1 /* Renesas R-Car CAN device driver
2 *
3 * Copyright (C) 2013 Cogent Embedded, Inc. <source@cogentembedded.com>
4 * Copyright (C) 2013 Renesas Solutions Corp.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/types.h>
15 #include <linux/interrupt.h>
16 #include <linux/errno.h>
17 #include <linux/netdevice.h>
18 #include <linux/platform_device.h>
19 #include <linux/can/led.h>
20 #include <linux/can/dev.h>
21 #include <linux/clk.h>
22 #include <linux/can/platform/rcar_can.h>
23 #include <linux/of.h>
24
25 #define RCAR_CAN_DRV_NAME "rcar_can"
26
27 /* Mailbox configuration:
28 * mailbox 60 - 63 - Rx FIFO mailboxes
29 * mailbox 56 - 59 - Tx FIFO mailboxes
30 * non-FIFO mailboxes are not used
31 */
32 #define RCAR_CAN_N_MBX 64 /* Number of mailboxes in non-FIFO mode */
33 #define RCAR_CAN_RX_FIFO_MBX 60 /* Mailbox - window to Rx FIFO */
34 #define RCAR_CAN_TX_FIFO_MBX 56 /* Mailbox - window to Tx FIFO */
35 #define RCAR_CAN_FIFO_DEPTH 4
36
37 /* Mailbox registers structure */
38 struct rcar_can_mbox_regs {
39 u32 id; /* IDE and RTR bits, SID and EID */
40 u8 stub; /* Not used */
41 u8 dlc; /* Data Length Code - bits [0..3] */
42 u8 data[8]; /* Data Bytes */
43 u8 tsh; /* Time Stamp Higher Byte */
44 u8 tsl; /* Time Stamp Lower Byte */
45 };
46
47 struct rcar_can_regs {
48 struct rcar_can_mbox_regs mb[RCAR_CAN_N_MBX]; /* Mailbox registers */
49 u32 mkr_2_9[8]; /* Mask Registers 2-9 */
50 u32 fidcr[2]; /* FIFO Received ID Compare Register */
51 u32 mkivlr1; /* Mask Invalid Register 1 */
52 u32 mier1; /* Mailbox Interrupt Enable Register 1 */
53 u32 mkr_0_1[2]; /* Mask Registers 0-1 */
54 u32 mkivlr0; /* Mask Invalid Register 0*/
55 u32 mier0; /* Mailbox Interrupt Enable Register 0 */
56 u8 pad_440[0x3c0];
57 u8 mctl[64]; /* Message Control Registers */
58 u16 ctlr; /* Control Register */
59 u16 str; /* Status register */
60 u8 bcr[3]; /* Bit Configuration Register */
61 u8 clkr; /* Clock Select Register */
62 u8 rfcr; /* Receive FIFO Control Register */
63 u8 rfpcr; /* Receive FIFO Pointer Control Register */
64 u8 tfcr; /* Transmit FIFO Control Register */
65 u8 tfpcr; /* Transmit FIFO Pointer Control Register */
66 u8 eier; /* Error Interrupt Enable Register */
67 u8 eifr; /* Error Interrupt Factor Judge Register */
68 u8 recr; /* Receive Error Count Register */
69 u8 tecr; /* Transmit Error Count Register */
70 u8 ecsr; /* Error Code Store Register */
71 u8 cssr; /* Channel Search Support Register */
72 u8 mssr; /* Mailbox Search Status Register */
73 u8 msmr; /* Mailbox Search Mode Register */
74 u16 tsr; /* Time Stamp Register */
75 u8 afsr; /* Acceptance Filter Support Register */
76 u8 pad_857;
77 u8 tcr; /* Test Control Register */
78 u8 pad_859[7];
79 u8 ier; /* Interrupt Enable Register */
80 u8 isr; /* Interrupt Status Register */
81 u8 pad_862;
82 u8 mbsmr; /* Mailbox Search Mask Register */
83 };
84
85 struct rcar_can_priv {
86 struct can_priv can; /* Must be the first member! */
87 struct net_device *ndev;
88 struct napi_struct napi;
89 struct rcar_can_regs __iomem *regs;
90 struct clk *clk;
91 struct clk *can_clk;
92 u8 tx_dlc[RCAR_CAN_FIFO_DEPTH];
93 u32 tx_head;
94 u32 tx_tail;
95 u8 clock_select;
96 u8 ier;
97 };
98
99 static const struct can_bittiming_const rcar_can_bittiming_const = {
100 .name = RCAR_CAN_DRV_NAME,
101 .tseg1_min = 4,
102 .tseg1_max = 16,
103 .tseg2_min = 2,
104 .tseg2_max = 8,
105 .sjw_max = 4,
106 .brp_min = 1,
107 .brp_max = 1024,
108 .brp_inc = 1,
109 };
110
111 /* Control Register bits */
112 #define RCAR_CAN_CTLR_BOM (3 << 11) /* Bus-Off Recovery Mode Bits */
113 #define RCAR_CAN_CTLR_BOM_ENT (1 << 11) /* Entry to halt mode */
114 /* at bus-off entry */
115 #define RCAR_CAN_CTLR_SLPM (1 << 10)
116 #define RCAR_CAN_CTLR_CANM (3 << 8) /* Operating Mode Select Bit */
117 #define RCAR_CAN_CTLR_CANM_HALT (1 << 9)
