1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * at91_can.c - CAN network driver for AT91 SoC CAN controller
   4 *
   5 * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
   6 * (C) 2008, 2009, 2010, 2011 by Marc Kleine-Budde <kernel@pengutronix.de>
   7 */
   8
   9#include <linux/clk.h>
  10#include <linux/errno.h>
  11#include <linux/if_arp.h>
  12#include <linux/interrupt.h>
  13#include <linux/kernel.h>
  14#include <linux/module.h>
  15#include <linux/netdevice.h>
  16#include <linux/of.h>
  17#include <linux/platform_device.h>
  18#include <linux/rtnetlink.h>
  19#include <linux/skbuff.h>
  20#include <linux/spinlock.h>
  21#include <linux/string.h>
  22#include <linux/types.h>
  23
  24#include <linux/can/dev.h>
  25#include <linux/can/error.h>
  26#include <linux/can/led.h>
  27
  28#define AT91_MB_MASK(i)		((1 << (i)) - 1)
  29
  30/* Common registers */
  31enum at91_reg {
  32	AT91_MR		= 0x000,
  33	AT91_IER	= 0x004,
  34	AT91_IDR	= 0x008,
  35	AT91_IMR	= 0x00C,
  36	AT91_SR		= 0x010,
  37	AT91_BR		= 0x014,
  38	AT91_TIM	= 0x018,
  39	AT91_TIMESTP	= 0x01C,
  40	AT91_ECR	= 0x020,
  41	AT91_TCR	= 0x024,
  42	AT91_ACR	= 0x028,
  43};
  44
  45/* Mailbox registers (0 <= i <= 15) */
  46#define AT91_MMR(i)		(enum at91_reg)(0x200 + ((i) * 0x20))
  47#define AT91_MAM(i)		(enum at91_reg)(0x204 + ((i) * 0x20))
  48#define AT91_MID(i)		(enum at91_reg)(0x208 + ((i) * 0x20))
  49#define AT91_MFID(i)		(enum at91_reg)(0x20C + ((i) * 0x20))
  50#define AT91_MSR(i)		(enum at91_reg)(0x210 + ((i) * 0x20))
  51#define AT91_MDL(i)		(enum at91_reg)(0x214 + ((i) * 0x20))
  52#define AT91_MDH(i)		(enum at91_reg)(0x218 + ((i) * 0x20))
  53#define AT91_MCR(i)		(enum at91_reg)(0x21C + ((i) * 0x20))
  54
  55/* Register bits */
  56#define AT91_MR_CANEN		BIT(0)
  57#define AT91_MR_LPM		BIT(1)
  58#define AT91_MR_ABM		BIT(2)
  59#define AT91_MR_OVL		BIT(3)
  60#define AT91_MR_TEOF		BIT(4)
  61#define AT91_MR_TTM		BIT(5)
  62#define AT91_MR_TIMFRZ		BIT(6)
  63#define AT91_MR_DRPT		BIT(7)
  64
  65#define AT91_SR_RBSY		BIT(29)
  66
  67#define AT91_MMR_PRIO_SHIFT	(16)
  68
  69#define AT91_MID_MIDE		BIT(29)
  70
  71#define AT91_MSR_MRTR		BIT(20)
  72#define AT91_MSR_MABT		BIT(22)
  73#define AT91_MSR_MRDY		BIT(23)
  74#define AT91_MSR_MMI		BIT(24)
  75
  76#define AT91_MCR_MRTR		BIT(20)
  77#define AT91_MCR_MTCR		BIT(23)
  78
  79/* Mailbox Modes */
  80enum at91_mb_mode {
  81	AT91_MB_MODE_DISABLED	= 0,
  82	AT91_MB_MODE_RX		= 1,
  83	AT91_MB_MODE_RX_OVRWR	= 2,
  84	AT91_MB_MODE_TX		= 3,
  85	AT91_MB_MODE_CONSUMER	= 4,
  86	AT91_MB_MODE_PRODUCER	= 5,
  87};
  88
  89/* Interrupt mask bits */
  90#define AT91_IRQ_ERRA		(1 << 16)
  91#define AT91_IRQ_WARN		(1 << 17)
  92#define AT91_IRQ_ERRP		(1 << 18)
  93#define AT91_IRQ_BOFF		(1 << 19)
  94#define AT91_IRQ_SLEEP		(1 << 20)
  95#define AT91_IRQ_WAKEUP		(1 << 21)
  96#define AT91_IRQ_TOVF		(1 << 22)
  97#define AT91_IRQ_TSTP		(1 << 23)
  98#define AT91_IRQ_CERR		(1 << 24)
  99#define AT91_IRQ_SERR		(1 << 25)
 100#define AT91_IRQ_AERR		(1 << 26)
 101#define AT91_IRQ_FERR		(1 << 27)
 102#define AT91_IRQ_BERR		(1 << 28)
 103
 104#define AT91_IRQ_ERR_ALL	(0x1fff0000)
 105#define AT91_IRQ_ERR_FRAME	(AT91_IRQ_CERR | AT91_IRQ_SERR | \
 106				 AT91_IRQ_AERR | AT91_IRQ_FERR | AT91_IRQ_BERR)
 107#define AT91_IRQ_ERR_LINE	(AT91_IRQ_ERRA | AT91_IRQ_WARN | \
 108				 AT91_IRQ_ERRP | AT91_IRQ_BOFF)
 109
 110#define AT91_IRQ_ALL		(0x1fffffff)
 111
 112enum at91_devtype {
 113	AT91_DEVTYPE_SAM9263,
 114	AT91_DEVTYPE_SAM9X5,
 115};
 116
 117struct at91_devtype_data {
 118	unsigned int rx_first;
 119	unsigned int rx_split;
 120	unsigned int rx_last;
 121	unsigned int tx_shift;
 122	enum at91_devtype type;
 123};
 124
 125struct at91_priv {
 126	struct can_priv can;		/* must be the first member! */
 127	struct napi_struct napi;
 128
 129	void __iomem *reg_base;
 130
 131	u32 reg_sr;
 132	unsigned int tx_next;
 133	unsigned int tx_echo;
 134	unsigned int rx_next;
 135	struct at91_devtype_data devtype_data;
 136
 137	struct clk *clk;
 138	struct at91_can_data *pdata;
 139
 140	canid_t mb0_id;
 141};
 142
 143static const struct at91_devtype_data at91_at91sam9263_data = {
 144	.rx_first = 1,
 145	.rx_split = 8,
 146	.rx_last = 11,
 147	.tx_shift = 2,
 148	.type = AT91_DEVTYPE_SAM9263,
 149};
 150
 151static const struct at91_devtype_data at91_at91sam9x5_data = {
 152	.rx_first = 0,
 153	.rx_split = 4,
 154	.rx_last = 5,
 155	.tx_shift = 1,
 156	.type = AT91_DEVTYPE_SAM9X5,
 157};
 158
 159static const struct can_bittiming_const at91_bittiming_const = {
 160	.name		= KBUILD_MODNAME,
 161	.tseg1_min	= 4,
 162	.tseg1_max	= 16,
 163	.tseg2_min	= 2,
