[PATCH v2 09/15] accel/qda: Add DMA-backed GEM objects and memory manager integration
Ekansh Gupta <[email protected]>
| Newsgroups | gmane.linux.drivers.video-input-infrastructure,gmane.linux.kernel,gmane.comp.video.dri.devel,gmane.linux.documentation,gmane.linux.ports.arm.msm |
|---|---|
| Message-ID | <[email protected]> |
Introduce DMA-coherent buffer management for the QDA driver, wiring together the GEM subsystem, the IOMMU memory manager, and a DMA allocation backend. qda_gem.c / qda_gem.h Implements the GEM object lifecycle for QDA buffers. Each buffer is represented by a qda_gem_obj which embeds a drm_gem_object and carries the kernel virtual address, DMA address, and a pointer to the IOMMU device that performed the allocation. The .free callback delegates to the memory manager, and the .mmap callback uses dma_mmap_coherent() via the DMA backend. qda_memory_dma.c / qda_memory_dma.h DMA coherent allocation backend. qda_dma_alloc() calls dma_alloc_coherent() on the CB device and encodes the stream ID (SID) in the upper 32 bits of the returned DMA address, following the Qualcomm FastRPC convention for IOMMU address space tagging. qda_dma_free() strips the SID prefix before calling dma_free_coherent(). qda_memory_manager.c Adds process-to-device assignment: each DRM file (process) is assigned one IOMMU context bank device for the lifetime of the session. qda_memory_manager_assign_device() first checks whether the process already has a device (reusing it with a refcount increment), then falls back to claiming an unassigned device. qda_memory_manager_alloc() and qda_memory_manager_free() delegate to the DMA backend after resolving the correct CB device for the calling process. qda_drv.c / qda_drv.h qda_file_priv gains an assigned_iommu_dev pointer and a pid field. The .postclose callback decrements the IOMMU device refcount and clears the process assignment when the last reference is dropped. Assisted-by: Claude:claude-sonnet-5 Signed-off-by: Ekansh Gupta <[email protected]> --- Changes in v2: - Adapt to the dynamically-sized device array introduced in patch 07 (kcalloc'd from DT node count, replaces fixed QDA_IOMMU_DEVICES_MAX) - Protect register/unregister with the process_assignment_lock mutex so the device-assignment and device-registration paths are serialised - No functional changes requested by reviewers on this patch --- drivers/accel/qda/Makefile | 2 + drivers/accel/qda/qda_drv.c | 4 + drivers/accel/qda/qda_drv.h | 4 + drivers/accel/qda/qda_gem.c | 134 ++++++++++++++++++ drivers/accel/qda/qda_gem.h | 52 +++++++ drivers/accel/qda/qda_memory_dma.c | 82 +++++++++++ drivers/accel/qda/qda_memory_dma.h | 17 +++ drivers/accel/qda/qda_memory_manager.c | 239 ++++++++++++++++++++++++++++++++- drivers/accel/qda/qda_memory_manager.h | 30 +++++ 9 files changed, 559 insertions(+), 5 deletions(-) diff --git a/drivers/accel/qda/Makefile b/drivers/accel/qda/Makefile index b658dad35fee..a46ddceecfc5 100644 --- a/drivers/accel/qda/Makefile +++ b/drivers/accel/qda/Makefile @@ -8,7 +8,9 @@ obj-$(CONFIG_DRM_ACCEL_QDA) := qda.o qda-y := \ qda_cb.o \ qda_drv.o \ + qda_gem.o \ qda_ioctl.o \ + qda_memory_dma.