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+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interconnect/samsung,exynos-bus.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos SoC Bus and Interconnect
+
+maintainers:
+ - Chanwoo Choi <cw00.choi@samsung.com>
+ - Krzysztof Kozlowski <krzk@kernel.org>
+
+description: |
+ 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.
+
+ 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 (Dynamic Memory Controller)
+
+ VDD_INT |--- LEFTBUS (parent device)
+ |--- PERIL
+ |--- MFC
+ |--- G3D
+ |--- RIGHTBUS
+ |--- PERIR
+ |--- 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 |
+ ----------------------------------------------------------
+
+ - In case of Exynos4210, there is one power line as following::
+ VDD_INT |--- DMC (parent device, Dynamic Memory Controller)
+ |--- 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 (Dynamic Memory Controller)
+
+ 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
+
+ - In case of Exynos5433, there is VDD_INT power line as following::
+ VDD_INT |--- G2D (parent device)
+ |--- MSCL
+ |--- GSCL
+ |--- JPEG
+ |--- MFC
+ |--- HEVC
+ |--- BUS0
+ |--- BUS1
+ |--- BUS2
+ |--- PERIS (Fixed clock rate)
+ |--- PERIC (Fixed clock rate)
+ |--- FSYS (Fixed clock rate)
+
+properties:
+ compatible:
+ enum:
+ - samsung,exynos-bus
+
+ clocks:
+ maxItems: 1
+
+ clock-names:
+ items:
+ - const: bus
+
+ devfreq:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description:
+ Parent bus device. Valid and required only for the passive bus devices.
+
+ devfreq-events:
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+ minItems: 1
+ maxItems: 4
+ description:
+ Devfreq-event device to monitor the current utilization of buses. Valid
+ and required only for the parent bus devices.
+
+ exynos,saturation-ratio:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description:
+ Percentage value which is used to calibrate the performance count against
+ total cycle count. Valid only for the parent bus devices.
+
+ '#interconnect-cells':
+ const: 0
+
+ interconnects:
+ minItems: 1
+ maxItems: 2
+
+ operating-points-v2: true
+ opp-table:
+ type: object
+
+ samsung,data-clock-ratio:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ default: 8
+ description:
+ Ratio of the data throughput in B/s to minimum data clock frequency in
+ Hz.
+
+ vdd-supply:
+ description:
+ Main bus power rail. Valid and required only for the parent bus devices.
+
+required:
+ - compatible
+ - clocks
+ - clock-names
+ - operating-points-v2
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/exynos3250.h>
+
+ bus-dmc {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu_dmc CLK_DIV_DMC>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_dmc_opp_table>;
+ devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+ vdd-supply = <&buck1_reg>;
+
+ bus_dmc_opp_table: opp-table {
+ compatible = "operating-points-v2";
+
+ 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>;
+ };
+ };
+ };
+
+ ppmu_dmc0: ppmu@106a0000 {
+ compatible = "samsung,exynos-ppmu";
+ reg = <0x106a0000 0x2000>;
+ events {
+ ppmu_dmc0_3: ppmu-event3-dmc0 {
+ event-name = "ppmu-event3-dmc0";
+ };
+ };
+ };
+
+ bus_leftbus: bus-leftbus {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_GDL>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
+ vdd-supply = <&buck3_reg>;
+ };
+
+ bus-rightbus {
+ compatible = "samsung,exynos-bus";
+ clocks = <&cmu CLK_DIV_GDR>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ devfreq = <&bus_leftbus>;
+ };
+
+ - |
+ dmc: bus-dmc {
+ compatible = "samsung,exynos-bus";
+ clocks = <&clock CLK_DIV_DMC>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_dmc_opp_table>;
+ samsung,data-clock-ratio = <4>;
+ #interconnect-cells = <0>;
+ devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+ vdd-supply = <&buck1_reg>;
+ };
+
+ leftbus: bus-leftbus {
+ compatible = "samsung,exynos-bus";
+ clocks = <&clock CLK_DIV_GDL>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_leftbus_opp_table>;
+ interconnects = <&dmc>;
+ #interconnect-cells = <0>;
+ devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
+ vdd-supply = <&buck3_reg>;
+ };
+
+ display: bus-display {
+ compatible = "samsung,exynos-bus";
+ clocks = <&clock CLK_DIV_ACLK_266>;
+ clock-names = "bus";
+ operating-points-v2 = <&bus_display_opp_table>;
+ interconnects = <&leftbus &dmc>;
+ #interconnect-cells = <0>;
+ devfreq = <&leftbus>;
+ };