usb: musb: Fix sleeping function called from invalid context for hdrc glue

Commit 65b3f50ed6fa ("usb: musb: Add PM runtime support for MUSB DSPS
glue layer") wrongly added a call for pm_runtime_get_sync to otg_timer
that runs in softirq context. That causes a "BUG: sleeping function called
from invalid context" every time when polling the cable status:

[<c015ebb4>] (__might_sleep) from [<c0413d60>] (__pm_runtime_resume+0x9c/0xa0)
[<c0413d60>] (__pm_runtime_resume) from [<c04d0bc4>] (otg_timer+0x3c/0x254)
[<c04d0bc4>] (otg_timer) from [<c0191180>] (call_timer_fn+0xfc/0x41c)
[<c0191180>] (call_timer_fn) from [<c01915c0>] (expire_timers+0x120/0x210)
[<c01915c0>] (expire_timers) from [<c0191acc>] (run_timer_softirq+0xa4/0xdc)
[<c0191acc>] (run_timer_softirq) from [<c010168c>] (__do_softirq+0x12c/0x594)

I did not notice that as I did not have CONFIG_DEBUG_ATOMIC_SLEEP enabled.
And looks like also musb_gadget_queue() suffers from the same problem.

Let's fix the issue by using a list of delayed work then call it on
resume. Note that we want to do this only when musb core and it's
parent devices are awake, and we need to make sure the DSPS glue
timer is stopped as noted by Johan Hovold <johan@kernel.org>.
Note that we already are re-enabling the timer with mod_timer() in
dsps_musb_enable().

Later on we may be able to remove other delayed work in the musb driver
and just do it from pending_resume_work. But this should be done only
for delayed work that does not have other timing requirements beyond
just being run on resume.

Fixes: 65b3f50ed6fa ("usb: musb: Add PM runtime support for MUSB DSPS
glue layer")
Reported-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 29 insertions, 4 deletions

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 4042ea017985..910f50967627 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -1222,13 +1222,22 @@ void musb_ep_restart(struct musb *musb, struct musb_request *req)
 		rxstate(musb, req);
 }
 
+static int musb_ep_restart_resume_work(struct musb *musb, void *data)
+{
+	struct musb_request *req = data;
+
+	musb_ep_restart(musb, req);
+
+	return 0;
+}
+
 static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req,
 			gfp_t gfp_flags)
 {
 	struct musb_ep		*musb_ep;
 	struct musb_request	*request;
 	struct musb		*musb;
-	int			status = 0;
+	int			status;
 	unsigned long		lockflags;
 
 	if (!ep || !req)
@@ -1245,6 +1254,17 @@ static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req,
 	if (request->ep != musb_ep)
 		return -EINVAL;
 
+	status = pm_runtime_get(musb->controller);
+	if ((status != -EINPROGRESS) && status < 0) {
+		dev_err(musb->controller,
+			"pm runtime get failed in %s\n",
+			__func__);
+		pm_runtime_put_noidle(musb->controller);
+
+		return status;
+	}
+	status = 0;
+
 	trace_musb_req_enq(request);
 
 	/* request is mine now... */
@@ -1255,7 +1275,6 @@ static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req,
 
 	map_dma_buffer(request, musb, musb_ep);
 
-	pm_runtime_get_sync(musb->controller);
 	spin_lock_irqsave(&musb->lock, lockflags);
 
 	/* don't queue if the ep is down */
@@ -1271,8 +1290,14 @@ static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req,
 	list_add_tail(&request->list, &musb_ep->req_list);
 
 	/* it this is the head of the queue, start i/o ... */
-	if (!musb_ep->busy && &request->list == musb_ep->req_list.next)
-		musb_ep_restart(musb, request);
+	if (!musb_ep->busy && &request->list == musb_ep->req_list.next) {
+		status = musb_queue_resume_work(musb,
+						musb_ep_restart_resume_work,
+						request);
+		if (status < 0)
+			dev_err(musb->controller, "%s resume work: %i\n",
+				__func__, status);
+	}
 
 unlock:
 	spin_unlock_irqrestore(&musb->lock, lockflags);