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authorSascha Hauer <s.hauer@pengutronix.de>2016-06-13 07:31:46 +0200
committerSascha Hauer <s.hauer@pengutronix.de>2016-06-13 12:43:53 +0200
commit86186c232241b607f84cc266a6cda49160f44948 (patch)
tree286a87dae7f2d8c3eda5b8551fc9b5f4db726c45 /dts/Bindings/devfreq/exynos-bus.txt
parent0cf29e11efa66ad4515c9391303406c725be2c7a (diff)
downloadbarebox-86186c232241b607f84cc266a6cda49160f44948.tar.gz
barebox-86186c232241b607f84cc266a6cda49160f44948.tar.xz
dts: update to v4.7-rc1
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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+* Generic Exynos Bus frequency device
+
+The Samsung Exynos SoC has many buses for data transfer between DRAM
+and sub-blocks in SoC. Most Exynos SoCs share the common architecture
+for buses. Generally, each bus of Exynos SoC includes a source clock
+and a power line, which are able to change the clock frequency
+of the bus in runtime. To monitor the usage of each bus in runtime,
+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 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.
+
+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
+ which is used to calculate the max voltage.
+
+Detailed correlation between sub-blocks and power line according to Exynos SoC:
+- In case of Exynos3250, there are two power line as following:
+ VDD_MIF |--- DMC
+
+ VDD_INT |--- LEFTBUS (parent device)
+ |--- PERIL
+ |--- MFC
+ |--- G3D
+ |--- RIGHTBUS
+ |--- PERIR
+ |--- FSYS
+ |--- LCD0
+ |--- PERIR
+ |--- ISP
+ |--- CAM
+
+- In case of Exynos4210, there is one power line as following:
+ VDD_INT |--- DMC (parent device)
+ |--- LEFTBUS
+ |--- PERIL
+ |--- MFC(L)
+ |--- G3D
+ |--- TV
+ |--- LCD0
+ |--- RIGHTBUS
+ |--- PERIR
+ |--- MFC(R)
+ |--- CAM
+ |--- FSYS
+ |--- GPS
+ |--- LCD0
+ |--- LCD1
+
+- In case of Exynos4x12, there are two power line as following:
+ VDD_MIF |--- DMC
+
+ VDD_INT |--- LEFTBUS (parent device)
+ |--- PERIL
+ |--- MFC(L)
+ |--- G3D
+ |--- TV
+ |--- IMAGE
+ |--- RIGHTBUS
+ |--- PERIR
+ |--- MFC(R)
+ |--- CAM
+ |--- FSYS
+ |--- GPS
+ |--- LCD0
+ |--- ISP
+
+- In case of Exynos5422, there are two power line as following:
+ VDD_MIF |--- DREX 0 (parent device, DRAM EXpress controller)
+ |--- DREX 1
+
+ VDD_INT |--- NoC_Core (parent device)
+ |--- G2D
+ |--- G3D
+ |--- DISP1
+ |--- NoC_WCORE
+ |--- GSCL
+ |--- MSCL
+ |--- ISP
+ |--- MFC
+ |--- GEN
+ |--- PERIS
+ |--- PERIC
+ |--- FSYS
+ |--- FSYS2
+
+Example1:
+ Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to
+ power line (regulator). The MIF (Memory Interface) AXI bus is used to
+ transfer data between DRAM and CPU and uses the VDD_MIF regulator.
+
+ - 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
+ -----------------------
+ |Lv| Freq | Voltage |
+ -----------------------
+ |L1| 50000 |800000 |
+ |L2| 100000 |800000 |
+ |L3| 134000 |800000 |
+ |L4| 200000 |825000 |
+ |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_dmc: bus_dmc {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu_dmc CLK_DIV_DMC>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_dmc_opp_table>;
+ status = "disabled";
+ };
+
+ bus_dmc_opp_table: opp_table1 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp@50000000 {
+ opp-hz = /bits/ 64 <50000000>;
+ opp-microvolt = <800000>;
+ };
+ opp@100000000 {
+ opp-hz = /bits/ 64 <100000000>;
+ opp-microvolt = <800000>;
+ };
+ opp@134000000 {
+ opp-hz = /bits/ 64 <134000000>;
+ opp-microvolt = <800000>;
+ };
+ opp@200000000 {
+ opp-hz = /bits/ 64 <200000000>;
+ opp-microvolt = <825000>;
+ };
+ opp@400000000 {
+ opp-hz = /bits/ 64 <400000000>;
+ opp-microvolt = <875000>;
+ };
+ };
+
+ 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:
+
+ &bus_dmc {
+ devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+ 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";
+ };