net: dsa: mv88e6xxx: don't use PHY_DETECT on internal PHY's

stable inclusion
from stable-5.10.75
commit 3e287365216330ba5041f7fa1369460ad716f422
bugzilla: 182987 https://gitee.com/openeuler/kernel/issues/I4I3MP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e287365216330ba5041f7fa1369460ad716f422



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commit 4a3e0aed upstream.

mv88e6xxx_port_ppu_updates() interpretes data in the PORT_STS
register incorrectly for internal ports (ie no PPU). In these
cases, the PHY_DETECT bit indicates link status. This results
in forcing the MAC state whenever the PHY link goes down which
is not intended. As a side effect, LED's configured to show
link status stay lit even though the physical link is down.

Add a check in mac_link_down and mac_link_up to see if it
concerns an external port and only then, look at PPU status.

Fixes: 5d5b231d (net: dsa: mv88e6xxx: use PHY_DETECT in mac_link_up/mac_link_down)
Reported-by: Maarten Zanders <m.zanders@televic.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Maarten Zanders <maarten.zanders@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>