powerpc/usb: fix issue of CPU halt when missing USB PHY clock

when missing USB PHY clock, kernel booting up will halt during USB
initialization. We should check USBGP[PHY_CLK_VALID] bit to avoid
CPU hang in this case.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 10 insertions, 2 deletions

diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index b556a72264d1..c26a82e83f6e 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/drivers/usb/host/ehci-fsl.c
@@ -239,7 +239,7 @@ static void ehci_fsl_setup_phy(struct ehci_hcd *ehci,
         ehci_writel(ehci, portsc, &ehci->regs->port_status[port_offset]);
 }
 
-static void ehci_fsl_usb_setup(struct ehci_hcd *ehci)
+static int ehci_fsl_usb_setup(struct ehci_hcd *ehci)
 {
         struct usb_hcd *hcd = ehci_to_hcd(ehci);
         struct fsl_usb2_platform_data *pdata;
@@ -299,12 +299,19 @@ static void ehci_fsl_usb_setup(struct ehci_hcd *ehci)
 #endif
                 out_be32(non_ehci + FSL_SOC_USB_SICTRL, 0x00000001);
         }
+
+        if (!(in_be32(non_ehci + FSL_SOC_USB_CTRL) & CTRL_PHY_CLK_VALID)) {
+                printk(KERN_WARNING "fsl-ehci: USB PHY clock invalid\n");
+                return -ENODEV;
+        }
+        return 0;
 }
 
 /* called after powerup, by probe or system-pm "wakeup" */
 static int ehci_fsl_reinit(struct ehci_hcd *ehci)
 {
-        ehci_fsl_usb_setup(ehci);
+        if (ehci_fsl_usb_setup(ehci))
+                return -ENODEV;
         ehci_port_power(ehci, 0);
 
         return 0;
diff --git a/drivers/usb/host/ehci-fsl.h b/drivers/usb/host/ehci-fsl.h
index 491806221165..bdf43e2adc51 100644
--- a/drivers/usb/host/ehci-fsl.h
+++ b/drivers/usb/host/ehci-fsl.h
@@ -45,5 +45,6 @@
 #define FSL_SOC_USB_PRICTRL     0x40c   /* NOTE: big-endian */
 #define FSL_SOC_USB_SICTRL      0x410   /* NOTE: big-endian */
 #define FSL_SOC_USB_CTRL        0x500   /* NOTE: big-endian */
+#define CTRL_PHY_CLK_VALID      (1 << 17)
 #define SNOOP_SIZE_2GB          0x1e
 #endif                          /* _EHCI_FSL_H */