118 #define RCAR_CAN_CTLR_CANM_RESET (1 << 8)
119 #define RCAR_CAN_CTLR_CANM_FORCE_RESET (3 << 8)
120 #define RCAR_CAN_CTLR_MLM (1 << 3) /* Message Lost Mode Select */
121 #define RCAR_CAN_CTLR_IDFM (3 << 1) /* ID Format Mode Select Bits */
122 #define RCAR_CAN_CTLR_IDFM_MIXED (1 << 2) /* Mixed ID mode */
123 #define RCAR_CAN_CTLR_MBM (1 << 0) /* Mailbox Mode select */
124
125 /* Status Register bits */
126 #define RCAR_CAN_STR_RSTST (1 << 8) /* Reset Status Bit */
127
128 /* FIFO Received ID Compare Registers 0 and 1 bits */
129 #define RCAR_CAN_FIDCR_IDE (1 << 31) /* ID Extension Bit */
130 #define RCAR_CAN_FIDCR_RTR (1 << 30) /* Remote Transmission Request Bit */
131
132 /* Receive FIFO Control Register bits */
133 #define RCAR_CAN_RFCR_RFEST (1 << 7) /* Receive FIFO Empty Status Flag */
134 #define RCAR_CAN_RFCR_RFE (1 << 0) /* Receive FIFO Enable */
135
136 /* Transmit FIFO Control Register bits */
137 #define RCAR_CAN_TFCR_TFUST (7 << 1) /* Transmit FIFO Unsent Message */
138 /* Number Status Bits */
139 #define RCAR_CAN_TFCR_TFUST_SHIFT 1 /* Offset of Transmit FIFO Unsent */
140 /* Message Number Status Bits */
141 #define RCAR_CAN_TFCR_TFE (1 << 0) /* Transmit FIFO Enable */
142
143 #define RCAR_CAN_N_RX_MKREGS1 2 /* Number of mask registers */
144 /* for Rx mailboxes 0-31 */
145 #define RCAR_CAN_N_RX_MKREGS2 8
146
147 /* Bit Configuration Register settings */
148 #define RCAR_CAN_BCR_TSEG1(x) (((x) & 0x0f) << 20)
149 #define RCAR_CAN_BCR_BPR(x) (((x) & 0x3ff) << 8)
150 #define RCAR_CAN_BCR_SJW(x) (((x) & 0x3) << 4)
151 #define RCAR_CAN_BCR_TSEG2(x) ((x) & 0x07)
152
153 /* Mailbox and Mask Registers bits */
154 #define RCAR_CAN_IDE (1 << 31)
155 #define RCAR_CAN_RTR (1 << 30)
156 #define RCAR_CAN_SID_SHIFT 18
157
158 /* Mailbox Interrupt Enable Register 1 bits */
159 #define RCAR_CAN_MIER1_RXFIE (1 << 28) /* Receive FIFO Interrupt Enable */
160 #define RCAR_CAN_MIER1_TXFIE (1 << 24) /* Transmit FIFO Interrupt Enable */
161
162 /* Interrupt Enable Register bits */
163 #define RCAR_CAN_IER_ERSIE (1 << 5) /* Error (ERS) Interrupt Enable Bit */
164 #define RCAR_CAN_IER_RXFIE (1 << 4) /* Reception FIFO Interrupt */
165 /* Enable Bit */
166 #define RCAR_CAN_IER_TXFIE (1 << 3) /* Transmission FIFO Interrupt */
167 /* Enable Bit */
168 /* Interrupt Status Register bits */
169 #define RCAR_CAN_ISR_ERSF (1 << 5) /* Error (ERS) Interrupt Status Bit */
170 #define RCAR_CAN_ISR_RXFF (1 << 4) /* Reception FIFO Interrupt */
171 /* Status Bit */
172 #define RCAR_CAN_ISR_TXFF (1 << 3) /* Transmission FIFO Interrupt */
173 /* Status Bit */
174
175 /* Error Interrupt Enable Register bits */
176 #define RCAR_CAN_EIER_BLIE (1 << 7) /* Bus Lock Interrupt Enable */
177 #define RCAR_CAN_EIER_OLIE (1 << 6) /* Overload Frame Transmit */
178 /* Interrupt Enable */
179 #define RCAR_CAN_EIER_ORIE (1 << 5) /* Receive Overrun Interrupt Enable */
180 #define RCAR_CAN_EIER_BORIE (1 << 4) /* Bus-Off Recovery Interrupt Enable */
181 #define RCAR_CAN_EIER_BOEIE (1 << 3) /* Bus-Off Entry Interrupt Enable */
182 #define RCAR_CAN_EIER_EPIE (1 << 2) /* Error Passive Interrupt Enable */
183 #define RCAR_CAN_EIER_EWIE (1 << 1) /* Error Warning Interrupt Enable */
184 #define RCAR_CAN_EIER_BEIE (1 << 0) /* Bus Error Interrupt Enable */
185
186 /* Error Interrupt Factor Judge Register bits */
187 #define RCAR_CAN_EIFR_BLIF (1 << 7) /* Bus Lock Detect Flag */
188 #define RCAR_CAN_EIFR_OLIF (1 << 6) /* Overload Frame Transmission */
189 /* Detect Flag */
190 #define RCAR_CAN_EIFR_ORIF (1 << 5) /* Receive Overrun Detect Flag */
191 #define RCAR_CAN_EIFR_BORIF (1 << 4) /* Bus-Off Recovery Detect Flag */
192 #define RCAR_CAN_EIFR_BOEIF (1 << 3) /* Bus-Off Entry Detect Flag */
193 #define RCAR_CAN_EIFR_EPIF (1 << 2) /* Error Passive Detect Flag */
194 #define RCAR_CAN_EIFR_EWIF (1 << 1) /* Error Warning Detect Flag */
