Hi Rob,

On 12/5/18 18:16, Rob Herring wrote:

On Tue, Nov 27, 2018 at 12:03 PM Georgi Djakov [off-list ref] wrote:

quoted

This patch introduces a new API to get requirements and configure the
interconnect buses across the entire chipset to fit with the current
demand.

The API is using a consumer/provider-based model, where the providers are
the interconnect buses and the consumers could be various drivers.
The consumers request interconnect resources (path) between endpoints and
set the desired constraints on this data flow path. The providers receive
requests from consumers and aggregate these requests for all master-slave
pairs on that path. Then the providers configure each participating in the
topology node according to the requested data flow path, physical links and
constraints. The topology could be complicated and multi-tiered and is SoC
specific.

Signed-off-by: Georgi Djakov <redacted>
Reviewed-by: Evan Green <redacted>

[...]

quoted

+struct icc_path *icc_get(struct device *dev, const int src_id,
+                        const int dst_id);
+void icc_put(struct icc_path *path);
+int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw);

icc_set() is very generic, but this function isn't easily extended to
other parameters than bandwidth. Perhaps icc_set_bandwidth() instead.
Then when you add some other setting, you just add a new function. Of
course, if you wind up with a bunch of different parameters, then
you'll probably need an atomic type interface where you test all the
settings together and then commit them separately in one call. But

Thanks for the comment. We have already started some discussion with the
Nvidia guys about supporting also latency and priority. We can do a
structure based approach and pass a struct with all the bandwidth /
latency / priority stuff to a function like icc_set_extended(); It's
very early for any conclusions yet and for now we support only
bandwidth. The function name still can be easy changed with a follow-up
patch until one is using it yet. Let me think again.

from a DT perspective, I certainly hope there are not lots of new
settings folks want to add. 

Regarding DT, all settings should go into the drivers for now and
later we can decide if something makes sense to be really in device-tree.

Thanks,
Georgi