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Message-Id: <20230728075614.1014117-22-mkl@pengutronix.de>
Date: Fri, 28 Jul 2023 09:56:14 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
kuba@...nel.org,
linux-can@...r.kernel.org,
kernel@...gutronix.de,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net-next 21/21] can: gs_usb: convert to NAPI/rx-offload to avoid OoO reception
The driver used to pass received CAN frames/skbs to the network stack
with netif_rx(). In netif_rx() the skbs are queued to the local CPU.
If IRQs are handled in round robin, OoO packets may occur.
To avoid out-of-order reception convert the driver from netif_rx() to
NAPI.
For USB devices with timestamping support use the rx-offload helper
can_rx_offload_queue_timestamp() for the RX, and
can_rx_offload_get_echo_skb_queue_timestamp() for the TX path. Devices
without timestamping support use can_rx_offload_queue_tail() for RX,
and can_rx_offload_get_echo_skb_queue_tail() for the TX path.
Link: https://lore.kernel.org/all/559D628C.5020100@hartkopp.net
Link: https://github.com/candle-usb/candleLight_fw/issues/166
Link: https://lore.kernel.org/all/20230718-gs_usb-rx-offload-v2-3-716e542d14d5@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
drivers/net/can/usb/Kconfig | 1 +
drivers/net/can/usb/gs_usb.c | 85 ++++++++++++++++++++++++++++--------
2 files changed, 67 insertions(+), 19 deletions(-)
diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig
index 58fcd2b34820..d1450722cb3c 100644
--- a/drivers/net/can/usb/Kconfig
+++ b/drivers/net/can/usb/Kconfig
@@ -52,6 +52,7 @@ config CAN_F81604
config CAN_GS_USB
tristate "Geschwister Schneider UG and candleLight compatible interfaces"
+ select CAN_RX_OFFLOAD
help
This driver supports the Geschwister Schneider and
bytewerk.org candleLight compatible
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index 6caf3974e028..95b0fdb602c8 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -5,6 +5,7 @@
* Copyright (C) 2013-2016 Geschwister Schneider Technologie-,
* Entwicklungs- und Vertriebs UG (Haftungsbeschränkt).
* Copyright (C) 2016 Hubert Denkmair
+ * Copyright (c) 2023 Pengutronix, Marc Kleine-Budde <kernel@...gutronix.de>
*
* Many thanks to all socketcan devs!
*/
@@ -24,6 +25,7 @@
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
+#include <linux/can/rx-offload.h>
/* Device specific constants */
#define USB_GS_USB_1_VENDOR_ID 0x1d50
@@ -282,6 +284,8 @@ struct gs_host_frame {
#define GS_MAX_TX_URBS 10
/* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
#define GS_MAX_RX_URBS 30
+#define GS_NAPI_WEIGHT 32
+
/* Maximum number of interfaces the driver supports per device.
* Current hardware only supports 3 interfaces. The future may vary.
*/
@@ -295,6 +299,7 @@ struct gs_tx_context {
struct gs_can {
struct can_priv can; /* must be the first member */
+ struct can_rx_offload offload;
struct gs_usb *parent;
struct net_device *netdev;
@@ -506,20 +511,59 @@ static void gs_update_state(struct gs_can *dev, struct can_frame *cf)
}
}
-static void gs_usb_set_timestamp(struct gs_can *dev, struct sk_buff *skb,
- const struct gs_host_frame *hf)
+static u32 gs_usb_set_timestamp(struct gs_can *dev, struct sk_buff *skb,
+ const struct gs_host_frame *hf)
{
u32 timestamp;
- if (!(dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP))
- return;
-
if (hf->flags & GS_CAN_FLAG_FD)
timestamp = le32_to_cpu(hf->canfd_ts->timestamp_us);
else
timestamp = le32_to_cpu(hf->classic_can_ts->timestamp_us);
- gs_usb_skb_set_timestamp(dev, skb, timestamp);
+ if (skb)
+ gs_usb_skb_set_timestamp(dev, skb, timestamp);
+
+ return timestamp;
+}
+
+static void gs_usb_rx_offload(struct gs_can *dev, struct sk_buff *skb,
