add_tail(&t, &m);
328 ret = spi_sync(spi, &m);
329 if (ret)
330 dev_err(&spi->dev, "spi transfer failed: ret = %d\n", ret);
331 return ret;
334 static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
336 struct mcp251x_priv *priv = spi_get_drvdata(spi);
337 u8 val = 0;
339 priv->spi_tx_buf[0] = INSTRUCTION_READ;
340 priv->spi_tx_buf[1] = reg;
342 mcp251x_spi_trans(spi, 3);
343 val = priv->spi_rx_buf[2];
345 return val;
348 static void mcp251x_read_2regs(struct spi_device *spi, uint8_t reg,
349 uint8_t *v1, uint8_t *v2)
351 struct mcp251x_priv *priv = spi_get_drvdata(spi);
353 priv->spi_tx_buf[0] = INSTRUCTION_READ;
354 priv->spi_tx_buf[1] = reg;
356 mcp251x_spi_trans(spi, 4);
358 *v1 = priv->spi_rx_buf[2];
359 *v2 = priv->spi_rx_buf[3];
362 static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val)
364 struct mcp251x_priv *priv = spi_get_drvdata(spi);
366 priv->spi_tx_buf[0] = INSTRUCTION_WRITE;
367 priv->spi_tx_buf[1] = reg;
368 priv->spi_tx_buf[2] = val;
370 mcp251x_spi_trans(spi, 3);
373 static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
374 u8 mask, uint8_t val)
376 struct mcp251x_priv *priv = spi_get_drvdata(spi);
378 priv->spi_tx_buf[0] = INSTRUCTION_BIT_MODIFY;
379 priv->spi_tx_buf[1] = reg;
380 priv->spi_tx_buf[2] = mask;
381 priv->spi_tx_buf[3] = val;
383 mcp251x_spi_trans(spi, 4);
386 static void mcp251x_hw_tx_frame(struct spi_device *spi, u8 *buf,
387 int len, int tx_buf_idx)
389 struct mcp251x_priv *priv = spi_get_drvdata(spi);
391 if (mcp251x_is_2510(spi)) {
392 int i;
394 for (i = 1; i < TXBDAT_OFF + len; i++)
395 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + i,
396 buf[i]);
397 } else {
398 memcpy(priv->spi_tx_buf, buf, TXBDAT_OFF + len);
399 mcp251x_spi_trans(spi, TXBDAT_OFF + len);
403 static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame,
404 int tx_buf_idx)
406 struct mcp251x_priv *priv = spi_get_drvdata(spi);
407 u32 sid, eid, exide, rtr;
408 u8 buf[SPI_TRANSFER_BUF_LEN];
410 exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */
411 if (exide)
412 sid = (frame->can_id & CAN_EFF_MASK) >> 18;
413 else
414 sid = frame->can_id & CAN_SFF_MASK; /* Standard ID */
415 eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */
416 rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */
418 buf[TXBCTRL_OFF] = INSTRUCTION_LOAD_TXB(tx_buf_idx);
419 buf[TXBSIDH_OFF] = sid >> SIDH_SHIFT;
420 buf[TXBSIDL_OFF] = ((sid & SIDL_SID_MASK) << SIDL_SID_SHIFT) |
421 (exide << SIDL_EXIDE_SHIFT) |
422 ((eid >> SIDL_EID_SHIFT) & SIDL_EID_MASK);
423 buf[TXBEID8_OFF] = GET_BYTE(eid, 1);
424 buf[TXBEID0_OFF] = GET_BYTE(eid, 0);
425 buf[TXBDLC_OFF] = (rtr << DLC_RTR_SHIFT) | frame->can_dlc;
426 memcpy(buf + TXBDAT_OFF, frame->data, frame->can_dlc);
427 mcp251x_hw_tx_frame(spi, buf, frame->can_dlc, tx_buf_idx);
429 /* use INSTRUCTION_RTS, to avoid "repeated frame problem" */
430 priv->spi_tx_buf[0] = INSTRUCTION_RTS(1 << tx_buf_idx);
431 mcp251x_spi_trans(priv->spi, 1);
434 static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
