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at91_can.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* at91_can.c - CAN network driver for AT91 SoC CAN controller
*
* (C) 2007 by Hans J. Koch <[email protected]>
* (C) 2008, 2009, 2010, 2011 by Marc Kleine-Budde <[email protected]>
*/
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/if_arp.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
#include <linux/can/led.h>
#define AT91_MB_MASK(i) ((1 << (i)) - 1)
/* Common registers */
enum at91_reg {
AT91_MR = 0x000,
AT91_IER = 0x004,
AT91_IDR = 0x008,
AT91_IMR = 0x00C,
AT91_SR = 0x010,
AT91_BR = 0x014,
AT91_TIM = 0x018,
AT91_TIMESTP = 0x01C,
AT91_ECR = 0x020,
AT91_TCR = 0x024,
AT91_ACR = 0x028,
};
/* Mailbox registers (0 <= i <= 15) */
#define AT91_MMR(i) (enum at91_reg)(0x200 + ((i) * 0x20))
#define AT91_MAM(i) (enum at91_reg)(0x204 + ((i) * 0x20))
#define AT91_MID(i) (enum at91_reg)(0x208 + ((i) * 0x20))
#define AT91_MFID(i) (enum at91_reg)(0x20C + ((i) * 0x20))
#define AT91_MSR(i) (enum at91_reg)(0x210 + ((i) * 0x20))
#define AT91_MDL(i) (enum at91_reg)(0x214 + ((i) * 0x20))
#define AT91_MDH(i) (enum at91_reg)(0x218 + ((i) * 0x20))
#define AT91_MCR(i) (enum at91_reg)(0x21C + ((i) * 0x20))
/* Register bits */
#define AT91_MR_CANEN BIT(0)
#define AT91_MR_LPM BIT(1)
#define AT91_MR_ABM BIT(2)
#define AT91_MR_OVL BIT(3)
#define AT91_MR_TEOF BIT(4)
#define AT91_MR_TTM BIT(5)
#define AT91_MR_TIMFRZ BIT(6)
#define AT91_MR_DRPT BIT(7)
#define AT91_SR_RBSY BIT(29)
#define AT91_MMR_PRIO_SHIFT (16)
#define AT91_MID_MIDE BIT(29)
#define AT91_MSR_MRTR BIT(20)
#define AT91_MSR_MABT BIT(22)
#define AT91_MSR_MRDY BIT(23)
#define AT91_MSR_MMI BIT(24)
#define AT91_MCR_MRTR BIT(20)
#define AT91_MCR_MTCR BIT(23)
/* Mailbox Modes */
enum at91_mb_mode {
AT91_MB_MODE_DISABLED = 0,
AT91_MB_MODE_RX = 1,
AT91_MB_MODE_RX_OVRWR = 2,
AT91_MB_MODE_TX = 3,
AT91_MB_MODE_CONSUMER = 4,
AT91_MB_MODE_PRODUCER = 5,
};
/* Interrupt mask bits */
#define AT91_IRQ_ERRA (1 << 16)
#define AT91_IRQ_WARN (1 << 17)
#define AT91_IRQ_ERRP (1 << 18)
#define AT91_IRQ_BOFF (1 << 19)
#define AT91_IRQ_SLEEP (1 << 20)
#define AT91_IRQ_WAKEUP (1 << 21)
#define AT91_IRQ_TOVF (1 << 22)
#define AT91_IRQ_TSTP (1 << 23)
#define AT91_IRQ_CERR (1 << 24)
#define AT91_IRQ_SERR (1 << 25)
#define AT91_IRQ_AERR (1 << 26)
#define AT91_IRQ_FERR (1 << 27)
#define AT91_IRQ_BERR (1 << 28)
#define AT91_IRQ_ERR_ALL (0x1fff0000)
#define AT91_IRQ_ERR_FRAME (AT91_IRQ_CERR | AT91_IRQ_SERR | \
AT91_IRQ_AERR | AT91_IRQ_FERR | AT91_IRQ_BERR)
#define AT91_IRQ_ERR_LINE (AT91_IRQ_ERRA | AT91_IRQ_WARN | \
AT91_IRQ_ERRP | AT91_IRQ_BOFF)
#define AT91_IRQ_ALL (0x1fffffff)
enum at91_devtype {
AT91_DEVTYPE_SAM9263,
AT91_DEVTYPE_SAM9X5,
};
struct at91_devtype_data {
unsigned int rx_first;
unsigned int rx_split;
unsigned int rx_last;
unsigned int tx_shift;
enum at91_devtype type;
};
struct at91_priv {
struct can_priv can; /* must be the first member! */
struct napi_struct napi;
void __iomem *reg_base;
u32 reg_sr;
unsigned int tx_next;
unsigned int tx_echo;
unsigned int rx_next;
struct at91_devtype_data devtype_data;
