On Tue, Feb 24, 2026 at 12:39:02AM +0530, Ekansh Gupta wrote: > Introduce per-file and per-user context for the QDA DRM accelerator > driver. A new qda_file_priv structure is stored in file->driver_priv > for each open file descriptor, and a qda_user object is allocated per > client with a unique client_id generated from an atomic counter in > qda_dev. > > The DRM driver now provides qda_open() and qda_postclose() callbacks. > qda_open() resolves the qda_dev from the drm_device, allocates the > qda_file_priv and qda_user structures, and attaches them to the DRM > file. qda_postclose() tears down the per-file context and frees the > qda_user object when the file is closed. > > This prepares the QDA driver to track per-process state for future > features such as per-client memory mappings, job submission contexts, > and access control over DSP compute resources.
Start by describing the problem instead of stuffing it to the end. Can we use something better suited for this task, like IDR? > Signed-off-by: Ekansh Gupta <[email protected]> > --- > drivers/accel/qda/qda_drv.c | 117 > ++++++++++++++++++++++++++++++++++++++++++++ > drivers/accel/qda/qda_drv.h | 30 ++++++++++++ > 2 files changed, 147 insertions(+) > > diff --git a/drivers/accel/qda/qda_drv.c b/drivers/accel/qda/qda_drv.c > index a9113ec78fa2..bf95fc782cf8 100644 > --- a/drivers/accel/qda/qda_drv.c > +++ b/drivers/accel/qda/qda_drv.c > @@ -12,11 +12,127 @@ > #include "qda_drv.h" > #include "qda_rpmsg.h" > > +static struct qda_drm_priv *get_drm_priv_from_device(struct drm_device *dev) > +{ > + if (!dev) > + return NULL; > + > + return (struct qda_drm_priv *)dev->dev_private; > +} > + > +static struct qda_dev *get_qdev_from_drm_device(struct drm_device *dev) > +{ > + struct qda_drm_priv *drm_priv; > + > + if (!dev) { > + qda_dbg(NULL, "Invalid drm_device\n"); > + return NULL; > + } > + > + drm_priv = get_drm_priv_from_device(dev); > + if (!drm_priv) { > + qda_dbg(NULL, "No drm_priv in dev_private\n"); > + return NULL; > + } > + > + return drm_priv->qdev; > +} > + > +static struct qda_user *alloc_qda_user(struct qda_dev *qdev) > +{ > + struct qda_user *qda_user; > + > + qda_user = kzalloc_obj(*qda_user, GFP_KERNEL); > + if (!qda_user) > + return NULL; > + > + qda_user->client_id = atomic_inc_return(&qdev->client_id_counter); > + qda_user->qda_dev = qdev; > + > + qda_dbg(qdev, "Allocated qda_user with client_id=%u\n", > qda_user->client_id); > + return qda_user; > +} > + > +static void free_qda_user(struct qda_user *qda_user) > +{ > + if (!qda_user) > + return; > + > + qda_dbg(qda_user->qda_dev, "Freeing qda_user client_id=%u\n", > qda_user->client_id); > + > + kfree(qda_user); > +} > + > +static int qda_open(struct drm_device *dev, struct drm_file *file) > +{ > + struct qda_user *qda_user; > + struct qda_file_priv *qda_file_priv; > + struct qda_dev *qdev; > + > + if (!file) { > + qda_dbg(NULL, "Invalid file pointer\n"); > + return -EINVAL; > + } > + > + qdev = get_qdev_from_drm_device(dev); > + if (!qdev) { > + qda_dbg(NULL, "Failed to get qdev from drm_device\n"); > + return -EINVAL; > + } > + > + qda_file_priv = kzalloc(sizeof(*qda_file_priv), GFP_KERNEL); > + if (!qda_file_priv) > + return -ENOMEM; > + > + qda_file_priv->pid = current->pid; > + > + qda_user = alloc_qda_user(qdev); > + if (!qda_user) { > + qda_dbg(qdev, "Failed to