qca-ssdk: fix unsupported scenario with PORT1 not declared in switch bmp

qca-ssdk: fix unsupported scenario with PORT1 not declared in switch bmp

Commit 947b44d ("ipq807x: fix wrong define for LAN and WAN ess mask")
started fixing wrong switch_lan_bmp that defined lan there weren't
actually present. This displayed a fragility in the malibu phy init code
in qca-ssdk.

Add patch to fix this. Also update each DTS with the new required
property if needed.

The new binding malibu_phy_start_addr is required with devices that
place the malibu first PHY referring port1 on a different PHY addres
than 0. The most common configuration is 0 but some device (for example
Qnap 301W) place the malibu PHY at an offset to address 16.

Refer to ipq8074-ess dtsi for extensive description on how to derive
this value.

Quoting the patch detailed description:

The usage of first_phy_addr is EXTREMELY FRAGILE and results
in dangerous results if the OEM (or anyone that by chance try to
implement things in a logical manner) deviates from the default values
from the "magical template".

To be in more details. With QSDK 12.4, some tweaks were done to improve
autoneg and now on every call of port status, the phydev is tried to
add. This resulted in the call and log spam of an error with ports that
are actually not present on the system with qsdk reporting phydev is
NULL. This itself is not an error and printing the error is correct.

What is actually an error from ages is setting generic bitmap reporting
presence of port that are actually not present. This is very common on
OEM where the switch_lan_bmp is always a variant of 0x1e (that on bitmap
results in PORT1 PORT2 PORT3 PORT4 present) or 0x3e (PORT1 PORT2 PORT3
PORT4 PORT5). Reality is that many device are used as AP with one LAN
port or one WAN port. (or even exotic configuration with PORT1 not
present and PORT2 PORT3 PORT4 present (Xiaomi 3600)

With this finding one can say... ok nice, then lets update the DT and
set the correct bitmap...

Again world is a bad place and reality is that this cause wonderful
regression in some case of by extreme luck the first ever connected
port working and the rest of the switch dead.

The problem has been bisected to all the device that doesn't have the
PORT1 declared in any of the bitmap.

With this prefaction in mind, on to the REAL problem.

malibu_phy_hw_init FOR SOME REASON, set a global variable first_phy_addr
to the first detected PHY addr that coincidentally is always PORT1.
PORT1 addr is 0x0. The entire code in malibu_phy use this variable to
derive the phy addrs in some function.

Declaring a bitmap where the PORT1 is missing (or worse PORT4 the only
one connected) result in first_phy_addr set to 1 or whatever phy addr is
detected first setting wrong value all over the init stage.

To fix this, introduce a new binding malibu_first_phy_addr to manually
declare the first phy that the malibu PHY driver should use and permit
to detach it from port bmp detection. The legacy detection is kept for
compatibility reason.

Fixes: #13945
Fixes: 947b44d9ae17 ("ipq807x: fix wrong define for LAN and WAN ess mask")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Tested-by: Robert Marko <robimarko@gmail.com> # Qnap 301W
Reviewed-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>