435 int buf_idx)
437 struct mcp251x_priv *priv = spi_get_drvdata(spi);
439 if (mcp251x_is_2510(spi)) {
440 int i, len;
442 for (i = 1; i < RXBDAT_OFF; i++)
443 buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
445 len = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
446 for (; i < (RXBDAT_OFF + len); i++)
447 buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
448 } else {
449 priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);
450 mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);
451 memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);
455 static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
457 struct mcp251x_priv *priv = spi_get_drvdata(spi);
458 struct sk_buff *skb;
459 struct can_frame *frame;
460 u8 buf[SPI_TRANSFER_BUF_LEN];
462 skb = alloc_can_skb(priv->net, &frame);
463 if (!skb) {
464 dev_err(&spi->dev, "cannot allocate RX skb\n");
465 priv->net->stats.rx_dropped++;
466 return;
469 mcp251x_hw_rx_frame(spi, buf, buf_idx);
470 if (buf[RXBSIDL_OFF] & RXBSIDL_IDE) {
471 /* Extended ID format */
472 frame->can_id = CAN_EFF_FLAG;
473 frame->can_id |=
474 /* Extended ID part */
475 SET_BYTE(buf[RXBSIDL_OFF] & RXBSIDL_EID, 2) |
476 SET_BYTE(buf[RXBEID8_OFF], 1) |
477 SET_BYTE(buf[RXBEID0_OFF], 0) |
478 /* Standard ID part */
479 (((buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |
480 (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT)) << 18);
481 /* Remote transmission request */
482 if (buf[RXBDLC_OFF] & RXBDLC_RTR)
483 frame->can_id |= CAN_RTR_FLAG;
484 } else {
485 /* Standard ID format */
486 frame->can_id =
487 (buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |
488 (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT);
489 if (buf[RXBSIDL_OFF] & RXBSIDL_SRR)
490 frame->can_id |= CAN_RTR_FLAG;
492 /* Data length */
493 frame->can_dlc = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
494 memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc);
496 priv->net->stats.rx_packets++;
497 priv->net->stats.rx_bytes += frame->can_dlc;
499 can_led_event(priv->net, CAN_LED_EVENT_RX);
501 netif_rx_ni(skb);
504 static void mcp251x_hw_sleep(struct spi_device *spi)
506 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_SLEEP);
509 static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,
510 struct net_device *net)
512 struct mcp251x_priv *priv = netdev_priv(net);
513 struct spi_device *spi = priv->spi;
515 if (priv->tx_skb || priv->tx_len) {
516 dev_warn(&spi->dev, "hard_xmit called while tx busy\n");
517 return NETDEV_TX_BUSY;
520 if (can_dropped_invalid_skb(net, skb))
521 return NETDEV_TX_OK;
523 netif_stop_queue(net);
524 priv->tx_skb = skb;
525 queue_work(priv->wq, &priv->tx_work);
527 return NETDEV_TX_OK;
530 static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode)
532 struct mcp251x_priv *priv = netdev_priv(net);
534 switch (mode) {
535 case CAN_MODE_START:
536 mcp251x_clean(net);
537 /* We have to delay work since SPI I/O may sleep */
