diff options
Diffstat (limited to 'drivers/net/can/mscan/mscan.c')
| -rw-r--r-- | drivers/net/can/mscan/mscan.c | 698 |
1 files changed, 698 insertions, 0 deletions
diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c new file mode 100644 index 000000000..640ba1b35 --- /dev/null +++ b/drivers/net/can/mscan/mscan.c @@ -0,0 +1,698 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * CAN bus driver for the alone generic (as possible as) MSCAN controller. + * + * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>, + * Varma Electronics Oy + * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com> + * Copyright (C) 2008-2009 Pengutronix <kernel@pengutronix.de> + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/netdevice.h> +#include <linux/if_arp.h> +#include <linux/if_ether.h> +#include <linux/list.h> +#include <linux/can/dev.h> +#include <linux/can/error.h> +#include <linux/io.h> + +#include "mscan.h" + +static const struct can_bittiming_const mscan_bittiming_const = { + .name = "mscan", + .tseg1_min = 4, + .tseg1_max = 16, + .tseg2_min = 2, + .tseg2_max = 8, + .sjw_max = 4, + .brp_min = 1, + .brp_max = 64, + .brp_inc = 1, +}; + +struct mscan_state { + u8 mode; + u8 canrier; + u8 cantier; +}; + +static enum can_state state_map[] = { + CAN_STATE_ERROR_ACTIVE, + CAN_STATE_ERROR_WARNING, + CAN_STATE_ERROR_PASSIVE, + CAN_STATE_BUS_OFF +}; + +static int mscan_set_mode(struct net_device *dev, u8 mode) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + int ret = 0; + int i; + u8 canctl1; + + if (mode != MSCAN_NORMAL_MODE) { + if (priv->tx_active) { + /* Abort transfers before going to sleep */# + out_8(®s->cantarq, priv->tx_active); + /* Suppress TX done interrupts */ + out_8(®s->cantier, 0); + } + + canctl1 = in_8(®s->canctl1); + if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) { + setbits8(®s->canctl0, MSCAN_SLPRQ); + for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) { + if (in_8(®s->canctl1) & MSCAN_SLPAK) + break; + udelay(100); + } + /* + * The mscan controller will fail to enter sleep mode, + * while there are irregular activities on bus, like + * somebody keeps retransmitting. This behavior is + * undocumented and seems to differ between mscan built + * in mpc5200b and mpc5200. We proceed in that case, + * since otherwise the slprq will be kept set and the + * controller will get stuck. NOTE: INITRQ or CSWAI + * will abort all active transmit actions, if still + * any, at once. + */ + if (i >= MSCAN_SET_MODE_RETRIES) + netdev_dbg(dev, + "device failed to enter sleep mode. " + "We proceed anyhow.\n"); + else + priv->can.state = CAN_STATE_SLEEPING; + } + + if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) { + setbits8(®s->canctl0, MSCAN_INITRQ); + for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) { + if (in_8(®s->canctl1) & MSCAN_INITAK) + break; + } + if (i >= MSCAN_SET_MODE_RETRIES) + ret = -ENODEV; + } + if (!ret) + priv->can.state = CAN_STATE_STOPPED; + + if (mode & MSCAN_CSWAI) + setbits8(®s->canctl0, MSCAN_CSWAI); + + } else { + canctl1 = in_8(®s->canctl1); + if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) { + clrbits8(®s->canctl0, MSCAN_SLPRQ | MSCAN_INITRQ); + for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) { + canctl1 = in_8(®s->canctl1); + if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK))) + break; + } + if (i >= MSCAN_SET_MODE_RETRIES) + ret = -ENODEV; + else + priv->can.state = CAN_STATE_ERROR_ACTIVE; + } + } + return ret; +} + +static int mscan_start(struct net_device *dev) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + u8 canrflg; + int err; + + out_8(®s->canrier, 0); + + INIT_LIST_HEAD(&priv->tx_head); + priv->prev_buf_id = 0; + priv->cur_pri = 0; + priv->tx_active = 0; + priv->shadow_canrier = 0; + priv->flags = 0; + + if (priv->type == MSCAN_TYPE_MPC5121) { + /* Clear pending bus-off condition */ + if (in_8(®s->canmisc) & MSCAN_BOHOLD) + out_8(®s->canmisc, MSCAN_BOHOLD); + } + + err = mscan_set_mode(dev, MSCAN_NORMAL_MODE); + if (err) + return err; + + canrflg = in_8(®s->canrflg); + priv->shadow_statflg = canrflg & MSCAN_STAT_MSK; + priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg), + MSCAN_STATE_TX(canrflg))]; + out_8(®s->cantier, 0); + + /* Enable receive interrupts. */ + out_8(®s->canrier, MSCAN_RX_INTS_ENABLE); + + return 0; +} + +static int mscan_restart(struct net_device *dev) +{ + struct mscan_priv *priv = netdev_priv(dev); + + if (priv->type == MSCAN_TYPE_MPC5121) { + struct mscan_regs __iomem *regs = priv->reg_base; + + priv->can.state = CAN_STATE_ERROR_ACTIVE; + WARN(!(in_8(®s->canmisc) & MSCAN_BOHOLD), + "bus-off state expected\n"); + out_8(®s->canmisc, MSCAN_BOHOLD); + /* Re-enable receive interrupts. */ + out_8(®s->canrier, MSCAN_RX_INTS_ENABLE); + } else { + if (priv->can.state <= CAN_STATE_BUS_OFF) + mscan_set_mode(dev, MSCAN_INIT_MODE); + return mscan_start(dev); + } + + return 0; +} + +static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct can_frame *frame = (struct can_frame *)skb->data; + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + int i, rtr, buf_id; + u32 can_id; + + if (can_dropped_invalid_skb(dev, skb)) + return NETDEV_TX_OK; + + out_8(®s->cantier, 0); + + i = ~priv->tx_active & MSCAN_TXE; + buf_id = ffs(i) - 1; + switch (hweight8(i)) { + case 0: + netif_stop_queue(dev); + netdev_err(dev, "Tx Ring full when queue awake!\n"); + return NETDEV_TX_BUSY; + case 1: + /* + * if buf_id < 3, then current frame will be send out of order, + * since buffer with lower id have higher priority (hell..) + */ + netif_stop_queue(dev); + fallthrough; + case 2: + if (buf_id < priv->prev_buf_id) { + priv->cur_pri++; + if (priv->cur_pri == 0xff) { + set_bit(F_TX_WAIT_ALL, &priv->flags); + netif_stop_queue(dev); + } + } + set_bit(F_TX_PROGRESS, &priv->flags); + break; + } + priv->prev_buf_id = buf_id; + out_8(®s->cantbsel, i); + + rtr = frame->can_id & CAN_RTR_FLAG; + + /* RTR is always the lowest bit of interest, then IDs follow */ + if (frame->can_id & CAN_EFF_FLAG) { + can_id = (frame->can_id & CAN_EFF_MASK) + << (MSCAN_EFF_RTR_SHIFT + 1); + if (rtr) + can_id |= 1 << MSCAN_EFF_RTR_SHIFT; + out_be16(®s->tx.idr3_2, can_id); + + can_id >>= 16; + /* EFF_FLAGS are between the IDs :( */ + can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0) + | MSCAN_EFF_FLAGS; + } else { + can_id = (frame->can_id & CAN_SFF_MASK) + << (MSCAN_SFF_RTR_SHIFT + 1); + if (rtr) + can_id |= 1 << MSCAN_SFF_RTR_SHIFT; + } + out_be16(®s->tx.idr1_0, can_id); + + if (!rtr) { + void __iomem *data = ®s->tx.dsr1_0; + u16 *payload = (u16 *)frame->data; + + for (i = 0; i < frame->can_dlc / 2; i++) { + out_be16(data, *payload++); + data += 2 + _MSCAN_RESERVED_DSR_SIZE; + } + /* write remaining byte if necessary */ + if (frame->can_dlc & 1) + out_8(data, frame->data[frame->can_dlc - 