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linux-stable/drivers/net/can/at91_can.c
Marc Kleine-Budde 3a5655a5b5 can: at91_can: make can_id of mailbox 0 configurable 
Due to a chip bug (errata 50.2.6.3 & 50.3.5.3 in
"AT91SAM9263 Preliminary 6249H-ATARM-27-Jul-09") the contents of mailbox
0 may be send under certain conditions (even if disabled or in rx mode).

The workaround in the errata suggests not to use the mailbox and load it
with an unused identifier.

This patch implements the second part of the workaround. A sysfs entry
"mb0_id" is introduced. While the interface is down it can be used to
configure the can_id of mailbox 0. The default value id 0x7ff.

In order to use an extended can_id add the CAN_EFF_FLAG (0x80000000U)
to the can_id. Example:

- standard id 0x7ff:
echo 0x7ff      > /sys/class/net/can0/mb0_id

- extended id 0x1fffffff:
echo 0x9fffffff > /sys/class/net/can0/mb0_id

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
For the Documentation-part:
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-01-24 14:56:37 +01:00

1257 lines
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/*
* at91_can.c - CAN network driver for AT91 SoC CAN controller
*
* (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
* (C) 2008, 2009, 2010, 2011 by Marc Kleine-Budde <kernel@pengutronix.de>
*
* This software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2 as distributed in the 'COPYING'
* file from the main directory of the linux kernel source.
*
* Send feedback to <socketcan-users@lists.berlios.de>
*
*
* Your platform definition file should specify something like:
*
* static struct at91_can_data ek_can_data = {
* transceiver_switch = sam9263ek_transceiver_switch,
* };
*
* at91_add_device_can(&ek_can_data);
*
*/
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.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 <mach/board.h>
#define AT91_NAPI_WEIGHT 11
/*
* RX/TX Mailbox split
* don't dare to touch
*/
#define AT91_MB_RX_NUM 11
#define AT91_MB_TX_SHIFT 2
#define AT91_MB_RX_FIRST 1
#define AT91_MB_RX_LAST (AT91_MB_RX_FIRST + AT91_MB_RX_NUM - 1)
#define AT91_MB_RX_MASK(i) ((1 << (i)) - 1)
#define AT91_MB_RX_SPLIT 8
#define AT91_MB_RX_LOW_LAST (AT91_MB_RX_SPLIT - 1)
#define AT91_MB_RX_LOW_MASK (AT91_MB_RX_MASK(AT91_MB_RX_SPLIT) & \
~AT91_MB_RX_MASK(AT91_MB_RX_FIRST))
#define AT91_MB_TX_NUM (1 << AT91_MB_TX_SHIFT)
#define AT91_MB_TX_FIRST (AT91_MB_RX_LAST + 1)
#define AT91_MB_TX_LAST (AT91_MB_TX_FIRST + AT91_MB_TX_NUM - 1)
#define AT91_NEXT_PRIO_SHIFT (AT91_MB_TX_SHIFT)
#define AT91_NEXT_PRIO_MASK (0xf << AT91_MB_TX_SHIFT)
#define AT91_NEXT_MB_MASK (AT91_MB_TX_NUM - 1)
#define AT91_NEXT_MASK ((AT91_MB_TX_NUM - 1) | AT91_NEXT_PRIO_MASK)
/* 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_MB_RX ((1 << (AT91_MB_RX_LAST + 1)) \
- (1 << AT91_MB_RX_FIRST))
#define AT91_IRQ_MB_TX ((1 << (AT91_MB_TX_LAST + 1)) \
- (1 << AT91_MB_TX_FIRST))
#define AT91_IRQ_MB_ALL (AT91_IRQ_MB_RX | AT91_IRQ_MB_TX)
#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)
struct at91_priv {
struct can_priv can; /* must be the first member! */
struct net_device *dev;
struct napi_struct napi;
void __iomem *reg_base;
u32 reg_sr;
unsigned int tx_next;
unsigned int tx_echo;
unsigned int rx_next;
struct clk *clk;
struct at91_can_data *pdata;
canid_t mb0_id;
};
static 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,
};
static inline int get_tx_next_mb(const struct at91_priv *priv)
{
return (priv->tx_next & AT91_NEXT_MB_MASK) + AT91_MB_TX_FIRST;
}
static inline int get_tx_next_prio(const struct at91_priv *priv)
{
return (priv->tx_next >> AT91_NEXT_PRIO_SHIFT) & 0xf;
}
static inline int get_tx_echo_mb(const struct at91_priv *priv)