538 priv->can.state = CAN_STATE_ERROR_ACTIVE;
539 priv->restart_tx = 1;
540 if (priv->can.restart_ms == 0)
541 priv->after_suspend = AFTER_SUSPEND_RESTART;
542 queue_work(priv->wq, &priv->restart_work);
543 break;
544 default:
545 return -EOPNOTSUPP;
548 return 0;
551 static int mcp251x_set_normal_mode(struct spi_device *spi)
553 struct mcp251x_priv *priv = spi_get_drvdata(spi);
554 unsigned long timeout;
556 /* Enable interrupts */
557 mcp251x_write_reg(spi, CANINTE,
558 CANINTE_ERRIE | CANINTE_TX2IE | CANINTE_TX1IE |
559 CANINTE_TX0IE | CANINTE_RX1IE | CANINTE_RX0IE);
561 if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
562 /* Put device into loopback mode */
563 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LOOPBACK);
564 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
565 /* Put device into listen-only mode */
566 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LISTEN_ONLY);
567 } else {
568 /* Put device into normal mode */
569 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);
571 /* Wait for the device to enter normal mode */
572 timeout = jiffies + HZ;
573 while (mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) {
574 schedule();
575 if (time_after(jiffies, timeout)) {
576 dev_err(&spi->dev, "MCP251x didn't"
577 " enter in normal mode\n");
578 return -EBUSY;
582 priv->can.state = CAN_STATE_ERROR_ACTIVE;
583 return 0;
586 static int mcp251x_do_set_bittiming(struct net_device *net)
588 struct mcp251x_priv *priv = netdev_priv(net);
589 struct can_bittiming *bt = &priv->can.bittiming;
590 struct spi_device *spi = priv->spi;
592 mcp251x_write_reg(spi, CNF1, ((bt->sjw - 1) << CNF1_SJW_SHIFT) |
593 (bt->brp - 1));
594 mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE |
595 (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES ?
596 CNF2_SAM : 0) |
597 ((bt->phase_seg1 - 1) << CNF2_PS1_SHIFT) |
598 (bt->prop_seg - 1));
599 mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK,
600 (bt->phase_seg2 - 1));
601 dev_info(&spi->dev, "CNF: 0x%02x 0x%02x 0x%02x\n",
602 mcp251x_read_reg(spi, CNF1),
603 mcp251x_read_reg(spi, CNF2),
604 mcp251x_read_reg(spi, CNF3));
606 return 0;
609 static int mcp251x_setup(struct net_device *net, struct mcp251x_priv *priv,
610 struct spi_device *spi)
612 mcp251x_do_set_bittiming(net);
614 mcp251x_write_reg(spi, RXBCTRL(0),
615 RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1);
616 mcp251x_write_reg(spi, RXBCTRL(1),
617 RXBCTRL_RXM0 | RXBCTRL_RXM1);
618 return 0;
621 static int mcp251x_hw_reset(struct spi_device *spi)
623 struct mcp251x_priv *priv = spi_get_drvdata(spi);
624 int ret;
625 unsigned long timeout;
627 priv->spi_tx_buf[0] = INSTRUCTION_RESET;
628 ret = spi_write(spi, priv->spi_tx_buf, 1);
629 if (ret) {
630 dev_err(&spi->dev, "reset failed: ret = %d\n", ret);
631 return -EIO;
634 /* Wait for reset to finish */
635 timeout = jiffies + HZ;
636 mdelay(10);
637 while ((mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK)
638 != CANCTRL_REQOP_CONF) {
639 schedule();
