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Applied patch from Christian Pellegrin
[socketcan-devel.git] / kernel / 2.6 / drivers / net / can / mcp251x.c
1 /*
2  *
3  * CAN bus driver for Microchip 251x CAN Controller with SPI Interface
4  *
5  * MCP2510 support and bug fixes by Christian Pellegrin
6  * <chripell@evolware.org>
7  *
8  * Copyright 2007 Raymarine UK, Ltd. All Rights Reserved.
9  * Written under contract by:
10  *   Chris Elston, Katalix Systems, Ltd.
11  *
12  * Based on Microchip MCP251x CAN controller driver written by
13  * David Vrabel, Copyright 2006 Arcom Control Systems Ltd.
14  *
15  * Based on CAN bus driver for the CCAN controller written by
16  * - Sascha Hauer, Marc Kleine-Budde, Pengutronix
17  * - Simon Kallweit, intefo AG
18  * Copyright 2007
19  *
20  * This program is free software; you can redistribute it and/or modify
21  * it under the terms of the version 2 of the GNU General Public License
22  * as published by the Free Software Foundation
23  *
24  * This program is distributed in the hope that it will be useful,
25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27  * GNU General Public License for more details.
28  *
29  * You should have received a copy of the GNU General Public License
30  * along with this program; if not, write to the Free Software
31  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
32  *
33  *
34  *
35  * Your platform definition file should specify something like:
36  *
37  * static struct mcp251x_platform_data mcp251x_info = {
38  *       .oscillator_frequency = 8000000,
39  *       .board_specific_setup = &mcp251x_setup,
40  *       .model = CAN_MCP251X_MCP2510,
41  *       .power_enable = mcp251x_power_enable,
42  *       .transceiver_enable = NULL,
43  * };
44  *
45  * static struct spi_board_info spi_board_info[] = {
46  *         {
47  *                 .modalias      = "mcp251x",
48  *                 .platform_data = &mcp251x_info,
49  *                 .irq           = IRQ_EINT13,
50  *                 .max_speed_hz  = 2*1000*1000,
51  *                 .chip_select   = 2,
52  *         },
53  * };
54  *
55  * Please see mcp251x.h for a description of the fields in
56  * struct mcp251x_platform_data.
57  *
58  */
59
60 #include <linux/device.h>
61 #include <linux/kernel.h>
62 #include <linux/module.h>
63 #include <linux/interrupt.h>
64 #include <linux/platform_device.h>
65 #include <linux/netdevice.h>
66 #include <linux/can.h>
67 #include <linux/spi/spi.h>
68 #include <linux/can/dev.h>
69 #include <linux/can/core.h>
70 #include <linux/if_arp.h>
71 #include <linux/dma-mapping.h>
72 #include <linux/delay.h>
73 #include <linux/completion.h>
74 #include <linux/freezer.h>
75 #include <linux/uaccess.h>
76 #include <linux/io.h>
77 #include <linux/can/mcp251x.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
87 /* MPC251x registers */
88 #define CANSTAT       0x0e
89 #define CANCTRL       0x0f
90 #  define CANCTRL_REQOP_MASK        0xe0
91 #  define CANCTRL_REQOP_CONF        0x80
92 #  define CANCTRL_REQOP_LISTEN_ONLY 0x60
93 #  define CANCTRL_REQOP_LOOPBACK    0x40
94 #  define CANCTRL_REQOP_SLEEP       0x20
95 #  define CANCTRL_REQOP_NORMAL      0x00
96 #  define CANCTRL_OSM               0x08
97 #  define CANCTRL_ABAT              0x10
98 #define TEC           0x1c
99 #define REC           0x1d
100 #define CNF1          0x2a
101 #define CNF2          0x29
102 #  define CNF2_BTLMODE  0x80
103 #define CNF3          0x28
104 #  define CNF3_SOF      0x08
105 #  define CNF3_WAKFIL   0x04
106 #  define CNF3_PHSEG2_MASK 0x07
107 #define CANINTE       0x2b
108 #  define CANINTE_MERRE 0x80
109 #  define CANINTE_WAKIE 0x40
110 #  define CANINTE_ERRIE 0x20
111 #  define CANINTE_TX2IE 0x10
112 #  define CANINTE_TX1IE 0x08
113 #  define CANINTE_TX0IE 0x04
114 #  define CANINTE_RX1IE 0x02
115 #  define CANINTE_RX0IE 0x01
116 #define CANINTF       0x2c
117 #  define CANINTF_MERRF 0x80
118 #  define CANINTF_WAKIF 0x40
119 #  define CANINTF_ERRIF 0x20
120 #  define CANINTF_TX2IF 0x10
121 #  define CANINTF_TX1IF 0x08
122 #  define CANINTF_TX0IF 0x04
123 #  define CANINTF_RX1IF 0x02
124 #  define CANINTF_RX0IF 0x01
125 #define EFLG          0x2d
126 #  define EFLG_EWARN    0x01
127 #  define EFLG_RXWAR    0x02
128 #  define EFLG_TXWAR    0x04
129 #  define EFLG_RXEP     0x08
130 #  define EFLG_TXEP     0x10
131 #  define EFLG_TXBO     0x20
132 #  define EFLG_RX0OVR   0x40
133 #  define EFLG_RX1OVR   0x80
134 #define TXBCTRL(n)  ((n * 0x10) + 0x30)
135 #  define TXBCTRL_ABTF  0x40
136 #  define TXBCTRL_MLOA  0x20
137 #  define TXBCTRL_TXERR 0x10
138 #  define TXBCTRL_TXREQ 0x08
139 #define RXBCTRL(n)  ((n * 0x10) + 0x60)
140 #  define RXBCTRL_BUKT   0x04
141 #  define RXBCTRL_RXM0   0x20
142 #  define RXBCTRL_RXM1   0x40
143
144 /* Buffer size required for the largest SPI transfer (i.e., reading a
145  * frame). */
146 #define CAN_FRAME_MAX_DATA_LEN  8
147 #define SPI_TRANSFER_BUF_LEN    (2*(6 + CAN_FRAME_MAX_DATA_LEN))
148 #define CAN_FRAME_MAX_BITS      128
149
150 #define DEVICE_NAME "mcp251x"
151
152 static int enable_dma; /* Enable SPI DMA. Default: 0 (Off) */
153 module_param(enable_dma, int, S_IRUGO);
154 MODULE_PARM_DESC(enable_dma, "Enable SPI DMA. Default: 0 (Off)");
155
156 static struct can_bittiming_const mcp251x_bittiming_const = {
157         .tseg1_min = 3,
158         .tseg1_max = 16,
159         .tseg2_min = 2,
160         .tseg2_max = 8,
161         .sjw_max = 4,
162         .brp_min = 1,
163         .brp_max = 64,
164         .brp_inc = 1,
165 };
166
167 struct mcp251x_priv {
168         struct can_priv    can;
169         struct net_device *net;
170         struct spi_device *spi;
