2 * CAN bus driver for Bosch C_CAN controller
4 * Copyright (C) 2010 ST Microelectronics
5 * Bhupesh Sharma <bhupesh.sharma@st.com>
7 * Borrowed heavily from the C_CAN driver originally written by:
9 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
10 * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
12 * TX and RX NAPI implementation has been borrowed from at91 CAN driver
15 * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
16 * (C) 2008, 2009 by Marc Kleine-Budde <kernel@pengutronix.de>
18 * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
19 * Bosch C_CAN user manual can be obtained from:
20 * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
21 * users_manual_c_can.pdf
23 * This file is licensed under the terms of the GNU General Public
24 * License version 2. This program is licensed "as is" without any
25 * warranty of any kind, whether express or implied.
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/interrupt.h>
31 #include <linux/delay.h>
32 #include <linux/netdevice.h>
33 #include <linux/if_arp.h>
34 #include <linux/if_ether.h>
35 #include <linux/list.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/pinctrl/consumer.h>
40 #include <linux/can.h>
41 #include <linux/can/dev.h>
42 #include <linux/can/error.h>
43 #include <linux/can/led.h>
47 /* Number of interface registers */
48 #define IF_ENUM_REG_LEN 11
49 #define C_CAN_IFACE(reg, iface) (C_CAN_IF1_##reg + (iface) * IF_ENUM_REG_LEN)
51 /* control extension register D_CAN specific */
52 #define CONTROL_EX_PDR BIT(8)
54 /* control register */
55 #define CONTROL_TEST BIT(7)
56 #define CONTROL_CCE BIT(6)
57 #define CONTROL_DISABLE_AR BIT(5)
58 #define CONTROL_ENABLE_AR (0 << 5)
59 #define CONTROL_EIE BIT(3)
60 #define CONTROL_SIE BIT(2)
61 #define CONTROL_IE BIT(1)
62 #define CONTROL_INIT BIT(0)
64 #define CONTROL_IRQMSK (CONTROL_EIE | CONTROL_IE | CONTROL_SIE)
67 #define TEST_RX BIT(7)
68 #define TEST_TX1 BIT(6)
69 #define TEST_TX2 BIT(5)
70 #define TEST_LBACK BIT(4)
71 #define TEST_SILENT BIT(3)
72 #define TEST_BASIC BIT(2)
75 #define STATUS_PDA BIT(10)
76 #define STATUS_BOFF BIT(7)
77 #define STATUS_EWARN BIT(6)
78 #define STATUS_EPASS BIT(5)
79 #define STATUS_RXOK BIT(4)
80 #define STATUS_TXOK BIT(3)
82 /* error counter register */
83 #define ERR_CNT_TEC_MASK 0xff
84 #define ERR_CNT_TEC_SHIFT 0
85 #define ERR_CNT_REC_SHIFT 8
86 #define ERR_CNT_REC_MASK (0x7f << ERR_CNT_REC_SHIFT)
87 #define ERR_CNT_RP_SHIFT 15
88 #define ERR_CNT_RP_MASK (0x1 << ERR_CNT_RP_SHIFT)
90 /* bit-timing register */
91 #define BTR_BRP_MASK 0x3f
92 #define BTR_BRP_SHIFT 0
93 #define BTR_SJW_SHIFT 6
94 #define BTR_SJW_MASK (0x3 << BTR_SJW_SHIFT)
95 #define BTR_TSEG1_SHIFT 8
96 #define BTR_TSEG1_MASK (0xf << BTR_TSEG1_SHIFT)
97 #define BTR_TSEG2_SHIFT 12
98 #define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT)
100 /* brp extension register */
101 #define BRP_EXT_BRPE_MASK 0x0f
102 #define BRP_EXT_BRPE_SHIFT 0
104 /* IFx command request */
105 #define IF_COMR_BUSY BIT(15)
107 /* IFx command mask */
108 #define IF_COMM_WR BIT(7)
109 #define IF_COMM_MASK BIT(6)
110 #define IF_COMM_ARB BIT(5)
111 #define IF_COMM_CONTROL BIT(4)
112 #define IF_COMM_CLR_INT_PND BIT(3)
113 #define IF_COMM_TXRQST BIT(2)
114 #define IF_COMM_CLR_NEWDAT IF_COMM_TXRQST
115 #define IF_COMM_DATAA BIT(1)
116 #define IF_COMM_DATAB BIT(0)
118 /* TX buffer setup */
119 #define IF_COMM_TX (IF_COMM_ARB | IF_COMM_CONTROL | \
121 IF_COMM_DATAA | IF_COMM_DATAB)
123 /* For the low buffers we clear the interrupt bit, but keep newdat */
