Add PRIME dma-buf import support for QDA GEM buffer objects and integrate it with the existing per-process memory manager and IOMMU device model.
The implementation extends qda_gem_obj to represent imported dma-bufs, including dma_buf references, attachment state, scatter-gather tables and an imported DMA address used for DSP-facing book-keeping. The qda_gem_prime_import() path handles reimports of buffers originally exported by QDA as well as imports of external dma-bufs, attaching them to the assigned IOMMU device and mapping them through the memory manager for DSP access. The GEM free path is updated to unmap and detach imported buffers while preserving the existing behaviour for locally allocated memory.
The PRIME fd-to-handle path is implemented in qda_prime_fd_to_handle(), which records the calling drm_file in a driver-private import context before invoking the core DRM helpers. The GEM import callback retrieves this context to ensure that an IOMMU device is assigned to the process and that imported buffers follow the same per-process IOMMU selection rules as natively allocated GEM objects.
This patch prepares the driver for interoperable buffer sharing between QDA and other dma-buf capable subsystems while keeping IOMMU mapping and lifetime handling consistent with the existing GEM allocation flow.
Signed-off-by: Ekansh Gupta ekansh.gupta@oss.qualcomm.com --- drivers/accel/qda/Makefile | 1 + drivers/accel/qda/qda_drv.c | 8 ++ drivers/accel/qda/qda_drv.h | 4 + drivers/accel/qda/qda_gem.c | 60 +++++++--- drivers/accel/qda/qda_gem.h | 10 ++ drivers/accel/qda/qda_ioctl.c | 7 ++ drivers/accel/qda/qda_ioctl.h | 15 +++ drivers/accel/qda/qda_memory_manager.c | 42 ++++++- drivers/accel/qda/qda_memory_manager.h | 14 +++ drivers/accel/qda/qda_prime.c | 194 +++++++++++++++++++++++++++++++++ drivers/accel/qda/qda_prime.h | 43 ++++++++ 11 files changed, 377 insertions(+), 21 deletions(-)
diff --git a/drivers/accel/qda/Makefile b/drivers/accel/qda/Makefile index 88c324fa382c..8286f5279748 100644 --- a/drivers/accel/qda/Makefile +++ b/drivers/accel/qda/Makefile @@ -13,5 +13,6 @@ qda-y := \ qda_ioctl.o \ qda_gem.o \ qda_memory_dma.o \ + qda_prime.o \
obj-$(CONFIG_DRM_ACCEL_QDA_COMPUTE_BUS) += qda_compute_bus.o diff --git a/drivers/accel/qda/qda_drv.c b/drivers/accel/qda/qda_drv.c index 0dd0e2bb2c0f..4adee00b1f2c 100644 --- a/drivers/accel/qda/qda_drv.c +++ b/drivers/accel/qda/qda_drv.c @@ -10,9 +10,11 @@ #include <drm/drm_gem.h> #include <drm/drm_ioctl.h> #include <drm/qda_accel.h> +#include <drm/drm_prime.h>
#include "qda_drv.h" #include "qda_gem.h" +#include "qda_prime.h" #include "qda_ioctl.h" #include "qda_rpmsg.h"
@@ -166,6 +168,8 @@ static struct drm_driver qda_drm_driver = { .postclose = qda_postclose, .ioctls = qda_ioctls, .num_ioctls = ARRAY_SIZE(qda_ioctls), + .gem_prime_import = qda_gem_prime_import, + .prime_fd_to_handle = qda_ioctl_prime_fd_to_handle, .name = DRIVER_NAME, .desc = "Qualcomm DSP Accelerator Driver", }; @@ -174,6 +178,7 @@ static void cleanup_drm_private(struct qda_dev *qdev) { if (qdev->drm_priv) { qda_dbg(qdev, "Cleaning up DRM private data\n"); + mutex_destroy(&qdev->drm_priv->import_lock); kfree(qdev->drm_priv); } } @@ -240,6 +245,9 @@ static int init_drm_private(struct qda_dev *qdev) if (!qdev->drm_priv) return -ENOMEM;
