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linux/drivers/net/can/grcan.c

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/*
* Socket CAN driver for Aeroflex Gaisler GRCAN and GRHCAN.
*
* 2012 (c) Aeroflex Gaisler AB
*
* This driver supports GRCAN and GRHCAN CAN controllers available in the GRLIB
* VHDL IP core library.
*
* Full documentation of the GRCAN core can be found here:
* http://www.gaisler.com/products/grlib/grip.pdf
*
* See "Documentation/devicetree/bindings/net/can/grcan.txt" for information on
* open firmware properties.
*
* See "Documentation/ABI/testing/sysfs-class-net-grcan" for information on the
* sysfs interface.
*
* See "Documentation/admin-guide/kernel-parameters.rst" for information on the module
* parameters.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* Contributors: Andreas Larsson <andreas@gaisler.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/can/dev.h>
#include <linux/spinlock.h>
#include <linux/of_platform.h>
#include <linux/of_irq.h>
#include <linux/dma-mapping.h>
#define DRV_NAME "grcan"
#define GRCAN_NAPI_WEIGHT 32
#define GRCAN_RESERVE_SIZE(slot1, slot2) (((slot2) - (slot1)) / 4 - 1)
struct grcan_registers {
u32 conf; /* 0x00 */
u32 stat; /* 0x04 */
u32 ctrl; /* 0x08 */
u32 __reserved1[GRCAN_RESERVE_SIZE(0x08, 0x18)];
u32 smask; /* 0x18 - CanMASK */
u32 scode; /* 0x1c - CanCODE */
u32 __reserved2[GRCAN_RESERVE_SIZE(0x1c, 0x100)];
u32 pimsr; /* 0x100 */
u32 pimr; /* 0x104 */
u32 pisr; /* 0x108 */
u32 pir; /* 0x10C */
u32 imr; /* 0x110 */
u32 picr; /* 0x114 */
u32 __reserved3[GRCAN_RESERVE_SIZE(0x114, 0x200)];
u32 txctrl; /* 0x200 */
u32 txaddr; /* 0x204 */
u32 txsize; /* 0x208 */
u32 txwr; /* 0x20C */
u32 txrd; /* 0x210 */
u32 txirq; /* 0x214 */
u32 __reserved4[GRCAN_RESERVE_SIZE(0x214, 0x300)];
u32 rxctrl; /* 0x300 */
u32 rxaddr; /* 0x304 */
u32 rxsize; /* 0x308 */
u32 rxwr; /* 0x30C */
u32 rxrd; /* 0x310 */
u32 rxirq; /* 0x314 */
u32 rxmask; /* 0x318 */
u32 rxcode; /* 0x31C */
};
#define GRCAN_CONF_ABORT 0x00000001
#define GRCAN_CONF_ENABLE0 0x00000002
#define GRCAN_CONF_ENABLE1 0x00000004
#define GRCAN_CONF_SELECT 0x00000008
#define GRCAN_CONF_SILENT 0x00000010
#define GRCAN_CONF_SAM 0x00000020 /* Available in some hardware */
#define GRCAN_CONF_BPR 0x00000300 /* Note: not BRP */
#define GRCAN_CONF_RSJ 0x00007000
#define GRCAN_CONF_PS1 0x00f00000
#define GRCAN_CONF_PS2 0x000f0000
#define GRCAN_CONF_SCALER 0xff000000
#define GRCAN_CONF_OPERATION \
(GRCAN_CONF_ABORT | GRCAN_CONF_ENABLE0 | GRCAN_CONF_ENABLE1 \
| GRCAN_CONF_SELECT | GRCAN_CONF_SILENT | GRCAN_CONF_SAM)
#define GRCAN_CONF_TIMING \
(GRCAN_CONF_BPR | GRCAN_CONF_RSJ | GRCAN_CONF_PS1 \
| GRCAN_CONF_PS2 | GRCAN_CONF_SCALER)
#define GRCAN_CONF_RSJ_MIN 1
#define GRCAN_CONF_RSJ_MAX 4
#define GRCAN_CONF_PS1_MIN 1
#define GRCAN_CONF_PS1_MAX 15
#define GRCAN_CONF_PS2_MIN 2
#define GRCAN_CONF_PS2_MAX 8
#define GRCAN_CONF_SCALER_MIN 0
#define GRCAN_CONF_SCALER_MAX 255
#define GRCAN_CONF_SCALER_INC 1
#define GRCAN_CONF_BPR_BIT 8
#define GRCAN_CONF_RSJ_BIT 12
#define GRCAN_CONF_PS1_BIT 20
#define GRCAN_CONF_PS2_BIT 16
#define GRCAN_CONF_SCALER_BIT 24
#define GRCAN_STAT_PASS 0x000001
#define GRCAN_STAT_OFF 0x000002
#define GRCAN_STAT_OR 0x000004
#define GRCAN_STAT_AHBERR 0x000008
#define GRCAN_STAT_ACTIVE 0x000010
#define GRCAN_STAT_RXERRCNT 0x00ff00
#define GRCAN_STAT_TXERRCNT 0xff0000
#define GRCAN_STAT_ERRCTR_RELATED (GRCAN_STAT_PASS | GRCAN_STAT_OFF)
#define GRCAN_STAT_RXERRCNT_BIT 8
#define GRCAN_STAT_TXERRCNT_BIT 16
#define GRCAN_STAT_ERRCNT_WARNING_LIMIT 96
#define GRCAN_STAT_ERRCNT_PASSIVE_LIMIT 127
#define GRCAN_CTRL_RESET 0x2
#define GRCAN_CTRL_ENABLE 0x1
#define GRCAN_TXCTRL_ENABLE 0x1
#define GRCAN_TXCTRL_ONGOING 0x2
#define GRCAN_TXCTRL_SINGLE 0x4
#define GRCAN_RXCTRL_ENABLE 0x1
#define GRCAN_RXCTRL_ONGOING 0x2
/* Relative offset of IRQ sources to AMBA Plug&Play */
#define GRCAN_IRQIX_IRQ 0
#define GRCAN_IRQIX_TXSYNC 1
#define GRCAN_IRQIX_RXSYNC 2
#define GRCAN_IRQ_PASS 0x00001
#define GRCAN_IRQ_OFF 0x00002
#define GRCAN_IRQ_OR 0x00004
#define GRCAN_IRQ_RXAHBERR 0x00008
#define GRCAN_IRQ_TXAHBERR 0x00010
#define GRCAN_IRQ_RXIRQ 0x00020
#define GRCAN_IRQ_TXIRQ 0x00040
#define GRCAN_IRQ_RXFULL 0x00080
#define GRCAN_IRQ_TXEMPTY 0x00100
#define GRCAN_IRQ_RX 0x00200
#define GRCAN_IRQ_TX 0x00400
#define GRCAN_IRQ_RXSYNC 0x00800
#define GRCAN_IRQ_TXSYNC 0x01000
#define GRCAN_IRQ_RXERRCTR 0x02000
#define GRCAN_IRQ_TXERRCTR 0x04000
#define GRCAN_IRQ_RXMISS 0x08000
#define GRCAN_IRQ_TXLOSS 0x10000
#define GRCAN_IRQ_NONE 0
#define GRCAN_IRQ_ALL \
(GRCAN_IRQ_PASS | GRCAN_IRQ_OFF | GRCAN_IRQ_OR \
| GRCAN_IRQ_RXAHBERR | GRCAN_IRQ_TXAHBERR \
| GRCAN_IRQ_RXIRQ | GRCAN_IRQ_TXIRQ \
| GRCAN_IRQ_RXFULL | GRCAN_IRQ_TXEMPTY \
| GRCAN_IRQ_RX | GRCAN_IRQ_TX | GRCAN_IRQ_RXSYNC \
| GRCAN_IRQ_TXSYNC | GRCAN_IRQ_RXERRCTR \
| GRCAN_IRQ_TXERRCTR | GRCAN_IRQ_RXMISS \
| GRCAN_IRQ_TXLOSS)
#define GRCAN_IRQ_ERRCTR_RELATED (GRCAN_IRQ_RXERRCTR | GRCAN_IRQ_TXERRCTR \
| GRCAN_IRQ_PASS | GRCAN_IRQ_OFF)
#define GRCAN_IRQ_ERRORS (GRCAN_IRQ_ERRCTR_RELATED | GRCAN_IRQ_OR \
| GRCAN_IRQ_TXAHBERR | GRCAN_IRQ_RXAHBERR \
| GRCAN_IRQ_TXLOSS)
#define GRCAN_IRQ_DEFAULT (GRCAN_IRQ_RX | GRCAN_IRQ_TX | GRCAN_IRQ_ERRORS)
#define GRCAN_MSG_SIZE 16
#define GRCAN_MSG_IDE 0x80000000
#define GRCAN_MSG_RTR 0x40000000
#define GRCAN_MSG_BID 0x1ffc0000
#define GRCAN_MSG_EID 0x1fffffff
#define GRCAN_MSG_IDE_BIT 31
#define GRCAN_MSG_RTR_BIT 30
#define GRCAN_MSG_BID_BIT 18
#define GRCAN_MSG_EID_BIT 0
#define GRCAN_MSG_DLC 0xf0000000
#define GRCAN_MSG_TXERRC 0x00ff0000
