GPIO IRQ on P1022

GPIO IRQ on P1022

[Felix Radensky]

Hi,

I'm running kernel 3.0 on a custom board based on Freescale P1022.
The interrupt line of on-board FPGA is connected to GPIO2_9. FPGA
IRQ is level, active low. The GPIOs are mapped like this:

GPIOs 160-191, /soc@ffe00000/gpio-controller@f200:

GPIOs 192-223, /soc@ffe00000/gpio-controller@f100:

GPIOs 224-255, /soc@ffe00000/gpio-controller@f000:

I've verified that pin mixing is done correctly, and the
FPGA IRQ line is indeed configured as GPIO.

I have the following code in my driver:

     #define FPGA_IRQ_GPIO 169

     err = gpio_request(FPGA_IRQ_GPIO, "FPGA IRQ");
     if (err) {
         printk(KERN_ERR "Failed to request FPGA IRQ GPIO, err=%d\n", 
err);
         goto out;
     }

     gpio_direction_input(FPGA_IRQ_GPIO);

     irq = gpio_to_irq(FPGA_IRQ_GPIO);
     if (irq < 0) {
         printk(KERN_ERR "Failed to map FPGA GPIO to IRQ\n");
         goto out;
     }

     err = request_irq(irq, gsat_interrupt,
               IRQF_TRIGGER_FALLING, DRVNAME, priv);

     Interrupt handler reads FPGA interrupt status register to clear 
interrupt
     and exits.

     What happens when I load my driver is single execution of 
interrupt handler
     followed by system freeze. Even if I call disable_irq() in 
interrupt handler the
     system still freezes.

     I've added some prints to mpc8xxx_gpio.c driver, here's what I get:

     mpc8xxx_gpio_to_irq: offset 9
     mpc8xxx_gpio_irq_map: virq 31
     irq: irq 9 on host /soc@ffe00000/gpio-controller@f200 mapped to 
virtual irq 31
     mpc8xxx_irq_set_type: virq 9 flow_type 2
     mpc8xxx_irq_unmask: irq 9
     mpc8xxx_gpio_irq_cascade: irq 47
     mpc8xxx_irq_mask: irq 9
     mpc8xxx_irq_ack: irq 9


What am I doing wrong ?

Thanks a lot.

Felix.

Re: GPIO IRQ on P1022

[Tabi Timur-B04825]

Felix Radensky wrote:
>
>      What happens when I load my driver is single execution of interrupt
> handler
>      followed by system freeze. Even if I call disable_irq() in interrupt
> handler the
>      system still freezes.

I don't know anything about the GPIO layer, but I think you're going to=20
need to debug this a little more.  Where exactly is the freeze?  Are you=20
sure the interrupt handler is being called only once?  Perhaps you're not=20
clearing the interrupt status and your handler is being called repeatedly?

--=20
Timur Tabi
Linux kernel developer at Freescale=

Re: GPIO IRQ on P1022

[Felix Radensky]

Hi Timur,

On 07/31/2011 04:59 PM, Tabi Timur-B04825 wrote:
> Felix Radensky wrote:
>>       What happens when I load my driver is single execution of interrupt
>> handler
>>       followed by system freeze. Even if I call disable_irq() in interrupt
>> handler the
>>       system still freezes.
> I don't know anything about the GPIO layer, but I think you're going to
> need to debug this a little more.  Where exactly is the freeze?  Are you
> sure the interrupt handler is being called only once?  Perhaps you're not
> clearing the interrupt status and your handler is being called repeatedly?
>

It was verified with oscilloscope that interrupt handler clears the
interrupt. The interrupt line goes from low to high and stays there.
I have prints in interrupt handler, they appear only once.

It's difficult to say where it freezes. I've tried magic sysrq on serial
console, but got nothing.


Felix.