{
return (priv->tx_echo & AT91_NEXT_MB_MASK) + AT91_MB_TX_FIRST;
}
static inline u32 at91_read(const struct at91_priv *priv, enum at91_reg reg)
{
return __raw_readl(priv->reg_base + reg);
}
static inline void at91_write(const struct at91_priv *priv, enum at91_reg reg,
u32 value)
{
__raw_writel(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;
}
/*
* Swtich transceiver on or off
*/
static void at91_transceiver_switch(const struct at91_priv *priv, int on)
{
if (priv->pdata && priv->pdata->transceiver_switch)
priv->pdata->transceiver_switch(on);
}
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 < AT91_MB_RX_FIRST; 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 = AT91_MB_RX_FIRST; i < AT91_MB_RX_LAST; i++)
set_mb_mode(priv, i, AT91_MB_MODE_RX);
set_mb_mode(priv, AT91_MB_RX_LAST, AT91_MB_MODE_RX_OVRWR);
/* reset acceptance mask and id register */
for (i = AT91_MB_RX_FIRST; i <= AT91_MB_RX_LAST; 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 = AT91_MB_TX_FIRST; i <= AT91_MB_TX_LAST; 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 = AT91_MB_RX_FIRST;
}
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);
at91_transceiver_switch(priv, 1);
/* enable chip */
at91_write(priv, AT91_MR, AT91_MR_CANEN);
priv->can.state = CAN_STATE_ERROR_ACTIVE;
/* Enable interrupts */
reg_ier = AT91_IRQ_MB_RX | 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);
at91_transceiver_switch(priv, 0);
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 << AT91_NEXT_PRIO_SHIFT) ||
* (mb - AT91_MB_TX_FIRST);
*
*/
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_: substract AT91_MB_TX_FIRST offset from mb! */
can_put_echo_skb(skb, dev, mb - AT91_MB_TX_FIRST);
/*
* 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 & AT91_NEXT_MASK) == 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 = AT91_MB_RX_LOW_MASK;
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;
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
}
/**
* 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));
if (reg_msr & AT91_MSR_MRTR)
cf->can_id |= CAN_RTR_FLAG;
cf->can_dlc = get_can_dlc((reg_msr >> 16) & 0xf);
*(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 == AT91_MB_RX_LAST && 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);
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
}
/**
* 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:
*
* 11 of the 16 mailboxes on the chip are reserved for RX. we split
* them into 2 groups. The lower group holds 7 and upper 4 mailboxes.
*
* 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 *)&reg_sr;
unsigned int mb;
int received = 0;
if (priv->rx_next > AT91_MB_RX_LOW_LAST &&
reg_sr & AT91_MB_RX_LOW_MASK)
netdev_info(dev,
"order of incoming frames cannot be guaranteed\n");
again:
for (mb = find_next_bit(addr, AT91_MB_RX_LAST + 1, priv->rx_next);
mb < AT91_MB_RX_LAST + 1 && quota > 0;
reg_sr = at91_read(priv, AT91_SR),
mb = find_next_bit(addr, AT91_MB_RX_LAST + 1, ++priv->rx_next)) {
at91_read_msg(dev, mb);
/* reactivate mailboxes */
if (mb == AT91_MB_RX_LOW_LAST)
/* all lower mailboxed, if just finished it */
at91_activate_rx_low(priv);
else if (mb > AT91_MB_RX_LOW_LAST)
/* only the mailbox we read */
at91_activate_rx_mb(priv, mb);
received++;
quota--;
}
/* upper group completed, look again in lower */
if (priv->rx_next > AT91_MB_RX_LOW_LAST &&
quota > 0 && mb > AT91_MB_RX_LAST) {
priv->rx_next = AT91_MB_RX_FIRST;
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);
netif_receive_skb(skb);
dev->stats.rx_packets++;
dev->stats.rx_bytes += cf->can_dlc;
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 & AT91_IRQ_MB_RX)
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 |= AT91_IRQ_MB_RX & ~AT91_MB_RX_MASK(priv->rx_next);