#define GRCAN_MSG_RXERRC 0x0000ff00
#define GRCAN_MSG_DLC_BIT 28
#define GRCAN_MSG_TXERRC_BIT 16
#define GRCAN_MSG_RXERRC_BIT 8
#define GRCAN_MSG_AHBERR 0x00000008
#define GRCAN_MSG_OR 0x00000004
#define GRCAN_MSG_OFF 0x00000002
#define GRCAN_MSG_PASS 0x00000001
#define GRCAN_MSG_DATA_SLOT_INDEX(i) (2 + (i) / 4)
#define GRCAN_MSG_DATA_SHIFT(i) ((3 - (i) % 4) * 8)
#define GRCAN_BUFFER_ALIGNMENT 1024
#define GRCAN_DEFAULT_BUFFER_SIZE 1024
#define GRCAN_VALID_TR_SIZE_MASK 0x001fffc0
#define GRCAN_INVALID_BUFFER_SIZE(s) \
((s) == 0 || ((s) & ~GRCAN_VALID_TR_SIZE_MASK))
#if GRCAN_INVALID_BUFFER_SIZE(GRCAN_DEFAULT_BUFFER_SIZE)
#error "Invalid default buffer size"
#endif
struct grcan_dma_buffer {
size_t size;
void *buf;
dma_addr_t handle;
};
struct grcan_dma {
size_t base_size;
void *base_buf;
dma_addr_t base_handle;
struct grcan_dma_buffer tx;
struct grcan_dma_buffer rx;
};
/* GRCAN configuration parameters */
struct grcan_device_config {
unsigned short enable0;
unsigned short enable1;
unsigned short select;
unsigned int txsize;
unsigned int rxsize;
};
#define GRCAN_DEFAULT_DEVICE_CONFIG { \
.enable0 = 0, \
.enable1 = 0, \
.select = 0, \
.txsize = GRCAN_DEFAULT_BUFFER_SIZE, \
.rxsize = GRCAN_DEFAULT_BUFFER_SIZE, \
}
#define GRCAN_TXBUG_SAFE_GRLIB_VERSION 0x4100
#define GRLIB_VERSION_MASK 0xffff
/* GRCAN private data structure */
struct grcan_priv {
struct can_priv can; /* must be the first member */
struct net_device *dev;
struct napi_struct napi;
struct grcan_registers __iomem *regs; /* ioremap'ed registers */
struct grcan_device_config config;
struct grcan_dma dma;
struct sk_buff **echo_skb; /* We allocate this on our own */
u8 *txdlc; /* Length of queued frames */
/* The echo skb pointer, pointing into echo_skb and indicating which
* frames can be echoed back. See the "Notes on the tx cyclic buffer
* handling"-comment for grcan_start_xmit for more details.
*/
u32 eskbp;
/* Lock for controlling changes to the netif tx queue state, accesses to
* the echo_skb pointer eskbp and for making sure that a running reset
* and/or a close of the interface is done without interference from
* other parts of the code.
*
* The echo_skb pointer, eskbp, should only be accessed under this lock
* as it can be changed in several places and together with decisions on
* whether to wake up the tx queue.
*
* The tx queue must never be woken up if there is a running reset or
* close in progress.
*
* A running reset (see below on need_txbug_workaround) should never be
* done if the interface is closing down and several running resets
* should never be scheduled simultaneously.
*/
spinlock_t lock;
/* Whether a workaround is needed due to a bug in older hardware. In
* this case, the driver both tries to prevent the bug from being
* triggered and recovers, if the bug nevertheless happens, by doing a
* running reset. A running reset, resets the device and continues from
* where it were without being noticeable from outside the driver (apart
* from slight delays).
*/
bool need_txbug_workaround;
/* To trigger initization of running reset and to trigger running reset
* respectively in the case of a hanged device due to a txbug.
*/
struct timer_list hang_timer;
struct timer_list rr_timer;
/* To avoid waking up the netif queue and restarting timers
* when a reset is scheduled or when closing of the device is
* undergoing
*/
bool resetting;
bool closing;
};
/* Wait time for a short wait for ongoing to clear */
#define GRCAN_SHORTWAIT_USECS 10
/* Limit on the number of transmitted bits of an eff frame according to the CAN
* specification: 1 bit start of frame, 32 bits arbitration field, 6 bits
* control field, 8 bytes data field, 16 bits crc field, 2 bits ACK field and 7
* bits end of frame
*/
#define GRCAN_EFF_FRAME_MAX_BITS (1+32+6+8*8+16+2+7)
#if defined(__BIG_ENDIAN)
static inline u32 grcan_read_reg(u32 __iomem *reg)
{
return ioread32be(reg);
}
static inline void grcan_write_reg(u32 __iomem *reg, u32 val)
{
iowrite32be(val, reg);
}
#else
static inline u32 grcan_read_reg(u32 __iomem *reg)
{
return ioread32(reg);
}
static inline void grcan_write_reg(u32 __iomem *reg, u32 val)
{
iowrite32(val, reg);
}
#endif
static inline void grcan_clear_bits(u32 __iomem *reg, u32 mask)
{
grcan_write_reg(reg, grcan_read_reg(reg) & ~mask);
}
static inline void grcan_set_bits(u32 __iomem *reg, u32 mask)
{
grcan_write_reg(reg, grcan_read_reg(reg) | mask);
}
static inline u32 grcan_read_bits(u32 __iomem *reg, u32 mask)
{
return grcan_read_reg(reg) & mask;
}
static inline void grcan_write_bits(u32 __iomem *reg, u32 value, u32 mask)
{
u32 old = grcan_read_reg(reg);
grcan_write_reg(reg, (old & ~mask) | (value & mask));
}
/* a and b should both be in [0,size] and a == b == size should not hold */
static inline u32 grcan_ring_add(u32 a, u32 b, u32 size)
{
u32 sum = a + b;
if (sum < size)
return sum;
else
return sum - size;
}
/* a and b should both be in [0,size) */
static inline u32 grcan_ring_sub(u32 a, u32 b, u32 size)
{
return grcan_ring_add(a, size - b, size);
}
/* Available slots for new transmissions */
static inline u32 grcan_txspace(size_t txsize, u32 txwr, u32 eskbp)
{
u32 slots = txsize / GRCAN_MSG_SIZE - 1;
u32 used = grcan_ring_sub(txwr, eskbp, txsize) / GRCAN_MSG_SIZE;
return slots - used;
}
/* Configuration parameters that can be set via module parameters */
static struct grcan_device_config grcan_module_config =
GRCAN_DEFAULT_DEVICE_CONFIG;
static const struct can_bittiming_const grcan_bittiming_const = {
.name = DRV_NAME,
.tseg1_min = GRCAN_CONF_PS1_MIN + 1,
