Does the reg_addr/reg_value reading work?

Does the reg_addr/reg_value reading work?

[Ben Greear]

I am not getting expected values when I try to read registers
through the ath10k reg_addr/reg_value API.

For instance, I tried reading a particular register 0x80e0
(as defined in the firmware), and I get a zero value.  With a different
API that I wrote to dump some specific registers over the WMI API,
I get the expected value.

# echo 0x80e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
# cat /debug/ieee80211/wiphy0/ath10k/reg_value
0x000080e0:0x00000000
# cat /debug/ieee80211/wiphy0/ath10k/fw_regs

   ath10k Target Register Dump
             =================

           MAC-FILTER-ADDR-L32 0xd7ffffff
...

Is there some trick I am missing?

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com


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Re: Does the reg_addr/reg_value reading work?

[Sebastian Gottschall]

Am 08.06.2015 um 18:11 schrieb Ben Greear:
> I am not getting expected values when I try to read registers
> through the ath10k reg_addr/reg_value API.
>
> For instance, I tried reading a particular register 0x80e0
> (as defined in the firmware), and I get a zero value.  With a different
> API that I wrote to dump some specific registers over the WMI API,
> I get the expected value.
>
> # echo 0x80e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
> # cat /debug/ieee80211/wiphy0/ath10k/reg_value
> 0x000080e0:0x00000000
> # cat /debug/ieee80211/wiphy0/ath10k/fw_regs
>
>     ath10k Target Register Dump
>               =================
>
>             MAC-FILTER-ADDR-L32 0xd7ffffff
> ...
>
> Is there some trick I am missing?
0x20000 offset makes the voodoo. you will find this offset within your 
firmware source too. take a look at the preconfigured register tables. 
these contain already the ack,slot etc. settings.
but with a special macro surrounding it which defines that offset

echo 0x2080e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr

>
> Thanks,
> Ben
>


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Re: Does the reg_addr/reg_value reading work?

[Ben Greear]

On 06/08/2015 09:46 AM, Sebastian Gottschall wrote:
> Am 08.06.2015 um 18:11 schrieb Ben Greear:
>> I am not getting expected values when I try to read registers
>> through the ath10k reg_addr/reg_value API.
>>
>> For instance, I tried reading a particular register 0x80e0
>> (as defined in the firmware), and I get a zero value.  With a different
>> API that I wrote to dump some specific registers over the WMI API,
>> I get the expected value.
>>
>> # echo 0x80e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>> # cat /debug/ieee80211/wiphy0/ath10k/reg_value
>> 0x000080e0:0x00000000
>> # cat /debug/ieee80211/wiphy0/ath10k/fw_regs
>>
>>     ath10k Target Register Dump
>>               =================
>>
>>             MAC-FILTER-ADDR-L32 0xd7ffffff
>> ...
>>
>> Is there some trick I am missing?
> 0x20000 offset makes the voodoo. you will find this offset within your firmware source too. take a look at the preconfigured register tables. these contain
> already the ack,slot etc. settings.
> but with a special macro surrounding it which defines that offset
> 
> echo 0x2080e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr

This crashes my kernel....I instrumented the place that crashed in ath10k/pci.h:

[  100.676013] ath10k-pci-read32: ar ffff88020279ae20  ar_pci ffff88020279df08  offset: 0x2080e0
[  100.676016]   ar_pci->mem: 0xffffc90019c80000
[  100.676031] BUG: unable to handle kernel paging request at ffffc90019e880e0
[  100.681752] IP: [<ffffffff81364ad4>] ioread32+0x9/0x2f

Have you tried this on a 10.1.467 firmware?

And, what kernel?  I'm trying 4.0.4+

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com


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Re: Does the reg_addr/reg_value reading work?

[Ben Greear]