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 e1fd8bfa12d7..2b14dab95507 100644 --- a/drivers/accel/qda/qda_drv.c +++ b/drivers/accel/qda/qda_drv.c @@ -21,6 +21,7 @@ static int qda_open(struct drm_device *dev, struct drm_file *file) if (!qda_file_priv) return -ENOMEM; + qda_file_priv->pid = current->pid; qda_file_priv->qda_dev = qda_dev_from_drm(dev); file->driver_priv = qda_file_priv; @@ -31,6 +32,9 @@ static void qda_postclose(struct drm_device *dev, struct drm_file *file) { struct qda_file_priv *qda_file_priv = file->driver_priv; + if (qda_file_priv->assigned_iommu_dev) + qda_memory_manager_release_device(qda_file_priv->assigned_iommu_dev); + kfree(qda_file_priv); file->driver_priv = NULL; } diff --git a/drivers/accel/qda/qda_drv.h b/drivers/accel/qda/qda_drv.h index 690a833d732b..2fe58f3efec0 100644 --- a/drivers/accel/qda/qda_drv.h +++ b/drivers/accel/qda/qda_drv.h @@ -24,6 +24,10 @@ struct qda_file_priv { /** @qda_dev: Back-pointer to device structure */ struct qda_dev *qda_dev; + /** @assigned_iommu_dev: IOMMU device assigned to this process */ + struct qda_iommu_device *assigned_iommu_dev; + /** @pid: Process ID for tracking */ + pid_t pid; }; /** diff --git a/drivers/accel/qda/qda_gem.c b/drivers/accel/qda/qda_gem.c new file mode 100644 index 000000000000..66e78013a726 --- /dev/null +++ b/drivers/accel/qda/qda_gem.c @@ -0,0 +1,134 @@ +// 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 <drm/drm_print.h> +#include <linux/slab.h> +#include <linux/dma-mapping.h> +#include "qda_drv.h" +#include "qda_gem.h" +#include "qda_memory_manager.h" +#include "qda_memory_dma.h" + +/** + * qda_gem_free_object() - Free a GEM object and its associated resources + * @gem_obj: DRM GEM object to free + */ +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_dev *qdev = qda_dev_from_drm(gem_obj->dev); + + if (qda_gem_obj->virt && qdev->iommu_mgr) + qda_memory_manager_free(qdev->iommu_mgr, qda_gem_obj); + + drm_gem_object_release(gem_obj); + kfree(qda_gem_obj); +} + +/** + * qda_gem_mmap_obj() - Map a GEM object into userspace + * @drm_obj: DRM GEM object to map + * @vma: Virtual memory area to map into + * + * Return: 0 on success, negative error code on failure + */ +int qda_gem_mmap_obj(struct drm_gem_object *drm_obj, struct vm_area_struct *vma) +{ + struct qda_gem_obj *qda_gem_obj = to_qda_gem_obj(drm_obj); + int ret; + + /* The fake offset is only used to find the object, not to index it */ + vma->vm_pgoff = 0; + + ret = qda_dma_mmap(qda_gem_obj, vma); + if (ret) + return ret; + + vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP); + + return 0; +} + +static const struct drm_gem_object_funcs qda_gem_object_funcs = { + .free = qda_gem_free_object, + .mmap = qda_gem_mmap_obj, +}; + +/** + * qda_gem_alloc_object() - Allocate a new QDA GEM object + * @drm_dev: DRM device + * @aligned_size: Size of the object in bytes (must be page-aligned) + * + * Return: Pointer to the new GEM object, or ERR_PTR on failure + */ +struct qda_gem_obj *qda_gem_alloc_object(struct drm_device *drm_dev, size_t aligned_size) +{ + struct qda_gem_obj *qda_gem_obj; + int ret; + + qda_gem_obj = kzalloc_obj(*qda_gem_obj); + if (!qda_gem_obj) + return ERR_PTR(-ENOMEM); + + ret = drm_gem_object_init(drm_dev, &qda_gem_obj->base, aligned_size); + if (ret) { + kfree(qda_gem_obj); + return ERR_PTR(ret); + } + + qda_gem_obj->base.funcs = &qda_gem_object_funcs; + qda_gem_obj->size = aligned_size; + + return qda_gem_obj; +} + +void qda_gem_cleanup_object(struct qda_gem_obj *qda_gem_obj) +{ + drm_gem_object_release(&qda_gem_obj->base); + kfree(qda_gem_obj); +} + +int