• Johan Hovold's avatar
    USB: musb: fix external abort on suspend · 68596cc2
    Johan Hovold authored
    commit 082df8be upstream.
    
    Make sure that the controller is runtime resumed when system suspending
    to avoid an external abort when accessing the interrupt registers:
    
      Unhandled fault: external abort on non-linefetch (0x1008) at 0xd025840a
      ...
      [<c05481a4>] (musb_default_readb) from [<c0545abc>] (musb_disable_interrupts+0x84/0xa8)
      [<c0545abc>] (musb_disable_interrupts) from [<c0546b08>] (musb_suspend+0x38/0xb8)
      [<c0546b08>] (musb_suspend) from [<c04a57f8>] (platform_pm_suspend+0x3c/0x64)
    
    This is easily reproduced on a BBB by enabling the peripheral port only
    (as the host port may enable the shared clock) and keeping it
    disconnected so that the controller is runtime suspended. (Well, you
    would also need to the not-yet-merged am33xx-suspend patches by Dave
    Gerlach to be able to suspend the BBB.)
    
    This is a regression that was introduced by commit 1c4d0b4e ("usb:
    musb: Remove pm_runtime_set_irq_safe") which allowed the parent glue
    device to runtime suspend and thereby exposed a couple of older issues:
    
    Register accesses without explicitly making sure the controller is
    runtime resumed during suspend was first introduced by commit c338412b
    ("usb: musb: unconditionally save and restore the context on suspend")
    in 3.14.
    
    Commit a1fc1920 ("usb: musb: core: make sure musb is in RPM_ACTIVE on
    resume") later started setting the RPM status to active during resume,
    and this was also implicitly relying on the parent always being active.
    Since commit 71723f95 ("PM / runtime: print error when activating a
    child to unactive parent") this now also results in the following
    warning:
    
      musb-hdrc musb-hdrc.0: runtime PM trying to activate child device
        musb-hdrc.0 but parent (47401400.usb) is not active
    
    This patch has been verified on 4.13-rc2, 4.12 and 4.9 using a BBB
    (the dsps glue would always be active also in 4.8).
    
    Fixes: c338412b ("usb: musb: unconditionally save and restore the context on suspend")
    Fixes: a1fc1920 ("usb: musb: core: make sure musb is in RPM_ACTIVE on resume")
    Fixes: 1c4d0b4e ("usb: musb: Remove pm_runtime_set_irq_safe")
    Cc: Alan Stern <stern@rowland.harvard.edu>
    Cc: Daniel Mack <zonque@gmail.com>
    Cc: Dave Gerlach <d-gerlach@ti.com>
    Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
    Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Cc: Tony Lindgren <tony@atomide.com>
    Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
    Signed-off-by: default avatarBin Liu <b-liu@ti.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    68596cc2
musb_core.c 76.1 KB