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, 26 insertions, 10 deletions

diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
index 0f17d2140db6..6096c84ab67a 100644
--- a/drivers/usb/musb/musb_dsps.c
+++ b/drivers/usb/musb/musb_dsps.c
@@ -185,24 +185,19 @@ static void dsps_musb_disable(struct musb *musb)
 	musb_writel(reg_base, wrp->coreintr_clear, wrp->usb_bitmap);
 	musb_writel(reg_base, wrp->epintr_clear,
 			 wrp->txep_bitmap | wrp->rxep_bitmap);
+	del_timer_sync(&glue->timer);
 	musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
 }
 
-static void otg_timer(unsigned long _musb)
+/* Caller must take musb->lock */
+static int dsps_check_status(struct musb *musb, void *unused)
 {
-	struct musb *musb = (void *)_musb;
 	void __iomem *mregs = musb->mregs;
 	struct device *dev = musb->controller;
 	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
 	const struct dsps_musb_wrapper *wrp = glue->wrp;
 	u8 devctl;
-	unsigned long flags;
 	int skip_session = 0;
-	int err;
-
-	err = pm_runtime_get_sync(dev);
-	if (err < 0)
-		dev_err(dev, "Poll could not pm_runtime_get: %i\n", err);
 
 	/*
 	 * We poll because DSPS IP's won't expose several OTG-critical
@@ -212,7 +207,6 @@ static void otg_timer(unsigned long _musb)
 	dev_dbg(musb->controller, "Poll devctl %02x (%s)\n", devctl,
 				usb_otg_state_string(musb->xceiv->otg->state));
 
-	spin_lock_irqsave(&musb->lock, flags);
 	switch (musb->xceiv->otg->state) {
 	case OTG_STATE_A_WAIT_VRISE:
 		mod_timer(&glue->timer, jiffies +
@@ -245,8 +239,30 @@ static void otg_timer(unsigned long _musb)
 	default:
 		break;
 	}
-	spin_unlock_irqrestore(&musb->lock, flags);
 
+	return 0;
+}
+
+static void otg_timer(unsigned long _musb)
+{
+	struct musb *musb = (void *)_musb;
+	struct device *dev = musb->controller;
+	unsigned long flags;
+	int err;
+
+	err = pm_runtime_get(dev);
+	if ((err != -EINPROGRESS) && err < 0) {
+		dev_err(dev, "Poll could not pm_runtime_get: %i\n", err);
+		pm_runtime_put_noidle(dev);
+
+		return;
+	}
+
+	spin_lock_irqsave(&musb->lock, flags);
+	err = musb_queue_resume_work(musb, dsps_check_status, NULL);
+	if (err < 0)
+		dev_err(dev, "%s resume work: %i\n", __func__, err);
+	spin_unlock_irqrestore(&musb->lock, flags);
 	pm_runtime_mark_last_busy(dev);
 	pm_runtime_put_autosuspend(dev);
 }