124 #define IF_COMM_RCV_LOW (IF_COMM_MASK | IF_COMM_ARB | \
125 IF_COMM_CONTROL | IF_COMM_CLR_INT_PND | \
126 IF_COMM_DATAA | IF_COMM_DATAB)
128 /* For the high buffers we clear the interrupt bit and newdat */
129 #define IF_COMM_RCV_HIGH (IF_COMM_RCV_LOW | IF_COMM_CLR_NEWDAT)
132 /* Receive setup of message objects */
133 #define IF_COMM_RCV_SETUP (IF_COMM_MASK | IF_COMM_ARB | IF_COMM_CONTROL)
135 /* Invalidation of message objects */
136 #define IF_COMM_INVAL (IF_COMM_ARB | IF_COMM_CONTROL)
138 /* IFx arbitration */
139 #define IF_ARB_MSGVAL BIT(31)
140 #define IF_ARB_MSGXTD BIT(30)
141 #define IF_ARB_TRANSMIT BIT(29)
143 /* IFx message control */
144 #define IF_MCONT_NEWDAT BIT(15)
145 #define IF_MCONT_MSGLST BIT(14)
146 #define IF_MCONT_INTPND BIT(13)
147 #define IF_MCONT_UMASK BIT(12)
148 #define IF_MCONT_TXIE BIT(11)
149 #define IF_MCONT_RXIE BIT(10)
150 #define IF_MCONT_RMTEN BIT(9)
151 #define IF_MCONT_TXRQST BIT(8)
152 #define IF_MCONT_EOB BIT(7)
153 #define IF_MCONT_DLC_MASK 0xf
155 #define IF_MCONT_RCV (IF_MCONT_RXIE | IF_MCONT_UMASK)
156 #define IF_MCONT_RCV_EOB (IF_MCONT_RCV | IF_MCONT_EOB)
158 #define IF_MCONT_TX (IF_MCONT_TXIE | IF_MCONT_EOB)
161 * Use IF1 for RX and IF2 for TX
166 /* minimum timeout for checking BUSY status */
167 #define MIN_TIMEOUT_VALUE 6
169 /* Wait for ~1 sec for INIT bit */
170 #define INIT_WAIT_MS 1000
173 #define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM
175 /* c_can lec values */
176 enum c_can_lec_type {
185 LEC_MASK = LEC_UNUSED,
190 * Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported
192 enum c_can_bus_error_types {
199 static const struct can_bittiming_const c_can_bittiming_const = {
200 .name = KBUILD_MODNAME,
201 .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */
203 .tseg2_min = 1, /* Time segment 2 = phase_seg2 */
207 .brp_max = 1024, /* 6-bit BRP field + 4-bit BRPE field*/
211 static inline void c_can_pm_runtime_enable(const struct c_can_priv *priv)
214 pm_runtime_enable(priv->device);
217 static inline void c_can_pm_runtime_disable(const struct c_can_priv *priv)
220 pm_runtime_disable(priv->device);
223 static inline void c_can_pm_runtime_get_sync(const struct c_can_priv *priv)
226 pm_runtime_get_sync(priv->device);
229 static inline void c_can_pm_runtime_put_sync(const struct c_can_priv *priv)
232 pm_runtime_put_sync(priv->device);
235 static inline void c_can_reset_ram(const struct c_can_priv *priv, bool enable)
238 priv->raminit(priv, enable);
241 static void c_can_irq_control(struct c_can_priv *priv, bool enable)
243 u32 ctrl = priv->read_reg(priv, C_CAN_CTRL_REG) & ~CONTROL_IRQMSK;
246 ctrl |= CONTROL_IRQMSK;
248 priv->write_reg(priv, C_CAN_CTRL_REG, ctrl);
251 static void c_can_obj_update(struct net_device *dev, int iface, u32 cmd, u32 obj)
253 struct c_can_priv *priv = netdev_priv(dev);
254 int cnt, reg = C_CAN_IFACE(COMREQ_REG, iface);
256 priv->write_reg32(priv, reg, (cmd << 16) | obj);
258 for (cnt = MIN_TIMEOUT_VALUE; cnt; cnt--) {
259 if (!(priv->read_reg(priv, reg) & IF_COMR_BUSY))
263 netdev_err(dev, "Updating object timed out\n");
267 static inline void c_can_object_get(struct net_device *dev, int iface,
270 c_can_obj_update(dev, iface, cmd, obj);
273 static inline void c_can_object_put(struct net_device *dev, int iface,
276 c_can_obj_update(dev, iface, cmd | IF_COMM_WR, obj);
280 * Note: According to documentation clearing TXIE while MSGVAL is set
281 * is not allowed, but works nicely on C/DCAN. And that lowers the I/O
282 * load significantly.