struct clk *clk;
struct at91_can_data *pdata;
canid_t mb0_id;
};
static const struct at91_devtype_data at91_at91sam9263_data = {
.rx_first = 1,
.rx_split = 8,
.rx_last = 11,
.tx_shift = 2,
.type = AT91_DEVTYPE_SAM9263,
};
static const struct at91_devtype_data at91_at91sam9x5_data = {
.rx_first = 0,
.rx_split = 4,
.rx_last = 5,
.tx_shift = 1,
.type = AT91_DEVTYPE_SAM9X5,
};
static const struct can_bittiming_const at91_bittiming_const = {
.name = KBUILD_MODNAME,
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 2,
.brp_max = 128,
.brp_inc = 1,
};
#define AT91_IS(_model) \
static inline int at91_is_sam##_model(const struct at91_priv *priv) \
{ \
return priv->devtype_data.type == AT91_DEVTYPE_SAM##_model; \
}
AT91_IS(9263);
AT91_IS(9X5);
static inline unsigned int get_mb_rx_first(const struct at91_priv *priv)
{
return priv->devtype_data.rx_first;
}
static inline unsigned int get_mb_rx_last(const struct at91_priv *priv)
{
return priv->devtype_data.rx_last;
}
static inline unsigned int get_mb_rx_split(const struct at91_priv *priv)
{
return priv->devtype_data.rx_split;
}
static inline unsigned int get_mb_rx_num(const struct at91_priv *priv)
{
return get_mb_rx_last(priv) - get_mb_rx_first(priv) + 1;
}
static inline unsigned int get_mb_rx_low_last(const struct at91_priv *priv)
{
return get_mb_rx_split(priv) - 1;
}
static inline unsigned int get_mb_rx_low_mask(const struct at91_priv *priv)
{
return AT91_MB_MASK(get_mb_rx_split(priv)) &
~AT91_MB_MASK(get_mb_rx_first(priv));
}
static inline unsigned int get_mb_tx_shift(const struct at91_priv *priv)
{
return priv->devtype_data.tx_shift;
}
static inline unsigned int get_mb_tx_num(const struct at91_priv *priv)
{
return 1 << get_mb_tx_shift(priv);
}
static inline unsigned int get_mb_tx_first(const struct at91_priv *priv)
{
return get_mb_rx_last(priv) + 1;
}
static inline unsigned int get_mb_tx_last(const struct at91_priv *priv)
{
return get_mb_tx_first(priv) + get_mb_tx_num(priv) - 1;
}
static inline unsigned int get_next_prio_shift(const struct at91_priv *priv)
{
return get_mb_tx_shift(priv);
}
static inline unsigned int get_next_prio_mask(const struct at91_priv *priv)
{
return 0xf << get_mb_tx_shift(priv);
}
static inline unsigned int get_next_mb_mask(const struct at91_priv *priv)
{
return AT91_MB_MASK(get_mb_tx_shift(priv));
}
static inline unsigned int get_next_mask(const struct at91_priv *priv)
{
return get_next_mb_mask(priv) | get_next_prio_mask(priv);
}
static inline unsigned int get_irq_mb_rx(const struct at91_priv *priv)
{
return AT91_MB_MASK(get_mb_rx_last(priv) + 1) &
~AT91_MB_MASK(get_mb_rx_first(priv));
}
static inline unsigned int get_irq_mb_tx(const struct at91_priv *priv)
{
return AT91_MB_MASK(get_mb_tx_last(priv) + 1) &
~AT91_MB_MASK(get_mb_tx_first(priv));
}
static inline unsigned int get_tx_next_mb(const struct at91_priv *priv)
{
return (priv->tx_next & get_next_mb_mask(priv)) + get_mb_tx_first(priv);
}
static inline unsigned int get_tx_next_prio(const struct at91_priv *priv)
{
return (priv->tx_next >> get_next_prio_shift(priv)) & 0xf;
}
static inline unsigned int get_tx_echo_mb(const struct at91_priv *priv)