Re: GPIO IRQ on P1022

[Felix Radensky]

Hi,

On 07/31/2011 04:59 PM, Tabi Timur-B04825 wrote:
> Felix Radensky wrote:
>>       What happens when I load my driver is single execution of interrupt
>> handler
>>       followed by system freeze. Even if I call disable_irq() in interrupt
>> handler the
>>       system still freezes.
> I don't know anything about the GPIO layer, but I think you're going to
> need to debug this a little more.  Where exactly is the freeze?  Are you
> sure the interrupt handler is being called only once?  Perhaps you're not
> clearing the interrupt status and your handler is being called repeatedly?
>

I'm trying to debug this problem, without much luck so far.
I've enabled hard and soft lock-up detection and various
locking debugging options in kernel configuration but nothing
shows up. I've also tried KGDB over serial line, and was able
to hit the breakpoint in mpc8xxx_gpio code, but was unable
to step through the code, gdb just freezes.

I'm getting the following after system locks up:

nfs: server 10.0.0.10 not responding, still trying
NETDEV WATCHDOG: eth0 (fsl-gianfar): transmit queue 0 timed out
------------[ cut here ]------------
WARNING: at net/sched/sch_generic.c:255
Modules linked in: gsat hal
NIP: c01a5e9c LR: c01a5e9c CTR: c01576bc
REGS: dfff1e90 TRAP: 0700   Not tainted  (3.0.0)
MSR: 00029000 <EE,ME,CE>  CR: 24044082  XER: 20000000
TASK = c02df3b8[0] 'swapper' THREAD: c02ee000
GPR00: c01a5e9c dfff1f40 c02df3b8 00000046 00003d04 ffffffff c01546e4 
00003d04
GPR08: c02e0000 c02ed710 00003d04 00000002 84044042 7dcac9f0 00000000 
00000000
GPR16: 1ff8c184 1ffa95e0 c0284070 c02f9dc0 c02fabec c02fa9ec c02fa7ec 
c02fa5ec
GPR24: 00200200 dfff1f68 c02e0000 dfff0000 c034c138 c02e0000 df011000 
00000000
NIP [c01a5e9c] dev_watchdog+0x298/0x2a8
LR [c01a5e9c] dev_watchdog+0x298/0x2a8
Call Trace:
[dfff1f40] [c01a5e9c] dev_watchdog+0x298/0x2a8 (unreliable)
[dfff1f60] [c00434e8] run_timer_softirq+0x1a4/0x1e0
[dfff1fb0] [c003cf20] __do_softirq+0x9c/0x114
[dfff1ff0] [c000c8a0] call_do_softirq+0x14/0x24
[c02efe90] [c00049ec] do_softirq+0x74/0x80
[c02efeb0] [c003d174] irq_exit+0x98/0x9c
[c02efec0] [c0009944] timer_interrupt+0xb4/0x118
[c02efed0] [c000e018] ret_from_except+0x0/0x18
--- Exception: 901 at cpu_idle+0x98/0xd8
     LR = cpu_idle+0x98/0xd8
[c02eff90] [c0008238] cpu_idle+0x50/0xd8 (unreliable)
[c02effb0] [c00022e4] rest_init+0x64/0x78
[c02effc0] [c02bb86c] start_kernel+0x244/0x2c0
[c02efff0] [c00003a0] skpinv+0x2b8/0x2f4
Instruction dump:
38000001 7c0903a6 4bfffe40 7fc3f378 4bfe7045 7fe6fb78 7c651b78 3c60c02a
7fc4f378 38639ac4 4cc63182 4be921dd <0fe00000> 38000001 981c0001 4bffff9c
---[ end trace 5d45e0fe33774f9c ]---


What else can be done to find the problem. ?

Thanks a lot in advance.

Felix.

