patch "USB: musb: fix external abort on suspend" added to usb-next

patch "USB: musb: fix external abort on suspend" added to usb-next

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: musb: fix external abort on suspend

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


>From 082df8be455ade361748f0385aa6c9c8d07be167 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 24 Aug 2017 11:38:36 -0500
Subject: USB: musb: fix external abort on suspend

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 1c4d0b4e1806 ("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 c338412b5ded
("usb: musb: unconditionally save and restore the context on suspend")
in 3.14.

Commit a1fc1920aaaa ("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 71723f95463d ("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: c338412b5ded ("usb: musb: unconditionally save and restore the context on suspend")
Fixes: a1fc1920aaaa ("usb: musb: core: make sure musb is in RPM_ACTIVE on resume")
Fixes: 1c4d0b4e1806 ("usb: musb: Remove pm_runtime_set_irq_safe")
Cc: stable <stable@vger.kernel.org>	# 4.8+
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: Johan Hovold <johan@kernel.org>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/musb/musb_core.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 5e6f2b44e33f..029692053dd3 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2671,6 +2671,13 @@ static int musb_suspend(struct device *dev)
 {
 	struct musb	*musb = dev_to_musb(dev);
 	unsigned long	flags;
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		return ret;
+	}
 
 	musb_platform_disable(musb);
 	musb_disable_interrupts(musb);
@@ -2721,14 +2728,6 @@ static int musb_resume(struct device *dev)
 	if ((devctl & mask) != (musb->context.devctl & mask))
 		musb->port1_status = 0;
 
-	/*
-	 * The USB HUB code expects the device to be in RPM_ACTIVE once it came
-	 * out of suspend
-	 */
-	pm_runtime_disable(dev);
-	pm_runtime_set_active(dev);
-	pm_runtime_enable(dev);
-
 	musb_start(musb);
 
 	spin_lock_irqsave(&musb->lock, flags);
@@ -2738,6 +2737,9 @@ static int musb_resume(struct device *dev)
 			error);
 	spin_unlock_irqrestore(&musb->lock, flags);
 
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
 	return 0;
 }
 
-- 
2.14.1