.tseg1_max = GRCAN_CONF_PS1_MAX + 1,
.tseg2_min = GRCAN_CONF_PS2_MIN,
.tseg2_max = GRCAN_CONF_PS2_MAX,
.sjw_max = GRCAN_CONF_RSJ_MAX,
.brp_min = GRCAN_CONF_SCALER_MIN + 1,
.brp_max = GRCAN_CONF_SCALER_MAX + 1,
.brp_inc = GRCAN_CONF_SCALER_INC,
};
static int grcan_set_bittiming(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct can_bittiming *bt = &priv->can.bittiming;
u32 timing = 0;
int bpr, rsj, ps1, ps2, scaler;
/* Should never happen - function will not be called when
* device is up
*/
if (grcan_read_bits(&regs->ctrl, GRCAN_CTRL_ENABLE))
return -EBUSY;
bpr = 0; /* Note bpr and brp are different concepts */
rsj = bt->sjw;
ps1 = (bt->prop_seg + bt->phase_seg1) - 1; /* tseg1 - 1 */
ps2 = bt->phase_seg2;
scaler = (bt->brp - 1);
netdev_dbg(dev, "Request for BPR=%d, RSJ=%d, PS1=%d, PS2=%d, SCALER=%d",
bpr, rsj, ps1, ps2, scaler);
if (!(ps1 > ps2)) {
netdev_err(dev, "PS1 > PS2 must hold: PS1=%d, PS2=%d\n",
ps1, ps2);
return -EINVAL;
}
if (!(ps2 >= rsj)) {
netdev_err(dev, "PS2 >= RSJ must hold: PS2=%d, RSJ=%d\n",
ps2, rsj);
return -EINVAL;
}
timing |= (bpr << GRCAN_CONF_BPR_BIT) & GRCAN_CONF_BPR;
timing |= (rsj << GRCAN_CONF_RSJ_BIT) & GRCAN_CONF_RSJ;
timing |= (ps1 << GRCAN_CONF_PS1_BIT) & GRCAN_CONF_PS1;
timing |= (ps2 << GRCAN_CONF_PS2_BIT) & GRCAN_CONF_PS2;
timing |= (scaler << GRCAN_CONF_SCALER_BIT) & GRCAN_CONF_SCALER;
netdev_info(dev, "setting timing=0x%x\n", timing);
grcan_write_bits(&regs->conf, timing, GRCAN_CONF_TIMING);
return 0;
}
static int grcan_get_berr_counter(const struct net_device *dev,
struct can_berr_counter *bec)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
u32 status = grcan_read_reg(&regs->stat);
bec->txerr = (status & GRCAN_STAT_TXERRCNT) >> GRCAN_STAT_TXERRCNT_BIT;
bec->rxerr = (status & GRCAN_STAT_RXERRCNT) >> GRCAN_STAT_RXERRCNT_BIT;
return 0;
}
static int grcan_poll(struct napi_struct *napi, int budget);
/* Reset device, but keep configuration information */
static void grcan_reset(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
u32 config = grcan_read_reg(&regs->conf);
grcan_set_bits(&regs->ctrl, GRCAN_CTRL_RESET);
grcan_write_reg(&regs->conf, config);
priv->eskbp = grcan_read_reg(&regs->txrd);
priv->can.state = CAN_STATE_STOPPED;
/* Turn off hardware filtering - regs->rxcode set to 0 by reset */
grcan_write_reg(&regs->rxmask, 0);
}
/* stop device without changing any configurations */
static void grcan_stop_hardware(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
grcan_write_reg(&regs->imr, GRCAN_IRQ_NONE);
grcan_clear_bits(&regs->txctrl, GRCAN_TXCTRL_ENABLE);
grcan_clear_bits(&regs->rxctrl, GRCAN_RXCTRL_ENABLE);
grcan_clear_bits(&regs->ctrl, GRCAN_CTRL_ENABLE);
}
/* Let priv->eskbp catch up to regs->txrd and echo back the skbs if echo
* is true and free them otherwise.
*
* If budget is >= 0, stop after handling at most budget skbs. Otherwise,
* continue until priv->eskbp catches up to regs->txrd.
*
* priv->lock *must* be held when calling this function
*/
static int catch_up_echo_skb(struct net_device *dev, int budget, bool echo)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct grcan_dma *dma = &priv->dma;
struct net_device_stats *stats = &dev->stats;
int i, work_done;
/* Updates to priv->eskbp and wake-ups of the queue needs to
* be atomic towards the reads of priv->eskbp and shut-downs
* of the queue in grcan_start_xmit.
*/
u32 txrd = grcan_read_reg(&regs->txrd);
for (work_done = 0; work_done < budget || budget < 0; work_done++) {
if (priv->eskbp == txrd)
break;
i = priv->eskbp / GRCAN_MSG_SIZE;
if (echo) {
/* Normal echo of messages */
stats->tx_packets++;
stats->tx_bytes += priv->txdlc[i];
priv->txdlc[i] = 0;
can_get_echo_skb(dev, i);
} else {
/* For cleanup of untransmitted messages */
can_free_echo_skb(dev, i);
}
priv->eskbp = grcan_ring_add(priv->eskbp, GRCAN_MSG_SIZE,
dma->tx.size);
txrd = grcan_read_reg(&regs->txrd);
}
return work_done;
}
static void grcan_lost_one_shot_frame(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct grcan_dma *dma = &priv->dma;
u32 txrd;
unsigned long flags;
spin_lock_irqsave(&priv->lock, flags);
catch_up_echo_skb(dev, -1, true);
if (unlikely(grcan_read_bits(&regs->txctrl, GRCAN_TXCTRL_ENABLE))) {
/* Should never happen */
netdev_err(dev, "TXCTRL enabled at TXLOSS in one shot mode\n");
} else {
/* By the time an GRCAN_IRQ_TXLOSS is generated in
* one-shot mode there is no problem in writing
* to TXRD even in versions of the hardware in
* which GRCAN_TXCTRL_ONGOING is not cleared properly
* in one-shot mode.
*/
/* Skip message and discard echo-skb */
txrd = grcan_read_reg(&regs->txrd);
txrd = grcan_ring_add(txrd, GRCAN_MSG_SIZE, dma->tx.size);
grcan_write_reg(&regs->txrd, txrd);
catch_up_echo_skb(dev, -1, false);
if (!priv->resetting && !priv->closing &&
!(priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)) {
netif_wake_queue(dev);
grcan_set_bits(&regs->txctrl, GRCAN_TXCTRL_ENABLE);
}
}
spin_unlock_irqrestore(&priv->lock, flags);
}
static void grcan_err(struct net_device *dev, u32 sources, u32 status)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct grcan_dma *dma = &priv->dma;
struct net_device_stats *stats = &dev->stats;
struct can_frame cf;
/* Zero potential error_frame */
memset(&cf, 0, sizeof(cf));
/* Message lost interrupt. This might be due to arbitration error, but
* is also triggered when there is no one else on the can bus or when
* there is a problem with the hardware interface or the bus itself. As
* arbitration errors can not be singled out, no error frames are
* generated reporting this event as an arbitration error.
