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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (c) 2021 MediaTek Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/mediatek,dramc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek DRAM Controller
+
+maintainers:
+ - Po-Kai Chi <pk.chi@mediatek.com>
+
+description: |
+ MediaTek DRAM controller (DRAMC) provides an interface to query information
+ about DRAM which collected from bootloader and device tree.
+ This is mainly used by MediaTek Extended Memory Interface (EMI) and DVFS Resource
+ Control (DVFSRC).
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - mediatek,mt6779-dramc
+
+ reg:
+ description:
+ Base address of MediaTek DRAM related hardware modules, each channel has
+ its own base address in order of
+ DRAMC_AO_{CH}, DRAMC_NAO_{CH}, DDRPHY_AO_{CH}.
+ minItems: 3 # 3 * N channels
+ maxItems: 6
+
+ mediatek,dram-type:
+ description:
+ The DRAM type of current DRAM chip.
+ This property is filled in by bootloader according to the board hardware
+ configuration.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 0
+ maximum: 7
+
+ mediatek,support-channel-cnt:
+ description:
+ The maximum DRAM channel count supported by SoC.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 4
+
+ mediatek,channel-cnt:
+ description:
+ The DRAM channel count of current DRAM chip.
+ This property is filled in by bootloader according to the board hardware
+ configuration.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 4
+
+ mediatek,rank-cnt:
+ description:
+ The DRAM rank count of current DRAM chip.
+ This property is filled in by bootloader according to the board hardware
+ configuration.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 2
+
+ mediatek,rank-size:
+ description:
+ An array of 64-bits unsigned integer that describes the size of each
+ DRAM rank.
+ This property is filled in by bootloader according to the board hardware
+ configuration.
+ $ref: /schemas/types.yaml#/definitions/uint64-array
+ minItems: 1
+ maxItems: 2
+ items:
+ minimum: 0x0
+ maximum: 0x100000000 # support up to 4GB in single rank
+
+ mediatek,mr-cnt:
+ description:
+ Specifies how many sets of DRAM mode register information to provide.
+ This property is filled in by bootloader according to the board hardware
+ configuration.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maximum: 40 # total 40 MRs for JEDEC LPDDR4X
+
+ mediatek,mr:
+ description:
+ Pair of DRAM mode register information.
+ This property is filled in by bootloader according to the board hardware
+ configuration.
+ $ref: /schemas/types.yaml#/definitions/uint32-matrix
+ maxItems: 40 # align with mediatek,mr-cnt
+ items:
+ items:
+ - description:
+ Mode register index
+ - description:
+ Mode register value
+
+ mediatek,freq-cnt:
+ description:
+ Specifies how many sets of DRAM data clock rate supported by SoC.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ mediatek,freq-step:
+ description:
+ The DRAM data clock rate may be slightly different from those defined
+ by the specification due to errors in multiples of the base frequency.
+ This describe the mapping from real data clock rate measured by
+ frequency meter to JEDEC data clock rate.
+ $ref: /schemas/types.yaml#/definitions/uint32-matrix
+ items:
+ items:
+ - description:
+ Real data rate
+ - description:
+ Spec data rate
+
+required:
+ - compatible
+ - reg
+ - mediatek,dram-type
+ - mediatek,support-channel-cnt
+ - mediatek,channel-cnt
+ - mediatek,rank-cnt
+ - mediatek,mr-cnt
+ - mediatek,freq-cnt
+
+additionalProperties: false
+
+examples:
+ - |
+ soc {
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ dramc@10230000 {
+ compatible = "mediatek,mt6779-dramc";
+ reg = <0 0x10230000 0 0x2000>, /* DRAMC AO CHA */
+ <0 0x10240000 0 0x2000>, /* DRAMC AO CHB */
+ <0 0x10234000 0 0x1000>, /* DRAMC NAO CHA */
+ <0 0x10244000 0 0x1000>, /* DRAMC NAO CHB */
+ <0 0x10238000 0 0x2000>, /* DDRPHY AO CHA */
+ <0 0x10248000 0 0x2000>; /* DDRPHY AO CHB */
+ mediatek,dram-type = <0>;
+ mediatek,support-channel-cnt = <2>;
+ mediatek,channel-cnt = <2>;
+ mediatek,rank-cnt = <2>;
+ mediatek,rank-size = <0x40000000 0x40000000>;
+ mediatek,mr-cnt = <1>;
+ mediatek,mr = <0x5 0xff>;
+ mediatek,freq-cnt = <6>;
+ mediatek,freq-step = <3718 3733>,
+ <3094 3200>,
+ <2392 2400>,
+ <1534 1600>,
+ <1196 1200>,
+ <754 800>;
+ };
+ };
This patch adds the documentation of the device-tree binding for MediaTek DRAM Controller. Signed-off-by: Po-Kai Chi <pk.chi@mediatek.com> --- .../memory-controllers/mediatek,dramc.yaml | 162 ++++++++++++++++++++ 1 file changed, 162 insertions(+) create mode 100644 Documentation/devicetree/bindings/memory-controllers/mediatek,dramc.yaml