171
172         struct mutex spi_lock; /* SPI buffer lock */
173         u8 *spi_tx_buf;
174         u8 *spi_rx_buf;
175         dma_addr_t spi_tx_dma;
176         dma_addr_t spi_rx_dma;
177
178         struct sk_buff *tx_skb;
179         struct workqueue_struct *wq;
180         struct work_struct tx_work;
181         struct work_struct irq_work;
182         struct completion awake;
183         int wake;
184         int force_quit;
185         int after_suspend;
186 #define AFTER_SUSPEND_UP 1
187 #define AFTER_SUSPEND_DOWN 2
188 #define AFTER_SUSPEND_POWER 4
189         int restart_tx;
190 };
191
192 static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
193 {
194         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
195         struct spi_transfer t = {
196                 .tx_buf = priv->spi_tx_buf,
197                 .rx_buf = priv->spi_rx_buf,
198                 .len = 3,
199                 .cs_change = 0,
200         };
201         struct spi_message m;
202         u8 val = 0;
203         int ret;
204
205         mutex_lock(&priv->spi_lock);
206
207         priv->spi_tx_buf[0] = INSTRUCTION_READ;
208         priv->spi_tx_buf[1] = reg;
209
210         spi_message_init(&m);
211
212         if (enable_dma) {
213                 t.tx_dma = priv->spi_tx_dma;
214                 t.rx_dma = priv->spi_rx_dma;
215                 m.is_dma_mapped = 1;
216         }
217
218         spi_message_add_tail(&t, &m);
219
220         ret = spi_sync(spi, &m);
221         if (ret < 0)
222                 dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __func__, ret);
223         else
224                 val = priv->spi_rx_buf[2];
225
226         mutex_unlock(&priv->spi_lock);
227
228         dev_dbg(&spi->dev, "%s: read %02x = %02x\n", __func__, reg, val);
229         return val;
230 }
231
232 static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val)
233 {
234         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
235         struct spi_transfer t = {
236                 .tx_buf = priv->spi_tx_buf,
237                 .rx_buf = priv->spi_rx_buf,
238                 .len = 3,
239                 .cs_change = 0,
240         };
241         struct spi_message m;
242         int ret;
243
244         mutex_lock(&priv->spi_lock);
245
246         priv->spi_tx_buf[0] = INSTRUCTION_WRITE;
247         priv->spi_tx_buf[1] = reg;
248         priv->spi_tx_buf[2] = val;
249
250         spi_message_init(&m);
251
252         if (enable_dma) {
253                 t.tx_dma = priv->spi_tx_dma;
254                 t.rx_dma = priv->spi_rx_dma;
255                 m.is_dma_mapped = 1;
256         }
257
258         spi_message_add_tail(&t, &m);
259
260         ret = spi_sync(spi, &m);
261
262         mutex_unlock(&priv->spi_lock);
263
264         if (ret < 0)
265                 dev_dbg(&spi->dev, "%s: failed\n", __func__);
266 }
267
268 static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
269                                u8 mask, uint8_t val)
270 {
271         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
272         struct spi_transfer t = {
273                 .tx_buf = priv->spi_tx_buf,
274                 .rx_buf = priv->spi_rx_buf,
275                 .len = 4,
276                 .cs_change = 0,
277         };
278         struct spi_message m;
279         int ret;
280
281         mutex_lock(&priv->spi_lock);
282
283         priv->spi_tx_buf[0] = INSTRUCTION_BIT_MODIFY;
284         priv->spi_tx_buf[1] = reg;
285         priv->spi_tx_buf[2] = mask;
286         priv->spi_tx_buf[3] = val;
287
288         spi_message_init(&m);
289
290         if (enable_dma) {
291                 t.tx_dma = priv->spi_tx_dma;
292                 t.rx_dma = priv->spi_rx_dma;
293                 m.is_dma_mapped = 1;
294         }
295
296         spi_message_add_tail(&t, &m);
297
298         ret = spi_sync(spi, &m);
299
300         mutex_unlock(&priv->spi_lock);
301
302         if (ret < 0)
303                 dev_dbg(&spi->dev, "%s: failed\n", __func__);
304 }
305
306 static int mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame,
307                           int tx_buf_idx)
308 {
309         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
310         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
311         u32 sid, eid, exide, rtr;
312
313         dev_dbg(&spi->dev, "%s\n", __func__);
314
315         exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */
316         if (exide)
317                 sid = (frame->can_id & CAN_EFF_MASK) >> 18;
318         else
319                 sid = frame->can_id & CAN_SFF_MASK; /* Standard ID */
320         eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */
321         rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */
322
323         if (pdata->model == CAN_MCP251X_MCP2510) {
324                 int i;
325
326                 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + 1, sid >> 3);
327                 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + 2,
328                                   ((sid & 7) << 5) | (exide << 3) |
329                                   ((eid >> 16) & 3));
330                 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + 3,
331                                   (eid >> 8) & 0xff);
332                 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + 4, eid & 0xff);
333                 mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + 5,
334                                   (rtr << 6) | frame->can_dlc);
335
336                 for (i = 0; i < frame->can_dlc ; i++) {
337                         mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + 6 + i,
