imprecise external abort using the flexcan driver on i.MX6Q

Commit Message

Marc Kleine-Budde Sept. 27, 2013, 10:14 a.m. UTC

On 09/27/2013 12:04 PM, Lothar Waßmann wrote:

>> They layout of the flexcan varies in the different imx chips. I'm
>> comparing the datasheets at the moment. As Russell pointed out the area
>> staring at offset 0x80 is by the reception FIFO engine.
>>
> The layout is correct when the Rx FIFO is disabled!
> 
> removing 'FLEXCAN_MCR_FEN' from the MCR setting makes the driver work
> as expected (just without receive fifo).
> 
> For the use case with the FIFO enabled, the layout has to be changed
> obviously.

Can you just remove the loop completely? I think it's not needed. It
was in the original driver, when I picked it up.


Marc

Comments

Lothar Waßmann Sept. 27, 2013, 10:43 a.m. UTC | #1

Hi,

Marc Kleine-Budde writes:
> On 09/27/2013 12:04 PM, Lothar Waßmann wrote:
> 
> >> They layout of the flexcan varies in the different imx chips. I'm
> >> comparing the datasheets at the moment. As Russell pointed out the area
> >> staring at offset 0x80 is by the reception FIFO engine.
> >>
> > The layout is correct when the Rx FIFO is disabled!
> > 
> > removing 'FLEXCAN_MCR_FEN' from the MCR setting makes the driver work
> > as expected (just without receive fifo).
> > 
> > For the use case with the FIFO enabled, the layout has to be changed
> > obviously.
> 
> Can you just remove the loop completely? I think it's not needed. It
> was in the original driver, when I picked it up.
> 
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index e1ac75d..57ee3df 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -778,17 +778,6 @@ static int flexcan_chip_start(struct net_device *dev)
>         netdev_dbg(dev, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
>         flexcan_write(reg_ctrl, &regs->ctrl);
> 
> -       for (i = 0; i < ARRAY_SIZE(regs->cantxfg); i++) {
> -               flexcan_write(0, &regs->cantxfg[i].can_ctrl);
> -               flexcan_write(0, &regs->cantxfg[i].can_id);
> -               flexcan_write(0, &regs->cantxfg[i].data[0]);
> -               flexcan_write(0, &regs->cantxfg[i].data[1]);
> -
> -               /* put MB into rx queue */
> -               flexcan_write(FLEXCAN_MB_CNT_CODE(0x4),
> -                       &regs->cantxfg[i].can_ctrl);
> -       }
> -
>         /* acceptance mask/acceptance code (accept everything) */
>         flexcan_write(0x0, &regs->rxgmask);
>         flexcan_write(0x0, &regs->rx14mask);
> 
OK, done that. Driver works perfectly well now on i.MX6Q. I'll retest
on i.MX53 later to make sure it's still working there too.


Lothar Waßmann

Patch

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index e1ac75d..57ee3df 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -778,17 +778,6 @@  static int flexcan_chip_start(struct net_device *dev)
        netdev_dbg(dev, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
        flexcan_write(reg_ctrl, &regs->ctrl);

-       for (i = 0; i < ARRAY_SIZE(regs->cantxfg); i++) {
-               flexcan_write(0, &regs->cantxfg[i].can_ctrl);
-               flexcan_write(0, &regs->cantxfg[i].can_id);
-               flexcan_write(0, &regs->cantxfg[i].data[0]);
-               flexcan_write(0, &regs->cantxfg[i].data[1]);
-
-               /* put MB into rx queue */
-               flexcan_write(FLEXCAN_MB_CNT_CODE(0x4),
-                       &regs->cantxfg[i].can_ctrl);
-       }
-
        /* acceptance mask/acceptance code (accept everything) */
        flexcan_write(0x0, &regs->rxgmask);
        flexcan_write(0x0, &regs->rx14mask);