[PATCH RFC 11/18] accel/qda: Add GEM_CREATE and GEM_MMAP_OFFSET IOCTLs
From: Ekansh Gupta
Date: Mon Feb 23 2026 - 14:17:46 EST
Add two GEM-related IOCTLs for the QDA accelerator driver and hook
them into the DRM accel driver. DRM_IOCTL_QDA_GEM_CREATE allocates
a DMA-backed GEM buffer object via qda_gem_create_object() and
returns a GEM handle to userspace, while
DRM_IOCTL_QDA_GEM_MMAP_OFFSET returns a valid mmap offset for a
given GEM handle using drm_gem_create_mmap_offset() and the
vma_node in the GEM object.
The QDA driver is updated to advertise DRIVER_GEM in its
driver_features, and the new IOCTLs are wired through the QDA
GEM and memory-manager backend. These IOCTLs allow userspace to
allocate buffers and map them into its address space as a first
step toward full compute buffer management and integration with
DSP workloads.
Signed-off-by: Ekansh Gupta <ekansh.gupta@xxxxxxxxxxxxxxxx>
---
drivers/accel/qda/qda_drv.c | 5 ++++-
drivers/accel/qda/qda_gem.h | 30 ++++++++++++++++++++++++++++++
drivers/accel/qda/qda_ioctl.c | 35 +++++++++++++++++++++++++++++++++++
include/uapi/drm/qda_accel.h | 36 ++++++++++++++++++++++++++++++++++++
4 files changed, 105 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qda/qda_drv.c b/drivers/accel/qda/qda_drv.c
index 19798359b14e..0dd0e2bb2c0f 100644
--- a/drivers/accel/qda/qda_drv.c
+++ b/drivers/accel/qda/qda_drv.c
@@ -12,6 +12,7 @@
#include <drm/qda_accel.h>
#include "qda_drv.h"
+#include "qda_gem.h"
#include "qda_ioctl.h"
#include "qda_rpmsg.h"
@@ -154,10 +155,12 @@ 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),
+ DRM_IOCTL_DEF_DRV(QDA_GEM_CREATE, qda_ioctl_gem_create, 0),
+ DRM_IOCTL_DEF_DRV(QDA_GEM_MMAP_OFFSET, qda_ioctl_gem_mmap_offset, 0),
};
static struct drm_driver qda_drm_driver = {
- .driver_features = DRIVER_COMPUTE_ACCEL,
+ .driver_features = DRIVER_GEM | DRIVER_COMPUTE_ACCEL,
.fops = &qda_accel_fops,
.open = qda_open,
.postclose = qda_postclose,
diff --git a/drivers/accel/qda/qda_gem.h b/drivers/accel/qda/qda_gem.h
index caae9cda5363..cbd5d0a58fa4 100644
--- a/drivers/accel/qda/qda_gem.h
+++ b/drivers/accel/qda/qda_gem.h
@@ -47,6 +47,36 @@ struct drm_gem_object *qda_gem_create_object(struct drm_device *drm_dev,
void qda_gem_free_object(struct drm_gem_object *gem_obj);
int qda_gem_mmap_obj(struct drm_gem_object *gem_obj, struct vm_area_struct *vma);
+/*
+ * GEM IOCTL handlers
+ */
+
+/**
+ * qda_ioctl_gem_create - Create a GEM buffer object
+ * @dev: DRM device structure
+ * @data: User-space data containing buffer creation parameters
+ * @file_priv: DRM file private data
+ *
+ * This IOCTL handler creates a new GEM buffer object with the specified
+ * size and returns a handle to the created buffer.
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+int qda_ioctl_gem_create(struct drm_device *dev, void *data, struct drm_file *file_priv);
+
+/**
+ * qda_ioctl_gem_mmap_offset - Get mmap offset for a GEM buffer object
+ * @dev: DRM device structure
+ * @data: User-space data containing buffer handle and offset result
+ * @file_priv: DRM file private data
+ *
+ * This IOCTL handler retrieves the mmap offset for a GEM buffer object,
+ * which can be used to map the buffer into user-space memory.