 164	.tseg2_max	= 8,
 165	.sjw_max	= 4,
 166	.brp_min 	= 2,
 167	.brp_max	= 128,
 168	.brp_inc	= 1,
 169};
 170
 171#define AT91_IS(_model) \
 172static inline int at91_is_sam##_model(const struct at91_priv *priv) \
 173{ \
 174	return priv->devtype_data.type == AT91_DEVTYPE_SAM##_model; \
 175}
 176
 177AT91_IS(9263);
 178AT91_IS(9X5);
 179
 180static inline unsigned int get_mb_rx_first(const struct at91_priv *priv)
 181{
 182	return priv->devtype_data.rx_first;
 183}
 184
 185static inline unsigned int get_mb_rx_last(const struct at91_priv *priv)
 186{
 187	return priv->devtype_data.rx_last;
 188}
 189
 190static inline unsigned int get_mb_rx_split(const struct at91_priv *priv)
 191{
 192	return priv->devtype_data.rx_split;
 193}
 194
 195static inline unsigned int get_mb_rx_num(const struct at91_priv *priv)
 196{
 197	return get_mb_rx_last(priv) - get_mb_rx_first(priv) + 1;
 198}
 199
 200static inline unsigned int get_mb_rx_low_last(const struct at91_priv *priv)
 201{
 202	return get_mb_rx_split(priv) - 1;
 203}
 204
 205static inline unsigned int get_mb_rx_low_mask(const struct at91_priv *priv)
 206{
 207	return AT91_MB_MASK(get_mb_rx_split(priv)) &
 208		~AT91_MB_MASK(get_mb_rx_first(priv));
 209}
 210
 211static inline unsigned int get_mb_tx_shift(const struct at91_priv *priv)
 212{
 213	return priv->devtype_data.tx_shift;
 214}
 215
 216static inline unsigned int get_mb_tx_num(const struct at91_priv *priv)
 217{
 218	return 1 << get_mb_tx_shift(priv);
 219}
 220
 221static inline unsigned int get_mb_tx_first(const struct at91_priv *priv)
 222{
 223	return get_mb_rx_last(priv) + 1;
 224}
 225
 226static inline unsigned int get_mb_tx_last(const struct at91_priv *priv)
 227{
 228	return get_mb_tx_first(priv) + get_mb_tx_num(priv) - 1;
 229}
 230
 231static inline unsigned int get_next_prio_shift(const struct at91_priv *priv)
 232{
 233	return get_mb_tx_shift(priv);
 234}
 235
 236static inline unsigned int get_next_prio_mask(const struct at91_priv *priv)
 237{
 238	return 0xf << get_mb_tx_shift(priv);
 239}
 240
 241static inline unsigned int get_next_mb_mask(const struct at91_priv *priv)
 242{
 243	return AT91_MB_MASK(get_mb_tx_shift(priv));
 244}
 245
 246static inline unsigned int get_next_mask(const struct at91_priv *priv)
 247{
 248	return get_next_mb_mask(priv) | get_next_prio_mask(priv);
 249}
 250
 251static inline unsigned int get_irq_mb_rx(const struct at91_priv *priv)
 252{
 253	return AT91_MB_MASK(get_mb_rx_last(priv) + 1) &
 254		~AT91_MB_MASK(get_mb_rx_first(priv));
 255}
 256
 257static inline unsigned int get_irq_mb_tx(const struct at91_priv *priv)
 258{
 259	return AT91_MB_MASK(get_mb_tx_last(priv) + 1) &
 260		~AT91_MB_MASK(get_mb_tx_first(priv));
 261}
 262
 263static inline unsigned int get_tx_next_mb(const struct at91_priv *priv)
 264{
 265	return (priv->tx_next & get_next_mb_mask(priv)) + get_mb_tx_first(priv);
 266}
 267
 268static inline unsigned int get_tx_next_prio(const struct at91_priv *priv)
 269{
 270	return (priv->tx_next >> get_next_prio_shift(priv)) & 0xf;
 271}
 272
 273static inline unsigned int get_tx_echo_mb(const struct at91_priv *priv)
 274{
 275	return (priv->tx_echo & get_next_mb_mask(priv)) + get_mb_tx_first(priv);
 276}
 277
 278static inline u32 at91_read(const struct at91_priv *priv, enum at91_reg reg)
 279{
 280	return readl_relaxed(priv->reg_base + reg);
 281}
 282
 283static inline void at91_write(const struct at91_priv *priv, enum at91_reg reg,
 284		u32 value)
 285{
 286	writel_relaxed(value, priv->reg_base + reg);
 287}
 288
 289static inline void set_mb_mode_prio(const struct at91_priv *priv,
 290		unsigned int mb, enum at91_mb_mode mode, int prio)
 291{
 292	at91_write(priv, AT91_MMR(mb), (mode << 24) | (prio << 16));
 293}
 294
 295static inline void set_mb_mode(const struct at91_priv *priv, unsigned int mb,
 296		enum at91_mb_mode mode)
 297{
 298	set_mb_mode_prio(priv, mb, mode, 0);
 299}
 300
 301static inline u32 at91_can_id_to_reg_mid(canid_t can_id)
 302{
 303	u32 reg_mid;
 304
 305	if (can_id & CAN_EFF_FLAG)
 306		reg_mid = (can_id & CAN_EFF_MASK) | AT91_MID_MIDE;
 307	else
 308		reg_mid = (can_id & CAN_SFF_MASK) << 18;
 309
 310	return reg_mid;
 311}
 312
 313static void at91_setup_mailboxes(struct net_device *dev)
 314{
 315	struct at91_priv *priv = netdev_priv(dev);
 316	unsigned int i;
 317	u32 reg_mid;
 318
 319	/*
 320	 * Due to a chip bug (errata 50.2.6.3 & 50.3.5.3) the first
 321	 * mailbox is disabled. The next 11 mailboxes are used as a
 322	 * reception FIFO. The last mailbox is configured with
 323	 * overwrite option. The overwrite flag indicates a FIFO
 324	 * overflow.
