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authorDavid Jander <david@protonic.nl>2014-10-10 17:30:10 +0200
committerMarc Kleine-Budde <mkl@pengutronix.de>2017-02-06 15:13:23 +0100
commitd254586c34538c0014280806c5d4795697cf21e5 (patch)
treeecce05b11eb440dc8bfc211de75304cd977ebbf9 /drivers/net/can
parentbd092ad1463ca0990581fa992e12a9b0ed295d25 (diff)
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>
Diffstat (limited to 'drivers/net/can')
-rw-r--r--drivers/net/can/Makefile3
-rw-r--r--drivers/net/can/rx-offload.c156
2 files changed, 158 insertions, 1 deletions
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index 7a85495dbb0c..0da4f2f5c7e3 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -6,7 +6,8 @@ obj-$(CONFIG_CAN_VCAN) += vcan.o
obj-$(CONFIG_CAN_SLCAN) += slcan.o
obj-$(CONFIG_CAN_DEV) += can-dev.o
-can-dev-y := dev.o
+can-dev-y += dev.o
+can-dev-y += rx-offload.o
can-dev-$(CONFIG_CAN_LEDS) += led.o
diff --git a/drivers/net/can/rx-offload.c b/drivers/net/can/rx-offload.c
new file mode 100644
index 000000000000..7267c61762c7
--- /dev/null
+++ b/drivers/net/can/rx-offload.c
@@ -0,0 +1,156 @@
+/*
+ * 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>
+
+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 struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
+{
+ struct sk_buff *skb = NULL;
+ 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;
+
+ ret = offload->mailbox_read(offload, &cf_overflow, n);
+ if (ret)
+ offload->dev->stats.rx_dropped++;
+
+ return NULL;
+ }
+
+ ret = offload->mailbox_read(offload, cf, n);
+ if (!ret) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ return skb;
+}
+
+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_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);