net: fec: limit register access on i.MX6UL

stable inclusion
from stable-v5.10.153
commit 97262705c0cb067c0f9bd055edfe115f7f43913c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97262705c0cb067c0f9bd055edfe115f7f43913c



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[ Upstream commit 0a8b43b1 ]

Using 'ethtool -d […]' on an i.MX6UL leads to a kernel crash:

   Unhandled fault: external abort on non-linefetch (0x1008) at […]

due to this SoC has less registers in its FEC implementation compared to other
i.MX6 variants. Thus, a run-time decision is required to avoid access to
non-existing registers.

Fixes: a51d3ab5 ("net: fec: use a more proper compatible string for i.MX6UL type device")
Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20221024080552.21004-1-jbe@pengutronix.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lipeng Sang <sanglipeng1@jd.com>