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

From: Ira W. Snyder
Date: Mon Mar 22 2010 - 16:10:47 EST

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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).

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.

>
> 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.

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?

Ira
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Next message: Olimpiu Pascariu: "Re: [PATCH 5/5] Staging: cx25821: fix coding style issues incx25821-medusa-video.c"
Previous message: Liam Girdwood: "[GIT PULL] regulator fixes for 2.6.34-rc3"
In reply to: Ira W. Snyder: "Re: [PATCH 2/3] can: add support for Janz VMOD-ICAN3 IntelligentCAN module"
Next in thread: Wolfgang Grandegger: "Re: [PATCH 2/3] can: add support for Janz VMOD-ICAN3 IntelligentCAN module"
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