Unable to read firmware registers on crash?

[Michal Kazior]

On 1 February 2015 at 18:46, Ben Greear <greearb at candelatech.com> wrote:
> I am trying to debug a case where firmware occasionally crashes and
> the driver cannot read any crash dump to debug problem further.
>
> Any idea what might be the problem and how I might could read info
> from the firmware (or hack firmware to deliver the crash info in some
> other means...maybe though a previously reserved piece of memory on
> the host??)
>
> [147334.397148] ath10k: firmware crashed! (uuid
> ff405224-b2a4-493d-b619-19ad8152d190)
> [147334.404808] ath10k: hardware name qca988x hw2.0 version 0x4100016c
> [147334.411111] ath10k: firmware version: 10.1.467-ct-community-full-013
> [147334.429603] ath10k: failed to read diag value at 0x1300804: -16
> [147334.435647] ath10k: failed to read FW dump area address: -16

I see this rarely. Mostly when the device goes bonkers at which point
warm reset doesn't work anymore and I'm forced to either risk cold
reset causing platform lock up or re-inject the card in the express
card slot.

I haven't played with this so I don't know if DMA is still possible
(it might not). MMIO should be operational and there should be some
scratch registers chilling around... ;-)


Michał