From 9bc3eb94e1da2003c4ce82062810054be817e01a Mon Sep 17 00:00:00 2001
From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Date: Wed, 2 May 2018 22:55:52 +0300
Subject: [PATCH 1230/1795] sh_eth: WARN_ON() access to unimplemented TSU
 register

Commit 3365711df024 ("sh_eth: WARN on access to a register not implemented
in a particular chip") added  WARN_ON() to sh_eth_{read|write}() but not
to sh_eth_tsu_{read|write}(). Now that we've routed almost all TSU register
accesses  (except TSU_ADR{H|L}<n> -- which are special) thru the latter
pair of accessors, it makes sense to check for the unimplemented TSU
registers as well...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 627a0d20fa7b9e05ea4f42f47ea84d450dbbc96f)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/net/ethernet/renesas/sh_eth.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index b71f726abb53..f22f1af16d0e 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -442,12 +442,22 @@ static void sh_eth_modify(struct net_device *ndev, int enum_index, u32 clear,
 static void sh_eth_tsu_write(struct sh_eth_private *mdp, u32 data,
 			     int enum_index)
 {
-	iowrite32(data, mdp->tsu_addr + mdp->reg_offset[enum_index]);
+	u16 offset = mdp->reg_offset[enum_index];
+
+	if (WARN_ON(offset == SH_ETH_OFFSET_INVALID))
+		return;
+
+	iowrite32(data, mdp->tsu_addr + offset);
 }
 
 static u32 sh_eth_tsu_read(struct sh_eth_private *mdp, int enum_index)
 {
-	return ioread32(mdp->tsu_addr + mdp->reg_offset[enum_index]);
+	u16 offset = mdp->reg_offset[enum_index];
+
+	if (WARN_ON(offset == SH_ETH_OFFSET_INVALID))
+		return ~0U;
+
+	return ioread32(mdp->tsu_addr + offset);
 }
 
 static void sh_eth_select_mii(struct net_device *ndev)
-- 
2.19.0