On 06/29/2016 03:08 AM, Stephen Warren wrote:

On 06/28/2016 03:15 AM, Joseph Lo wrote:

quoted

On 06/27/2016 11:55 PM, Stephen Warren wrote:

quoted

On 06/27/2016 03:02 AM, Joseph Lo wrote:

snip.

quoted

Currently the usage of HSP HW in the downstream kernel is something like
the model below.

remote_processor_A-\
remote_processor_B--->hsp at 1000 (doorbell func) <-> host CPU
remote_processor_C-/

remote_processor_D -> hsp at 2000 (shared mailbox) <-> CPU

remote_processor_E -> hsp at 3000 (shared mailbox) <-> CPU

I am thinking if we can just add the appropriate compatible strings for
it to replace "nvidia,tegra186-hsp". e.g. "nvidia,tegra186-hsp-doorbell"
and "nvidia,tegra186-hsp-sharedmailbox". So the driver can probe and
initialize correctly depend on the compatible property. How do you think
about it? Is this the same as the (b) you mentioned above?

Yes, that would be (b) above.

However, please do note (a): I expect that splitting things up will turn
out to be a mistake, as it has for other HW modules in the past. I would
far rather see a single hsp node in DT, since there is a single HSP
block in HW. Sure that block has multiple sub-functions. However, there
is common logic that affects all of those sub-functions and binds
everything into a single HW module. If you represent the HW module using
multiple different DT nodes, it will be hard to correctly represent that
common logic. Conversely, I see no real advantage to splitting up the DT
node. I strongly believe we should have a single "hsp" node in DT.

We have 6 HSP block in HW. FYI.

Internally, the SW driver for that node can be structured however you
want; it could register with multiple subsystems (mailbox, ...) with
just one struct device, or the HSP driver could be an MFD device with
sub-drivers for each separate piece of functionality the HW implements.
All this can easily be done even while using a single DT node. And
furthermore, we can add this SW structure later if/when we actually need
it; in other words, there's no need to change your current patches right
now, except to remove the nvidia,hsp-function DT property.

Thanks,
-Joseph