195 #define RCAR_CAN_EIFR_BEIF (1 << 0) /* Bus Error Detect Flag */
196
197 /* Error Code Store Register bits */
198 #define RCAR_CAN_ECSR_EDPM (1 << 7) /* Error Display Mode Select Bit */
199 #define RCAR_CAN_ECSR_ADEF (1 << 6) /* ACK Delimiter Error Flag */
200 #define RCAR_CAN_ECSR_BE0F (1 << 5) /* Bit Error (dominant) Flag */
201 #define RCAR_CAN_ECSR_BE1F (1 << 4) /* Bit Error (recessive) Flag */
202 #define RCAR_CAN_ECSR_CEF (1 << 3) /* CRC Error Flag */
203 #define RCAR_CAN_ECSR_AEF (1 << 2) /* ACK Error Flag */
204 #define RCAR_CAN_ECSR_FEF (1 << 1) /* Form Error Flag */
205 #define RCAR_CAN_ECSR_SEF (1 << 0) /* Stuff Error Flag */
206
207 #define RCAR_CAN_NAPI_WEIGHT 4
208 #define MAX_STR_READS 0x100
209
tx_failure_cleanup(struct net_device * ndev)210 static void tx_failure_cleanup(struct net_device *ndev)
211 {
212 int i;
213
214 for (i = 0; i < RCAR_CAN_FIFO_DEPTH; i++)
215 can_free_echo_skb(ndev, i);
216 }
217
rcar_can_error(struct net_device * ndev)218 static void rcar_can_error(struct net_device *ndev)
219 {
220 struct rcar_can_priv *priv = netdev_priv(ndev);
221 struct net_device_stats *stats = &ndev->stats;
222 struct can_frame *cf;
223 struct sk_buff *skb;
224 u8 eifr, txerr = 0, rxerr = 0;
225
226 /* Propagate the error condition to the CAN stack */
227 skb = alloc_can_err_skb(ndev, &cf);
228
229 eifr = readb(&priv->regs->eifr);
230 if (eifr & (RCAR_CAN_EIFR_EWIF | RCAR_CAN_EIFR_EPIF)) {
231 txerr = readb(&priv->regs->tecr);
232 rxerr = readb(&priv->regs->recr);
233 if (skb) {
234 cf->can_id |= CAN_ERR_CRTL;
235 cf->data[6] = txerr;
236 cf->data[7] = rxerr;
237 }
238 }
239 if (eifr & RCAR_CAN_EIFR_BEIF) {
240 int rx_errors = 0, tx_errors = 0;
241 u8 ecsr;
242
243 netdev_dbg(priv->ndev, "Bus error interrupt:\n");
244 if (skb) {
245 cf->can_id |= CAN_ERR_BUSERROR | CAN_ERR_PROT;
246 cf->data[2] = CAN_ERR_PROT_UNSPEC;
247 }
248 ecsr = readb(&priv->regs->ecsr);
249 if (ecsr & RCAR_CAN_ECSR_ADEF) {
250 netdev_dbg(priv->ndev, "ACK Delimiter Error\n");
251 tx_errors++;
252 writeb(~RCAR_CAN_ECSR_ADEF, &priv->regs->ecsr);
253 if (skb)
254 cf->data[3] |= CAN_ERR_PROT_LOC_ACK_DEL;
255 }
256 if (ecsr & RCAR_CAN_ECSR_BE0F) {
257 netdev_dbg(priv->ndev, "Bit Error (dominant)\n");
258 tx_errors++;
259 writeb(~RCAR_CAN_ECSR_BE0F, &priv->regs->ecsr);
260 if (skb)
261 cf->data[2] |= CAN_ERR_PROT_BIT0;
262 }
263 if (ecsr & RCAR_CAN_ECSR_BE1F) {
264 netdev_dbg(priv->ndev, "Bit Error (recessive)\n");
265 tx_errors++;
266 writeb(~RCAR_CAN_ECSR_BE1F, &priv->regs->ecsr);
267 if (skb)
268 cf->data[2] |= CAN_ERR_PROT_BIT1;
269 }
270 if (ecsr & RCAR_CAN_ECSR_CEF) {
271 netdev_dbg(priv->ndev, "CRC Error\n");
272 rx_errors++;
273 writeb(~RCAR_CAN_ECSR_CEF, &priv->regs->ecsr);
274 if (skb)
275 cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
276 }
277 if (ecsr & RCAR_CAN_ECSR_AEF) {
278 netdev_dbg(priv->ndev, "ACK Error\n");
279 tx_errors++;
280 writeb(~RCAR_CAN_ECSR_AEF, &priv->regs->ecsr);
281 if (skb) {
282 cf->can_id |= CAN_ERR_ACK;
283 cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
284 }
285 }
286 if (ecsr & RCAR_CAN_ECSR_FEF) {
287 netdev_dbg(priv->ndev, "Form Error\n");
288 rx_errors++;
289 writeb(~RCAR_CAN_ECSR_FEF, &priv->regs->ecsr);
290 if (skb)
291 cf->data[2] |= CAN_ERR_PROT_FORM;
292 }
293 if (ecsr & RCAR_CAN_ECSR_SEF) {
294 netdev_dbg(priv->ndev, "Stuff Error\n");
295 rx_errors++;
296 writeb(~RCAR_CAN_ECSR_SEF, &priv->regs->ecsr);
297 if (skb)
298 cf->data[2] |= CAN_ERR_PROT_STUFF;
299 }
300
301 priv->can.can_stats.bus_error++;
302 ndev->stats.rx_errors += rx_errors;
303 ndev->stats.tx_errors += tx_errors;
304 writeb(~RCAR_CAN_EIFR_BEIF, &priv->regs->eifr);
305 }
306 if (eifr & RCAR_CAN_EIFR_EWIF) {
307 netdev_dbg(priv->ndev, "Error warning interrupt\n");
308 priv->can.state = CAN_STATE_ERROR_WARNING;
309 priv->can.can_stats.error_warning++;
310 /* Clear interrupt condition */
