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linux/drivers/net/can/c_can/c_can.c

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/*
* CAN bus driver for Bosch C_CAN controller
*
* Copyright (C) 2010 ST Microelectronics
* Bhupesh Sharma <bhupesh.sharma@st.com>
*
* Borrowed heavily from the C_CAN driver originally written by:
* Copyright (C) 2007
* - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
* - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
*
* TX and RX NAPI implementation has been borrowed from at91 CAN driver
* written by:
* Copyright
* (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
* (C) 2008, 2009 by Marc Kleine-Budde <kernel@pengutronix.de>
*
* Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
* Bosch C_CAN user manual can be obtained from:
* http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
* users_manual_c_can.pdf
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
#include "c_can.h"
/* control register */
#define CONTROL_TEST BIT(7)
#define CONTROL_CCE BIT(6)
#define CONTROL_DISABLE_AR BIT(5)
#define CONTROL_ENABLE_AR (0 << 5)
#define CONTROL_EIE BIT(3)
#define CONTROL_SIE BIT(2)
#define CONTROL_IE BIT(1)
#define CONTROL_INIT BIT(0)
/* test register */
#define TEST_RX BIT(7)
#define TEST_TX1 BIT(6)
#define TEST_TX2 BIT(5)
#define TEST_LBACK BIT(4)
#define TEST_SILENT BIT(3)
#define TEST_BASIC BIT(2)
/* status register */
#define STATUS_BOFF BIT(7)
#define STATUS_EWARN BIT(6)
#define STATUS_EPASS BIT(5)
#define STATUS_RXOK BIT(4)
#define STATUS_TXOK BIT(3)
/* error counter register */
#define ERR_CNT_TEC_MASK 0xff
#define ERR_CNT_TEC_SHIFT 0
#define ERR_CNT_REC_SHIFT 8
#define ERR_CNT_REC_MASK (0x7f << ERR_CNT_REC_SHIFT)
#define ERR_CNT_RP_SHIFT 15
#define ERR_CNT_RP_MASK (0x1 << ERR_CNT_RP_SHIFT)
/* bit-timing register */
#define BTR_BRP_MASK 0x3f
#define BTR_BRP_SHIFT 0
#define BTR_SJW_SHIFT 6
#define BTR_SJW_MASK (0x3 << BTR_SJW_SHIFT)
#define BTR_TSEG1_SHIFT 8
#define BTR_TSEG1_MASK (0xf << BTR_TSEG1_SHIFT)
#define BTR_TSEG2_SHIFT 12
#define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT)
/* brp extension register */
#define BRP_EXT_BRPE_MASK 0x0f
#define BRP_EXT_BRPE_SHIFT 0
/* IFx command request */
#define IF_COMR_BUSY BIT(15)
/* IFx command mask */
#define IF_COMM_WR BIT(7)
#define IF_COMM_MASK BIT(6)
#define IF_COMM_ARB BIT(5)
#define IF_COMM_CONTROL BIT(4)
#define IF_COMM_CLR_INT_PND BIT(3)
#define IF_COMM_TXRQST BIT(2)
#define IF_COMM_DATAA BIT(1)
#define IF_COMM_DATAB BIT(0)
#define IF_COMM_ALL (IF_COMM_MASK | IF_COMM_ARB | \
IF_COMM_CONTROL | IF_COMM_TXRQST | \
IF_COMM_DATAA | IF_COMM_DATAB)
/* IFx arbitration */
#define IF_ARB_MSGVAL BIT(15)
#define IF_ARB_MSGXTD BIT(14)
#define IF_ARB_TRANSMIT BIT(13)
/* IFx message control */
#define IF_MCONT_NEWDAT BIT(15)
#define IF_MCONT_MSGLST BIT(14)
#define IF_MCONT_CLR_MSGLST (0 << 14)
#define IF_MCONT_INTPND BIT(13)
#define IF_MCONT_UMASK BIT(12)
#define IF_MCONT_TXIE BIT(11)
#define IF_MCONT_RXIE BIT(10)
#define IF_MCONT_RMTEN BIT(9)
#define IF_MCONT_TXRQST BIT(8)
#define IF_MCONT_EOB BIT(7)
#define IF_MCONT_DLC_MASK 0xf
/*
* IFx register masks:
* allow easy operation on 16-bit registers when the