{
return (priv->tx_echo & get_next_mb_mask(priv)) + get_mb_tx_first(priv);
}
static inline u32 at91_read(const struct at91_priv *priv, enum at91_reg reg)
{
return readl_relaxed(priv->reg_base + reg);
}
static inline void at91_write(const struct at91_priv *priv, enum at91_reg reg,
u32 value)
{
writel_relaxed(value, priv->reg_base + reg);
}
static inline void set_mb_mode_prio(const struct at91_priv *priv,
unsigned int mb, enum at91_mb_mode mode, int prio)
{
at91_write(priv, AT91_MMR(mb), (mode << 24) | (prio << 16));
}
static inline void set_mb_mode(const struct at91_priv *priv, unsigned int mb,
enum at91_mb_mode mode)
{
set_mb_mode_prio(priv, mb, mode, 0);
}
static inline u32 at91_can_id_to_reg_mid(canid_t can_id)
{
u32 reg_mid;
if (can_id & CAN_EFF_FLAG)
reg_mid = (can_id & CAN_EFF_MASK) | AT91_MID_MIDE;
else
reg_mid = (can_id & CAN_SFF_MASK) << 18;
return reg_mid;
}
static void at91_setup_mailboxes(struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
unsigned int i;
u32 reg_mid;
/*
* Due to a chip bug (errata 50.2.6.3 & 50.3.5.3) the first
* mailbox is disabled. The next 11 mailboxes are used as a
* reception FIFO. The last mailbox is configured with
* overwrite option. The overwrite flag indicates a FIFO
* overflow.
*/
reg_mid = at91_can_id_to_reg_mid(priv->mb0_id);
for (i = 0; i < get_mb_rx_first(priv); i++) {
set_mb_mode(priv, i, AT91_MB_MODE_DISABLED);
at91_write(priv, AT91_MID(i), reg_mid);
at91_write(priv, AT91_MCR(i), 0x0); /* clear dlc */
}
for (i = get_mb_rx_first(priv); i < get_mb_rx_last(priv); i++)
set_mb_mode(priv, i, AT91_MB_MODE_RX);
set_mb_mode(priv, get_mb_rx_last(priv), AT91_MB_MODE_RX_OVRWR);
/* reset acceptance mask and id register */
for (i = get_mb_rx_first(priv); i <= get_mb_rx_last(priv); i++) {
at91_write(priv, AT91_MAM(i), 0x0);
at91_write(priv, AT91_MID(i), AT91_MID_MIDE);
}
/* The last 4 mailboxes are used for transmitting. */
for (i = get_mb_tx_first(priv); i <= get_mb_tx_last(priv); i++)
set_mb_mode_prio(priv, i, AT91_MB_MODE_TX, 0);
/* Reset tx and rx helper pointers */
priv->tx_next = priv->tx_echo = 0;
priv->rx_next = get_mb_rx_first(priv);
}
static int at91_set_bittiming(struct net_device *dev)
{
const struct at91_priv *priv = netdev_priv(dev);
const struct can_bittiming *bt = &priv->can.bittiming;
u32 reg_br;
reg_br = ((priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES) ? 1 << 24 : 0) |
((bt->brp - 1) << 16) | ((bt->sjw - 1) << 12) |
((bt->prop_seg - 1) << 8) | ((bt->phase_seg1 - 1) << 4) |
((bt->phase_seg2 - 1) << 0);
netdev_info(dev, "writing AT91_BR: 0x%08x\n", reg_br);
at91_write(priv, AT91_BR, reg_br);
return 0;
}
static int at91_get_berr_counter(const struct net_device *dev,
struct can_berr_counter *bec)
{
const struct at91_priv *priv = netdev_priv(dev);
u32 reg_ecr = at91_read(priv, AT91_ECR);
bec->rxerr = reg_ecr & 0xff;
bec->txerr = reg_ecr >> 16;
return 0;
}
static void at91_chip_start(struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
u32 reg_mr, reg_ier;
/* disable interrupts */
at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
/* disable chip */