311 writeb(~RCAR_CAN_EIFR_EWIF, &priv->regs->eifr);
312 if (skb)
313 cf->data[1] = txerr > rxerr ? CAN_ERR_CRTL_TX_WARNING :
314 CAN_ERR_CRTL_RX_WARNING;
315 }
316 if (eifr & RCAR_CAN_EIFR_EPIF) {
317 netdev_dbg(priv->ndev, "Error passive interrupt\n");
318 priv->can.state = CAN_STATE_ERROR_PASSIVE;
319 priv->can.can_stats.error_passive++;
320 /* Clear interrupt condition */
321 writeb(~RCAR_CAN_EIFR_EPIF, &priv->regs->eifr);
322 if (skb)
323 cf->data[1] = txerr > rxerr ? CAN_ERR_CRTL_TX_PASSIVE :
324 CAN_ERR_CRTL_RX_PASSIVE;
325 }
326 if (eifr & RCAR_CAN_EIFR_BOEIF) {
327 netdev_dbg(priv->ndev, "Bus-off entry interrupt\n");
328 tx_failure_cleanup(ndev);
329 priv->ier = RCAR_CAN_IER_ERSIE;
330 writeb(priv->ier, &priv->regs->ier);
331 priv->can.state = CAN_STATE_BUS_OFF;
332 /* Clear interrupt condition */
333 writeb(~RCAR_CAN_EIFR_BOEIF, &priv->regs->eifr);
334 can_bus_off(ndev);
335 if (skb)
336 cf->can_id |= CAN_ERR_BUSOFF;
337 }
338 if (eifr & RCAR_CAN_EIFR_ORIF) {
339 netdev_dbg(priv->ndev, "Receive overrun error interrupt\n");
340 ndev->stats.rx_over_errors++;
341 ndev->stats.rx_errors++;
342 writeb(~RCAR_CAN_EIFR_ORIF, &priv->regs->eifr);
343 if (skb) {
344 cf->can_id |= CAN_ERR_CRTL;
345 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
346 }
347 }
348 if (eifr & RCAR_CAN_EIFR_OLIF) {
349 netdev_dbg(priv->ndev,
350 "Overload Frame Transmission error interrupt\n");
351 ndev->stats.rx_over_errors++;
352 ndev->stats.rx_errors++;
353 writeb(~RCAR_CAN_EIFR_OLIF, &priv->regs->eifr);
354 if (skb) {
355 cf->can_id |= CAN_ERR_PROT;
356 cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
357 }
358 }
359
360 if (skb) {
361 stats->rx_packets++;
362 stats->rx_bytes += cf->can_dlc;
363 netif_rx(skb);
364 }
365 }
366
rcar_can_tx_done(struct net_device * ndev)367 static void rcar_can_tx_done(struct net_device *ndev)
368 {
369 struct rcar_can_priv *priv = netdev_priv(ndev);
370 struct net_device_stats *stats = &ndev->stats;
371 u8 isr;
372
373 while (1) {
374 u8 unsent = readb(&priv->regs->tfcr);
375
376 unsent = (unsent & RCAR_CAN_TFCR_TFUST) >>
377 RCAR_CAN_TFCR_TFUST_SHIFT;
378 if (priv->tx_head - priv->tx_tail <= unsent)
379 break;
380 stats->tx_packets++;
381 stats->tx_bytes += priv->tx_dlc[priv->tx_tail %
382 RCAR_CAN_FIFO_DEPTH];
383 priv->tx_dlc[priv->tx_tail % RCAR_CAN_FIFO_DEPTH] = 0;
384 can_get_echo_skb(ndev, priv->tx_tail % RCAR_CAN_FIFO_DEPTH);
385 priv->tx_tail++;
386 netif_wake_queue(ndev);
387 }
388 /* Clear interrupt */
389 isr = readb(&priv->regs->isr);
390 writeb(isr & ~RCAR_CAN_ISR_TXFF, &priv->regs->isr);
391 can_led_event(ndev, CAN_LED_EVENT_TX);
392 }
393
rcar_can_interrupt(int irq,void * dev_id)394 static irqreturn_t rcar_can_interrupt(int irq, void *dev_id)
395 {
396 struct net_device *ndev = dev_id;
397 struct rcar_can_priv *priv = netdev_priv(ndev);
398 u8 isr;
399
400 isr = readb(&priv->regs->isr);
401 if (!(isr & priv->ier))
402 return IRQ_NONE;
403
404 if (isr & RCAR_CAN_ISR_ERSF)
405 rcar_can_error(ndev);
406
407 if (isr & RCAR_CAN_ISR_TXFF)
408 rcar_can_tx_done(ndev);
409
410 if (isr & RCAR_CAN_ISR_RXFF) {
411 if (napi_schedule_prep(&priv->napi)) {
412 /* Disable Rx FIFO interrupts */
413 priv->ier &= ~RCAR_CAN_IER_RXFIE;
414 writeb(priv->ier, &priv->regs->ier);
415 __napi_schedule(&priv->napi);
416 }
417 }
418
419 return IRQ_HANDLED;
420 }
421
rcar_can_set_bittiming(struct net_device * dev)422 static void rcar_can_set_bittiming(struct net_device *dev)
423 {
424 struct rcar_can_priv *priv = netdev_priv(dev);
425 struct can_bittiming *bt = &priv->can.bittiming;
426 u32 bcr;
427
428 bcr = RCAR_CAN_BCR_TSEG1(bt->phase_seg1 + bt->prop_seg - 1) |
429 RCAR_CAN_BCR_BPR(bt->brp - 1) | RCAR_CAN_BCR_SJW(bt->sjw - 1) |
430 RCAR_CAN_BCR_TSEG2(bt->phase_seg2 - 1);
431 /* Don't overwrite CLKR with 32-bit BCR access; CLKR has 8-bit access.
