Hallo Dan,
Am 05.03.19 um 16:52 schrieb Dan Murphy:
> Create a m_can platform framework that peripherial
> devices can register to and use common code and register sets.
> The peripherial devices may provide read/write and configuration
> support of the IP.
>
> Signed-off-by: Dan Murphy <dmur...@ti.com>
> ---
>
>
> v7 - Fixed remaining new checkpatch issues, removed CSR setting, fixed tx hard
> start function to return tx_busy, and renamed device callbacks -
> https://lore.kernel.org/patchwork/patch/1047220/
>
> v6 - Squashed platform patch to this patch for bissectablity, fixed coding
> style
> issues, updated Kconfig help, placed mcan reg offsets back into c file,
> renamed
> priv->skb to priv->tx_skb and cleared perp interrupts at ISR start -
> Patch 1 comments - https://lore.kernel.org/patchwork/patch/1042446/
> Patch 2 comments - https://lore.kernel.org/patchwork/patch/1042442/
>
> drivers/net/can/m_can/Kconfig | 13 +-
> drivers/net/can/m_can/Makefile | 1 +
> drivers/net/can/m_can/m_can.c | 700 +++++++++++++------------
> drivers/net/can/m_can/m_can.h | 110 ++++
> drivers/net/can/m_can/m_can_platform.c | 202 +++++++
> 5 files changed, 682 insertions(+), 344 deletions(-)
> create mode 100644 drivers/net/can/m_can/m_can.h
> create mode 100644 drivers/net/can/m_can/m_can_platform.c
>
> diff --git a/drivers/net/can/m_can/Kconfig b/drivers/net/can/m_can/Kconfig
> index 04f20dd39007..f7119fd72df4 100644
> --- a/drivers/net/can/m_can/Kconfig
> +++ b/drivers/net/can/m_can/Kconfig
> @@ -1,5 +1,14 @@
> config CAN_M_CAN
> + tristate "Bosch M_CAN support"
> + ---help---
> + Say Y here if you want support for Bosch M_CAN controller framework.
> + This is common support for devices that embed the Bosch M_CAN IP.
> +
> +config CAN_M_CAN_PLATFORM
> + tristate "Bosch M_CAN support for io-mapped devices"
> depends on HAS_IOMEM
> - tristate "Bosch M_CAN devices"
> + depends on CAN_M_CAN
> ---help---
> - Say Y here if you want to support for Bosch M_CAN controller.
> + Say Y here if you want support for IO Mapped Bosch M_CAN controller.
> + This support is for devices that have the Bosch M_CAN controller
> + IP embedded into the device and the IP is IO Mapped to the processor.
> diff --git a/drivers/net/can/m_can/Makefile b/drivers/net/can/m_can/Makefile
> index 8bbd7f24f5be..057bbcdb3c74 100644
> --- a/drivers/net/can/m_can/Makefile
> +++ b/drivers/net/can/m_can/Makefile
> @@ -3,3 +3,4 @@
> #
>
> obj-$(CONFIG_CAN_M_CAN) += m_can.o
> +obj-$(CONFIG_CAN_M_CAN_PLATFORM) += m_can_platform.o
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index 9b449400376b..a60278d94126 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
... snip...
> +static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
> + struct net_device *dev)
> +{
> + struct m_can_priv *priv = netdev_priv(dev);
> +
> + if (can_dropped_invalid_skb(dev, skb))
> + return NETDEV_TX_OK;
> +
> + if (priv->is_peripherial) {
> + if (priv->tx_skb) {
> + netdev_err(dev, "hard_xmit called while tx busy\n");
> + return NETDEV_TX_BUSY;
> + }
The problem with that approach is, that the upper layer will try to
resubmit the current "skb" but not the previous "tx_skb". And the
previous "tx_skb" has not been freed yet. I would just drop and free the
skb and return NETDEV_TX_OK in m_can_tx_handler() for peripheral devices
(like can_dropped_invalid_skb() does).
> +
> + priv->tx_skb = skb;
> + netif_stop_queue(priv->net);
> + queue_work(priv->tx_wq, &priv->tx_work);
> + } else {
> + priv->tx_skb = skb;
> + return m_can_tx_handler(priv);
> }
>
> return NETDEV_TX_OK;
> }
Wolfgang.
