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Message-Id: <20210330114559.1114855-21-mkl@pengutronix.de>
Date: Tue, 30 Mar 2021 13:45:40 +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,
Torin Cooper-Bennun <torin@...iluxsystems.com>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [net-next 20/39] can: m_can: fix periph RX path: use rx-offload to ensure skbs are sent from softirq context
From: Torin Cooper-Bennun <torin@...iluxsystems.com>
For peripheral devices, m_can sent skbs directly from a threaded irq
instead of from a softirq context, breaking the tcan4x5x peripheral
driver completely. This patch transitions the driver to use the
rx-offload helper for peripherals, ensuring the skbs are sent from the
correct context, with h/w timestamping to ensure correct ordering.
Link: https://lore.kernel.org/r/20210308102427.63916-4-torin@maxiluxsystems.com
Signed-off-by: Torin Cooper-Bennun <torin@...iluxsystems.com>
[mkl: m_can_class_register(): update error handling]
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
drivers/net/can/m_can/m_can.c | 121 +++++++++++++++++++++++++++++-----
drivers/net/can/m_can/m_can.h | 2 +
2 files changed, 107 insertions(+), 16 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 7df81e38b043..890ed826a355 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -457,6 +457,21 @@ static void m_can_clean(struct net_device *net)
}
}
+/* For peripherals, pass skb to rx-offload, which will push skb from
+ * napi. For non-peripherals, RX is done in napi already, so push
+ * directly. timestamp is used to ensure good skb ordering in
+ * rx-offload and is ignored for non-peripherals.
+*/
+static void m_can_receive_skb(struct m_can_classdev *cdev,
+ struct sk_buff *skb,
+ u32 timestamp)
+{
+ if (cdev->is_peripheral)
+ can_rx_offload_queue_sorted(&cdev->offload, skb, timestamp);
+ else
+ netif_receive_skb(skb);
+}
+
static void m_can_read_fifo(struct net_device *dev, u32 rxfs)
{
struct net_device_stats *stats = &dev->stats;
@@ -464,6 +479,7 @@ static void m_can_read_fifo(struct net_device *dev, u32 rxfs)
struct canfd_frame *cf;
struct sk_buff *skb;
u32 id, fgi, dlc;
+ u32 timestamp = 0;
int i;
/* calculate the fifo get index for where to read data */
@@ -512,7 +528,9 @@ static void m_can_read_fifo(struct net_device *dev, u32 rxfs)
stats->rx_packets++;
stats->rx_bytes += cf->len;
- netif_receive_skb(skb);
+ timestamp = FIELD_GET(RX_BUF_RXTS_MASK, dlc);
+
+ m_can_receive_skb(cdev, skb, timestamp);
}
static int m_can_do_rx_poll(struct net_device *dev, int quota)
@@ -543,9 +561,11 @@ static int m_can_do_rx_poll(struct net_device *dev, int quota)
static int m_can_handle_lost_msg(struct net_device *dev)
{
+ struct m_can_classdev *cdev = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
struct can_frame *frame;
+ u32 timestamp = 0;
netdev_err(dev, "msg lost in rxf0\n");
@@ -559,7 +579,10 @@ static int m_can_handle_lost_msg(struct net_device *dev)
frame->can_id |= CAN_ERR_CRTL;
frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
- netif_receive_skb(skb);
+ if (cdev->is_peripheral)
+ timestamp = m_can_get_timestamp(cdev);
+
+ m_can_receive_skb(cdev, skb, timestamp);
return 1;
}
@@ -571,6 +594,7 @@ static int m_can_handle_lec_err(struct net_device *dev,
struct net_device_stats *stats = &dev->stats;