Re: GPIO IRQ on P1022

[Wolfgang Grandegger]

On 07/31/2011 12:38 PM, Felix Radensky wrote:
> Hi,
> 
> I'm running kernel 3.0 on a custom board based on Freescale P1022.
> The interrupt line of on-board FPGA is connected to GPIO2_9. FPGA
> IRQ is level, active low. The GPIOs are mapped like this:
> 
> GPIOs 160-191, /soc@ffe00000/gpio-controller@f200:
> 
> GPIOs 192-223, /soc@ffe00000/gpio-controller@f100:
> 
> GPIOs 224-255, /soc@ffe00000/gpio-controller@f000:
> 
> I've verified that pin mixing is done correctly, and the
> FPGA IRQ line is indeed configured as GPIO.
> 
> I have the following code in my driver:
> 
>     #define FPGA_IRQ_GPIO 169
> 
>     err = gpio_request(FPGA_IRQ_GPIO, "FPGA IRQ");
>     if (err) {
>         printk(KERN_ERR "Failed to request FPGA IRQ GPIO, err=%d\n", err);
>         goto out;
>     }
> 
>     gpio_direction_input(FPGA_IRQ_GPIO);
> 
>     irq = gpio_to_irq(FPGA_IRQ_GPIO);
>     if (irq < 0) {
>         printk(KERN_ERR "Failed to map FPGA GPIO to IRQ\n");
>         goto out;
>     }
> 
>     err = request_irq(irq, gsat_interrupt,
>               IRQF_TRIGGER_FALLING, DRVNAME, priv);
> 
>     Interrupt handler reads FPGA interrupt status register to clear
> interrupt
>     and exits.
> 
>     What happens when I load my driver is single execution of interrupt
> handler
>     followed by system freeze. Even if I call disable_irq() in interrupt
> handler the
>     system still freezes.

Try disable_irq_nosync() instead.

Wolfgang.

Re: GPIO IRQ on P1022

[Felix Radensky]

Hi Wolfgang,

On 07/31/2011 06:19 PM, Wolfgang Grandegger wrote:
> On 07/31/2011 12:38 PM, Felix Radensky wrote:
>> Hi,
>>
>> I'm running kernel 3.0 on a custom board based on Freescale P1022.
>> The interrupt line of on-board FPGA is connected to GPIO2_9. FPGA
>> IRQ is level, active low. The GPIOs are mapped like this:
>>
>> GPIOs 160-191, /soc@ffe00000/gpio-controller@f200:
>>
>> GPIOs 192-223, /soc@ffe00000/gpio-controller@f100:
>>
>> GPIOs 224-255, /soc@ffe00000/gpio-controller@f000:
>>
>> I've verified that pin mixing is done correctly, and the
>> FPGA IRQ line is indeed configured as GPIO.
>>
>> I have the following code in my driver:
>>
>>      #define FPGA_IRQ_GPIO 169
>>
>>      err = gpio_request(FPGA_IRQ_GPIO, "FPGA IRQ");
>>      if (err) {
>>          printk(KERN_ERR "Failed to request FPGA IRQ GPIO, err=%d\n", err);
>>          goto out;
>>      }
>>
>>      gpio_direction_input(FPGA_IRQ_GPIO);
>>
>>      irq = gpio_to_irq(FPGA_IRQ_GPIO);
>>      if (irq<  0) {
>>          printk(KERN_ERR "Failed to map FPGA GPIO to IRQ\n");
>>          goto out;
>>      }
>>
>>      err = request_irq(irq, gsat_interrupt,
>>                IRQF_TRIGGER_FALLING, DRVNAME, priv);
>>
>>      Interrupt handler reads FPGA interrupt status register to clear
>> interrupt
>>      and exits.
>>
>>      What happens when I load my driver is single execution of interrupt
>> handler
>>      followed by system freeze. Even if I call disable_irq() in interrupt
>> handler the
>>      system still freezes.
> Try disable_irq_nosync() instead.
>
>

Thanks.  However this doesn't help either.

Felix.

Re: GPIO IRQ on P1022

[Wolfgang Grandegger]

Hi Felix,

On 07/31/2011 05:51 PM, Felix Radensky wrote:
> Hi Wolfgang,
> 
> On 07/31/2011 06:19 PM, Wolfgang Grandegger wrote:
>> On 07/31/2011 12:38 PM, Felix Radensky wrote:
>>> Hi,
>>>
>>> I'm running kernel 3.0 on a custom board based on Freescale P1022.
>>> The interrupt line of on-board FPGA is connected to GPIO2_9. FPGA
>>> IRQ is level, active low. The GPIOs are mapped like this:

Here you say that it's a level sensitive interrupt but ...

