Re: [PATCH v10 06/17] media: uapi: Add controls for Mali-C55 ISP

Sakari Ailus
2025-06-28T20:08:47Z

Hi Daniel,

Thanks for the update.

On 6/24/25 13:21, Daniel Scally wrote:
> Add definitions and documentation for the custom control that will
> be needed by the Mali-C55 ISP driver. This will be a read only
> bitmask of the driver's capabilities, informing userspace of which
> blocks are fitted and which are absent.
>
> Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
> ---
> Changes in v10:
>
> - None
>
> Changes in v9:
>
> - New patch
> ---
> .../userspace-api/media/drivers/index.rst | 1 +
> .../userspace-api/media/drivers/mali-c55.rst | 55 ++++++++++++++++++++++
> include/uapi/linux/media/arm/mali-c55-config.h | 26 ++++++++++
> include/uapi/linux/v4l2-controls.h | 6 +++
> 4 files changed, 88 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
> index d706cb47b1122b6e145a02ab826eb3ecc7997c2b..02967c9b18d6e90f414ccc1329c09bffee895e68 100644
> --- a/Documentation/userspace-api/media/drivers/index.rst
> +++ b/Documentation/userspace-api/media/drivers/index.rst
> @@ -32,6 +32,7 @@ For more details see the file COPYING in the source distribution of Linux.
> cx2341x-uapi
> dw100
> imx-uapi
> + mali-c55
> max2175
> npcm-video
> omap3isp-uapi
> diff --git a/Documentation/userspace-api/media/drivers/mali-c55.rst b/Documentation/userspace-api/media/drivers/mali-c55.rst
> new file mode 100644
> index 0000000000000000000000000000000000000000..e8519da77d737b91a931bbe47920af707eebf110
> --- /dev/null
> +++ b/Documentation/userspace-api/media/drivers/mali-c55.rst
> @@ -0,0 +1,55 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +Arm Mali-C55 ISP driver
> +=======================
> +
> +The Arm Mali-C55 ISP driver implements a single driver-specific control:
> +
> +``V4L2_CID_MALI_C55_CAPABILITIES``

Add: (integer)

?

> + Detail the capabilities of the ISP by giving detail about the fitted blocks.
> +
> + .. flat-table:: Bitmask meaning definitions
> + :header-rows: 1
> + :widths: 2 4 8
> +
> + * - Bit
> + - Macro
> + - Meaning
> + * - 0
> + - MALI_C55_GPS_PONG_FITTED

How about a V4L2 prefix for these? Generally the controls have been
V4L2_CID_something and the macros for the possible values have been
named V4L2_something.

> + - Pong configuration space is fitted in the ISP
> + * - 1
> + - MALI_C55_GPS_WDR_FITTED
> + - WDR Framestitch, offset and gain is fitted in the ISP
> + * - 2
> + - MALI_C55_GPS_COMPRESSION_FITTED
> + - Temper compression is fitted in the ISP
> + * - 3
> + - MALI_C55_GPS_TEMPER_FITTED
> + - Temper is fitted in the ISP
> + * - 4
> + - MALI_C55_GPS_SINTER_LITE_FITTED
> + - Sinter Lite is fitted in the ISP instead of the full Sinter version
> + * - 5
> + - MALI_C55_GPS_SINTER_FITTED
> + - Sinter is fitted in the ISP
> + * - 6
> + - MALI_C55_GPS_IRIDIX_LTM_FITTED
> + - Iridix local tone mappine is fitted in the ISP
> + * - 7
> + - MALI_C55_GPS_IRIDIX_GTM_FITTED
> + - Iridix global tone mapping is fitted in the ISP
> + * - 8
> + - MALI_C55_GPS_CNR_FITTED
> + - Colour noise reduction is fitted in the ISP
> + * - 9
> + - MALI_C55_GPS_FRSCALER_FITTED
> + - The full resolution pipe scaler is fitted in the ISP
> + * - 10
> + - MALI_C55_GPS_DS_PIPE_FITTED
> + - The downscale pipe is fitted in the ISP
> +
> + The Mali-C55 ISP can be configured in a number of ways to include or exclude
> + blocks which may not be necessary. This control provides a way for the
> + driver to communicate to userspace which of the blocks are fitted in the
> + design.
> \ No newline at end of file

Oops.

> diff --git a/include/uapi/linux/media/arm/mali-c55-config.h b/include/uapi/linux/media/arm/mali-c55-config.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..2bd60a0d78786be368c2e51b1a0a63fd2a5f690b
> --- /dev/null
> +++ b/include/uapi/linux/media/arm/mali-c55-config.h
> @@ -0,0 +1,26 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * ARM Mali-C55 ISP Driver - Userspace API
> + *
> + * Copyright (C) 2023 Ideas on Board Oy
> + */
> +
> +#ifndef __UAPI_MALI_C55_CONFIG_H
> +#define __UAPI_MALI_C55_CONFIG_H
> +
> +#include <linux/v4l2-controls.h>
> +
> +#define V4L2_CID_MALI_C55_CAPABILITIES (V4L2_CID_USER_MALI_C55_BASE + 0x0)
> +#define MALI_C55_GPS_PONG_FITTED BIT(0)

Since when has been BIT() defined for UAPI? (1U << x)?

> +#define MALI_C55_GPS_WDR_FITTED BIT(1)
> +#define MALI_C55_GPS_COMPRESSION_FITTED BIT(2)
> +#define MALI_C55_GPS_TEMPER_FITTED BIT(3)
> +#define MALI_C55_GPS_SINTER_LITE_FITTED BIT(4)
> +#define MALI_C55_GPS_SINTER_FITTED BIT(5)
> +#define MALI_C55_GPS_IRIDIX_LTM_FITTED BIT(6)
> +#define MALI_C55_GPS_IRIDIX_GTM_FITTED BIT(7)
> +#define MALI_C55_GPS_CNR_FITTED BIT(8)
> +#define MALI_C55_GPS_FRSCALER_FITTED BIT(9)
> +#define MALI_C55_GPS_DS_PIPE_FITTED BIT(10)
> +
> +#endif /* __UAPI_MALI_C55_CONFIG_H */
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 72e32814ea83dee5f1202c1249eac7cf3b85a22a..a31105115410bd041a3ac492ce86becd93a62d87 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -222,6 +222,12 @@ enum v4l2_colorfx {
> */
> #define V4L2_CID_USER_UVC_BASE (V4L2_CID_USER_BASE + 0x11e0)
>
> +/*
> + * The base for the Arm Mali-C55 ISP driver controls.
> + * We reserve 8 controls for this driver
> + */
> +#define V4L2_CID_USER_MALI_C55_BASE (V4L2_CID_USER_BASE + 0x1220)
> +
> /* MPEG-class control IDs */
> /* The MPEG controls are applicable to all codec controls
> * and the 'MPEG' part of the define is historical */
>

--
Sakari Ailus