[PATCH net v3] net: dsa: realtek-smi: fix indirect reg access for ports>3

[luizluca@gmail.com]

From: Luiz Angelo Daros de Luca <luizluca@gmail.com>

This switch family can have up to 8 UTP ports {0..7}. However,
INDIRECT_ACCESS_ADDRESS_PHYNUM_MASK was using 2 bits instead of 3,
dropping the most significant bit during indirect register reads and
writes. Reading or writing ports 4, 5, 6, and 7 registers was actually
manipulating, respectively, ports 0, 1, 2, and 3 registers.

This is not sufficient but necessary to support any variant with more
than 4 UTP ports, like RTL8367S.

rtl8365mb_phy_{read,write} will now returns -EINVAL if phy is greater
than 7.

Fixes: 4af2950c50c8 ("net: dsa: realtek-smi: add rtl8365mb subdriver for RTL8365MB-VC")
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
---
 drivers/net/dsa/rtl8365mb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/rtl8365mb.c b/drivers/net/dsa/rtl8365mb.c
index baaae97283c5..078ca4cd7160 100644
--- a/drivers/net/dsa/rtl8365mb.c
+++ b/drivers/net/dsa/rtl8365mb.c
@@ -107,6 +107,7 @@
 #define RTL8365MB_LEARN_LIMIT_MAX_8365MB_VC	2112
 
 /* Family-specific data and limits */
+#define RTL8365MB_PHYADDRMAX	7
 #define RTL8365MB_NUM_PHYREGS	32
 #define RTL8365MB_PHYREGMAX	(RTL8365MB_NUM_PHYREGS - 1)
 #define RTL8365MB_MAX_NUM_PORTS	(RTL8365MB_CPU_PORT_NUM_8365MB_VC + 1)
@@ -176,7 +177,7 @@
 #define RTL8365MB_INDIRECT_ACCESS_STATUS_REG			0x1F01
 #define RTL8365MB_INDIRECT_ACCESS_ADDRESS_REG			0x1F02
 #define   RTL8365MB_INDIRECT_ACCESS_ADDRESS_OCPADR_5_1_MASK	GENMASK(4, 0)
-#define   RTL8365MB_INDIRECT_ACCESS_ADDRESS_PHYNUM_MASK		GENMASK(6, 5)
+#define   RTL8365MB_INDIRECT_ACCESS_ADDRESS_PHYNUM_MASK		GENMASK(7, 5)
 #define   RTL8365MB_INDIRECT_ACCESS_ADDRESS_OCPADR_9_6_MASK	GENMASK(11, 8)
 #define   RTL8365MB_PHY_BASE					0x2000
 #define RTL8365MB_INDIRECT_ACCESS_WRITE_DATA_REG		0x1F03
@@ -679,6 +680,9 @@ static int rtl8365mb_phy_read(struct realtek_smi *smi, int phy, int regnum)
 	u16 val;
 	int ret;
 
+	if (phy > RTL8365MB_PHYADDRMAX)
+		return -EINVAL;
+
 	if (regnum > RTL8365MB_PHYREGMAX)
 		return -EINVAL;
 
@@ -704,6 +708,9 @@ static int rtl8365mb_phy_write(struct realtek_smi *smi, int phy, int regnum,
 	u32 ocp_addr;
 	int ret;
 
+	if (phy > RTL8365MB_PHYADDRMAX)
+		return -EINVAL;
+
 	if (regnum > RTL8365MB_PHYREGMAX)
 		return -EINVAL;
 
-- 
2.33.1