On 06/08/2015 12:45 PM, Ben Greear wrote:
> On 06/08/2015 09:46 AM, Sebastian Gottschall wrote:
>> Am 08.06.2015 um 18:11 schrieb Ben Greear:
>>> I am not getting expected values when I try to read registers
>>> through the ath10k reg_addr/reg_value API.
>>>
>>> For instance, I tried reading a particular register 0x80e0
>>> (as defined in the firmware), and I get a zero value.  With a different
>>> API that I wrote to dump some specific registers over the WMI API,
>>> I get the expected value.
>>>
>>> # echo 0x80e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>>> # cat /debug/ieee80211/wiphy0/ath10k/reg_value
>>> 0x000080e0:0x00000000
>>> # cat /debug/ieee80211/wiphy0/ath10k/fw_regs
>>>
>>>     ath10k Target Register Dump
>>>               =================
>>>
>>>             MAC-FILTER-ADDR-L32 0xd7ffffff
>>> ...
>>>
>>> Is there some trick I am missing?
>> 0x20000 offset makes the voodoo. you will find this offset within your firmware source too. take a look at the preconfigured register tables. these contain
>> already the ack,slot etc. settings.
>> but with a special macro surrounding it which defines that offset
>>
>> echo 0x2080e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
> 
> This crashes my kernel....I instrumented the place that crashed in ath10k/pci.h:
> 
> [  100.676013] ath10k-pci-read32: ar ffff88020279ae20  ar_pci ffff88020279df08  offset: 0x2080e0
> [  100.676016]   ar_pci->mem: 0xffffc90019c80000
> [  100.676031] BUG: unable to handle kernel paging request at ffffc90019e880e0
> [  100.681752] IP: [<ffffffff81364ad4>] ioread32+0x9/0x2f
> 
> Have you tried this on a 10.1.467 firmware?
> 
> And, what kernel?  I'm trying 4.0.4+

I was using the wrong address value..it should be 0x280e0.  Maybe the driver should still keep us from
crashing the whole kernel (while holding locks!), but at least it works when I put in
the right value.

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com


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Re: Does the reg_addr/reg_value reading work?

[Sebastian Gottschall]

Am 08.06.2015 um 22:02 schrieb Ben Greear:
> On 06/08/2015 12:45 PM, Ben Greear wrote:
>> On 06/08/2015 09:46 AM, Sebastian Gottschall wrote:
>>> Am 08.06.2015 um 18:11 schrieb Ben Greear:
>>>> I am not getting expected values when I try to read registers
>>>> through the ath10k reg_addr/reg_value API.
>>>>
>>>> For instance, I tried reading a particular register 0x80e0
>>>> (as defined in the firmware), and I get a zero value.  With a different
>>>> API that I wrote to dump some specific registers over the WMI API,
>>>> I get the expected value.
>>>>
>>>> # echo 0x80e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>>>> # cat /debug/ieee80211/wiphy0/ath10k/reg_value
>>>> 0x000080e0:0x00000000
>>>> # cat /debug/ieee80211/wiphy0/ath10k/fw_regs
>>>>
>>>>      ath10k Target Register Dump
>>>>                =================
>>>>
>>>>              MAC-FILTER-ADDR-L32 0xd7ffffff
>>>> ...
>>>>
>>>> Is there some trick I am missing?
>>> 0x20000 offset makes the voodoo. you will find this offset within your firmware source too. take a look at the preconfigured register tables. these contain
>>> already the ack,slot etc. settings.
>>> but with a special macro surrounding it which defines that offset
>>>
>>> echo 0x2080e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>> This crashes my kernel....I instrumented the place that crashed in ath10k/pci.h:
>>
>> [  100.676013] ath10k-pci-read32: ar ffff88020279ae20  ar_pci ffff88020279df08  offset: 0x2080e0
>> [  100.676016]   ar_pci->mem: 0xffffc90019c80000
>> [  100.676031] BUG: unable to handle kernel paging request at ffffc90019e880e0
>> [  100.681752] IP: [<ffffffff81364ad4>] ioread32+0x9/0x2f
>>
>> Have you tried this on a 10.1.467 firmware?
>>
>> And, what kernel?  I'm trying 4.0.4+
> I was using the wrong address value..it should be 0x280e0.  Maybe the driver should still keep us from
> crashing the whole kernel (while holding locks!), but at least it works when I put in
> the right value.
now that you say it. i see it too. but playing direct register writes 
can always lead to problematic scenarios. its a debug register. from my 
oppinion, a debug register should allow
whatever is possible. even crashing something. its like using /dev/kmem
>
> Thanks,
> Ben
>
>


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Re: Does the reg_addr/reg_value reading work?

