Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

This patch fixes the following warning:

drivers/net/dsa/microchip/ksz9477.c: In function ‘ksz9477_get_interface’:
drivers/net/dsa/microchip/ksz9477.c:1145:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (gbit)
      ^
drivers/net/dsa/microchip/ksz9477.c:1147:2: note: here
  case 0:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add KSZ9893 switch support in KSZ9477 driver.  This switch is similar to
KSZ9477 except the ingress tail tag has 1 byte instead of 2 bytes, so
KSZ9893 tagging will be used.

The XMII register that governs how the host port communicates with the
MAC also has different register definitions.

Signed-off-by: Tristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

No current DSA driver makes use of the phydev parameter passed to the
disable_port call. Remove it.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add port_cleanup function to reset some device variables when the port is
disabled.  Add a mutex to make sure changing those variables is
thread-safe.

Signed-off-by: Tristram Ha <Tristram.Ha@microchip.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove unnecessary header include.

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

Get port link status to know whether to read MIB counters when the link
is going down.

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

Add background MIB counter reading support.

Port MIB counters should only be read when there is link.  Otherwise it is
a waste of time as hardware never increases those counters.  There are
exceptions as some switches keep track of dropped counts no matter what.

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

Prepare PHY for proper advertisement as sometimes the PHY in the switch
has its own problems even though it may share the PHY id from regular PHY
but the fixes in the PHY driver do not apply.

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

The flag offload_fwd_mark is set as the switch can forward frames by
itself.

This can be considered a fix to a problem introduced in commit
c2e866911e254067 where the port membership are not set in sync.  The flag
offload_fwd_mark just needs to be set in tag_ksz.c to prevent the software
bridge from forwarding duplicate multicast frames.

Fixes: c2e866911e254067 ("microchip: break KSZ9477 DSA driver into two files")
Signed-off-by: Tristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>