struct can_frame *cf;
struct sk_buff *skb;
+ u32 timestamp = 0;
cdev->can.can_stats.bus_error++;
stats->rx_errors++;
@@ -616,7 +640,11 @@ static int m_can_handle_lec_err(struct net_device *dev,
stats->rx_packets++;
stats->rx_bytes += cf->len;
- netif_receive_skb(skb);
+
+ if (cdev->is_peripheral)
+ timestamp = m_can_get_timestamp(cdev);
+
+ m_can_receive_skb(cdev, skb, timestamp);
return 1;
}
@@ -674,6 +702,7 @@ static int m_can_handle_state_change(struct net_device *dev,
struct sk_buff *skb;
struct can_berr_counter bec;
unsigned int ecr;
+ u32 timestamp = 0;
switch (new_state) {
case CAN_STATE_ERROR_WARNING:
@@ -735,7 +764,11 @@ static int m_can_handle_state_change(struct net_device *dev,
stats->rx_packets++;
stats->rx_bytes += cf->len;
- netif_receive_skb(skb);
+
+ if (cdev->is_peripheral)
+ timestamp = m_can_get_timestamp(cdev);
+
+ m_can_receive_skb(cdev, skb, timestamp);
return 1;
}
@@ -800,6 +833,7 @@ static int m_can_handle_protocol_error(struct net_device *dev, u32 irqstatus)
struct m_can_classdev *cdev = netdev_priv(dev);
struct can_frame *cf;
struct sk_buff *skb;
+ u32 timestamp = 0;
/* propagate the error condition to the CAN stack */
skb = alloc_can_err_skb(dev, &cf);
@@ -821,7 +855,11 @@ static int m_can_handle_protocol_error(struct net_device *dev, u32 irqstatus)
netdev_dbg(dev, "allocation of skb failed\n");
return 0;
}
- netif_receive_skb(skb);
+
+ if (cdev->is_peripheral)
+ timestamp = m_can_get_timestamp(cdev);
+
+ m_can_receive_skb(cdev, skb, timestamp);
return 1;
}
@@ -922,6 +960,29 @@ static int m_can_poll(struct napi_struct *napi, int quota)
return work_done;
}
+/* Echo tx skb and update net stats. Peripherals use rx-offload for
+ * echo. timestamp is used for peripherals to ensure correct ordering
+ * by rx-offload, and is ignored for non-peripherals.
+*/
+static void m_can_tx_update_stats(struct m_can_classdev *cdev,
+ unsigned int msg_mark,
+ u32 timestamp)
+{
+ struct net_device *dev = cdev->net;
+ struct net_device_stats *stats = &dev->stats;
+
+ if (cdev->is_peripheral)
+ stats->tx_bytes +=
+ can_rx_offload_get_echo_skb(&cdev->offload,
+ msg_mark,
+ timestamp,
+ NULL);
+ else
+ stats->tx_bytes += can_get_echo_skb(dev, msg_mark, NULL);
+
+ stats->tx_packets++;
+}
+
static void m_can_echo_tx_event(struct net_device *dev)
{
u32 txe_count = 0;
@@ -931,7 +992,6 @@ static void m_can_echo_tx_event(struct net_device *dev)
unsigned int msg_mark;
struct m_can_classdev *cdev = netdev_priv(dev);
- struct net_device_stats *stats = &dev->stats;
/* read tx event fifo status */
m_can_txefs = m_can_read(cdev, M_CAN_TXEFS);
@@ -941,21 +1001,23 @@ static void m_can_echo_tx_event(struct net_device *dev)
/* Get and process all sent elements */
for (i = 0; i < txe_count; i++) {
+ u32 txe, timestamp = 0;
+
/* retrieve get index */
fgi = (m_can_read(cdev, M_CAN_TXEFS) & TXEFS_EFGI_MASK) >>
TXEFS_EFGI_SHIFT;
- /* get message marker */
- msg_mark = (m_can_txe_fifo_read(cdev, fgi, 4) &
- TX_EVENT_MM_MASK) >> TX_EVENT_MM_SHIFT;
+ /* get message marker, timestamp */
+ txe = m_can_txe_fifo_read(cdev, fgi, 4);
+ msg_mark = (txe & TX_EVENT_MM_MASK) >> TX_EVENT_MM_SHIFT;
+ timestamp = FIELD_GET(TX_EVENT_TXTS_MASK, txe);
/* ack txe element */
m_can_write(cdev, M_CAN_TXEFA, (TXEFA_EFAI_MASK &
(fgi << TXEFA_EFAI_SHIFT)));