reg_mr = at91_read(priv, AT91_MR);
at91_write(priv, AT91_MR, reg_mr & ~AT91_MR_CANEN);
at91_set_bittiming(dev);
at91_setup_mailboxes(dev);
/* enable chip */
if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
reg_mr = AT91_MR_CANEN | AT91_MR_ABM;
else
reg_mr = AT91_MR_CANEN;
at91_write(priv, AT91_MR, reg_mr);
priv->can.state = CAN_STATE_ERROR_ACTIVE;
/* Enable interrupts */
reg_ier = get_irq_mb_rx(priv) | AT91_IRQ_ERRP | AT91_IRQ_ERR_FRAME;
at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
at91_write(priv, AT91_IER, reg_ier);
}
static void at91_chip_stop(struct net_device *dev, enum can_state state)
{
struct at91_priv *priv = netdev_priv(dev);
u32 reg_mr;
/* disable interrupts */
at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
reg_mr = at91_read(priv, AT91_MR);
at91_write(priv, AT91_MR, reg_mr & ~AT91_MR_CANEN);
priv->can.state = state;
}
/*
* theory of operation:
*
* According to the datasheet priority 0 is the highest priority, 15
* is the lowest. If two mailboxes have the same priority level the
* message of the mailbox with the lowest number is sent first.
*
* We use the first TX mailbox (AT91_MB_TX_FIRST) with prio 0, then
* the next mailbox with prio 0, and so on, until all mailboxes are
* used. Then we start from the beginning with mailbox
* AT91_MB_TX_FIRST, but with prio 1, mailbox AT91_MB_TX_FIRST + 1
* prio 1. When we reach the last mailbox with prio 15, we have to
* stop sending, waiting for all messages to be delivered, then start
* again with mailbox AT91_MB_TX_FIRST prio 0.
*
* We use the priv->tx_next as counter for the next transmission
* mailbox, but without the offset AT91_MB_TX_FIRST. The lower bits
* encode the mailbox number, the upper 4 bits the mailbox priority:
*
* priv->tx_next = (prio << get_next_prio_shift(priv)) |
* (mb - get_mb_tx_first(priv));
*
*/
static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct can_frame *cf = (struct can_frame *)skb->data;
unsigned int mb, prio;
u32 reg_mid, reg_mcr;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
mb = get_tx_next_mb(priv);
prio = get_tx_next_prio(priv);
if (unlikely(!(at91_read(priv, AT91_MSR(mb)) & AT91_MSR_MRDY))) {
netif_stop_queue(dev);
netdev_err(dev, "BUG! TX buffer full when queue awake!\n");
return NETDEV_TX_BUSY;
}
reg_mid = at91_can_id_to_reg_mid(cf->can_id);
reg_mcr = ((cf->can_id & CAN_RTR_FLAG) ? AT91_MCR_MRTR : 0) |
(cf->can_dlc << 16) | AT91_MCR_MTCR;
/* disable MB while writing ID (see datasheet) */
set_mb_mode(priv, mb, AT91_MB_MODE_DISABLED);
at91_write(priv, AT91_MID(mb), reg_mid);
set_mb_mode_prio(priv, mb, AT91_MB_MODE_TX, prio);
at91_write(priv, AT91_MDL(mb), *(u32 *)(cf->data + 0));
at91_write(priv, AT91_MDH(mb), *(u32 *)(cf->data + 4));
/* This triggers transmission */
at91_write(priv, AT91_MCR(mb), reg_mcr);
stats->tx_bytes += cf->can_dlc;
/* _NOTE_: subtract AT91_MB_TX_FIRST offset from mb! */
can_put_echo_skb(skb, dev, mb - get_mb_tx_first(priv));
/*
* we have to stop the queue and deliver all messages in case
* of a prio+mb counter wrap around. This is the case if
* tx_next buffer prio and mailbox equals 0.