1]); + } + + out_8(®s->tx.dlr, frame->can_dlc); + out_8(®s->tx.tbpr, priv->cur_pri); + + /* Start transmission. */ + out_8(®s->cantflg, 1 << buf_id); + + if (!test_bit(F_TX_PROGRESS, &priv->flags)) + netif_trans_update(dev); + + list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head); + + can_put_echo_skb(skb, dev, buf_id); + + /* Enable interrupt. */ + priv->tx_active |= 1 << buf_id; + out_8(®s->cantier, priv->tx_active); + + return NETDEV_TX_OK; +} + +static enum can_state get_new_state(struct net_device *dev, u8 canrflg) +{ + struct mscan_priv *priv = netdev_priv(dev); + + if (unlikely(canrflg & MSCAN_CSCIF)) + return state_map[max(MSCAN_STATE_RX(canrflg), + MSCAN_STATE_TX(canrflg))]; + + return priv->can.state; +} + +static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + u32 can_id; + int i; + + can_id = in_be16(®s->rx.idr1_0); + if (can_id & (1 << 3)) { + frame->can_id = CAN_EFF_FLAG; + can_id = ((can_id << 16) | in_be16(®s->rx.idr3_2)); + can_id = ((can_id & 0xffe00000) | + ((can_id & 0x7ffff) << 2)) >> 2; + } else { + can_id >>= 4; + frame->can_id = 0; + } + + frame->can_id |= can_id >> 1; + if (can_id & 1) + frame->can_id |= CAN_RTR_FLAG; + + frame->can_dlc = get_can_dlc(in_8(®s->rx.dlr) & 0xf); + + if (!(frame->can_id & CAN_RTR_FLAG)) { + void __iomem *data = ®s->rx.dsr1_0; + u16 *payload = (u16 *)frame->data; + + for (i = 0; i < frame->can_dlc / 2; i++) { + *payload++ = in_be16(data); + data += 2 + _MSCAN_RESERVED_DSR_SIZE; + } + /* read remaining byte if necessary */ + if (frame->can_dlc & 1) + frame->data[frame->can_dlc - 1] = in_8(data); + } + + out_8(®s->canrflg, MSCAN_RXF); +} + +static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame, + u8 canrflg) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + struct net_device_stats *stats = &dev->stats; + enum can_state new_state; + + netdev_dbg(dev, "error interrupt (canrflg=%#x)\n", canrflg); + frame->can_id = CAN_ERR_FLAG; + + if (canrflg & MSCAN_OVRIF) { + frame->can_id |= CAN_ERR_CRTL; + frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW; + stats->rx_over_errors++; + stats->rx_errors++; + } else { + frame->data[1] = 0; + } + + new_state = get_new_state(dev, canrflg); + if (new_state != priv->can.state) { + can_change_state(dev, frame, + state_map[MSCAN_STATE_TX(canrflg)], + state_map[MSCAN_STATE_RX(canrflg)]); + + if (priv->can.state == CAN_STATE_BUS_OFF) { + /* + * The MSCAN on the MPC5200 does recover from bus-off + * automatically. To avoid that we stop the chip doing + * a light-weight stop (we are in irq-context). + */ + if (priv->type != MSCAN_TYPE_MPC5121) { + out_8(®s->cantier, 0); + out_8(®s->canrier, 0); + setbits8(®s->canctl0, + MSCAN_SLPRQ | MSCAN_INITRQ); + } + can_bus_off(dev); + } + } + priv->shadow_statflg = canrflg & MSCAN_STAT_MSK; + frame->can_dlc = CAN_ERR_DLC; + out_8(®s->canrflg, MSCAN_ERR_IF); +} + +static int mscan_rx_poll(struct napi_struct *napi, int quota) +{ + struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi); + struct net_device *dev = napi->dev; + struct mscan_regs __iomem *regs = priv->reg_base; + struct net_device_stats *stats = &dev->stats; + int work_done = 0; + struct sk_buff *skb; + struct can_frame *frame; + u8 canrflg; + + while (work_done < quota) { + canrflg = in_8(®s->canrflg); + if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF))) + break; + + skb = alloc_can_skb(dev, &frame); + if (!skb) { + if (printk_ratelimit()) + netdev_notice(dev, "packet