* argument is 32-bit instead
*/
#define IFX_WRITE_LOW_16BIT(x) ((x) & 0xFFFF)
#define IFX_WRITE_HIGH_16BIT(x) (((x) & 0xFFFF0000) >> 16)
/* message object split */
#define C_CAN_NO_OF_OBJECTS 32
#define C_CAN_MSG_OBJ_RX_NUM 16
#define C_CAN_MSG_OBJ_TX_NUM 16
#define C_CAN_MSG_OBJ_RX_FIRST 1
#define C_CAN_MSG_OBJ_RX_LAST (C_CAN_MSG_OBJ_RX_FIRST + \
C_CAN_MSG_OBJ_RX_NUM - 1)
#define C_CAN_MSG_OBJ_TX_FIRST (C_CAN_MSG_OBJ_RX_LAST + 1)
#define C_CAN_MSG_OBJ_TX_LAST (C_CAN_MSG_OBJ_TX_FIRST + \
C_CAN_MSG_OBJ_TX_NUM - 1)
#define C_CAN_MSG_OBJ_RX_SPLIT 9
#define C_CAN_MSG_RX_LOW_LAST (C_CAN_MSG_OBJ_RX_SPLIT - 1)
#define C_CAN_NEXT_MSG_OBJ_MASK (C_CAN_MSG_OBJ_TX_NUM - 1)
#define RECEIVE_OBJECT_BITS 0x0000ffff
/* status interrupt */
#define STATUS_INTERRUPT 0x8000
/* global interrupt masks */
#define ENABLE_ALL_INTERRUPTS 1
#define DISABLE_ALL_INTERRUPTS 0
/* minimum timeout for checking BUSY status */
#define MIN_TIMEOUT_VALUE 6
/* napi related */
#define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM
/* c_can lec values */
enum c_can_lec_type {
LEC_NO_ERROR = 0,
LEC_STUFF_ERROR,
LEC_FORM_ERROR,
LEC_ACK_ERROR,
LEC_BIT1_ERROR,
LEC_BIT0_ERROR,
LEC_CRC_ERROR,
LEC_UNUSED,
};
/*
* c_can error types:
* Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported
*/
enum c_can_bus_error_types {
C_CAN_NO_ERROR = 0,
C_CAN_BUS_OFF,
C_CAN_ERROR_WARNING,
C_CAN_ERROR_PASSIVE,
};
static struct can_bittiming_const c_can_bittiming_const = {
.name = KBUILD_MODNAME,
.tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */
.tseg1_max = 16,
.tseg2_min = 1, /* Time segment 2 = phase_seg2 */
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 1024, /* 6-bit BRP field + 4-bit BRPE field*/
.brp_inc = 1,
};
static inline int get_tx_next_msg_obj(const struct c_can_priv *priv)
{
return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) +
C_CAN_MSG_OBJ_TX_FIRST;
}
static inline int get_tx_echo_msg_obj(const struct c_can_priv *priv)
{
return (priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) +
C_CAN_MSG_OBJ_TX_FIRST;
}
static u32 c_can_read_reg32(struct c_can_priv *priv, void *reg)
{
u32 val = priv->read_reg(priv, reg);
val |= ((u32) priv->read_reg(priv, reg + 2)) << 16;
return val;
}
static void c_can_enable_all_interrupts(struct c_can_priv *priv,
int enable)
{
unsigned int cntrl_save = priv->read_reg(priv,
&priv->regs->control);
if (enable)
cntrl_save |= (CONTROL_SIE | CONTROL_EIE | CONTROL_IE);
else
cntrl_save &= ~(CONTROL_EIE | CONTROL_IE | CONTROL_SIE);
priv->write_reg(priv, &priv->regs->control, cntrl_save);
}
static inline int c_can_msg_obj_is_busy(struct c_can_priv *priv, int iface)
{
int count = MIN_TIMEOUT_VALUE;
while (count && priv->read_reg(priv,
&priv->regs->ifregs[iface].com_req) &
IF_COMR_BUSY) {
count--;
udelay(1);
}
if (!count)
return 1;
return 0;
}
static inline void c_can_object_get(struct net_device *dev,
int iface, int objno, int mask)
{
struct c_can_priv *priv = netdev_priv(dev);
/*
* As per specs, after writting the message object number in the
* IF command request register the transfer b/w interface
* register and message RAM must be complete in 6 CAN-CLK
* period.
