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SubjectRe: [PATCH v1 1/4] dt-bindings: memory: Add binding for MediaTek Common DRAM Controller
On Tue, Mar 30, 2021 at 01:22:08PM +0800, Po-Kai Chi wrote:
> This patch adds the documentation of the device-tree binding for
> MediaTek Common DRAM Controller.
>
> Signed-off-by: Po-Kai Chi <pk.chi@mediatek.com>
> ---
> .../memory-controllers/mediatek,dramc.yaml | 155 ++++++++++++++++++++
> 1 file changed, 155 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/memory-controllers/mediatek,dramc.yaml
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,dramc.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,dramc.yaml
> new file mode 100644
> index 0000000..0217ce0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,dramc.yaml
> @@ -0,0 +1,155 @@
> +# 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
> +
> + dram_type:

These need to be either common or have a vendor prefix.

Also, s/_/-/

> + 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
> +
> + support_channel_cnt:
> + description:
> + The maximum DRAM channel count supported by SoC.
> + $ref: /schemas/types.yaml#/definitions/uint32
> + minimum: 1
> + maximum: 4
> +
> + 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
> +
> + 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
> +
> + rank_size:
> + description:
> + 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
> + minItems: 1
> + maxItems: 2
> + items:
> + minimum: 0x0
> + maximum: 0x100000000 # support up to 4GB in single rank
> +
> + 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
> +
> + 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 mr_cnt
> + items:
> + items:
> + - description:
> + Mode register index
> + - description:
> + Mode register value
> +
> + freq_cnt:
> + description:
> + Specifies how many sets of DRAM data clock rate supported by SoC.
> + $ref: /schemas/types.yaml#/definitions/uint32
> +
> + 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

Looks like an OPP table.

> +
> +required:
> + - compatible
> + - reg
> + - dram_type
> + - support_channel_cnt
> + - channel_cnt
> + - rank_cnt
> + - mr_cnt
> + - freq_cnt
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + 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 */
> + dram_type = <0>;
> + support_channel_cnt = <2>;
> + channel_cnt = <2>;
> + rank_cnt = <2>;
> + rank_size = <0x40000000 0x40000000>;

You defined this as 64-bit, so this is a single value?

> + mr_cnt = <1>;
> + mr = <0x5 0xff>;
> + freq_cnt = <6>;
> + freq_step = <3718 3733>,
> + <3094 3200>,
> + <2392 2400>,
> + <1534 1600>,
> + <1196 1200>,
> + <754 800>;
> + };
> --
> 1.7.9.5
>

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