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SubjectRe: [PATCH v1 5/6] dt-bindings: memory: tegra20: emc: Convert to schema
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On 29/03/2021 21:46, Dmitry Osipenko wrote:
> Convert Tegra20 External Memory Controller binding to schema.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> .../memory-controllers/nvidia,tegra20-emc.txt | 130 --------
> .../nvidia,tegra20-emc.yaml | 294 ++++++++++++++++++
> 2 files changed, 294 insertions(+), 130 deletions(-)
> delete mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> create mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> deleted file mode 100644
> index d2250498c36d..000000000000
> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> +++ /dev/null
> @@ -1,130 +0,0 @@
> -Embedded Memory Controller
> -
> -Properties:
> -- name : Should be emc
> -- #address-cells : Should be 1
> -- #size-cells : Should be 0
> -- compatible : Should contain "nvidia,tegra20-emc".
> -- reg : Offset and length of the register set for the device
> -- nvidia,use-ram-code : If present, the sub-nodes will be addressed
> - and chosen using the ramcode board selector. If omitted, only one
> - set of tables can be present and said tables will be used
> - irrespective of ram-code configuration.
> -- interrupts : Should contain EMC General interrupt.
> -- clocks : Should contain EMC clock.
> -- nvidia,memory-controller : Phandle of the Memory Controller node.
> -- #interconnect-cells : Should be 0.
> -- operating-points-v2: See ../bindings/opp/opp.txt for details.
> -
> -For each opp entry in 'operating-points-v2' table:
> -- opp-supported-hw: One bitfield indicating SoC process ID mask
> -
> - A bitwise AND is performed against this value and if any bit
> - matches, the OPP gets enabled.
> -
> -Optional properties:
> -- power-domains: Phandle of the SoC "core" power domain.
> -
> -Child device nodes describe the memory settings for different configurations and clock rates.
> -
> -Example:
> -
> - opp_table: opp-table {
> - compatible = "operating-points-v2";
> -
> - opp@36000000 {
> - opp-microvolt = <950000 950000 1300000>;
> - opp-hz = /bits/ 64 <36000000>;
> - };
> - ...
> - };
> -
> - memory-controller@7000f400 {
> - #address-cells = < 1 >;
> - #size-cells = < 0 >;
> - #interconnect-cells = <0>;
> - compatible = "nvidia,tegra20-emc";
> - reg = <0x7000f400 0x400>;
> - interrupts = <0 78 0x04>;
> - clocks = <&tegra_car TEGRA20_CLK_EMC>;
> - nvidia,memory-controller = <&mc>;
> - power-domains = <&domain>;
> - operating-points-v2 = <&opp_table>;
> - }
> -
> -
> -Embedded Memory Controller ram-code table
> -
> -If the emc node has the nvidia,use-ram-code property present, then the
> -next level of nodes below the emc table are used to specify which settings
> -apply for which ram-code settings.
> -
> -If the emc node lacks the nvidia,use-ram-code property, this level is omitted
> -and the tables are stored directly under the emc node (see below).
> -
> -Properties:
> -
> -- name : Should be emc-tables
> -- nvidia,ram-code : the binary representation of the ram-code board strappings
> - for which this node (and children) are valid.
> -
> -
> -
> -Embedded Memory Controller configuration table
> -
> -This is a table containing the EMC register settings for the various
> -operating speeds of the memory controller. They are always located as
> -subnodes of the emc controller node.
> -
> -There are two ways of specifying which tables to use:
> -
> -* The simplest is if there is just one set of tables in the device tree,
> - and they will always be used (based on which frequency is used).
> - This is the preferred method, especially when firmware can fill in
> - this information based on the specific system information and just
> - pass it on to the kernel.
> -
> -* The slightly more complex one is when more than one memory configuration
> - might exist on the system. The Tegra20 platform handles this during
> - early boot by selecting one out of possible 4 memory settings based
> - on a 2-pin "ram code" bootstrap setting on the board. The values of
> - these strappings can be read through a register in the SoC, and thus
> - used to select which tables to use.
> -
> -Properties:
> -- name : Should be emc-table
> -- compatible : Should contain "nvidia,tegra20-emc-table".
> -- reg : either an opaque enumerator to tell different tables apart, or
> - the valid frequency for which the table should be used (in kHz).
> -- clock-frequency : the clock frequency for the EMC at which this
> - table should be used (in kHz).
> -- nvidia,emc-registers : a 46 word array of EMC registers to be programmed
> - for operation at the 'clock-frequency' setting.
> - The order and contents of the registers are:
> - RC, RFC, RAS, RP, R2W, W2R, R2P, W2P, RD_RCD, WR_RCD, RRD, REXT,
> - WDV, QUSE, QRST, QSAFE, RDV, REFRESH, BURST_REFRESH_NUM, PDEX2WR,
> - PDEX2RD, PCHG2PDEN, ACT2PDEN, AR2PDEN, RW2PDEN, TXSR, TCKE, TFAW,
> - TRPAB, TCLKSTABLE, TCLKSTOP, TREFBW, QUSE_EXTRA, FBIO_CFG6, ODT_WRITE,
> - ODT_READ, FBIO_CFG5, CFG_DIG_DLL, DLL_XFORM_DQS, DLL_XFORM_QUSE,
> - ZCAL_REF_CNT, ZCAL_WAIT_CNT, AUTO_CAL_INTERVAL, CFG_CLKTRIM_0,
> - CFG_CLKTRIM_1, CFG_CLKTRIM_2
> -
> - emc-table@166000 {
> - reg = <166000>;
> - compatible = "nvidia,tegra20-emc-table";
> - clock-frequency = < 166000 >;
> - nvidia,emc-registers = < 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> - 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> - 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> - 0 0 0 0 >;
> - };
> -
> - emc-table@333000 {
> - reg = <333000>;
> - compatible = "nvidia,tegra20-emc-table";
> - clock-frequency = < 333000 >;
> - nvidia,emc-registers = < 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> - 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> - 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> - 0 0 0 0 >;
> - };
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
> new file mode 100644
> index 000000000000..9665fdd80b22
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
> @@ -0,0 +1,294 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/memory-controllers/nvidia,tegra20-emc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NVIDIA Tegra20 SoC External Memory Controller
> +
> +maintainers:
> + - Dmitry Osipenko <digetx@gmail.com>
> + - Jon Hunter <jonathanh@nvidia.com>
> + - Thierry Reding <thierry.reding@gmail.com>
> +
> +description: |
> + The External Memory Controller (EMC) interfaces with the off-chip SDRAM to
> + service the request stream sent from Memory Controller. The EMC also has
> + various performance-affecting settings beyond the obvious SDRAM configuration
> + parameters and initialization settings. Tegra20 EMC supports multiple JEDEC
> + standard protocols: DDR1, LPDDR2 and DDR2.
> +
> +properties:
> + compatible:
> + const: nvidia,tegra20-emc
> +
> + reg:
> + maxItems: 1
> +
> + clocks:
> + maxItems: 1