*/
if (sources & GRCAN_IRQ_TXLOSS) {
/* Take care of failed one-shot transmit */
if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
grcan_lost_one_shot_frame(dev);
/* Stop printing as soon as error passive or bus off is in
* effect to limit the amount of txloss debug printouts.
*/
if (!(status & GRCAN_STAT_ERRCTR_RELATED)) {
netdev_dbg(dev, "tx message lost\n");
stats->tx_errors++;
}
}
/* Conditions dealing with the error counters. There is no interrupt for
* error warning, but there are interrupts for increases of the error
* counters.
*/
if ((sources & GRCAN_IRQ_ERRCTR_RELATED) ||
(status & GRCAN_STAT_ERRCTR_RELATED)) {
enum can_state state = priv->can.state;
enum can_state oldstate = state;
u32 txerr = (status & GRCAN_STAT_TXERRCNT)
>> GRCAN_STAT_TXERRCNT_BIT;
u32 rxerr = (status & GRCAN_STAT_RXERRCNT)
>> GRCAN_STAT_RXERRCNT_BIT;
/* Figure out current state */
if (status & GRCAN_STAT_OFF) {
state = CAN_STATE_BUS_OFF;
} else if (status & GRCAN_STAT_PASS) {
state = CAN_STATE_ERROR_PASSIVE;
} else if (txerr >= GRCAN_STAT_ERRCNT_WARNING_LIMIT ||
rxerr >= GRCAN_STAT_ERRCNT_WARNING_LIMIT) {
state = CAN_STATE_ERROR_WARNING;
} else {
state = CAN_STATE_ERROR_ACTIVE;
}
/* Handle and report state changes */
if (state != oldstate) {
switch (state) {
case CAN_STATE_BUS_OFF:
netdev_dbg(dev, "bus-off\n");
netif_carrier_off(dev);
priv->can.can_stats.bus_off++;
/* Prevent the hardware from recovering from bus
* off on its own if restart is disabled.
*/
if (!priv->can.restart_ms)
grcan_stop_hardware(dev);
cf.can_id |= CAN_ERR_BUSOFF;
break;
case CAN_STATE_ERROR_PASSIVE:
netdev_dbg(dev, "Error passive condition\n");
priv->can.can_stats.error_passive++;
cf.can_id |= CAN_ERR_CRTL;
if (txerr >= GRCAN_STAT_ERRCNT_PASSIVE_LIMIT)
cf.data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
if (rxerr >= GRCAN_STAT_ERRCNT_PASSIVE_LIMIT)
cf.data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
break;
case CAN_STATE_ERROR_WARNING:
netdev_dbg(dev, "Error warning condition\n");
priv->can.can_stats.error_warning++;
cf.can_id |= CAN_ERR_CRTL;
if (txerr >= GRCAN_STAT_ERRCNT_WARNING_LIMIT)
cf.data[1] |= CAN_ERR_CRTL_TX_WARNING;
if (rxerr >= GRCAN_STAT_ERRCNT_WARNING_LIMIT)
cf.data[1] |= CAN_ERR_CRTL_RX_WARNING;
break;
case CAN_STATE_ERROR_ACTIVE:
netdev_dbg(dev, "Error active condition\n");
cf.can_id |= CAN_ERR_CRTL;
break;
default:
/* There are no others at this point */
break;
}
cf.data[6] = txerr;
cf.data[7] = rxerr;
priv->can.state = state;
}
/* Report automatic restarts */
if (priv->can.restart_ms && oldstate == CAN_STATE_BUS_OFF) {
unsigned long flags;
cf.can_id |= CAN_ERR_RESTARTED;
netdev_dbg(dev, "restarted\n");
priv->can.can_stats.restarts++;
netif_carrier_on(dev);
spin_lock_irqsave(&priv->lock, flags);
if (!priv->resetting && !priv->closing) {
u32 txwr = grcan_read_reg(&regs->txwr);
if (grcan_txspace(dma->tx.size, txwr,
priv->eskbp))
netif_wake_queue(dev);
}
spin_unlock_irqrestore(&priv->lock, flags);
}
}
/* Data overrun interrupt */
if ((sources & GRCAN_IRQ_OR) || (status & GRCAN_STAT_OR)) {
netdev_dbg(dev, "got data overrun interrupt\n");
stats->rx_over_errors++;
stats->rx_errors++;
cf.can_id |= CAN_ERR_CRTL;
cf.data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
}
/* AHB bus error interrupts (not CAN bus errors) - shut down the
* device.
*/
if (sources & (GRCAN_IRQ_TXAHBERR | GRCAN_IRQ_RXAHBERR) ||
(status & GRCAN_STAT_AHBERR)) {
char *txrx = "";
unsigned long flags;
if (sources & GRCAN_IRQ_TXAHBERR) {
txrx = "on tx ";
stats->tx_errors++;
} else if (sources & GRCAN_IRQ_RXAHBERR) {
txrx = "on rx ";
stats->rx_errors++;
}
netdev_err(dev, "Fatal AHB buss error %s- halting device\n",
txrx);
spin_lock_irqsave(&priv->lock, flags);
/* Prevent anything to be enabled again and halt device */
priv->closing = true;
netif_stop_queue(dev);
grcan_stop_hardware(dev);
priv->can.state = CAN_STATE_STOPPED;
spin_unlock_irqrestore(&priv->lock, flags);
}
/* Pass on error frame if something to report,
* i.e. id contains some information
*/
if (cf.can_id) {
struct can_frame *skb_cf;
struct sk_buff *skb = alloc_can_err_skb(dev, &skb_cf);
if (skb == NULL) {
netdev_dbg(dev, "could not allocate error frame\n");
return;
}
skb_cf->can_id |= cf.can_id;
memcpy(skb_cf->data, cf.data, sizeof(cf.data));
netif_rx(skb);
}
}
static irqreturn_t grcan_interrupt(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
u32 sources, status;
/* Find out the source */
sources = grcan_read_reg(&regs->pimsr);
if (!sources)
return IRQ_NONE;
grcan_write_reg(&regs->picr, sources);
status = grcan_read_reg(&regs->stat);
/* If we got TX progress, the device has not hanged,
* so disable the hang timer
*/
if (priv->need_txbug_workaround &&
(sources & (GRCAN_IRQ_TX | GRCAN_IRQ_TXLOSS))) {
del_timer(&priv->hang_timer);
}
/* Frame(s) received or transmitted */
if (sources & (GRCAN_IRQ_TX | GRCAN_IRQ_RX)) {
/* Disable tx/rx interrupts and schedule poll(). No need for
* locking as interference from a running reset at worst leads
* to an extra interrupt.
*/
grcan_clear_bits(&regs->imr, GRCAN_IRQ_TX | GRCAN_IRQ_RX);
napi_schedule(&priv->napi);
}
/* (Potential) error conditions to take care of */
if (sources & GRCAN_IRQ_ERRORS)
grcan_err(dev, sources, status);
return IRQ_HANDLED;
}
/* Reset device and restart operations from where they were.
