On 03/18/2014 06:19 PM, Thomas Gleixner wrote: > According to the documentation the CPU must wait for CONTROL_INIT to > be cleared before writing to the baudrate registers.
Thanks for the catch.
> Signed-off-by: Benedikt Spranger <b.spran...@linutronix.de>
> Signed-off-by: Thomas Gleixner <t...@linutronix.de>
>
> ---
> drivers/net/can/c_can/c_can.c | 26 +++++++++++++++++++++++---
> 1 file changed, 23 insertions(+), 3 deletions(-)
>
> Index: linux/drivers/net/can/c_can/c_can.c
> ===================================================================
> --- linux.orig/drivers/net/can/c_can/c_can.c
> +++ linux/drivers/net/can/c_can/c_can.c
> @@ -566,6 +566,21 @@ static netdev_tx_t c_can_start_xmit(stru
> return NETDEV_TX_OK;
> }
>
> +static int c_can_wait_for_ctrl_init(struct net_device *dev,
> + struct c_can_priv *priv, u32 init)
> +{
> + int retry = 0;
> +
> + while (init != (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_INIT)) {
> + udelay(10);
> + if (retry++ > 1000) {
> + netdev_err(dev, "CCTRL: set CONTROL_INIT failed\n");
> + return -EIO;
> + }
> + }
> + return 0;
> +}
> +
> static int c_can_set_bittiming(struct net_device *dev)
> {
> unsigned int reg_btr, reg_brpe, ctrl_save;
> @@ -573,6 +588,7 @@ static int c_can_set_bittiming(struct ne
> u32 ten_bit_brp;
> struct c_can_priv *priv = netdev_priv(dev);
> const struct can_bittiming *bt = &priv->can.bittiming;
> + int res;
>
> /* c_can provides a 6-bit brp and 4-bit brpe fields */
> ten_bit_brp = bt->brp - 1;
> @@ -590,13 +606,17 @@ static int c_can_set_bittiming(struct ne
> "setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe);
>
> ctrl_save = priv->read_reg(priv, C_CAN_CTRL_REG);
> - priv->write_reg(priv, C_CAN_CTRL_REG,
> - ctrl_save | CONTROL_CCE | CONTROL_INIT);
> + ctrl_save &= ~CONTROL_INIT;
> + priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_CCE | CONTROL_INIT);
> + res = c_can_wait_for_ctrl_init(dev, priv, CONTROL_INIT);
> + if (res)
> + return res;
> +
> priv->write_reg(priv, C_CAN_BTR_REG, reg_btr);
> priv->write_reg(priv, C_CAN_BRPEXT_REG, reg_brpe);
> priv->write_reg(priv, C_CAN_CTRL_REG, ctrl_save);
>
> - return 0;
> + return c_can_wait_for_ctrl_init(dev, priv, 0);
I'll post a patch that adds return value checking of all direct and
indirect users of c_can_set_bittiming().
> }
>
> /*
Thanks,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
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