--- /dev/null
+/*
+ * 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 __devinit 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 __devexit 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[] __devinitconst = {
+ {.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 = __devexit_p(grcan_remove),
+};
+
+module_platform_driver(grcan_driver);
+
+MODULE_AUTHOR("Aeroflex Gaisler AB.");
+MODULE_DESCRIPTION("Socket CAN driver for Aeroflex Gaisler GRCAN");
+MODULE_LICENSE("GPL");
projects / deliverable / linux.git / commitdiff
