Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 16 Jan 2023 10:51:48 +0100 | From | Lukasz Majewski <> | Subject | Re: [PATCH v4 1/3] dsa: marvell: Provide per device information about max frame size |
| |
Hi Russell,
> On Fri, Jan 06, 2023 at 11:16:49AM +0100, Lukasz Majewski wrote: > > Different Marvell DSA switches support different size of max frame > > bytes to be sent. This value corresponds to the memory allocated > > in switch to store single frame. > > > > For example mv88e6185 supports max 1632 bytes, which is now > > in-driver standard value. On the other hand - mv88e6250 supports > > 2048 bytes. To be more interresting - devices supporting jumbo > > frames - use yet another value (10240 bytes) > > > > As this value is internal and may be different for each switch IC, > > new entry in struct mv88e6xxx_info has been added to store it. > > > > This commit doesn't change the code functionality - it just provides > > the max frame size value explicitly - up till now it has been > > assigned depending on the callback provided by the IC driver > > (e.g. .set_max_frame_size, .port_set_jumbo_size). > > I don't think this patch is correct. > > One of the things that mv88e6xxx_setup_port() does when initialising > each port is: > > if (chip->info->ops->port_set_jumbo_size) { > err = chip->info->ops->port_set_jumbo_size(chip, > port, 10218); if (err) > return err; > } > > There is one implementation of this, which is > mv88e6165_port_set_jumbo_size() and that has the effect of setting > port register 8 to the largest size. So any chip that supports the > port_set_jumbo_size() method will be programmed on initialisation to > support this larger size. > > However, you seem to be listing e.g. the 88e6190 (if I'm interpreting > the horrid mv88e6xxx_table changes correctly)
Those changes were requested by the community. Previous versions of this patch were just changing things to allow correct operation of the switch ICs on which I do work (i.e. 88e6020 and 88e6071).
And yes, for 88e6190 the max_frame_size = 10240, but (by mistake) the same value was not updated for 88e6190X.
The question is - how shall I proceed?
After the discussion about this code - it looks like approach from v3 [1] seems to be the most non-intrusive for other ICs.
> as having a maximum > frame size of 1522, but it implements this method, supports 10240, and > thus is programmed to support frames of that size rather than 1522. >
Links:
[1] - https://lore.kernel.org/netdev/Y7M+mWMU+DJPYubp@lunn.ch/T/
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de [unhandled content-type:application/pgp-signature] | ![\](/images/icornerr.gif) |