 325	 */
 326	reg_mid = at91_can_id_to_reg_mid(priv->mb0_id);
 327	for (i = 0; i < get_mb_rx_first(priv); i++) {
 328		set_mb_mode(priv, i, AT91_MB_MODE_DISABLED);
 329		at91_write(priv, AT91_MID(i), reg_mid);
 330		at91_write(priv, AT91_MCR(i), 0x0);	/* clear dlc */
 331	}
 332
 333	for (i = get_mb_rx_first(priv); i < get_mb_rx_last(priv); i++)
 334		set_mb_mode(priv, i, AT91_MB_MODE_RX);
 335	set_mb_mode(priv, get_mb_rx_last(priv), AT91_MB_MODE_RX_OVRWR);
 336
 337	/* reset acceptance mask and id register */
 338	for (i = get_mb_rx_first(priv); i <= get_mb_rx_last(priv); i++) {
 339		at91_write(priv, AT91_MAM(i), 0x0);
 340		at91_write(priv, AT91_MID(i), AT91_MID_MIDE);
 341	}
 342
 343	/* The last 4 mailboxes are used for transmitting. */
 344	for (i = get_mb_tx_first(priv); i <= get_mb_tx_last(priv); i++)
 345		set_mb_mode_prio(priv, i, AT91_MB_MODE_TX, 0);
 346
 347	/* Reset tx and rx helper pointers */
 348	priv->tx_next = priv->tx_echo = 0;
 349	priv->rx_next = get_mb_rx_first(priv);
 350}
 351
 352static int at91_set_bittiming(struct net_device *dev)
 353{
 354	const struct at91_priv *priv = netdev_priv(dev);
 355	const struct can_bittiming *bt = &priv->can.bittiming;
 356	u32 reg_br;
 357
 358	reg_br = ((priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES) ? 1 << 24 : 0) |
 359		((bt->brp - 1) << 16) | ((bt->sjw - 1) << 12) |
 360		((bt->prop_seg - 1) << 8) | ((bt->phase_seg1 - 1) << 4) |
 361		((bt->phase_seg2 - 1) << 0);
 362
 363	netdev_info(dev, "writing AT91_BR: 0x%08x\n", reg_br);
 364
 365	at91_write(priv, AT91_BR, reg_br);
 366
 367	return 0;
 368}
 369
 370static int at91_get_berr_counter(const struct net_device *dev,
 371		struct can_berr_counter *bec)
 372{
 373	const struct at91_priv *priv = netdev_priv(dev);
 374	u32 reg_ecr = at91_read(priv, AT91_ECR);
 375
 376	bec->rxerr = reg_ecr & 0xff;
 377	bec->txerr = reg_ecr >> 16;
 378
 379	return 0;
 380}
 381
 382static void at91_chip_start(struct net_device *dev)
 383{
 384	struct at91_priv *priv = netdev_priv(dev);
 385	u32 reg_mr, reg_ier;
 386
 387	/* disable interrupts */
 388	at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
 389
 390	/* disable chip */
 391	reg_mr = at91_read(priv, AT91_MR);
 392	at91_write(priv, AT91_MR, reg_mr & ~AT91_MR_CANEN);
 393
 394	at91_set_bittiming(dev);
 395	at91_setup_mailboxes(dev);
 396
 397	/* enable chip */
 398	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
 399		reg_mr = AT91_MR_CANEN | AT91_MR_ABM;
 400	else
 401		reg_mr = AT91_MR_CANEN;
 402	at91_write(priv, AT91_MR, reg_mr);
 403
 404	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 405
 406	/* Enable interrupts */
 407	reg_ier = get_irq_mb_rx(priv) | AT91_IRQ_ERRP | AT91_IRQ_ERR_FRAME;
 408	at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
 409	at91_write(priv, AT91_IER, reg_ier);
 410}
 411
 412static void at91_chip_stop(struct net_device *dev, enum can_state state)
 413{
 414	struct at91_priv *priv = netdev_priv(dev);
 415	u32 reg_mr;
 416
 417	/* disable interrupts */
 418	at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
 419
 420	reg_mr = at91_read(priv, AT91_MR);
 421	at91_write(priv, AT91_MR, reg_mr & ~AT91_MR_CANEN);
 422
 423	priv->can.state = state;
 424}
 425
 426/*
 427 * theory of operation:
 428 *
 429 * According to the datasheet priority 0 is the highest priority, 15
 430 * is the lowest. If two mailboxes have the same priority level the
 431 * message of the mailbox with the lowest number is sent first.
 432 *
 433 * We use the first TX mailbox (AT91_MB_TX_FIRST) with prio 0, then
 434 * the next mailbox with prio 0, and so on, until all mailboxes are
 435 * used. Then we start from the beginning with mailbox
 436 * AT91_MB_TX_FIRST, but with prio 1, mailbox AT91_MB_TX_FIRST + 1
 437 * prio 1. When we reach the last mailbox with prio 15, we have to
 438 * stop sending, waiting for all messages to be delivered, then start
 439 * again with mailbox AT91_MB_TX_FIRST prio 0.
 440 *
 441 * We use the priv->tx_next as counter for the next transmission
 442 * mailbox, but without the offset AT91_MB_TX_FIRST. The lower bits
 443 * encode the mailbox number, the upper 4 bits the mailbox priority:
 444 *
 445 * priv->tx_next = (prio << get_next_prio_shift(priv)) |
 446 *                 (mb - get_mb_tx_first(priv));
 447 *
 448 */
 449static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
 450{
 451	struct at91_priv *priv = netdev_priv(dev);
 452	struct net_device_stats *stats = &dev->stats;
 453	struct can_frame *cf = (struct can_frame *)skb->data;
 454	unsigned int mb, prio;
 455	u32 reg_mid, reg_mcr;
 456
 457	if (can_dropped_invalid_skb(dev, skb))
 458		return NETDEV_TX_OK;
 459
 460	mb = get_tx_next_mb(priv);
 461	prio = get_tx_next_prio(priv);
 462
 463	if (unlikely(!(at91_read(priv, AT91_MSR(mb)) & AT91_MSR_MRDY))) {
 464		netif_stop_queue(dev);
 465
 466		netdev_err(dev, "BUG! TX buffer full when queue awake!\n");
 467		return NETDEV_TX_BUSY;
 468	}
 469	reg_mid = at91_can_id_to_reg_mid(cf->can_id);
 470	reg_mcr = ((cf->can_id & CAN_RTR_FLAG) ? AT91_MCR_MRTR : 0) |
 471		(cf->can_dlc << 16) | AT91_MCR_MTCR;
 472
 473	/* disable MB while writing ID (see datasheet) */
 474	set_mb_mode(priv, mb, AT91_MB_MODE_DISABLED);
 475	at91_write(priv, AT91_MID(mb), reg_mid);
 476	set_mb_mode_prio(priv, mb, AT91_MB_MODE_TX, prio);
 477
 478	at91_write(priv, AT91_MDL(mb), *(u32 *)(cf->data + 0));
 479	at91_write(priv, AT91_MDH(mb), *(u32 *)(cf->data + 4));
 480
 481	/* This triggers transmission */
 482	at91_write(priv, AT91_MCR(mb), reg_mcr);
 483
 484	stats->tx_bytes += cf->can_dlc;
 485
 486	/* _NOTE_: subtract AT91_MB_TX_FIRST offset from mb! */
 487	can_put_echo_skb(skb, dev, mb - get_mb_tx_first(priv));
 488
 489	/*
 490	 * we have to stop the queue and deliver all messages in case
 491	 * of a prio+mb counter wrap around. This is the case if
 492	 * tx_next buffer prio and mailbox equals 0.
