[PATCH v3 01/11] of: Add bindings of hw throttle for Tegra soctherm

Wei Ni
2016-05-03T10:16:34Z

Add HW throttle configuration sub-node for soctherm, which
is used to describe the throttle event, and worked as a
cooling device. The "hot" type trip in thermal zone can
be bound to this cooling device, and trigger the throttle
function.

Signed-off-by: Wei Ni <wni@nvidia.com>
---
.../bindings/thermal/nvidia,tegra124-soctherm.txt | 120 ++++++++++++++++++++-
1 file changed, 118 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/thermal/nvidia,tegra124-soctherm.txt b/Documentation/devicetree/bindings/thermal/nvidia,tegra124-soctherm.txt
index edebfa0a985e..6ba8ae3f59ed 100644
--- a/Documentation/devicetree/bindings/thermal/nvidia,tegra124-soctherm.txt
+++ b/Documentation/devicetree/bindings/thermal/nvidia,tegra124-soctherm.txt
@@ -10,8 +10,14 @@ Required properties :
- compatible : For Tegra124, must contain "nvidia,tegra124-soctherm".
For Tegra132, must contain "nvidia,tegra132-soctherm".
For Tegra210, must contain "nvidia,tegra210-soctherm".
-- reg : Should contain 1 entry:
+- reg : Should contain at least 2 entries for each entry in reg-names:
- SOCTHERM register set
+ - Tegra CAR register set: Required for Tegra124 and Tegra210.
+ - CCROC register set: Required for Tegra132.
+- reg-names : Should contain at least 2 entries:
+ - soctherm-reg
+ - car-reg
+ - ccroc-reg
- interrupts : Defines the interrupt used by SOCTHERM
- clocks : Must contain an entry for each entry in clock-names.
See ../clocks/clock-bindings.txt for details.
@@ -25,17 +31,44 @@ Required properties :
- #thermal-sensor-cells : Should be 1. See ./thermal.txt for a description
of this property. See <dt-bindings/thermal/tegra124-soctherm.h> for a
list of valid values when referring to thermal sensors.
+- nvidia,throttle-cfgs: A sub-node which is a container of configuration for
+ each hardware throttle events. These events can be set as cooling devices.
+ * throttle events: Sub-nodes must be named as "nvidia,light" or "nvidia,heavy".
+ Properties:
+ - nvidia,priority: Each throttles has its own throttle settings, so the
+ SW need to set priorities for various throttle, the HW arbiter can select
+ the final throttle settings.
+ Bigger value indicates higher priority, In general, higher priority
+ translates to lower target frequency. SW needs to ensure that critical
+ thermal alarms are given higher priority, and ensure that there is
+ no race if priority of two vectors is set to the same value.
+ - nvidia,cpu-throt-depth: This property is for Tegra124 and Tegra210.
+ It is the throttling depth of pulse skippers, it's the percentage
+ throttling.
+ - nvidia,cpu-throt-level: This property is only for Tegra132, it is the
+ level of pulse skippers, which used to throttle clock frequencies. It
+ indicates cpu clock throttling depth, and the depth can be programmed.
+ Must set as following values:
+ TEGRA_SOCTHERM_THROT_LEVEL_LOW, TEGRA_SOCTHERM_THROT_LEVEL_MED
+ TEGRA_SOCTHERM_THROT_LEVEL_HIGH, TEGRA_SOCTHERM_THROT_LEVEL_NONE
+ - #cooling-cells: Should be 1. This cooling device only support on/off state.
+ See ./thermal.txt for a description of this property.

Note:
- the "critical" type trip points will be set to SOC_THERM hardware as the
shut down temperature. Once the temperature of this thermal zone is higher
than it, the system will be shutdown or reset by hardware.
+- the "hot" type trip points will be set to SOC_THERM hardware as the throttle
+temperature. Once the the temperature of this thermal zone is higher
+than it, it will trigger the HW throttle event.

Example :

soctherm@700e2000 {
compatible = "nvidia,tegra124-soctherm";
- reg = <0x0 0x700e2000 0x0 0x1000>;
+ reg = <0x0 0x700e2000 0x0 0x600 /* SOC_THERM reg_base */
+ 0x0 0x60006000 0x0 0x400 /* CAR reg_base */
+ reg-names = "soctherm-reg", "car-reg";
interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&tegra_car TEGRA124_CLK_TSENSOR>,
<&tegra_car TEGRA124_CLK_SOC_THERM>;
@@ -44,6 +77,76 @@ Example :
reset-names = "soctherm";

#thermal-sensor-cells = <1>;
+
+ nvidia,throttle-cfgs {
+ /*
+ * When the "heavy" cooling device triggered,
+ * the HW will skip cpu clock's pulse in 85% depth
+ */
+ throttle_heavy: nvidia,heavy {
+ nvidia,priority = <100>;
+ nvidia,cpu-throt-depth = <85>;
+
+ #cooling-cells = <1>;
+ };
+
+ /*
+ * When the "light" cooling device triggered,
+ * the HW will skip cpu clock's pulse in 50% depth
+ */
+ throttle_light: nvidia,light {
+ nvidia,priority = <80>;
+ nvidia,cpu-throt-depth = <50>;
+
+ #cooling-cells = <1>;
+ };
+
+ /*
+ * If these two devices are triggered in same time, the HW throttle
+ * arbiter will select the highest priority as the final throttle
+ * settings to skip cpu pulse.
+ */
+ };
+ };
+
+Example: referring to Tegra132's "reg", "reg-names" and "throttle-cfgs" :
+
+ soctherm@0,700e2000 {
+ compatible = "nvidia,tegra132-soctherm";
+ reg = <0x0 0x700e2000 0x0 0x600 /* SOC_THERM reg_base */
+ 0x0 0x70040000 0x0 0x200>; /* CCROC reg_base */;
+ reg-names = "soctherm-reg", "ccroc-reg";
+
+ nvidia,throttle-cfgs {
+ /*
+ * When the "heavy" cooling device triggered,
+ * the HW will skip cpu clock's pulse in HIGH level
+ */
+ throttle_heavy: nvidia,heavy {
+ nvidia,priority = <100>;
+ nvidia,cpu-throt-level = <TEGRA_SOCTHERM_THROT_LEVEL_HIGH>;
+
+ #cooling-cells = <1>;
+ };
+
+ /*
+ * When the "light" cooling device triggered,
+ * the HW will skip cpu clock's pulse in MED level
+ */
+ throttle_light: nvidia,light {
+ nvidia,priority = <80>;
+ nvidia,cpu-throt-level = <TEGRA_SOCTHERM_THROT_LEVEL_MED>;
+
+ #cooling-cells = <1>;
+ };
+
+ /*
+ * If these two devices are triggered in same time, the HW throttle
+ * arbiter will select the highest priority as the final throttle
+ * settings to skip cpu pulse.
+ */
+
+ };
};

Example: referring to thermal sensors :
@@ -62,6 +165,19 @@ Example: referring to thermal sensors :
hysteresis = <1000>;
type = "critical";
};
+
+ cpu_throttle_trip: throttle-trip {
+ temperature = <100000>;
+ hysteresis = <1000>;
+ type = "hot";
+ };
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&cpu_throttle_trip>;
+ cooling-device = <&throttle_heavy 1 1>;
+ };
};
};
};
--
1.9.1