+ mutex_init(&qdev->drm_priv->import_lock); + qdev->drm_priv->current_import_file_priv = NULL; + qda_dbg(qdev, "DRM private data initialized successfully\n"); return 0; } diff --git a/drivers/accel/qda/qda_drv.h b/drivers/accel/qda/qda_drv.h index 8a2cd474958b..bb0dd7e284c6 100644 --- a/drivers/accel/qda/qda_drv.h +++ b/drivers/accel/qda/qda_drv.h @@ -64,6 +64,10 @@ struct qda_drm_priv { struct qda_memory_manager *iommu_mgr; /* Back-pointer to qda_dev */ struct qda_dev *qdev; + /* Lock protecting import context */ + struct mutex import_lock; + /* Current file_priv during prime import */ + struct drm_file *current_import_file_priv; };
/* struct qda_dev - Main device structure for QDA driver */ diff --git a/drivers/accel/qda/qda_gem.c b/drivers/accel/qda/qda_gem.c index bbd54e2502d3..37279e8b46fe 100644 --- a/drivers/accel/qda/qda_gem.c +++ b/drivers/accel/qda/qda_gem.c @@ -8,6 +8,7 @@ #include "qda_gem.h" #include "qda_memory_manager.h" #include "qda_memory_dma.h" +#include "qda_prime.h"
static int validate_gem_obj_for_mmap(struct qda_gem_obj *qda_gem_obj) { @@ -15,23 +16,29 @@ static int validate_gem_obj_for_mmap(struct qda_gem_obj *qda_gem_obj) qda_err(NULL, "Invalid GEM object size\n"); return -EINVAL; } - if (!qda_gem_obj->iommu_dev || !qda_gem_obj->iommu_dev->dev) { - qda_err(NULL, "Allocated buffer missing IOMMU device\n"); - return -EINVAL; - } - if (!qda_gem_obj->iommu_dev->dev) { - qda_err(NULL, "Allocated buffer missing IOMMU device\n"); - return -EINVAL; - } - if (!qda_gem_obj->virt) { - qda_err(NULL, "Allocated buffer missing virtual address\n"); - return -EINVAL; - } - if (qda_gem_obj->dma_addr == 0) { - qda_err(NULL, "Allocated buffer missing DMA address\n"); - return -EINVAL; + if (qda_gem_obj->is_imported) { + if (!qda_gem_obj->sgt) { + qda_err(NULL, "Imported buffer missing sgt\n"); + return -EINVAL; + } + if (!qda_gem_obj->iommu_dev || !qda_gem_obj->iommu_dev->dev) { + qda_err(NULL, "Imported buffer missing IOMMU device\n"); + return -EINVAL; + } + } else { + if (!qda_gem_obj->iommu_dev || !qda_gem_obj->iommu_dev->dev) { + qda_err(NULL, "Allocated buffer missing IOMMU device\n"); + return -EINVAL; + } + if (!qda_gem_obj->virt) { + qda_err(NULL, "Allocated buffer missing virtual address\n"); + return -EINVAL; + } + if (qda_gem_obj->dma_addr == 0) { + qda_err(NULL, "Allocated buffer missing DMA address\n"); + return -EINVAL; + } } - return 0; }
@@ -60,9 +67,21 @@ void qda_gem_free_object(struct drm_gem_object *gem_obj) struct qda_gem_obj *qda_gem_obj = to_qda_gem_obj(gem_obj); struct qda_drm_priv *drm_priv = get_drm_priv_from_device(gem_obj->dev);
- if (qda_gem_obj->virt) { - if (drm_priv && drm_priv->iommu_mgr) + if (qda_gem_obj->is_imported) { + if (qda_gem_obj->attachment && qda_gem_obj->sgt) + dma_buf_unmap_attachment_unlocked(qda_gem_obj->attachment, + qda_gem_obj->sgt, DMA_BIDIRECTIONAL); + if (qda_gem_obj->attachment) + dma_buf_detach(qda_gem_obj->dma_buf, qda_gem_obj->attachment); + if (qda_gem_obj->dma_buf) + dma_buf_put(qda_gem_obj->dma_buf); + if (qda_gem_obj->iommu_dev && drm_priv && drm_priv->iommu_mgr) qda_memory_manager_free(drm_priv->iommu_mgr, qda_gem_obj); + } else { + if (qda_gem_obj->virt) { + if (drm_priv && drm_priv->iommu_mgr) + qda_memory_manager_free(drm_priv->iommu_mgr, qda_gem_obj); + } }