*/
priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask,
IFX_WRITE_LOW_16BIT(mask));
priv->write_reg(priv, &priv->regs->ifregs[iface].com_req,
IFX_WRITE_LOW_16BIT(objno));
if (c_can_msg_obj_is_busy(priv, iface))
netdev_err(dev, "timed out in object get\n");
}
static inline void c_can_object_put(struct net_device *dev,
int iface, int objno, int mask)
{
struct c_can_priv *priv = netdev_priv(dev);
/*
* As per specs, after writting the message object number in the
* IF command request register the transfer b/w interface
* register and message RAM must be complete in 6 CAN-CLK
* period.
*/
priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask,
(IF_COMM_WR | IFX_WRITE_LOW_16BIT(mask)));
priv->write_reg(priv, &priv->regs->ifregs[iface].com_req,
IFX_WRITE_LOW_16BIT(objno));
if (c_can_msg_obj_is_busy(priv, iface))
netdev_err(dev, "timed out in object put\n");
}
static void c_can_write_msg_object(struct net_device *dev,
int iface, struct can_frame *frame, int objno)
{
int i;
u16 flags = 0;
unsigned int id;
struct c_can_priv *priv = netdev_priv(dev);
if (!(frame->can_id & CAN_RTR_FLAG))
flags |= IF_ARB_TRANSMIT;
if (frame->can_id & CAN_EFF_FLAG) {
id = frame->can_id & CAN_EFF_MASK;
flags |= IF_ARB_MSGXTD;
} else
id = ((frame->can_id & CAN_SFF_MASK) << 18);
flags |= IF_ARB_MSGVAL;
priv->write_reg(priv, &priv->regs->ifregs[iface].arb1,
IFX_WRITE_LOW_16BIT(id));
priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, flags |
IFX_WRITE_HIGH_16BIT(id));
for (i = 0; i < frame->can_dlc; i += 2) {
priv->write_reg(priv, &priv->regs->ifregs[iface].data[i / 2],
frame->data[i] | (frame->data[i + 1] << 8));
}
/* enable interrupt for this message object */
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
IF_MCONT_TXIE | IF_MCONT_TXRQST | IF_MCONT_EOB |
frame->can_dlc);
c_can_object_put(dev, iface, objno, IF_COMM_ALL);
}
static inline void c_can_mark_rx_msg_obj(struct net_device *dev,
int iface, int ctrl_mask,
int obj)
{
struct c_can_priv *priv = netdev_priv(dev);
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
ctrl_mask & ~(IF_MCONT_MSGLST | IF_MCONT_INTPND));
c_can_object_put(dev, iface, obj, IF_COMM_CONTROL);
}
static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev,
int iface,
int ctrl_mask)
{
int i;
struct c_can_priv *priv = netdev_priv(dev);
for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_MSG_RX_LOW_LAST; i++) {
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
ctrl_mask & ~(IF_MCONT_MSGLST |
IF_MCONT_INTPND | IF_MCONT_NEWDAT));
c_can_object_put(dev, iface, i, IF_COMM_CONTROL);
}
}
static inline void c_can_activate_rx_msg_obj(struct net_device *dev,
int iface, int ctrl_mask,
int obj)
{
struct c_can_priv *priv = netdev_priv(dev);
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
ctrl_mask & ~(IF_MCONT_MSGLST |
IF_MCONT_INTPND | IF_MCONT_NEWDAT));
c_can_object_put(dev, iface, obj, IF_COMM_CONTROL);
}
static void c_can_handle_lost_msg_obj(struct net_device *dev,
int iface, int objno)
{
struct c_can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
struct can_frame *frame;
netdev_err(dev, "msg lost in buffer %d\n", objno);
c_can_object_get(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST);
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
IF_MCONT_CLR_MSGLST);
c_can_object_put(dev, 0, objno, IF_COMM_CONTROL);
/* create an error msg */
skb = alloc_can_err_skb(dev, &frame);
if (unlikely(!skb))
return;
frame->can_id |= CAN_ERR_CRTL;
frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
stats->rx_errors++;
stats->rx_over_errors++;
netif_receive_skb(skb);
}
static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl)
{
u16 flags, data;
int i;
unsigned int val;
struct c_can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
struct can_frame *frame;
skb = alloc_can_skb(dev, &frame);
if (!skb) {
stats->rx_dropped++;
return -ENOMEM;
}
frame->can_dlc = get_can_dlc(ctrl & 0x0F);
flags = priv->read_reg(priv, &priv->regs->ifregs[iface].arb2);
val = priv->read_reg(priv, &priv->regs->ifregs[iface].arb1) |
(flags << 16);
if (flags & IF_ARB_MSGXTD)
frame->can_id = (val & CAN_EFF_MASK) | CAN_EFF_FLAG;
