This is a note to let you know that I've just added the patch titled
can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
can-mcp251xfd-fix-ring-configuration-when-switching-.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a4fce128c2c323f3e4345f3ab11404d3ebf43340
Author: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Date: Fri Jul 5 17:28:27 2024 +0200
can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode
[ Upstream commit 50ea5449c56310d2d31c28ba91a59232116d3c1e ]
If the ring (rx, tx) and/or coalescing parameters (rx-frames-irq,
tx-frames-irq) have been configured while the interface was in CAN-CC
mode, but the interface is brought up in CAN-FD mode, the ring
parameters might be too big.
Use the default CAN-FD values in this case.
Fixes: 9263c2e92be9 ("can: mcp251xfd: ring: add support for runtime configurable RX/TX ring parameters")
Link: https://lore.kernel.org/all/20240805-mcp251xfd-fix-ringconfig-v1-1-72086f0ca5ee@xxxxxxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c
index 9e8e82cdba46..61b0d6fa52dd 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c
@@ -97,7 +97,16 @@ void can_ram_get_layout(struct can_ram_layout *layout,
if (ring) {
u8 num_rx_coalesce = 0, num_tx_coalesce = 0;
- num_rx = can_ram_rounddown_pow_of_two(config, &config->rx, 0, ring->rx_pending);
+ /* If the ring parameters have been configured in
+ * CAN-CC mode, but and we are in CAN-FD mode now,
+ * they might be to big. Use the default CAN-FD values
+ * in this case.
+ */
+ num_rx = ring->rx_pending;
+ if (num_rx > layout->max_rx)
+ num_rx = layout->default_rx;
+
+ num_rx = can_ram_rounddown_pow_of_two(config, &config->rx, 0, num_rx);
/* The ethtool doc says:
* To disable coalescing, set usecs = 0 and max_frames = 1.
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
index 4cb79a4f2461..3a941a71c78f 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
@@ -468,11 +468,25 @@ int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv)
/* switching from CAN-2.0 to CAN-FD mode or vice versa */
if (fd_mode != test_bit(MCP251XFD_FLAGS_FD_MODE, priv->flags)) {
+ const struct ethtool_ringparam ring = {
+ .rx_pending = priv->rx_obj_num,
+ .tx_pending = priv->tx->obj_num,
+ };
+ const struct ethtool_coalesce ec = {
+ .rx_coalesce_usecs_irq = priv->rx_coalesce_usecs_irq,
+ .rx_max_coalesced_frames_irq = priv->rx_obj_num_coalesce_irq,
+ .tx_coalesce_usecs_irq = priv->tx_coalesce_usecs_irq,
+ .tx_max_coalesced_frames_irq = priv->tx_obj_num_coalesce_irq,
+ };
struct can_ram_layout layout;
- can_ram_get_layout(&layout, &mcp251xfd_ram_config, NULL, NULL, fd_mode);
- priv->rx_obj_num = layout.default_rx;
- tx_ring->obj_num = layout.default_tx;
+ can_ram_get_layout(&layout, &mcp251xfd_ram_config, &ring, &ec, fd_mode);
+
+ priv->rx_obj_num = layout.cur_rx;
+ priv->rx_obj_num_coalesce_irq = layout.rx_coalesce;
+
+ tx_ring->obj_num = layout.cur_tx;
+ priv->tx_obj_num_coalesce_irq = layout.tx_coalesce;
}
if (fd_mode) {