*
* also stop the queue if next buffer is still in use
* (== not ready)
*/
priv->tx_next++;
if (!(at91_read(priv, AT91_MSR(get_tx_next_mb(priv))) &
AT91_MSR_MRDY) ||
(priv->tx_next & get_next_mask(priv)) == 0)
netif_stop_queue(dev);
/* Enable interrupt for this mailbox */
at91_write(priv, AT91_IER, 1 << mb);
return NETDEV_TX_OK;
}
/**
* at91_activate_rx_low - activate lower rx mailboxes
* @priv: a91 context
*
* Reenables the lower mailboxes for reception of new CAN messages
*/
static inline void at91_activate_rx_low(const struct at91_priv *priv)
{
u32 mask = get_mb_rx_low_mask(priv);
at91_write(priv, AT91_TCR, mask);
}
/**
* at91_activate_rx_mb - reactive single rx mailbox
* @priv: a91 context
* @mb: mailbox to reactivate
*
* Reenables given mailbox for reception of new CAN messages
*/
static inline void at91_activate_rx_mb(const struct at91_priv *priv,
unsigned int mb)
{
u32 mask = 1 << mb;
at91_write(priv, AT91_TCR, mask);
}
/**
* at91_rx_overflow_err - send error frame due to rx overflow
* @dev: net device
*/
static void at91_rx_overflow_err(struct net_device *dev)
{
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
struct can_frame *cf;
netdev_dbg(dev, "RX buffer overflow\n");
stats->rx_over_errors++;
stats->rx_errors++;
skb = alloc_can_err_skb(dev, &cf);
if (unlikely(!skb))
return;
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
netif_receive_skb(skb);
}
/**
* at91_read_mb - read CAN msg from mailbox (lowlevel impl)
* @dev: net device
* @mb: mailbox number to read from
* @cf: can frame where to store message
*
* Reads a CAN message from the given mailbox and stores data into
* given can frame. "mb" and "cf" must be valid.
*/
static void at91_read_mb(struct net_device *dev, unsigned int mb,
struct can_frame *cf)
{
const struct at91_priv *priv = netdev_priv(dev);
u32 reg_msr, reg_mid;
reg_mid = at91_read(priv, AT91_MID(mb));
if (reg_mid & AT91_MID_MIDE)
cf->can_id = ((reg_mid >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
else
cf->can_id = (reg_mid >> 18) & CAN_SFF_MASK;
reg_msr = at91_read(priv, AT91_MSR(mb));
cf->can_dlc = get_can_dlc((reg_msr >> 16) & 0xf);
if (reg_msr & AT91_MSR_MRTR)
cf->can_id |= CAN_RTR_FLAG;
else {
*(u32 *)(cf->data + 0) = at91_read(priv, AT91_MDL(mb));
*(u32 *)(cf->data + 4) = at91_read(priv, AT91_MDH(mb));
}
/* allow RX of extended frames */
at91_write(priv, AT91_MID(mb), AT91_MID_MIDE);
if (unlikely(mb == get_mb_rx_last(priv) && reg_msr & AT91_MSR_MMI))
at91_rx_overflow_err(dev);
}
/**
* at91_read_msg - read CAN message from mailbox
* @dev: net device
* @mb: mail box to read from
*
* Reads a CAN message from given mailbox, and put into linux network
* RX queue, does all housekeeping chores (stats, ...)