640 if (time_after(jiffies, timeout)) {
641 dev_err(&spi->dev, "MCP251x didn't"
642 " enter in conf mode after reset\n");
643 return -EBUSY;
646 return 0;
649 static int mcp251x_hw_probe(struct spi_device *spi)
651 int st1, st2;
653 mcp251x_hw_reset(spi);
656 * Please note that these are "magic values" based on after
657 * reset defaults taken from data sheet which allows us to see
658 * if we really have a chip on the bus (we avoid common all
659 * zeroes or all ones situations)
661 st1 = mcp251x_read_reg(spi, CANSTAT) & 0xEE;
662 st2 = mcp251x_read_reg(spi, CANCTRL) & 0x17;
664 dev_dbg(&spi->dev, "CANSTAT 0x%02x CANCTRL 0x%02x\n", st1, st2);
666 /* Check for power up default values */
667 return (st1 == 0x80 && st2 == 0x07) ? 1 : 0;
670 static int mcp251x_power_enable(struct regulator *reg, int enable)
672 if (IS_ERR(reg))
673 return 0;
675 if (enable)
676 return regulator_enable(reg);
677 else
678 return regulator_disable(reg);
681 static void mcp251x_open_clean(struct net_device *net)
683 struct mcp251x_priv *priv = netdev_priv(net);
684 struct spi_device *spi = priv->spi;
686 free_irq(spi->irq, priv);
687 mcp251x_hw_sleep(spi);
688 mcp251x_power_enable(priv->transceiver, 0);
689 close_candev(net);
692 static int mcp251x_stop(struct net_device *net)
694 struct mcp251x_priv *priv = netdev_priv(net);
695 struct spi_device *spi = priv->spi;
697 close_candev(net);
699 priv->force_quit = 1;
700 free_irq(spi->irq, priv);
701 destroy_workqueue(priv->wq);
702 priv->wq = NULL;
704 mutex_lock(&priv->mcp_lock);
706 /* Disable and clear pending interrupts */
707 mcp251x_write_reg(spi, CANINTE, 0x00);
708 mcp251x_write_reg(spi, CANINTF, 0x00);
710 mcp251x_write_reg(spi, TXBCTRL(0), 0);
711 mcp251x_clean(net);
713 mcp251x_hw_sleep(spi);
715 mcp251x_power_enable(priv->transceiver, 0);
717 priv->can.state = CAN_STATE_STOPPED;
719 mutex_unlock(&priv->mcp_lock);
721 can_led_event(net, CAN_LED_EVENT_STOP);
723 return 0;
726 static void mcp251x_error_skb(struct net_device *net, int can_id, int data1)
728 struct sk_buff *skb;
729 struct can_frame *frame;
731 skb = alloc_can_err_skb(net, &frame);
732 if (skb) {
733 frame->can_id |= can_id;
734 frame->data[1] = data1;
735 netif_rx_ni(skb);
736 } else {
737 netdev_err(net, "cannot allocate error skb\n");
741 static void mcp251x_tx_work_handler(struct work_struct *ws)
743 struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
744 tx_work);
745 struct spi_device *spi = priv->spi;
746 struct net_device *net = priv->net;
747 struct can_frame *frame;
749 mutex_lock(&priv->mcp_lock);
750 if (priv->tx_skb) {
751 if (priv->can.state == CAN_STATE_BUS_OFF) {
752 mcp251x_clean(net);
753 } else {
754 frame = (struct can_frame *)priv->tx_skb->data;
756 if (frame->can_dlc > CAN_FRAME_MAX_DATA_LEN)
757 frame->can_dlc = CAN_FRAME_MAX_DATA_LEN;
758 mcp251x_hw_tx(spi, frame, 0);
759 priv->tx_len = 1 + frame->can_dlc;
760 can_put_echo_skb(priv->tx_skb, net, 0);
761 priv->tx_skb = NULL;
764 mutex_unlock(&priv->mcp_lock);