284 static void c_can_inval_tx_object(struct net_device *dev, int iface, int obj)
286 struct c_can_priv *priv = netdev_priv(dev);
288 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), 0);
289 c_can_object_put(dev, iface, obj, IF_COMM_INVAL);
292 static void c_can_inval_msg_object(struct net_device *dev, int iface, int obj)
294 struct c_can_priv *priv = netdev_priv(dev);
296 priv->write_reg(priv, C_CAN_IFACE(ARB1_REG, iface), 0);
297 priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface), 0);
298 c_can_inval_tx_object(dev, iface, obj);
301 static void c_can_setup_tx_object(struct net_device *dev, int iface,
302 struct can_frame *frame, int idx)
304 struct c_can_priv *priv = netdev_priv(dev);
305 u16 ctrl = IF_MCONT_TX | frame->can_dlc;
306 bool rtr = frame->can_id & CAN_RTR_FLAG;
307 u32 arb = IF_ARB_MSGVAL;
310 if (frame->can_id & CAN_EFF_FLAG) {
311 arb |= frame->can_id & CAN_EFF_MASK;
312 arb |= IF_ARB_MSGXTD;
314 arb |= (frame->can_id & CAN_SFF_MASK) << 18;
318 arb |= IF_ARB_TRANSMIT;
321 * If we change the DIR bit, we need to invalidate the buffer
322 * first, i.e. clear the MSGVAL flag in the arbiter.
324 if (rtr != (bool)test_bit(idx, &priv->tx_dir)) {
325 u32 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
327 c_can_inval_msg_object(dev, iface, obj);
328 change_bit(idx, &priv->tx_dir);
331 priv->write_reg32(priv, C_CAN_IFACE(ARB1_REG, iface), arb);
333 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), ctrl);
335 for (i = 0; i < frame->can_dlc; i += 2) {
336 priv->write_reg(priv, C_CAN_IFACE(DATA1_REG, iface) + i / 2,
337 frame->data[i] | (frame->data[i + 1] << 8));
341 static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev,
346 for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_MSG_RX_LOW_LAST; i++)
347 c_can_object_get(dev, iface, i, IF_COMM_CLR_NEWDAT);
350 static int c_can_handle_lost_msg_obj(struct net_device *dev,
351 int iface, int objno, u32 ctrl)
353 struct net_device_stats *stats = &dev->stats;
354 struct c_can_priv *priv = netdev_priv(dev);
355 struct can_frame *frame;
358 ctrl &= ~(IF_MCONT_MSGLST | IF_MCONT_INTPND | IF_MCONT_NEWDAT);
359 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), ctrl);
360 c_can_object_put(dev, iface, objno, IF_COMM_CONTROL);
363 stats->rx_over_errors++;
365 /* create an error msg */
366 skb = alloc_can_err_skb(dev, &frame);
370 frame->can_id |= CAN_ERR_CRTL;
371 frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
373 netif_receive_skb(skb);
377 static int c_can_read_msg_object(struct net_device *dev, int iface, u32 ctrl)
379 struct net_device_stats *stats = &dev->stats;
380 struct c_can_priv *priv = netdev_priv(dev);
381 struct can_frame *frame;
385 skb = alloc_can_skb(dev, &frame);
391 frame->can_dlc = get_can_dlc(ctrl & 0x0F);
393 arb = priv->read_reg32(priv, C_CAN_IFACE(ARB1_REG, iface));
395 if (arb & IF_ARB_MSGXTD)
396 frame->can_id = (arb & CAN_EFF_MASK) | CAN_EFF_FLAG;
398 frame->can_id = (arb >> 18) & CAN_SFF_MASK;
400 if (arb & IF_ARB_TRANSMIT) {
401 frame->can_id |= CAN_RTR_FLAG;
403 int i, dreg = C_CAN_IFACE(DATA1_REG, iface);
405 for (i = 0; i < frame->can_dlc; i += 2, dreg ++) {
406 data = priv->read_reg(priv, dreg);
407 frame->data[i] = data;
408 frame->data[i + 1] = data >> 8;
413 stats->rx_bytes += frame->can_dlc;
415 netif_receive_skb(skb);
419 static void c_can_setup_receive_object(struct net_device *dev, int iface,
420 u32 obj, u32 mask, u32 id, u32 mcont)
422 struct c_can_priv *priv = netdev_priv(dev);
425 priv->write_reg32(priv, C_CAN_IFACE(MASK1_REG, iface), mask);
428 priv->write_reg32(priv, C_CAN_IFACE(ARB1_REG, iface), id);
430 priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), mcont);
431 c_can_object_put(dev, iface, obj, IF_COMM_RCV_SETUP);
434 static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
435 struct net_device *dev)
437 struct can_frame *frame = (struct can_frame *)skb->data;
438 struct c_can_priv *priv = netdev_priv(dev);
441 if (can_dropped_invalid_skb(dev, skb))
444 * This is not a FIFO. C/D_CAN sends out the buffers
445 * prioritized. The lowest buffer number wins.
447 idx = fls(atomic_read(&priv->tx_active));
448 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
450 /* If this is the last buffer, stop the xmit queue */
451 if (idx == C_CAN_MSG_OBJ_TX_NUM - 1)
452 netif_stop_queue(dev);
454 * Store the message in the interface so we can call
455 * can_put_echo_skb(). We must do this before we enable
456 * transmit as we might race against do_tx().
458 c_can_setup_tx_object(dev, IF_TX, frame, idx);
459 priv->dlc[idx] = frame->can_dlc;
460 can_put_echo_skb(skb, dev, idx);
462 /* Update the active bits */
463 atomic_add((1 << idx), &priv->tx_active);
464 /* Start transmission */
465 c_can_object_put(dev, IF_TX, obj, IF_COMM_TX);
470 static int c_can_wait_for_ctrl_init(struct net_device *dev,
471 struct c_can_priv *priv, u32 init)
475 while (init != (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_INIT)) {
477 if (retry++ > 1000) {
478 netdev_err(dev, "CCTRL: set CONTROL_INIT failed\n");
485 static int c_can_set_bittiming(struct net_device *dev)
487 unsigned int reg_btr, reg_brpe, ctrl_save;
488 u8 brp, brpe, sjw, tseg1, tseg2;
490 struct c_can_priv *priv = netdev_priv(dev);
491 const struct can_bittiming *bt = &priv->can.bittiming;
494 /* c_can provides a 6-bit brp and 4-bit brpe fields */
495 ten_bit_brp = bt->brp - 1;
496 brp = ten_bit_brp & BTR_BRP_MASK;
497 brpe = ten_bit_brp >> 6;
500 tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
501 tseg2 = bt->phase_seg2 - 1;
502 reg_btr = brp | (sjw << BTR_SJW_SHIFT) | (tseg1 << BTR_TSEG1_SHIFT) |
503 (tseg2 << BTR_TSEG2_SHIFT);
504 reg_brpe = brpe & BRP_EXT_BRPE_MASK;
507 "setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe);
509 ctrl_save = priv->read_reg(priv, C_CAN_CTRL_REG);
510 ctrl_save &= ~CONTROL_INIT;
511 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_CCE | CONTROL_INIT);
512 res = c_can_wait_for_ctrl_init(dev, priv, CONTROL_INIT);
516 priv->write_reg(priv, C_CAN_BTR_REG, reg_btr);
517 priv->write_reg(priv, C_CAN_BRPEXT_REG, reg_brpe);
518 priv->write_reg(priv, C_CAN_CTRL_REG, ctrl_save);
520 return c_can_wait_for_ctrl_init(dev, priv, 0);
524 * Configure C_CAN message objects for Tx and Rx purposes:
525 * C_CAN provides a total of 32 message objects that can be configured
526 * either for Tx or Rx purposes. Here the first 16 message objects are used as
527 * a reception FIFO. The end of reception FIFO is signified by the EoB bit
528 * being SET. The remaining 16 message objects are kept aside for Tx purposes.
529 * See user guide document for further details on configuring message
532 static void c_can_configure_msg_objects(struct net_device *dev)
536 /* first invalidate all message objects */
537 for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
538 c_can_inval_msg_object(dev, IF_RX, i);
540 /* setup receive message objects */
541 for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
542 c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV);
544 c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
549 * Configure C_CAN chip:
550 * - enable/disable auto-retransmission
551 * - set operating mode
552 * - configure message objects
554 static int c_can_chip_config(struct net_device *dev)
556 struct c_can_priv *priv = netdev_priv(dev);
558 /* enable automatic retransmission */
559 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR);
561 if ((priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) &&
562 (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)) {
563 /* loopback + silent mode : useful for hot self-test */
564 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
565 priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK | TEST_SILENT);
566 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
567 /* loopback mode : useful for self-test function */
568 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
569 priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK);
570 } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
571 /* silent mode : bus-monitoring mode */
572 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
573 priv->write_reg(priv, C_CAN_TEST_REG, TEST_SILENT);
576 /* configure message objects */
577 c_can_configure_msg_objects(dev);
579 /* set a `lec` value so that we can check for updates later */
580 priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED);
582 /* Clear all internal status */
583 atomic_set(&priv->tx_active, 0);
587 /* set bittiming params */
588 return c_can_set_bittiming(dev);
591 static int c_can_start(struct net_device *dev)
593 struct c_can_priv *priv = netdev_priv(dev);
596 /* basic c_can configuration */
597 err = c_can_chip_config(dev);
601 /* Setup the command for new messages */
602 priv->comm_rcv_high = priv->type != BOSCH_D_CAN ?