dropped\n"); + stats->rx_dropped++; + out_8(®s->canrflg, canrflg); + continue; + } + + if (canrflg & MSCAN_RXF) + mscan_get_rx_frame(dev, frame); + else if (canrflg & MSCAN_ERR_IF) + mscan_get_err_frame(dev, frame, canrflg); + + stats->rx_packets++; + stats->rx_bytes += frame->can_dlc; + work_done++; + netif_receive_skb(skb); + } + + if (work_done < quota) { + if (likely(napi_complete_done(&priv->napi, work_done))) { + clear_bit(F_RX_PROGRESS, &priv->flags); + if (priv->can.state < CAN_STATE_BUS_OFF) + out_8(®s->canrier, priv->shadow_canrier); + } + } + return work_done; +} + +static irqreturn_t mscan_isr(int irq, void *dev_id) +{ + struct net_device *dev = (struct net_device *)dev_id; + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + struct net_device_stats *stats = &dev->stats; + u8 cantier, cantflg, canrflg; + irqreturn_t ret = IRQ_NONE; + + cantier = in_8(®s->cantier) & MSCAN_TXE; + cantflg = in_8(®s->cantflg) & cantier; + + if (cantier && cantflg) { + struct list_head *tmp, *pos; + + list_for_each_safe(pos, tmp, &priv->tx_head) { + struct tx_queue_entry *entry = + list_entry(pos, struct tx_queue_entry, list); + u8 mask = entry->mask; + + if (!(cantflg & mask)) + continue; + + out_8(®s->cantbsel, mask); + stats->tx_bytes += in_8(®s->tx.dlr); + stats->tx_packets++; + can_get_echo_skb(dev, entry->id); + priv->tx_active &= ~mask; + list_del(pos); + } + + if (list_empty(&priv->tx_head)) { + clear_bit(F_TX_WAIT_ALL, &priv->flags); + clear_bit(F_TX_PROGRESS, &priv->flags); + priv->cur_pri = 0; + } else { + netif_trans_update(dev); + } + + if (!test_bit(F_TX_WAIT_ALL, &priv->flags)) + netif_wake_queue(dev); + + out_8(®s->cantier, priv->tx_active); + ret = IRQ_HANDLED; + } + + canrflg = in_8(®s->canrflg); + if ((canrflg & ~MSCAN_STAT_MSK) && + !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) { + if (canrflg & ~MSCAN_STAT_MSK) { + priv->shadow_canrier = in_8(®s->canrier); + out_8(®s->canrier, 0); + napi_schedule(&priv->napi); + ret = IRQ_HANDLED; + } else { + clear_bit(F_RX_PROGRESS, &priv->flags); + } + } + return ret; +} + +static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode) +{ + int ret = 0; + + switch (mode) { + case CAN_MODE_START: + ret = mscan_restart(dev); + if (ret) + break; + if (netif_queue_stopped(dev)) + netif_wake_queue(dev); + break; + + default: + ret = -EOPNOTSUPP; + break; + } + return ret; +} + +static int mscan_do_set_bittiming(struct net_device *dev) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + struct can_bittiming *bt = &priv->can.bittiming; + u8 btr0, btr1; + + btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw); + btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) | + BTR1_SET_TSEG2(bt->phase_seg2) | + BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)); + + netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1); + + out_8(®s->canbtr0, btr0); + out_8(®s->canbtr1, btr1); + + return 0; +} + +static int mscan_get_berr_counter(const struct net_device *dev, + struct can_berr_counter *bec) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + + bec->txerr = in_8(®s->cantxerr); + bec->rxerr = in_8(®s->canrxerr); + + return 0; +} + +static int mscan_open(struct net_device *dev) +{ + int ret; + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + + ret = clk_prepare_enable(priv->clk_ipg); + if (ret) + goto exit_retcode; + ret = clk_prepare_enable(priv->clk_can); + if (ret) + goto exit_dis_ipg_clock; + + /* common