napi_complete(napi);
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_: substract AT91_MB_TX_FIRST offset from mb! */
can_get_echo_skb(dev, mb - AT91_MB_TX_FIRST);
dev->stats.tx_packets++;
}
}
/*
* 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 & AT91_NEXT_MASK) != 0 ||
(priv->tx_echo & AT91_NEXT_MASK) == 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;
}
case CAN_STATE_ERROR_WARNING: /* fallthrough */
/*
* 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;
case CAN_STATE_ERROR_WARNING: /* fallthrough */
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 void at91_irq_err(struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
struct sk_buff *skb;
struct can_frame *cf;
enum can_state new_state;
u32 reg_sr;
reg_sr = at91_read(priv, AT91_SR);
/* we need to look at the unmasked reg_sr */
if (unlikely(reg_sr & AT91_IRQ_BOFF))
new_state = CAN_STATE_BUS_OFF;
else if (unlikely(reg_sr & AT91_IRQ_ERRP))
new_state = CAN_STATE_ERROR_PASSIVE;
else if (unlikely(reg_sr & AT91_IRQ_WARN))
new_state = CAN_STATE_ERROR_WARNING;
else if (likely(reg_sr & AT91_IRQ_ERRA))
new_state = CAN_STATE_ERROR_ACTIVE;
else {
netdev_err(dev, "BUG! hardware in undefined state\n");
return;
}
/* state hasn't changed */
if (likely(new_state == priv->can.state))
return;
skb = alloc_can_err_skb(dev, &cf);
if (unlikely(!skb))
return;
at91_irq_err_state(dev, cf, new_state);
netif_rx(skb);
dev->stats.rx_packets++;
dev->stats.rx_bytes += cf->can_dlc;
priv->can.state = new_state;
}
/*
* interrupt handler
*/
static irqreturn_t at91_irq(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
struct at91_priv *priv = netdev_priv(dev);
irqreturn_t handled = IRQ_NONE;
u32 reg_sr, reg_imr;
reg_sr = at91_read(priv, AT91_SR);
reg_imr = at91_read(priv, AT91_IMR);
/* Ignore masked interrupts */
reg_sr &= reg_imr;
if (!reg_sr)
goto exit;
handled = IRQ_HANDLED;
/* Receive or error interrupt? -> napi */
if (reg_sr & (AT91_IRQ_MB_RX | AT91_IRQ_ERR_FRAME)) {
/*
* The error bits are clear on read,
* save for later use.
*/
priv->reg_sr = reg_sr;
at91_write(priv, AT91_IDR,
AT91_IRQ_MB_RX | AT91_IRQ_ERR_FRAME);
napi_schedule(&priv->napi);
}
/* Transmission complete interrupt */
if (reg_sr & AT91_IRQ_MB_TX)
at91_irq_tx(dev, reg_sr);
at91_irq_err(dev);
exit:
return handled;
}
static int at91_open(struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
int err;
clk_enable(priv->clk);
/* check or determine and set bittime */
err = open_candev(dev);
if (err)
goto out;
/* register interrupt handler */
if (request_irq(dev->irq, at91_irq, IRQF_SHARED,
dev->name, dev)) {
err = -EAGAIN;
goto out_close;
}
/* start chip and queuing */
at91_chip_start(dev);
napi_enable(&priv->napi);
netif_start_queue(dev);
return 0;
out_close:
close_candev(dev);
out:
clk_disable(priv->clk);
return err;
}
/*
* stop CAN bus activity
*/
static int at91_close(struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
netif_stop_queue(dev);
napi_disable(&priv->napi);
at91_chip_stop(dev, CAN_STATE_STOPPED);
free_irq(dev->irq, dev);
clk_disable(priv->clk);
close_candev(dev);
return 0;
}
static int at91_set_mode(struct net_device *dev, enum can_mode mode)
{
switch (mode) {
case CAN_MODE_START:
at91_chip_start(dev);
netif_wake_queue(dev);
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static const struct net_device_ops at91_netdev_ops = {
.ndo_open = at91_open,
.ndo_stop = at91_close,
.ndo_start_xmit = at91_start_xmit,
};
static ssize_t at91_sysfs_show_mb0_id(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct at91_priv *priv = netdev_priv(to_net_dev(dev));
if (priv->mb0_id & CAN_EFF_FLAG)
return snprintf(buf, PAGE_SIZE, "0x%08x\n", priv->mb0_id);
