Yoshihiro Shimoda da39ca31bc net: sh_eth: fix mdio access in sh_eth_close() for R-Car Gen2 and RZ/A1 SoCs
[ Upstream commit 315ca92dd863fecbffc0bb52ae0ac11e0398726a ]

The sh_eth_close() resets the MAC and then calls phy_stop()
so that mdio read access result is incorrect without any error
according to kernel trace like below:

ifconfig-216   [003] .n..   109.133124: mdio_access: ee700000.ethernet-ffffffff read  phy:0x01 reg:0x00 val:0xffff

According to the hardware manual, the RMII mode should be set to 1
before operation the Ethernet MAC. However, the previous code was not
set to 1 after the driver issued the soft_reset in sh_eth_dev_exit()
so that the mdio read access result seemed incorrect. To fix the issue,
this patch adds a condition and set the RMII mode register in
sh_eth_dev_exit() for R-Car Gen2 and RZ/A1 SoCs.

Note that when I have tried to move the sh_eth_dev_exit() calling
after phy_stop() on sh_eth_close(), but it gets worse (kernel panic
happened and it seems that a register is accessed while the clock is
off).

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-22 08:16:18 +02:00
2019-06-22 08:16:15 +02:00
2019-06-19 08:21:00 +02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
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Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
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