else
frame->can_id = (val >> 18) & CAN_SFF_MASK;
if (flags & IF_ARB_TRANSMIT)
frame->can_id |= CAN_RTR_FLAG;
else {
for (i = 0; i < frame->can_dlc; i += 2) {
data = priv->read_reg(priv,
&priv->regs->ifregs[iface].data[i / 2]);
frame->data[i] = data;
frame->data[i + 1] = data >> 8;
}
}
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += frame->can_dlc;
return 0;
}
static void c_can_setup_receive_object(struct net_device *dev, int iface,
int objno, unsigned int mask,
unsigned int id, unsigned int mcont)
{
struct c_can_priv *priv = netdev_priv(dev);
priv->write_reg(priv, &priv->regs->ifregs[iface].mask1,
IFX_WRITE_LOW_16BIT(mask));
priv->write_reg(priv, &priv->regs->ifregs[iface].mask2,
IFX_WRITE_HIGH_16BIT(mask));
priv->write_reg(priv, &priv->regs->ifregs[iface].arb1,
IFX_WRITE_LOW_16BIT(id));
priv->write_reg(priv, &priv->regs->ifregs[iface].arb2,
(IF_ARB_MSGVAL | IFX_WRITE_HIGH_16BIT(id)));
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, mcont);
c_can_object_put(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST);
netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno,
c_can_read_reg32(priv, &priv->regs->msgval1));
}
static void c_can_inval_msg_object(struct net_device *dev, int iface, int objno)
{
struct c_can_priv *priv = netdev_priv(dev);
priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, 0);
priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, 0);
priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 0);
c_can_object_put(dev, iface, objno, IF_COMM_ARB | IF_COMM_CONTROL);
netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno,
c_can_read_reg32(priv, &priv->regs->msgval1));
}
static inline int c_can_is_next_tx_obj_busy(struct c_can_priv *priv, int objno)
{
int val = c_can_read_reg32(priv, &priv->regs->txrqst1);
/*
* as transmission request register's bit n-1 corresponds to
* message object n, we need to handle the same properly.
*/
if (val & (1 << (objno - 1)))
return 1;
return 0;
}
static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
u32 msg_obj_no;
struct c_can_priv *priv = netdev_priv(dev);
struct can_frame *frame = (struct can_frame *)skb->data;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
msg_obj_no = get_tx_next_msg_obj(priv);
/* prepare message object for transmission */
c_can_write_msg_object(dev, 0, frame, msg_obj_no);
can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
/*
* we have to stop the queue in case of a wrap around or
* if the next TX message object is still in use
*/
priv->tx_next++;
if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) ||
(priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0)
netif_stop_queue(dev);
return NETDEV_TX_OK;
}
static int c_can_set_bittiming(struct net_device *dev)
{
unsigned int reg_btr, reg_brpe, ctrl_save;
u8 brp, brpe, sjw, tseg1, tseg2;
u32 ten_bit_brp;
struct c_can_priv *priv = netdev_priv(dev);
const struct can_bittiming *bt = &priv->can.bittiming;
/* c_can provides a 6-bit brp and 4-bit brpe fields */
ten_bit_brp = bt->brp - 1;
brp = ten_bit_brp & BTR_BRP_MASK;
brpe = ten_bit_brp >> 6;
sjw = bt->sjw - 1;
tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
tseg2 = bt->phase_seg2 - 1;
reg_btr = brp | (sjw << BTR_SJW_SHIFT) | (tseg1 << BTR_TSEG1_SHIFT) |
(tseg2 << BTR_TSEG2_SHIFT);
reg_brpe = brpe & BRP_EXT_BRPE_MASK;
netdev_info(dev,
"setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe);
ctrl_save = priv->read_reg(priv, &priv->regs->control);
priv->write_reg(priv, &priv->regs->control,
ctrl_save | CONTROL_CCE | CONTROL_INIT);
priv->write_reg(priv, &priv->regs->btr, reg_btr);
priv->write_reg(priv, &priv->regs->brp_ext, reg_brpe);
priv->write_reg(priv, &priv->regs->control, ctrl_save);
return 0;
}
/*
* Configure C_CAN message objects for Tx and Rx purposes:
* C_CAN provides a total of 32 message objects that can be configured
* either for Tx or Rx purposes. Here the first 16 message objects are used as
* a reception FIFO. The end of reception FIFO is signified by the EoB bit
* being SET. The remaining 16 message objects are kept aside for Tx purposes.