drm_gem_object_release(gem_obj); @@ -174,6 +193,11 @@ struct drm_gem_object *qda_gem_create_object(struct drm_device *drm_dev, qda_gem_obj = qda_gem_alloc_object(drm_dev, aligned_size); if (IS_ERR(qda_gem_obj)) return (struct drm_gem_object *)qda_gem_obj; + qda_gem_obj->is_imported = false; + qda_gem_obj->dma_buf = NULL; + qda_gem_obj->attachment = NULL; + qda_gem_obj->sgt = NULL; + qda_gem_obj->imported_dma_addr = 0;
ret = qda_memory_manager_alloc(iommu_mgr, qda_gem_obj, file_priv); if (ret) { diff --git a/drivers/accel/qda/qda_gem.h b/drivers/accel/qda/qda_gem.h index cbd5d0a58fa4..3566c5b2ad88 100644 --- a/drivers/accel/qda/qda_gem.h +++ b/drivers/accel/qda/qda_gem.h @@ -31,6 +31,16 @@ struct qda_gem_obj { size_t size; /* IOMMU device that performed the allocation */ struct qda_iommu_device *iommu_dev; + /* True if buffer is imported, false if allocated */ + bool is_imported; + /* Reference to imported dma_buf */ + struct dma_buf *dma_buf; + /* DMA buf attachment */ + struct dma_buf_attachment *attachment; + /* Scatter-gather table */ + struct sg_table *sgt; + /* DMA address of imported buffer */ + dma_addr_t imported_dma_addr; };
/* diff --git a/drivers/accel/qda/qda_ioctl.c b/drivers/accel/qda/qda_ioctl.c index ef3c9c691cb7..d91983048d6c 100644 --- a/drivers/accel/qda/qda_ioctl.c +++ b/drivers/accel/qda/qda_ioctl.c @@ -5,6 +5,7 @@ #include <drm/qda_accel.h> #include "qda_drv.h" #include "qda_ioctl.h" +#include "qda_prime.h"
static int qda_validate_and_get_context(struct drm_device *dev, struct drm_file *file_priv, struct qda_dev **qdev, struct qda_user **qda_user) @@ -78,3 +79,9 @@ int qda_ioctl_gem_mmap_offset(struct drm_device *dev, void *data, struct drm_fil drm_gem_object_put(gem_obj); return ret; } + +int qda_ioctl_prime_fd_to_handle(struct drm_device *dev, struct drm_file *file_priv, int prime_fd, + u32 *handle) +{ + return qda_prime_fd_to_handle(dev, file_priv, prime_fd, handle); +} diff --git a/drivers/accel/qda/qda_ioctl.h b/drivers/accel/qda/qda_ioctl.h index 6bf3bcd28c0e..d454256f5fc5 100644 --- a/drivers/accel/qda/qda_ioctl.h +++ b/drivers/accel/qda/qda_ioctl.h @@ -23,4 +23,19 @@ */ int qda_ioctl_query(struct drm_device *dev, void *data, struct drm_file *file_priv);
+/** + * qda_ioctl_prime_fd_to_handle - IOCTL handler for PRIME FD to handle conversion + * @dev: DRM device structure + * @file_priv: DRM file private data + * @prime_fd: File descriptor of the PRIME buffer + * @handle: Output parameter for the GEM handle + * + * This IOCTL handler converts a PRIME file descriptor to a GEM handle. + * It serves as both the DRM driver callback and can be used directly. + * + * Return: 0 on success, negative error code on failure + */ +int qda_ioctl_prime_fd_to_handle(struct drm_device *dev, struct drm_file *file_priv, + int prime_fd, u32 *handle); + #endif /* _QDA_IOCTL_H */ diff --git a/drivers/accel/qda/qda_memory_manager.c b/drivers/accel/qda/qda_memory_manager.c index e225667557ee..3fd20f17c57b 100644 --- a/drivers/accel/qda/qda_memory_manager.c +++ b/drivers/accel/qda/qda_memory_manager.c @@ -154,8 +154,8 @@ static struct qda_iommu_device *get_process_iommu_device(struct qda_memory_manag return qda_priv->assigned_iommu_dev; }