 493	 *
 494	 * also stop the queue if next buffer is still in use
 495	 * (== not ready)
 496	 */
 497	priv->tx_next++;
 498	if (!(at91_read(priv, AT91_MSR(get_tx_next_mb(priv))) &
 499	      AT91_MSR_MRDY) ||
 500	    (priv->tx_next & get_next_mask(priv)) == 0)
 501		netif_stop_queue(dev);
 502
 503	/* Enable interrupt for this mailbox */
 504	at91_write(priv, AT91_IER, 1 << mb);
 505
 506	return NETDEV_TX_OK;
 507}
 508
 509/**
 510 * at91_activate_rx_low - activate lower rx mailboxes
 511 * @priv: a91 context
 512 *
 513 * Reenables the lower mailboxes for reception of new CAN messages
 514 */
 515static inline void at91_activate_rx_low(const struct at91_priv *priv)
 516{
 517	u32 mask = get_mb_rx_low_mask(priv);
 518	at91_write(priv, AT91_TCR, mask);
 519}
 520
 521/**
 522 * at91_activate_rx_mb - reactive single rx mailbox
 523 * @priv: a91 context
 524 * @mb: mailbox to reactivate
 525 *
 526 * Reenables given mailbox for reception of new CAN messages
 527 */
 528static inline void at91_activate_rx_mb(const struct at91_priv *priv,
 529		unsigned int mb)
 530{
 531	u32 mask = 1 << mb;
 532	at91_write(priv, AT91_TCR, mask);
 533}
 534
 535/**
 536 * at91_rx_overflow_err - send error frame due to rx overflow
 537 * @dev: net device
 538 */
 539static void at91_rx_overflow_err(struct net_device *dev)
 540{
 541	struct net_device_stats *stats = &dev->stats;
 542	struct sk_buff *skb;
 543	struct can_frame *cf;
 544
 545	netdev_dbg(dev, "RX buffer overflow\n");
 546	stats->rx_over_errors++;
 547	stats->rx_errors++;
 548
 549	skb = alloc_can_err_skb(dev, &cf);
 550	if (unlikely(!skb))
 551		return;
 552
 553	cf->can_id |= CAN_ERR_CRTL;
 554	cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 555
 556	stats->rx_packets++;
 557	stats->rx_bytes += cf->can_dlc;
 558	netif_receive_skb(skb);
 559}
 560
 561/**
 562 * at91_read_mb - read CAN msg from mailbox (lowlevel impl)
 563 * @dev: net device
 564 * @mb: mailbox number to read from
 565 * @cf: can frame where to store message
 566 *
 567 * Reads a CAN message from the given mailbox and stores data into
 568 * given can frame. "mb" and "cf" must be valid.
 569 */
 570static void at91_read_mb(struct net_device *dev, unsigned int mb,
 571		struct can_frame *cf)
 572{
 573	const struct at91_priv *priv = netdev_priv(dev);
 574	u32 reg_msr, reg_mid;
 575
 576	reg_mid = at91_read(priv, AT91_MID(mb));
 577	if (reg_mid & AT91_MID_MIDE)
 578		cf->can_id = ((reg_mid >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
 579	else
 580		cf->can_id = (reg_mid >> 18) & CAN_SFF_MASK;
 581
 582	reg_msr = at91_read(priv, AT91_MSR(mb));
 583	cf->can_dlc = get_can_dlc((reg_msr >> 16) & 0xf);
 584
 585	if (reg_msr & AT91_MSR_MRTR)
 586		cf->can_id |= CAN_RTR_FLAG;
 587	else {
 588		*(u32 *)(cf->data + 0) = at91_read(priv, AT91_MDL(mb));
 589		*(u32 *)(cf->data + 4) = at91_read(priv, AT91_MDH(mb));
 590	}
 591
 592	/* allow RX of extended frames */
 593	at91_write(priv, AT91_MID(mb), AT91_MID_MIDE);
 594
 595	if (unlikely(mb == get_mb_rx_last(priv) && reg_msr & AT91_MSR_MMI))
 596		at91_rx_overflow_err(dev);
 597}
 598
 599/**
 600 * at91_read_msg - read CAN message from mailbox
 601 * @dev: net device
 602 * @mb: mail box to read from
 603 *
 604 * Reads a CAN message from given mailbox, and put into linux network
 605 * RX queue, does all housekeeping chores (stats, ...)
 606 */
 607static void at91_read_msg(struct net_device *dev, unsigned int mb)
 608{
 609	struct net_device_stats *stats = &dev->stats;
 610	struct can_frame *cf;
 611	struct sk_buff *skb;
 612
 613	skb = alloc_can_skb(dev, &cf);
 614	if (unlikely(!skb)) {
 615		stats->rx_dropped++;
 616		return;
 617	}
 618
 619	at91_read_mb(dev, mb, cf);
 620
 621	stats->rx_packets++;
 622	stats->rx_bytes += cf->can_dlc;
 623	netif_receive_skb(skb);
 624
 625	can_led_event(dev, CAN_LED_EVENT_RX);
 626}
 627
 628/**
 629 * at91_poll_rx - read multiple CAN messages from mailboxes
 630 * @dev: net device
 631 * @quota: max number of pkgs we're allowed to receive
 632 *
 633 * Theory of Operation:
 634 *
 635 * About 3/4 of the mailboxes (get_mb_rx_first()...get_mb_rx_last())
 636 * on the chip are reserved for RX. We split them into 2 groups. The
 637 * lower group ranges from get_mb_rx_first() to get_mb_rx_low_last().
 638 *
 639 * Like it or not, but the chip always saves a received CAN message
 640 * into the first free mailbox it finds (starting with the
 641 * lowest). This makes it very difficult to read the messages in the
 642 * right order from the chip. This is how we work around that problem:
 643 *
 644 * The first message goes into mb nr. 1 and issues an interrupt. All
 645 * rx ints are disabled in the interrupt handler and a napi poll is
 646 * scheduled. We read the mailbox, but do _not_ reenable the mb (to
 647 * receive another message).
 648 *
 649 *    lower mbxs      upper
 650 *     ____^______    __^__
 651 *    /           \  /     \
 652 * +-+-+-+-+-+-+-+-++-+-+-+-+
 653 * | |x|x|x|x|x|x|x|| | | | |
 654 * +-+-+-+-+-+-+-+-++-+-+-+-+
 655 *  0 0 0 0 0 0  0 0 0 0 1 1  \ mail
 656 *  0 1 2 3 4 5  6 7 8 9 0 1  / box
 657 *  ^
 658 *  |
 659 *   \
 660 *     unused, due to chip bug
 661 *
 662 * The variable priv->rx_next points to the next mailbox to read a
 663 * message from. As long we're in the lower mailboxes we just read the
 664 * mailbox but not reenable it.
