releases/4.19.54/net-sh_eth-fix-mdio-access-in-sh_eth_close-for-r-car.patch

   1 From 53f150b778e402590126a5b3539d7f2d6097e0aa Mon Sep 17 00:00:00 2001
   2 From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
   3 Date: Tue, 28 May 2019 13:10:46 +0900
   4 Subject: net: sh_eth: fix mdio access in sh_eth_close() for R-Car Gen2 and
   5  RZ/A1 SoCs
   6
   7 [ Upstream commit 315ca92dd863fecbffc0bb52ae0ac11e0398726a ]
   8
   9 The sh_eth_close() resets the MAC and then calls phy_stop()
  10 so that mdio read access result is incorrect without any error
  11 according to kernel trace like below:
  12
  13 ifconfig-216   [003] .n..   109.133124: mdio_access: ee700000.ethernet-ffffffff read  phy:0x01 reg:0x00 val:0xffff
  14
  15 According to the hardware manual, the RMII mode should be set to 1
  16 before operation the Ethernet MAC. However, the previous code was not
  17 set to 1 after the driver issued the soft_reset in sh_eth_dev_exit()
  18 so that the mdio read access result seemed incorrect. To fix the issue,
  19 this patch adds a condition and set the RMII mode register in
  20 sh_eth_dev_exit() for R-Car Gen2 and RZ/A1 SoCs.
  21
  22 Note that when I have tried to move the sh_eth_dev_exit() calling
  23 after phy_stop() on sh_eth_close(), but it gets worse (kernel panic
  24 happened and it seems that a register is accessed while the clock is
  25 off).
  26
  27 Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
  28 Signed-off-by: David S. Miller <davem@davemloft.net>
  29 Signed-off-by: Sasha Levin <sashal@kernel.org>
  30 ---
  31  drivers/net/ethernet/renesas/sh_eth.c | 4 ++++
  32  1 file changed, 4 insertions(+)
  33
  34 diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
  35 index f27a0dc8c563..5e3e6e262ba3 100644
  36 --- a/drivers/net/ethernet/renesas/sh_eth.c
  37 +++ b/drivers/net/ethernet/renesas/sh_eth.c
  38 @@ -1588,6 +1588,10 @@ static void sh_eth_dev_exit(struct net_device *ndev)
  39         sh_eth_get_stats(ndev);
  40         mdp->cd->soft_reset(ndev);
  41
  42 +       /* Set the RMII mode again if required */
  43 +       if (mdp->cd->rmiimode)
  44 +               sh_eth_write(ndev, 0x1, RMIIMODE);
  45 +
  46         /* Set MAC address again */
  47         update_mac_address(ndev);
  48  }
  49 --
  50 2.20.1
  51