• Al Cooper's avatar
    phy: phy-brcm-usb-init: DRD mode can cause crash on startup · 0aa0c122
    Al Cooper authored
    This is caused by a bug in the BDC core. When the BDC core comes
    out of reset and it's not selected, it gets a backup clock. When
    the BDC core is selected, it get's the main clock. If HOST mode
    is then selected the BDC core has the main clock shut off but
    the backup clock is not restored.
    
    The failure scenario and cause are as follows:
    - DRD mode is active
    - Device mode is selected first in bootloader
    - When host mode is now selected, the clock to the BDC is cut off.
    - BDC registers are inaccessible and therefore the BDC driver
      crashes upon Linux boot.
    
    The fix is to have the phy driver always force a BDC reset on
    startup.
    
    Fixes: 49859e55 ("phy: usb: phy-brcm-usb: Add Broadcom STB USB phy driver")
    Signed-off-by: default avatarAl Cooper <alcooperx@gmail.com>
    Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
    Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
    0aa0c122
phy-brcm-usb-init.c 32.6 KB