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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2014 Protonic Holland,
* David Jander
* Copyright (C) 2014-2021 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)
{
unsigned int i;
int received = 0;
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(&offload->skb_irq_queue, skb,
can_rx_offload_compare);
received++;
}
return received;
}
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_irq_queue, skb);
received++;
}
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;
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;
__skb_queue_add_sort(&offload->skb_irq_queue, skb,
can_rx_offload_compare);
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,
unsigned int *frame_len_ptr)
{
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, frame_len_ptr);
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_irq_queue, skb);
return 0;
}
EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);
void can_rx_offload_irq_finish(struct can_rx_offload *offload)
{
unsigned long flags;
int queue_len;
if (skb_queue_empty_lockless(&offload->skb_irq_queue))
return;
spin_lock_irqsave(&offload->skb_queue.lock, flags);
skb_queue_splice_tail_init(&offload->skb_irq_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);
napi_schedule(&offload->napi);
}
EXPORT_SYMBOL_GPL(can_rx_offload_irq_finish);
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);
__skb_queue_head_init(&offload->skb_irq_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);
__skb_queue_purge(&offload->skb_irq_queue);
}
EXPORT_SYMBOL_GPL(can_rx_offload_del);
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