linux-kernel - [PATCH 4.9 147/172] ARM: OMAP2+: omap_device: Sync omap_device and pm

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Date:   Mon,  3 Jul 2017 15:35:27 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, "Franklin S Cooper Jr." <fcooper@...com>,
        Dave Gerlach <d-gerlach@...com>,
        Tony Lindgren <tony@...mide.com>
Subject: [PATCH 4.9 147/172] ARM: OMAP2+: omap_device: Sync omap_device and pm_runtime after probe defer

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Gerlach <d-gerlach@...com>

commit 04abaf07f6d5cdf22b7a478a86e706dfeeeef960 upstream.

Starting from commit 5de85b9d57ab ("PM / runtime: Re-init runtime PM
states at probe error and driver unbind") pm_runtime core now changes
device runtime_status back to after RPM_SUSPENDED after a probe defer.
Certain OMAP devices make use of "ti,no-idle-on-init" flag which causes
omap_device_enable to be called during the BUS_NOTIFY_ADD_DEVICE event
during probe, along with pm_runtime_set_active.

This call to pm_runtime_set_active typically will prevent a call to
pm_runtime_get in a driver probe function from re-enabling the
omap_device. However, in the case of a probe defer that happens before
the driver probe function is able to run, such as a missing pinctrl
states defer, pm_runtime_reinit will set the device as RPM_SUSPENDED and
then once driver probe is actually able to run, pm_runtime_get will see
the device as suspended and call through to the omap_device layer,
attempting to enable the already enabled omap_device and causing errors
like this:

omap-gpmc 50000000.gpmc: omap_device: omap_device_enable() called from
invalid state 1
omap-gpmc 50000000.gpmc: use pm_runtime_put_sync_suspend() in driver?

We can avoid this error by making sure the pm_runtime status of a device
matches the omap_device state before a probe attempt. By extending the
omap_device bus notifier to act on the BUS_NOTIFY_BIND_DRIVER event we
can check if a device is enabled in omap_device but with a pm_runtime
status of RPM_SUSPENDED and once again mark the device as RPM_ACTIVE to
avoid a second incorrect call to omap_device_enable.

Fixes: 5de85b9d57ab ("PM / runtime: Re-init runtime PM states at probe
error and driver unbind")
Tested-by: Franklin S Cooper Jr. <fcooper@...com>
Signed-off-by: Dave Gerlach <d-gerlach@...com>
Signed-off-by: Tony Lindgren <tony@...mide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm/mach-omap2/omap_device.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -222,6 +222,14 @@ static int _omap_device_notifier_call(st
 				dev_err(dev, "failed to idle\n");
 		}
 		break;
+	case BUS_NOTIFY_BIND_DRIVER:
+		od = to_omap_device(pdev);
+		if (od && (od->_state == OMAP_DEVICE_STATE_ENABLED) &&
+		    pm_runtime_status_suspended(dev)) {
+			od->_driver_status = BUS_NOTIFY_BIND_DRIVER;
+			pm_runtime_set_active(dev);
+		}
+		break;
 	case BUS_NOTIFY_ADD_DEVICE:
 		if (pdev->dev.of_node)
 			omap_device_build_from_dt(pdev);