* See user guide document for further details on configuring message
* objects.
*/
static void c_can_configure_msg_objects(struct net_device *dev)
{
int i;
/* first invalidate all message objects */
for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
c_can_inval_msg_object(dev, 0, i);
/* setup receive message objects */
for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
c_can_setup_receive_object(dev, 0, i, 0, 0,
(IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB);
c_can_setup_receive_object(dev, 0, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK);
}
/*
* Configure C_CAN chip:
* - enable/disable auto-retransmission
* - set operating mode
* - configure message objects
*/
static void c_can_chip_config(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
/* enable automatic retransmission */
priv->write_reg(priv, &priv->regs->control,
CONTROL_ENABLE_AR);
if (priv->can.ctrlmode & (CAN_CTRLMODE_LISTENONLY &
CAN_CTRLMODE_LOOPBACK)) {
/* loopback + silent mode : useful for hot self-test */
priv->write_reg(priv, &priv->regs->control, CONTROL_EIE |
CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
priv->write_reg(priv, &priv->regs->test,
TEST_LBACK | TEST_SILENT);
} else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
/* loopback mode : useful for self-test function */
priv->write_reg(priv, &priv->regs->control, CONTROL_EIE |
CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
priv->write_reg(priv, &priv->regs->test, TEST_LBACK);
} else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
/* silent mode : bus-monitoring mode */
priv->write_reg(priv, &priv->regs->control, CONTROL_EIE |
CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
priv->write_reg(priv, &priv->regs->test, TEST_SILENT);
} else
/* normal mode*/
priv->write_reg(priv, &priv->regs->control,
CONTROL_EIE | CONTROL_SIE | CONTROL_IE);
/* configure message objects */
c_can_configure_msg_objects(dev);
/* set a `lec` value so that we can check for updates later */
priv->write_reg(priv, &priv->regs->status, LEC_UNUSED);
/* set bittiming params */
c_can_set_bittiming(dev);
}
static void c_can_start(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
/* basic c_can configuration */
c_can_chip_config(dev);
priv->can.state = CAN_STATE_ERROR_ACTIVE;
/* reset tx helper pointers */
priv->tx_next = priv->tx_echo = 0;
/* enable status change, error and module interrupts */
c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
}
static void c_can_stop(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
/* disable all interrupts */
c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
/* set the state as STOPPED */
priv->can.state = CAN_STATE_STOPPED;
}
static int c_can_set_mode(struct net_device *dev, enum can_mode mode)
{
switch (mode) {
case CAN_MODE_START:
c_can_start(dev);
netif_wake_queue(dev);
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int c_can_get_berr_counter(const struct net_device *dev,
struct can_berr_counter *bec)
{
unsigned int reg_err_counter;
struct c_can_priv *priv = netdev_priv(dev);
reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt);
bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >>
ERR_CNT_REC_SHIFT;
bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK;
return 0;
}
/*
* theory of operation:
*
* priv->tx_echo holds the number of the oldest can_frame put for
* transmission into the hardware, but not yet ACKed by the CAN tx
* complete IRQ.
*
* We iterate from priv->tx_echo to priv->tx_next and check if the
* packet has been transmitted, echo it back to the CAN framework.
* If we discover a not yet transmitted package, stop looking for more.
