Re: [PATCH net v2] net: ti: icssg-prueth: Fix buffer allocation for ICSSG

[Simon Horman <horms@kernel.org>]

On Tue, Jul 15, 2025 at 12:37:45PM +0530, MITTAL, HIMANSHU wrote:

...

> > > +-----+-----------------------------------------------+
> > > |     |       SLICE 0       |        SLICE 1          |
> > > |     +------------+----------+------------+----------+
> > > |     | Start addr | End addr | Start addr | End addr |
> > > +-----+------------+----------+------------+----------+
> > > | EXP | 70024000   | 70028000 | 7002C000   | 70030000 | <-- Overlapping
> > Thanks for the detailed explanation with these tables.
> > It is very helpful. I follow both the existing and new mappings
> > with their help. Except for one thing.
> > 
> > It's not clear how EXP was set to the values on the line above.
> > Probably I'm missing something very obvious.
> > Could you help me out here?
> 
> The root cause for this issue is that, buffer configuration for Express
> Frames
> in function: prueth_fw_offload_buffer_setup() is missing.
> 
> 
> Details:
> The driver implements two distinct buffer configuration functions that are
> invoked
> based on the driver state and ICSSG firmware:-
> prueth_fw_offload_buffer_setup()
> - prueth_emac_buffer_setup()
> 
> During initialization, the driver creates standard network interfaces
> (netdevs) and
> configures buffers via prueth_emac_buffer_setup(). This function properly
> allocates
> and configures all required memory regions including:
> - LI buffers
> - Express packet buffers
> - Preemptible packet buffers
> 
> However, when the driver transitions to an offload mode (switch/HSR/PRP),
> buffer reconfiguration is handled by prueth_fw_offload_buffer_setup().
> This function does not reconfigure the buffer regions required for Express
> packets,
> leading to incorrect buffer allocation.

Thanks for your patience, I see that now :)

I'm sorry to drag this out, but I do think it would be useful to add
information above the lines of the above to the patch description.

> > > | PRE | 70030000   | 70033800 | 70034000   | 70037800 |
> > > +-----+------------+----------+------------+----------+
> > > 
> > > +---------------------+----------+----------+
> > > |                     | SLICE 0  |  SLICE 1 |
> > > +---------------------+----------+----------+
> > > | Default Drop Offset | 00000000 | 00000000 |     <-- Field not configured
> > > +---------------------+----------+----------+
> > ...

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