can: rx-offload: Add support for HW fifo based irq offloading
Some CAN controllers have a usable FIFO already but can still benefit from off-loading the CAN controller FIFO. The CAN frames of the FIFO are read and put into a skb queue during interrupt and then transmitted in a NAPI context. Signed-off-by: David Jander <david@protonic.nl> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>hifive-unleashed-5.1
David Jander
Marc Kleine-Budde
parent
bd092ad146
commit
d254586c34
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@ -6,7 +6,8 @@ obj-$(CONFIG_CAN_VCAN) += vcan.o
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obj-$(CONFIG_CAN_SLCAN) += slcan.o
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obj-$(CONFIG_CAN_DEV) += can-dev.o
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can-dev-y := dev.o
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can-dev-y += dev.o
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can-dev-y += rx-offload.o
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can-dev-$(CONFIG_CAN_LEDS) += led.o
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@ -0,0 +1,156 @@
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/*
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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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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 struct sk_buff *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;
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struct can_frame *cf;
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int ret;
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/* If queue is full or skb not available, read to discard mailbox */
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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 (!skb) {
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struct can_frame cf_overflow;
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ret = offload->mailbox_read(offload, &cf_overflow, n);
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if (ret)
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offload->dev->stats.rx_dropped++;
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return NULL;
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}
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ret = offload->mailbox_read(offload, cf, n);
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if (!ret) {
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kfree_skb(skb);
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return NULL;
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}
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return skb;
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}
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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 ((skb = can_rx_offload_offload_one(offload, 0))) {
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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_irq_queue_err_skb(struct can_rx_offload *offload, 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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return -ENOMEM;
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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_irq_queue_err_skb);
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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_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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@ -0,0 +1,51 @@
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/*
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* linux/can/rx-offload.h
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*
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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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#ifndef _CAN_RX_OFFLOAD_H
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#define _CAN_RX_OFFLOAD_H
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#include <linux/netdevice.h>
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#include <linux/can.h>
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struct can_rx_offload {
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struct net_device *dev;
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unsigned int (*mailbox_read)(struct can_rx_offload *offload, struct can_frame *cf, unsigned int mb);
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struct sk_buff_head skb_queue;
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u32 skb_queue_len_max;
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struct napi_struct napi;
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};
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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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int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload);
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int can_rx_offload_irq_queue_err_skb(struct can_rx_offload *offload, struct sk_buff *skb);
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void can_rx_offload_reset(struct can_rx_offload *offload);
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void can_rx_offload_del(struct can_rx_offload *offload);
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void can_rx_offload_enable(struct can_rx_offload *offload);
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static inline void can_rx_offload_schedule(struct can_rx_offload *offload)
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{
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napi_schedule(&offload->napi);
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}
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static inline void can_rx_offload_disable(struct can_rx_offload *offload)
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{
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napi_disable(&offload->napi);
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}
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#endif /* !_CAN_RX_OFFLOAD_H */
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