767 static void mcp251x_restart_work_handler(struct work_struct *ws)
769 struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
770 restart_work);
771 struct spi_device *spi = priv->spi;
772 struct net_device *net = priv->net;
774 mutex_lock(&priv->mcp_lock);
775 if (priv->after_suspend) {
776 mdelay(10);
777 mcp251x_hw_reset(spi);
778 mcp251x_setup(net, priv, spi);
779 if (priv->after_suspend & AFTER_SUSPEND_RESTART) {
780 mcp251x_set_normal_mode(spi);
781 } else if (priv->after_suspend & AFTER_SUSPEND_UP) {
782 netif_device_attach(net);
783 mcp251x_clean(net);
784 mcp251x_set_normal_mode(spi);
785 netif_wake_queue(net);
786 } else {
787 mcp251x_hw_sleep(spi);
789 priv->after_suspend = 0;
790 priv->force_quit = 0;
793 if (priv->restart_tx) {
794 priv->restart_tx = 0;
795 mcp251x_write_reg(spi, TXBCTRL(0), 0);
796 mcp251x_clean(net);
797 netif_wake_queue(net);
798 mcp251x_error_skb(net, CAN_ERR_RESTARTED, 0);
800 mutex_unlock(&priv->mcp_lock);
803 static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
805 struct mcp251x_priv *priv = dev_id;
806 struct spi_device *spi = priv->spi;
807 struct net_device *net = priv->net;
809 mutex_lock(&priv->mcp_lock);
810 while (!priv->force_quit) {
811 enum can_state new_state;
812 u8 intf, eflag;
813 u8 clear_intf = 0;
814 int can_id = 0, data1 = 0;
816 mcp251x_read_2regs(spi, CANINTF, &intf, &eflag);
818 /* mask out flags we don't care about */
819 intf &= CANINTF_RX | CANINTF_TX | CANINTF_ERR;
821 /* receive buffer 0 */
822 if (intf & CANINTF_RX0IF) {
823 mcp251x_hw_rx(spi, 0);
825 * Free one buffer ASAP
826 * (The MCP2515 does this automatically.)
828 if (mcp251x_is_2510(spi))
829 mcp251x_write_bits(spi, CANINTF, CANINTF_RX0IF, 0x00);
832 /* receive buffer 1 */
833 if (intf & CANINTF_RX1IF) {
834 mcp251x_hw_rx(spi, 1);
835 /* the MCP2515 does this automatically */
836 if (mcp251x_is_2510(spi))
837 clear_intf |= CANINTF_RX1IF;
840 /* any error or tx interrupt we need to clear? */
841 if (intf & (CANINTF_ERR | CANINTF_TX))
842 clear_intf |= intf & (CANINTF_ERR | CANINTF_TX);
843 if (clear_intf)
844 mcp251x_write_bits(spi, CANINTF, clear_intf, 0x00);
846 if (eflag)
847 mcp251x_write_bits(spi, EFLG, eflag, 0x00);
849 /* Update can state */
850 if (eflag & EFLG_TXBO) {
851 new_state = CAN_STATE_BUS_OFF;
852 can_id |= CAN_ERR_BUSOFF;
853 } else if (eflag & EFLG_TXEP) {
854 new_state = CAN_STATE_ERROR_PASSIVE;
855 can_id |= CAN_ERR_CRTL;
856 data1 |= CAN_ERR_CRTL_TX_PASSIVE;
857 } else if (eflag & EFLG_RXEP) {
858 new_state = CAN_STATE_ERROR_PASSIVE;
859 can_id |= CAN_ERR_CRTL;
860 data1 |= CAN_ERR_CRTL_RX_PASSIVE;
861 } else if (eflag & EFLG_TXWAR) {
862 new_state = CAN_STATE_ERROR_WARNING;
863 can_id |= CAN_ERR_CRTL;
864 data1 |= CAN_ERR_CRTL_TX_WARNING;
865 } else if (eflag & EFLG_RXWAR) {
866 new_state = CAN_STATE_ERROR_WARNING;
867 can_id |= CAN_ERR_CRTL;
868 data1 |= CAN_ERR_CRTL_RX_WARNING;
869 } else {
870 new_state = CAN_STATE_ERROR_ACTIVE;
873 /* Update can state statistics */
874 switch (priv->can.state) {