*
* This assumes that RXCTRL & RXCTRL is properly disabled and that RX
* is not ONGOING (TX might be stuck in ONGOING due to a harwrware bug
* for single shot)
*/
static void grcan_running_reset(struct timer_list *t)
{
struct grcan_priv *priv = from_timer(priv, t, rr_timer);
struct net_device *dev = priv->dev;
struct grcan_registers __iomem *regs = priv->regs;
unsigned long flags;
/* This temporarily messes with eskbp, so we need to lock
* priv->lock
*/
spin_lock_irqsave(&priv->lock, flags);
priv->resetting = false;
del_timer(&priv->hang_timer);
del_timer(&priv->rr_timer);
if (!priv->closing) {
/* Save and reset - config register preserved by grcan_reset */
u32 imr = grcan_read_reg(&regs->imr);
u32 txaddr = grcan_read_reg(&regs->txaddr);
u32 txsize = grcan_read_reg(&regs->txsize);
u32 txwr = grcan_read_reg(&regs->txwr);
u32 txrd = grcan_read_reg(&regs->txrd);
u32 eskbp = priv->eskbp;
u32 rxaddr = grcan_read_reg(&regs->rxaddr);
u32 rxsize = grcan_read_reg(&regs->rxsize);
u32 rxwr = grcan_read_reg(&regs->rxwr);
u32 rxrd = grcan_read_reg(&regs->rxrd);
grcan_reset(dev);
/* Restore */
grcan_write_reg(&regs->txaddr, txaddr);
grcan_write_reg(&regs->txsize, txsize);
grcan_write_reg(&regs->txwr, txwr);
grcan_write_reg(&regs->txrd, txrd);
priv->eskbp = eskbp;
grcan_write_reg(&regs->rxaddr, rxaddr);
grcan_write_reg(&regs->rxsize, rxsize);
grcan_write_reg(&regs->rxwr, rxwr);
grcan_write_reg(&regs->rxrd, rxrd);
/* Turn on device again */
grcan_write_reg(&regs->imr, imr);
priv->can.state = CAN_STATE_ERROR_ACTIVE;
grcan_write_reg(&regs->txctrl, GRCAN_TXCTRL_ENABLE
| (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT
? GRCAN_TXCTRL_SINGLE : 0));
grcan_write_reg(&regs->rxctrl, GRCAN_RXCTRL_ENABLE);
grcan_write_reg(&regs->ctrl, GRCAN_CTRL_ENABLE);
/* Start queue if there is size and listen-onle mode is not
* enabled
*/
if (grcan_txspace(priv->dma.tx.size, txwr, priv->eskbp) &&
!(priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
netif_wake_queue(dev);
}
spin_unlock_irqrestore(&priv->lock, flags);
netdev_err(dev, "Device reset and restored\n");
}
/* Waiting time in usecs corresponding to the transmission of three maximum
* sized can frames in the given bitrate (in bits/sec). Waiting for this amount
* of time makes sure that the can controller have time to finish sending or
* receiving a frame with a good margin.
*
* usecs/sec * number of frames * bits/frame / bits/sec
*/
static inline u32 grcan_ongoing_wait_usecs(__u32 bitrate)
{
return 1000000 * 3 * GRCAN_EFF_FRAME_MAX_BITS / bitrate;
}
/* Set timer so that it will not fire until after a period in which the can
* controller have a good margin to finish transmitting a frame unless it has
* hanged
*/
static inline void grcan_reset_timer(struct timer_list *timer, __u32 bitrate)
{
u32 wait_jiffies = usecs_to_jiffies(grcan_ongoing_wait_usecs(bitrate));
mod_timer(timer, jiffies + wait_jiffies);
}
/* Disable channels and schedule a running reset */
static void grcan_initiate_running_reset(struct timer_list *t)
{
struct grcan_priv *priv = from_timer(priv, t, hang_timer);
struct net_device *dev = priv->dev;
struct grcan_registers __iomem *regs = priv->regs;
unsigned long flags;
netdev_err(dev, "Device seems hanged - reset scheduled\n");
spin_lock_irqsave(&priv->lock, flags);
/* The main body of this function must never be executed again
* until after an execution of grcan_running_reset
*/
if (!priv->resetting && !priv->closing) {
priv->resetting = true;
netif_stop_queue(dev);
grcan_clear_bits(&regs->txctrl, GRCAN_TXCTRL_ENABLE);
grcan_clear_bits(&regs->rxctrl, GRCAN_RXCTRL_ENABLE);
grcan_reset_timer(&priv->rr_timer, priv->can.bittiming.bitrate);
}
spin_unlock_irqrestore(&priv->lock, flags);
}
static void grcan_free_dma_buffers(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_dma *dma = &priv->dma;
dma_free_coherent(&dev->dev, dma->base_size, dma->base_buf,
dma->base_handle);
memset(dma, 0, sizeof(*dma));
}
static int grcan_allocate_dma_buffers(struct net_device *dev,
size_t tsize, size_t rsize)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_dma *dma = &priv->dma;
struct grcan_dma_buffer *large = rsize > tsize ? &dma->rx : &dma->tx;
struct grcan_dma_buffer *small = rsize > tsize ? &dma->tx : &dma->rx;
size_t shift;
/* Need a whole number of GRCAN_BUFFER_ALIGNMENT for the large,
* i.e. first buffer
*/
size_t maxs = max(tsize, rsize);
size_t lsize = ALIGN(maxs, GRCAN_BUFFER_ALIGNMENT);
/* Put the small buffer after that */
size_t ssize = min(tsize, rsize);
/* Extra GRCAN_BUFFER_ALIGNMENT to allow for alignment */
dma->base_size = lsize + ssize + GRCAN_BUFFER_ALIGNMENT;
dma->base_buf = dma_alloc_coherent(&dev->dev,
dma->base_size,
&dma->base_handle,
GFP_KERNEL);
if (!dma->base_buf)
return -ENOMEM;
dma->tx.size = tsize;
dma->rx.size = rsize;
large->handle = ALIGN(dma->base_handle, GRCAN_BUFFER_ALIGNMENT);
small->handle = large->handle + lsize;
shift = large->handle - dma->base_handle;
large->buf = dma->base_buf + shift;
small->buf = large->buf + lsize;
return 0;
}
/* priv->lock *must* be held when calling this function */
static int grcan_start(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
u32 confop, txctrl;
grcan_reset(dev);
grcan_write_reg(&regs->txaddr, priv->dma.tx.handle);
grcan_write_reg(&regs->txsize, priv->dma.tx.size);
/* regs->txwr, regs->txrd and priv->eskbp already set to 0 by reset */
grcan_write_reg(&regs->rxaddr, priv->dma.rx.handle);
grcan_write_reg(&regs->rxsize, priv->dma.rx.size);
/* regs->rxwr and regs->rxrd already set to 0 by reset */
/* Enable interrupts */
grcan_read_reg(&regs->pir);
grcan_write_reg(&regs->imr, GRCAN_IRQ_DEFAULT);
/* Enable interfaces, channels and device */
confop = GRCAN_CONF_ABORT
| (priv->config.enable0 ? GRCAN_CONF_ENABLE0 : 0)
| (priv->config.enable1 ? GRCAN_CONF_ENABLE1 : 0)
| (priv->config.select ? GRCAN_CONF_SELECT : 0)
| (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY ?
GRCAN_CONF_SILENT : 0)
| (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES ?
