usb: musb: core: add pm_runtime_irq_safe()

commit 3e43a0725637299a14369e3ef109c25a8ec5c008 upstream.

We need a pm_runtime_get_sync() call from
within musb_gadget_pullup() to make sure
registers are accessible at that time.

The problem is that musb_gadget_pullup() is
called with IRQs disabled and, because of that,
we need to tell pm_runtime that this pm_runtime_get_sync()
is IRQ safe.

We can simply add pm_runtime_irq_safe(), however, because
we need to make our read/write accessor function pointers
have been initialized before trying to use them. This means
that all pm_runtime initialization for musb_core needs to
be moved down so that when we call pm_runtime_irq_safe(),
the pm_runtime_get_sync() that it calls on the parent, won't
cause a crash due to NULL musb_read/write accessors.

Reported-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index eff3c5cf84f48e8489c605d5bf24915809f109ca..a9ac102ee7a05ec6d1c18c090f8b71c65d839f02 100644 (file)
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1892,16 +1892,18 @@ musb_init_controller(struct device *dev, int nIrq, void __iomem *ctrl)
                goto fail0;
        }
 
-       pm_runtime_use_autosuspend(musb->controller);
-       pm_runtime_set_autosuspend_delay(musb->controller, 200);
-       pm_runtime_enable(musb->controller);
-
        spin_lock_init(&musb->lock);
        musb->board_set_power = plat->set_power;
        musb->min_power = plat->min_power;
        musb->ops = plat->platform_ops;
        musb->port_mode = plat->mode;
 
+       /* We need musb_read/write functions initialized for PM */
+       pm_runtime_use_autosuspend(musb->controller);
+       pm_runtime_set_autosuspend_delay(musb->controller, 200);
+       pm_runtime_irq_safe(musb->controller);
+       pm_runtime_enable(musb->controller);
+
        /* The musb_platform_init() call:
         *   - adjusts musb->mregs
         *   - sets the musb->isr