Hi Michael, michael@xxxxxxxx wrote on Fri, 28 Oct 2022 15:33:31 +0200: > Am 2022-10-28 11:23, schrieb Miquel Raynal: > > The ONIE standard describes the organization of tlv (type-length-value) > > arrays commonly stored within NVMEM devices on common networking > > hardware. > > > > Several drivers already make use of NVMEM cells for purposes like > > retrieving a default MAC address provided by the manufacturer. > > > > What made ONIE tables unusable so far was the fact that the information > > where "dynamically" located within the table depending on the > > manufacturer wishes, while Linux NVMEM support only allowed statically > > defined NVMEM cells. Fortunately, this limitation was eventually > tackled > > with the introduction of discoverable cells through the use of NVMEM > > layouts, making it possible to extract and consistently use the content > > of tables like ONIE's tlv arrays. > > > > Parsing this table at runtime in order to get various information is > now > > possible. So, because many Marvell networking switches already follow > > this standard, let's consider using NVMEM cells as a new valid source > of > > information when looking for a base MAC address, which is one of the > > primary uses of these new fields. Indeed, manufacturers following the > > ONIE standard are encouraged to provide a default MAC address there, so > > let's eventually use it if no other MAC address has been found using > the > > existing methods. > > > > Link: > https://opencomputeproject.github.io/onie/design-spec/hw_requirements.html > > Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx> > > --- > > > > Hello, I suppose my change is safe but I don't want to break existing > > setups so a review on this would be welcome! > > > > drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > > b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > > index eb0fb8128096..7c8c323f4411 100644 > > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > > @@ -6104,6 +6104,12 @@ static void mvpp2_port_copy_mac_addr(struct > > net_device *dev, struct mvpp2 *priv, > > } > > } > > > > + if (!of_get_mac_address(to_of_node(fwnode), hw_mac_addr)) { > > Mh, the driver already does a fwnode_get_mac_address() which might > fetch it from OF. But that variant doesn't try to get the mac address > via nvmem; in contrast to the of_get_mac_address() variant which will > also try NVMEM. > Maybe it would be better to just use device_get_ethdev_address() and > extend that one to also try the nvmem store. Just to align all the > different variants to get a mac address. Actually this choice was made on purpose: I am adding this method to retrieve the MAC address only if no other way has succeeded. I don't know if the MAC addresses are expected to remain stable over time, I assumed it was somehow part of the ABI. Using device_get_ethdev_address() with support for MAC addresses in nvmem cells would possibly change the MAC address of many existing devices after an update because we found a MAC address in the tlv table before checking the device's own registers (as in this driver) So I assumed it was better avoiding changing the MAC address providers order in the probe... Thanks, Miquèl