*/
static void c_can_do_tx(struct net_device *dev)
{
u32 val;
u32 msg_obj_no;
struct c_can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
msg_obj_no = get_tx_echo_msg_obj(priv);
val = c_can_read_reg32(priv, &priv->regs->txrqst1);
if (!(val & (1 << msg_obj_no))) {
can_get_echo_skb(dev,
msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
stats->tx_bytes += priv->read_reg(priv,
&priv->regs->ifregs[0].msg_cntrl)
& IF_MCONT_DLC_MASK;
stats->tx_packets++;
c_can_inval_msg_object(dev, 0, msg_obj_no);
}
}
/* restart queue if wrap-up or if queue stalled on last pkt */
if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0))
netif_wake_queue(dev);
}
/*
* theory of operation:
*
* c_can core saves a received CAN message into the first free message
* object it finds free (starting with the lowest). Bits NEWDAT and
* INTPND are set for this message object indicating that a new message
* has arrived. To work-around this issue, we keep two groups of message
* objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT.
*
* To ensure in-order frame reception we use the following
* approach while re-activating a message object to receive further
* frames:
* - if the current message object number is lower than
* C_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing
* the INTPND bit.
* - if the current message object number is equal to
* C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower
* receive message objects.
* - if the current message object number is greater than
* C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of
* only this message object.
*/
static int c_can_do_rx_poll(struct net_device *dev, int quota)
{
u32 num_rx_pkts = 0;
unsigned int msg_obj, msg_ctrl_save;
struct c_can_priv *priv = netdev_priv(dev);
u32 val = c_can_read_reg32(priv, &priv->regs->intpnd1);
for (msg_obj = C_CAN_MSG_OBJ_RX_FIRST;
msg_obj <= C_CAN_MSG_OBJ_RX_LAST && quota > 0;
val = c_can_read_reg32(priv, &priv->regs->intpnd1),
msg_obj++) {
/*
* as interrupt pending register's bit n-1 corresponds to
* message object n, we need to handle the same properly.
*/
if (val & (1 << (msg_obj - 1))) {
c_can_object_get(dev, 0, msg_obj, IF_COMM_ALL &
~IF_COMM_TXRQST);
msg_ctrl_save = priv->read_reg(priv,
&priv->regs->ifregs[0].msg_cntrl);
if (msg_ctrl_save & IF_MCONT_EOB)
return num_rx_pkts;
if (msg_ctrl_save & IF_MCONT_MSGLST) {
c_can_handle_lost_msg_obj(dev, 0, msg_obj);
num_rx_pkts++;
quota--;
continue;
}
if (!(msg_ctrl_save & IF_MCONT_NEWDAT))
continue;
/* read the data from the message object */
c_can_read_msg_object(dev, 0, msg_ctrl_save);
if (msg_obj < C_CAN_MSG_RX_LOW_LAST)
c_can_mark_rx_msg_obj(dev, 0,
msg_ctrl_save, msg_obj);
else if (msg_obj > C_CAN_MSG_RX_LOW_LAST)
/* activate this msg obj */
c_can_activate_rx_msg_obj(dev, 0,
msg_ctrl_save, msg_obj);
else if (msg_obj == C_CAN_MSG_RX_LOW_LAST)
/* activate all lower message objects */
c_can_activate_all_lower_rx_msg_obj(dev,
0, msg_ctrl_save);
num_rx_pkts++;
quota--;
}
}
return num_rx_pkts;
}
static inline int c_can_has_and_handle_berr(struct c_can_priv *priv)
{
return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
(priv->current_status & LEC_UNUSED);
}
static int c_can_handle_state_change(struct net_device *dev,
enum c_can_bus_error_types error_type)
{
unsigned int reg_err_counter;
unsigned int rx_err_passive;
struct c_can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct can_frame *cf;
struct sk_buff *skb;
struct can_berr_counter bec;
/* propagate the error condition to the CAN stack */
skb = alloc_can_err_skb(dev, &cf);
if (unlikely(!skb))
return 0;
c_can_get_berr_counter(dev, &bec);
reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt);
rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >>
ERR_CNT_RP_SHIFT;
switch (error_type) {
case C_CAN_ERROR_WARNING:
/* error warning state */
priv->can.can_stats.error_warning++;
priv->can.state = CAN_STATE_ERROR_WARNING;
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] = (bec.txerr > bec.rxerr) ?