*/
static void at91_read_msg(struct net_device *dev, unsigned int mb)
{
struct net_device_stats *stats = &dev->stats;
struct can_frame *cf;
struct sk_buff *skb;
skb = alloc_can_skb(dev, &cf);
if (unlikely(!skb)) {
stats->rx_dropped++;
return;
}
at91_read_mb(dev, mb, cf);
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
netif_receive_skb(skb);
can_led_event(dev, CAN_LED_EVENT_RX);
}
/**
* at91_poll_rx - read multiple CAN messages from mailboxes
* @dev: net device
* @quota: max number of pkgs we're allowed to receive
*
* Theory of Operation:
*
* About 3/4 of the mailboxes (get_mb_rx_first()...get_mb_rx_last())
* on the chip are reserved for RX. We split them into 2 groups. The
* lower group ranges from get_mb_rx_first() to get_mb_rx_low_last().
*
* Like it or not, but the chip always saves a received CAN message
* into the first free mailbox it finds (starting with the
* lowest). This makes it very difficult to read the messages in the
* right order from the chip. This is how we work around that problem:
*
* The first message goes into mb nr. 1 and issues an interrupt. All
* rx ints are disabled in the interrupt handler and a napi poll is
* scheduled. We read the mailbox, but do _not_ reenable the mb (to
* receive another message).
*
* lower mbxs upper
* ____^______ __^__
* / \ / \
* +-+-+-+-+-+-+-+-++-+-+-+-+
* | |x|x|x|x|x|x|x|| | | | |
* +-+-+-+-+-+-+-+-++-+-+-+-+
* 0 0 0 0 0 0 0 0 0 0 1 1 \ mail
* 0 1 2 3 4 5 6 7 8 9 0 1 / box
* ^
* |
* \
* unused, due to chip bug
*
* The variable priv->rx_next points to the next mailbox to read a
* message from. As long we're in the lower mailboxes we just read the
* mailbox but not reenable it.
*
* With completion of the last of the lower mailboxes, we reenable the
* whole first group, but continue to look for filled mailboxes in the
* upper mailboxes. Imagine the second group like overflow mailboxes,
* which takes CAN messages if the lower goup is full. While in the
* upper group we reenable the mailbox right after reading it. Giving
* the chip more room to store messages.
*
* After finishing we look again in the lower group if we've still
* quota.
*
*/
static int at91_poll_rx(struct net_device *dev, int quota)
{
struct at91_priv *priv = netdev_priv(dev);
u32 reg_sr = at91_read(priv, AT91_SR);
const unsigned long *addr = (unsigned long *)®_sr;
unsigned int mb;
int received = 0;
if (priv->rx_next > get_mb_rx_low_last(priv) &&
reg_sr & get_mb_rx_low_mask(priv))
netdev_info(dev,
"order of incoming frames cannot be guaranteed\n");
again:
for (mb = find_next_bit(addr, get_mb_tx_first(priv), priv->rx_next);
mb < get_mb_tx_first(priv) && quota > 0;
reg_sr = at91_read(priv, AT91_SR),
mb = find_next_bit(addr, get_mb_tx_first(priv), ++priv->rx_next)) {
at91_read_msg(dev, mb);
/* reactivate mailboxes */
if (mb == get_mb_rx_low_last(priv))
/* all lower mailboxed, if just finished it */
at91_activate_rx_low(priv);
else if (mb > get_mb_rx_low_last(priv))
/* only the mailbox we read */
at91_activate_rx_mb(priv, mb);
received++;
quota--;
}
/* upper group completed, look again in lower */
if (priv->rx_next > get_mb_rx_low_last(priv) &&
mb > get_mb_rx_last(priv)) {
priv->rx_next = get_mb_rx_first(priv);
if (quota > 0)
goto again;
}
return received;
}
static void at91_poll_err_frame(struct net_device *dev,