603 IF_COMM_RCV_LOW : IF_COMM_RCV_HIGH;
605 priv->can.state = CAN_STATE_ERROR_ACTIVE;
608 pinctrl_pm_select_default_state(dev->dev.parent);
612 static void c_can_stop(struct net_device *dev)
614 struct c_can_priv *priv = netdev_priv(dev);
616 c_can_irq_control(priv, false);
618 /* put ctrl to init on stop to end ongoing transmission */
619 priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_INIT);
621 /* deactivate pins */
622 pinctrl_pm_select_sleep_state(dev->dev.parent);
623 priv->can.state = CAN_STATE_STOPPED;
626 static int c_can_set_mode(struct net_device *dev, enum can_mode mode)
628 struct c_can_priv *priv = netdev_priv(dev);
633 err = c_can_start(dev);
636 netif_wake_queue(dev);
637 c_can_irq_control(priv, true);
646 static int __c_can_get_berr_counter(const struct net_device *dev,
647 struct can_berr_counter *bec)
649 unsigned int reg_err_counter;
650 struct c_can_priv *priv = netdev_priv(dev);
652 reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG);
653 bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >>
655 bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK;
660 static int c_can_get_berr_counter(const struct net_device *dev,
661 struct can_berr_counter *bec)
663 struct c_can_priv *priv = netdev_priv(dev);
666 c_can_pm_runtime_get_sync(priv);
667 err = __c_can_get_berr_counter(dev, bec);
668 c_can_pm_runtime_put_sync(priv);
673 static void c_can_do_tx(struct net_device *dev)
675 struct c_can_priv *priv = netdev_priv(dev);
676 struct net_device_stats *stats = &dev->stats;
677 u32 idx, obj, pkts = 0, bytes = 0, pend, clr;
679 clr = pend = priv->read_reg(priv, C_CAN_INTPND2_REG);
681 while ((idx = ffs(pend))) {
684 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
685 c_can_inval_tx_object(dev, IF_RX, obj);
686 can_get_echo_skb(dev, idx);
687 bytes += priv->dlc[idx];
691 /* Clear the bits in the tx_active mask */
692 atomic_sub(clr, &priv->tx_active);
694 if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))
695 netif_wake_queue(dev);
698 stats->tx_bytes += bytes;
699 stats->tx_packets += pkts;
700 can_led_event(dev, CAN_LED_EVENT_TX);
705 * If we have a gap in the pending bits, that means we either
706 * raced with the hardware or failed to readout all upper
707 * objects in the last run due to quota limit.
709 static u32 c_can_adjust_pending(u32 pend)
713 if (pend == RECEIVE_OBJECT_BITS)
717 * If the last set bit is larger than the number of pending
718 * bits we have a gap.
720 weight = hweight32(pend);
723 /* If the bits are linear, nothing to do */
728 * Find the first set bit after the gap. We walk backwards
729 * from the last set bit.
731 for (lasts--; pend & (1 << (lasts - 1)); lasts--);
733 return pend & ~((1 << lasts) - 1);
736 static inline void c_can_rx_object_get(struct net_device *dev,
737 struct c_can_priv *priv, u32 obj)
739 c_can_object_get(dev, IF_RX, obj, priv->comm_rcv_high);
742 static inline void c_can_rx_finalize(struct net_device *dev,
743 struct c_can_priv *priv, u32 obj)
745 if (priv->type != BOSCH_D_CAN)
746 c_can_object_get(dev, IF_RX, obj, IF_COMM_CLR_NEWDAT);
749 static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv,
752 u32 pkts = 0, ctrl, obj;
754 while ((obj = ffs(pend)) && quota > 0) {
755 pend &= ~BIT(obj - 1);
757 c_can_rx_object_get(dev, priv, obj);
758 ctrl = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, IF_RX));
760 if (ctrl & IF_MCONT_MSGLST) {
761 int n = c_can_handle_lost_msg_obj(dev, IF_RX, obj, ctrl);
769 * This really should not happen, but this covers some
770 * odd HW behaviour. Do not remove that unless you
771 * want to brick your machine.