432 * All the registers are big-endian but they get byte-swapped on 32-bit
433 * read/write (but not on 8-bit, contrary to the manuals)...
434 */
435 writel((bcr << 8) | priv->clock_select, &priv->regs->bcr);
436 }
437
rcar_can_start(struct net_device * ndev)438 static void rcar_can_start(struct net_device *ndev)
439 {
440 struct rcar_can_priv *priv = netdev_priv(ndev);
441 u16 ctlr;
442 int i;
443
444 /* Set controller to known mode:
445 * - FIFO mailbox mode
446 * - accept all messages
447 * - overrun mode
448 * CAN is in sleep mode after MCU hardware or software reset.
449 */
450 ctlr = readw(&priv->regs->ctlr);
451 ctlr &= ~RCAR_CAN_CTLR_SLPM;
452 writew(ctlr, &priv->regs->ctlr);
453 /* Go to reset mode */
454 ctlr |= RCAR_CAN_CTLR_CANM_FORCE_RESET;
455 writew(ctlr, &priv->regs->ctlr);
456 for (i = 0; i < MAX_STR_READS; i++) {
457 if (readw(&priv->regs->str) & RCAR_CAN_STR_RSTST)
458 break;
459 }
460 rcar_can_set_bittiming(ndev);
461 ctlr |= RCAR_CAN_CTLR_IDFM_MIXED; /* Select mixed ID mode */
462 ctlr |= RCAR_CAN_CTLR_BOM_ENT; /* Entry to halt mode automatically */
463 /* at bus-off */
464 ctlr |= RCAR_CAN_CTLR_MBM; /* Select FIFO mailbox mode */
465 ctlr |= RCAR_CAN_CTLR_MLM; /* Overrun mode */
466 writew(ctlr, &priv->regs->ctlr);
467
468 /* Accept all SID and EID */
469 writel(0, &priv->regs->mkr_2_9[6]);
470 writel(0, &priv->regs->mkr_2_9[7]);
471 /* In FIFO mailbox mode, write "0" to bits 24 to 31 */
472 writel(0, &priv->regs->mkivlr1);
473 /* Accept all frames */
474 writel(0, &priv->regs->fidcr[0]);
475 writel(RCAR_CAN_FIDCR_IDE | RCAR_CAN_FIDCR_RTR, &priv->regs->fidcr[1]);
476 /* Enable and configure FIFO mailbox interrupts */
477 writel(RCAR_CAN_MIER1_RXFIE | RCAR_CAN_MIER1_TXFIE, &priv->regs->mier1);
478
479 priv->ier = RCAR_CAN_IER_ERSIE | RCAR_CAN_IER_RXFIE |
480 RCAR_CAN_IER_TXFIE;
481 writeb(priv->ier, &priv->regs->ier);
482
483 /* Accumulate error codes */
484 writeb(RCAR_CAN_ECSR_EDPM, &priv->regs->ecsr);
485 /* Enable error interrupts */
486 writeb(RCAR_CAN_EIER_EWIE | RCAR_CAN_EIER_EPIE | RCAR_CAN_EIER_BOEIE |
487 (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING ?
