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Diffstat (limited to 'Bindings/devfreq/exynos-bus.txt')
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diff --git a/Bindings/devfreq/exynos-bus.txt b/Bindings/devfreq/exynos-bus.txt new file mode 100644 index 000000000000..d3ec8e676b6b --- /dev/null +++ b/Bindings/devfreq/exynos-bus.txt @@ -0,0 +1,409 @@ +* 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"; + }; |