On 8/24/26 17:07, Rob Clark wrote:
On Mon, Aug 24, 2026 at 7:31 AM Christian König christian.koenig@amd.com wrote:
On 8/17/26 06:47, Ekansh Gupta wrote:
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.
Oh, stuff like that is usually a pretty big NO-GO now.
AMD has made the same mistake with KFD and it resulted in a massive chaos.
The DRM file is the driver context your process uses and even if there are multiple DRM files for the same PID you should absolute *NOT* share anything between them.
The general rule of thumb is to not attach anything to the process using the DRM file descriptor.
A couple other things to keep in mind:
- drm device fd can be passed across processes
- virtgpu/virglrenderer drm native ctx is a single process that opens
the drm device file N times on behalf of N guest userspace processes.
All that to say, Christian is right here.. drm_file is your context, pgtables should be attached to the drm_file (potentially via drm_gpuvm.. which you perhaps want to use).
Some additional points you should probably keep in mind:
1. In some configurations the DRM fd is not opened by the application but rather by the display server. So you see for example X/XWayland opening the fd.
2. For gdb plugins you now seriously want to use pidfd_getfd() to grab the DRM fd from the debugged process into your debugger process.
Hacks with the PID or TGID are something which needs in deep review for correctness.
Regards, Christian.
BR, -R
Regards, Christian.
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 ekansh.gupta@oss.qualcomm.com
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.odiff --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__ */
linaro-mm-sig@lists.linaro.org
-
Christian König