773 if (!(ctrl & IF_MCONT_NEWDAT))
776 /* read the data from the message object */
777 c_can_read_msg_object(dev, IF_RX, ctrl);
779 c_can_rx_finalize(dev, priv, obj);
788 static inline u32 c_can_get_pending(struct c_can_priv *priv)
790 u32 pend = priv->read_reg(priv, C_CAN_NEWDAT1_REG);
796 * theory of operation:
798 * c_can core saves a received CAN message into the first free message
799 * object it finds free (starting with the lowest). Bits NEWDAT and
800 * INTPND are set for this message object indicating that a new message
801 * has arrived. To work-around this issue, we keep two groups of message
802 * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT.
804 * We clear the newdat bit right away.
806 * This can result in packet reordering when the readout is slow.
808 static int c_can_do_rx_poll(struct net_device *dev, int quota)
810 struct c_can_priv *priv = netdev_priv(dev);
811 u32 pkts = 0, pend = 0, toread, n;
814 * It is faster to read only one 16bit register. This is only possible
815 * for a maximum number of 16 objects.
817 BUILD_BUG_ON_MSG(C_CAN_MSG_OBJ_RX_LAST > 16,
818 "Implementation does not support more message objects than 16");
822 pend = c_can_get_pending(priv);
826 * If the pending field has a gap, handle the
827 * bits above the gap first.
829 toread = c_can_adjust_pending(pend);
833 /* Remove the bits from pend */
835 /* Read the objects */
836 n = c_can_read_objects(dev, priv, toread, quota);
842 can_led_event(dev, CAN_LED_EVENT_RX);
847 static int c_can_handle_state_change(struct net_device *dev,
848 enum c_can_bus_error_types error_type)
850 unsigned int reg_err_counter;
851 unsigned int rx_err_passive;
852 struct c_can_priv *priv = netdev_priv(dev);
853 struct net_device_stats *stats = &dev->stats;
854 struct can_frame *cf;
856 struct can_berr_counter bec;
858 switch (error_type) {
859 case C_CAN_ERROR_WARNING:
860 /* error warning state */
861 priv->can.can_stats.error_warning++;
862 priv->can.state = CAN_STATE_ERROR_WARNING;
864 case C_CAN_ERROR_PASSIVE:
865 /* error passive state */
866 priv->can.can_stats.error_passive++;
867 priv->can.state = CAN_STATE_ERROR_PASSIVE;
871 priv->can.state = CAN_STATE_BUS_OFF;
872 priv->can.can_stats.bus_off++;
878 /* propagate the error condition to the CAN stack */
879 skb = alloc_can_err_skb(dev, &cf);
883 __c_can_get_berr_counter(dev, &bec);
884 reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG);
885 rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >>
888 switch (error_type) {
889 case C_CAN_ERROR_WARNING:
890 /* error warning state */
891 cf->can_id |= CAN_ERR_CRTL;
892 cf->data[1] = (bec.txerr > bec.rxerr) ?
893 CAN_ERR_CRTL_TX_WARNING :
894 CAN_ERR_CRTL_RX_WARNING;
895 cf->data[6] = bec.txerr;
896 cf->data[7] = bec.rxerr;
899 case C_CAN_ERROR_PASSIVE:
900 /* error passive state */
901 cf->can_id |= CAN_ERR_CRTL;
903 cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
905 cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
907 cf->data[6] = bec.txerr;
908 cf->data[7] = bec.rxerr;
912 cf->can_id |= CAN_ERR_BUSOFF;
920 stats->rx_bytes += cf->can_dlc;
921 netif_receive_skb(skb);
926 static int c_can_handle_bus_err(struct net_device *dev,
927 enum c_can_lec_type lec_type)
929 struct c_can_priv *priv = netdev_priv(dev);
930 struct net_device_stats *stats = &dev->stats;
931 struct can_frame *cf;
935 * early exit if no lec update or no error.
936 * no lec update means that no CAN bus event has been detected
937 * since CPU wrote 0x7 value to status reg.
