/*
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* Copyright (c) 2014 David Jander, Protonic Holland
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* Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the version 2 of the GNU General Public License
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* as published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/can/dev.h>
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#include <linux/can/rx-offload.h>
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struct can_rx_offload_cb {
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u32 timestamp;
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};
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static inline struct can_rx_offload_cb *can_rx_offload_get_cb(struct sk_buff *skb)
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{
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BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));
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return (struct can_rx_offload_cb *)skb->cb;
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}
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static inline bool can_rx_offload_le(struct can_rx_offload *offload, unsigned int a, unsigned int b)
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{
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if (offload->inc)
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return a <= b;
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else
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return a >= b;
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}
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static inline unsigned int can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val)
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{
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if (offload->inc)
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return (*val)++;
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else
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return (*val)--;
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}
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static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
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{
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struct can_rx_offload *offload = container_of(napi, struct can_rx_offload, napi);
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struct net_device *dev = offload->dev;
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struct net_device_stats *stats = &dev->stats;
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struct sk_buff *skb;
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int work_done = 0;
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while ((work_done < quota) &&
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(skb = skb_dequeue(&offload->skb_queue))) {
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struct can_frame *cf = (struct can_frame *)skb->data;
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work_done++;
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stats->rx_packets++;
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stats->rx_bytes += cf->can_dlc;
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netif_receive_skb(skb);
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}
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if (work_done < quota) {
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napi_complete_done(napi, work_done);
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/* Check if there was another interrupt */
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if (!skb_queue_empty(&offload->skb_queue))
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napi_reschedule(&offload->napi);
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}
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can_led_event(offload->dev, CAN_LED_EVENT_RX);
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return work_done;
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}
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static inline void __skb_queue_add_sort(struct sk_buff_head *head, struct sk_buff *new,
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int (*compare)(struct sk_buff *a, struct sk_buff *b))
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{
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struct sk_buff *pos, *insert = (struct sk_buff *)head;
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skb_queue_reverse_walk(head, pos) {
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const struct can_rx_offload_cb *cb_pos, *cb_new;
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cb_pos = can_rx_offload_get_cb(pos);
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cb_new = can_rx_offload_get_cb(new);
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netdev_dbg(new->dev,
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"%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n",
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__func__,
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cb_pos->timestamp, cb_new->timestamp,
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cb_new->timestamp - cb_pos->timestamp,
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skb_queue_len(head));
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if (compare(pos, new) < 0)
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continue;
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insert = pos;
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break;
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}
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__skb_queue_after(head, insert, new);
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}
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static int can_rx_offload_compare(struct sk_buff *a, struct sk_buff *b)
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{
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const struct can_rx_offload_cb *cb_a, *cb_b;
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cb_a = can_rx_offload_get_cb(a);
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cb_b = can_rx_offload_get_cb(b);
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/* Substract two u32 and return result as int, to keep
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* difference steady around the u32 overflow.
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*/
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return cb_b->timestamp - cb_a->timestamp;
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}
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/**
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* can_rx_offload_offload_one() - Read one CAN frame from HW
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* @offload: pointer to rx_offload context
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* @n: number of mailbox to read
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*
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* The task of this function is to read a CAN frame from mailbox @n
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* from the device and return the mailbox's content as a struct
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* sk_buff.
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*
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* If the struct can_rx_offload::skb_queue exceeds the maximal queue
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* length (struct can_rx_offload::skb_queue_len_max) or no skb can be
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* allocated, the mailbox contents is discarded by reading it into an
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* overflow buffer. This way the mailbox is marked as free by the
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* driver.
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*
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* Return: A pointer to skb containing the CAN frame on success.
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*
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* NULL if the mailbox @n is empty.
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*
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* ERR_PTR() in case of an error
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*/
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static struct sk_buff *
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can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
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{
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struct sk_buff *skb = NULL, *skb_error = NULL;
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struct can_rx_offload_cb *cb;
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struct can_frame *cf;
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int ret;
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if (likely(skb_queue_len(&offload->skb_queue) <
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offload->skb_queue_len_max)) {
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skb = alloc_can_skb(offload->dev, &cf);
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if (unlikely(!skb))
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skb_error = ERR_PTR(-ENOMEM); /* skb alloc failed */
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} else {
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skb_error = ERR_PTR(-ENOBUFS); /* skb_queue is full */
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}
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/* If queue is full or skb not available, drop by reading into
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* overflow buffer.
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*/
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if (unlikely(skb_error)) {
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struct can_frame cf_overflow;
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u32 timestamp;
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ret = offload->mailbox_read(offload, &cf_overflow,
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×tamp, n);
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/* Mailbox was empty. */
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if (unlikely(!ret))
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return NULL;
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/* Mailbox has been read and we're dropping it or
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* there was a problem reading the mailbox.
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*
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* Increment error counters in any case.
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*/
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offload->dev->stats.rx_dropped++;
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offload->dev->stats.rx_fifo_errors++;
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/* There was a problem reading the mailbox, propagate
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* error value.
