diff options
Diffstat (limited to 'drivers/net/can/grcan.c')
| -rw-r--r-- | drivers/net/can/grcan.c | 1756 |
1 files changed, 1756 insertions, 0 deletions
diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c new file mode 100644 index 0000000..17fbc7a --- /dev/null +++ b/drivers/net/can/grcan.c @@ -0,0 +1,1756 @@ +/* + * 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/kernel-parameters.txt" 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 <asm/prom.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(®s->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(®s->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(®s->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(®s->conf); + + grcan_set_bits(®s->ctrl, GRCAN_CTRL_RESET); + grcan_write_reg(®s->conf, config); + + priv->eskbp = grcan_read_reg(®s->txrd); + priv->can.state = CAN_STATE_STOPPED; + + /* Turn off hardware filtering - regs->rxcode set to 0 by reset */ + grcan_write_reg(®s->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(®s->imr, GRCAN_IRQ_NONE); + grcan_clear_bits(®s->txctrl, GRCAN_TXCTRL_ENABLE); + grcan_clear_bits(®s->rxctrl, GRCAN_RXCTRL_ENABLE); + grcan_clear_bits(®s->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(®s->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(®s->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(®s->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(®s->txrd); + txrd = grcan_ring_add(txrd, GRCAN_MSG_SIZE, dma->tx.size); + grcan_write_reg(®s->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(®s->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(®s->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(®s->pimsr); + if (!sources) + return IRQ_NONE; + grcan_write_reg(®s->picr, sources); + status = grcan_read_reg(®s->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(®s->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(unsigned long data) +{ + struct net_device *dev = (struct net_device *)data; + struct grcan_priv *priv = netdev_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(®s->imr); + + u32 txaddr = grcan_read_reg(®s->txaddr); + u32 txsize = grcan_read_reg(®s->txsize); + u32 txwr = grcan_read_reg(®s->txwr); + u32 txrd = grcan_read_reg(®s->txrd); + u32 eskbp = priv->eskbp; + + u32 rxaddr = grcan_read_reg(®s->rxaddr); + u32 rxsize = grcan_read_reg(®s->rxsize); + u32 rxwr = grcan_read_reg(®s->rxwr); + u32 rxrd = grcan_read_reg(®s->rxrd); + + grcan_reset(dev); + + /* Restore */ + grcan_write_reg(®s->txaddr, txaddr); + grcan_write_reg(®s->txsize, txsize); + grcan_write_reg(®s->txwr, txwr); + grcan_write_reg(®s->txrd, txrd); + priv->eskbp = eskbp; + + grcan_write_reg(®s->rxaddr, rxaddr); + grcan_write_reg(®s->rxsize, rxsize); + grcan_write_reg(®s->rxwr, rxwr); + grcan_write_reg(®s->rxrd, rxrd); + + /* Turn on device again */ + grcan_write_reg(®s->imr, imr); + priv->can.state = CAN_STATE_ERROR_ACTIVE; + grcan_write_reg(®s->txctrl, GRCAN_TXCTRL_ENABLE + | (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT + ? GRCAN_TXCTRL_SINGLE : 0)); + grcan_write_reg(®s->rxctrl, GRCAN_RXCTRL_ENABLE); + grcan_write_reg(®s->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(unsigned long data) +{ + struct net_device *dev = (struct net_device *)data; + struct grcan_priv *priv = netdev_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(®s->txctrl, GRCAN_TXCTRL_ENABLE); + grcan_clear_bits(®s->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(®s->txaddr, priv->dma.tx.handle); + grcan_write_reg(®s->txsize, priv->dma.tx.size); + /* regs->txwr, regs->txrd and priv->eskbp already set to 0 by reset */ + + grcan_write_reg(®s->rxaddr, priv->dma.rx.handle); + grcan_write_reg(®s->rxsize, priv->dma.rx.size); + /* regs->rxwr and regs->rxrd already set to 0 by reset */ + + /* Enable interrupts */ + grcan_read_reg(®s->pir); + grcan_write_reg(®s->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(®s->conf, confop, GRCAN_CONF_OPERATION); + txctrl = GRCAN_TXCTRL_ENABLE + | (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT + ? GRCAN_TXCTRL_SINGLE : 0); + grcan_write_reg(®s->txctrl, txctrl); + grcan_write_reg(®s->rxctrl, GRCAN_RXCTRL_ENABLE); + grcan_write_reg(®s->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 = kzalloc(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 = kzalloc(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(®s->rxrd); + startrd = rd; + for (work_done = 0; work_done < budget; work_done++) { + /* Check for packet to receive */ + wr = grcan_read_reg(®s->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); + } + } + netif_receive_skb(skb); + + /* Update statistics and read pointer */ + stats->rx_packets++; + stats->rx_bytes += cf->can_dlc; + 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(®s->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(®s->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(®s->txctrl, GRCAN_TXCTRL_ONGOING) || + grcan_read_reg(®s->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(®s->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(®s->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(®s->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(®s->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, S_IRUGO); \ + 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, S_IRUGO | S_IWUSR, \ + 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, +}; + +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(®s->ctrl, GRCAN_CTRL_RESET); + grcan_set_bits(®s->conf, GRCAN_CONF_SAM); + if (grcan_read_bits(®s->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) { + init_timer(&priv->rr_timer); + priv->rr_timer.function = grcan_running_reset; + priv->rr_timer.data = (unsigned long)dev; + + init_timer(&priv->hang_timer); + priv->hang_timer.function = grcan_initiate_running_reset; + priv->hang_timer.data = (unsigned long)dev; + } + + 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; + + dev_set_drvdata(&ofdev->dev, 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(®s->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_request_and_ioremap(&ofdev->dev, res); + if (!base) { + dev_err(&ofdev->dev, "couldn't map IO resource\n"); + err = -EADDRNOTAVAIL; + 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 = dev_get_drvdata(&ofdev->dev); + struct grcan_priv *priv = netdev_priv(dev); + + unregister_candev(dev); /* Will in turn call grcan_close */ + + irq_dispose_mapping(dev->irq); + dev_set_drvdata(&ofdev->dev, NULL); + netif_napi_del(&priv->napi); + free_candev(dev); + + return 0; +} + +static 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, + .owner = THIS_MODULE, + .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"); |