An idea for a follow-up patch (not needed here) - add the clock-names
and get the clock by name in the driver.

> +
> + interrupts:
> + maxItems: 1
> +
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + "#interconnect-cells":
> + const: 0
> +
> + nvidia,memory-controller:
> + $ref: /schemas/types.yaml#/definitions/phandle
> + description:
> + Phandle of the Memory Controller node.
> +
> + power-domains:
> + $ref: /schemas/types.yaml#/definitions/phandle
> + description:
> + Phandle of the SoC "core" power domain.

I think the core checks the type, so you only need to limit max items.

> +
> + operating-points-v2:
> + description:
> + Should contain freqs and voltages and opp-supported-hw property, which
> + is a bitfield indicating SoC process ID mask.
> +
> + nvidia,use-ram-code:
> + type: boolean
> + description:
> + If present, the emc-tables@ sub-nodes will be addressed.
> +
> +patternProperties:
> + "^emc-table@[0-9]+$":

This might not be easy but you should add constraints when emc-table and
emc-tables are expected. The schema should check if proper node is used
depending on "nvidia,use-ram-code".

> + type: object
> + properties:
> + compatible:
> + const: nvidia,tegra20-emc-table
> +
> + clock-frequency:
> + description:
> + Memory clock rate in kHz.
> + minimum: 1000
> + maximum: 900000
> +
> + reg:
> + maxItems: 1
> + description:
> + Either an opaque enumerator to tell different tables apart, or
> + the valid frequency for which the table should be used (in kHz).
> +
> + nvidia,emc-registers:
> + description:
> + EMC timing characterization data. These are the registers
> + (see section "15.4.1 EMC Registers" in the TRM) whose values
> + need to be specified, according to the board documentation.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + items:
> + - description: EMC_RC
> + - description: EMC_RFC
> + - description: EMC_RAS
> + - description: EMC_RP
> + - description: EMC_R2W
> + - description: EMC_W2R
> + - description: EMC_R2P
> + - description: EMC_W2P
> + - description: EMC_RD_RCD
> + - description: EMC_WR_RCD
> + - description: EMC_RRD
> + - description: EMC_REXT
> + - description: EMC_WDV
> + - description: EMC_QUSE
> + - description: EMC_QRST
> + - description: EMC_QSAFE
> + - description: EMC_RDV
> + - description: EMC_REFRESH
> + - description: EMC_BURST_REFRESH_NUM
> + - description: EMC_PDEX2WR
> + - description: EMC_PDEX2RD
> + - description: EMC_PCHG2PDEN
> + - description: EMC_ACT2PDEN
> + - description: EMC_AR2PDEN
> + - description: EMC_RW2PDEN
> + - description: EMC_TXSR
> + - description: EMC_TCKE
> + - description: EMC_TFAW
> + - description: EMC_TRPAB
> + - description: EMC_TCLKSTABLE
> + - description: EMC_TCLKSTOP
> + - description: EMC_TREFBW
> + - description: EMC_QUSE_EXTRA
> + - description: EMC_FBIO_CFG6
> + - description: EMC_ODT_WRITE
> + - description: EMC_ODT_READ
> + - description: EMC_FBIO_CFG5
> + - description: EMC_CFG_DIG_DLL
> + - description: EMC_DLL_XFORM_DQS
> + - description: EMC_DLL_XFORM_QUSE
> + - description: EMC_ZCAL_REF_CNT
> + - description: EMC_ZCAL_WAIT_CNT
> + - description: EMC_AUTO_CAL_INTERVAL
> + - description: EMC_CFG_CLKTRIM_0
> + - description: EMC_CFG_CLKTRIM_1
> + - description: EMC_CFG_CLKTRIM_2
> +
> + required:
> + - clock-frequency
> + - compatible
> + - reg
> + - nvidia,emc-registers
> +
> + additionalProperties: false
> +
> + "^emc-tables@[a-z0-9\\-]+$":

Why \ and - in the pattern?

Best regards,
Krzysztof

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