the driver uses the PPMU (Platform Performance Monitoring Unit), which
is able to measure the current load of sub-blocks.
+The Exynos SoC includes the various sub-blocks which have the each AXI bus.
+The each AXI bus has the owned source clock but, has not the only owned
+power line. The power line might be shared among one more sub-blocks.
+So, we can divide into two type of device as the role of each sub-block.
+There are two type of bus devices as following:
+- parent bus device
+- passive bus device
+
+Basically, parent and passive bus device share the same power line.
+The parent bus device can only change the voltage of shared power line
+and the rest bus devices (passive bus device) depend on the decision of
+the parent bus device. If there are three blocks which share the VDD_xxx
+power line, Only one block should be parent device and then the rest blocks
+should depend on the parent device as passive device.
+
+ VDD_xxx |--- A block (parent)
+ |--- B block (passive)
+ |--- C block (passive)
+
There are a little different composition among Exynos SoC because each Exynos
SoC has different sub-blocks. Therefore, such difference should be specified
in devicetree file instead of each device driver. In result, this driver
is able to support the bus frequency for all Exynos SoCs.
-Required properties for bus device:
+Required properties for all bus devices:
- compatible: Should be "samsung,exynos-bus".
- clock-names : the name of clock used by the bus, "bus".
- clocks : phandles for clock specified in "clock-names" property.
- operating-points-v2: the OPP table including frequency/voltage information
to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
+
+Required properties only for parent bus device:
- vdd-supply: the regulator to provide the buses with the voltage.
- devfreq-events: the devfreq-event device to monitor the current utilization
of buses.
-Optional properties for bus device:
+Required properties only for passive bus device:
+- devfreq: the parent bus device.
+
+Optional properties only for parent bus device:
- exynos,saturation-ratio: the percentage value which is used to calibrate
the performance count against total cycle count.
- exynos,voltage-tolerance: the percentage value for bus voltage tolerance
power line (regulator). The MIF (Memory Interface) AXI bus is used to
transfer data between DRAM and CPU and uses the VDD_MIF regulator.
- - power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block
+ - MIF (Memory Interface) block
+ : VDD_MIF |--- DMC (Dynamic Memory Controller)
+
+ - INT (Internal) block
+ : VDD_INT |--- LEFTBUS (parent device)
+ |--- PERIL
+ |--- MFC
+ |--- G3D
+ |--- RIGHTBUS
+ |--- FSYS
+ |--- LCD0
+ |--- PERIR
+ |--- ISP
+ |--- CAM
- MIF bus's frequency/voltage table
-----------------------
|L5| 400000 |875000 |
-----------------------
+ - INT bus's frequency/voltage table
+ ----------------------------------------------------------
+ |Block|LEFTBUS|RIGHTBUS|MCUISP |ISP |PERIL ||VDD_INT |
+ | name| |LCD0 | | | || |
+ | | |FSYS | | | || |
+ | | |MFC | | | || |
+ ----------------------------------------------------------
+ |Mode |*parent|passive |passive|passive|passive|| |
+ ----------------------------------------------------------
+ |Lv |Frequency ||Voltage |
+ ----------------------------------------------------------
+ |L1 |50000 |50000 |50000 |50000 |50000 ||900000 |
+ |L2 |80000 |80000 |80000 |80000 |80000 ||900000 |
+ |L3 |100000 |100000 |100000 |100000 |100000 ||1000000 |
+ |L4 |134000 |134000 |200000 |200000 | ||1000000 |
+ |L5 |200000 |200000 |400000 |300000 | ||1000000 |
+ ----------------------------------------------------------
+
Example2 :
The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
is listed below:
};
};
+ bus_leftbus: bus_leftbus {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_GDL>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ status = "disabled";
+ };
+
+ bus_rightbus: bus_rightbus {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_GDR>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ status = "disabled";
+ };
+
+ bus_lcd0: bus_lcd0 {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_ACLK_160>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ status = "disabled";
+ };
+
+ bus_fsys: bus_fsys {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_ACLK_200>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ status = "disabled";
+ };
+
+ bus_mcuisp: bus_mcuisp {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_ACLK_400_MCUISP>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_mcuisp_opp_table>;
+ status = "disabled";
+ };
+
+ bus_isp: bus_isp {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_ACLK_266>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_isp_opp_table>;
+ status = "disabled";
+ };
+
+ bus_peril: bus_peril {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_ACLK_100>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_peril_opp_table>;
+ status = "disabled";
+ };
+
+ bus_mfc: bus_mfc {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_SCLK_MFC>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ status = "disabled";
+ };
+
+ bus_leftbus_opp_table: opp_table1 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp@50000000 {
+ opp-hz = /bits/ 64 <50000000>;
+ opp-microvolt = <900000>;
+ };
+ opp@80000000 {
+ opp-hz = /bits/ 64 <80000000>;
+ opp-microvolt = <900000>;
+ };
+ opp@100000000 {
+ opp-hz = /bits/ 64 <100000000>;
+ opp-microvolt = <1000000>;
+ };
+ opp@134000000 {
+ opp-hz = /bits/ 64 <134000000>;
+ opp-microvolt = <1000000>;
+ };
+ opp@200000000 {
+ opp-hz = /bits/ 64 <200000000>;
+ opp-microvolt = <1000000>;
+ };
+ };
+
+ bus_mcuisp_opp_table: opp_table2 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp@50000000 {
+ opp-hz = /bits/ 64 <50000000>;
+ };
+ opp@80000000 {
+ opp-hz = /bits/ 64 <80000000>;
+ };
+ opp@100000000 {
+ opp-hz = /bits/ 64 <100000000>;
+ };
+ opp@200000000 {
+ opp-hz = /bits/ 64 <200000000>;
+ };
+ opp@400000000 {
+ opp-hz = /bits/ 64 <400000000>;
+ };
+ };
+
+ bus_isp_opp_table: opp_table3 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp@50000000 {
+ opp-hz = /bits/ 64 <50000000>;
+ };
+ opp@80000000 {
+ opp-hz = /bits/ 64 <80000000>;
+ };
+ opp@100000000 {
+ opp-hz = /bits/ 64 <100000000>;
+ };
+ opp@200000000 {
+ opp-hz = /bits/ 64 <200000000>;
+ };
+ opp@300000000 {
+ opp-hz = /bits/ 64 <300000000>;
+ };
+ };
+
+ bus_peril_opp_table: opp_table4 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp@50000000 {
+ opp-hz = /bits/ 64 <50000000>;
+ };
+ opp@80000000 {
+ opp-hz = /bits/ 64 <80000000>;
+ };
+ opp@100000000 {
+ opp-hz = /bits/ 64 <100000000>;
+ };
+ };
+
+
Usage case to handle the frequency and voltage of bus on runtime
in exynos3250-rinato.dts is listed below:
vdd-supply = <&buck1_reg>; /* VDD_MIF */
status = "okay";
};
+
+ &bus_leftbus {
+ devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
+ vdd-supply = <&buck3_reg>;
+ status = "okay";
+ };
+
+ &bus_rightbus {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
+
+ &bus_lcd0 {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
+
+ &bus_fsys {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
+
+ &bus_mcuisp {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
+
+ &bus_isp {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
+
+ &bus_peril {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
+
+ &bus_mfc {
+ devfreq = <&bus_leftbus>;
+ status = "okay";
+ };
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff