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can: c_can: don't cache TX messages for C_CAN cores

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As Jacob noticed, the optimization introduced in 387da6bc7a ("can:
c_can: cache frames to operate as a true FIFO") doesn't properly work
on C_CAN, but on D_CAN IP cores. The exact reasons are still unknown.

For now disable caching if CAN frames in the TX path for C_CAN cores.

Fixes: 387da6bc7a ("can: c_can: cache frames to operate as a true FIFO")
Link: https://lore.kernel.org/all/20220928083354.1062321-1-mkl@pengutronix.de
Link: https://lore.kernel.org/all/15a8084b-9617-2da1-6704-d7e39d60643b@gmail.com
Reported-by: Jacob Kroon <jacob.kroon@gmail.com>
Tested-by: Jacob Kroon <jacob.kroon@gmail.com>
Cc: stable@vger.kernel.org # v5.15
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Marc Kleine-Budde 2022-09-23 13:42:23 +02:00
parent 44d70bb561
commit 81d192c2ce
2 changed files with 20 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/net/can/c_can/c_can.h
View File

@ -235,9 +235,22 @@ static inline u8 c_can_get_tx_tail(const struct c_can_tx_ring *ring)
return ring->tail & (ring->obj_num - 1);
}
static inline u8 c_can_get_tx_free(const struct c_can_tx_ring *ring)
static inline u8 c_can_get_tx_free(const struct c_can_priv *priv,
const struct c_can_tx_ring *ring)
{
return ring->obj_num - (ring->head - ring->tail);
u8 head = c_can_get_tx_head(ring);
u8 tail = c_can_get_tx_tail(ring);
if (priv->type == BOSCH_D_CAN)
return ring->obj_num - (ring->head - ring->tail);
/* This is not a FIFO. C/D_CAN sends out the buffers
* prioritized. The lowest buffer number wins.
*/
if (head < tail)
return 0;
return ring->obj_num - head;
}
#endif /* C_CAN_H */

11
drivers/net/can/c_can/c_can_main.c
View File

@ -429,7 +429,7 @@ static void c_can_setup_receive_object(struct net_device *dev, int iface,
static bool c_can_tx_busy(const struct c_can_priv *priv,
const struct c_can_tx_ring *tx_ring)
{
if (c_can_get_tx_free(tx_ring) > 0)
if (c_can_get_tx_free(priv, tx_ring) > 0)
return false;
netif_stop_queue(priv->dev);
@ -437,7 +437,7 @@ static bool c_can_tx_busy(const struct c_can_priv *priv,
/* Memory barrier before checking tx_free (head and tail) */
smp_mb();
if (c_can_get_tx_free(tx_ring) == 0) {
if (c_can_get_tx_free(priv, tx_ring) == 0) {
netdev_dbg(priv->dev,
"Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n",
tx_ring->head, tx_ring->tail,
@ -465,7 +465,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
idx = c_can_get_tx_head(tx_ring);
tx_ring->head++;
if (c_can_get_tx_free(tx_ring) == 0)
if (c_can_get_tx_free(priv, tx_ring) == 0)
netif_stop_queue(dev);
if (idx < c_can_get_tx_tail(tx_ring))
@ -748,7 +748,7 @@ static void c_can_do_tx(struct net_device *dev)
return;
tx_ring->tail += pkts;
if (c_can_get_tx_free(tx_ring)) {
if (c_can_get_tx_free(priv, tx_ring)) {
/* Make sure that anybody stopping the queue after
* this sees the new tx_ring->tail.
*/
@ -760,8 +760,7 @@ static void c_can_do_tx(struct net_device *dev)
stats->tx_packets += pkts;
tail = c_can_get_tx_tail(tx_ring);
if (tail == 0) {
if (priv->type == BOSCH_D_CAN && tail == 0) {
u8 head = c_can_get_tx_head(tx_ring);
/* Start transmission for all cached messages */