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*/
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if (unlikely(ret < 0))
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return ERR_PTR(ret);
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return skb_error;
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}
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cb = can_rx_offload_get_cb(skb);
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ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
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/* Mailbox was empty. */
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if (unlikely(!ret)) {
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kfree_skb(skb);
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return NULL;
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}
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/* There was a problem reading the mailbox, propagate error value. */
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if (unlikely(ret < 0)) {
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kfree_skb(skb);
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offload->dev->stats.rx_dropped++;
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offload->dev->stats.rx_fifo_errors++;
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return ERR_PTR(ret);
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}
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/* Mailbox was read. */
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return skb;
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}
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int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
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{
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struct sk_buff_head skb_queue;
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unsigned int i;
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__skb_queue_head_init(&skb_queue);
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for (i = offload->mb_first;
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can_rx_offload_le(offload, i, offload->mb_last);
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can_rx_offload_inc(offload, &i)) {
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struct sk_buff *skb;
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if (!(pending & BIT_ULL(i)))
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continue;
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skb = can_rx_offload_offload_one(offload, i);
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if (IS_ERR_OR_NULL(skb))
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continue;
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__skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
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}
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if (!skb_queue_empty(&skb_queue)) {
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unsigned long flags;
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u32 queue_len;
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spin_lock_irqsave(&offload->skb_queue.lock, flags);
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skb_queue_splice_tail(&skb_queue, &offload->skb_queue);
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spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
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if ((queue_len = skb_queue_len(&offload->skb_queue)) >
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(offload->skb_queue_len_max / 8))
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netdev_dbg(offload->dev, "%s: queue_len=%d\n",
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__func__, queue_len);
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can_rx_offload_schedule(offload);
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}
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return skb_queue_len(&skb_queue);
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp);
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int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload)
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{
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struct sk_buff *skb;
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int received = 0;
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while (1) {
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skb = can_rx_offload_offload_one(offload, 0);
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if (IS_ERR(skb))
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continue;
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if (!skb)
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break;
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skb_queue_tail(&offload->skb_queue, skb);
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received++;
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}
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if (received)
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can_rx_offload_schedule(offload);
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return received;
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);
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int can_rx_offload_queue_sorted(struct can_rx_offload *offload,
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struct sk_buff *skb, u32 timestamp)
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{
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struct can_rx_offload_cb *cb;
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unsigned long flags;
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if (skb_queue_len(&offload->skb_queue) >
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offload->skb_queue_len_max) {
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dev_kfree_skb_any(skb);
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return -ENOBUFS;
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}
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cb = can_rx_offload_get_cb(skb);
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cb->timestamp = timestamp;
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spin_lock_irqsave(&offload->skb_queue.lock, flags);
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__skb_queue_add_sort(&offload->skb_queue, skb, can_rx_offload_compare);
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spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
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can_rx_offload_schedule(offload);
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return 0;
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_queue_sorted);
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unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
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unsigned int idx, u32 timestamp)
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{
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struct net_device *dev = offload->dev;
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struct net_device_stats *stats = &dev->stats;
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struct sk_buff *skb;
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u8 len;
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int err;
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skb = __can_get_echo_skb(dev, idx, &len);
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if (!skb)
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return 0;
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err = can_rx_offload_queue_sorted(offload, skb, timestamp);
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if (err) {
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stats->rx_errors++;
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stats->tx_fifo_errors++;
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}
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return len;
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb);
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int can_rx_offload_queue_tail(struct can_rx_offload *offload,
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struct sk_buff *skb)
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{
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if (skb_queue_len(&offload->skb_queue) >
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offload->skb_queue_len_max) {
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dev_kfree_skb_any(skb);
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return -ENOBUFS;
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}
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skb_queue_tail(&offload->skb_queue, skb);
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can_rx_offload_schedule(offload);
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return 0;
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);
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static int can_rx_offload_init_queue(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
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{
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offload->dev = dev;
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/* Limit queue len to 4x the weight (rounted to next power of two) */
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offload->skb_queue_len_max = 2 << fls(weight);
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offload->skb_queue_len_max *= 4;
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skb_queue_head_init(&offload->skb_queue);
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can_rx_offload_reset(offload);
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netif_napi_add(dev, &offload->napi, can_rx_offload_napi_poll, weight);
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dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n",
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__func__, offload->skb_queue_len_max);
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return 0;
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}
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int can_rx_offload_add_timestamp(struct net_device *dev, struct can_rx_offload *offload)
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{
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unsigned int weight;
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if (offload->mb_first > BITS_PER_LONG_LONG ||
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offload->mb_last > BITS_PER_LONG_LONG || !offload->mailbox_read)
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return -EINVAL;
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if (offload->mb_first < offload->mb_last) {
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offload->inc = true;
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weight = offload->mb_last - offload->mb_first;
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} else {
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offload->inc = false;
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weight = offload->mb_first - offload->mb_last;
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}
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return can_rx_offload_init_queue(dev, offload, weight);
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);
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int can_rx_offload_add_fifo(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
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{
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if (!offload->mailbox_read)
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return -EINVAL;
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return can_rx_offload_init_queue(dev, offload, weight);
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);
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void can_rx_offload_enable(struct can_rx_offload *offload)
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{
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can_rx_offload_reset(offload);
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napi_enable(&offload->napi);
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_enable);
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void can_rx_offload_del(struct can_rx_offload *offload)
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{
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netif_napi_del(&offload->napi);
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skb_queue_purge(&offload->skb_queue);
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_del);
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void can_rx_offload_reset(struct can_rx_offload *offload)
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{
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}
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EXPORT_SYMBOL_GPL(can_rx_offload_reset);
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