[PATCH RFC 11/18] accel/qda: Add GEM_CREATE and GEM_MMAP_OFFSET IOCTLs

[Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>]

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@oss.qualcomm.com>
---
 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