Re: [PATCH 08/15] accel/qda: Add QUERY IOCTL and QDA UAPI header

[Dmitry Baryshkov]

On Tue, May 19, 2026 at 11:45:58AM +0530, Ekansh Gupta via B4 Relay wrote:
> From: Ekansh Gupta <ekansh.gupta@xxxxxxxxxxxxxxxx>
> 
> Introduce the DRM_IOCTL_QDA_QUERY IOCTL, which allows user-space to
> identify which DSP domain a given /dev/accel/accel* node represents
> (e.g. "cdsp", "adsp").
> 
> include/uapi/drm/qda_accel.h
>   Defines the QDA IOCTL command numbers and the associated data
>   structures. The header follows the standard DRM UAPI conventions:
>   __u8/__u32 types, a C++ extern "C" guard, and GPL-2.0-only WITH
>   Linux-syscall-note licensing.
> 
> drivers/accel/qda/qda_ioctl.c / qda_ioctl.h
>   Implements qda_ioctl_query(), which copies the DSP domain name
>   stored in qda_dev.dsp_name into the user-supplied drm_qda_query
>   buffer using strscpy().
> 
> drivers/accel/qda/qda_drv.c
>   Registers the qda_ioctls[] table with the drm_driver so that the
>   DRM core dispatches DRM_IOCTL_QDA_QUERY to qda_ioctl_query().
> 
> Assisted-by: Claude:claude-4-6-sonnet
> Signed-off-by: Ekansh Gupta <ekansh.gupta@xxxxxxxxxxxxxxxx>
> ---
>  drivers/accel/qda/Makefile    |  1 +
>  drivers/accel/qda/qda_drv.c   |  8 +++++++
>  drivers/accel/qda/qda_ioctl.c | 26 +++++++++++++++++++++++
>  drivers/accel/qda/qda_ioctl.h | 13 ++++++++++++
>  include/uapi/drm/qda_accel.h  | 49 +++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 97 insertions(+)
> 
> diff --git a/drivers/accel/qda/Makefile b/drivers/accel/qda/Makefile
> index 701fad5ffb50..b658dad35fee 100644
> --- a/drivers/accel/qda/Makefile
> +++ b/drivers/accel/qda/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_DRM_ACCEL_QDA)	:= qda.o
>  qda-y := \
>  	qda_cb.o \
>  	qda_drv.o \
> +	qda_ioctl.o \
>  	qda_memory_manager.o \
>  	qda_rpmsg.o
>  
> diff --git a/drivers/accel/qda/qda_drv.c b/drivers/accel/qda/qda_drv.c
> index 0ad5d9873d7e..becd831d10be 100644
> --- a/drivers/accel/qda/qda_drv.c
> +++ b/drivers/accel/qda/qda_drv.c
> @@ -8,8 +8,10 @@
>  #include <drm/drm_gem.h>
>  #include <drm/drm_ioctl.h>
>  #include <drm/drm_print.h>
> +#include <drm/qda_accel.h>
>  
>  #include "qda_drv.h"
> +#include "qda_ioctl.h"
>  #include "qda_rpmsg.h"
>  
>  static int qda_open(struct drm_device *dev, struct drm_file *file)
> @@ -36,11 +38,17 @@ static void qda_postclose(struct drm_device *dev, struct drm_file *file)
>  
>  DEFINE_DRM_ACCEL_FOPS(qda_accel_fops);
>  
> +static const struct drm_ioctl_desc qda_ioctls[] = {
> +	DRM_IOCTL_DEF_DRV(QDA_QUERY, qda_ioctl_query, 0),
> +};
> +
>  static const struct drm_driver qda_drm_driver = {
>  	.driver_features = DRIVER_COMPUTE_ACCEL,
>  	.fops = &qda_accel_fops,
>  	.open = qda_open,
>  	.postclose = qda_postclose,
> +	.ioctls = qda_ioctls,
> +	.num_ioctls = ARRAY_SIZE(qda_ioctls),
>  	.name = QDA_DRIVER_NAME,
>  	.desc = "Qualcomm DSP Accelerator Driver",
>  };
> diff --git a/drivers/accel/qda/qda_ioctl.c b/drivers/accel/qda/qda_ioctl.c
> new file mode 100644