338                                           frame->data[i]);
339                 }
340         } else {
341                 struct spi_transfer t = {
342                         .tx_buf = priv->spi_tx_buf,
343                         .rx_buf = priv->spi_rx_buf,
344                         .cs_change = 0,
345                         .len = 6 + CAN_FRAME_MAX_DATA_LEN,
346                 };
347                 struct spi_message m;
348                 int ret;
349                 u8 *tx_buf = priv->spi_tx_buf;
350
351                 mutex_lock(&priv->spi_lock);
352
353                 tx_buf[0] = INSTRUCTION_LOAD_TXB(tx_buf_idx);
354                 tx_buf[1] = sid >> 3;
355                 tx_buf[2] = ((sid & 7) << 5) | (exide << 3) |
356                   ((eid >> 16) & 3);
357                 tx_buf[3] = (eid >> 8) & 0xff;
358                 tx_buf[4] = eid & 0xff;
359                 tx_buf[5] = (rtr << 6) | frame->can_dlc;
360
361                 memcpy(tx_buf + 6, frame->data, frame->can_dlc);
362
363                 spi_message_init(&m);
364
365                 if (enable_dma) {
366                         t.tx_dma = priv->spi_tx_dma;
367                         t.rx_dma = priv->spi_rx_dma;
368                         m.is_dma_mapped = 1;
369                 }
370
371                 spi_message_add_tail(&t, &m);
372
373                 ret = spi_sync(spi, &m);
374
375                 mutex_unlock(&priv->spi_lock);
376
377                 if (ret < 0) {
378                         dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __func__,
379                                 ret);
380                         return -1;
381                 }
382         }
383         mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx), TXBCTRL_TXREQ);
384         return 0;
385 }
386
387 static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
388 {
389         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
390         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
391         struct sk_buff *skb;
392         struct can_frame *frame;
393
394         dev_dbg(&spi->dev, "%s\n", __func__);
395
396         skb = dev_alloc_skb(sizeof(struct can_frame));
397         if (!skb) {
398                 dev_dbg(&spi->dev, "%s: out of memory for Rx'd frame\n",
399                         __func__);
400                 priv->net->stats.rx_dropped++;
401                 return;
402         }
403         skb->dev = priv->net;
404         frame = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
405
406         if (pdata->model == CAN_MCP251X_MCP2510) {
407                 int i;
408                 u8 rx_buf[6];
409
410                 rx_buf[1] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + 1);
411                 rx_buf[2] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + 2);
412                 rx_buf[3] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + 3);
413                 rx_buf[4] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + 4);
414                 rx_buf[5] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + 5);
415
416                 if ((rx_buf[2] >> 3) & 0x1) {
417                         /* Extended ID format */
418                         frame->can_id = CAN_EFF_FLAG;
419                         frame->can_id |= ((rx_buf[2] & 3) << 16) |
420                           (rx_buf[3] << 8) | rx_buf[4] |
421                           (((rx_buf[1] << 3) | (rx_buf[2] >> 5)) << 18);
422                 } else {
423                         /* Standard ID format */
424                         frame->can_id = (rx_buf[1] << 3) | (rx_buf[2] >> 5);
425                 }
426
427                 if ((rx_buf[5] >> 6) & 0x1) {
428                         /* Remote transmission request */
429                         frame->can_id |= CAN_RTR_FLAG;
430                 }
431
432                 /* Data length */
433                 frame->can_dlc = rx_buf[5] & 0x0f;
434                 if (frame->can_dlc > 8) {
435                         dev_warn(&spi->dev, "invalid frame recevied\n");
436                         priv->net->stats.rx_errors++;
437                         dev_kfree_skb(skb);
438                         return;
439                 }
440
441                 for (i = 0; i < frame->can_dlc; i++) {
442                         frame->data[i] = mcp251x_read_reg(spi,
443                                                           RXBCTRL(buf_idx) +
444                                                           6 + i);
445                 }
446         } else {
447                 struct spi_transfer t = {
448                         .tx_buf = priv->spi_tx_buf,
449                         .rx_buf = priv->spi_rx_buf,
450                         .cs_change = 0,
451                         .len = 14, /* RX buffer: RXBnCTRL to RXBnD7 */
452                 };
453                 struct spi_message m;
454                 int ret;
455                 u8 *tx_buf = priv->spi_tx_buf;
456                 u8 *rx_buf = priv->spi_rx_buf;
457
458                 mutex_lock(&priv->spi_lock);
459
460                 tx_buf[0] = INSTRUCTION_READ_RXB(buf_idx);
461
462                 spi_message_init(&m);
463
464                 if (enable_dma) {
465                         t.tx_dma = priv->spi_tx_dma;
466                         t.rx_dma = priv->spi_rx_dma;
467                         m.is_dma_mapped = 1;
468                 }
469
470                 spi_message_add_tail(&t, &m);
471
472                 ret = spi_sync(spi, &m);
473
474                 if (ret < 0) {
475                         dev_dbg(&spi->dev, "%s: failed: ret = %d\n",
