From e753345bec8fef81d1e87710917f89dc75f39b2a Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Tue, 10 Jul 2012 11:13:16 -0700 Subject: [PATCH 1/3] ARM: OMAP: omap_device: keep track of driver bound status Use the bus notifier to keep track of driver bound status by adding a new internal field to struct omap_device: _driver_status. This will be useful for follow-up patches which need to know whether or not a driver is bound in order to make intelligent omap_device enable/idle decisions. Reviewed-by: Paul Walmsley Signed-off-by: Kevin Hilman --- arch/arm/plat-omap/include/plat/omap_device.h | 2 ++ arch/arm/plat-omap/omap_device.c | 14 +++++++++----- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h index 4327b2c90c3d..e7259c0d33ec 100644 --- a/arch/arm/plat-omap/include/plat/omap_device.h +++ b/arch/arm/plat-omap/include/plat/omap_device.h @@ -60,6 +60,7 @@ extern struct dev_pm_domain omap_device_pm_domain; * @_dev_wakeup_lat_limit: dev wakeup latency limit in nsec - set by OMAP PM * @_state: one of OMAP_DEVICE_STATE_* (see above) * @flags: device flags + * @_driver_status: one of BUS_NOTIFY_*_DRIVER from * * Integrates omap_hwmod data into Linux platform_device. * @@ -73,6 +74,7 @@ struct omap_device { struct omap_device_pm_latency *pm_lats; u32 dev_wakeup_lat; u32 _dev_wakeup_lat_limit; + unsigned long _driver_status; u8 pm_lats_cnt; s8 pm_lat_level; u8 hwmods_cnt; diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c index c490240bb82c..1d1b5ff78306 100644 --- a/arch/arm/plat-omap/omap_device.c +++ b/arch/arm/plat-omap/omap_device.c @@ -385,17 +385,21 @@ static int _omap_device_notifier_call(struct notifier_block *nb, unsigned long event, void *dev) { struct platform_device *pdev = to_platform_device(dev); + struct omap_device *od; switch (event) { - case BUS_NOTIFY_ADD_DEVICE: - if (pdev->dev.of_node) - omap_device_build_from_dt(pdev); - break; - case BUS_NOTIFY_DEL_DEVICE: if (pdev->archdata.od) omap_device_delete(pdev->archdata.od); break; + case BUS_NOTIFY_ADD_DEVICE: + if (pdev->dev.of_node) + omap_device_build_from_dt(pdev); + /* fall through */ + default: + od = to_omap_device(pdev); + if (od) + od->_driver_status = event; } return NOTIFY_DONE; From 72bb6f9b51c82c820ddef892455a85b115460904 Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Tue, 10 Jul 2012 15:29:04 -0700 Subject: [PATCH 2/3] ARM: OMAP: omap_device: don't attempt late suspend if no driver bound Currently, the omap_device PM domain layer uses the late suspend and early resume callbacks to ensure devices are in their low power states. However, this is attempted even in cases where a driver probe has failed. If a driver's ->probe() method fails, the driver is likely in a state where it is not expecting its runtime PM callbacks to be called, yet currently the omap_device PM domain code attempts to call the drivers callbacks. To fix, use the omap_device driver_status field to check whether a driver is bound to the omap_device before attempting to trigger driver callbacks. Reviewed-by: Paul Walmsley Signed-off-by: Kevin Hilman --- arch/arm/plat-omap/omap_device.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c index 1d1b5ff78306..150112e3ffc8 100644 --- a/arch/arm/plat-omap/omap_device.c +++ b/arch/arm/plat-omap/omap_device.c @@ -756,6 +756,10 @@ static int _od_suspend_noirq(struct device *dev) struct omap_device *od = to_omap_device(pdev); int ret; + /* Don't attempt late suspend on a driver that is not bound */ + if (od->_driver_status != BUS_NOTIFY_BOUND_DRIVER) + return 0; + ret = pm_generic_suspend_noirq(dev); if (!ret && !pm_runtime_status_suspended(dev)) { From 9634c8dd6a729406e89aed4e29470e3ffb3cd060 Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Tue, 10 Jul 2012 15:06:11 -0700 Subject: [PATCH 3/3] ARM: OMAP: omap_device: idle devices with no driver bound Under some circumstances, drivers may leave an omap_device enabled due to driver programming errors, or due to a failure in the drivers probe method. Using the recently added omap_device driver_status field, we can detect conditions where an omap_device is enabled but has no driver bound and then ensure that the device is properly idled until it can be probed again. The goal of this feature is not only to detect and warn on these error conditions, but also to ensure that devices are properly put in low-power states so they do not prevent SoC-wide low-power states. Reviewed-by: Paul Walmsley Signed-off-by: Kevin Hilman --- arch/arm/plat-omap/omap_device.c | 38 ++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c index 150112e3ffc8..0f519829e795 100644 --- a/arch/arm/plat-omap/omap_device.c +++ b/arch/arm/plat-omap/omap_device.c @@ -1133,3 +1133,41 @@ static int __init omap_device_init(void) return 0; } core_initcall(omap_device_init); + +/** + * omap_device_late_idle - idle devices without drivers + * @dev: struct device * associated with omap_device + * @data: unused + * + * Check the driver bound status of this device, and idle it + * if there is no driver attached. + */ +static int __init omap_device_late_idle(struct device *dev, void *data) +{ + struct platform_device *pdev = to_platform_device(dev); + struct omap_device *od = to_omap_device(pdev); + + if (!od) + return 0; + + /* + * If omap_device state is enabled, but has no driver bound, + * idle it. + */ + if (od->_driver_status != BUS_NOTIFY_BOUND_DRIVER) { + if (od->_state == OMAP_DEVICE_STATE_ENABLED) { + dev_warn(dev, "%s: enabled but no driver. Idling\n", + __func__); + omap_device_idle(pdev); + } + } + + return 0; +} + +static int __init omap_device_late_init(void) +{ + bus_for_each_dev(&platform_bus_type, NULL, NULL, omap_device_late_idle); + return 0; +} +late_initcall(omap_device_late_init);