On 20-05-2026 19:59, Dmitry Baryshkov wrote: > On Tue, May 19, 2026 at 11:45:58AM +0530, Ekansh Gupta via B4 Relay wrote: >> From: Ekansh Gupta <[email protected]> >> >> 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 <[email protected]> >> --- >> 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? There are plans to extend this ioctl to support DSP capabilities and few other query options, but as per my understanding, I don't need to add reserved IOCTLs in drm case and I can extend it in future. Please correct me if my understanding is wrong and I should add reserved fields.
Copying the statement from the doc[1]. "Note that drm_ioctl() automatically zero-extends structures, hence make sure you can add more stuff at the end, i.e. don’t put a variable sized array there." [1] https://www.kernel.org/doc/html/v7.0/gpu/drm-uapi.html#ioctl-support-on-device-nodes> >> +}; >> + >> +#if defined(__cplusplus) >> +} >> +#endif >> + >> +#endif /* __QDA_ACCEL_H__ */ >> >> -- >> 2.34.1 >> >> >