476                                 __func__, ret);
477                         priv->net->stats.rx_errors++;
478                         mutex_unlock(&priv->spi_lock);
479                         return;
480                 }
481
482                 if ((rx_buf[2] >> 3) & 0x1) {
483                         /* Extended ID format */
484                         frame->can_id = CAN_EFF_FLAG;
485                         frame->can_id |= ((rx_buf[2] & 3) << 16) |
486                           (rx_buf[3] << 8) | rx_buf[4] |
487                           (((rx_buf[1] << 3) | (rx_buf[2] >> 5)) << 18);
488                 } else {
489                         /* Standard ID format */
490                         frame->can_id = (rx_buf[1] << 3) | (rx_buf[2] >> 5);
491                 }
492
493                 if ((rx_buf[5] >> 6) & 0x1) {
494                         /* Remote transmission request */
495                         frame->can_id |= CAN_RTR_FLAG;
496                 }
497
498                 /* Data length */
499                 frame->can_dlc = rx_buf[5] & 0x0f;
500                 if (frame->can_dlc > 8) {
501                         dev_warn(&spi->dev, "invalid frame recevied\n");
502                         priv->net->stats.rx_errors++;
503                         dev_kfree_skb(skb);
504                         mutex_unlock(&priv->spi_lock);
505                         return;
506                 }
507
508                 memcpy(frame->data, rx_buf + 6, CAN_FRAME_MAX_DATA_LEN);
509
510                 mutex_unlock(&priv->spi_lock);
511         }
512
513         priv->net->stats.rx_packets++;
514         priv->net->stats.rx_bytes += frame->can_dlc;
515
516         skb->protocol = __constant_htons(ETH_P_CAN);
517         skb->pkt_type = PACKET_BROADCAST;
518         skb->ip_summed = CHECKSUM_UNNECESSARY;
519         netif_rx(skb);
520 }
521
522 static void mcp251x_hw_sleep(struct spi_device *spi)
523 {
524         mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_SLEEP);
525 }
526
527 static void mcp251x_hw_wakeup(struct spi_device *spi)
528 {
529         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
530
531         priv->wake = 1;
532
533         /* Can only wake up by generating a wake-up interrupt. */
534         mcp251x_write_bits(spi, CANINTE, CANINTE_WAKIE, CANINTE_WAKIE);
535         mcp251x_write_bits(spi, CANINTF, CANINTF_WAKIF, CANINTF_WAKIF);
536
537         /* Wait until the device is awake */
538         wait_for_completion(&priv->awake);
539 }
540
541 static int mcp251x_hard_start_xmit(struct sk_buff *skb, struct net_device *net)
542 {
543         struct mcp251x_priv *priv = netdev_priv(net);
544         struct spi_device *spi = priv->spi;
545
546         dev_dbg(&spi->dev, "%s\n", __func__);
547
548         if (priv->tx_skb) {
549                 dev_warn(&spi->dev, "hard_xmit called with not null tx_skb\n");
550                 return NETDEV_TX_BUSY;
551         }
552
553         if (skb->len != sizeof(struct can_frame)) {
554                 dev_dbg(&spi->dev, "dropping packet - bad length\n");
555                 dev_kfree_skb(skb);
556                 net->stats.tx_dropped++;
557                 return 0;
558         }
559
560         netif_stop_queue(net);
561         priv->tx_skb = skb;
562         net->trans_start = jiffies;
563         queue_work(priv->wq, &priv->tx_work);
564
565         return NETDEV_TX_OK;
566 }
567
568 static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode)
569 {
570         struct mcp251x_priv *priv = netdev_priv(net);
571         struct spi_device *spi = priv->spi;
572
573         dev_dbg(&spi->dev, "%s (unimplemented)\n", __func__);
574
575         switch (mode) {
576         default:
577                 return -EOPNOTSUPP;
578         }
579
580         return 0;
581 }
582
583 static void mcp251x_set_normal_mode(struct spi_device *spi)
584 {
585         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
586
587         /* Enable interrupts */
588         mcp251x_write_reg(spi, CANINTE,
589                 CANINTE_ERRIE | CANINTE_TX2IE | CANINTE_TX1IE |
590                 CANINTE_TX0IE | CANINTE_RX1IE | CANINTE_RX0IE);
591
592         if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
593                 /* Put device into loopback mode */
594                 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LOOPBACK);
595         } else {
596                 /* Put device into normal mode */
597                 mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);
598
599                 /* Wait for the device to enter normal mode */
600                 while (mcp251x_read_reg(spi, CANSTAT) & 0xE0)
601                         udelay(10);
602         }
603 }
604
605 static void mcp251x_setup(struct net_device *net, struct mcp251x_priv *priv,
606                           struct spi_device *spi)
607 {
608         int ret;
609
610         /* Set initial baudrate */
611         ret = can_set_bittiming(net);
612         if (ret)
613                 dev_err(&spi->dev, "unable to set initial baudrate!\n");
614
615         /* Enable RX0->RX1 buffer roll over and disable filters */
616         mcp251x_write_bits(spi, RXBCTRL(0),
617                            RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1,
618                            RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1);
619         mcp251x_write_bits(spi, RXBCTRL(1),
620                            RXBCTRL_RXM0 | RXBCTRL_RXM1,
621                            RXBCTRL_RXM0 | RXBCTRL_RXM1);
622
623         dev_dbg(&spi->dev, "%s RXBCTL 0 and 1: %02x %02x\n", __func__,