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+int qda_ioctl_gem_mmap_offset(struct drm_device *dev, void *data, struct drm_file *file_priv);
+
/*
* Helper functions for GEM object allocation and cleanup
* These are used internally and by the PRIME import code
diff --git a/drivers/accel/qda/qda_ioctl.c b/drivers/accel/qda/qda_ioctl.c
index 9fa73ec2dfce..ef3c9c691cb7 100644
--- a/drivers/accel/qda/qda_ioctl.c
+++ b/drivers/accel/qda/qda_ioctl.c
@@ -43,3 +43,38 @@ int qda_ioctl_query(struct drm_device *dev, void *data, struct drm_file *file_pr
return 0;
}
+
+int qda_ioctl_gem_create(struct drm_device *dev, void *data, struct drm_file *file_priv)
+{
+ struct drm_qda_gem_create *args = data;
+ struct drm_gem_object *gem_obj;
+ struct qda_drm_priv *drm_priv;
+
+ drm_priv = get_drm_priv_from_device(dev);
+ if (!drm_priv || !drm_priv->iommu_mgr)
+ return -EINVAL;
+
+ gem_obj = qda_gem_create_object(dev, drm_priv->iommu_mgr, args->size, file_priv);
+ if (IS_ERR(gem_obj))
+ return PTR_ERR(gem_obj);
+
+ return qda_gem_create_handle(file_priv, gem_obj, &args->handle);
+}
+
+int qda_ioctl_gem_mmap_offset(struct drm_device *dev, void *data, struct drm_file *file_priv)
+{
+ struct drm_qda_gem_mmap_offset *args = data;
+ struct drm_gem_object *gem_obj;
+ int ret;
+
+ gem_obj = qda_gem_lookup_object(file_priv, args->handle);
+ if (IS_ERR(gem_obj))
+ return PTR_ERR(gem_obj);
+
+ ret = drm_gem_create_mmap_offset(gem_obj);
+ if (ret == 0)
+ args->offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
+
+ drm_gem_object_put(gem_obj);
+ return ret;
+}
diff --git a/include/uapi/drm/qda_accel.h b/include/uapi/drm/qda_accel.h
index 0aad791c4832..ed24a7f5637e 100644
--- a/include/uapi/drm/qda_accel.h
+++ b/include/uapi/drm/qda_accel.h
@@ -19,6 +19,8 @@ extern "C" {
* They are used with DRM_COMMAND_BASE to create the full IOCTL numbers.
*/
#define DRM_QDA_QUERY 0x00
+#define DRM_QDA_GEM_CREATE 0x01
+#define DRM_QDA_GEM_MMAP_OFFSET 0x02
/*
* QDA IOCTL definitions
*
@@ -27,6 +29,10 @@ extern "C" {
* 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)
+#define DRM_IOCTL_QDA_GEM_CREATE DRM_IOWR(DRM_COMMAND_BASE + DRM_QDA_GEM_CREATE, \
+ struct drm_qda_gem_create)
+#define DRM_IOCTL_QDA_GEM_MMAP_OFFSET DRM_IOWR(DRM_COMMAND_BASE + DRM_QDA_GEM_MMAP_OFFSET, \
+ struct drm_qda_gem_mmap_offset)
/**
* struct drm_qda_query - Device information query structure
@@ -40,6 +46,36 @@ struct drm_qda_query {
__u8 dsp_name[16];
};
+/**
+ * struct drm_qda_gem_create - GEM buffer object creation parameters
+ * @size: Size of the GEM object to create in bytes (input)
+ * @handle: Allocated GEM handle (output)
+ *
+ * This structure is used with DRM_IOCTL_QDA_GEM_CREATE to allocate
+ * a new GEM buffer object.
+ */
+struct drm_qda_gem_create {
+ __u32 handle;
+ __u32 pad;
+ __u64 size;
+};
+
+/**
+ * struct drm_qda_gem_mmap_offset - GEM object mmap offset query
+ * @handle: GEM handle (input)
+ * @pad: Padding for 64-bit alignment
+ * @offset: mmap offset for the GEM object (output)
+ *
+ * This structure is used with DRM_IOCTL_QDA_GEM_MMAP_OFFSET to retrieve
+ * the mmap offset that can be used with mmap() to map the GEM object into
+ * user space.
+ */
+struct drm_qda_gem_mmap_offset {
+ __u32 handle;
+ __u32 pad;
+ __u64 offset;
+};
+
#if defined(__cplusplus)
}
#endif
--
2.34.1