[Ben Greear]

On 06/08/2015 02:23 PM, Sebastian Gottschall wrote:
> Am 08.06.2015 um 22:02 schrieb Ben Greear:
>> On 06/08/2015 12:45 PM, Ben Greear wrote:
>>> On 06/08/2015 09:46 AM, Sebastian Gottschall wrote:
>>>> Am 08.06.2015 um 18:11 schrieb Ben Greear:
>>>>> I am not getting expected values when I try to read registers
>>>>> through the ath10k reg_addr/reg_value API.
>>>>>
>>>>> For instance, I tried reading a particular register 0x80e0
>>>>> (as defined in the firmware), and I get a zero value.  With a different
>>>>> API that I wrote to dump some specific registers over the WMI API,
>>>>> I get the expected value.
>>>>>
>>>>> # echo 0x80e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>>>>> # cat /debug/ieee80211/wiphy0/ath10k/reg_value
>>>>> 0x000080e0:0x00000000
>>>>> # cat /debug/ieee80211/wiphy0/ath10k/fw_regs
>>>>>
>>>>>      ath10k Target Register Dump
>>>>>                =================
>>>>>
>>>>>              MAC-FILTER-ADDR-L32 0xd7ffffff
>>>>> ...
>>>>>
>>>>> Is there some trick I am missing?
>>>> 0x20000 offset makes the voodoo. you will find this offset within your firmware source too. take a look at the preconfigured register tables. these contain
>>>> already the ack,slot etc. settings.
>>>> but with a special macro surrounding it which defines that offset
>>>>
>>>> echo 0x2080e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>>> This crashes my kernel....I instrumented the place that crashed in ath10k/pci.h:
>>>
>>> [  100.676013] ath10k-pci-read32: ar ffff88020279ae20  ar_pci ffff88020279df08  offset: 0x2080e0
>>> [  100.676016]   ar_pci->mem: 0xffffc90019c80000
>>> [  100.676031] BUG: unable to handle kernel paging request at ffffc90019e880e0
>>> [  100.681752] IP: [<ffffffff81364ad4>] ioread32+0x9/0x2f
>>>
>>> Have you tried this on a 10.1.467 firmware?
>>>
>>> And, what kernel?  I'm trying 4.0.4+
>> I was using the wrong address value..it should be 0x280e0.  Maybe the driver should still keep us from
>> crashing the whole kernel (while holding locks!), but at least it works when I put in
>> the right value.
> now that you say it. i see it too. but playing direct register writes can always lead to problematic scenarios. its a debug register. from my oppinion, a debug
> register should allow
> whatever is possible. even crashing something. its like using /dev/kmem

I am guessing the driver knows the pci address space that is available..it could probably
just limit any access outside those bounds since they can never work anyway.

Anyway, I'll let someone else deal with it if they want.

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com


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Re: Does the reg_addr/reg_value reading work?

[Michal Kazior]

On 8 June 2015 at 23:28, Ben Greear <greearb@candelatech.com> wrote:
> On 06/08/2015 02:23 PM, Sebastian Gottschall wrote:
>> Am 08.06.2015 um 22:02 schrieb Ben Greear:
>>> On 06/08/2015 12:45 PM, Ben Greear wrote:
>>>> On 06/08/2015 09:46 AM, Sebastian Gottschall wrote:
[...]
>>>>> echo 0x2080e0 > /debug/ieee80211/wiphy0/ath10k/reg_addr
>>>> This crashes my kernel....I instrumented the place that crashed in ath10k/pci.h:
>>>>
>>>> [  100.676013] ath10k-pci-read32: ar ffff88020279ae20  ar_pci ffff88020279df08  offset: 0x2080e0
>>>> [  100.676016]   ar_pci->mem: 0xffffc90019c80000
>>>> [  100.676031] BUG: unable to handle kernel paging request at ffffc90019e880e0
>>>> [  100.681752] IP: [<ffffffff81364ad4>] ioread32+0x9/0x2f
>>>>
>>>> Have you tried this on a 10.1.467 firmware?
>>>>
>>>> And, what kernel?  I'm trying 4.0.4+
>>> I was using the wrong address value..it should be 0x280e0.  Maybe the driver should still keep us from
>>> crashing the whole kernel (while holding locks!), but at least it works when I put in
>>> the right value.
>> now that you say it. i see it too. but playing direct register writes can always lead to problematic scenarios. its a debug register. from my oppinion, a debug
>> register should allow
>> whatever is possible. even crashing something. its like using /dev/kmem
>
> I am guessing the driver knows the pci address space that is available..it could probably
> just limit any access outside those bounds since they can never work anyway.
>
> Anyway, I'll let someone else deal with it if they want.

Yep. I've just sent a patch for review which introduces a sanity check
to prevent out of bounds MMIO access.


Michał

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