[PATCH v4 11/12] can: m_can: Implement BQL

From: Markus Schneider-Pargmann
Date: Wed Jun 21 2023 - 05:25:52 EST


Implement byte queue limiting in preparation for the use of xmit_more().

Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
---
drivers/net/can/m_can/m_can.c | 49 +++++++++++++++++++++++++----------
1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 38bdab9b5cd6..62e275c87c29 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -468,6 +468,8 @@ static void m_can_clean(struct net_device *net)
for (int i = 0; i != cdev->can.echo_skb_max; ++i)
can_free_echo_skb(cdev->net, i, NULL);

+ netdev_reset_queue(cdev->net);
+
spin_lock_irqsave(&cdev->tx_handling_spinlock, irqflags);
cdev->tx_fifo_in_flight = 0;
spin_unlock_irqrestore(&cdev->tx_handling_spinlock, irqflags);
@@ -1022,29 +1024,34 @@ static int m_can_poll(struct napi_struct *napi, int quota)
* 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)
+static unsigned int 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;
+ unsigned int frame_len;

if (cdev->is_peripheral)
stats->tx_bytes +=
can_rx_offload_get_echo_skb(&cdev->offload,
msg_mark,
timestamp,
- NULL);
+ &frame_len);
else
- stats->tx_bytes += can_get_echo_skb(dev, msg_mark, NULL);
+ stats->tx_bytes += can_get_echo_skb(dev, msg_mark, &frame_len);

stats->tx_packets++;
+
+ return frame_len;
}

-static void m_can_finish_tx(struct m_can_classdev *cdev, int transmitted)
+static void m_can_finish_tx(struct m_can_classdev *cdev, int transmitted,
+ unsigned int transmitted_frame_len)
{
unsigned long irqflags;

+ netdev_completed_queue(cdev->net, transmitted, transmitted_frame_len);
+
spin_lock_irqsave(&cdev->tx_handling_spinlock, irqflags);
if (cdev->tx_fifo_in_flight >= cdev->tx_fifo_size && transmitted > 0)
netif_wake_queue(cdev->net);
@@ -1083,6 +1090,7 @@ static int m_can_echo_tx_event(struct net_device *dev)
int err = 0;
unsigned int msg_mark;
int processed = 0;
+ unsigned int processed_frame_len = 0;

struct m_can_classdev *cdev = netdev_priv(dev);

@@ -1111,7 +1119,9 @@ static int m_can_echo_tx_event(struct net_device *dev)
fgi = (++fgi >= cdev->mcfg[MRAM_TXE].num ? 0 : fgi);

/* update stats */
- m_can_tx_update_stats(cdev, msg_mark, timestamp);
+ processed_frame_len += m_can_tx_update_stats(cdev, msg_mark,
+ timestamp);
+
++processed;
}

@@ -1119,7 +1129,7 @@ static int m_can_echo_tx_event(struct net_device *dev)
m_can_write(cdev, M_CAN_TXEFA, FIELD_PREP(TXEFA_EFAI_MASK,
ack_fgi));

- m_can_finish_tx(cdev, processed);
+ m_can_finish_tx(cdev, processed, processed_frame_len);

return err;
}
@@ -1194,11 +1204,12 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
if (ir & IR_TC) {
/* Transmission Complete Interrupt*/
u32 timestamp = 0;
+ unsigned int frame_len;

if (cdev->is_peripheral)
timestamp = m_can_get_timestamp(cdev);
- m_can_tx_update_stats(cdev, 0, timestamp);
- m_can_finish_tx(cdev, 1);
+ frame_len = m_can_tx_update_stats(cdev, 0, timestamp);
+ m_can_finish_tx(cdev, 1, frame_len);
}
} else {
if (ir & (IR_TEFN | IR_TEFW)) {
@@ -1715,6 +1726,7 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
u32 cccr, fdflags;
int err;
u32 putidx;
+ unsigned int frame_len = can_skb_get_frame_len(skb);

/* Generate ID field for TX buffer Element */
/* Common to all supported M_CAN versions */
@@ -1760,7 +1772,7 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
}
m_can_write(cdev, M_CAN_TXBTIE, 0x1);

- can_put_echo_skb(skb, dev, 0, 0);
+ can_put_echo_skb(skb, dev, 0, frame_len);

m_can_write(cdev, M_CAN_TXBAR, 0x1);
/* End of xmit function for version 3.0.x */
@@ -1798,7 +1810,7 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
/* Push loopback echo.
* Will be looped back on TX interrupt based on message marker
*/
- can_put_echo_skb(skb, dev, putidx, 0);
+ can_put_echo_skb(skb, dev, putidx, frame_len);

/* Enable TX FIFO element to start transfer */
m_can_write(cdev, M_CAN_TXBAR, (1 << putidx));
@@ -1869,14 +1881,23 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct m_can_classdev *cdev = netdev_priv(dev);
+ netdev_tx_t ret;
+ unsigned int frame_len;

if (can_dev_dropped_skb(dev, skb))
return NETDEV_TX_OK;

+ frame_len = can_skb_get_frame_len(skb);
+
if (cdev->is_peripheral)
- return m_can_start_peripheral_xmit(cdev, skb);
+ ret = m_can_start_peripheral_xmit(cdev, skb);
else
- return m_can_start_fast_xmit(cdev, skb);
+ ret = m_can_start_fast_xmit(cdev, skb);
+
+ if (ret == NETDEV_TX_OK)
+ netdev_sent_queue(dev, frame_len);
+
+ return ret;
}

static int m_can_open(struct net_device *dev)
--
2.40.1