 665 *
 666 * With completion of the last of the lower mailboxes, we reenable the
 667 * whole first group, but continue to look for filled mailboxes in the
 668 * upper mailboxes. Imagine the second group like overflow mailboxes,
 669 * which takes CAN messages if the lower goup is full. While in the
 670 * upper group we reenable the mailbox right after reading it. Giving
 671 * the chip more room to store messages.
 672 *
 673 * After finishing we look again in the lower group if we've still
 674 * quota.
 675 *
 676 */
 677static int at91_poll_rx(struct net_device *dev, int quota)
 678{
 679	struct at91_priv *priv = netdev_priv(dev);
 680	u32 reg_sr = at91_read(priv, AT91_SR);
 681	const unsigned long *addr = (unsigned long *)&reg_sr;
 682	unsigned int mb;
 683	int received = 0;
 684
 685	if (priv->rx_next > get_mb_rx_low_last(priv) &&
 686	    reg_sr & get_mb_rx_low_mask(priv))
 687		netdev_info(dev,
 688			"order of incoming frames cannot be guaranteed\n");
 689
 690 again:
 691	for (mb = find_next_bit(addr, get_mb_tx_first(priv), priv->rx_next);
 692	     mb < get_mb_tx_first(priv) && quota > 0;
 693	     reg_sr = at91_read(priv, AT91_SR),
 694	     mb = find_next_bit(addr, get_mb_tx_first(priv), ++priv->rx_next)) {
 695		at91_read_msg(dev, mb);
 696
 697		/* reactivate mailboxes */
 698		if (mb == get_mb_rx_low_last(priv))
 699			/* all lower mailboxed, if just finished it */
 700			at91_activate_rx_low(priv);
 701		else if (mb > get_mb_rx_low_last(priv))
 702			/* only the mailbox we read */
 703			at91_activate_rx_mb(priv, mb);
 704
 705		received++;
 706		quota--;
 707	}
 708
 709	/* upper group completed, look again in lower */
 710	if (priv->rx_next > get_mb_rx_low_last(priv) &&
 711	    mb > get_mb_rx_last(priv)) {
 712		priv->rx_next = get_mb_rx_first(priv);
 713		if (quota > 0)
 714			goto again;
 715	}
 716
 717	return received;
 718}
 719
 720static void at91_poll_err_frame(struct net_device *dev,
 721		struct can_frame *cf, u32 reg_sr)
 722{
 723	struct at91_priv *priv = netdev_priv(dev);
 724
 725	/* CRC error */
 726	if (reg_sr & AT91_IRQ_CERR) {
 727		netdev_dbg(dev, "CERR irq\n");
 728		dev->stats.rx_errors++;
 729		priv->can.can_stats.bus_error++;
 730		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 731	}
 732
 733	/* Stuffing Error */
 734	if (reg_sr & AT91_IRQ_SERR) {
 735		netdev_dbg(dev, "SERR irq\n");
 736		dev->stats.rx_errors++;
 737		priv->can.can_stats.bus_error++;
 738		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 739		cf->data[2] |= CAN_ERR_PROT_STUFF;
 740	}
 741
 742	/* Acknowledgement Error */
 743	if (reg_sr & AT91_IRQ_AERR) {
 744		netdev_dbg(dev, "AERR irq\n");
 745		dev->stats.tx_errors++;
 746		cf->can_id |= CAN_ERR_ACK;
 747	}
 748
 749	/* Form error */
 750	if (reg_sr & AT91_IRQ_FERR) {
 751		netdev_dbg(dev, "FERR irq\n");
 752		dev->stats.rx_errors++;
 753		priv->can.can_stats.bus_error++;
 754		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 755		cf->data[2] |= CAN_ERR_PROT_FORM;
 756	}
 757
 758	/* Bit Error */
 759	if (reg_sr & AT91_IRQ_BERR) {
 760		netdev_dbg(dev, "BERR irq\n");
 761		dev->stats.tx_errors++;
 762		priv->can.can_stats.bus_error++;
 763		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 764		cf->data[2] |= CAN_ERR_PROT_BIT;
 765	}
 766}
 767
 768static int at91_poll_err(struct net_device *dev, int quota, u32 reg_sr)
 769{
 770	struct sk_buff *skb;
 771	struct can_frame *cf;
 772
 773	if (quota == 0)
 774		return 0;
 775
 776	skb = alloc_can_err_skb(dev, &cf);
 777	if (unlikely(!skb))
 778		return 0;
 779
 780	at91_poll_err_frame(dev, cf, reg_sr);
 781
 782	dev->stats.rx_packets++;
 783	dev->stats.rx_bytes += cf->can_dlc;
 784	netif_receive_skb(skb);
 785
 786	return 1;
 787}
 788
 789static int at91_poll(struct napi_struct *napi, int quota)
 790{
 791	struct net_device *dev = napi->dev;
 792	const struct at91_priv *priv = netdev_priv(dev);
 793	u32 reg_sr = at91_read(priv, AT91_SR);
 794	int work_done = 0;
 795
 796	if (reg_sr & get_irq_mb_rx(priv))
 797		work_done += at91_poll_rx(dev, quota - work_done);
 798
 799	/*
 800	 * The error bits are clear on read,
 801	 * so use saved value from irq handler.
 802	 */
 803	reg_sr |= priv->reg_sr;
 804	if (reg_sr & AT91_IRQ_ERR_FRAME)
 805		work_done += at91_poll_err(dev, quota - work_done, reg_sr);
 806
 807	if (work_done < quota) {
 808		/* enable IRQs for frame errors and all mailboxes >= rx_next */
 809		u32 reg_ier = AT91_IRQ_ERR_FRAME;
 810		reg_ier |= get_irq_mb_rx(priv) & ~AT91_MB_MASK(priv->rx_next);
 811
 812		napi_complete_done(napi, work_done);
 813		at91_write(priv, AT91_IER, reg_ier);
 814	}
 815
 816	return work_done;
 817}
 818
 819/*
 820 * theory of operation:
 821 *
 822 * priv->tx_echo holds the number of the oldest can_frame put for
 823 * transmission into the hardware, but not yet ACKed by the CAN tx
 824 * complete IRQ.
 825 *
 826 * We iterate from priv->tx_echo to priv->tx_next and check if the
 827 * packet has been transmitted, echo it back to the CAN framework. If
 828 * we discover a not yet transmitted package, stop looking for more.
 829 *
 830 */
 831static void at91_irq_tx(struct net_device *dev, u32 reg_sr)
 832{
 833	struct at91_priv *priv = netdev_priv(dev);
 834	u32 reg_msr;
 835	unsigned int mb;
 836
 837	/* masking of reg_sr not needed, already done by at91_irq */
 838
 839	for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
 840		mb = get_tx_echo_mb(priv);
 841
 842		/* no event in mailbox? */
 843		if (!(reg_sr & (1 << mb)))
 844			break;
 845
 846		/* Disable irq for this TX mailbox */
 847		at91_write(priv, AT91_IDR, 1 << mb);
 848
 849		/*
 850		 * only echo if mailbox signals us a transfer
 851		 * complete (MSR_MRDY). Otherwise it's a tansfer
 852		 * abort. "can_bus_off()" takes care about the skbs
 853		 * parked in the echo queue.