GRCAN_CONF_SAM : 0);
grcan_write_bits(&regs->conf, confop, GRCAN_CONF_OPERATION);
txctrl = GRCAN_TXCTRL_ENABLE
| (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT
? GRCAN_TXCTRL_SINGLE : 0);
grcan_write_reg(&regs->txctrl, txctrl);
grcan_write_reg(&regs->rxctrl, GRCAN_RXCTRL_ENABLE);
grcan_write_reg(&regs->ctrl, GRCAN_CTRL_ENABLE);
priv->can.state = CAN_STATE_ERROR_ACTIVE;
return 0;
}
static int grcan_set_mode(struct net_device *dev, enum can_mode mode)
{
struct grcan_priv *priv = netdev_priv(dev);
unsigned long flags;
int err = 0;
if (mode == CAN_MODE_START) {
/* This might be called to restart the device to recover from
* bus off errors
*/
spin_lock_irqsave(&priv->lock, flags);
if (priv->closing || priv->resetting) {
err = -EBUSY;
} else {
netdev_info(dev, "Restarting device\n");
grcan_start(dev);
if (!(priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
netif_wake_queue(dev);
}
spin_unlock_irqrestore(&priv->lock, flags);
return err;
}
return -EOPNOTSUPP;
}
static int grcan_open(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_dma *dma = &priv->dma;
unsigned long flags;
int err;
/* Allocate memory */
err = grcan_allocate_dma_buffers(dev, priv->config.txsize,
priv->config.rxsize);
if (err) {
netdev_err(dev, "could not allocate DMA buffers\n");
return err;
}
priv->echo_skb = kcalloc(dma->tx.size, sizeof(*priv->echo_skb),
GFP_KERNEL);
if (!priv->echo_skb) {
err = -ENOMEM;
goto exit_free_dma_buffers;
}
priv->can.echo_skb_max = dma->tx.size;
priv->can.echo_skb = priv->echo_skb;
priv->txdlc = kcalloc(dma->tx.size, sizeof(*priv->txdlc), GFP_KERNEL);
if (!priv->txdlc) {
err = -ENOMEM;
goto exit_free_echo_skb;
}
/* Get can device up */
err = open_candev(dev);
if (err)
goto exit_free_txdlc;
err = request_irq(dev->irq, grcan_interrupt, IRQF_SHARED,
dev->name, dev);
if (err)
goto exit_close_candev;
spin_lock_irqsave(&priv->lock, flags);
napi_enable(&priv->napi);
grcan_start(dev);
if (!(priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
netif_start_queue(dev);
priv->resetting = false;
priv->closing = false;
spin_unlock_irqrestore(&priv->lock, flags);
return 0;
exit_close_candev:
close_candev(dev);
exit_free_txdlc:
kfree(priv->txdlc);
exit_free_echo_skb:
kfree(priv->echo_skb);
exit_free_dma_buffers:
grcan_free_dma_buffers(dev);
return err;
}
static int grcan_close(struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
unsigned long flags;
napi_disable(&priv->napi);
spin_lock_irqsave(&priv->lock, flags);
priv->closing = true;
if (priv->need_txbug_workaround) {
del_timer_sync(&priv->hang_timer);
del_timer_sync(&priv->rr_timer);
}
netif_stop_queue(dev);
grcan_stop_hardware(dev);
priv->can.state = CAN_STATE_STOPPED;
spin_unlock_irqrestore(&priv->lock, flags);
free_irq(dev->irq, dev);
close_candev(dev);
grcan_free_dma_buffers(dev);
priv->can.echo_skb_max = 0;
priv->can.echo_skb = NULL;
kfree(priv->echo_skb);
kfree(priv->txdlc);
return 0;
}
static int grcan_transmit_catch_up(struct net_device *dev, int budget)
{
struct grcan_priv *priv = netdev_priv(dev);
unsigned long flags;
int work_done;
spin_lock_irqsave(&priv->lock, flags);
work_done = catch_up_echo_skb(dev, budget, true);
if (work_done) {
if (!priv->resetting && !priv->closing &&
!(priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
netif_wake_queue(dev);
/* With napi we don't get TX interrupts for a while,
* so prevent a running reset while catching up
*/
if (priv->need_txbug_workaround)
del_timer(&priv->hang_timer);
}
spin_unlock_irqrestore(&priv->lock, flags);
return work_done;
}
static int grcan_receive(struct net_device *dev, int budget)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct grcan_dma *dma = &priv->dma;
struct net_device_stats *stats = &dev->stats;
struct can_frame *cf;
struct sk_buff *skb;
u32 wr, rd, startrd;
u32 *slot;
u32 i, rtr, eff, j, shift;
int work_done = 0;
rd = grcan_read_reg(&regs->rxrd);
startrd = rd;
for (work_done = 0; work_done < budget; work_done++) {
/* Check for packet to receive */
wr = grcan_read_reg(&regs->rxwr);
if (rd == wr)
break;
/* Take care of packet */
skb = alloc_can_skb(dev, &cf);
if (skb == NULL) {
netdev_err(dev,
"dropping frame: skb allocation failed\n");
stats->rx_dropped++;
continue;
}
slot = dma->rx.buf + rd;
eff = slot[0] & GRCAN_MSG_IDE;
rtr = slot[0] & GRCAN_MSG_RTR;
if (eff) {
cf->can_id = ((slot[0] & GRCAN_MSG_EID)
>> GRCAN_MSG_EID_BIT);
cf->can_id |= CAN_EFF_FLAG;
} else {
cf->can_id = ((slot[0] & GRCAN_MSG_BID)
>> GRCAN_MSG_BID_BIT);
}
cf->can_dlc = get_can_dlc((slot[1] & GRCAN_MSG_DLC)
>> GRCAN_MSG_DLC_BIT);
if (rtr) {
cf->can_id |= CAN_RTR_FLAG;
} else {
for (i = 0; i < cf->can_dlc; i++) {
j = GRCAN_MSG_DATA_SLOT_INDEX(i);
shift = GRCAN_MSG_DATA_SHIFT(i);
cf->data[i] = (u8)(slot[j] >> shift);
}
}
/* Update statistics and read pointer */
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
netif_receive_skb(skb);
rd = grcan_ring_add(rd, GRCAN_MSG_SIZE, dma->rx.size);
}
/* Make sure everything is read before allowing hardware to
* use the memory
*/
mb();
/* Update read pointer - no need to check for ongoing */
if (likely(rd != startrd))
grcan_write_reg(&regs->rxrd, rd);
return work_done;
}
static int grcan_poll(struct napi_struct *napi, int budget)
{
struct grcan_priv *priv = container_of(napi, struct grcan_priv, napi);
struct net_device *dev = priv->dev;
struct grcan_registers __iomem *regs = priv->regs;
unsigned long flags;
int tx_work_done, rx_work_done;
int rx_budget = budget / 2;
int tx_budget = budget - rx_budget;
/* Half of the budget for receiveing messages */
rx_work_done = grcan_receive(dev, rx_budget);
/* Half of the budget for transmitting messages as that can trigger echo
* frames being received
*/
tx_work_done = grcan_transmit_catch_up(dev, tx_budget);
if (rx_work_done < rx_budget && tx_work_done < tx_budget) {
napi_complete(napi);
/* Guarantee no interference with a running reset that otherwise
* could turn off interrupts.
*/
spin_lock_irqsave(&priv->lock, flags);
/* Enable tx and rx interrupts again. No need to check
* priv->closing as napi_disable in grcan_close is waiting for
* scheduled napi calls to finish.
*/
grcan_set_bits(&regs->imr, GRCAN_IRQ_TX | GRCAN_IRQ_RX);
spin_unlock_irqrestore(&priv->lock, flags);
}
return rx_work_done + tx_work_done;
}
/* Work tx bug by waiting while for the risky situation to clear. If that fails,
* drop a frame in one-shot mode or indicate a busy device otherwise.
*
* Returns 0 on successful wait. Otherwise it sets *netdev_tx_status to the
* value that should be returned by grcan_start_xmit when aborting the xmit.
*/
static int grcan_txbug_workaround(struct net_device *dev, struct sk_buff *skb,
u32 txwr, u32 oneshotmode,
netdev_tx_t *netdev_tx_status)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct grcan_dma *dma = &priv->dma;
int i;
unsigned long flags;
/* Wait a while for ongoing to be cleared or read pointer to catch up to
* write pointer. The latter is needed due to a bug in older versions of
* GRCAN in which ONGOING is not cleared properly one-shot mode when a
* transmission fails.