qda_gem_create_handle(struct drm_file *file_priv, struct drm_gem_object *gem_obj, u32 *handle) +{ + int ret; + + ret = drm_gem_handle_create(file_priv, gem_obj, handle); + drm_gem_object_put(gem_obj); + + return ret; +} + +/** + * qda_gem_create_object() - Allocate and initialize a GEM object with DMA backing + * @drm_dev: DRM device + * @iommu_mgr: Memory manager to use for DMA allocation + * @size: Requested size in bytes + * @file_priv: DRM file private data for process association + * + * Return: Pointer to the base DRM GEM object on success, ERR_PTR on failure + */ +struct drm_gem_object *qda_gem_create_object(struct drm_device *drm_dev, + struct qda_memory_manager *iommu_mgr, size_t size, + struct drm_file *file_priv) +{ + struct qda_gem_obj *qda_gem_obj; + size_t aligned_size; + int ret; + + aligned_size = PAGE_ALIGN(size); + if (!aligned_size) + return ERR_PTR(-EINVAL); + + qda_gem_obj = qda_gem_alloc_object(drm_dev, aligned_size); + if (IS_ERR(qda_gem_obj)) + return ERR_CAST(qda_gem_obj); + + ret = qda_memory_manager_alloc(iommu_mgr, qda_gem_obj, file_priv); + if (ret) { + qda_gem_cleanup_object(qda_gem_obj); + return ERR_PTR(ret); + } + + return &qda_gem_obj->base; +} diff --git a/drivers/accel/qda/qda_gem.h b/drivers/accel/qda/qda_gem.h new file mode 100644 index 000000000000..afd7c9b49549 --- /dev/null +++ b/drivers/accel/qda/qda_gem.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. + */ +#ifndef __QDA_GEM_H__ +#define __QDA_GEM_H__ + +#include <linux/dma-mapping.h> +#include <drm/drm_device.h> +#include <drm/drm_gem.h> +#include "qda_memory_manager.h" + +/** + * struct qda_gem_obj - QDA GEM buffer object + * + * Represents a GEM buffer object that can be allocated by the driver + * or imported from another driver via DMA-BUF. + */ +struct qda_gem_obj { + /** @base: DRM GEM object base — must be first member */ + struct drm_gem_object base; + /** @iommu_dev: IOMMU context bank device that performed the allocation */ + struct qda_iommu_device *iommu_dev; + /** @virt: Kernel virtual address of the allocated DMA memory */ + void *virt; + /** @dma_addr: DMA address (with SID encoded in upper 32 bits) */ + dma_addr_t dma_addr; + /** @size: Size of the buffer in bytes */ + size_t size; +}; + +/** + * to_qda_gem_obj - Cast a drm_gem_object pointer to qda_gem_obj + * @gem_obj: Pointer to the embedded drm_gem_object + */ +#define to_qda_gem_obj(gem_obj) container_of(gem_obj, struct qda_gem_obj, base) + +/* GEM object lifecycle */ +struct drm_gem_object *qda_gem_create_object(struct drm_device *drm_dev, + struct qda_memory_manager *iommu_mgr, + size_t size, struct drm_file *file_priv); +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); + +/* Internal helpers (also used by PRIME import) */ +struct qda_gem_obj *qda_gem_alloc_object(struct drm_device *drm_dev, size_t aligned_size); +void qda_gem_cleanup_object(struct qda_gem_obj *qda_gem_obj); + +/* Utility functions */ +int qda_gem_create_handle(struct drm_file *file_priv, struct drm_gem_object *gem_obj, u32 *handle); + +#endif /* __QDA_GEM_H__ */ diff --git a/drivers/accel/qda/qda_memory_dma.c b/drivers/accel/qda/qda_memory_dma.c new file mode 100644 index 000000000000..7072ed8edf0b --- /dev/null +++ b/drivers/accel/qda/qda_memory_dma.