53 lines
2.6 KiB
YAML
53 lines
2.6 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/mailbox/mediatek,gce-props.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: MediaTek Global Command Engine Common Properties
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maintainers:
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- Houlong Wei <houlong.wei@mediatek.com>
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description:
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The Global Command Engine (GCE) is an instruction based, multi-threaded,
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single-core command dispatcher for MediaTek hardware. The Command Queue
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(CMDQ) mailbox driver is a driver for GCE, implemented using the Linux
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mailbox framework. It is used to receive messages from mailbox consumers
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and configure GCE to execute the specified instruction set in the message.
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We use mediatek,gce-mailbox.yaml to define the properties for CMDQ mailbox
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driver. A device driver that uses the CMDQ driver to configure its hardware
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registers is a mailbox consumer. The mailbox consumer can request a mailbox
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channel corresponding to a GCE hardware thread to send a message, specifying
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that the GCE thread to configure its hardware. The mailbox provider can also
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reserve a mailbox channel to configure GCE hardware register by the specific
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GCE thread. This binding defines the common GCE properties for both mailbox
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provider and consumers.
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properties:
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mediatek,gce-events:
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description:
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GCE has an event table in SRAM, consisting of 1024 event IDs (0~1023).
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Each event ID has a boolean event value with the default value 0.
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The property mediatek,gce-events is used to obtain the event IDs.
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Some gce-events are hardware-bound and cannot be changed by software.
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For instance, in MT8195, when VDO0_MUTEX is stream done, VDO_MUTEX will
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send an event signal to GCE, setting the value of event ID 597 to 1.
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Similarly, in MT8188, the value of event ID 574 will be set to 1 when
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VOD0_MUTEX is stream done.
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On the other hand, some gce-events are not hardware-bound and can be
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changed by software. For example, in MT8188, we can set the value of
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event ID 855, which is not bound to any hardware, to 1 when the driver
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in the secure world completes a task. However, in MT8195, event ID 855
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is already bound to VDEC_LAT1, so we need to select another event ID to
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achieve the same purpose. This event ID can be any ID that is not bound
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to any hardware and is not yet used in any software driver.
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To determine if the event ID is bound to the hardware or used by a
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software driver, refer to the GCE header
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include/dt-bindings/gce/<chip>-gce.h of each chip.
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$ref: /schemas/types.yaml#/definitions/uint32-array
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minItems: 1
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maxItems: 32
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additionalProperties: true
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