On Mon, Mar 20, 2023 at 09:11:07AM -0600, Jeffrey Hugo wrote:
> +AIC100 defines a number of MHI channels for different purposes. This is a list
> +of the defined channels, and their uses.
> +
> +| QAIC_LOOPBACK
> +| Channels 0 & 1
> +| Valid for AMSS
> +| Any data sent to the device on this channel is sent back to the host.
> +
> +| QAIC_SAHARA
> +| Channels 2 & 3
> +| Valid for SBL
> +| Used by SBL to obtain the runtime firmware from the host.
> +
> +| QAIC_DIAG
> +| Channels 4 & 5
> +| Valid for AMSS
> +| Used to communicate with QSM via the Diag protocol.
> +
> +| QAIC_SSR
> +| Channels 6 & 7
> +| Valid for AMSS
> +| Used to notify the host of subsystem restart events, and to offload SSR crashdumps.
> +
> +| QAIC_QDSS
> +| Channels 8 & 9
> +| Valid for AMSS
> +| Used for the Qualcomm Debug Subsystem.
> +
> +| QAIC_CONTROL
> +| Channels 10 & 11
> +| Valid for AMSS
> +| Used for the Neural Network Control (NNC) protocol.  This is the primary channel between host and
> +  QSM for managing workloads.
> +
> +| QAIC_LOGGING
> +| Channels 12 & 13
> +| Valid for SBL
> +| Used by the SBL to send the bootlog to the host.
> +
> +| QAIC_STATUS
> +| Channels 14 & 15
> +| Valid for AMSS
> +| Used to notify the host of Reliability, Accessibility, Serviceability (RAS) events.
> +
> +| QAIC_TELEMETRY
> +| Channels 16 & 17
> +| Valid for AMSS
> +| Used to get/set power/thermal/etc attributes.
> +
> +| QAIC_DEBUG
> +| Channels 18 & 19
> +| Valid for AMSS
> +| Not used.
> +
> +| QAIC_TIMESYNC
> +| Channels 20 & 21
> +| Valid for SBL/AMSS
> +| Used to synchronize timestamps in the device side logs with the host time source.

For the tabular data above, use table syntax instead.

> +A request FIFO element has the following structure:
> +
> +| {
> +|	u16 req_id;
> +|	u8  seq_id;
> +|	u8  pcie_dma_cmd;
> +|	u32 reserved;
> +|	u64 pcie_dma_source_addr;
> +|	u64 pcie_dma_dest_addr;
> +|	u32 pcie_dma_len;
> +|	u32 reserved;
> +|	u64 doorbell_addr;
> +|	u8  doorbell_attr;
> +|	u8  reserved;
> +|	u16 reserved;
> +|	u32 doorbell_data;
> +|	u32 sem_cmd0;
> +|	u32 sem_cmd1;
> +|	u32 sem_cmd2;
> +|	u32 sem_cmd3;
> +| }

IMO code blocks should better fit the struct listing above.

> +
> +Request field descriptions:
> +
> +| req_id- request ID. A request FIFO element and a response FIFO element with
> +|         the same request ID refer to the same command.
> +
> +| seq_id- sequence ID within a request. Ignored by the DMA Bridge.
> +
> +| pcie_dma_cmd- describes the DMA element of this request.
> +| 	Bit(7) is the force msi flag, which overrides the DMA Bridge MSI logic
> +| 		and generates a MSI when this request is complete, and QSM
> +| 		configures the DMA Bridge to look at this bit.
> +| 	Bits(6:5) are reserved.
> +| 	Bit(4) is the completion code flag, and indicates that the DMA Bridge
> +| 		shall generate a response FIFO element when this request is
> +| 		complete.
> +| 	Bit(3) indicates if this request is a linked list transfer(0) or a bulk
> +| 		transfer(1).
> +| 	Bit(2) is reserved.
> +| 	Bits(1:0) indicate the type of transfer. No transfer(0), to device(1),
> +| 		from device(2). Value 3 is illegal.
> +
> +| pcie_dma_source_addr- source address for a bulk transfer, or the address of
> +|         the linked list.
> +
> +| pcie_dma_dest_addr- destination address for a bulk transfer.
> +
> +| pcie_dma_len- length of the bulk transfer. Note that the size of this field
> +| 	limits transfers to 4G in size.
> +
> +| doorbell_addr- address of the doorbell to ring when this request is complete.
> +
> +| doorbell_attr- doorbell attributes.
> +| 	Bit(7) indicates if a write to a doorbell is to occur.
> +| 	Bits(6:2) are reserved.
> +| 	Bits(1:0) contain the encoding of the doorbell length. 0 is 32-bit,
> +| 		1 is 16-bit, 2 is 8-bit, 3 is reserved. The doorbell address
> +| 		must be naturally aligned to the specified length.
> +
> +| doorbell_data- data to write to the doorbell. Only the bits corresponding to
> +| 	the doorbell length are valid.
> +
> +| sem_cmdN- semaphore command.
> +| 	Bit(31) indicates this semaphore command is enabled.
> +| 	Bit(30) is the to-device DMA fence. Block this request until all
> +| 		to-device DMA transfers are complete.
> +| 	Bit(29) is the from-device DMA fence. Block this request until all
> +| 		from-device DMA transfers are complete.
> +| 	Bits(28:27) are reserved.
> +| 	Bits(26:24) are the semaphore command. 0 is NOP. 1 is init with the
> +| 		specified value. 2 is increment. 3 is decrement. 4 is wait
> +| 		until the semaphore is equal to the specified value. 5 is wait
> +| 		until the semaphore is greater or equal to the specified value.
> +| 		6 is "P", wait until semaphore is greater than 0, then
> +| 		decrement by 1. 7 is reserved.
> +| 	Bit(23) is reserved.
> +| 	Bit(22) is the semaphore sync. 0 is post sync, which means that the
> +| 		semaphore operation is done after the DMA transfer. 1 is
> +| 		presync, which gates the DMA transfer. Only one presync is
> +| 		allowed per request.
> +| 	Bit(21) is reserved.
> +| 	Bits(20:16) is the index of the semaphore to operate on.
> +| 	Bits(15:12) are reserved.
> +| 	Bits(11:0) are the semaphore value to use in operations.