624                 mcp251x_read_reg(spi, RXBCTRL(0)),
625                 mcp251x_read_reg(spi, RXBCTRL(1)));
626 }
627
628 static void mcp251x_hw_reset(struct spi_device *spi)
629 {
630         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
631         int ret;
632
633         mutex_lock(&priv->spi_lock);
634
635         priv->spi_tx_buf[0] = INSTRUCTION_RESET;
636
637         ret = spi_write(spi, priv->spi_tx_buf, 1);
638
639         mutex_unlock(&priv->spi_lock);
640
641         if (ret < 0)
642                 dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __func__, ret);
643 }
644
645 static int mcp251x_open(struct net_device *net)
646 {
647         struct mcp251x_priv *priv = netdev_priv(net);
648         struct spi_device *spi = priv->spi;
649         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
650
651         dev_dbg(&spi->dev, "%s\n", __func__);
652
653         if (pdata->transceiver_enable)
654                 pdata->transceiver_enable(1);
655
656         priv->force_quit = 0;
657         priv->tx_skb = NULL;
658         enable_irq(spi->irq);
659         mcp251x_hw_wakeup(spi);
660         mcp251x_hw_reset(spi);
661         mcp251x_setup(net, priv, spi);
662         mcp251x_set_normal_mode(spi);
663         netif_wake_queue(net);
664
665         return 0;
666 }
667
668 static int mcp251x_stop(struct net_device *net)
669 {
670         struct mcp251x_priv *priv = netdev_priv(net);
671         struct spi_device *spi = priv->spi;
672         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
673
674         dev_dbg(&spi->dev, "%s\n", __func__);
675
676         /* Disable and clear pending interrupts */
677         mcp251x_write_reg(spi, CANINTE, 0x00);
678         mcp251x_write_reg(spi, CANINTF, 0x00);
679
680         priv->force_quit = 1;
681         disable_irq(spi->irq);
682         flush_workqueue(priv->wq);
683
684         mcp251x_write_reg(spi, TXBCTRL(0), 0);
685         if (priv->tx_skb) {
686                 net->stats.tx_errors++;
687                 dev_kfree_skb(priv->tx_skb);
688                 priv->tx_skb = NULL;
689         }
690
691         mcp251x_hw_sleep(spi);
692
693         if (pdata->transceiver_enable)
694                 pdata->transceiver_enable(0);
695
696         return 0;
697 }
698
699 static int mcp251x_do_set_bittiming(struct net_device *net)
700 {
701         struct mcp251x_priv *priv = netdev_priv(net);
702         struct can_bittiming *bt = &priv->can.bittiming;
703         struct spi_device *spi = priv->spi;
704         u8 state;
705
706         dev_dbg(&spi->dev, "%s: BRP = %d, PropSeg = %d, PS1 = %d,"
707                 " PS2 = %d, SJW = %d\n", __func__, bt->brp,
708                 bt->prop_seg, bt->phase_seg1, bt->phase_seg2,
709                 bt->sjw);
710
711         /* Store original mode and set mode to config */
712         state = mcp251x_read_reg(spi, CANCTRL);
713         state = mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK;
714         mcp251x_write_bits(spi, CANCTRL, CANCTRL_REQOP_MASK,
715                            CANCTRL_REQOP_CONF);
716
717         mcp251x_write_reg(spi, CNF1, ((bt->sjw - 1) << 6) | (bt->brp - 1));
718         mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE |
719                           ((bt->phase_seg1 - 1) << 3) |
720                           (bt->prop_seg - 1));
721         mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK,
722                            (bt->phase_seg2 - 1));
723
724         /* Restore original state */
725         mcp251x_write_bits(spi, CANCTRL, CANCTRL_REQOP_MASK, state);
726
727         return 0;
728 }
729
730 static int mcp251x_do_get_state(struct net_device *net, enum can_state  *state)
731 {
732         struct mcp251x_priv *priv = netdev_priv(net);
733         struct spi_device *spi = priv->spi;
734         u8 eflag;
735
736         eflag = mcp251x_read_reg(spi, EFLG);
737
738         if (eflag & EFLG_TXBO)
739                 *state = CAN_STATE_BUS_OFF;
740         else if (eflag & (EFLG_RXEP | EFLG_TXEP))
741                 *state = CAN_STATE_BUS_PASSIVE;
742         else if (eflag & EFLG_EWARN)
743                 *state = CAN_STATE_BUS_WARNING;
744         else
745                 *state = CAN_STATE_ACTIVE;
746
747         return 0;
748 }
749
750 static void mcp251x_tx_work_handler(struct work_struct *ws)
751 {
752         struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
753                                                  tx_work);
754         struct spi_device *spi = priv->spi;
755         struct can_frame *frame = (struct can_frame *)priv->tx_skb->data;
756
757         dev_dbg(&spi->dev, "%s\n", __func__);
758
759         if (frame->can_dlc > CAN_FRAME_MAX_DATA_LEN)
760                 frame->can_dlc = CAN_FRAME_MAX_DATA_LEN;
761
762         mcp251x_hw_tx(spi, frame, 0);
763 }
764
765 static void mcp251x_irq_work_handler(struct work_struct *ws)
766 {
767         struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
768                                                  irq_work);
769         struct spi_device *spi = priv->spi;
770         struct net_device *net = priv->net;
771         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
772         u8 intf;
773         u8 txbnctrl;
774         /* the next limitation is needed so we give some time to the
775          * tx workqueue */
776 #define MAX_LOOPS 10
777         int loops;
778
779         if (priv->after_suspend) {
780                 /* Wait whilst the device wakes up */
781                 udelay(200 * (128 * USEC_PER_SEC /
782                               pdata->oscillator_frequency));
783                 mcp251x_hw_reset(spi);
