Hi Dong,

On 10/08/2012 09:59 AM, Dong Aisheng-B29396 wrote:

Hi Wolfgang,

quoted

On 10/07/2012 05:09 AM, Shawn Guo wrote:

quoted

On Fri, Sep 28, 2012 at 03:17:15PM +0200, Wolfgang Grandegger wrote:

quoted

Due to a bug in most Flexcan cores, the bus error interrupt needs to
be enabled. Otherwise we don't get any error warning or passive
interrupts. This is _not_ necessay for the i.MX28 and this patch
disables bus error interrupts if "berr-reporting" is not requested.
This avoids bus error flooding, which might harm, especially on
low-end systems.

To handle such quirks of the Flexcan cores, a hardware feature flag
has been introduced, also replacing the "hw_ver" variable. So far
nobody could tell what Flexcan core version is available on what
Freescale SOC, apart from the i.MX6Q and P1010, and which bugs or
features are present on the various "hw_rev".

CC: Hui Wang <redacted>
CC: Shawn Guo <redacted>
Signed-off-by: Wolfgang Grandegger <redacted>
---

Concerning the bug, I know that the i.MX35 does have it. Maybe other
Flexcan cores than on the i.MX28 does *not* have it either. If you
have a chance, please check on the P1010, i.MX6Q, i.MX51, i.MX53,
etc.

quoted

From what I can tell, i.MX35, i.MX51 and i.MX53 use the same version,

so they should all have the bug.  And for i.MX6Q, since it uses a
newer version even than i.MX28, I would believe it's affected by the bug.
But I'm copying Dong who should have better knowledge about this to
confirm.

Thank for clarification. I have a i.MX6Q board but without CAN adapter :(,
unfortunately. Otherwise I would try it out myself.

How did you verify this issue?

I provoke state changes, e.g. by sending a message without connection to
the bus. On the Mx28, the TWRN_INT/RWRN_INT/(BOFF_INT?) does trigger the
corresponding interrupt. This does not work properly on some other
cores, e.g. the Mx35. Therefore we enable ERR_INT for those cores to
realize state changes.

I just checked our ic guy of flexcan, it seems he also had no sense of this issue.

Below is some version info what I got:
Mx6s use FlexCAN3, with IP version 10.00.12.00
Mx53 use FlexCAN2 (with glitch filter), with IP version 03.00.00.00
Mx28 use FlexCAN2 (with glitch filter), with IP version 03.00.04.00
Mx35 use FlexCAN2 (without glitch filter) , with IP version 03.00.00.00
Mx25 use FlexCAN2 (without glitch filter), with IP version 03.00.00.00
I'm not sure if mx6q has such issue.

OK, we need to find that out experimentally.

Wolfgang.