What about bullet lists?

> +
> +| {
> +| 	u16 req_id;
> +| 	u16 completion_code;
> +| }

Again, use code blocks.

> +passthrough- Allows userspace to send an opaque payload directly to the QSM.
> +This is used for NNC commands. Userspace is responsible for managing
> +the QSM message requirements in the payload
> +
> +dma_xfer- DMA transfer. Describes an object that the QSM should DMA into the
> +device via address and size tuples.
> +
> +activate- Activate a workload onto NSPs. The host must provide memory to be
> +used by the DBC.
> +
> +deactivate- Deactivate an active workload and return the NSPs to idle.
> +
> +status- Query the QSM about it's NNC implementation. Returns the NNC version,
> +and if CRC is used.
> +
> +terminate- Release a user's resources.
> +
> +dma_xfer_cont- Continuation of a previous DMA transfer. If a DMA transfer
> +cannot be specified in a single message (highly fragmented), this
> +transaction can be used to specify more ranges.
> +
> +validate_partition- Query to QSM to determine if a partition identifier is
> +valid.

What about using definition lists?

> +DRM_IOCTL_QAIC_MANAGE:
> +This IOCTL allows userspace to send a NNC request to the QSM. The call will
> +block until a response is received, or the request has timed out.
> +
> +DRM_IOCTL_QAIC_CREATE_BO:
> +This IOCTL allows userspace to allocate a buffer object (BO) which can send or
> +receive data from a workload. The call will return a GEM handle that
> +represents the allocated buffer. The BO is not usable until it has been sliced
> +(see DRM_IOCTL_QAIC_ATTACH_SLICE_BO).
> +
> +DRM_IOCTL_QAIC_MMAP_BO:
> +This IOCTL allows userspace to prepare an allocated BO to be mmap'd into the
> +userspace process.
> +
> +DRM_IOCTL_QAIC_ATTACH_SLICE_BO:
> +This IOCTL allows userspace to slice a BO in preparation for sending the BO to
> +the device. Slicing is the operation of describing what portions of a BO get
> +sent where to a workload. This requires a set of DMA transfers for the DMA
> +Bridge, and as such, locks the BO to a specific DBC.
> +
> +DRM_IOCTL_QAIC_EXECUTE_BO:
> +This IOCTL allows userspace to submit a set of sliced BOs to the device. The
> +call is non-blocking. Success only indicates that the BOs have been queued
> +to the device, but does not guarantee they have been executed.
> +
> +DRM_IOCTL_QAIC_PARTIAL_EXECUTE_BO:
> +This IOCTL operates like DRM_IOCTL_QAIC_EXECUTE_BO, but it allows userspace to
> +shrink the BOs sent to the device for this specific call. If a BO typically has
> +N inputs, but only a subset of those is available, this IOCTL allows userspace
> +to indicate that only the first M bytes of the BO should be sent to the device
> +to minimize data transfer overhead. This IOCTL dynamically recomputes the
> +slicing, and therefore has some processing overhead before the BOs can be queued
> +to the device.
> +
> +DRM_IOCTL_QAIC_WAIT_BO:
> +This IOCTL allows userspace to determine when a particular BO has been processed
> +by the device. The call will block until either the BO has been processed and
> +can be re-queued to the device, or a timeout occurs.
> +
> +DRM_IOCTL_QAIC_PERF_STATS_BO:
> +This IOCTL allows userspace to collect performance statistics on the most
> +recent execution of a BO. This allows userspace to construct an end to end
> +timeline of the BO processing for a performance analysis.
> +
> +DRM_IOCTL_QAIC_PART_DEV:
> +This IOCTL allows userspace to request a duplicate "shadow device". This extra
> +accelN device is associated with a specific partition of resources on the AIC100
> +device and can be used for limiting a process to some subset of resources.

Again, I'd like to see definition lists for above.

See Sphinx primer [1] for examples of markups I point above.

Thanks.

[1]: https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html

-- 
An old man doll... just what I always wanted! - Clara