allwinner/i2c interrupt storm detected

[Daniel Braniss]

> On 4 Jul 2020, at 13:29, Manuel Stühn <freebsdnewbie at freenet.de> wrote:
> 
> On Tue, 30 Jun 2020 16:01:41 +0300
> Daniel Braniss <danny at cs.huji.ac.il <mailto:danny at cs.huji.ac.il>> wrote:
> 
>> Hi,
>> 
>> after a long time I decided to try and upgrade to stable 12.1 r362793 since I saw some changes where done 
>> with respect to the DTS and twsi.c, 
>> 
>> if nothing is connected to the i2c, i2c -s just hangs,
>> 
>> if something is connected this is what i get on the console after typing ?i2c -s?
>> 
>> 
>> Hardware may not support START/STOP scanning; trinterrupt storm detected on "gic0,s6:"; throttling interrupt source
>> ying less-reliable read method.
>> interrupt storm detected on "gic0,s6:"; throttling interrupt source
>> interrupt storm detected on "gic0,s6:"; throttling interrupt source
>> ?
>> 
>> and
>> neo-04> vmstat -i
>> interrupt                                             total       rate
>> gic0,p13:-ic_timer0                                   16052        164
>> gic0,s0: uart2                                          318          3
>> gic0,s6: iichb0                                       13034        133
>> gic0,s60: aw_mmc0                                      1293         13
>> gic0,s82: awg0                                          334          3
>> gic0,s120: pmu0                                       49725        509
>> cpu0:rendezvous                                          18          0
>> cpu1:rendezvous                                          50          1
>> cpu2:rendezvous                                          51          1
>> cpu3:rendezvous                                          40          0
>> cpu0:preempt                                           2691         28
>> cpu1:preempt                                           3165         32
>> cpu2:preempt                                           2778         28
>> cpu3:preempt                                           2986         31
>> cpu0:hardclock                                           15          0
>> Total                                                 92550        946
>> 
>> 
>> the hardware is an NanoPi Neo
>> ---<<BOOT>>---
>> KDB: debugger backends: ddb
>> KDB: current backend: ddb
>> Copyright (c) 1992-2020 The FreeBSD Project.
>> Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
>>       The Regents of the University of California. All rights reserved.
>> FreeBSD is a registered trademark of The FreeBSD Foundation.
>> FreeBSD 12.1-STABLE #0 r362793M: Tue Jun 30 11:39:11 IDT 2020
>>   danny at nrnd:/home/obj/nrnd/arm/neo/vol/rnd/stable/12/arm.armv7/sys/AWGEN arm
>> FreeBSD clang version 10.0.0 (git at github.com <mailto:git at github.com>:llvm/llvm-project.git llvmorg-10.0.0-0-gd32170dbd5b)
>> VT: init without driver.
>> No PSCI/SMCCC call function found
>> CPU: ARM Cortex-A7 r0p5 (ECO: 0x00000000)
>> ?
>> 
> 
> I do not have a IRQ-Storm on my NanoPI NEO2, but a "i2s -s" does never return. Commit v356609 broke i2c-support on my hardware (reverting this single commit fixed it, bugreport filed: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247576 <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247576>).
> 
> Perhaps it is worth a try for you also to revert this commit and test again...
> 

before the latest changes it works fine, and if you add my patch to it, i2s -s will not hang:

> -- twsi.c	(revision 346538)
> +++ twsi.c	(working copy)
> @@ -458,8 +458,15 @@
> 		if (sc->msg->len == 1)
> 			sc->control_val &= ~TWSI_CONTROL_ACK;
> 		TWSI_WRITE(sc, sc->reg_control, sc->control_val | TWSI_CONTROL_START);
> -		while (sc->error == 0 && sc->transfer != 0) {
> -			pause_sbt("twsi", SBT_1MS * 30, SBT_1MS, 0);
> +		{
> +			 int count = 10;
> +			 while (sc->error == 0 && sc->transfer != 0) {
> +				  pause_sbt("twsi", SBT_1MS * 30, SBT_1MS, 0);
> +				  if(count-- == 0) {
> +					   sc->error = EDEADLK;
> +					   break;
> +				  }
> +			 }
> 		}
> 
> 		debugf(dev, "Done with msg[%d]\n", i);


cheers,
	danny

> 
> BR
> Manuel