else
return snprintf(buf, PAGE_SIZE, "0x%03x\n", priv->mb0_id);
}
static ssize_t at91_sysfs_set_mb0_id(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct net_device *ndev = to_net_dev(dev);
struct at91_priv *priv = netdev_priv(ndev);
unsigned long can_id;
ssize_t ret;
int err;
rtnl_lock();
if (ndev->flags & IFF_UP) {
ret = -EBUSY;
goto out;
}
err = strict_strtoul(buf, 0, &can_id);
if (err) {
ret = err;
goto out;
}
if (can_id & CAN_EFF_FLAG)
can_id &= CAN_EFF_MASK | CAN_EFF_FLAG;
else
can_id &= CAN_SFF_MASK;
priv->mb0_id = can_id;
ret = count;
out:
rtnl_unlock();
return ret;
}
static DEVICE_ATTR(mb0_id, S_IWUGO | S_IRUGO,
at91_sysfs_show_mb0_id, at91_sysfs_set_mb0_id);
static struct attribute *at91_sysfs_attrs[] = {
&dev_attr_mb0_id.attr,
NULL,
};
static struct attribute_group at91_sysfs_attr_group = {
.attrs = at91_sysfs_attrs,
};
static int __devinit at91_can_probe(struct platform_device *pdev)
{
struct net_device *dev;
struct at91_priv *priv;
struct resource *res;
struct clk *clk;
void __iomem *addr;
int err, irq;
clk = clk_get(&pdev->dev, "can_clk");
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "no clock defined\n");
err = -ENODEV;
goto exit;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq = platform_get_irq(pdev, 0);
if (!res || irq <= 0) {
err = -ENODEV;
goto exit_put;
}
if (!request_mem_region(res->start,
resource_size(res),
pdev->name)) {
err = -EBUSY;
goto exit_put;
}
addr = ioremap_nocache(res->start, resource_size(res));
if (!addr) {
err = -ENOMEM;
goto exit_release;
}
dev = alloc_candev(sizeof(struct at91_priv), AT91_MB_TX_NUM);
if (!dev) {
err = -ENOMEM;
goto exit_iounmap;
}
dev->netdev_ops = &at91_netdev_ops;
dev->irq = irq;
dev->flags |= IFF_ECHO;
dev->sysfs_groups[0] = &at91_sysfs_attr_group;
priv = netdev_priv(dev);
priv->can.clock.freq = clk_get_rate(clk);
priv->can.bittiming_const = &at91_bittiming_const;
priv->can.do_set_mode = at91_set_mode;
priv->can.do_get_berr_counter = at91_get_berr_counter;
priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
priv->reg_base = addr;
priv->dev = dev;
priv->clk = clk;
priv->pdata = pdev->dev.platform_data;
priv->mb0_id = 0x7ff;
netif_napi_add(dev, &priv->napi, at91_poll, AT91_NAPI_WEIGHT);
dev_set_drvdata(&pdev->dev, dev);
SET_NETDEV_DEV(dev, &pdev->dev);
err = register_candev(dev);
if (err) {
dev_err(&pdev->dev, "registering netdev failed\n");
goto exit_free;
}
dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
priv->reg_base, dev->irq);
return 0;
exit_free:
free_candev(dev);
exit_iounmap:
iounmap(addr);
exit_release:
release_mem_region(res->start, resource_size(res));
exit_put:
clk_put(clk);
exit:
return err;
}
static int __devexit at91_can_remove(struct platform_device *pdev)
{
struct net_device *dev = platform_get_drvdata(pdev);
struct at91_priv *priv = netdev_priv(dev);
struct resource *res;
unregister_netdev(dev);
platform_set_drvdata(pdev, NULL);
iounmap(priv->reg_base);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(res->start, resource_size(res));
clk_put(priv->clk);
free_candev(dev);
return 0;
}
static struct platform_driver at91_can_driver = {
.probe = at91_can_probe,
.remove = __devexit_p(at91_can_remove),
.driver = {
.name = KBUILD_MODNAME,
.owner = THIS_MODULE,
},
};
static int __init at91_can_module_init(void)
{
return platform_driver_register(&at91_can_driver);
}
static void __exit at91_can_module_exit(void)
{
platform_driver_unregister(&at91_can_driver);
}
module_init(at91_can_module_init);
module_exit(at91_can_module_exit);
MODULE_AUTHOR("Marc Kleine-Budde <mkl@pengutronix.de>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION(KBUILD_MODNAME " CAN netdevice driver");
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