 854		 */
 855		reg_msr = at91_read(priv, AT91_MSR(mb));
 856		if (likely(reg_msr & AT91_MSR_MRDY &&
 857			   ~reg_msr & AT91_MSR_MABT)) {
 858			/* _NOTE_: subtract AT91_MB_TX_FIRST offset from mb! */
 859			can_get_echo_skb(dev, mb - get_mb_tx_first(priv));
 860			dev->stats.tx_packets++;
 861			can_led_event(dev, CAN_LED_EVENT_TX);
 862		}
 863	}
 864
 865	/*
 866	 * restart queue if we don't have a wrap around but restart if
 867	 * we get a TX int for the last can frame directly before a
 868	 * wrap around.
 869	 */
 870	if ((priv->tx_next & get_next_mask(priv)) != 0 ||
 871	    (priv->tx_echo & get_next_mask(priv)) == 0)
 872		netif_wake_queue(dev);
 873}
 874
 875static void at91_irq_err_state(struct net_device *dev,
 876		struct can_frame *cf, enum can_state new_state)
 877{
 878	struct at91_priv *priv = netdev_priv(dev);
 879	u32 reg_idr = 0, reg_ier = 0;
 880	struct can_berr_counter bec;
 881
 882	at91_get_berr_counter(dev, &bec);
 883
 884	switch (priv->can.state) {
 885	case CAN_STATE_ERROR_ACTIVE:
 886		/*
 887		 * from: ERROR_ACTIVE
 888		 * to  : ERROR_WARNING, ERROR_PASSIVE, BUS_OFF
 889		 * =>  : there was a warning int
 890		 */
 891		if (new_state >= CAN_STATE_ERROR_WARNING &&
 892		    new_state <= CAN_STATE_BUS_OFF) {
 893			netdev_dbg(dev, "Error Warning IRQ\n");
 894			priv->can.can_stats.error_warning++;
 895
 896			cf->can_id |= CAN_ERR_CRTL;
 897			cf->data[1] = (bec.txerr > bec.rxerr) ?
 898				CAN_ERR_CRTL_TX_WARNING :
 899				CAN_ERR_CRTL_RX_WARNING;
 900		}
 901		fallthrough;
 902	case CAN_STATE_ERROR_WARNING:
 903		/*
 904		 * from: ERROR_ACTIVE, ERROR_WARNING
 905		 * to  : ERROR_PASSIVE, BUS_OFF
 906		 * =>  : error passive int
 907		 */
 908		if (new_state >= CAN_STATE_ERROR_PASSIVE &&
 909		    new_state <= CAN_STATE_BUS_OFF) {
 910			netdev_dbg(dev, "Error Passive IRQ\n");
 911			priv->can.can_stats.error_passive++;
 912
 913			cf->can_id |= CAN_ERR_CRTL;
 914			cf->data[1] = (bec.txerr > bec.rxerr) ?
 915				CAN_ERR_CRTL_TX_PASSIVE :
 916				CAN_ERR_CRTL_RX_PASSIVE;
 917		}
 918		break;
 919	case CAN_STATE_BUS_OFF:
 920		/*
 921		 * from: BUS_OFF
 922		 * to  : ERROR_ACTIVE, ERROR_WARNING, ERROR_PASSIVE
 923		 */
 924		if (new_state <= CAN_STATE_ERROR_PASSIVE) {
 925			cf->can_id |= CAN_ERR_RESTARTED;
 926
 927			netdev_dbg(dev, "restarted\n");
 928			priv->can.can_stats.restarts++;
 929
 930			netif_carrier_on(dev);
 931			netif_wake_queue(dev);
 932		}
 933		break;
 934	default:
 935		break;
 936	}
 937
 938
 939	/* process state changes depending on the new state */
 940	switch (new_state) {
 941	case CAN_STATE_ERROR_ACTIVE:
 942		/*
 943		 * actually we want to enable AT91_IRQ_WARN here, but
 944		 * it screws up the system under certain
 945		 * circumstances. so just enable AT91_IRQ_ERRP, thus
 946		 * the "fallthrough"
 947		 */
 948		netdev_dbg(dev, "Error Active\n");
 949		cf->can_id |= CAN_ERR_PROT;
 950		cf->data[2] = CAN_ERR_PROT_ACTIVE;
 951		fallthrough;
 952	case CAN_STATE_ERROR_WARNING:
 953		reg_idr = AT91_IRQ_ERRA | AT91_IRQ_WARN | AT91_IRQ_BOFF;
 954		reg_ier = AT91_IRQ_ERRP;
 955		break;
 956	case CAN_STATE_ERROR_PASSIVE:
 957		reg_idr = AT91_IRQ_ERRA | AT91_IRQ_WARN | AT91_IRQ_ERRP;
 958		reg_ier = AT91_IRQ_BOFF;
 959		break;
 960	case CAN_STATE_BUS_OFF:
 961		reg_idr = AT91_IRQ_ERRA | AT91_IRQ_ERRP |
 962			AT91_IRQ_WARN | AT91_IRQ_BOFF;
 963		reg_ier = 0;
 964
 965		cf->can_id |= CAN_ERR_BUSOFF;
 966
 967		netdev_dbg(dev, "bus-off\n");
 968		netif_carrier_off(dev);
 969		priv->can.can_stats.bus_off++;
 970
 971		/* turn off chip, if restart is disabled */
 972		if (!priv->can.restart_ms) {
 973			at91_chip_stop(dev, CAN_STATE_BUS_OFF);
 974			return;
 975		}
 976		break;
 977	default:
 978		break;
 979	}
 980
 981	at91_write(priv, AT91_IDR, reg_idr);
 982	at91_write(priv, AT91_IER, reg_ier);
 983}
 984
 985static int at91_get_state_by_bec(const struct net_device *dev,
 986		enum can_state *state)
 987{
 988	struct can_berr_counter bec;
 989	int err;
 990
 991	err = at91_get_berr_counter(dev, &bec);
 992	if (err)
 993		return err;
 994
 995	if (bec.txerr < 96 && bec.rxerr < 96)
 996		*state = CAN_STATE_ERROR_ACTIVE;
 997	else if (bec.txerr < 128 && bec.rxerr < 128)
 998		*state = CAN_STATE_ERROR_WARNING;
 999	else if (bec.txerr < 256 && bec.rxerr < 256)
1000		*state = CAN_STATE_ERROR_PASSIVE;
1001	else
1002		*state = CAN_STATE_BUS_OFF;
1003
1004	return 0;
1005}
1006
1007
1008static void at91_irq_err(struct net_device *dev)
1009{
1010	struct at91_priv *priv = netdev_priv(dev);
1011	struct sk_buff *skb;
1012	struct can_frame *cf;
1013	enum can_state new_state;
1014	u32 reg_sr;
1015	int err;
1016
1017	if (at91_is_sam9263(priv)) {
1018		reg_sr = at91_read(priv, AT91_SR);
1019
1020		/* we need to look at the unmasked reg_sr */
1021		if (unlikely(reg_sr & AT91_IRQ_BOFF))
1022			new_state = CAN_STATE_BUS_OFF;
1023		else if (unlikely(reg_sr & AT91_IRQ_ERRP))