CAN_ERR_CRTL_TX_WARNING :
CAN_ERR_CRTL_RX_WARNING;
cf->data[6] = bec.txerr;
cf->data[7] = bec.rxerr;
break;
case C_CAN_ERROR_PASSIVE:
/* error passive state */
priv->can.can_stats.error_passive++;
priv->can.state = CAN_STATE_ERROR_PASSIVE;
cf->can_id |= CAN_ERR_CRTL;
if (rx_err_passive)
cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
if (bec.txerr > 127)
cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
cf->data[6] = bec.txerr;
cf->data[7] = bec.rxerr;
break;
case C_CAN_BUS_OFF:
/* bus-off state */
priv->can.state = CAN_STATE_BUS_OFF;
cf->can_id |= CAN_ERR_BUSOFF;
/*
* disable all interrupts in bus-off mode to ensure that
* the CPU is not hogged down
*/
c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
can_bus_off(dev);
break;
default:
break;
}
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
return 1;
}
static int c_can_handle_bus_err(struct net_device *dev,
enum c_can_lec_type lec_type)
{
struct c_can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct can_frame *cf;
struct sk_buff *skb;
/*
* early exit if no lec update or no error.
* no lec update means that no CAN bus event has been detected
* since CPU wrote 0x7 value to status reg.
*/
if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
return 0;
/* propagate the error condition to the CAN stack */
skb = alloc_can_err_skb(dev, &cf);
if (unlikely(!skb))
return 0;
/*
* check for 'last error code' which tells us the
* type of the last error to occur on the CAN bus
*/
/* common for all type of bus errors */
priv->can.can_stats.bus_error++;
stats->rx_errors++;
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
cf->data[2] |= CAN_ERR_PROT_UNSPEC;
switch (lec_type) {
case LEC_STUFF_ERROR:
netdev_dbg(dev, "stuff error\n");
cf->data[2] |= CAN_ERR_PROT_STUFF;
break;
case LEC_FORM_ERROR:
netdev_dbg(dev, "form error\n");
cf->data[2] |= CAN_ERR_PROT_FORM;
break;
case LEC_ACK_ERROR:
netdev_dbg(dev, "ack error\n");
cf->data[2] |= (CAN_ERR_PROT_LOC_ACK |
CAN_ERR_PROT_LOC_ACK_DEL);
break;
case LEC_BIT1_ERROR:
netdev_dbg(dev, "bit1 error\n");
cf->data[2] |= CAN_ERR_PROT_BIT1;
break;
case LEC_BIT0_ERROR:
netdev_dbg(dev, "bit0 error\n");
cf->data[2] |= CAN_ERR_PROT_BIT0;
break;
case LEC_CRC_ERROR:
netdev_dbg(dev, "CRC error\n");
cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
CAN_ERR_PROT_LOC_CRC_DEL);
break;
default:
break;
}
/* set a `lec` value so that we can check for updates later */
priv->write_reg(priv, &priv->regs->status, LEC_UNUSED);
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
return 1;
}
static int c_can_poll(struct napi_struct *napi, int quota)
{
u16 irqstatus;
int lec_type = 0;
int work_done = 0;
struct net_device *dev = napi->dev;
struct c_can_priv *priv = netdev_priv(dev);
irqstatus = priv->read_reg(priv, &priv->regs->interrupt);
if (!irqstatus)
goto end;
/* status events have the highest priority */
if (irqstatus == STATUS_INTERRUPT) {
priv->current_status = priv->read_reg(priv,
&priv->regs->status);
/* handle Tx/Rx events */
if (priv->current_status & STATUS_TXOK)
priv->write_reg(priv, &priv->regs->status,
priv->current_status & ~STATUS_TXOK);
if (priv->current_status & STATUS_RXOK)
priv->write_reg(priv, &priv->regs->status,
priv->current_status & ~STATUS_RXOK);
/* handle state changes */
if ((priv->current_status & STATUS_EWARN) &&
(!(priv->last_status & STATUS_EWARN))) {
netdev_dbg(dev, "entered error warning state\n");
work_done += c_can_handle_state_change(dev,
C_CAN_ERROR_WARNING);
}
if ((priv->current_status & STATUS_EPASS) &&
(!(priv->last_status & STATUS_EPASS))) {
netdev_dbg(dev, "entered error passive state\n");
work_done += c_can_handle_state_change(dev,
C_CAN_ERROR_PASSIVE);
}
if ((priv->current_status & STATUS_BOFF) &&
(!(priv->last_status & STATUS_BOFF))) {