*/
for (i = 0; i < GRCAN_SHORTWAIT_USECS; i++) {
udelay(1);
if (!grcan_read_bits(&regs->txctrl, GRCAN_TXCTRL_ONGOING) ||
grcan_read_reg(&regs->txrd) == txwr) {
return 0;
}
}
/* Clean up, in case the situation was not resolved */
spin_lock_irqsave(&priv->lock, flags);
if (!priv->resetting && !priv->closing) {
/* Queue might have been stopped earlier in grcan_start_xmit */
if (grcan_txspace(dma->tx.size, txwr, priv->eskbp))
netif_wake_queue(dev);
/* Set a timer to resolve a hanged tx controller */
if (!timer_pending(&priv->hang_timer))
grcan_reset_timer(&priv->hang_timer,
priv->can.bittiming.bitrate);
}
spin_unlock_irqrestore(&priv->lock, flags);
if (oneshotmode) {
/* In one-shot mode we should never end up here because
* then the interrupt handler increases txrd on TXLOSS,
* but it is consistent with one-shot mode to drop the
* frame in this case.
*/
kfree_skb(skb);
*netdev_tx_status = NETDEV_TX_OK;
} else {
/* In normal mode the socket-can transmission queue get
* to keep the frame so that it can be retransmitted
* later
*/
*netdev_tx_status = NETDEV_TX_BUSY;
}
return -EBUSY;
}
/* Notes on the tx cyclic buffer handling:
*
* regs->txwr - the next slot for the driver to put data to be sent
* regs->txrd - the next slot for the device to read data
* priv->eskbp - the next slot for the driver to call can_put_echo_skb for
*
* grcan_start_xmit can enter more messages as long as regs->txwr does
* not reach priv->eskbp (within 1 message gap)
*
* The device sends messages until regs->txrd reaches regs->txwr
*
* The interrupt calls handler calls can_put_echo_skb until
* priv->eskbp reaches regs->txrd
*/
static netdev_tx_t grcan_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct grcan_priv *priv = netdev_priv(dev);
struct grcan_registers __iomem *regs = priv->regs;
struct grcan_dma *dma = &priv->dma;
struct can_frame *cf = (struct can_frame *)skb->data;
u32 id, txwr, txrd, space, txctrl;
int slotindex;
u32 *slot;
u32 i, rtr, eff, dlc, tmp, err;
int j, shift;
unsigned long flags;
u32 oneshotmode = priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
/* Trying to transmit in silent mode will generate error interrupts, but
* this should never happen - the queue should not have been started.
*/
if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
return NETDEV_TX_BUSY;
/* Reads of priv->eskbp and shut-downs of the queue needs to
* be atomic towards the updates to priv->eskbp and wake-ups
* of the queue in the interrupt handler.
*/
spin_lock_irqsave(&priv->lock, flags);
txwr = grcan_read_reg(&regs->txwr);
space = grcan_txspace(dma->tx.size, txwr, priv->eskbp);
slotindex = txwr / GRCAN_MSG_SIZE;
slot = dma->tx.buf + txwr;
if (unlikely(space == 1))
netif_stop_queue(dev);
spin_unlock_irqrestore(&priv->lock, flags);
/* End of critical section*/
/* This should never happen. If circular buffer is full, the
* netif_stop_queue should have been stopped already.
*/
if (unlikely(!space)) {
netdev_err(dev, "No buffer space, but queue is non-stopped.\n");
return NETDEV_TX_BUSY;
}
/* Convert and write CAN message to DMA buffer */
eff = cf->can_id & CAN_EFF_FLAG;
rtr = cf->can_id & CAN_RTR_FLAG;
id = cf->can_id & (eff ? CAN_EFF_MASK : CAN_SFF_MASK);
dlc = cf->can_dlc;
if (eff)
tmp = (id << GRCAN_MSG_EID_BIT) & GRCAN_MSG_EID;
else
tmp = (id << GRCAN_MSG_BID_BIT) & GRCAN_MSG_BID;
slot[0] = (eff ? GRCAN_MSG_IDE : 0) | (rtr ? GRCAN_MSG_RTR : 0) | tmp;
slot[1] = ((dlc << GRCAN_MSG_DLC_BIT) & GRCAN_MSG_DLC);
slot[2] = 0;
slot[3] = 0;
for (i = 0; i < dlc; i++) {
j = GRCAN_MSG_DATA_SLOT_INDEX(i);
shift = GRCAN_MSG_DATA_SHIFT(i);
slot[j] |= cf->data[i] << shift;
}
/* Checking that channel has not been disabled. These cases
* should never happen
*/
txctrl = grcan_read_reg(&regs->txctrl);
if (!(txctrl & GRCAN_TXCTRL_ENABLE))
netdev_err(dev, "tx channel spuriously disabled\n");
if (oneshotmode && !(txctrl & GRCAN_TXCTRL_SINGLE))
netdev_err(dev, "one-shot mode spuriously disabled\n");
/* Bug workaround for old version of grcan where updating txwr
* in the same clock cycle as the controller updates txrd to
* the current txwr could hang the can controller
*/
if (priv->need_txbug_workaround) {
txrd = grcan_read_reg(&regs->txrd);
if (unlikely(grcan_ring_sub(txwr, txrd, dma->tx.size) == 1)) {
netdev_tx_t txstatus;
err = grcan_txbug_workaround(dev, skb, txwr,
oneshotmode, &txstatus);
if (err)
return txstatus;
}
}
/* Prepare skb for echoing. This must be after the bug workaround above
* as ownership of the skb is passed on by calling can_put_echo_skb.
* Returning NETDEV_TX_BUSY or accessing skb or cf after a call to
* can_put_echo_skb would be an error unless other measures are
* taken.
*/
priv->txdlc[slotindex] = cf->can_dlc; /* Store dlc for statistics */
can_put_echo_skb(skb, dev, slotindex);
/* Make sure everything is written before allowing hardware to
* read from the memory
*/
wmb();
/* Update write pointer to start transmission */
grcan_write_reg(&regs->txwr,
grcan_ring_add(txwr, GRCAN_MSG_SIZE, dma->tx.size));
return NETDEV_TX_OK;
}
/* ========== Setting up sysfs interface and module parameters ========== */
#define GRCAN_NOT_BOOL(unsigned_val) ((unsigned_val) > 1)
#define GRCAN_MODULE_PARAM(name, mtype, valcheckf, desc) \
static void grcan_sanitize_##name(struct platform_device *pd) \
{ \
struct grcan_device_config grcan_default_config \
= GRCAN_DEFAULT_DEVICE_CONFIG; \
if (valcheckf(grcan_module_config.name)) { \
dev_err(&pd->dev, \
"Invalid module parameter value for " \
#name " - setting default\n"); \
grcan_module_config.name = \
grcan_default_config.name; \
} \
} \
module_param_named(name, grcan_module_config.name, \
mtype, 0444); \
MODULE_PARM_DESC(name, desc)
#define GRCAN_CONFIG_ATTR(name, desc) \
static ssize_t grcan_store_##name(struct device *sdev, \
struct device_attribute *att, \
const char *buf, \
size_t count) \
{ \
struct net_device *dev = to_net_dev(sdev); \
struct grcan_priv *priv = netdev_priv(dev); \
u8 val; \
int ret; \
if (dev->flags & IFF_UP) \
return -EBUSY; \
ret = kstrtou8(buf, 0, &val); \
if (ret < 0 || val > 1) \
return -EINVAL; \
priv->config.name = val; \
return count; \
} \
static ssize_t grcan_show_##name(struct device *sdev, \
struct device_attribute *att, \
char *buf) \
{ \
struct net_device *dev = to_net_dev(sdev); \
struct grcan_priv *priv = netdev_priv(dev); \
return sprintf(buf, "%d\n", priv->config.name); \
} \
static DEVICE_ATTR(name, 0644, \
grcan_show_##name, \
grcan_store_##name); \
GRCAN_MODULE_PARAM(name, ushort, GRCAN_NOT_BOOL, desc)
/* The following configuration options are made available both via module
* parameters and writable sysfs files. See the chapter about GRCAN in the
* documentation for the GRLIB VHDL library for further details.