784                 mcp251x_setup(net, priv, spi);
785                 if (priv->after_suspend & AFTER_SUSPEND_UP) {
786                         /* clear since we lost tx buffer */
787                         netif_device_attach(net);
788                         if (priv->tx_skb) {
789                                 net->stats.tx_errors++;
790                                 dev_kfree_skb(priv->tx_skb);
791                                 priv->tx_skb = NULL;
792                                 netif_wake_queue(net);
793                         }
794                         mcp251x_set_normal_mode(spi);
795                 } else
796                         mcp251x_hw_sleep(spi);
797                 priv->after_suspend = 0;
798                 return;
799         }
800
801         loops = 0;
802         while (!priv->force_quit && !freezing(current) && loops < MAX_LOOPS) {
803                 if (priv->restart_tx) {
804                         priv->restart_tx = 0;
805                         dev_warn(&spi->dev,
806                                  "timeout in txing a packet, restarting\n");
807                         mcp251x_write_reg(spi, TXBCTRL(0), 0);
808                         if (priv->tx_skb) {
809                                 net->stats.tx_errors++;
810                                 dev_kfree_skb(priv->tx_skb);
811                                 priv->tx_skb = NULL;
812                         }
813                         netif_wake_queue(net);
814                 }
815
816                 if (priv->wake) {
817                         /* Wait whilst the device wakes up */
818                         udelay(200 * (128 * USEC_PER_SEC /
819                                       pdata->oscillator_frequency));
820                         priv->wake = 0;
821                 }
822
823                 intf = mcp251x_read_reg(spi, CANINTF);
824                 if (intf == 0x00)
825                         break;
826                 mcp251x_write_bits(spi, CANINTF, intf, 0x00);
827
828                 dev_dbg(&spi->dev, "interrupt:%s%s%s%s%s%s%s%s\n",
829                         (intf & CANINTF_MERRF) ? " MERR" : "",
830                         (intf & CANINTF_WAKIF) ? " WAK" : "",
831                         (intf & CANINTF_ERRIF) ? " ERR" : "",
832                         (intf & CANINTF_TX2IF) ? " TX2" : "",
833                         (intf & CANINTF_TX1IF) ? " TX1" : "",
834                         (intf & CANINTF_TX0IF) ? " TX0" : "",
835                         (intf & CANINTF_RX1IF) ? " RX1" : "",
836                         (intf & CANINTF_RX0IF) ? " RX0" : "");
837
838                 if (intf & CANINTF_WAKIF)
839                         complete(&priv->awake);
840
841                 if (intf & CANINTF_MERRF) {
842                         /* if there are no pending Tx buffers, restart queue */
843                         txbnctrl = mcp251x_read_reg(spi, TXBCTRL(0));
844                         if (!(txbnctrl & TXBCTRL_TXREQ)) {
845                                 if (priv->tx_skb) {
846                                         net->stats.tx_errors++;
847                                         dev_kfree_skb(priv->tx_skb);
848                                         priv->tx_skb = NULL;
849                                 }
850                                 netif_wake_queue(net);
851                         }
852                 }
853
854                 if (intf & CANINTF_ERRIF) {
855                         struct sk_buff *skb;
856                         struct can_frame *frame = NULL;
857                         u8 eflag = mcp251x_read_reg(spi, EFLG);
858
859                         dev_dbg(&spi->dev, "EFLG = 0x%02x\n", eflag);
860
861                         /* Create error frame */
862                         skb = dev_alloc_skb(sizeof(struct can_frame));
863                         if (skb) {
864                                 frame = (struct can_frame *)
865                                         skb_put(skb, sizeof(struct can_frame));
866                                 frame->can_id = CAN_ERR_FLAG;
867                                 frame->can_dlc = CAN_ERR_DLC;
868
869                                 skb->dev = net;
870                                 skb->protocol = __constant_htons(ETH_P_CAN);
871                                 skb->pkt_type = PACKET_BROADCAST;
872                                 skb->ip_summed = CHECKSUM_UNNECESSARY;
873
874                                 /* Set error frame flags based on bus state */
875                                 if (eflag & EFLG_TXBO) {
876                                         frame->can_id |= CAN_ERR_BUSOFF;
877                                 } else if (eflag & EFLG_TXEP) {
878                                         frame->can_id |= CAN_ERR_CRTL;
879                                         frame->data[1] |=
880                                           CAN_ERR_CRTL_TX_PASSIVE;
881                                 } else if (eflag & EFLG_RXEP) {
882                                         frame->can_id |= CAN_ERR_CRTL;
883                                         frame->data[1] |=
884                                           CAN_ERR_CRTL_RX_PASSIVE;
885                                 } else if (eflag & EFLG_TXWAR) {
886                                         frame->can_id |= CAN_ERR_CRTL;
887                                         frame->data[1] |=
888                                           CAN_ERR_CRTL_TX_WARNING;
889                                 } else if (eflag & EFLG_RXWAR) {
890                                         frame->can_id |= CAN_ERR_CRTL;