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. +#include <linux/slab.h> +#include <linux/dma-mapping.h> +#include "qda_drv.h" +#include "qda_gem.h" +#include "qda_memory_dma.h" + +/* + * The DSP identifies the IOMMU context bank from the upper bits of the address, + * so the stream ID is folded into every address handed to it. The DMA API only + * ever sees the plain 32-bit address, which is why the context bank devices are + * created with a 32-bit DMA mask. + */ +static dma_addr_t get_actual_dma_addr(struct qda_gem_obj *gem_obj) +{ + return gem_obj->dma_addr - ((u64)gem_obj->iommu_dev->sid << 32); +} + +static void setup_gem_object(struct qda_gem_obj *gem_obj, void *virt, + dma_addr_t dma_addr, struct qda_iommu_device *iommu_dev) +{ + gem_obj->virt = virt; + gem_obj->dma_addr = dma_addr; + gem_obj->iommu_dev = iommu_dev; +} + +static void cleanup_gem_object_fields(struct qda_gem_obj *gem_obj) +{ + gem_obj->virt = NULL; + gem_obj->dma_addr = 0; + gem_obj->iommu_dev = NULL; +} + +/** + * qda_dma_alloc() - Allocate DMA coherent memory for a GEM object + * @iommu_dev: Pointer to the QDA IOMMU device structure + * @gem_obj: Pointer to GEM object to allocate memory for + * @size: Size of memory to allocate in bytes + * + * Return: 0 on success, negative error code on failure + */ +int qda_dma_alloc(struct qda_iommu_device *iommu_dev, + struct qda_gem_obj *gem_obj, size_t size) +{ + dma_addr_t dma_addr; + void *virt; + + virt = dma_alloc_coherent(iommu_dev->dev, size, &dma_addr, GFP_KERNEL); + if (!virt) + return -ENOMEM; + + dma_addr += ((u64)iommu_dev->sid << 32); + setup_gem_object(gem_obj, virt, dma_addr, iommu_dev); + + return 0; +} + +/** + * qda_dma_free() - Free DMA coherent memory for a GEM object + * @gem_obj: Pointer to GEM object to free memory for + */ +void qda_dma_free(struct qda_gem_obj *gem_obj) +{ + dma_free_coherent(gem_obj->iommu_dev->dev, gem_obj->size, + gem_obj->virt, get_actual_dma_addr(gem_obj)); + + cleanup_gem_object_fields(gem_obj); +} + +/** + * qda_dma_mmap() - Map DMA memory into userspace + * @gem_obj: Pointer to GEM object containing DMA memory + * @vma: Virtual memory area to map into + * + * Return: 0 on success, negative error code on failure + */ +int qda_dma_mmap(struct qda_gem_obj *gem_obj, struct vm_area_struct *vma) +{ + return dma_mmap_coherent(gem_obj->iommu_dev->dev, vma, gem_obj->virt, + get_actual_dma_addr(gem_obj), gem_obj->size); +} diff --git a/drivers/accel/qda/qda_memory_dma.h b/drivers/accel/qda/qda_memory_dma.h new file mode 100644 index 000000000000..99352a99dc33 --- /dev/null +++ b/drivers/accel/qda/qda_memory_dma.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. + */ + +#ifndef __QDA_MEMORY_DMA_H__ +#define __QDA_MEMORY_DMA_H__ + +#include <linux/dma-mapping.h> +#include "qda_memory_manager.h" + +int qda_dma_alloc(struct qda_iommu_device *iommu_dev, + struct qda_gem_obj *gem_obj, size_t size); +void qda_dma_free(struct qda_gem_obj *gem_obj); +int qda_dma_mmap(struct qda_gem_obj *gem_obj, struct vm_area_struct *vma); + +#endif /* __QDA_MEMORY_DMA_H__ */ diff --git a/drivers/accel/qda/qda_memory_manager.c b/drivers/accel/qda/qda_memory_manager.c index b1a80ee77c35..d47c7419e11d 100644 --- a/drivers/accel/qda/qda_memory_manager.c +++ b/drivers/accel/qda/qda_memory_manager.c @@ -1,14 +1,26 @@ // SPDX-License-Identifier: GPL-2.0-only // Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. +#include <linux/refcount.h> #include <linux/slab.h> +#include <linux/spinlock.h> +#include <drm/drm_file.h> +#include <drm/drm_print.h> #include "qda_drv.h" +#include "qda_gem.h" #include "qda_memory_manager.h" +#include "qda_memory_dma.h" + +static void iommu_device_free(struct kref *ref) +{ + kfree(container_of(ref, struct qda_iommu_device, ref)); +} static void cleanup_all_memory_devices(struct qda_memory_manager *mem_mgr) { int i; + mutex_lock(&mem_mgr->process_assignment_lock); for (i = 0; i < mem_mgr->num_devices; i++) { struct qda_iommu_device *iommu_dev = mem_mgr->devices[i]; @@ -16,9 +28,215 @@ static void cleanup_all_memory_devices(struct qda_memory_manager *mem_mgr) continue; mem_mgr->devices[i] = NULL; - kfree(iommu_dev); + kref_put(&iommu_dev->ref, iommu_device_free); } mem_mgr->num_devices = 0; + mutex_unlock(&mem_mgr->process_assignment_lock); +} + +static void init_iommu_device_fields(struct qda_iommu_device *iommu_dev) +{ + spin_lock_init(&iommu_dev->lock); + refcount_set(&iommu_dev->users, 0); + kref_init(&iommu_dev->ref); + iommu_dev->assigned_pid = 0; + iommu_dev->assigned_file_priv = NULL; +} + +static struct qda_iommu_device *find_device_for_pid(struct qda_memory_manager *mem_mgr, + pid_t pid) +{ + struct qda_iommu_device *found_dev = NULL; + unsigned long flags; + int i; + + for (i = 0; i < mem_mgr->num_devices; i++) { + struct qda_iommu_device *iommu_dev = mem_mgr->devices[i]; + + if (!iommu_dev) + continue; + + spin_lock_irqsave(&iommu_dev->lock, flags); + if (iommu_dev->assigned_pid == pid) { + found_dev = iommu_dev; + refcount_inc(&found_dev->users); + kref_get(&found_dev->ref); + spin_unlock_irqrestore(&iommu_dev->lock, flags); + break; + } + spin_unlock_irqrestore(&iommu_dev->lock, flags); + } + + return found_dev; +} + +static struct qda_iommu_device *assign_available_device_to_pid(struct qda_memory_manager *mem_mgr, + pid_t pid, + struct drm_file *file_priv) +{ + struct qda_iommu_device *selected_dev = NULL; + unsigned long flags; + int i; + + for (i = 0; i < mem_mgr->num_devices; i++) { + struct qda_iommu_device *iommu_dev = mem_mgr->devices[i]; + + if (!iommu_dev) + continue; + + spin_lock_irqsave(&iommu_dev->lock, flags); + if (iommu_dev->assigned_pid == 0) { + iommu_dev->assigned_pid = pid; + iommu_dev->assigned_file_priv = file_priv; + selected_dev = iommu_dev; + refcount_set(&selected_dev->users, 1); + kref_get(&selected_dev->ref); + spin_unlock_irqrestore(&iommu_dev->lock, flags); + break; + } + spin_unlock_irqrestore(&iommu_dev->lock, flags); + } + + return selected_dev; +} + +static struct qda_iommu_device *get_process_iommu_device(struct qda_memory_manager *mem_mgr, + struct drm_file *file_priv) +{ + struct qda_file_priv *qda_priv; + + if (!file_priv || !file_priv->driver_priv) + return NULL; + + qda_priv = (struct qda_file_priv *)file_priv->driver_priv; + return qda_priv->assigned_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 + * + * On success the caller owns a reference on the device and must release it + * with qda_memory_manager_release_device(). + * + * 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) +{ + struct qda_file_priv *qda_priv; + struct qda_iommu_device *selected_dev = NULL; + int ret = 0; + pid_t current_pid; + + if (!file_priv || !file_priv->driver_priv) + return -EINVAL; + + qda_priv = (struct qda_file_priv *)file_priv->driver_priv; + current_pid = qda_priv->pid; + + mutex_lock(&mem_mgr->process_assignment_lock); + + if (qda_priv->assigned_iommu_dev) { + ret = 0; + goto unlock_and_return; + } + + selected_dev = find_device_for_pid(mem_mgr, current_pid); + + if (selected_dev) { + qda_priv->assigned_iommu_dev = selected_dev; + goto unlock_and_return; + } + + selected_dev = assign_available_device_to_pid(mem_mgr, current_pid, file_priv); + + if (!selected_dev) { + drm_dbg_driver(file_priv->minor->dev, "No context bank available for PID %d\n", + current_pid); + ret = -EBUSY; + goto unlock_and_return; + } + + qda_priv->assigned_iommu_dev = selected_dev; + +unlock_and_return: + mutex_unlock(&mem_mgr->process_assignment_lock); + + return ret; +} + +/** + * qda_memory_manager_release_device() - Release a process assignment + * @iommu_dev: Device previously obtained from qda_memory_manager_assign_device() + * + * Drops the caller's reference. Once the last process using the device is + * gone the assignment is cleared so the device can serve another process. + */ +void qda_memory_manager_release_device(struct qda_iommu_device *iommu_dev) +{ + unsigned long flags; + + if (refcount_dec_and_test(&iommu_dev->users)) { + spin_lock_irqsave(&iommu_dev->lock, flags); + iommu_dev->assigned_pid = 0; + iommu_dev->assigned_file_priv = NULL; + spin_unlock_irqrestore(&iommu_dev->lock, flags); + } + + kref_put(&iommu_dev->ref, iommu_device_free); +} + +static struct qda_iommu_device *get_or_assign_iommu_device(struct qda_memory_manager *mem_mgr, + struct drm_file *file_priv) +{ + struct qda_iommu_device *iommu_dev; + int ret; + + iommu_dev = get_process_iommu_device(mem_mgr, file_priv); + if (iommu_dev) + return iommu_dev; + + ret = qda_memory_manager_assign_device(mem_mgr, file_priv); + if (ret) + return NULL; + + iommu_dev = get_process_iommu_device(mem_mgr, file_priv); + if (iommu_dev) + return iommu_dev; + + return NULL; +} + +/** + * qda_memory_manager_alloc() - Allocate memory for a GEM object + * @mem_mgr: Pointer to memory manager + * @gem_obj: Pointer to GEM object to allocate memory for + * @file_priv: DRM file private data for process association + * + * Return: 0 on success, negative error code on failure + */ +int qda_memory_manager_alloc(struct qda_memory_manager *mem_mgr, struct qda_gem_obj *gem_obj, + struct drm_file *file_priv) +{ + struct qda_iommu_device *selected_dev; + + selected_dev = get_or_assign_iommu_device(mem_mgr, file_priv); + if (!selected_dev) + return -EBUSY; + + return qda_dma_alloc(selected_dev, gem_obj, gem_obj->size); +} + +/** + * qda_memory_manager_free() - Free memory for a GEM object + * @mem_mgr: Pointer to memory manager + * @gem_obj: Pointer to GEM object to free memory for + */ +void qda_memory_manager_free(struct qda_memory_manager *mem_mgr, struct qda_gem_obj *gem_obj) +{ + qda_dma_free(gem_obj); } /** @@ -31,13 +249,21 @@ static void cleanup_all_memory_devices(struct qda_memory_manager *mem_mgr) int qda_memory_manager_register_device(struct qda_memory_manager *mem_mgr, struct qda_iommu_device *iommu_dev) { - if (mem_mgr->num_devices >= mem_mgr->max_devices) - return -ENOSPC; + int ret = 0; + mutex_lock(&mem_mgr->process_assignment_lock); + if (mem_mgr->num_devices >= mem_mgr->max_devices) { + ret = -ENOSPC; + goto out; + } + + init_iommu_device_fields(iommu_dev); iommu_dev->id = mem_mgr->num_devices; mem_mgr->devices[mem_mgr->num_devices++] = iommu_dev; - return 0; +out: + mutex_unlock(&mem_mgr->process_assignment_lock); + return ret; } /** @@ -52,14 +278,16 @@ void qda_memory_manager_unregister_device(struct qda_memory_manager *mem_mgr, { int i; + mutex_lock(&mem_mgr->process_assignment_lock); for (i = 0; i < mem_mgr->num_devices; i++) { if (mem_mgr->devices[i] == iommu_dev) { mem_mgr->devices[i] = NULL; break; } } + mutex_unlock(&mem_mgr->process_assignment_lock); - kfree(iommu_dev); + kref_put(&iommu_dev->ref, iommu_device_free); } /** @@ -80,6 +308,7 @@ int qda_memory_manager_init(struct qda_memory_manager *mem_mgr, int max_devices) mem_mgr->num_devices = 0; mem_mgr->max_devices = max_devices; + mutex_init(&mem_mgr->process_assignment_lock); return 0; } diff --git a/drivers/accel/qda/qda_memory_manager.h b/drivers/accel/qda/qda_memory_manager.h index 7e38c8a18284..0949c0c213f6 100644 --- a/drivers/accel/qda/qda_memory_manager.h +++ b/drivers/accel/qda/qda_memory_manager.h @@ -7,25 +7,44 @@ #define __QDA_MEMORY_MANAGER_H__ #include <linux/device.h> +#include <linux/kref.h> +#include <linux/mutex.h> +#include <linux/refcount.h> +#include <linux/spinlock.h> +#include <drm/drm_file.h> /* Forward declarations */ struct qda_dev; +struct qda_gem_obj; /** * struct qda_iommu_device - IOMMU device instance for memory management * * Represents a single IOMMU-enabled device managed by the memory manager. * Each device can be assigned to a specific process session. + * + * The object outlives its registration: open files keep a reference through + * @ref, so a device can be unregistered while a process still holds it. */ struct qda_iommu_device { /** @dev: Pointer to the underlying device */ struct device *dev; /** @qdev: Back-pointer to the parent QDA device */ struct qda_dev *qdev; + /** @assigned_file_priv: DRM file private data for the assigned process */ + struct drm_file *assigned_file_priv; /** @id: Unique identifier assigned by the memory manager */ u32 id; /** @sid: Stream ID for IOMMU transactions */ u32 sid; + /** @assigned_pid: Process ID of the process assigned to this device */ + pid_t assigned_pid; + /** @users: Number of open files sharing this device */ + refcount_t users; + /** @ref: Reference count controlling when the object is freed */ + struct kref ref; + /** @lock: Spinlock protecting concurrent access to device */ + spinlock_t lock; }; /** @@ -42,6 +61,8 @@ struct qda_memory_manager { int num_devices; /** @max_devices: Capacity of the @devices array */ int max_devices; + /** @process_assignment_lock: Mutex protecting process-to-device assignments */ + struct mutex process_assignment_lock; }; int qda_memory_manager_init(struct qda_memory_manager *mem_mgr, int max_devices); @@ -51,5 +72,14 @@ int qda_memory_manager_register_device(struct qda_memory_manager *mem_mgr, struct qda_iommu_device *iommu_dev); void qda_memory_manager_unregister_device(struct qda_memory_manager *mem_mgr, struct qda_iommu_device *iommu_dev); +int qda_memory_manager_assign_device(struct qda_memory_manager *mem_mgr, + struct drm_file *file_priv); +void qda_memory_manager_release_device(struct qda_iommu_device *iommu_dev); + +int qda_memory_manager_alloc(struct qda_memory_manager *mem_mgr, + struct qda_gem_obj *gem_obj, + struct drm_file *file_priv); +void qda_memory_manager_free(struct qda_memory_manager *mem_mgr, + struct qda_gem_obj *gem_obj); #endif /* __QDA_MEMORY_MANAGER_H__ */ -- 2.34.1