/* * Copyright (c) 2014 David Jander, Protonic Holland * Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the version 2 of the GNU General Public License * as published by the Free Software Foundation * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see <http://www.gnu.org/licenses/>. */ #include <linux/can/dev.h> #include <linux/can/rx-offload.h> struct can_rx_offload_cb { u32 timestamp; }; static inline struct can_rx_offload_cb *can_rx_offload_get_cb(struct sk_buff *skb) { BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb)); return (struct can_rx_offload_cb *)skb->cb; } static inline bool can_rx_offload_le(struct can_rx_offload *offload, unsigned int a, unsigned int b) { if (offload->inc) return a <= b; else return a >= b; } static inline unsigned int can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val) { if (offload->inc) return (*val)++; else return (*val)--; } static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota) { struct can_rx_offload *offload = container_of(napi, struct can_rx_offload, napi); struct net_device *dev = offload->dev; struct net_device_stats *stats = &dev->stats; struct sk_buff *skb; int work_done = 0; while ((work_done < quota) && (skb = skb_dequeue(&offload->skb_queue))) { struct can_frame *cf = (struct can_frame *)skb->data; work_done++; stats->rx_packets++; stats->rx_bytes += cf->can_dlc; netif_receive_skb(skb); } if (work_done < quota) { napi_complete_done(napi, work_done); /* Check if there was another interrupt */ if (!skb_queue_empty(&offload->skb_queue)) napi_reschedule(&offload->napi); } can_led_event(offload->dev, CAN_LED_EVENT_RX); return work_done; } static inline void __skb_queue_add_sort(struct sk_buff_head *head, struct sk_buff *new, int (*compare)(struct sk_buff *a, struct sk_buff *b)) { struct sk_buff *pos, *insert = (struct sk_buff *)head; skb_queue_reverse_walk(head, pos) { const struct can_rx_offload_cb *cb_pos, *cb_new; cb_pos = can_rx_offload_get_cb(pos); cb_new = can_rx_offload_get_cb(new); netdev_dbg(new->dev, "%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n", __func__, cb_pos->timestamp, cb_new->timestamp, cb_new->timestamp - cb_pos->timestamp, skb_queue_len(head)); if (compare(pos, new) < 0) continue; insert = pos; break; } __skb_queue_after(head, insert, new); } static int can_rx_offload_compare(struct sk_buff *a, struct sk_buff *b) { const struct can_rx_offload_cb *cb_a, *cb_b; cb_a = can_rx_offload_get_cb(a); cb_b = can_rx_offload_get_cb(b); /* Substract two u32 and return result as int, to keep * difference steady around the u32 overflow. */ return cb_b->timestamp - cb_a->timestamp; } static struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n) { struct sk_buff *skb = NULL; struct can_rx_offload_cb *cb; struct can_frame *cf; int ret; /* If queue is full or skb not available, read to discard mailbox */ if (likely(skb_queue_len(&offload->skb_queue) <= offload->skb_queue_len_max)) skb = alloc_can_skb(offload->dev, &cf); if (!skb) { struct can_frame cf_overflow; u32 timestamp; ret = offload->mailbox_read(offload, &cf_overflow, ×tamp, n); if (ret) offload->dev->stats.rx_dropped++; return NULL; } cb = can_rx_offload_get_cb(skb); ret = offload->mailbox_read(offload, cf, &cb->timestamp, n); if (!ret) { kfree_skb(skb); return NULL; } return skb; } int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending) { struct sk_buff_head skb_queue; unsigned int i; __skb_queue_head_init(&skb_queue); for (i = offload->mb_first; can_rx_offload_le(offload, i, offload->mb_last); can_rx_offload_inc(offload, &i)) { struct sk_buff *skb; if (!(pending & BIT_ULL(i))) continue; skb = can_rx_offload_offload_one(offload, i); if (!skb) break; __skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare); } if (!skb_queue_empty(&skb_queue)) { unsigned long flags; u32 queue_len; spin_lock_irqsave(&offload->skb_queue.lock, flags); skb_queue_splice_tail(&skb_queue, &offload->skb_queue); spin_unlock_irqrestore(&offload->skb_queue.lock, flags); if ((queue_len = skb_queue_len(&offload->skb_queue)) > (offload->skb_queue_len_max / 8)) netdev_dbg(offload->dev, "%s: queue_len=%d\n", __func__, queue_len); can_rx_offload_schedule(offload); } return skb_queue_len(&skb_queue); } EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp); int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload) { struct sk_buff *skb; int received = 0; while ((skb = can_rx_offload_offload_one(offload, 0))) { skb_queue_tail(&offload->skb_queue, skb); received++; } if (received) can_rx_offload_schedule(offload); return received; } EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo); int can_rx_offload_irq_queue_err_skb(struct can_rx_offload *offload, struct sk_buff *skb) { if (skb_queue_len(&offload->skb_queue) > offload->skb_queue_len_max) return -ENOMEM; skb_queue_tail(&offload->skb_queue, skb); can_rx_offload_schedule(offload); return 0; } EXPORT_SYMBOL_GPL(can_rx_offload_irq_queue_err_skb); static int can_rx_offload_init_queue(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight) { offload->dev = dev; /* Limit queue len to 4x the weight (rounted to next power of two) */ offload->skb_queue_len_max = 2 << fls(weight); offload->skb_queue_len_max *= 4; skb_queue_head_init(&offload->skb_queue); can_rx_offload_reset(offload); netif_napi_add(dev, &offload->napi, can_rx_offload_napi_poll, weight); dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n", __func__, offload->skb_queue_len_max); return 0; } int can_rx_offload_add_timestamp(struct net_device *dev, struct can_rx_offload *offload) { unsigned int weight; if (offload->mb_first > BITS_PER_LONG_LONG || offload->mb_last > BITS_PER_LONG_LONG || !offload->mailbox_read) return -EINVAL; if (offload->mb_first < offload->mb_last) { offload->inc = true; weight = offload->mb_last - offload->mb_first; } else { offload->inc = false; weight = offload->mb_first - offload->mb_last; } return can_rx_offload_init_queue(dev, offload, weight);; } EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp); int can_rx_offload_add_fifo(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight) { if (!offload->mailbox_read) return -EINVAL; return can_rx_offload_init_queue(dev, offload, weight); } EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo); void can_rx_offload_enable(struct can_rx_offload *offload) { can_rx_offload_reset(offload); napi_enable(&offload->napi); } EXPORT_SYMBOL_GPL(can_rx_offload_enable); void can_rx_offload_del(struct can_rx_offload *offload) { netif_napi_del(&offload->napi); skb_queue_purge(&offload->skb_queue); } EXPORT_SYMBOL_GPL(can_rx_offload_del); void can_rx_offload_reset(struct can_rx_offload *offload) { } EXPORT_SYMBOL_GPL(can_rx_offload_reset);