939 if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
942 if (!(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
945 /* common for all type of bus errors */
946 priv->can.can_stats.bus_error++;
949 /* propagate the error condition to the CAN stack */
950 skb = alloc_can_err_skb(dev, &cf);
955 * check for 'last error code' which tells us the
956 * type of the last error to occur on the CAN bus
958 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
959 cf->data[2] |= CAN_ERR_PROT_UNSPEC;
962 case LEC_STUFF_ERROR:
963 netdev_dbg(dev, "stuff error\n");
964 cf->data[2] |= CAN_ERR_PROT_STUFF;
967 netdev_dbg(dev, "form error\n");
968 cf->data[2] |= CAN_ERR_PROT_FORM;
971 netdev_dbg(dev, "ack error\n");
972 cf->data[3] |= (CAN_ERR_PROT_LOC_ACK |
973 CAN_ERR_PROT_LOC_ACK_DEL);
976 netdev_dbg(dev, "bit1 error\n");
977 cf->data[2] |= CAN_ERR_PROT_BIT1;
980 netdev_dbg(dev, "bit0 error\n");
981 cf->data[2] |= CAN_ERR_PROT_BIT0;
984 netdev_dbg(dev, "CRC error\n");
985 cf->data[3] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
986 CAN_ERR_PROT_LOC_CRC_DEL);
993 stats->rx_bytes += cf->can_dlc;
994 netif_receive_skb(skb);
998 static int c_can_poll(struct napi_struct *napi, int quota)
1000 struct net_device *dev = napi->dev;
1001 struct c_can_priv *priv = netdev_priv(dev);
1002 u16 curr, last = priv->last_status;
1005 priv->last_status = curr = priv->read_reg(priv, C_CAN_STS_REG);
1006 /* Ack status on C_CAN. D_CAN is self clearing */
1007 if (priv->type != BOSCH_D_CAN)
1008 priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED);
1010 /* handle state changes */
1011 if ((curr & STATUS_EWARN) && (!(last & STATUS_EWARN))) {
1012 netdev_dbg(dev, "entered error warning state\n");
1013 work_done += c_can_handle_state_change(dev, C_CAN_ERROR_WARNING);
1016 if ((curr & STATUS_EPASS) && (!(last & STATUS_EPASS))) {
1017 netdev_dbg(dev, "entered error passive state\n");
1018 work_done += c_can_handle_state_change(dev, C_CAN_ERROR_PASSIVE);
1021 if ((curr & STATUS_BOFF) && (!(last & STATUS_BOFF))) {
1022 netdev_dbg(dev, "entered bus off state\n");
1023 work_done += c_can_handle_state_change(dev, C_CAN_BUS_OFF);
1027 /* handle bus recovery events */
1028 if ((!(curr & STATUS_BOFF)) && (last & STATUS_BOFF)) {
1029 netdev_dbg(dev, "left bus off state\n");
1030 priv->can.state = CAN_STATE_ERROR_ACTIVE;
1032 if ((!(curr & STATUS_EPASS)) && (last & STATUS_EPASS)) {
1033 netdev_dbg(dev, "left error passive state\n");
1034 priv->can.state = CAN_STATE_ERROR_ACTIVE;
1037 /* handle lec errors on the bus */
1038 work_done += c_can_handle_bus_err(dev, curr & LEC_MASK);
1040 /* Handle Tx/Rx events. We do this unconditionally */
1041 work_done += c_can_do_rx_poll(dev, (quota - work_done));
1045 if (work_done < quota) {
1046 napi_complete(napi);
1047 /* enable all IRQs if we are not in bus off state */
1048 if (priv->can.state != CAN_STATE_BUS_OFF)
1049 c_can_irq_control(priv, true);
1055 static irqreturn_t c_can_isr(int irq, void *dev_id)
1057 struct net_device *dev = (struct net_device *)dev_id;
1058 struct c_can_priv *priv = netdev_priv(dev);
1060 if (!priv->read_reg(priv, C_CAN_INT_REG))
1063 /* disable all interrupts and schedule the NAPI */
1064 c_can_irq_control(priv, false);
1065 napi_schedule(&priv->napi);
1070 static int c_can_open(struct net_device *dev)
1073 struct c_can_priv *priv = netdev_priv(dev);
1075 c_can_pm_runtime_get_sync(priv);
1076 c_can_reset_ram(priv, true);
1078 /* open the can device */
1079 err = open_candev(dev);
1081 netdev_err(dev, "failed to open can device\n");
1082 goto exit_open_fail;
1085 /* register interrupt handler */
1086 err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name,
1089 netdev_err(dev, "failed to request interrupt\n");
1093 /* start the c_can controller */
1094 err = c_can_start(dev);
1096 goto exit_start_fail;
1098 can_led_event(dev, CAN_LED_EVENT_OPEN);
1100 napi_enable(&priv->napi);
1101 /* enable status change, error and module interrupts */
1102 c_can_irq_control(priv, true);
1103 netif_start_queue(dev);
1108 free_irq(dev->irq, dev);