-static int qda_memory_manager_assign_device(struct qda_memory_manager *mem_mgr, - struct drm_file *file_priv) +int qda_memory_manager_assign_device(struct qda_memory_manager *mem_mgr, + struct drm_file *file_priv) { struct qda_file_priv *qda_priv; struct qda_iommu_device *selected_dev = NULL; @@ -223,6 +223,35 @@ static struct qda_iommu_device *get_or_assign_iommu_device(struct qda_memory_man return NULL; }
+static int qda_memory_manager_map_imported(struct qda_memory_manager *mem_mgr, + struct qda_gem_obj *gem_obj, + struct qda_iommu_device *iommu_dev) +{ + struct scatterlist *sg; + dma_addr_t dma_addr; + int ret = 0; + + if (!gem_obj->is_imported || !gem_obj->sgt || !iommu_dev) { + qda_err(NULL, "Invalid parameters for imported buffer mapping\n"); + return -EINVAL; + } + + gem_obj->iommu_dev = iommu_dev; + + sg = gem_obj->sgt->sgl; + if (sg) { + dma_addr = sg_dma_address(sg); + dma_addr += ((u64)iommu_dev->sid << 32); + + gem_obj->imported_dma_addr = dma_addr; + } else { + qda_err(NULL, "Invalid scatter-gather list for imported buffer\n"); + ret = -EINVAL; + } + + return ret; +} + int qda_memory_manager_alloc(struct qda_memory_manager *mem_mgr, struct qda_gem_obj *gem_obj, struct drm_file *file_priv) { @@ -248,7 +277,10 @@ int qda_memory_manager_alloc(struct qda_memory_manager *mem_mgr, struct qda_gem_ return -ENOMEM; }
- ret = qda_dma_alloc(selected_dev, gem_obj, size); + if (gem_obj->is_imported) + ret = qda_memory_manager_map_imported(mem_mgr, gem_obj, selected_dev); + else + ret = qda_dma_alloc(selected_dev, gem_obj, size);
if (ret) { qda_err(NULL, "Allocation failed: size=%zu, device_id=%u, ret=%d\n", @@ -268,6 +300,10 @@ void qda_memory_manager_free(struct qda_memory_manager *mem_mgr, struct qda_gem_ return; }
+ if (gem_obj->is_imported) { + qda_dbg(NULL, "Freed imported buffer tracking (no DMA free needed)\n"); + return; + } qda_dma_free(gem_obj); }
diff --git a/drivers/accel/qda/qda_memory_manager.h b/drivers/accel/qda/qda_memory_manager.h index bac44284ef98..f6c7963cec42 100644 --- a/drivers/accel/qda/qda_memory_manager.h +++ b/drivers/accel/qda/qda_memory_manager.h @@ -106,6 +106,20 @@ int qda_memory_manager_register_device(struct qda_memory_manager *mem_mgr, void qda_memory_manager_unregister_device(struct qda_memory_manager *mem_mgr, struct qda_iommu_device *iommu_dev);
+/** + * qda_memory_manager_assign_device() - Assign an IOMMU device to a process + * @mem_mgr: Pointer to memory manager + * @file_priv: DRM file private data for process association + * + * Assigns an IOMMU device to the calling process. If the process already has + * a device assigned, returns success. If another file descriptor from the same + * PID has a device, reuses it. Otherwise, finds an available device and assigns it. + * + * Return: 0 on success, negative error code on failure + */ +int qda_memory_manager_assign_device(struct qda_memory_manager *mem_mgr, + struct drm_file *file_priv); + /** * qda_memory_manager_alloc() - Allocate memory for a GEM object * @mem_mgr: Pointer to memory manager diff --git a/drivers/accel/qda/qda_prime.c b/drivers/accel/qda/qda_prime.c new file mode 100644 index 000000000000..3d23842e48bb --- /dev/null +++ b/drivers/accel/qda/qda_prime.c @@ -0,0 +1,194 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. +#include <drm/drm_gem.h> +#include <drm/drm_prime.h> +#include <linux/slab.h> +#include <linux/dma-mapping.h> +#include "qda_drv.h" +#include "qda_gem.h" +#include "qda_prime.h" +#include "qda_memory_manager.h" + +static struct drm_gem_object *check_own_buffer(struct drm_device *dev, struct dma_buf *dma_buf) +{ + if (dma_buf->priv) { + struct drm_gem_object *existing_gem = dma_buf->priv; + + if (existing_gem->dev == dev) { + struct qda_gem_obj *existing_qda_gem = to_qda_gem_obj(existing_gem); + + if (!existing_qda_gem->is_imported) { + drm_gem_object_get(existing_gem); + return existing_gem; + } + } + } + return NULL; +} + +static struct qda_iommu_device *get_iommu_device_for_import(struct qda_drm_priv *drm_priv, + struct drm_file **file_priv_out, + struct qda_dev *qdev) +{ + struct drm_file *file_priv; + struct qda_file_priv *qda_file_priv; + struct qda_iommu_device *iommu_dev = NULL; + int ret; + + file_priv = drm_priv->current_import_file_priv; + *file_priv_out = file_priv; + + if (!file_priv || !file_priv->driver_priv) + return NULL; + + qda_file_priv = (struct qda_file_priv *)file_priv->driver_priv; + iommu_dev = qda_file_priv->assigned_iommu_dev; + + if (!iommu_dev) { + ret = qda_memory_manager_assign_device(drm_priv->iommu_mgr, file_priv); + if (ret) { + qda_err(qdev, "Failed to assign IOMMU device: %d\n", ret); + return NULL; + } + + iommu_dev = qda_file_priv->assigned_iommu_dev; + } + + return iommu_dev; +} + +static int setup_dma_buf_mapping(struct qda_gem_obj *qda_gem_obj, struct dma_buf *dma_buf, + struct device *attach_dev, struct qda_dev *qdev) +{ + struct dma_buf_attachment *attachment; + struct sg_table *sgt; + int ret; + + attachment = dma_buf_attach(dma_buf, attach_dev); + if (IS_ERR(attachment)) { + ret = PTR_ERR(attachment); + qda_err(qdev, "Failed to attach dma_buf: %d\n", ret); + return ret; + } + qda_gem_obj->attachment = attachment; + + sgt = dma_buf_map_attachment_unlocked(attachment, DMA_BIDIRECTIONAL); + if (IS_ERR(sgt)) { + ret = PTR_ERR(sgt); + qda_err(qdev, "Failed to map dma_buf attachment: %d\n", ret); + dma_buf_detach(dma_buf, attachment); + return ret; + } + qda_gem_obj->sgt = sgt; + + return 0; +} + +struct drm_gem_object *qda_gem_prime_import(struct drm_device *dev, struct dma_buf *dma_buf) +{ + struct qda_drm_priv *drm_priv; + struct qda_gem_obj *qda_gem_obj; + struct drm_file *file_priv; + struct qda_iommu_device *iommu_dev; + struct qda_dev *qdev; + struct drm_gem_object *existing_gem; + size_t aligned_size; + int ret; + + drm_priv = get_drm_priv_from_device(dev); + if (!drm_priv || !drm_priv->iommu_mgr) { + qda_err(NULL, "Invalid drm_priv or iommu_mgr\n"); + return ERR_PTR(-EINVAL); + } + + qdev = drm_priv->qdev; + + existing_gem = check_own_buffer(dev, dma_buf); + if (existing_gem) + return existing_gem; + + iommu_dev = get_iommu_device_for_import(drm_priv, &file_priv, qdev); + if (!iommu_dev || !iommu_dev->dev) { + qda_err(qdev, "No IOMMU device assigned for prime import\n"); + return ERR_PTR(-ENODEV); + } + + qda_dbg(qdev, "Using IOMMU device %u for prime import\n", iommu_dev->id); + + aligned_size = PAGE_ALIGN(dma_buf->size); + qda_gem_obj = qda_gem_alloc_object(dev, aligned_size); + if (IS_ERR(qda_gem_obj)) + return (struct drm_gem_object *)qda_gem_obj; + + qda_gem_obj->is_imported = true; + qda_gem_obj->dma_buf = dma_buf; + qda_gem_obj->virt = NULL; + qda_gem_obj->dma_addr = 0; + qda_gem_obj->imported_dma_addr = 0; + qda_gem_obj->iommu_dev = iommu_dev; + + get_dma_buf(dma_buf); + + ret = setup_dma_buf_mapping(qda_gem_obj, dma_buf, iommu_dev->dev, qdev); + if (ret) + goto err_put_dma_buf; + + ret = qda_memory_manager_alloc(drm_priv->iommu_mgr, qda_gem_obj, file_priv); + if (ret) { + qda_err(qdev, "Failed to allocate IOMMU mapping: %d\n", ret); + goto err_unmap; + } + + qda_dbg(qdev, "Prime import completed successfully size=%zu\n", aligned_size); + return &qda_gem_obj->base; + +err_unmap: + dma_buf_unmap_attachment_unlocked(qda_gem_obj->attachment, + qda_gem_obj->sgt, DMA_BIDIRECTIONAL); + dma_buf_detach(dma_buf, qda_gem_obj->attachment); +err_put_dma_buf: + dma_buf_put(dma_buf); + qda_gem_cleanup_object(qda_gem_obj); + return ERR_PTR(ret); +} + +int qda_prime_fd_to_handle(struct drm_device *dev, struct drm_file *file_priv, + int prime_fd, u32 *handle) +{ + struct qda_drm_priv *drm_priv; + struct qda_dev *qdev; + int ret; + + drm_priv = get_drm_priv_from_device(dev); + if (!drm_priv) { + qda_dbg(NULL, "Failed to get drm_priv from device\n"); + return -EINVAL; + } + + qdev = drm_priv->qdev; + + if (file_priv && file_priv->driver_priv) { + struct qda_file_priv *qda_file_priv; + + qda_file_priv = (struct qda_file_priv *)file_priv->driver_priv; + } else { + qda_dbg(qdev, "Called with NULL file_priv or driver_priv\n"); + } + + mutex_lock(&drm_priv->import_lock); + drm_priv->current_import_file_priv = file_priv; + + ret = drm_gem_prime_fd_to_handle(dev, file_priv, prime_fd, handle); + + drm_priv->current_import_file_priv = NULL; + mutex_unlock(&drm_priv->import_lock); + + if (!ret) + qda_dbg(qdev, "Completed with ret=%d, handle=%u\n", ret, *handle); + else + qda_dbg(qdev, "Completed with ret=%d\n", ret); + + return ret; +} + +MODULE_IMPORT_NS("DMA_BUF"); diff --git a/drivers/accel/qda/qda_prime.h b/drivers/accel/qda/qda_prime.h new file mode 100644 index 000000000000..939902454dcd --- /dev/null +++ b/drivers/accel/qda/qda_prime.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. + */ + +#ifndef _QDA_PRIME_H +#define _QDA_PRIME_H + +#include <drm/drm_device.h> +#include <drm/drm_file.h> +#include <drm/drm_gem.h> +#include <linux/dma-buf.h> + +/** + * qda_gem_prime_import - Import a DMA-BUF as a GEM object + * @dev: DRM device structure + * @dma_buf: DMA-BUF to import + * + * This function imports an external DMA-BUF into the QDA driver as a GEM + * object. It handles both re-imports of buffers originally from this driver + * and imports of external buffers from other drivers. + * + * Return: Pointer to the imported GEM object on success, ERR_PTR on failure + */ +struct drm_gem_object *qda_gem_prime_import(struct drm_device *dev, struct dma_buf *dma_buf); + +/** + * qda_prime_fd_to_handle - Core implementation for PRIME FD to GEM handle conversion + * @dev: DRM device structure + * @file_priv: DRM file private data + * @prime_fd: File descriptor of the PRIME buffer + * @handle: Output parameter for the GEM handle + * + * This core function sets up the necessary context before calling the + * DRM framework's prime FD to handle conversion. It ensures proper IOMMU + * device assignment and tracking for the import operation. + * + * Return: 0 on success, negative error code on failure + */ +int qda_prime_fd_to_handle(struct drm_device *dev, struct drm_file *file_priv, + int prime_fd, u32 *handle); + +#endif /* _QDA_PRIME_H */