/* update stats */
- stats->tx_bytes += can_get_echo_skb(dev, msg_mark, NULL);
- stats->tx_packets++;
+ m_can_tx_update_stats(cdev, msg_mark, timestamp);
}
}
@@ -963,7 +1025,6 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
{
struct net_device *dev = (struct net_device *)dev_id;
struct m_can_classdev *cdev = netdev_priv(dev);
- struct net_device_stats *stats = &dev->stats;
u32 ir;
if (pm_runtime_suspended(cdev->dev))
@@ -996,8 +1057,12 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
if (cdev->version == 30) {
if (ir & IR_TC) {
/* Transmission Complete Interrupt*/
- stats->tx_bytes += can_get_echo_skb(dev, 0, NULL);
- stats->tx_packets++;
+ u32 timestamp = 0;
+
+ if (cdev->is_peripheral)
+ timestamp = m_can_get_timestamp(cdev);
+ m_can_tx_update_stats(cdev, 0, timestamp);
+
can_led_event(dev, CAN_LED_EVENT_TX);
netif_wake_queue(dev);
}
@@ -1458,6 +1523,9 @@ static int m_can_close(struct net_device *dev)
cdev->tx_wq = NULL;
}
+ if (cdev->is_peripheral)
+ can_rx_offload_disable(&cdev->offload);
+
close_candev(dev);
can_led_event(dev, CAN_LED_EVENT_STOP);
@@ -1656,6 +1724,9 @@ static int m_can_open(struct net_device *dev)
goto exit_disable_clks;
}
+ if (cdev->is_peripheral)
+ can_rx_offload_enable(&cdev->offload);
+
/* register interrupt handler */
if (cdev->is_peripheral) {
cdev->tx_skb = NULL;
@@ -1697,6 +1768,8 @@ static int m_can_open(struct net_device *dev)
if (cdev->is_peripheral)
destroy_workqueue(cdev->tx_wq);
out_wq_fail:
+ if (cdev->is_peripheral)
+ can_rx_offload_disable(&cdev->offload);
close_candev(dev);
exit_disable_clks:
m_can_clk_stop(cdev);
@@ -1845,15 +1918,22 @@ int m_can_class_register(struct m_can_classdev *cdev)
return ret;
}
+ if (cdev->is_peripheral) {
+ ret = can_rx_offload_add_manual(cdev->net, &cdev->offload,
+ M_CAN_NAPI_WEIGHT);
+ if (ret)
+ goto clk_disable;
+ }
+
ret = m_can_dev_setup(cdev);
if (ret)
- goto clk_disable;
+ goto rx_offload_del;
ret = register_m_can_dev(cdev->net);
if (ret) {
dev_err(cdev->dev, "registering %s failed (err=%d)\n",
cdev->net->name, ret);
- goto clk_disable;
+ goto rx_offload_del;
}
devm_can_led_init(cdev->net);
@@ -1866,6 +1946,13 @@ int m_can_class_register(struct m_can_classdev *cdev)
/* Probe finished
* Stop clocks. They will be reactivated once the M_CAN device is opened
*/
+ m_can_clk_stop(cdev);
+
+ return 0;
+
+rx_offload_del:
+ if (cdev->is_peripheral)
+ can_rx_offload_del(&cdev->offload);
clk_disable:
m_can_clk_stop(cdev);
@@ -1875,6 +1962,8 @@ EXPORT_SYMBOL_GPL(m_can_class_register);
void m_can_class_unregister(struct m_can_classdev *cdev)
{
+ if (cdev->is_peripheral)
+ can_rx_offload_del(&cdev->offload);
unregister_candev(cdev->net);
}
EXPORT_SYMBOL_GPL(m_can_class_unregister);
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index 3fda84cef351..ace071c3e58c 100644
--- a/drivers/net/can/m_can/m_can.h
+++ b/drivers/net/can/m_can/m_can.h
@@ -8,6 +8,7 @@
#include <linux/can/core.h>
#include <linux/can/led.h>
+#include <linux/can/rx-offload.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
@@ -71,6 +72,7 @@ struct m_can_ops {
struct m_can_classdev {
struct can_priv can;
+ struct can_rx_offload offload;
struct napi_struct napi;
struct net_device *net;
struct device *dev;
--
2.30.2
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