1112 c_can_reset_ram(priv, false);
1113 c_can_pm_runtime_put_sync(priv);
1117 static int c_can_close(struct net_device *dev)
1119 struct c_can_priv *priv = netdev_priv(dev);
1121 netif_stop_queue(dev);
1122 napi_disable(&priv->napi);
1124 free_irq(dev->irq, dev);
1127 c_can_reset_ram(priv, false);
1128 c_can_pm_runtime_put_sync(priv);
1130 can_led_event(dev, CAN_LED_EVENT_STOP);
1135 struct net_device *alloc_c_can_dev(void)
1137 struct net_device *dev;
1138 struct c_can_priv *priv;
1140 dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
1144 priv = netdev_priv(dev);
1145 netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
1148 priv->can.bittiming_const = &c_can_bittiming_const;
1149 priv->can.do_set_mode = c_can_set_mode;
1150 priv->can.do_get_berr_counter = c_can_get_berr_counter;
1151 priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
1152 CAN_CTRLMODE_LISTENONLY |
1153 CAN_CTRLMODE_BERR_REPORTING;
1157 EXPORT_SYMBOL_GPL(alloc_c_can_dev);
1160 int c_can_power_down(struct net_device *dev)
1163 unsigned long time_out;
1164 struct c_can_priv *priv = netdev_priv(dev);
1166 if (!(dev->flags & IFF_UP))
1169 WARN_ON(priv->type != BOSCH_D_CAN);
1171 /* set PDR value so the device goes to power down mode */
1172 val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
1173 val |= CONTROL_EX_PDR;
1174 priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
1176 /* Wait for the PDA bit to get set */
1177 time_out = jiffies + msecs_to_jiffies(INIT_WAIT_MS);
1178 while (!(priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
1179 time_after(time_out, jiffies))
1182 if (time_after(jiffies, time_out))
1187 c_can_reset_ram(priv, false);
1188 c_can_pm_runtime_put_sync(priv);
1192 EXPORT_SYMBOL_GPL(c_can_power_down);
1194 int c_can_power_up(struct net_device *dev)
1197 unsigned long time_out;
1198 struct c_can_priv *priv = netdev_priv(dev);
1201 if (!(dev->flags & IFF_UP))
1204 WARN_ON(priv->type != BOSCH_D_CAN);
1206 c_can_pm_runtime_get_sync(priv);
1207 c_can_reset_ram(priv, true);
1209 /* Clear PDR and INIT bits */
1210 val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
1211 val &= ~CONTROL_EX_PDR;
1212 priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
1213 val = priv->read_reg(priv, C_CAN_CTRL_REG);
1214 val &= ~CONTROL_INIT;
1215 priv->write_reg(priv, C_CAN_CTRL_REG, val);
1217 /* Wait for the PDA bit to get clear */
1218 time_out = jiffies + msecs_to_jiffies(INIT_WAIT_MS);
1219 while ((priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
1220 time_after(time_out, jiffies))
1223 if (time_after(jiffies, time_out))
1226 ret = c_can_start(dev);
1228 c_can_irq_control(priv, true);
1232 EXPORT_SYMBOL_GPL(c_can_power_up);
1235 void free_c_can_dev(struct net_device *dev)
1237 struct c_can_priv *priv = netdev_priv(dev);
1239 netif_napi_del(&priv->napi);
1242 EXPORT_SYMBOL_GPL(free_c_can_dev);
1244 static const struct net_device_ops c_can_netdev_ops = {
1245 .ndo_open = c_can_open,
1246 .ndo_stop = c_can_close,
1247 .ndo_start_xmit = c_can_start_xmit,
1248 .ndo_change_mtu = can_change_mtu,
1251 int register_c_can_dev(struct net_device *dev)
1253 struct c_can_priv *priv = netdev_priv(dev);
1256 /* Deactivate pins to prevent DRA7 DCAN IP from being
1257 * stuck in transition when module is disabled.
1258 * Pins are activated in c_can_start() and deactivated
1261 pinctrl_pm_select_sleep_state(dev->dev.parent);
1263 c_can_pm_runtime_enable(priv);
1265 dev->flags |= IFF_ECHO; /* we support local echo */
1266 dev->netdev_ops = &c_can_netdev_ops;
1268 err = register_candev(dev);
1270 c_can_pm_runtime_disable(priv);
1272 devm_can_led_init(dev);
1276 EXPORT_SYMBOL_GPL(register_c_can_dev);
1278 void unregister_c_can_dev(struct net_device *dev)
1280 struct c_can_priv *priv = netdev_priv(dev);
1282 unregister_candev(dev);
1284 c_can_pm_runtime_disable(priv);
1286 EXPORT_SYMBOL_GPL(unregister_c_can_dev);
1288 MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
1289 MODULE_LICENSE("GPL v2");
1290 MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");