net: dsa: use capital "OR" for multiple licenses in SPDX

Documentation/process/license-rules.rst and checkpatch expect the SPDX
identifier syntax for multiple licenses to use capital "OR". Correct it
to keep consistent format and avoid copy-paste issues.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: FLorian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230823085632.116725-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: b53: convert to phylink_pcs

Convert B53 to use phylink_pcs for the serdes rather than hooking it
into the MAC-layer callbacks.

Fixes: 81c1681cbb9f ("net: dsa: b53: mark as non-legacy")
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: b53: switch to using phylink_generic_validate()

Switch the Broadcom b53 driver to using the phylink_generic_validate()
implementation by removing its own .phylink_validate method and
associated code.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: b53: populate supported_interfaces and mac_capabilities

Populate the supported interfaces and MAC capabilities for the Broadcom
B53 DSA switches in preparation to using these for the generic
validation functionality.

The interface modes are derived from:
- b53_serdes_phylink_validate()
- SRAB mux configuration

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: b53: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style
in header file for Broadcom BCM53xx managed switch driver.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used)

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

net: dsa: b53: Fix B53_SERDES_DIGITAL_CONTROL offset

Maths went wrong, to get 0x20, we need to do 0x1e + (x) * 2, not 0x18,
fix that offset so we access the correct registers. This would make us
not access the correct SerDes Digital control words, status would be
fine and so we would not be correctly flipping between Fiber and SGMII
modes resulting in incorrect status words being pulled into the SerDes
digital status register.

Fixes: 0e01491de646 ("net: dsa: b53: Add SerDes support")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: b53: Fix build with B53_SRAB enabled and not B53_SERDES

In case B53_SRAB is enabled, but not B53_SERDES, we can get the
following linking error:

ERROR: "b53_serdes_init" [drivers/net/dsa/b53/b53_srab.ko] undefined!

We also need to ifdef the body of b53_srab_serdes_map_lane() since it
would not be used when B53_SERDES is disabled and that would produce a
warning.

Fixes: 0e01491de646 ("net: dsa: b53: Add SerDes support")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: b53: Add SerDes support

Add support for the Northstar Plus SerDes which is accessed through a
special page of the switch. Since this is something that most people
probably will not want to use, make it a configurable option with a
default on ARCH_BCM_NSP where it is the most useful currently.

The SerDes supports both SGMII and 1000baseX modes for both lanes, and
2500baseX for one of the lanes, and is internally looking like a
seemingly standard MII PHY, except for the few bits that got repurposed.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>