usb: dwc3: core: avoid NULL pointer dereference

commit 3e10a2ce98d1 ("usb: dwc3: add hsphy_interface
property") introduced a possible NULL pointer
dereference because dwc->hsphy_interface can be
NULL.

In order to fix it, all we have to do is guard
strncmp() against a NULL argument.

Fixes: 3e10a2ce98d1 ("usb: dwc3: add hsphy_interface property")
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 5c110d8e293b..ff5773c66b84 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -446,10 +446,12 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
         /* Select the HS PHY interface */
         switch (DWC3_GHWPARAMS3_HSPHY_IFC(dwc->hwparams.hwparams3)) {
         case DWC3_GHWPARAMS3_HSPHY_IFC_UTMI_ULPI:
-                if (!strncmp(dwc->hsphy_interface, "utmi", 4)) {
+                if (dwc->hsphy_interface &&
+                                !strncmp(dwc->hsphy_interface, "utmi", 4)) {
                         reg &= ~DWC3_GUSB2PHYCFG_ULPI_UTMI;
                         break;
-                } else if (!strncmp(dwc->hsphy_interface, "ulpi", 4)) {
+                } else if (dwc->hsphy_interface &&
+                                !strncmp(dwc->hsphy_interface, "ulpi", 4)) {
                         reg |= DWC3_GUSB2PHYCFG_ULPI_UTMI;
                         dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
                 } else {