在 2016/8/19 21:36, Rob Herring 写道:
On Tue, Aug 16, 2016 at 10:38:59AM +0800, Finlye Xiao wrote:
From: Finley Xiao <[email protected]>
This patch supports adjusting opp's voltage according to leakage
Signed-off-by: Finley Xiao <[email protected]>
---
.../devicetree/bindings/power/rockchip-cpu-avs.txt | 37 +++
drivers/power/avs/Kconfig | 8 +
drivers/power/avs/Makefile | 1 +
drivers/power/avs/rockchip-cpu-avs.c | 314 +++++++++++++++++++++
4 files changed, 360 insertions(+)
create mode 100644
Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
create mode 100644 drivers/power/avs/rockchip-cpu-avs.c
diff --git a/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
b/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
new file mode 100644
index 0000000..90f6b08
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
@@ -0,0 +1,37 @@
+Rockchip cpu avs device tree bindings
+-------------------------------------
+
+Under the same frequency, the operating voltage tends to decrease with
+increasing leakage. so it is necessary to adjust opp's voltage according
+to leakage for power.
+
+
+Required properties:
+- compatible: Should be one of the following.
+ - "rockchip,rk3399-cpu-avs" - for RK3399 SoCs.
+- leakage-volt-<name>: Named leakage-volt property. At runtime, the
+ platform can find a cpu's cluster_id according to it's cpu_id and match
+ leakage-volt-<name> property. The property is an array of 3-tuples
+ items, and each item consists of leakage and voltage like
+ <min-leakage-mA max-leakage-mA vol-uV>.
+ min-leakage: minimum leakage in mA.
+ max-leakage: maximum leakage in mA.
+ vol: voltage in microvolt.
How do you determine these values? When do they vary?
How do you determine these values?
run antutu-benchmark
leakage freq min_volt
30mA 1608MHz 1025mV
40mA 1608MHz 1000mV
50mA 1608MHz 975mV
From the table, we see the min_volt decrease with increasing leakage.
So we can set the default opp-microvolt 1025mV for 1608MHz,
and add an leakage_volt_cluster0 property as follows.
leakage_volt_cluster0 = <
/* min(mA) max(mA) volt(uV)*/
0 40 0
41 50 (-25000)
51 254 (-50000)
;
If the leakage is between 41mA and 50mA，the opp-microvolt will subtract 25mV。
If the leakage is between 41mA and 50mA，the opp-microvolt will subtract 50mV。
When do they vary?
From the code,
cpufreq_online
--cpufreq_driver->init(policy); /* add new opp table */
--blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_START, policy);
--cpufreq_init_policy
----cpufreq_set_policy
--------__cpufreq_governor(policy, CPUFREQ_GOV_START);
The cpu's opp table is added in the init function(cpufreq_init)，and I will
register a cpufreq notifier, once the first cpu of cluster is onlined,
my notifer will be called, and if the event is CPUFREQ_START，it will modify
the opp-microvolt according to leakage_volt_cluster0.
+
+Example:
+
+ cpu_avs: cpu-avs {
+ compatible = "rockchip,rk3399-cpu-avs";
This isn't really a hardware block. For the same reasons we don't have
cpufreq nodes. So I don't think this belongs in DT.
if I delete the compatible property like the thermal-zones node, is it allowed?
cpu_avs: cpu-avs {
leakage_volt_cluster0 = <
/* min(mA) max(mA) volt(uV)*/
0 40 0
41 50 (-25000)
51 254 (-50000)
>;
leakage_volt_cluster1 = <
/* min(mA) max(mA) volt(uV)*/
0 40 0
41 50 (-25000)
51 254 (-50000)
>;
}
Rob
--
Finley
