[U-Boot] [PATCH v3] 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 a unaligned access problem, as Tom Rini mentioned
  - fix more places in the driver with NULL pointer problem
- changes for v3:
  - add comment from Mugunthan V N:
    - priv NULL pointer checks not needed

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 | 10 +++++++++-
 1 Datei geändert, 9 Zeilen hinzugefügt(+), 1 Zeile entfernt(-)

diff --git a/drivers/net/cpsw.c b/drivers/net/cpsw.c
index 9bab71a..39240d9 100644
--- a/drivers/net/cpsw.c
+++ b/drivers/net/cpsw.c
@@ -568,9 +568,14 @@ 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;
 
+	phy = priv->phydev;
+
+	if (!phy)
+		return;
+
 	phy_startup(phy);
 	*link = phy->link;
 
@@ -947,6 +952,9 @@ 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