875 case CAN_STATE_ERROR_ACTIVE:
876 if (new_state >= CAN_STATE_ERROR_WARNING &&
877 new_state <= CAN_STATE_BUS_OFF)
878 priv->can.can_stats.error_warning++;
879 case CAN_STATE_ERROR_WARNING: /* fallthrough */
880 if (new_state >= CAN_STATE_ERROR_PASSIVE &&
881 new_state <= CAN_STATE_BUS_OFF)
882 priv->can.can_stats.error_passive++;
883 break;
884 default:
885 break;
887 priv->can.state = new_state;
889 if (intf & CANINTF_ERRIF) {
890 /* Handle overflow counters */
891 if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) {
892 if (eflag & EFLG_RX0OVR) {
893 net->stats.rx_over_errors++;
894 net->stats.rx_errors++;
896 if (eflag & EFLG_RX1OVR) {
897 net->stats.rx_over_errors++;
898 net->stats.rx_errors++;
900 can_id |= CAN_ERR_CRTL;
901 data1 |= CAN_ERR_CRTL_RX_OVERFLOW;
903 mcp251x_error_skb(net, can_id, data1);
906 if (priv->can.state == CAN_STATE_BUS_OFF) {
907 if (priv->can.restart_ms == 0) {
908 priv->force_quit = 1;
909 can_bus_off(net);
910 mcp251x_hw_sleep(spi);
911 break;
915 if (intf == 0)
916 break;
918 if (intf & CANINTF_TX) {
919 net->stats.tx_packets++;
920 net->stats.tx_bytes += priv->tx_len - 1;
921 can_led_event(net, CAN_LED_EVENT_TX);
922 if (priv->tx_len) {
923 can_get_echo_skb(net, 0);
924 priv->tx_len = 0;
926 netif_wake_queue(net);
930 mutex_unlock(&priv->mcp_lock);
931 return IRQ_HANDLED;
934 static int mcp251x_open(struct net_device *net)
936 struct mcp251x_priv *priv = netdev_priv(net);
937 struct spi_device *spi = priv->spi;
938 unsigned long flags = IRQF_ONESHOT | IRQF_TRIGGER_FALLING;
939 int ret;
941 ret = open_candev(net);
942 if (ret) {
943 dev_err(&spi->dev, "unable to set initial baudrate!\n");
944 return ret;
947 mutex_lock(&priv->mcp_lock);
948 mcp251x_power_enable(priv->transceiver, 1);
950 priv->force_quit = 0;
951 priv->tx_skb = NULL;
952 priv->tx_len = 0;
954 ret = request_threaded_irq(spi->irq, NULL, mcp251x_can_ist,
955 flags, DEVICE_NAME, priv);
956 if (ret) {
957 dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
958 mcp251x_power_enable(priv->transceiver, 0);
959 close_candev(net);
960 goto open_unlock;
963 priv->wq = create_freezable_workqueue("mcp251x_wq");
964 INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
965 INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
967 ret = mcp251x_hw_reset(spi);
968 if (ret) {
969 mcp251x_open_clean(net);
970 goto open_unlock;
972 ret = mcp251x_setup(net, priv, spi);
973 if (ret) {
974 mcp251x_open_clean(net);
975 goto open_unlock;
977 ret = mcp251x_set_normal_mode(spi);
978 if (ret) {
979 mcp251x_open_clean(net);
980 goto open_unlock;
983 can_led_event(net, CAN_LED_EVENT_OPEN);
985 netif_wake_queue(net);
987 open_unlock:
988 mutex_unlock(&priv->mcp_lock);
989 return ret;
992 static const struct net_device_ops mcp251x_netdev_ops = {
993 .ndo_open = mcp251x_open,
994 .ndo_stop = mcp251x_stop,
995 .ndo_start_xmit = mcp251x_hard_start_xmit,
998 static int mcp251x_can_probe(struct spi_device *spi)
1000 struct net_device *net;
1001 struct mcp251x_priv *priv;