891                                         frame->data[1] |=
892                                           CAN_ERR_CRTL_RX_WARNING;
893                                 }
894                         }
895
896                         if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) {
897                                 if (eflag & EFLG_RX0OVR)
898                                         net->stats.rx_over_errors++;
899                                 if (eflag & EFLG_RX1OVR)
900                                         net->stats.rx_over_errors++;
901                                 if (frame) {
902                                         frame->can_id |= CAN_ERR_CRTL;
903                                         frame->data[1] =
904                                           CAN_ERR_CRTL_RX_OVERFLOW;
905                                 }
906                         }
907                         mcp251x_write_reg(spi, EFLG, 0x00);
908
909                         if (skb)
910                                 netif_rx(skb);
911                 }
912
913                 if (intf & (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)) {
914                         if (priv->tx_skb) {
915                                 net->stats.tx_packets++;
916                                 net->stats.tx_bytes +=
917                                         ((struct can_frame *)
918                                          (priv->tx_skb->data))->can_dlc;
919                                 dev_kfree_skb(priv->tx_skb);
920                                 priv->tx_skb = NULL;
921                         }
922                         netif_wake_queue(net);
923                 }
924
925                 if (intf & CANINTF_RX0IF)
926                         mcp251x_hw_rx(spi, 0);
927
928                 if (intf & CANINTF_RX1IF)
929                         mcp251x_hw_rx(spi, 1);
930
931                 loops++;
932         }
933
934         mcp251x_read_reg(spi, CANSTAT);
935
936         dev_dbg(&spi->dev, "interrupt ended\n");
937 }
938
939 static irqreturn_t mcp251x_can_isr(int irq, void *dev_id)
940 {
941         struct net_device *net = (struct net_device *)dev_id;
942         struct mcp251x_priv *priv = netdev_priv(net);
943
944         dev_dbg(&priv->spi->dev, "%s: irq\n", __func__);
945         /* Schedule bottom half */
946         if (!work_pending(&priv->irq_work))
947                 queue_work(priv->wq, &priv->irq_work);
948
949         return IRQ_HANDLED;
950 }
951
952 static void mcp251x_tx_timeout(struct net_device *net)
953 {
954         struct mcp251x_priv *priv = netdev_priv(net);
955
956         priv->restart_tx = 1;
957         queue_work(priv->wq, &priv->irq_work);
958 }
959
960 static struct net_device *alloc_mcp251x_netdev(int sizeof_priv)
961 {
962         struct net_device *net;
963         struct mcp251x_priv *priv;
964
965         net = alloc_candev(sizeof_priv);
966         if (!net)
967                 return NULL;
968
969         priv = netdev_priv(net);
970
971         net->open               = mcp251x_open;
972         net->stop               = mcp251x_stop;
973         net->hard_start_xmit    = mcp251x_hard_start_xmit;
974         net->tx_timeout         = mcp251x_tx_timeout;
975         net->watchdog_timeo     = HZ;
976
977         priv->can.bittiming_const = &mcp251x_bittiming_const;
978         priv->can.do_set_bittiming = mcp251x_do_set_bittiming;
979         priv->can.do_get_state    = mcp251x_do_get_state;
980         priv->can.do_set_mode     = mcp251x_do_set_mode;
981
982         priv->net = net;
983
984         return net;
985 }
986
987 static int __devinit mcp251x_can_probe(struct spi_device *spi)
988 {
989         struct net_device *net;
990         struct mcp251x_priv *priv;
991         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
992         int ret = -ENODEV;
993
994         if (!pdata) {
995                 /* Platform data is required for osc freq */
996                 goto error_out;
997         }
998
999         /* Allocate can/net device */
1000         net = alloc_mcp251x_netdev(sizeof(struct mcp251x_priv));
1001         if (!net) {
1002                 ret = -ENOMEM;
1003                 goto error_alloc;
1004         }
1005
1006         priv = netdev_priv(net);
1007         dev_set_drvdata(&spi->dev, priv);
1008
1009         priv->spi = spi;
1010         mutex_init(&priv->spi_lock);
1011
1012         priv->can.bittiming.clock = pdata->oscillator_frequency / 2;
1013
1014         /* If requested, allocate DMA buffers */
1015         if (enable_dma) {
1016                 spi->dev.coherent_dma_mask = DMA_32BIT_MASK;
1017
1018                 /* Minimum coherent DMA allocation is PAGE_SIZE, so allocate
1019                    that much and share it between Tx and Rx DMA buffers. */
1020                 priv->spi_tx_buf = dma_alloc_coherent(&spi->dev,
1021                         PAGE_SIZE, &priv->spi_tx_dma, GFP_DMA);
1022
1023                 if (priv->spi_tx_buf) {
1024                         priv->spi_rx_buf = (u8 *)(priv->spi_tx_buf +
1025                                 (PAGE_SIZE / 2));
1026                         priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
1027                                 (PAGE_SIZE / 2));
1028                 } else {
1029                         /* Fall back to non-DMA */
1030                         enable_dma = 0;
1031                 }
1032         }
1033
1034         /* Allocate non-DMA buffers */
1035         if (!enable_dma) {
1036                 priv->spi_tx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
1037                 if (!priv->spi_tx_buf) {