1024			new_state = CAN_STATE_ERROR_PASSIVE;
1025		else if (unlikely(reg_sr & AT91_IRQ_WARN))
1026			new_state = CAN_STATE_ERROR_WARNING;
1027		else if (likely(reg_sr & AT91_IRQ_ERRA))
1028			new_state = CAN_STATE_ERROR_ACTIVE;
1029		else {
1030			netdev_err(dev, "BUG! hardware in undefined state\n");
1031			return;
1032		}
1033	} else {
1034		err = at91_get_state_by_bec(dev, &new_state);
1035		if (err)
1036			return;
1037	}
1038
1039	/* state hasn't changed */
1040	if (likely(new_state == priv->can.state))
1041		return;
1042
1043	skb = alloc_can_err_skb(dev, &cf);
1044	if (unlikely(!skb))
1045		return;
1046
1047	at91_irq_err_state(dev, cf, new_state);
1048
1049	dev->stats.rx_packets++;
1050	dev->stats.rx_bytes += cf->can_dlc;
1051	netif_rx(skb);
1052
1053	priv->can.state = new_state;
1054}
1055
1056/*
1057 * interrupt handler
1058 */
1059static irqreturn_t at91_irq(int irq, void *dev_id)
1060{
1061	struct net_device *dev = dev_id;
1062	struct at91_priv *priv = netdev_priv(dev);
1063	irqreturn_t handled = IRQ_NONE;
1064	u32 reg_sr, reg_imr;
1065
1066	reg_sr = at91_read(priv, AT91_SR);
1067	reg_imr = at91_read(priv, AT91_IMR);
1068
1069	/* Ignore masked interrupts */
1070	reg_sr &= reg_imr;
1071	if (!reg_sr)
1072		goto exit;
1073
1074	handled = IRQ_HANDLED;
1075
1076	/* Receive or error interrupt? -> napi */
1077	if (reg_sr & (get_irq_mb_rx(priv) | AT91_IRQ_ERR_FRAME)) {
1078		/*
1079		 * The error bits are clear on read,
1080		 * save for later use.
1081		 */
1082		priv->reg_sr = reg_sr;
1083		at91_write(priv, AT91_IDR,
1084			   get_irq_mb_rx(priv) | AT91_IRQ_ERR_FRAME);
1085		napi_schedule(&priv->napi);
1086	}
1087
1088	/* Transmission complete interrupt */
1089	if (reg_sr & get_irq_mb_tx(priv))
1090		at91_irq_tx(dev, reg_sr);
1091
1092	at91_irq_err(dev);
1093
1094 exit:
1095	return handled;
1096}
1097
1098static int at91_open(struct net_device *dev)
1099{
1100	struct at91_priv *priv = netdev_priv(dev);
1101	int err;
1102
1103	err = clk_prepare_enable(priv->clk);
1104	if (err)
1105		return err;
1106
1107	/* check or determine and set bittime */
1108	err = open_candev(dev);
1109	if (err)
1110		goto out;
1111
1112	/* register interrupt handler */
1113	if (request_irq(dev->irq, at91_irq, IRQF_SHARED,
1114			dev->name, dev)) {
1115		err = -EAGAIN;
1116		goto out_close;
1117	}
1118
1119	can_led_event(dev, CAN_LED_EVENT_OPEN);
1120
1121	/* start chip and queuing */
1122	at91_chip_start(dev);
1123	napi_enable(&priv->napi);
1124	netif_start_queue(dev);
1125
1126	return 0;
1127
1128 out_close:
1129	close_candev(dev);
1130 out:
1131	clk_disable_unprepare(priv->clk);
1132
1133	return err;
1134}
1135
1136/*
1137 * stop CAN bus activity
1138 */
1139static int at91_close(struct net_device *dev)
1140{
1141	struct at91_priv *priv = netdev_priv(dev);
1142
1143	netif_stop_queue(dev);
1144	napi_disable(&priv->napi);
1145	at91_chip_stop(dev, CAN_STATE_STOPPED);
1146
1147	free_irq(dev->irq, dev);
1148	clk_disable_unprepare(priv->clk);
1149
1150	close_candev(dev);
1151
1152	can_led_event(dev, CAN_LED_EVENT_STOP);
1153
1154	return 0;
1155}
1156
1157static int at91_set_mode(struct net_device *dev, enum can_mode mode)
1158{
1159	switch (mode) {
1160	case CAN_MODE_START:
1161		at91_chip_start(dev);
1162		netif_wake_queue(dev);
1163		break;
1164
1165	default:
1166		return -EOPNOTSUPP;
1167	}
1168
1169	return 0;
1170}
1171
1172static const struct net_device_ops at91_netdev_ops = {
1173	.ndo_open	= at91_open,
1174	.ndo_stop	= at91_close,
1175	.ndo_start_xmit	= at91_start_xmit,
1176	.ndo_change_mtu = can_change_mtu,
1177};
1178
1179static ssize_t at91_sysfs_show_mb0_id(struct device *dev,
1180		struct device_attribute *attr, char *buf)
1181{
1182	struct at91_priv *priv = netdev_priv(to_net_dev(dev));
1183
1184	if (priv->mb0_id & CAN_EFF_FLAG)
1185		return snprintf(buf, PAGE_SIZE, "0x%08x\n", priv->mb0_id);
1186	else
1187		return snprintf(buf, PAGE_SIZE, "0x%03x\n", priv->mb0_id);
1188}
1189
1190static ssize_t at91_sysfs_set_mb0_id(struct device *dev,
1191		struct device_attribute *attr, const char *buf, size_t count)
1192{
1193	struct net_device *ndev = to_net_dev(dev);
1194	struct at91_priv *priv = netdev_priv(ndev);
1195	unsigned long can_id;
1196	ssize_t ret;
1197	int err;
1198
1199	rtnl_lock();
1200
1201	if (ndev->flags & IFF_UP) {
1202		ret = -EBUSY;
1203		goto out;
1204	}
1205
1206	err = kstrtoul(buf, 0, &can_id);
1207	if (err) {
1208		ret = err;
1209		goto out;
1210	}
1211
1212	if (can_id & CAN_EFF_FLAG)
1213		can_id &= CAN_EFF_MASK | CAN_EFF_FLAG;
1214	else
1215		can_id &= CAN_SFF_MASK;
1216
1217	priv->mb0_id = can_id;
1218	ret = count;
1219
1220 out:
1221	rtnl_unlock();
1222	return ret;
1223}
1224
1225static DEVICE_ATTR(mb0_id, 0644, at91_sysfs_show_mb0_id, at91_sysfs_set_mb0_id);
1226
1227static struct attribute *at91_sysfs_attrs[] = {
1228	&dev_attr_mb0_id.attr,
1229	NULL,
1230};
1231
1232static const struct attribute_group at91_sysfs_attr_group = {