488 RCAR_CAN_EIER_BEIE : 0) | RCAR_CAN_EIER_ORIE |
489 RCAR_CAN_EIER_OLIE, &priv->regs->eier);
490 priv->can.state = CAN_STATE_ERROR_ACTIVE;
491
492 /* Go to operation mode */
493 writew(ctlr & ~RCAR_CAN_CTLR_CANM, &priv->regs->ctlr);
494 for (i = 0; i < MAX_STR_READS; i++) {
495 if (!(readw(&priv->regs->str) & RCAR_CAN_STR_RSTST))
496 break;
497 }
498 /* Enable Rx and Tx FIFO */
499 writeb(RCAR_CAN_RFCR_RFE, &priv->regs->rfcr);
500 writeb(RCAR_CAN_TFCR_TFE, &priv->regs->tfcr);
501 }
502
rcar_can_open(struct net_device * ndev)503 static int rcar_can_open(struct net_device *ndev)
504 {
505 struct rcar_can_priv *priv = netdev_priv(ndev);
506 int err;
507
508 err = clk_prepare_enable(priv->clk);
509 if (err) {
510 netdev_err(ndev, "failed to enable periperal clock, error %d\n",
511 err);
512 goto out;
513 }
514 err = clk_prepare_enable(priv->can_clk);
515 if (err) {
516 netdev_err(ndev, "failed to enable CAN clock, error %d\n",
517 err);
518 goto out_clock;
519 }
520 err = open_candev(ndev);
521 if (err) {
522 netdev_err(ndev, "open_candev() failed, error %d\n", err);
523 goto out_can_clock;
524 }
525 napi_enable(&priv->napi);
526 err = request_irq(ndev->irq, rcar_can_interrupt, 0, ndev->name, ndev);
527 if (err) {
528 netdev_err(ndev, "error requesting interrupt %x\n", ndev->irq);
529 goto out_close;
530 }
531 can_led_event(ndev, CAN_LED_EVENT_OPEN);
532 rcar_can_start(ndev);
533 netif_start_queue(ndev);
534 return 0;
535 out_close:
536 napi_disable(&priv->napi);
537 close_candev(ndev);
538 out_can_clock:
539 clk_disable_unprepare(priv->can_clk);
540 out_clock:
541 clk_disable_unprepare(priv->clk);
542 out:
543 return err;
544 }
545
rcar_can_stop(struct net_device * ndev)546 static void rcar_can_stop(struct net_device *ndev)
547 {
548 struct rcar_can_priv *priv = netdev_priv(ndev);
549 u16 ctlr;
550 int i;
551
552 /* Go to (force) reset mode */
553 ctlr = readw(&priv->regs->ctlr);
554 ctlr |= RCAR_CAN_CTLR_CANM_FORCE_RESET;
555 writew(ctlr, &priv->regs->ctlr);
556 for (i = 0; i < MAX_STR_READS; i++) {
557 if (readw(&priv->regs->str) & RCAR_CAN_STR_RSTST)
558 break;
559 }
560 writel(0, &priv->regs->mier0);
561 writel(0, &priv->regs->mier1);
562 writeb(0, &priv->regs->ier);
563 writeb(0, &priv->regs->eier);
564 /* Go to sleep mode */
565 ctlr |= RCAR_CAN_CTLR_SLPM;
566 writew(ctlr, &priv->regs->ctlr);
567 priv->can.state = CAN_STATE_STOPPED;
568 }
569
rcar_can_close(struct net_device * ndev)570 static int rcar_can_close(struct net_device *ndev)
571 {
572 struct rcar_can_priv *priv = netdev_priv(ndev);
573
574 netif_stop_queue(ndev);
575 rcar_can_stop(ndev);
576 free_irq(ndev->irq, ndev);
577 napi_disable(&priv->napi);
578 clk_disable_unprepare(priv->can_clk);
579 clk_disable_unprepare(priv->clk);
580 close_candev(ndev);
581 can_led_event(ndev, CAN_LED_EVENT_STOP);
582 return 0;
583 }
584
rcar_can_start_xmit(struct sk_buff * skb,struct net_device * ndev)585 static netdev_tx_t rcar_can_start_xmit(struct sk_buff *skb,
586 struct net_device *ndev)
587 {
588 struct rcar_can_priv *priv = netdev_priv(ndev);
589 struct can_frame *cf = (struct can_frame *)skb->data;
590 u32 data, i;
591
592 if (can_dropped_invalid_skb(ndev, skb))
593 return NETDEV_TX_OK;
594
595 if (cf->can_id & CAN_EFF_FLAG) /* Extended frame format */
596 data = (cf->can_id & CAN_EFF_MASK) | RCAR_CAN_IDE;
597 else /* Standard frame format */
598 data = (cf->can_id & CAN_SFF_MASK) << RCAR_CAN_SID_SHIFT;
599
600 if (cf->can_id & CAN_RTR_FLAG) { /* Remote transmission request */
601 data |= RCAR_CAN_RTR;
602 } else {
603 for (i = 0; i < cf->can_dlc; i++)
604 writeb(cf->data[i],
605 &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].data[i]);
606 }
607
608 writel(data, &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].id);
609
610 writeb(cf->can_dlc, &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].dlc);
611
612 priv->tx_dlc[priv->tx_head % RCAR_CAN_FIFO_DEPTH] = cf->can_dlc;
613 can_put_echo_skb(skb, ndev, priv->tx_head % RCAR_CAN_FIFO_DEPTH);
614 priv->tx_head++;
615 /* Start Tx: write 0xff to the TFPCR register to increment
616 * the CPU-side pointer for the transmit FIFO to the next
617 * mailbox location
618 */
619 writeb(0xff, &priv->regs->tfpcr);
620 /* Stop the queue if we've filled all FIFO entries */
621 if (priv->tx_head - priv->tx_tail >= RCAR_CAN_FIFO_DEPTH)