netdev_dbg(dev, "entered bus off state\n");
work_done += c_can_handle_state_change(dev,
C_CAN_BUS_OFF);
}
/* handle bus recovery events */
if ((!(priv->current_status & STATUS_BOFF)) &&
(priv->last_status & STATUS_BOFF)) {
netdev_dbg(dev, "left bus off state\n");
priv->can.state = CAN_STATE_ERROR_ACTIVE;
}
if ((!(priv->current_status & STATUS_EPASS)) &&
(priv->last_status & STATUS_EPASS)) {
netdev_dbg(dev, "left error passive state\n");
priv->can.state = CAN_STATE_ERROR_ACTIVE;
}
priv->last_status = priv->current_status;
/* handle lec errors on the bus */
lec_type = c_can_has_and_handle_berr(priv);
if (lec_type)
work_done += c_can_handle_bus_err(dev, lec_type);
} else if ((irqstatus >= C_CAN_MSG_OBJ_RX_FIRST) &&
(irqstatus <= C_CAN_MSG_OBJ_RX_LAST)) {
/* handle events corresponding to receive message objects */
work_done += c_can_do_rx_poll(dev, (quota - work_done));
} else if ((irqstatus >= C_CAN_MSG_OBJ_TX_FIRST) &&
(irqstatus <= C_CAN_MSG_OBJ_TX_LAST)) {
/* handle events corresponding to transmit message objects */
c_can_do_tx(dev);
}
end:
if (work_done < quota) {
napi_complete(napi);
/* enable all IRQs */
c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
}
return work_done;
}
static irqreturn_t c_can_isr(int irq, void *dev_id)
{
u16 irqstatus;
struct net_device *dev = (struct net_device *)dev_id;
struct c_can_priv *priv = netdev_priv(dev);
irqstatus = priv->read_reg(priv, &priv->regs->interrupt);
if (!irqstatus)
return IRQ_NONE;
/* disable all interrupts and schedule the NAPI */
c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
napi_schedule(&priv->napi);
return IRQ_HANDLED;
}
static int c_can_open(struct net_device *dev)
{
int err;
struct c_can_priv *priv = netdev_priv(dev);
/* open the can device */
err = open_candev(dev);
if (err) {
netdev_err(dev, "failed to open can device\n");
return err;
}
/* register interrupt handler */
err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name,
dev);
if (err < 0) {
netdev_err(dev, "failed to request interrupt\n");
goto exit_irq_fail;
}
/* start the c_can controller */
c_can_start(dev);
napi_enable(&priv->napi);
netif_start_queue(dev);
return 0;
exit_irq_fail:
close_candev(dev);
return err;
}
static int c_can_close(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
netif_stop_queue(dev);
napi_disable(&priv->napi);
c_can_stop(dev);
free_irq(dev->irq, dev);
close_candev(dev);
return 0;
}
struct net_device *alloc_c_can_dev(void)
{
struct net_device *dev;
struct c_can_priv *priv;
dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
if (!dev)
return NULL;
priv = netdev_priv(dev);
netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
priv->dev = dev;
priv->can.bittiming_const = &c_can_bittiming_const;
priv->can.do_set_mode = c_can_set_mode;
priv->can.do_get_berr_counter = c_can_get_berr_counter;
priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
CAN_CTRLMODE_LISTENONLY |
CAN_CTRLMODE_BERR_REPORTING;
return dev;
}
EXPORT_SYMBOL_GPL(alloc_c_can_dev);
void free_c_can_dev(struct net_device *dev)
{
free_candev(dev);
}
EXPORT_SYMBOL_GPL(free_c_can_dev);
static const struct net_device_ops c_can_netdev_ops = {
.ndo_open = c_can_open,
.ndo_stop = c_can_close,
.ndo_start_xmit = c_can_start_xmit,
};
int register_c_can_dev(struct net_device *dev)
{
dev->flags |= IFF_ECHO; /* we support local echo */
dev->netdev_ops = &c_can_netdev_ops;
return register_candev(dev);
}
EXPORT_SYMBOL_GPL(register_c_can_dev);
void unregister_c_can_dev(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
/* disable all interrupts */
c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
unregister_candev(dev);
}
EXPORT_SYMBOL_GPL(unregister_c_can_dev);
MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");
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