1002 struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1003 int ret = -ENODEV;
1005 if (!pdata)
1006 /* Platform data is required for osc freq */
1007 goto error_out;
1009 /* Allocate can/net device */
1010 net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX);
1011 if (!net) {
1012 ret = -ENOMEM;
1013 goto error_alloc;
1016 net->netdev_ops = &mcp251x_netdev_ops;
1017 net->flags |= IFF_ECHO;
1019 priv = netdev_priv(net);
1020 priv->can.bittiming_const = &mcp251x_bittiming_const;
1021 priv->can.do_set_mode = mcp251x_do_set_mode;
1022 priv->can.clock.freq = pdata->oscillator_frequency / 2;
1023 priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
1024 CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY;
1025 priv->model = spi_get_device_id(spi)->driver_data;
1026 priv->net = net;
1028 priv->power = devm_regulator_get(&spi->dev, "vdd");
1029 priv->transceiver = devm_regulator_get(&spi->dev, "xceiver");
1030 if ((PTR_ERR(priv->power) == -EPROBE_DEFER) ||
1031 (PTR_ERR(priv->transceiver) == -EPROBE_DEFER)) {
1032 ret = -EPROBE_DEFER;
1033 goto error_power;
1036 ret = mcp251x_power_enable(priv->power, 1);
1037 if (ret)
1038 goto error_power;
1040 spi_set_drvdata(spi, priv);
1042 priv->spi = spi;
1043 mutex_init(&priv->mcp_lock);
1045 /* If requested, allocate DMA buffers */
1046 if (mcp251x_enable_dma) {
1047 spi->dev.coherent_dma_mask = ~0;
1050 * Minimum coherent DMA allocation is PAGE_SIZE, so allocate
1051 * that much and share it between Tx and Rx DMA buffers.
1053 priv->spi_tx_buf = dma_alloc_coherent(&spi->dev,
1054 PAGE_SIZE,
1055 &priv->spi_tx_dma,
1056 GFP_DMA);
1058 if (priv->spi_tx_buf) {
1059 priv->spi_rx_buf = (priv->spi_tx_buf + (PAGE_SIZE / 2));
1060 priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
1061 (PAGE_SIZE / 2));
1062 } else {
1063 /* Fall back to non-DMA */
1064 mcp251x_enable_dma = 0;
1068 /* Allocate non-DMA buffers */
1069 if (!mcp251x_enable_dma) {
1070 priv->spi_tx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
1071 if (!priv->spi_tx_buf) {
1072 ret = -ENOMEM;
1073 goto error_tx_buf;
1075 priv->spi_rx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
1076 if (!priv->spi_rx_buf) {
1077 ret = -ENOMEM;
1078 goto error_rx_buf;
1082 SET_NETDEV_DEV(net, &spi->dev);
1084 /* Configure the SPI bus */
1085 spi->mode = spi->mode ? : SPI_MODE_0;
1086 if (mcp251x_is_2510(spi))
1087 spi->max_speed_hz = spi->max_speed_hz ? : 5 * 1000 * 1000;
1088 else
1089 spi->max_speed_hz = spi->max_speed_hz ? : 10 * 1000 * 1000;
1090 spi->bits_per_word = 8;
1091 spi_setup(spi);
1093 /* Here is OK to not lock the MCP, no one knows about it yet */
1094 if (!mcp251x_hw_probe(spi)) {
1095 ret = -ENODEV;
1096 goto error_probe;
1098 mcp251x_hw_sleep(spi);
1100 ret = register_candev(net);
1101 if (ret)
1102 goto error_probe;
1104 devm_can_led_init(net);
1106 dev_info(&spi->dev, "probed\n");
1108 return ret;
1110 error_probe:
1111 if (!mcp251x_enable_dma)
1112 kfree(priv->spi_rx_buf);
1113 error_rx_buf:
1114 if (!mcp251x_enable_dma)