1233	.attrs = at91_sysfs_attrs,
1234};
1235
1236#if defined(CONFIG_OF)
1237static const struct of_device_id at91_can_dt_ids[] = {
1238	{
1239		.compatible = "atmel,at91sam9x5-can",
1240		.data = &at91_at91sam9x5_data,
1241	}, {
1242		.compatible = "atmel,at91sam9263-can",
1243		.data = &at91_at91sam9263_data,
1244	}, {
1245		/* sentinel */
1246	}
1247};
1248MODULE_DEVICE_TABLE(of, at91_can_dt_ids);
1249#endif
1250
1251static const struct at91_devtype_data *at91_can_get_driver_data(struct platform_device *pdev)
1252{
1253	if (pdev->dev.of_node) {
1254		const struct of_device_id *match;
1255
1256		match = of_match_node(at91_can_dt_ids, pdev->dev.of_node);
1257		if (!match) {
1258			dev_err(&pdev->dev, "no matching node found in dtb\n");
1259			return NULL;
1260		}
1261		return (const struct at91_devtype_data *)match->data;
1262	}
1263	return (const struct at91_devtype_data *)
1264		platform_get_device_id(pdev)->driver_data;
1265}
1266
1267static int at91_can_probe(struct platform_device *pdev)
1268{
1269	const struct at91_devtype_data *devtype_data;
1270	struct net_device *dev;
1271	struct at91_priv *priv;
1272	struct resource *res;
1273	struct clk *clk;
1274	void __iomem *addr;
1275	int err, irq;
1276
1277	devtype_data = at91_can_get_driver_data(pdev);
1278	if (!devtype_data) {
1279		dev_err(&pdev->dev, "no driver data\n");
1280		err = -ENODEV;
1281		goto exit;
1282	}
1283
1284	clk = clk_get(&pdev->dev, "can_clk");
1285	if (IS_ERR(clk)) {
1286		dev_err(&pdev->dev, "no clock defined\n");
1287		err = -ENODEV;
1288		goto exit;
1289	}
1290
1291	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1292	irq = platform_get_irq(pdev, 0);
1293	if (!res || irq <= 0) {
1294		err = -ENODEV;
1295		goto exit_put;
1296	}
1297
1298	if (!request_mem_region(res->start,
1299				resource_size(res),
1300				pdev->name)) {
1301		err = -EBUSY;
1302		goto exit_put;
1303	}
1304
1305	addr = ioremap(res->start, resource_size(res));
1306	if (!addr) {
1307		err = -ENOMEM;
1308		goto exit_release;
1309	}
1310
1311	dev = alloc_candev(sizeof(struct at91_priv),
1312			   1 << devtype_data->tx_shift);
1313	if (!dev) {
1314		err = -ENOMEM;
1315		goto exit_iounmap;
1316	}
1317
1318	dev->netdev_ops	= &at91_netdev_ops;
1319	dev->irq = irq;
1320	dev->flags |= IFF_ECHO;
1321
1322	priv = netdev_priv(dev);
1323	priv->can.clock.freq = clk_get_rate(clk);
1324	priv->can.bittiming_const = &at91_bittiming_const;
1325	priv->can.do_set_mode = at91_set_mode;
1326	priv->can.do_get_berr_counter = at91_get_berr_counter;
1327	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
1328		CAN_CTRLMODE_LISTENONLY;
1329	priv->reg_base = addr;
1330	priv->devtype_data = *devtype_data;
1331	priv->clk = clk;
1332	priv->pdata = dev_get_platdata(&pdev->dev);
1333	priv->mb0_id = 0x7ff;
1334
1335	netif_napi_add(dev, &priv->napi, at91_poll, get_mb_rx_num(priv));
1336
1337	if (at91_is_sam9263(priv))
1338		dev->sysfs_groups[0] = &at91_sysfs_attr_group;
1339
1340	platform_set_drvdata(pdev, dev);
1341	SET_NETDEV_DEV(dev, &pdev->dev);
1342
1343	err = register_candev(dev);
1344	if (err) {
1345		dev_err(&pdev->dev, "registering netdev failed\n");
1346		goto exit_free;
1347	}
1348
1349	devm_can_led_init(dev);
1350
1351	dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
1352		 priv->reg_base, dev->irq);
1353
1354	return 0;
1355
1356 exit_free:
1357	free_candev(dev);
1358 exit_iounmap:
1359	iounmap(addr);
1360 exit_release:
1361	release_mem_region(res->start, resource_size(res));
1362 exit_put:
1363	clk_put(clk);
1364 exit:
1365	return err;
1366}
1367
1368static int at91_can_remove(struct platform_device *pdev)
1369{
1370	struct net_device *dev = platform_get_drvdata(pdev);
1371	struct at91_priv *priv = netdev_priv(dev);
1372	struct resource *res;
1373
1374	unregister_netdev(dev);
1375
1376	iounmap(priv->reg_base);
1377
1378	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1379	release_mem_region(res->start, resource_size(res));
1380
1381	clk_put(priv->clk);
1382
1383	free_candev(dev);
1384
1385	return 0;
1386}
1387
1388static const struct platform_device_id at91_can_id_table[] = {
1389	{
1390		.name = "at91sam9x5_can",
1391		.driver_data = (kernel_ulong_t)&at91_at91sam9x5_data,
1392	}, {
1393		.name = "at91_can",
1394		.driver_data = (kernel_ulong_t)&at91_at91sam9263_data,
1395	}, {
1396		/* sentinel */
1397	}
1398};
1399MODULE_DEVICE_TABLE(platform, at91_can_id_table);
1400
1401static struct platform_driver at91_can_driver = {
1402	.probe = at91_can_probe,
1403	.remove = at91_can_remove,
1404	.driver = {
1405		.name = KBUILD_MODNAME,
1406		.of_match_table = of_match_ptr(at91_can_dt_ids),
1407	},
1408	.id_table = at91_can_id_table,
1409};
1410
1411module_platform_driver(at91_can_driver);
1412
1413MODULE_AUTHOR("Marc Kleine-Budde <mkl@pengutronix.de>");
1414MODULE_LICENSE("GPL v2");
1415MODULE_DESCRIPTION(KBUILD_MODNAME " CAN netdevice driver");