622 netif_stop_queue(ndev);
623
624 return NETDEV_TX_OK;
625 }
626
627 static const struct net_device_ops rcar_can_netdev_ops = {
628 .ndo_open = rcar_can_open,
629 .ndo_stop = rcar_can_close,
630 .ndo_start_xmit = rcar_can_start_xmit,
631 .ndo_change_mtu = can_change_mtu,
632 };
633
rcar_can_rx_pkt(struct rcar_can_priv * priv)634 static void rcar_can_rx_pkt(struct rcar_can_priv *priv)
635 {
636 struct net_device_stats *stats = &priv->ndev->stats;
637 struct can_frame *cf;
638 struct sk_buff *skb;
639 u32 data;
640 u8 dlc;
641
642 skb = alloc_can_skb(priv->ndev, &cf);
643 if (!skb) {
644 stats->rx_dropped++;
645 return;
646 }
647
648 data = readl(&priv->regs->mb[RCAR_CAN_RX_FIFO_MBX].id);
649 if (data & RCAR_CAN_IDE)
650 cf->can_id = (data & CAN_EFF_MASK) | CAN_EFF_FLAG;
651 else
652 cf->can_id = (data >> RCAR_CAN_SID_SHIFT) & CAN_SFF_MASK;
653
654 dlc = readb(&priv->regs->mb[RCAR_CAN_RX_FIFO_MBX].dlc);
655 cf->can_dlc = get_can_dlc(dlc);
656 if (data & RCAR_CAN_RTR) {
657 cf->can_id |= CAN_RTR_FLAG;
658 } else {
659 for (dlc = 0; dlc < cf->can_dlc; dlc++)
660 cf->data[dlc] =
661 readb(&priv->regs->mb[RCAR_CAN_RX_FIFO_MBX].data[dlc]);
662 }
663
664 can_led_event(priv->ndev, CAN_LED_EVENT_RX);
665
666 stats->rx_bytes += cf->can_dlc;
667 stats->rx_packets++;
668 netif_receive_skb(skb);
669 }
670
rcar_can_rx_poll(struct napi_struct * napi,int quota)671 static int rcar_can_rx_poll(struct napi_struct *napi, int quota)
672 {
673 struct rcar_can_priv *priv = container_of(napi,
674 struct rcar_can_priv, napi);
675 int num_pkts;
676
677 for (num_pkts = 0; num_pkts < quota; num_pkts++) {
678 u8 rfcr, isr;
679
680 isr = readb(&priv->regs->isr);
681 /* Clear interrupt bit */
682 if (isr & RCAR_CAN_ISR_RXFF)
683 writeb(isr & ~RCAR_CAN_ISR_RXFF, &priv->regs->isr);
684 rfcr = readb(&priv->regs->rfcr);
685 if (rfcr & RCAR_CAN_RFCR_RFEST)
686 break;
687 rcar_can_rx_pkt(priv);
688 /* Write 0xff to the RFPCR register to increment
689 * the CPU-side pointer for the receive FIFO
690 * to the next mailbox location
691 */
692 writeb(0xff, &priv->regs->rfpcr);
693 }
694 /* All packets processed */
695 if (num_pkts < quota) {
696 napi_complete(napi);
697 priv->ier |= RCAR_CAN_IER_RXFIE;
698 writeb(priv->ier, &priv->regs->ier);
699 }
700 return num_pkts;
701 }
702
rcar_can_do_set_mode(struct net_device * ndev,enum can_mode mode)703 static int rcar_can_do_set_mode(struct net_device *ndev, enum can_mode mode)
704 {
705 switch (mode) {
706 case CAN_MODE_START:
707 rcar_can_start(ndev);
708 netif_wake_queue(ndev);
709 return 0;
710 default:
711 return -EOPNOTSUPP;
712 }
713 }
714
rcar_can_get_berr_counter(const struct net_device * dev,struct can_berr_counter * bec)715 static int rcar_can_get_berr_counter(const struct net_device *dev,
716 struct can_berr_counter *bec)
717 {
718 struct rcar_can_priv *priv = netdev_priv(dev);
719 int err;
720
721 err = clk_prepare_enable(priv->clk);
722 if (err)
723 return err;
724 bec->txerr = readb(&priv->regs->tecr);
725 bec->rxerr = readb(&priv->regs->recr);
726 clk_disable_unprepare(priv->clk);
727 return 0;
728 }
729
730 static const char * const clock_names[] = {
731 [CLKR_CLKP1] = "clkp1",
732 [CLKR_CLKP2] = "clkp2",
733 [CLKR_CLKEXT] = "can_clk",
734 };
735
rcar_can_probe(struct platform_device * pdev)736 static int rcar_can_probe(struct platform_device *pdev)
737 {
738 struct rcar_can_platform_data *pdata;
739 struct rcar_can_priv *priv;
740 struct net_device *ndev;
741 struct resource *mem;
742 void __iomem *addr;
743 u32 clock_select = CLKR_CLKP1;
744 int err = -ENODEV;
745 int irq;
746
747 if (pdev->dev.of_node) {
748 of_property_read_u32(pdev->dev.of_node,
749 "renesas,can-clock-select", &clock_select);
750 } else {
751 pdata = dev_get_platdata(&pdev->dev);
752 if (!pdata) {
753 dev_err(&pdev->dev, "No platform data provided!\n");
754 goto fail;
755 }
756 clock_select = pdata->clock_select;
757 }
758
759 irq = platform_get_irq(pdev, 0);
760 if (!irq) {
761 dev_err(&pdev->dev, "No IRQ resource\n");
762 goto fail;
763 }
764
765 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
766 addr = devm_ioremap_resource(&pdev->dev, mem);
767 if (IS_ERR(addr)) {
768 err = PTR_ERR(addr);
769 goto fail;
770 }
771
772 ndev = alloc_candev(sizeof(struct rcar_can_priv), RCAR_CAN_FIFO_DEPTH);
773 if (!ndev) {
774 dev_err(&pdev->dev, "alloc_candev() failed\n");
