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Date: Mon, 09 Sep 2013 11:47:55 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Benedikt Spranger <b.spranger@...utronix.de>
CC: netdev@...r.kernel.org,
Alexander Frank <Alexander.Frank@...rspaecher.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Holger Dengler <dengler@...utronix.de>,
"linux-can@...r.kernel.org" <linux-can@...r.kernel.org>
Subject: Re: [PATCH 08/16] c_can: Add FlexCard CAN TX fifo support
On 09/09/2013 09:25 AM, Benedikt Spranger wrote:
> The FlexCard DCAN implementation contains a specialized TX fifo function.
> Add the TX support for this function.
This patch looks a bit fishy. Is this compatible with existing
c_can/d_can hardware. It looks like you "use" frame->dlc to transport
some information.
> Signed-off-by: Benedikt Spranger <b.spranger@...utronix.de>
> ---
> drivers/net/can/c_can/c_can.c | 77 ++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 65 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
> index 39e2bb0..4b94f2d 100644
> --- a/drivers/net/can/c_can/c_can.c
> +++ b/drivers/net/can/c_can/c_can.c
> @@ -41,6 +41,7 @@
> #include <linux/can/error.h>
> #include <linux/can/led.h>
>
> +#include <linux/flexcard.h>
> #include "c_can.h"
>
> /* Number of interface registers */
> @@ -566,24 +567,60 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
> u32 msg_obj_no;
> struct c_can_priv *priv = netdev_priv(dev);
> struct can_frame *frame = (struct can_frame *)skb->data;
> + int tx_fifo;
>
> if (can_dropped_invalid_skb(dev, skb))
> return NETDEV_TX_OK;
>
> - msg_obj_no = get_tx_next_msg_obj(priv);
> + tx_fifo = frame->can_dlc & FC_TXFIFO_FLAG;
Can you describe what you have encoded into to frame->can_dlc?
> + frame->can_dlc &= FC_TXFIFO_DLC_MASK;
>
> - /* prepare message object for transmission */
> - c_can_write_msg_object(dev, 0, frame, msg_obj_no);
> - can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
> + if (tx_fifo) {
> + u32 id, *data, ctrl;
>
> - /*
> - * we have to stop the queue in case of a wrap around or
> - * if the next TX message object is still in use
> - */
> - priv->tx_next++;
> - if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) ||
> - (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0)
> - netif_stop_queue(dev);
> + if (readl(priv->base + FC_TXFIFO_STAT) &
> + FC_TXFIFO_STAT_FULL) {
> + netif_stop_queue(dev);
> + return NETDEV_TX_BUSY;
> + }
> +
> + if (frame->can_id & CAN_EFF_FLAG) {
> + id = frame->can_id & CAN_EFF_MASK;
> + id |= FC_TXFIFO_MSGID_EXT;
> + } else {
> + id = frame->can_id & CAN_SFF_MASK;
> + /* StdID is left alligned */
> + id <<= FC_TXFIFO_MSGID_STDID_SHIFT;
> + }
> +
> + writel(id, priv->base + FC_TXFIFO_MSGID);
> + writel(frame->can_dlc, priv->base + FC_TXFIFO_MSGCTRL);
> +
> + if (frame->can_dlc) {
> + data = (u32 *) frame->data;
> + writel(data[0], priv->base + FC_TXFIFO_MSGDA);
> + writel(data[1], priv->base + FC_TXFIFO_MSGDB);
> + }
> +
> + ctrl = readl(priv->base + FC_TXFIFO_CTRL);
> + ctrl |= FC_TXFIFO_CTRL_REQ;
> + writel(ctrl, priv->base + FC_TXFIFO_CTRL);
> + kfree_skb(skb);
> + } else {
> + msg_obj_no = get_tx_next_msg_obj(priv);
> +
> + /* prepare message object for transmission */
> + c_can_write_msg_object(dev, 0, frame, msg_obj_no);
> + priv->tx_next++;
> +
> + can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
> + /* we have to stop the queue in case of a wrap around or
> + * if the next TX message object is still in use
> + */
> + if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv))
> + || ((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0))
> + netif_stop_queue(dev);
> + }
>
> return NETDEV_TX_OK;
> }
> @@ -683,6 +720,8 @@ static void c_can_configure_msg_objects(struct net_device *dev, int invalidate)
> IF_MASK_MDIR | IF_MASK_RES, 0,
> IF_MCONT_UMASK | IF_MCONT_EOB |
> IF_MCONT_RXIE | IF_MCONT_DLC_MAX);
> +
> + c_can_inval_msg_object(dev, 0, FC_TXFIFO_MO);
> }
>
> /*
> @@ -740,8 +779,13 @@ static int c_can_chip_config(struct net_device *dev)
> static int c_can_start(struct net_device *dev)
> {
> struct c_can_priv *priv = netdev_priv(dev);
> + u32 conf;
> int ret;
>
> + conf = readl(priv->base + FC_TXFIFO_CONF);
> + conf |= FC_TXFIFO_CONF_EN;
> + writel(conf, priv->base + FC_TXFIFO_CONF);
> +
> /* basic c_can configuration */
> ret = c_can_chip_config(dev);
> if (ret)
> @@ -762,6 +806,11 @@ out:
> static void c_can_stop(struct net_device *dev)
> {
> struct c_can_priv *priv = netdev_priv(dev);
> + u32 conf;
> +
> + conf = readl(priv->base + FC_TXFIFO_CONF);
> + conf &= ~FC_TXFIFO_CONF_EN;
> + writel(conf, priv->base + FC_TXFIFO_CONF);
>
> /* disable all interrupts */
> c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
> @@ -1350,6 +1399,8 @@ int register_c_can_dev(struct net_device *dev)
> struct c_can_priv *priv = netdev_priv(dev);
> int err;
>
> + writel(0, priv->base + FC_TXFIFO_CONF);
> +
> c_can_pm_runtime_enable(priv);
>
> dev->flags |= IFF_ECHO; /* we support local echo */
> @@ -1369,6 +1420,8 @@ void unregister_c_can_dev(struct net_device *dev)
> {
> struct c_can_priv *priv = netdev_priv(dev);
>
> + writel(0, priv->base + FC_TXFIFO_CONF);
> +
> unregister_candev(dev);
>
> c_can_pm_runtime_disable(priv);
>
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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