[U-Boot] [PATCH v2] net, phy, cpsw: fix NULL pointer deference

[Heiko Schocher]

if phy_connect() did not find a phy, phydev is NULL and
following code in cpsw_phy_init() crashes. Fix this.

Signed-off-by: Heiko Schocher <hs at denx.de>
Cc: Joe Hershberger <joe.hershberger at gmail.com>
Cc: Mugunthan V N <mugunthanvnm at ti.com>
Cc: Tom Rini <trini at ti.com>

---
- changes for v2:
  - change commit message as it is a NULL pointer deference error
    not an unaligned access problem, as Tom Rini mentioned
  - fix more places in the driver with NULL pointer problem

Found on the dxr2 board with no phy connected to the board,
U-Boot crashes with:

U-Boot 2013.07-12701-gea98378-dirty (Sep 04 2013 - 06:58:16)

I2C:   ready
DRAM:  128 MiB
Enable d-cache
FactorySet is not right in eeprom.
NAND:  256 MiB
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
8-bit BCH HW ECC selected
Net:   Could not get PHY for cpsw: addr 0
data abort

    MAYBE you should read doc/README.arm-unaligned-accesses

pc : [<87f80574>]          lr : [<87f80fcc>]
sp : 86f5aee0  ip : 00000034     fp : 80100020
r10: 00000014  r9 : 07e5d000     r8 : 86f5af30
r7 : 86f5f750  r6 : 86f5f804     r5 : 86f5f708  r4 : 86f5f750
r3 : 00000000  r2 : 00000000     r1 : 87fa4d08  r0 : 00000000
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32
Resetting CPU ...
---
 drivers/net/cpsw.c | 26 +++++++++++++++++++++++++-
 1 Datei geändert, 25 Zeilen hinzugefügt(+), 1 Zeile entfernt(-)

diff --git a/drivers/net/cpsw.c b/drivers/net/cpsw.c
index 9bab71a..186665b 100644
--- a/drivers/net/cpsw.c
+++ b/drivers/net/cpsw.c
@@ -561,6 +561,9 @@ static inline void setbit_and_wait_for_clear32(void *addr)
 static void cpsw_set_slave_mac(struct cpsw_slave *slave,
 			       struct cpsw_priv *priv)
 {
+	if (!priv)
+		return;
+
 	__raw_writel(mac_hi(priv->dev->enetaddr), &slave->regs->sa_hi);
 	__raw_writel(mac_lo(priv->dev->enetaddr), &slave->regs->sa_lo);
 }
@@ -568,9 +571,17 @@ static void cpsw_set_slave_mac(struct cpsw_slave *slave,
 static void cpsw_slave_update_link(struct cpsw_slave *slave,
 				   struct cpsw_priv *priv, int *link)
 {
-	struct phy_device *phy = priv->phydev;
+	struct phy_device *phy;
 	u32 mac_control = 0;
 
+	if (!priv)
+		return;
+
+	phy = priv->phydev;
+
+	if (!phy)
+		return;
+
 	phy_startup(phy);
 	*link = phy->link;
 
@@ -604,8 +615,12 @@ static int cpsw_update_link(struct cpsw_priv *priv)
 	int link = 0;
 	struct cpsw_slave *slave;
 
+	if (!priv)
+		return -1;
+
 	for_each_slave(slave, priv)
 		cpsw_slave_update_link(slave, priv, &link);
+
 	priv->mdio_link = readl(&mdio_regs->link);
 	return link;
 }
@@ -614,6 +629,9 @@ static int cpsw_check_link(struct cpsw_priv *priv)
 {
 	u32 link = 0;
 
+	if (!priv)
+		return -1;
+
 	link = __raw_readl(&mdio_regs->link) & priv->phy_mask;
 	if ((link) && (link == priv->mdio_link))
 		return 1;
@@ -623,6 +641,9 @@ static int cpsw_check_link(struct cpsw_priv *priv)
 
 static inline u32  cpsw_get_slave_port(struct cpsw_priv *priv, u32 slave_num)
 {
+	if (!priv)
+		return -1;
+
 	if (priv->host_port == 0)
 		return slave_num + 1;
 	else
@@ -947,6 +968,9 @@ static int cpsw_phy_init(struct eth_device *dev, struct cpsw_slave *slave)
 			dev,
 			slave->data->phy_if);
 
+	if (!phydev)
+		return -1;
+
 	phydev->supported &= supported;
 	phydev->advertising = phydev->supported;
 
-- 
1.7.11.7