open */ + ret = open_candev(dev); + if (ret) + goto exit_dis_can_clock; + + napi_enable(&priv->napi); + + ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev); + if (ret < 0) { + netdev_err(dev, "failed to attach interrupt\n"); + goto exit_napi_disable; + } + + if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) + setbits8(®s->canctl1, MSCAN_LISTEN); + else + clrbits8(®s->canctl1, MSCAN_LISTEN); + + ret = mscan_start(dev); + if (ret) + goto exit_free_irq; + + netif_start_queue(dev); + + return 0; + +exit_free_irq: + free_irq(dev->irq, dev); +exit_napi_disable: + napi_disable(&priv->napi); + close_candev(dev); +exit_dis_can_clock: + clk_disable_unprepare(priv->clk_can); +exit_dis_ipg_clock: + clk_disable_unprepare(priv->clk_ipg); +exit_retcode: + return ret; +} + +static int mscan_close(struct net_device *dev) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + + netif_stop_queue(dev); + napi_disable(&priv->napi); + + out_8(®s->cantier, 0); + out_8(®s->canrier, 0); + mscan_set_mode(dev, MSCAN_INIT_MODE); + close_candev(dev); + free_irq(dev->irq, dev); + + clk_disable_unprepare(priv->clk_can); + clk_disable_unprepare(priv->clk_ipg); + + return 0; +} + +static const struct net_device_ops mscan_netdev_ops = { + .ndo_open = mscan_open, + .ndo_stop = mscan_close, + .ndo_start_xmit = mscan_start_xmit, + .ndo_change_mtu = can_change_mtu, +}; + +int register_mscandev(struct net_device *dev, int mscan_clksrc) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + u8 ctl1; + + ctl1 = in_8(®s->canctl1); + if (mscan_clksrc) + ctl1 |= MSCAN_CLKSRC; + else + ctl1 &= ~MSCAN_CLKSRC; + + if (priv->type == MSCAN_TYPE_MPC5121) { + priv->can.do_get_berr_counter = mscan_get_berr_counter; + ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */ + } + + ctl1 |= MSCAN_CANE; + out_8(®s->canctl1, ctl1); + udelay(100); + + /* acceptance mask/acceptance code (accept everything) */ + out_be16(®s->canidar1_0, 0); + out_be16(®s->canidar3_2, 0); + out_be16(®s->canidar5_4, 0); + out_be16(®s->canidar7_6, 0); + + out_be16(®s->canidmr1_0, 0xffff); + out_be16(®s->canidmr3_2, 0xffff); + out_be16(®s->canidmr5_4, 0xffff); + out_be16(®s->canidmr7_6, 0xffff); + /* Two 32 bit Acceptance Filters */ + out_8(®s->canidac, MSCAN_AF_32BIT); + + mscan_set_mode(dev, MSCAN_INIT_MODE); + + return register_candev(dev); +} + +void unregister_mscandev(struct net_device *dev) +{ + struct mscan_priv *priv = netdev_priv(dev); + struct mscan_regs __iomem *regs = priv->reg_base; + mscan_set_mode(dev, MSCAN_INIT_MODE); + clrbits8(®s->canctl1, MSCAN_CANE); + unregister_candev(dev); +} + +struct net_device *alloc_mscandev(void) +{ + struct net_device *dev; + struct mscan_priv *priv; + int i; + + dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX); + if (!dev) + return NULL; + priv = netdev_priv(dev); + + dev->netdev_ops = &mscan_netdev_ops; + + dev->flags |= IFF_ECHO; /* we support local echo */ + + netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8); + + priv->can.bittiming_const = &mscan_bittiming_const; + priv->can.do_set_bittiming = mscan_do_set_bittiming; + priv->can.do_set_mode = mscan_do_set_mode; + priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES | + CAN_CTRLMODE_LISTENONLY; + + for (i = 0; i < TX_QUEUE_SIZE; i++) { + priv->tx_queue[i].id = i; + priv->tx_queue[i].mask = 1 << i; + } + + return dev; +} + +MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips"); |