+ const struct gs_host_frame *hf)
+{
+ struct can_rx_offload *offload = &dev->offload;
+ int rc;
+
+ if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) {
+ const u32 ts = gs_usb_set_timestamp(dev, skb, hf);
+
+ rc = can_rx_offload_queue_timestamp(offload, skb, ts);
+ } else {
+ rc = can_rx_offload_queue_tail(offload, skb);
+ }
+
+ if (rc)
+ dev->netdev->stats.rx_fifo_errors++;
+}
+
+static unsigned int
+gs_usb_get_echo_skb(struct gs_can *dev, struct sk_buff *skb,
+ const struct gs_host_frame *hf)
+{
+ struct can_rx_offload *offload = &dev->offload;
+ const u32 echo_id = hf->echo_id;
+ unsigned int len;
+
+ if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) {
+ const u32 ts = gs_usb_set_timestamp(dev, skb, hf);
+
+ len = can_rx_offload_get_echo_skb_queue_timestamp(offload, echo_id,
+ ts, NULL);
+ } else {
+ len = can_rx_offload_get_echo_skb_queue_tail(offload, echo_id,
+ NULL);
+ }
+
+ return len;
}
static void gs_usb_receive_bulk_callback(struct urb *urb)
@@ -592,12 +636,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
gs_update_state(dev, cf);
}
- gs_usb_set_timestamp(dev, skb, hf);
-
- stats->rx_packets++;
- stats->rx_bytes += hf->can_dlc;
-
- netif_rx(skb);
+ gs_usb_rx_offload(dev, skb, hf);
} else { /* echo_id == hf->echo_id */
if (hf->echo_id >= GS_MAX_TX_URBS) {
netdev_err(netdev,
@@ -617,12 +656,8 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
}
skb = dev->can.echo_skb[hf->echo_id];
- gs_usb_set_timestamp(dev, skb, hf);
-
stats->tx_packets++;
- stats->tx_bytes += can_get_echo_skb(netdev, hf->echo_id,
- NULL);
-
+ stats->tx_bytes += gs_usb_get_echo_skb(dev, skb, hf);
gs_free_tx_context(txc);
atomic_dec(&dev->active_tx_urbs);
@@ -641,9 +676,12 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
cf->can_id |= CAN_ERR_CRTL;
cf->len = CAN_ERR_DLC;
cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
- netif_rx(skb);
+
+ gs_usb_rx_offload(dev, skb, hf);
}
+ can_rx_offload_irq_finish(&dev->offload);
+
resubmit_urb:
usb_fill_bulk_urb(urb, parent->udev,
usb_rcvbulkpipe(parent->udev, GS_USB_ENDPOINT_IN),
@@ -857,6 +895,8 @@ static int gs_can_open(struct net_device *netdev)
dev->hf_size_tx = struct_size(hf, classic_can, 1);
}
+ can_rx_offload_enable(&dev->offload);
+
if (!parent->active_channels) {
if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
gs_usb_timestamp_init(parent);
@@ -965,6 +1005,7 @@ static int gs_can_open(struct net_device *netdev)
gs_usb_timestamp_stop(parent);
}
+ can_rx_offload_disable(&dev->offload);
close_candev(netdev);
return rc;
@@ -1037,6 +1078,8 @@ static int gs_can_close(struct net_device *netdev)
dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
}
+ can_rx_offload_disable(&dev->offload);
+
/* close the netdev */
close_candev(netdev);
@@ -1336,6 +1379,7 @@ static struct gs_can *gs_make_candev(unsigned int channel,
dev->can.data_bittiming_const = &dev->data_bt_const;
}
+ can_rx_offload_add_manual(netdev, &dev->offload, GS_NAPI_WEIGHT);
SET_NETDEV_DEV(netdev, &intf->dev);
rc = register_candev(dev->netdev);
@@ -1343,11 +1387,13 @@ static struct gs_can *gs_make_candev(unsigned int channel,
dev_err(&intf->dev,
"Couldn't register candev for channel %d (%pe)\n",
channel, ERR_PTR(rc));
- goto out_free_candev;
+ goto out_can_rx_offload_del;
}
return dev;
+out_can_rx_offload_del:
+ can_rx_offload_del(&dev->offload);
out_free_candev:
free_candev(dev->netdev);
return ERR_PTR(rc);
@@ -1356,6 +1402,7 @@ static struct gs_can *gs_make_candev(unsigned int channel,
static void gs_destroy_candev(struct gs_can *dev)
{
unregister_candev(dev->netdev);
+ can_rx_offload_del(&dev->offload);
free_candev(dev->netdev);
}
--
2.40.1
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