allocate qda_user\n"); > + kfree(qda_file_priv); > + return -ENOMEM; > + } > + > + file->driver_priv = qda_file_priv; > + qda_file_priv->qda_user = qda_user; > + > + qda_dbg(qdev, "Device opened successfully for PID %d\n", current->pid); > + > + return 0; > +} > + > +static void qda_postclose(struct drm_device *dev, struct drm_file *file) > +{ > + struct qda_dev *qdev; > + struct qda_file_priv *qda_file_priv; > + struct qda_user *qda_user; > + > + qdev = get_qdev_from_drm_device(dev); > + if (!qdev || atomic_read(&qdev->removing)) { > + qda_dbg(NULL, "Device unavailable or removing\n"); > + return; Even if it is being removed, no need to free the memory? > + } > + > + qda_file_priv = (struct qda_file_priv *)file->driver_priv; > + if (qda_file_priv) { > + qda_user = qda_file_priv->qda_user; > + if (qda_user) > + free_qda_user(qda_user); > + > + kfree(qda_file_priv); > + file->driver_priv = NULL; > + } > + > + qda_dbg(qdev, "Device closed for PID %d\n", current->pid); > +} > + > DEFINE_DRM_ACCEL_FOPS(qda_accel_fops); > > static struct drm_driver qda_drm_driver = { > .driver_features = DRIVER_COMPUTE_ACCEL, > .fops = &qda_accel_fops, > + .open = qda_open, > + .postclose = qda_postclose, > .name = DRIVER_NAME, > .desc = "Qualcomm DSP Accelerator Driver", > }; > @@ -58,6 +174,7 @@ static void init_device_resources(struct qda_dev *qdev) > > mutex_init(&qdev->lock); > atomic_set(&qdev->removing, 0); > + atomic_set(&qdev->client_id_counter, 0); > } > > static int init_memory_manager(struct qda_dev *qdev) > diff --git a/drivers/accel/qda/qda_drv.h b/drivers/accel/qda/qda_drv.h > index 2b80401a3741..e0ba37702a86 100644 > --- a/drivers/accel/qda/qda_drv.h > +++ b/drivers/accel/qda/qda_drv.h > @@ -10,6 +10,7 @@ > #include <linux/list.h> > #include <linux/mutex.h> > #include <linux/rpmsg.h> > +#include <linux/types.h> > #include <linux/xarray.h> > #include <drm/drm_drv.h> > #include <drm/drm_file.h> > @@ -20,6 +21,33 @@ > /* Driver identification */ > #define DRIVER_NAME "qda" > > +/** > + * struct qda_file_priv - Per-process private data for DRM file > + * > + * This structure tracks per-process state for each open file descriptor. > + * It maintains the IOMMU device assignment and links to the legacy qda_user > + * structure for compatibility with existing code. > + */ > +struct qda_file_priv { > + /* Process ID for tracking */ > + pid_t pid; > + /* Pointer to qda_user structure for backward compatibility */ > + struct qda_user *qda_user; > +}; > + > +/** > + * struct qda_user - Per-user context for remote processor interaction > + * > + * This structure maintains per-user state for interactions with the > + * remote processor, including memory mappings and pending operations. > + */ > +struct qda_user { > + /* Unique client identifier */ > + u32 client_id; > + /* Back-pointer to device structure */ > + struct qda_dev *qda_dev; > +}; > + > /** > * struct qda_drm_priv - DRM device private data for QDA device > * > @@ -52,6 +80,8 @@ struct qda_dev { > struct qda_drm_priv *drm_priv; > /* Flag indicating device removal in progress */ > atomic_t removing; > + /* Atomic counter for generating unique client IDs */ > + atomic_t client_id_counter; > /* Name of the DSP (e.g., "cdsp", "adsp") */ > char dsp_name[16]; > /* Compute context-bank (CB) child devices */ > > -- > 2.34.1 > -- With best wishes Dmitry
