Ahoy--
On 12/1/20 2:35 PM, mgross@xxxxxxxxxxxxxxx wrote:
> From: Seamus Kelly <seamus.kelly@xxxxxxxxx>
>
> Add xLink driver, which interfaces the xLink Core driver with the Keem
> Bay VPU IPC driver, thus enabling xLink to control and communicate with
> the VPU IP present on the Intel Keem Bay SoC.
>
> Specifically the driver enables xLink Core to:
>
> * Boot / Reset the VPU IP
> * Register to VPU IP event notifications (device connected, device
> disconnected, WDT event)
> * Query the status of the VPU IP (OFF, BUSY, READY, ERROR, RECOVERY)
> * Exchange data with the VPU IP, using the Keem Bay IPC mechanism
> - Including the ability to send 'volatile' data (i.e., small amount of
> data, up to 128-bytes that was not allocated in the CPU/VPU shared
> memory region)
>
> Cc: linux-doc@xxxxxxxxxxxxxxx
> Reviewed-by: Mark Gross <mgross@xxxxxxxxxxxxxxx>
> Signed-off-by: Seamus Kelly <seamus.kelly@xxxxxxxxx>
> Signed-off-by: Ryan Carnaghi <ryan.r.carnaghi@xxxxxxxxx>
> ---
> Documentation/vpu/index.rst | 1 +
> Documentation/vpu/xlink-ipc.rst | 50 ++
> MAINTAINERS | 6 +
> drivers/misc/Kconfig | 1 +
> drivers/misc/Makefile | 1 +
> drivers/misc/xlink-ipc/Kconfig | 7 +
> drivers/misc/xlink-ipc/Makefile | 4 +
> drivers/misc/xlink-ipc/xlink-ipc.c | 879 +++++++++++++++++++++++++++++
> include/linux/xlink-ipc.h | 48 ++
> 9 files changed, 997 insertions(+)
> create mode 100644 Documentation/vpu/xlink-ipc.rst
> create mode 100644 drivers/misc/xlink-ipc/Kconfig
> create mode 100644 drivers/misc/xlink-ipc/Makefile
> create mode 100644 drivers/misc/xlink-ipc/xlink-ipc.c
> create mode 100644 include/linux/xlink-ipc.h
> diff --git a/Documentation/vpu/xlink-ipc.rst b/Documentation/vpu/xlink-ipc.rst
> new file mode 100644
> index 000000000000..af583579e70d
> --- /dev/null
> +++ b/Documentation/vpu/xlink-ipc.rst
> @@ -0,0 +1,50 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +Kernel driver: xLink IPC driver
> +=================================
> +Supported chips:
> +
> +* | Intel Edge.AI Computer Vision platforms: Keem Bay
> + | Suffix: Bay
> + | Datasheet: (not yet publicly available)
> +
> +------------
> +Introduction
> +------------
> +
> +The xLink IPC driver interfaces the xLink Core driver with the Keem Bay VPU IPC
> +driver, thus enabling xLink to control and communicate with the VPU IP present
> +on the Intel Keem Bay SoC.
> +
> +Specifically the driver enables xLink Core to:
> +
> +* Boot / Reset the VPU IP
> +* Register to VPU IP event notifications (device connected, device disconnected,
> + WDT event)
> +* Query the status of the VPU IP (OFF, BUSY, READY, ERROR, RECOVERY)
> +* Exchange data with the VPU IP, using the Keem Bay IPC mechanism
> +
> + * Including the ability to send 'volatile' data (i.e., small amount of data,
> + up to 128-bytes that was not allocated in the CPU/VPU shared memory region)
> +
> +Sending / Receiving 'volatile' data
> +-----------------------------------
> +
> +Data to be exchanged with Keem Bay IPC needs to be allocated in the portion of
> +DDR shared between the CPU and VPU.
> +
> +This can be impractical for small amount of data that user code can allocate
amounts
> +on the stack.
> +
> +To reduce the burden on user code, xLink Core provides special send / receive
> +functions to send up to 128 bytes of 'volatile data', i.e., data that is not
> +allocated in the shared memory and that might also disappear after the xLink
> +API is called (e.g., because allocated on the stack).
> +
> +The xLink IPC driver implements support for transferring such 'volatile data'
> +to the VPU using Keem Bay IPC. To this end, the driver reserved some memory in
better: reserves
> +the shared memory region.
> +
> +When volatile data is to be sent, xLink IPC allocates a buffer from the
> +reserved memory region and copies the volatile data to the buffer. The buffer
> +is then transferred to the VPU using Keem Bay IPC.
> diff --git a/drivers/misc/xlink-ipc/Kconfig b/drivers/misc/xlink-ipc/Kconfig
> new file mode 100644
> index 000000000000..6aa2592fe9a3
> --- /dev/null
> +++ b/drivers/misc/xlink-ipc/Kconfig
> @@ -0,0 +1,7 @@
> +config XLINK_IPC
> + tristate "Support for XLINK IPC"
> + depends on KEEMBAY_VPU_IPC
> + help
> + XLINK IPC enables the communication/control IPC Sub-System.
> +
> + Select M if you have an Intel SoC with a Vision Processing Unit (VPU)
End that sentence with a '.', please.
--
~Randy
