// 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->len / 2; i++) { out_be16(data, *payload++); data += 2 + _MSCAN_RESERVED_DSR_SIZE; } /* write remaining byte if necessary */ if (frame->len & 1) out_8(data, frame->data[frame->len - 1]); } out_8(®s->tx.dlr, frame->len); 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, 0); /* 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->len = can_cc_dlc2len(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->len / 2; i++) { *payload++ = in_be16(data); data += 2 + _MSCAN_RESERVED_DSR_SIZE; } /* read remaining byte if necessary */ if (frame->len & 1) frame->data[frame->len - 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->len = 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); stats->rx_packets++; if (!(frame->can_id & CAN_RTR_FLAG)) stats->rx_bytes += frame->len; } else if (canrflg & MSCAN_ERR_IF) { mscan_get_err_frame(dev, frame, canrflg); } 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 += can_get_echo_skb(dev, entry->id, NULL); stats->tx_packets++; 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, }; static const struct ethtool_ops mscan_ethtool_ops = { .get_ts_info = ethtool_op_get_ts_info, }; 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->ethtool_ops = &mscan_ethtool_ops; dev->flags |= IFF_ECHO; /* we support local echo */ netif_napi_add_weight(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");