Re: [Qemu-devel] Disabling IRQ error

[Xie Xianshan <xiexs@cn.fujitsu.com>]

Hi Max,
     Thanks for your patience and help.
     I`ve tried to do what you said, but the problem doesn`t go away.
And actually i cannot add a new register to the fpga device, because the 
fpga device i`m emulating already exists in the real world.
So i cannot change anything about hardware properties and linux driver 
for this device.

     By the way, how did you finally fix your problem?

Thanks,
  Simen

于 2013/09/11 17:29, Max Filippov 写道:
> On Wed, Sep 11, 2013 at 12:12 PM, Xie Xianshan<xiexs@cn.fujitsu.com>  wrote:
>>    I want to add a new device "fpga" for e500, and trigger an interrupt IRQ3
>> while the register BB_INTR_REG which belongs to device "fpga" is wrote by
>> the device driver of "fpga".
>>    For e500, IRQ3 is an external interrupt irq.
>>    According the debug log, the disabling error is encoutered during writing
>> BB_INTR_REG register.
>>    - write BB_INTR_REG register
>>        - qemu_irq_raise() is called.
>>        - after serval minutes,
>>          the error message about disabling irq is displayed.
>>    - continue the next execution without error(with poll?)
>
> So your device raises IRQ, but it doesn't lower it. Real devices
> usually don't do that, they either generate a short pulse on the
> IRQ line (in case of edge-triggered IRQ) or raise IRQ line on
> some event and then lower it on a command from its driver
> (level-triggered IRQ).
>
> You can do the following to make your device behave that way:
> - make your fpga device capable of lowering its IRQ, e.g. by adding
>    another register:
>
>> static void fpga_write(FPGAState *s, unsigned int offset, uint32_t value,
>> unsigned size) {
>>      switch(offset) {
>>      case BB_INTR_REG:
>>          qemu_irq_raise(s->irq);
>>          break;
>         case BB_INTC_REG:
>             qemu_irq_lower(s->irq);
>             break;
>>      }
>> }
>
> - provide an interrupt service routine in the linux driver for your fpga
>    device that would check whether the interrupt was caused by its
>    device, and if so lower the device's IRQ.
>
> Thanks.
> -- Max
>
>


-- 
Best Regards
Xie Xianshan
--------------------------------------------------
Xie Xianshan
Development Dept.I
Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
No. 6 Wenzhu Road, Nanjing, 210012, China
PHONE: +86+25-86630566-9555
FUJITSU INTERNAL: 7998-9555
MAIL: xiexs@cn.fujitsu.com
--------------------------------------------------
This communication is for use by the intended recipient(s) only and may
contain information that is privileged, confidential and exempt from
disclosure under applicable law. If you are not an intended recipient of
this communication, you are hereby notified that any dissemination,
distribution or copying hereof is strictly prohibited.  If you have
received this communication in error, please notify me by reply e-mail,
permanently delete this communication from your system, and destroy any
hard copies you may have printed