>>> GPIOs 160-191, /soc@ffe00000/gpio-controller@f200:
>>>
>>> GPIOs 192-223, /soc@ffe00000/gpio-controller@f100:
>>>
>>> GPIOs 224-255, /soc@ffe00000/gpio-controller@f000:
>>>
>>> I've verified that pin mixing is done correctly, and the
>>> FPGA IRQ line is indeed configured as GPIO.
>>>
>>> I have the following code in my driver:
>>>
>>>      #define FPGA_IRQ_GPIO 169
>>>
>>>      err = gpio_request(FPGA_IRQ_GPIO, "FPGA IRQ");
>>>      if (err) {
>>>          printk(KERN_ERR "Failed to request FPGA IRQ GPIO, err=%d\n",
>>> err);
>>>          goto out;
>>>      }
>>>
>>>      gpio_direction_input(FPGA_IRQ_GPIO);
>>>
>>>      irq = gpio_to_irq(FPGA_IRQ_GPIO);
>>>      if (irq<  0) {
>>>          printk(KERN_ERR "Failed to map FPGA GPIO to IRQ\n");
>>>          goto out;
>>>      }
>>>
>>>      err = request_irq(irq, gsat_interrupt,
>>>                IRQF_TRIGGER_FALLING, DRVNAME, priv);

.. you request here an edge triggered interrupt.

Wolfgang.

Re: GPIO IRQ on P1022

[Felix Radensky]

Hi Wolfgang,

On 07/31/2011 08:49 PM, Wolfgang Grandegger wrote:
> Hi Felix,
>
> On 07/31/2011 05:51 PM, Felix Radensky wrote:
>> Hi Wolfgang,
>>
>> On 07/31/2011 06:19 PM, Wolfgang Grandegger wrote:
>>> On 07/31/2011 12:38 PM, Felix Radensky wrote:
>>>> Hi,
>>>>
>>>> I'm running kernel 3.0 on a custom board based on Freescale P1022.
>>>> The interrupt line of on-board FPGA is connected to GPIO2_9. FPGA
>>>> IRQ is level, active low. The GPIOs are mapped like this:
> Here you say that it's a level sensitive interrupt but ...
>
>>>> GPIOs 160-191, /soc@ffe00000/gpio-controller@f200:
>>>>
>>>> GPIOs 192-223, /soc@ffe00000/gpio-controller@f100:
>>>>
>>>> GPIOs 224-255, /soc@ffe00000/gpio-controller@f000:
>>>>
>>>> I've verified that pin mixing is done correctly, and the
>>>> FPGA IRQ line is indeed configured as GPIO.
>>>>
>>>> I have the following code in my driver:
>>>>
>>>>       #define FPGA_IRQ_GPIO 169
>>>>
>>>>       err = gpio_request(FPGA_IRQ_GPIO, "FPGA IRQ");
>>>>       if (err) {
>>>>           printk(KERN_ERR "Failed to request FPGA IRQ GPIO, err=%d\n",
>>>> err);
>>>>           goto out;
>>>>       }
>>>>
>>>>       gpio_direction_input(FPGA_IRQ_GPIO);
>>>>
>>>>       irq = gpio_to_irq(FPGA_IRQ_GPIO);
>>>>       if (irq<   0) {
>>>>           printk(KERN_ERR "Failed to map FPGA GPIO to IRQ\n");
>>>>           goto out;
>>>>       }
>>>>
>>>>       err = request_irq(irq, gsat_interrupt,
>>>>                 IRQF_TRIGGER_FALLING, DRVNAME, priv);
> .. you request here an edge triggered interrupt.

Yes, that is is correct. mpc8xxx_gpio.c driver does not allow
level sensitive interrupts, so I had no choice but to specify
IRQF_TRIGGER_FALLING.

Felix.