struct can_frame *cf, u32 reg_sr)
{
struct at91_priv *priv = netdev_priv(dev);
/* CRC error */
if (reg_sr & AT91_IRQ_CERR) {
netdev_dbg(dev, "CERR irq\n");
dev->stats.rx_errors++;
priv->can.can_stats.bus_error++;
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
}
/* Stuffing Error */
if (reg_sr & AT91_IRQ_SERR) {
netdev_dbg(dev, "SERR irq\n");
dev->stats.rx_errors++;
priv->can.can_stats.bus_error++;
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
cf->data[2] |= CAN_ERR_PROT_STUFF;
}
/* Acknowledgement Error */
if (reg_sr & AT91_IRQ_AERR) {
netdev_dbg(dev, "AERR irq\n");
dev->stats.tx_errors++;
cf->can_id |= CAN_ERR_ACK;
}
/* Form error */
if (reg_sr & AT91_IRQ_FERR) {
netdev_dbg(dev, "FERR irq\n");
dev->stats.rx_errors++;
priv->can.can_stats.bus_error++;
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
cf->data[2] |= CAN_ERR_PROT_FORM;
}
/* Bit Error */
if (reg_sr & AT91_IRQ_BERR) {
netdev_dbg(dev, "BERR irq\n");
dev->stats.tx_errors++;
priv->can.can_stats.bus_error++;
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
cf->data[2] |= CAN_ERR_PROT_BIT;
}
}
static int at91_poll_err(struct net_device *dev, int quota, u32 reg_sr)
{
struct sk_buff *skb;
struct can_frame *cf;
if (quota == 0)
return 0;
skb = alloc_can_err_skb(dev, &cf);
if (unlikely(!skb))
return 0;
at91_poll_err_frame(dev, cf, reg_sr);
dev->stats.rx_packets++;
dev->stats.rx_bytes += cf->can_dlc;
netif_receive_skb(skb);
return 1;
}
static int at91_poll(struct napi_struct *napi, int quota)
{
struct net_device *dev = napi->dev;
const struct at91_priv *priv = netdev_priv(dev);
u32 reg_sr = at91_read(priv, AT91_SR);
int work_done = 0;
if (reg_sr & get_irq_mb_rx(priv))
work_done += at91_poll_rx(dev, quota - work_done);
/*
* The error bits are clear on read,
* so use saved value from irq handler.
*/
reg_sr |= priv->reg_sr;
if (reg_sr & AT91_IRQ_ERR_FRAME)
work_done += at91_poll_err(dev, quota - work_done, reg_sr);
if (work_done < quota) {
/* enable IRQs for frame errors and all mailboxes >= rx_next */
u32 reg_ier = AT91_IRQ_ERR_FRAME;
reg_ier |= get_irq_mb_rx(priv) & ~AT91_MB_MASK(priv->rx_next);
napi_complete_done(napi, work_done);
at91_write(priv, AT91_IER, reg_ier);
}
return work_done;
}
/*
* 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 at91_irq_tx(struct net_device *dev, u32 reg_sr)
{
struct at91_priv *priv = netdev_priv(dev);
u32 reg_msr;
unsigned int mb;
/* masking of reg_sr not needed, already done by at91_irq */
for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
mb = get_tx_echo_mb(priv);
/* no event in mailbox? */
if (!(reg_sr & (1 << mb)))
break;
/* Disable irq for this TX mailbox */
at91_write(priv, AT91_IDR, 1 << mb);
/*
* only echo if mailbox signals us a transfer
* complete (MSR_MRDY). Otherwise it's a tansfer
* abort. "can_bus_off()" takes care about the skbs
* parked in the echo queue.
*/
reg_msr = at91_read(priv, AT91_MSR(mb));
if (likely(reg_msr & AT91_MSR_MRDY &&
~reg_msr & AT91_MSR_MABT)) {
/* _NOTE_: subtract AT91_MB_TX_FIRST offset from mb! */
can_get_echo_skb(dev, mb - get_mb_tx_first(priv));
dev->stats.tx_packets++;
can_led_event(dev, CAN_LED_EVENT_TX);
}
}
/*
* restart queue if we don't have a wrap around but restart if
* we get a TX int for the last can frame directly before a
* wrap around.
