diff options
Diffstat (limited to 'drivers/net/can/dev/rx-offload.c')
-rw-r--r-- | drivers/net/can/dev/rx-offload.c | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/drivers/net/can/dev/rx-offload.c b/drivers/net/can/dev/rx-offload.c new file mode 100644 index 000000000000..3c1912c0430b --- /dev/null +++ b/drivers/net/can/dev/rx-offload.c @@ -0,0 +1,376 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2014 Protonic Holland, + * David Jander + * Copyright (C) 2014-2017 Pengutronix, + * Marc Kleine-Budde <kernel@pengutronix.de> + */ + +#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->len; + 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 = NULL; + + 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; + } + if (!insert) + __skb_queue_head(head, new); + else + __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); + + /* Subtract two u32 and return result as int, to keep + * difference steady around the u32 overflow. + */ + return cb_b->timestamp - cb_a->timestamp; +} + +/** + * can_rx_offload_offload_one() - Read one CAN frame from HW + * @offload: pointer to rx_offload context + * @n: number of mailbox to read + * + * The task of this function is to read a CAN frame from mailbox @n + * from the device and return the mailbox's content as a struct + * sk_buff. + * + * If the struct can_rx_offload::skb_queue exceeds the maximal queue + * length (struct can_rx_offload::skb_queue_len_max) or no skb can be + * allocated, the mailbox contents is discarded by reading it into an + * overflow buffer. This way the mailbox is marked as free by the + * driver. + * + * Return: A pointer to skb containing the CAN frame on success. + * + * NULL if the mailbox @n is empty. + * + * ERR_PTR() in case of an error + */ +static struct sk_buff * +can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n) +{ + struct sk_buff *skb; + struct can_rx_offload_cb *cb; + bool drop = false; + u32 timestamp; + + /* If queue is full drop frame */ + if (unlikely(skb_queue_len(&offload->skb_queue) > + offload->skb_queue_len_max)) + drop = true; + + skb = offload->mailbox_read(offload, n, ×tamp, drop); + /* Mailbox was empty. */ + if (unlikely(!skb)) + return NULL; + + /* There was a problem reading the mailbox, propagate + * error value. + */ + if (IS_ERR(skb)) { + offload->dev->stats.rx_dropped++; + offload->dev->stats.rx_fifo_errors++; + + return skb; + } + + /* Mailbox was read. */ + cb = can_rx_offload_get_cb(skb); + cb->timestamp = timestamp; + + 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 (IS_ERR_OR_NULL(skb)) + continue; + + __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); + + queue_len = skb_queue_len(&offload->skb_queue); + if (queue_len > 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 (1) { + skb = can_rx_offload_offload_one(offload, 0); + if (IS_ERR(skb)) + continue; + if (!skb) + break; + + 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_queue_sorted(struct can_rx_offload *offload, + struct sk_buff *skb, u32 timestamp) +{ + struct can_rx_offload_cb *cb; + unsigned long flags; + + if (skb_queue_len(&offload->skb_queue) > + offload->skb_queue_len_max) { + dev_kfree_skb_any(skb); + return -ENOBUFS; + } + + cb = can_rx_offload_get_cb(skb); + cb->timestamp = timestamp; + + spin_lock_irqsave(&offload->skb_queue.lock, flags); + __skb_queue_add_sort(&offload->skb_queue, skb, can_rx_offload_compare); + spin_unlock_irqrestore(&offload->skb_queue.lock, flags); + + can_rx_offload_schedule(offload); + + return 0; +} +EXPORT_SYMBOL_GPL(can_rx_offload_queue_sorted); + +unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload, + unsigned int idx, u32 timestamp) +{ + struct net_device *dev = offload->dev; + struct net_device_stats *stats = &dev->stats; + struct sk_buff *skb; + u8 len; + int err; + + skb = __can_get_echo_skb(dev, idx, &len); + if (!skb) + return 0; + + err = can_rx_offload_queue_sorted(offload, skb, timestamp); + if (err) { + stats->rx_errors++; + stats->tx_fifo_errors++; + } + + return len; +} +EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb); + +int can_rx_offload_queue_tail(struct can_rx_offload *offload, + struct sk_buff *skb) +{ + if (skb_queue_len(&offload->skb_queue) > + offload->skb_queue_len_max) { + dev_kfree_skb_any(skb); + return -ENOBUFS; + } + + skb_queue_tail(&offload->skb_queue, skb); + can_rx_offload_schedule(offload); + + return 0; +} +EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail); + +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); + + 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); + +int can_rx_offload_add_manual(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_manual); + +void can_rx_offload_enable(struct can_rx_offload *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); |