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Date: Mon, 22 Mar 2010 21:28:25 +0100
From: Wolfgang Grandegger <wg@...ndegger.com>
To: "Ira W. Snyder" <iws@...o.caltech.edu>
CC: socketcan-core@...ts.berlios.de, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, sameo@...ux.intel.com
Subject: Re: [PATCH 2/3] can: add support for Janz VMOD-ICAN3 Intelligent
CAN module
Ira W. Snyder wrote:
> On Mon, Mar 22, 2010 at 08:17:10PM +0100, Wolfgang Grandegger wrote:
>> 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 --^.
>>
>
> Re-reading the documentation, it appears that the firmware uses the
> error interrupt for two different indications. In the SJA1000 driver,
> they map to IRQ_EI and IRQ_EPI.
>
> The documentation says that you can tell when you get an error-passive
> only by checking the rxerr + txerr registers in the message. You'll note
> I omitted the IRQ_EPI-equivalent code from my driver when I copied the
> sja1000.c implementation.
>
> I've added an if-statement in the CEVTIND_EI path, which now looks like
> this. It handles both cases now.
>
> /* error warning interrupt */
> if (isrc == CEVTIND_EI) {
> u8 rxerr = msg->data[4];
> u8 txerr = msg->data[5];
>
> dev_dbg(mod->dev, "error warning interrupt\n");
> if (status & SR_BS) {
> state = CAN_STATE_BUS_OFF;
> cf->can_id |= CAN_ERR_BUSOFF;
> can_bus_off(dev);
> } else if (status & SR_ES) {
> if (rxerr >= 127 || txerr >= 127)
> state = CAN_STATE_ERROR_PASSIVE;
> else
> state = CAN_STATE_ERROR_WARNING;
> } else {
> state = CAN_STATE_ERROR_ACTIVE;
> }
> }
>
> The only change is in the "else if (status & SR_ES)" path. I had to add
> the if-statement that checks the rxerr and txerr registers. Does that
> seem ok? I got the 127 values from this webpage (provided to me on this
> mailing list).
It should be >= 128.
> http://www.softing.com/home/en/industrial-automation/products/can-bus/more-can-bus/error-handling/error-states.php?navanchor=3010510
>
>>> 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).
>>
>
> This is the best I could do. Without the cable connected, that's where
> the controller stops sending messages (cansequence just hangs waiting
> for buffer space to become available).
>
>>> 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
>
> With my newest changes, I get:
>
> 8: can1: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
> link/can
> can state ERROR-PASSIVE (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 0 0 3 3 0
> RX: bytes packets errors dropped overrun mcast
> 236045 235949 12 0 0 0
> TX: bytes packets errors dropped carrier collsns
> 235938 235938 0 0 0 0
>
> can1 20000004 [8] 00 08 00 00 00 00 60 00 ERRORFRAME
> can1 20000004 [8] 00 20 00 00 00 00 80 00 ERRORFRAME
>
> So it looks like both drivers agree (finally!). :)
>
> With berr-reporting on, I get the same flood of bus-error messages, with
> these two messages as well.
Looks good now.
>> The patch I mentioned also copies the rx and tx error counter values to
>> the data field 6 and 7.
>>
>
> I missed this. It has been added. Thanks for pointing it out.
You could even add the tx/rx values for each error message (for both,
state changes and bus-errors).
> I haven't heard back from Samuel Ortiz yet about the changes for the mfd
> layer. Would you like me to send out my latest CAN driver changes, or
> should I just wait until I hear back?
As you need patch 1/3 anyway, just wait some more time. From my point of
view the next version of the patch will be OK.
Wolfgang.
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