bcma usage in isr context

bcma usage in isr context

[Arend van Spriel]

Hi Rafał,

I am doing some final testing on our brcmsmac driver, which I tinkered
to become a bcma device driver. During testing an issue popped up in the
ISR code.

Looking into the bcma read/write functions in host_pci.c I conclude that
bcma itself does not provide protection for concurrency. Am I correct in
that? How is this solved in b43?

Gr. AvS

Re: bcma usage in isr context

[Rafał Miłecki]

Hi,

Sorry for late reply, I was a little busy recently...

W dniu 1 grudnia 2011 14:09 użytkownik Arend van Spriel
<arend@broadcom.com> napisał:
> I am doing some final testing on our brcmsmac driver, which I tinkered
> to become a bcma device driver. During testing an issue popped up in the
> ISR code.

Do you mean interrupts code?


> Looking into the bcma read/write functions in host_pci.c I conclude that
> bcma itself does not provide protection for concurrency. Am I correct in
> that? How is this solved in b43?

I think I mean the fact that core driver can switch BCMA to
ChipCommon, while interrupt handler will try to access 80211 core?

You're right, we don't handle this properly. I'll try to send patch
today to make use of fixed windows. I've it here for some time
already, just didn't clean it enough.

-- 
Rafał

Re: bcma usage in isr context

[Arend van Spriel]

On 12/05/2011 12:30 PM, Rafał Miłecki wrote:
> Hi,
> 
> Sorry for late reply, I was a little busy recently...
> 
> W dniu 1 grudnia 2011 14:09 użytkownik Arend van Spriel
> <arend@broadcom.com> napisał:
>> I am doing some final testing on our brcmsmac driver, which I tinkered
>> to become a bcma device driver. During testing an issue popped up in the
>> ISR code.
> 
> Do you mean interrupts code?

Yep. ISR stands for 'interrupt service routine'.

>> Looking into the bcma read/write functions in host_pci.c I conclude that
>> bcma itself does not provide protection for concurrency. Am I correct in
>> that? How is this solved in b43?
> 
> I think I mean the fact that core driver can switch BCMA to
> ChipCommon, while interrupt handler will try to access 80211 core?

That is indeed what I mean.

> You're right, we don't handle this properly. I'll try to send patch
> today to make use of fixed windows. I've it here for some time
> already, just didn't clean it enough.
> 

Ok. For now I have a patch in the bcma read/write host_pci functions
that solves it, but fixed bar windows are preferable.

Gr. AvS

Re: bcma usage in isr context

[Rafał Miłecki]

W dniu 5 grudnia 2011 16:27 użytkownik Arend van Spriel
<arend@broadcom.com> napisał:
>> You're right, we don't handle this properly. I'll try to send patch
>> today to make use of fixed windows. I've it here for some time
>> already, just didn't clean it enough.
>>
>
> Ok. For now I have a patch in the bcma read/write host_pci functions
> that solves it, but fixed bar windows are preferable.

Have you tested my patch? Does it solver your issue? I can't wait to
see bcma patches for brcmsmac :)

-- 
Rafał

Re: bcma usage in isr context

[Arend van Spriel]

On 12/07/2011 01:52 PM, Rafał Miłecki wrote:
> W dniu 5 grudnia 2011 16:27 użytkownik Arend van Spriel
> <arend@broadcom.com> napisał:
>>> You're right, we don't handle this properly. I'll try to send patch
>>> today to make use of fixed windows. I've it here for some time
>>> already, just didn't clean it enough.
>>>
>>
>> Ok. For now I have a patch in the bcma read/write host_pci functions
>> that solves it, but fixed bar windows are preferable.
> 
> Have you tested my patch? Does it solver your issue? I can't wait to
> see bcma patches for brcmsmac :)
> 

Not yet. I had a patch in which each read/write used a
spin_lock_irqsave/spin_unlock_irqrestore. Did not cause to much latency.
I intend to rebase my changes using your patch later today.

Your patch only works if all cores fit in the window. This is the case
for the current pci-based broadcom chipsets so the patch is fine. I will
let you know the results. I also intend to do some suspend/resume
testing. I believe there was some issue mentioned on wireless mailing
list with bcma/b43.

Gr. AvS

Re: bcma usage in isr context

[Rafał Miłecki]

W dniu 7 grudnia 2011 15:01 użytkownik Arend van Spriel
<arend@broadcom.com> napisał:
> I also intend to do some suspend/resume
> testing. I believe there was some issue mentioned on wireless mailing
> list with bcma/b43.

That would be great. I don't have any notebook to use with Broadcom
card, that's why suspend&resume isn't implemented. I do all
development with my PC. In the notebook wireless card is integrated
with the motherboard.

-- 
Rafał

Re: bcma usage in isr context

[Arend van Spriel]

On 12/07/2011 04:06 PM, Rafał Miłecki wrote:
> W dniu 7 grudnia 2011 15:01 użytkownik Arend van Spriel
> <arend@broadcom.com> napisał:
>> I also intend to do some suspend/resume
>> testing. I believe there was some issue mentioned on wireless mailing
>> list with bcma/b43.
> 
> That would be great. I don't have any notebook to use with Broadcom
> card, that's why suspend&resume isn't implemented. I do all
> development with my PC. In the notebook wireless card is integrated
> with the motherboard.
> 

Hi Rafał,

Your patch works so I dropped my temp solution using spinlock. Regarding
suspend/resume it works for suspend-to-ram. The connection is not
reestablished, but that is probably because I have it not configured in
NetworkManager to automatically connect.

Gr. AvS