775 err = -ENOMEM;
776 goto fail;
777 }
778
779 priv = netdev_priv(ndev);
780
781 priv->clk = devm_clk_get(&pdev->dev, "clkp1");
782 if (IS_ERR(priv->clk)) {
783 err = PTR_ERR(priv->clk);
784 dev_err(&pdev->dev, "cannot get peripheral clock: %d\n", err);
785 goto fail_clk;
786 }
787
788 if (clock_select >= ARRAY_SIZE(clock_names)) {
789 err = -EINVAL;
790 dev_err(&pdev->dev, "invalid CAN clock selected\n");
791 goto fail_clk;
792 }
793 priv->can_clk = devm_clk_get(&pdev->dev, clock_names[clock_select]);
794 if (IS_ERR(priv->can_clk)) {
795 err = PTR_ERR(priv->can_clk);
796 dev_err(&pdev->dev, "cannot get CAN clock: %d\n", err);
797 goto fail_clk;
798 }
799
800 ndev->netdev_ops = &rcar_can_netdev_ops;
801 ndev->irq = irq;
802 ndev->flags |= IFF_ECHO;
803 priv->ndev = ndev;
804 priv->regs = addr;
805 priv->clock_select = clock_select;
806 priv->can.clock.freq = clk_get_rate(priv->can_clk);
807 priv->can.bittiming_const = &rcar_can_bittiming_const;
808 priv->can.do_set_mode = rcar_can_do_set_mode;
809 priv->can.do_get_berr_counter = rcar_can_get_berr_counter;
810 priv->can.ctrlmode_supported = CAN_CTRLMODE_BERR_REPORTING;
811 platform_set_drvdata(pdev, ndev);
812 SET_NETDEV_DEV(ndev, &pdev->dev);
813
814 netif_napi_add(ndev, &priv->napi, rcar_can_rx_poll,
815 RCAR_CAN_NAPI_WEIGHT);
816 err = register_candev(ndev);
817 if (err) {
818 dev_err(&pdev->dev, "register_candev() failed, error %d\n",
819 err);
820 goto fail_candev;
821 }
822
823 devm_can_led_init(ndev);
824
825 dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%u)\n",
826 priv->regs, ndev->irq);
827
828 return 0;
829 fail_candev:
830 netif_napi_del(&priv->napi);
831 fail_clk:
832 free_candev(ndev);
833 fail:
834 return err;
835 }
836
rcar_can_remove(struct platform_device * pdev)837 static int rcar_can_remove(struct platform_device *pdev)
838 {
839 struct net_device *ndev = platform_get_drvdata(pdev);
840 struct rcar_can_priv *priv = netdev_priv(ndev);
841
842 unregister_candev(ndev);
843 netif_napi_del(&priv->napi);
844 free_candev(ndev);
845 return 0;
846 }
847
rcar_can_suspend(struct device * dev)848 static int __maybe_unused rcar_can_suspend(struct device *dev)
849 {
850 struct net_device *ndev = dev_get_drvdata(dev);
851 struct rcar_can_priv *priv = netdev_priv(ndev);
852 u16 ctlr;
853
854 if (netif_running(ndev)) {
855 netif_stop_queue(ndev);
856 netif_device_detach(ndev);
857 }
858 ctlr = readw(&priv->regs->ctlr);
859 ctlr |= RCAR_CAN_CTLR_CANM_HALT;
860 writew(ctlr, &priv->regs->ctlr);
861 ctlr |= RCAR_CAN_CTLR_SLPM;
862 writew(ctlr, &priv->regs->ctlr);
863 priv->can.state = CAN_STATE_SLEEPING;
864
865 clk_disable(priv->clk);
866 return 0;
867 }
868
rcar_can_resume(struct device * dev)869 static int __maybe_unused rcar_can_resume(struct device *dev)
870 {
871 struct net_device *ndev = dev_get_drvdata(dev);
872 struct rcar_can_priv *priv = netdev_priv(ndev);
873 u16 ctlr;
874 int err;
875
876 err = clk_enable(priv->clk);
877 if (err) {
878 netdev_err(ndev, "clk_enable() failed, error %d\n", err);
879 return err;
880 }
881
882 ctlr = readw(&priv->regs->ctlr);
883 ctlr &= ~RCAR_CAN_CTLR_SLPM;
884 writew(ctlr, &priv->regs->ctlr);
885 ctlr &= ~RCAR_CAN_CTLR_CANM;
886 writew(ctlr, &priv->regs->ctlr);
887 priv->can.state = CAN_STATE_ERROR_ACTIVE;
888
889 if (netif_running(ndev)) {
890 netif_device_attach(ndev);
891 netif_start_queue(ndev);
892 }
893 return 0;
894 }
895
896 static SIMPLE_DEV_PM_OPS(rcar_can_pm_ops, rcar_can_suspend, rcar_can_resume);
897
898 static const struct of_device_id rcar_can_of_table[] __maybe_unused = {
899 { .compatible = "renesas,can-r8a7778" },
900 { .compatible = "renesas,can-r8a7779" },
901 { .compatible = "renesas,can-r8a7790" },
902 { .compatible = "renesas,can-r8a7791" },
903 { }
904 };
905 MODULE_DEVICE_TABLE(of, rcar_can_of_table);
906
907 static struct platform_driver rcar_can_driver = {
908 .driver = {
909 .name = RCAR_CAN_DRV_NAME,
910 .owner = THIS_MODULE,
911 .of_match_table = of_match_ptr(rcar_can_of_table),
912 .pm = &rcar_can_pm_ops,
913 },
914 .probe = rcar_can_probe,
915 .remove = rcar_can_remove,
916 };
917
918 module_platform_driver(rcar_can_driver);
919
920 MODULE_AUTHOR("Cogent Embedded, Inc.");
921 MODULE_LICENSE("GPL");
922 MODULE_DESCRIPTION("CAN driver for Renesas R-Car SoC");
923 MODULE_ALIAS("platform:" RCAR_CAN_DRV_NAME);
924