[POWERPC] Fix potential NULL dereference

This patch does fix potential NULL pointer dereference that could take
place inside of strcmp() if of_get_property() call failed.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

diff --git a/arch/powerpc/platforms/83xx/usb.c b/arch/powerpc/platforms/83xx/usb.c
index eafe760..b45160f 100644 (file)
--- a/arch/powerpc/platforms/83xx/usb.c
+++ b/arch/powerpc/platforms/83xx/usb.c
@@ -130,7 +130,7 @@ int mpc831x_usb_cfg(void)
        out_be32(immap + MPC83XX_SCCR_OFFS, temp);
 
        /* Configure pin mux for ULPI.  There is no pin mux for UTMI */
-       if (!strcmp(prop, "ulpi")) {
+       if (prop && !strcmp(prop, "ulpi")) {
                temp = in_be32(immap + MPC83XX_SICRL_OFFS);
                temp &= ~MPC831X_SICRL_USB_MASK;
                temp |= MPC831X_SICRL_USB_ULPI;
@@ -153,13 +153,13 @@ int mpc831x_usb_cfg(void)
        usb_regs = ioremap(res.start, res.end - res.start + 1);
 
        /* Using on-chip PHY */
-       if (!strcmp(prop, "utmi_wide") ||
-                       !strcmp(prop, "utmi")) {
+       if (prop && (!strcmp(prop, "utmi_wide") ||
+                    !strcmp(prop, "utmi"))) {
                /* Set UTMI_PHY_EN, REFSEL to 48MHZ */
                out_be32(usb_regs + FSL_USB2_CONTROL_OFFS,
                                CONTROL_UTMI_PHY_EN | CONTROL_REFSEL_48MHZ);
        /* Using external UPLI PHY */
-       } else if (!strcmp(prop, "ulpi")) {
+       } else if (prop && !strcmp(prop, "ulpi")) {
                /* Set PHY_CLK_SEL to ULPI */
                temp = CONTROL_PHY_CLK_SEL_ULPI;
 #ifdef CONFIG_USB_OTG