1115 kfree(priv->spi_tx_buf);
1116 error_tx_buf:
1117 if (mcp251x_enable_dma)
1118 dma_free_coherent(&spi->dev, PAGE_SIZE,
1119 priv->spi_tx_buf, priv->spi_tx_dma);
1120 mcp251x_power_enable(priv->power, 0);
1121 error_power:
1122 free_candev(net);
1123 error_alloc:
1124 dev_err(&spi->dev, "probe failed\n");
1125 error_out:
1126 return ret;
1129 static int mcp251x_can_remove(struct spi_device *spi)
1131 struct mcp251x_priv *priv = spi_get_drvdata(spi);
1132 struct net_device *net = priv->net;
1134 unregister_candev(net);
1136 if (mcp251x_enable_dma) {
1137 dma_free_coherent(&spi->dev, PAGE_SIZE,
1138 priv->spi_tx_buf, priv->spi_tx_dma);
1139 } else {
1140 kfree(priv->spi_tx_buf);
1141 kfree(priv->spi_rx_buf);
1144 mcp251x_power_enable(priv->power, 0);
1146 free_candev(net);
1148 return 0;
1151 #ifdef CONFIG_PM_SLEEP
1153 static int mcp251x_can_suspend(struct device *dev)
1155 struct spi_device *spi = to_spi_device(dev);
1156 struct mcp251x_priv *priv = spi_get_drvdata(spi);
1157 struct net_device *net = priv->net;
1159 priv->force_quit = 1;
1160 disable_irq(spi->irq);
1162 * Note: at this point neither IST nor workqueues are running.
1163 * open/stop cannot be called anyway so locking is not needed
1165 if (netif_running(net)) {
1166 netif_device_detach(net);
1168 mcp251x_hw_sleep(spi);
1169 mcp251x_power_enable(priv->transceiver, 0);
1170 priv->after_suspend = AFTER_SUSPEND_UP;
1171 } else {
1172 priv->after_suspend = AFTER_SUSPEND_DOWN;
1175 if (!IS_ERR(priv->power)) {
1176 regulator_disable(priv->power);
1177 priv->after_suspend |= AFTER_SUSPEND_POWER;
1180 return 0;
1183 static int mcp251x_can_resume(struct device *dev)
1185 struct spi_device *spi = to_spi_device(dev);
1186 struct mcp251x_priv *priv = spi_get_drvdata(spi);
1188 if (priv->after_suspend & AFTER_SUSPEND_POWER) {
1189 mcp251x_power_enable(priv->power, 1);
1190 queue_work(priv->wq, &priv->restart_work);
1191 } else {
1192 if (priv->after_suspend & AFTER_SUSPEND_UP) {
1193 mcp251x_power_enable(priv->transceiver, 1);
1194 queue_work(priv->wq, &priv->restart_work);
1195 } else {
1196 priv->after_suspend = 0;
1199 priv->force_quit = 0;
1200 enable_irq(spi->irq);
1201 return 0;
1203 #endif
1205 static SIMPLE_DEV_PM_OPS(mcp251x_can_pm_ops, mcp251x_can_suspend,
1206 mcp251x_can_resume);
1208 static const struct spi_device_id mcp251x_id_table[] = {
1209 { "mcp2510", CAN_MCP251X_MCP2510 },
1210 { "mcp2515", CAN_MCP251X_MCP2515 },
1211 { },
1214 MODULE_DEVICE_TABLE(spi, mcp251x_id_table);
1216 static struct spi_driver mcp251x_can_driver = {
1217 .driver = {
1218 .name = DEVICE_NAME,
1219 .owner = THIS_MODULE,
1220 .pm = &mcp251x_can_pm_ops,
1223 .id_table = mcp251x_id_table,
1224 .probe = mcp251x_can_probe,
1225 .remove = mcp251x_can_remove,
1227 module_spi_driver(mcp251x_can_driver);
1229 MODULE_AUTHOR("Chris Elston <celston@katalix.com>, "
1230 "Christian Pellegrin <chripell@evolware.org>");
1231 MODULE_DESCRIPTION("Microchip 251x CAN driver");
1232 MODULE_LICENSE("GPL v2");