*/
if ((priv->tx_next & get_next_mask(priv)) != 0 ||
(priv->tx_echo & get_next_mask(priv)) == 0)
netif_wake_queue(dev);
}
static void at91_irq_err_state(struct net_device *dev,
struct can_frame *cf, enum can_state new_state)
{
struct at91_priv *priv = netdev_priv(dev);
u32 reg_idr = 0, reg_ier = 0;
struct can_berr_counter bec;
at91_get_berr_counter(dev, &bec);
switch (priv->can.state) {
case CAN_STATE_ERROR_ACTIVE:
/*
* from: ERROR_ACTIVE
* to : ERROR_WARNING, ERROR_PASSIVE, BUS_OFF
* => : there was a warning int
*/
if (new_state >= CAN_STATE_ERROR_WARNING &&
new_state <= CAN_STATE_BUS_OFF) {
netdev_dbg(dev, "Error Warning IRQ\n");
priv->can.can_stats.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;
}
/* fall through */
case CAN_STATE_ERROR_WARNING:
/*
* from: ERROR_ACTIVE, ERROR_WARNING
* to : ERROR_PASSIVE, BUS_OFF
* => : error passive int
*/
if (new_state >= CAN_STATE_ERROR_PASSIVE &&
new_state <= CAN_STATE_BUS_OFF) {
netdev_dbg(dev, "Error Passive IRQ\n");
priv->can.can_stats.error_passive++;
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] = (bec.txerr > bec.rxerr) ?
CAN_ERR_CRTL_TX_PASSIVE :
CAN_ERR_CRTL_RX_PASSIVE;
}
break;
case CAN_STATE_BUS_OFF:
/*
* from: BUS_OFF
* to : ERROR_ACTIVE, ERROR_WARNING, ERROR_PASSIVE
*/
if (new_state <= CAN_STATE_ERROR_PASSIVE) {
cf->can_id |= CAN_ERR_RESTARTED;
netdev_dbg(dev, "restarted\n");
priv->can.can_stats.restarts++;
netif_carrier_on(dev);
netif_wake_queue(dev);
}
break;
default:
break;
}
/* process state changes depending on the new state */
switch (new_state) {
case CAN_STATE_ERROR_ACTIVE:
/*
* actually we want to enable AT91_IRQ_WARN here, but
* it screws up the system under certain
* circumstances. so just enable AT91_IRQ_ERRP, thus
* the "fallthrough"
*/
netdev_dbg(dev, "Error Active\n");
cf->can_id |= CAN_ERR_PROT;
cf->data[2] = CAN_ERR_PROT_ACTIVE;
/* fall through */
case CAN_STATE_ERROR_WARNING:
reg_idr = AT91_IRQ_ERRA | AT91_IRQ_WARN | AT91_IRQ_BOFF;
reg_ier = AT91_IRQ_ERRP;
break;
case CAN_STATE_ERROR_PASSIVE:
reg_idr = AT91_IRQ_ERRA | AT91_IRQ_WARN | AT91_IRQ_ERRP;
reg_ier = AT91_IRQ_BOFF;
break;
case CAN_STATE_BUS_OFF:
reg_idr = AT91_IRQ_ERRA | AT91_IRQ_ERRP |
AT91_IRQ_WARN | AT91_IRQ_BOFF;
reg_ier = 0;
cf->can_id |= CAN_ERR_BUSOFF;
netdev_dbg(dev, "bus-off\n");
netif_carrier_off(dev);
priv->can.can_stats.bus_off++;
/* turn off chip, if restart is disabled */
if (!priv->can.restart_ms) {
at91_chip_stop(dev, CAN_STATE_BUS_OFF);
return;
}
break;
default:
break;
}
at91_write(priv, AT91_IDR, reg_idr);
at91_write(priv, AT91_IER, reg_ier);
}
static int at91_get_state_by_bec(const struct net_device *dev,
enum can_state *state)
{
struct can_berr_counter bec;
int err;
err = at91_get_berr_counter(dev, &bec);
if (err)
return err;
if (bec.txerr < 96 && bec.rxerr < 96)
*state = CAN_STATE_ERROR_ACTIVE;
else if (bec.txerr < 128 && bec.rxerr < 128)
*state = CAN_STATE_ERROR_WARNING;
else if (bec.txerr < 256 && bec.rxerr < 256)
*state = CAN_STATE_ERROR_PASSIVE;