*/
GRCAN_CONFIG_ATTR(enable0,
"Configuration of physical interface 0. Determines\n" \
"the \"Enable 0\" bit of the configuration register.\n" \
"Format: 0 | 1\nDefault: 0\n");
GRCAN_CONFIG_ATTR(enable1,
"Configuration of physical interface 1. Determines\n" \
"the \"Enable 1\" bit of the configuration register.\n" \
"Format: 0 | 1\nDefault: 0\n");
GRCAN_CONFIG_ATTR(select,
"Select which physical interface to use.\n" \
"Format: 0 | 1\nDefault: 0\n");
/* The tx and rx buffer size configuration options are only available via module
* parameters.
*/
GRCAN_MODULE_PARAM(txsize, uint, GRCAN_INVALID_BUFFER_SIZE,
"Sets the size of the tx buffer.\n" \
"Format: <unsigned int> where (txsize & ~0x1fffc0) == 0\n" \
"Default: 1024\n");
GRCAN_MODULE_PARAM(rxsize, uint, GRCAN_INVALID_BUFFER_SIZE,
"Sets the size of the rx buffer.\n" \
"Format: <unsigned int> where (size & ~0x1fffc0) == 0\n" \
"Default: 1024\n");
/* Function that makes sure that configuration done using
* module parameters are set to valid values
*/
static void grcan_sanitize_module_config(struct platform_device *ofdev)
{
grcan_sanitize_enable0(ofdev);
grcan_sanitize_enable1(ofdev);
grcan_sanitize_select(ofdev);
grcan_sanitize_txsize(ofdev);
grcan_sanitize_rxsize(ofdev);
}
static const struct attribute *const sysfs_grcan_attrs[] = {
/* Config attrs */
&dev_attr_enable0.attr,
&dev_attr_enable1.attr,
&dev_attr_select.attr,
NULL,
};
static const struct attribute_group sysfs_grcan_group = {
.name = "grcan",
.attrs = (struct attribute **)sysfs_grcan_attrs,
};
/* ========== Setting up the driver ========== */
static const struct net_device_ops grcan_netdev_ops = {
.ndo_open = grcan_open,
.ndo_stop = grcan_close,
.ndo_start_xmit = grcan_start_xmit,
.ndo_change_mtu = can_change_mtu,
};
static int grcan_setup_netdev(struct platform_device *ofdev,
void __iomem *base,
int irq, u32 ambafreq, bool txbug)
{
struct net_device *dev;
struct grcan_priv *priv;
struct grcan_registers __iomem *regs;
int err;
dev = alloc_candev(sizeof(struct grcan_priv), 0);
if (!dev)
return -ENOMEM;
dev->irq = irq;
dev->flags |= IFF_ECHO;
dev->netdev_ops = &grcan_netdev_ops;
dev->sysfs_groups[0] = &sysfs_grcan_group;
priv = netdev_priv(dev);
memcpy(&priv->config, &grcan_module_config,
sizeof(struct grcan_device_config));
priv->dev = dev;
priv->regs = base;
priv->can.bittiming_const = &grcan_bittiming_const;
priv->can.do_set_bittiming = grcan_set_bittiming;
priv->can.do_set_mode = grcan_set_mode;
priv->can.do_get_berr_counter = grcan_get_berr_counter;
priv->can.clock.freq = ambafreq;
priv->can.ctrlmode_supported =
CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_ONE_SHOT;
priv->need_txbug_workaround = txbug;
/* Discover if triple sampling is supported by hardware */
regs = priv->regs;
grcan_set_bits(&regs->ctrl, GRCAN_CTRL_RESET);
grcan_set_bits(&regs->conf, GRCAN_CONF_SAM);
if (grcan_read_bits(&regs->conf, GRCAN_CONF_SAM)) {
priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
dev_dbg(&ofdev->dev, "Hardware supports triple-sampling\n");
}
spin_lock_init(&priv->lock);
if (priv->need_txbug_workaround) {
timer_setup(&priv->rr_timer, grcan_running_reset, 0);
timer_setup(&priv->hang_timer, grcan_initiate_running_reset, 0);
}
netif_napi_add(dev, &priv->napi, grcan_poll, GRCAN_NAPI_WEIGHT);
SET_NETDEV_DEV(dev, &ofdev->dev);
dev_info(&ofdev->dev, "regs=0x%p, irq=%d, clock=%d\n",
priv->regs, dev->irq, priv->can.clock.freq);
err = register_candev(dev);
if (err)
goto exit_free_candev;
platform_set_drvdata(ofdev, dev);
/* Reset device to allow bit-timing to be set. No need to call
* grcan_reset at this stage. That is done in grcan_open.
*/
grcan_write_reg(&regs->ctrl, GRCAN_CTRL_RESET);
return 0;
exit_free_candev:
free_candev(dev);
return err;
}
static int grcan_probe(struct platform_device *ofdev)
{
struct device_node *np = ofdev->dev.of_node;
struct resource *res;
u32 sysid, ambafreq;
int irq, err;
void __iomem *base;
bool txbug = true;
/* Compare GRLIB version number with the first that does not
* have the tx bug (see start_xmit)
*/
err = of_property_read_u32(np, "systemid", &sysid);
if (!err && ((sysid & GRLIB_VERSION_MASK)
>= GRCAN_TXBUG_SAFE_GRLIB_VERSION))
txbug = false;
err = of_property_read_u32(np, "freq", &ambafreq);
if (err) {
dev_err(&ofdev->dev, "unable to fetch \"freq\" property\n");
goto exit_error;
}
res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(&ofdev->dev, res);
if (IS_ERR(base)) {
err = PTR_ERR(base);
goto exit_error;
}
irq = irq_of_parse_and_map(np, GRCAN_IRQIX_IRQ);
if (!irq) {
dev_err(&ofdev->dev, "no irq found\n");
err = -ENODEV;
goto exit_error;
}
grcan_sanitize_module_config(ofdev);
err = grcan_setup_netdev(ofdev, base, irq, ambafreq, txbug);
if (err)
goto exit_dispose_irq;
return 0;
exit_dispose_irq:
irq_dispose_mapping(irq);
exit_error:
dev_err(&ofdev->dev,
"%s socket CAN driver initialization failed with error %d\n",
DRV_NAME, err);
return err;
}
static int grcan_remove(struct platform_device *ofdev)
{
struct net_device *dev = platform_get_drvdata(ofdev);
struct grcan_priv *priv = netdev_priv(dev);
unregister_candev(dev); /* Will in turn call grcan_close */
irq_dispose_mapping(dev->irq);
netif_napi_del(&priv->napi);
free_candev(dev);
return 0;
}
static const struct of_device_id grcan_match[] = {
{.name = "GAISLER_GRCAN"},
{.name = "01_03d"},
{.name = "GAISLER_GRHCAN"},
{.name = "01_034"},
{},
};
MODULE_DEVICE_TABLE(of, grcan_match);
static struct platform_driver grcan_driver = {
.driver = {
.name = DRV_NAME,
.of_match_table = grcan_match,
},
.probe = grcan_probe,
.remove = grcan_remove,
};
module_platform_driver(grcan_driver);
MODULE_AUTHOR("Aeroflex Gaisler AB.");
MODULE_DESCRIPTION("Socket CAN driver for Aeroflex Gaisler GRCAN");
MODULE_LICENSE("GPL");
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