On 2016?05?26? 08:34, Caesar Wang wrote: > > On 2016?05?26? 00:42, Javi Merino wrote: >> Hi Caesar, >> >> On Wed, May 25, 2016 at 11:47:45AM +0800, Caesar Wang wrote: >>> From: Sascha Hauer <s.hauer at pengutronix.de> >>> >>> This adds support for hardware-tracked trip points to the device tree >>> thermal sensor framework. >>> >>> The framework supports an arbitrary number of trip points. Whenever >>> the current temperature is updated, the trip points immediately >>> below and above the current temperature are found. A .set_trips >>> callback is then called with the temperatures. If there is no trip >>> point above or below the current temperature, the passed trip >>> temperature will be -INT_MAX or INT_MAX respectively. In this callback, >>> the driver should program the hardware such that it is notified >>> when either of these trip points are triggered. When a trip point >>> is triggered, the driver should call `thermal_zone_device_update' >>> for the respective thermal zone. This will cause the trip points >>> to be updated again. >>> >>> If .set_trips is not implemented, the framework behaves as before. >>> >>> This patch is based on an earlier version from Mikko Perttunen >>> <mikko.perttunen at kapsi.fi> >>> >>> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de> >>> Signed-off-by: Caesar Wang <wxt at rock-chips.com> >>> Cc: Zhang Rui <rui.zhang at intel.com> >>> Cc: Eduardo Valentin <edubezval at gmail.com> >>> Cc: linux-pm at vger.kernel.org >>> >>> --- >>> >>> Changes in v3: >>> - as Javi comments on https://patchwork.kernel.org/patch/9001281/. >>> - add the lock for preventing the called from multi placce >>> - add the note for pre_low/high_trip. >>> >>> Changes in v2: >>> - update the sysfs-api.txt for set_trips. >>> >>> Documentation/thermal/sysfs-api.txt | 7 +++++ >>> drivers/thermal/thermal_core.c | 52 >>> +++++++++++++++++++++++++++++++++++++ >>> include/linux/thermal.h | 7 +++++ >>> 3 files changed, 66 insertions(+) >>> >>> diff --git a/Documentation/thermal/sysfs-api.txt >>> b/Documentation/thermal/sysfs-api.txt >>> index efc3f3d..75d8838 100644 >>> --- a/Documentation/thermal/sysfs-api.txt >>> +++ b/Documentation/thermal/sysfs-api.txt >>> @@ -49,6 +49,9 @@ temperature) and throttle appropriate devices. >>> .bind: bind the thermal zone device with a thermal cooling >>> device. >>> .unbind: unbind the thermal zone device with a thermal cooling >>> device. >>> .get_temp: get the current temperature of the thermal zone. >>> + .set_trips: set the trip points window. Whenever the current >>> temperature >>> + is updated, the trip points immediately below and above >>> the >>> + current temperature are found. >>> .get_mode: get the current mode (enabled/disabled) of the >>> thermal zone. >>> - "enabled" means the kernel thermal management is enabled. >>> - "disabled" will prevent kernel thermal driver action >>> upon trip points >>> @@ -95,6 +98,10 @@ temperature) and throttle appropriate devices. >>> get_temp: a pointer to a function that reads the >>> sensor temperature. This is mandatory >>> callback provided by sensor driver. >>> + set_trips: a pointer to a function that sets a >>> + temperature window. When this window is >>> + left the driver must inform the thermal >>> + core via thermal_zone_device_update. >>> get_trend: a pointer to a function that reads the >>> sensor temperature trend. >>> set_emul_temp: a pointer to a function that sets >>> diff --git a/drivers/thermal/thermal_core.c >>> b/drivers/thermal/thermal_core.c >>> index 5133cd1..e5bfbd3 100644 >>> --- a/drivers/thermal/thermal_core.c >>> +++ b/drivers/thermal/thermal_core.c >>> @@ -520,6 +520,51 @@ exit: >>> } >>> EXPORT_SYMBOL_GPL(thermal_zone_get_temp); >>> +static void thermal_zone_set_trips(struct thermal_zone_device *tz) >>> +{ >>> + int low = -INT_MAX; >>> + int high = INT_MAX; >>> + int trip_temp, hysteresis; >>> + int temp = tz->temperature; >>> + int i, ret; >>> + >>> + if (!tz->ops->set_trips) >>> + return; >>> + >>> + for (i = 0; i < tz->trips; i++) { >>> + int trip_low; >>> + >>> + tz->ops->get_trip_temp(tz, i, &trip_temp); >>> + tz->ops->get_trip_hyst(tz, i, &hysteresis); >>> + >>> + trip_low = trip_temp - hysteresis; >>> + >>> + if (trip_low < temp && trip_low > low) >>> + low = trip_low; >>> + >>> + if (trip_temp > temp && trip_temp < high) >>> + high = trip_temp; >>> + } >>> + >>> + /* No need to change trip points */ >>> + if (tz->prev_low_trip == low && tz->prev_high_trip == high) >>> + return; >>> + >>> + tz->prev_low_trip = low; >>> + tz->prev_high_trip = high; >>> + >>> + dev_dbg(&tz->device, "new temperature boundaries: %d < x < %d\n", >>> + low, high); >>> + >>> + /* >>> + * Set a temperature window. When this window is left the driver >>> + * must inform the thermal core via thermal_zone_device_update. >>> + */ >>> + ret = tz->ops->set_trips(tz, low, high); >>> + if (ret) >>> + dev_err(&tz->device, "Failed to set trips: %d\n", ret); >> In the v2 review >> (http://article.gmane.org/gmane.linux.documentation/38442) you agreed >> to add locking but you haven't done it. Maybe you sent the wrong >> version? > > My god! > Yep, I remember to change it. Somehow why ... > > Thanks Javi for looking over it. > > Hoping the next version is the final version.:-) > If add the lock, there is a deadlock for board, maybe I will keep to stay with this version. 2.895038] [ INFO: possible recursive locking detected ] [ 2.900459] 4.4.4 #56 Not tainted [ 2.903774] --------------------------------------------- [ 2.909171] swapper/0/1 is trying to acquire lock: [ 2.913974] (&tz->lock){+.+.+.}, at: [<ffffffc00069b428>] handle_thermal_trip+0x230/0x304 [ 2.922336] [ 2.922336] but task is already holding lock: [ 2.928166] (&tz->lock){+.+.+.}, at: [<ffffffc000699194>] thermal_zone_set_trips+0xd8/0x180 [ 2.936670] [ 2.936670] other info that might help us debug this: [ 2.943199] Possible unsafe locking scenario: [ 2.943199] [ 2.949117] CPU0 [ 2.951565] ---- [ 2.954012] lock(&tz->lock); [ 2.957098] lock(&tz->lock); [ 2.960176] [ 2.960176] *** DEADLOCK *** [ 2.960176] [ 2.966098] May be due to missing lock nesting notation [ 2.966098] [ 2.972885] 3 locks held by swapper/0/1: [ 2.976809] #0: (&dev->mutex){......}, at: [<ffffffc0005920b0>] __driver_attach+0x40/0xa8 [ 2.985243] #1: (&dev->mutex){......}, at: [<ffffffc0005920d8>] __driver_attach+0x68/0xa8 [ 2.993671] #2: (&tz->lock){+.+.+.}, at: [<ffffffc000699194>] thermal_zone_set_trips+0xd8/0x180 ... > -Caesar > >> >> Cheers, >> Javi >> >> _______________________________________________ >> Linux-rockchip mailing list >> Linux-rockchip at lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-rockchip > > -- caesar wang | software engineer | wxt at rock-chip.com