> index 000000000000..761d3567c33f
> --- /dev/null
> +++ b/drivers/accel/qda/qda_ioctl.c
> @@ -0,0 +1,26 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +// Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> +#include <drm/drm_ioctl.h>
> +#include <drm/qda_accel.h>
> +#include "qda_drv.h"
> +#include "qda_ioctl.h"
> +
> +/**
> + * qda_ioctl_query() - Query DSP device information
> + * @dev: DRM device structure
> + * @data: User-space data (struct drm_qda_query)
> + * @file_priv: DRM file private data
> + *
> + * Return: 0 on success, negative error code on failure
> + */
> +int qda_ioctl_query(struct drm_device *dev, void *data, struct drm_file *file_priv)
> +{
> +	struct drm_qda_query *args = data;
> +	struct qda_dev *qdev;
> +
> +	qdev = qda_dev_from_drm(dev);
> +
> +	strscpy(args->dsp_name, qdev->dsp_name, sizeof(args->dsp_name));
> +
> +	return 0;
> +}
> diff --git a/drivers/accel/qda/qda_ioctl.h b/drivers/accel/qda/qda_ioctl.h
> new file mode 100644
> index 000000000000..b8fd536a111f
> --- /dev/null
> +++ b/drivers/accel/qda/qda_ioctl.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#ifndef __QDA_IOCTL_H__
> +#define __QDA_IOCTL_H__
> +
> +#include "qda_drv.h"
> +
> +int qda_ioctl_query(struct drm_device *dev, void *data, struct drm_file *file_priv);
> +
> +#endif /* __QDA_IOCTL_H__ */
> diff --git a/include/uapi/drm/qda_accel.h b/include/uapi/drm/qda_accel.h
> new file mode 100644
> index 000000000000..1971a4263065
> --- /dev/null
> +++ b/include/uapi/drm/qda_accel.h
> @@ -0,0 +1,49 @@
> +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#ifndef __QDA_ACCEL_H__
> +#define __QDA_ACCEL_H__
> +
> +#include "drm.h"
> +
> +#if defined(__cplusplus)
> +extern "C" {
> +#endif
> +
> +/*
> + * QDA IOCTL command numbers
> + *
> + * These define the command numbers for QDA-specific IOCTLs.
> + * They are used with DRM_COMMAND_BASE to create the full IOCTL numbers.
> + */
> +#define DRM_QDA_QUERY		0x00
> +
> +/*
> + * QDA IOCTL definitions
> + *
> + * These macros define the actual IOCTL numbers used by userspace applications.
> + * They combine the command numbers with DRM_COMMAND_BASE and specify the
> + * data structure and direction (read/write) for each IOCTL.
> + */
> +#define DRM_IOCTL_QDA_QUERY		DRM_IOR(DRM_COMMAND_BASE + DRM_QDA_QUERY, \
> +					 struct drm_qda_query)
> +
> +/**
> + * struct drm_qda_query - Device information query structure
> + * @dsp_name: Name of DSP (e.g., "adsp", "cdsp", "cdsp1", "gdsp0", "gdsp1")
> + *
> + * This structure is used with DRM_IOCTL_QDA_QUERY to query device type,
> + * allowing userspace to identify which DSP a device node represents. The
> + * kernel provides the DSP name directly as a null-terminated string.
> + */
> +struct drm_qda_query {
> +	__u8 dsp_name[16];

Are you sure that you want to query only the name? No extra options, no
attributes, no hardware capabilities?

> +};
> +
> +#if defined(__cplusplus)
> +}
> +#endif
> +
> +#endif /* __QDA_ACCEL_H__ */
> 
> -- 
> 2.34.1
> 
> 

-- 
With best wishes
Dmitry