Re: [PATCH 2/3] can: add support for Janz VMOD-ICAN3 IntelligentCAN module

From: Wolfgang Grandegger
Date: Mon Mar 22 2010 - 15:18:58 EST


Ira W. Snyder wrote:
> On Sat, Mar 20, 2010 at 08:55:16AM +0100, Wolfgang Grandegger wrote:
>> Ira W. Snyder wrote:
[snip]
>>> Does this seem right? It seems pretty good to me.
>> Yes, I'm just missing an error-passive message. What state does "ip -d
>> link show can0" report.
>>
>
> Ok, here is what I did:
>
> $ ip link set can0 up type can bitrate 1000000
> $ ip link set can1 up type can bitrate 1000000 berr-reporting on
> $ ip -d -s link
> 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
> link/can
> can state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0
> bitrate 1000000 sample-point 0.750
> tq 125 prop-seg 2 phase-seg1 3 phase-seg2 2 sjw 1
> janz-ican3: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
> clock 8000000
> re-started bus-errors arbit-lost error-warn error-pass bus-off
> 0 0 0 0 0 0
> RX: bytes packets errors dropped overrun mcast
> 0 0 0 0 0 0
> TX: bytes packets errors dropped carrier collsns
> 0 0 0 0 0 0
> 6: can1: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
> link/can
> can <BERR-REPORTING> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0
> bitrate 1000000 sample-point 0.750
> tq 125 prop-seg 2 phase-seg1 3 phase-seg2 2 sjw 1
> janz-ican3: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
> clock 8000000
> re-started bus-errors arbit-lost error-warn error-pass bus-off
> 0 0 0 0 0 0
> RX: bytes packets errors dropped overrun mcast
> 0 0 0 0 0 0
> TX: bytes packets errors dropped carrier collsns
> 0 0 0 0 0 0
>
> Now, in seperate windows, I ran cansequence and candump. I stopped
> cansequence when it could not send any more packets (due to the cable
> being unplugged).
>
> $ cansequence -v -e -p can0
> $ cansequence -v -e -p can1
> $ candump any,0~0,#FFFFFFFF
> can0 20000004 [8] 00 08 00 00 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000004 [8] 00 08 00 00 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
> can1 20000088 [8] 00 00 80 19 00 00 00 00 ERRORFRAME
>
> This last message is repeated lots more times. That's the flooding we're
> avoiding with berr-reporting off.
>
> I see two types of messages here:
> 1) bus error (only on can1)
> 2) controller problems -- tx warning limit reached (both)
>
> Am I missing some message? My error frame generation was mostly copied
> from the sja1000 driver.

It seem that you are not getting the error passive interrupt even...

> $ ip -d -s link
> 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
> link/can
> can state ERROR-WARNING (berr-counter tx 128 rx 0) restart-ms 0

if the hardware already reports >= 128 errors --^.

> bitrate 1000000 sample-point 0.750
> tq 125 prop-seg 2 phase-seg1 3 phase-seg2 2 sjw 1
> janz-ican3: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
> clock 8000000
> re-started bus-errors arbit-lost error-warn error-pass bus-off
> 0 0 0 1 0 0
> RX: bytes packets errors dropped overrun mcast
> 16 0 2 0 0 0
> TX: bytes packets errors dropped carrier collsns
> 513 513 0 0 0 0
> 6: can1: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
> link/can
> can <BERR-REPORTING> state ERROR-WARNING (berr-counter tx 128 rx 0) restart-ms 0
> bitrate 1000000 sample-point 0.750
> tq 125 prop-seg 2 phase-seg1 3 phase-seg2 2 sjw 1
> janz-ican3: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
> clock 8000000
> re-started bus-errors arbit-lost error-warn error-pass bus-off
> 0 126 0 1 0 0

But that's mabe because you stopped the test too early (just 126 bus errors).

> RX: bytes packets errors dropped overrun mcast
> 1024 0 254 0 0 0
> TX: bytes packets errors dropped carrier collsns
> 513 513 0 0 0 0

When I send out messages without cable connected I get:

-bash-3.2# ./ip -d -s link show can0
2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
link/can
can <BERR-REPORTING> state ERROR-PASSIVE (berr-counter tx 128 rx 0) restart-ms 0
bitrate 500000 sample-point 0.875
tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1
sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
clock 8000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 54101 0 1 1 0
RX: bytes packets errors dropped overrun mcast
432808 54101 54101 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0

The following output is without BERR-REPORTING:

-bash-3.2# ./candump -t d any,0:0,#FFFFFFFF
(0.000000) can0 20000004 [8] 00 08 00 00 00 00 60 00 ERRORFRAME
(0.000474) can0 20000004 [8] 00 20 00 00 00 00 80 00 ERRORFRAME
^ ^
TX RX error counter

The patch I mentioned also copies the rx and tx error counter values to
the data field 6 and 7.

Wolfgang.
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