1038                         ret = -ENOMEM;
1039                         goto error_tx_buf;
1040                 }
1041                 priv->spi_rx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
1042                 if (!priv->spi_tx_buf) {
1043                         ret = -ENOMEM;
1044                         goto error_rx_buf;
1045                 }
1046         }
1047
1048         if (pdata->power_enable)
1049                 pdata->power_enable(1);
1050
1051         /* Call out to platform specific setup */
1052         if (pdata->board_specific_setup)
1053                 pdata->board_specific_setup(spi);
1054
1055         SET_NETDEV_DEV(net, &spi->dev);
1056
1057         priv->wq = create_freezeable_workqueue("mcp251x_wq");
1058
1059         INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
1060         INIT_WORK(&priv->irq_work, mcp251x_irq_work_handler);
1061
1062         init_completion(&priv->awake);
1063
1064         /* Configure the SPI bus */
1065         spi->mode = SPI_MODE_0;
1066         spi->bits_per_word = 8;
1067         spi_setup(spi);
1068
1069         /* Register IRQ */
1070         if (request_irq(spi->irq, mcp251x_can_isr,
1071                         IRQF_TRIGGER_FALLING, DEVICE_NAME, net) < 0) {
1072                 dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
1073                 goto error_irq;
1074         }
1075         disable_irq(spi->irq);
1076
1077         mcp251x_hw_reset(spi);
1078         mcp251x_hw_sleep(spi);
1079
1080         ret = register_netdev(net);
1081         if (ret >= 0) {
1082                 dev_info(&spi->dev, "probed\n");
1083                 return ret;
1084         }
1085
1086         free_irq(spi->irq, net);
1087 error_irq:
1088         if (!enable_dma)
1089                 kfree(priv->spi_rx_buf);
1090 error_rx_buf:
1091         if (!enable_dma)
1092                 kfree(priv->spi_tx_buf);
1093 error_tx_buf:
1094         free_candev(net);
1095         if (enable_dma) {
1096                 dma_free_coherent(&spi->dev, PAGE_SIZE,
1097                         priv->spi_tx_buf, priv->spi_tx_dma);
1098         }
1099 error_alloc:
1100         dev_err(&spi->dev, "probe failed\n");
1101 error_out:
1102         return ret;
1103 }
1104
1105 static int __devexit mcp251x_can_remove(struct spi_device *spi)
1106 {
1107         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1108         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
1109         struct net_device *net = priv->net;
1110
1111         free_irq(spi->irq, net);
1112         priv->force_quit = 1;
1113         flush_workqueue(priv->wq);
1114         destroy_workqueue(priv->wq);
1115
1116         if (enable_dma) {
1117                 dma_free_coherent(&spi->dev, PAGE_SIZE,
1118                         priv->spi_tx_buf, priv->spi_tx_dma);
1119         } else {
1120                 kfree(priv->spi_tx_buf);
1121                 kfree(priv->spi_rx_buf);
1122         }
1123
1124         unregister_netdev(net);
1125         free_candev(net);
1126
1127         if (pdata->power_enable)
1128                 pdata->power_enable(0);
1129
1130         return 0;
1131 }
1132
1133 #ifdef CONFIG_PM
1134 static int mcp251x_can_suspend(struct spi_device *spi, pm_message_t state)
1135 {
1136         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1137         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
1138         struct net_device *net = priv->net;
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         if (pdata->power_enable) {
1151                 pdata->power_enable(0);
1152                 priv->after_suspend |= AFTER_SUSPEND_POWER;
1153         }
1154
1155         return 0;
1156 }
1157
1158 static int mcp251x_can_resume(struct spi_device *spi)
1159 {
1160         struct mcp251x_platform_data *pdata = spi->dev.platform_data;
1161         struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev);
1162         struct net_device *net = priv->net;
1163
1164         if (priv->after_suspend & AFTER_SUSPEND_POWER) {
1165                 pdata->power_enable(1);
1166                 queue_work(priv->wq, &priv->irq_work);
1167         } else {
1168                 if (priv->after_suspend & AFTER_SUSPEND_UP) {
1169                         if (pdata->transceiver_enable)
1170                                 pdata->transceiver_enable(1);
1171                         mcp251x_hw_wakeup(spi);
1172
1173                         netif_device_attach(net);
1174                 }
1175         }
1176         return 0;
1177 }
1178 #else
1179 #define mcp251x_can_suspend NULL
1180 #define mcp251x_can_resume NULL
1181 #endif
1182
1183 static struct spi_driver mcp251x_can_driver = {
1184         .driver = {
1185                 .name           = DEVICE_NAME,
1186                 .bus            = &spi_bus_type,
1187                 .owner          = THIS_MODULE,
1188         },
1189
1190         .probe          = mcp251x_can_probe,
1191         .remove         = __devexit_p(mcp251x_can_remove),
1192         .suspend        = mcp251x_can_suspend,
1193         .resume         = mcp251x_can_resume,
1194 };
1195
1196 static int __init mcp251x_can_init(void)
1197 {
1198         return spi_register_driver(&mcp251x_can_driver);
1199 }
1200
1201 static void __exit mcp251x_can_exit(void)
1202 {
1203         spi_unregister_driver(&mcp251x_can_driver);
1204 }
1205
1206 module_init(mcp251x_can_init);
1207 module_exit(mcp251x_can_exit);
1208
1209 MODULE_AUTHOR("Chris Elston <celston@katalix.com>, "
1210               "Christian Pellegrin <chripell@evolware.org>");
1211 MODULE_DESCRIPTION("Microchip 251x CAN driver");
1212 MODULE_LICENSE("GPL v2");