On Tue, May 19, 2026 at 11:45:57AM +0530, Ekansh Gupta via B4 Relay wrote: > From: Ekansh Gupta <[email protected]> > > Introduce the QDA memory manager (qda_memory_manager) to track and > manage the IOMMU devices that back each compute context bank (CB). > > Each CB device registered on the qda-compute-cb bus is assigned a > unique ID via an XArray and wrapped in a qda_iommu_device descriptor
Why do you need an XArray? The number of devices is (more or less) fixed. You can use a normal array, allocated in the probe function after counting OF children nodes. > that records the device pointer and its stream ID. This registry > allows the driver to look up the correct IOMMU domain for a given > session when mapping DSP buffers. > > The memory manager is initialised in qda_init_device() before CB > devices are populated and torn down in qda_deinit_device() after they > are destroyed, ensuring no dangling references remain in the XArray. > > qda_cb.c is extended with qda_cb_setup_device(), which is called > immediately after a CB device is registered on the bus. It allocates > a qda_iommu_device, registers it with the memory manager, and stores > it as the CB device's driver data so that qda_destroy_cb_device() can > retrieve and unregister it during teardown. > > Assisted-by: Claude:claude-4-6-sonnet > Signed-off-by: Ekansh Gupta <[email protected]> > --- > drivers/accel/qda/Makefile | 1 + > drivers/accel/qda/qda_cb.c | 47 ++++++++++++++ > drivers/accel/qda/qda_drv.c | 34 ++++++++++ > drivers/accel/qda/qda_drv.h | 5 ++ > drivers/accel/qda/qda_memory_manager.c | 111 > +++++++++++++++++++++++++++++++++ > drivers/accel/qda/qda_memory_manager.h | 49 +++++++++++++++ > drivers/accel/qda/qda_rpmsg.c | 7 +++ > 7 files changed, 254 insertions(+) > > diff --git a/drivers/accel/qda/Makefile b/drivers/accel/qda/Makefile > index 143c9e4e789e..701fad5ffb50 100644 > --- a/drivers/accel/qda/Makefile > +++ b/drivers/accel/qda/Makefile > @@ -8,6 +8,7 @@ obj-$(CONFIG_DRM_ACCEL_QDA) := qda.o > qda-y := \ > qda_cb.o \ > qda_drv.o \ > + qda_memory_manager.o \ > qda_rpmsg.o > > obj-$(CONFIG_DRM_ACCEL_QDA_COMPUTE_BUS) += qda_compute_bus.o > diff --git a/drivers/accel/qda/qda_cb.c b/drivers/accel/qda/qda_cb.c > index 77caf8438c67..6d540bb0ec7b 100644 > --- a/drivers/accel/qda/qda_cb.c > +++ b/drivers/accel/qda/qda_cb.c > @@ -8,11 +8,42 @@ > #include <linux/slab.h> > #include <drm/drm_print.h> > #include "qda_drv.h" > +#include "qda_memory_manager.h" > #include "qda_cb.h" > > +static int qda_cb_setup_device(struct qda_dev *qdev, struct device *cb_dev, > u32 sid) > +{ > + struct qda_iommu_device *iommu_dev; > + int rc; > + > + drm_dbg_driver(&qdev->drm_dev, "Setting up CB device %s\n", > dev_name(cb_dev)); > + > + iommu_dev = kzalloc_obj(*iommu_dev); > + if (!iommu_dev) > + return -ENOMEM; > + > + iommu_dev->dev = cb_dev; > + iommu_dev->qdev = qdev; > + iommu_dev->sid = sid; > + > + rc = qda_memory_manager_register_device(qdev->iommu_mgr, iommu_dev); > + if (rc) { > + drm_err(&qdev->drm_dev, "Failed to register IOMMU device: > %d\n", rc); > + kfree(iommu_dev); > + return rc; > + } > + > + dev_set_drvdata(cb_dev, iommu_dev); > + > + drm_dbg_driver(&qdev->drm_dev, "CB device setup complete - SID: %u\n", > sid); > + > + return 0; > +} > + > int qda_create_cb_device(struct qda_dev *qdev, struct device_node *cb_node) > { > struct device *cb_dev; > + int ret; > u32 sid = 0; > char name[64]; > struct qda_cb_dev *entry; > @@ -30,6 +61,13 @@ int qda_create_cb_device(struct qda_dev *qdev, struct > device_node *cb_node) > return PTR_ERR(cb_dev); > } > > + ret = qda_cb_setup_device(qdev, cb_dev, sid); > + if (ret) { > + drm_err(&qdev->drm_dev, "CB device setup failed: %d\n", ret); > + device_unregister(cb_dev); > + return ret; > + } > + > entry = kzalloc_obj(*entry); > if (!entry) { > device_unregister(cb_dev); > @@ -80,6 +118,7 @@ int qda_cb_populate(struct qda_dev *qdev, struct > device_node *parent_node) > void qda_destroy_cb_device(struct device *cb_dev) > { > struct iommu_group *group; > + struct qda_iommu_device *iommu_dev; > > if (!cb_dev) { > pr_debug("qda: NULL CB device passed to destroy\n"); > @@ -88,6 +127,14 @@ void qda_destroy_cb_device(struct device *cb_dev) > > dev_dbg(cb_dev, "Destroying CB device %s\n", dev_name(cb_dev)); > > + iommu_dev = dev_get_drvdata(cb_dev); > + if (iommu_dev && iommu_dev->qdev && iommu_dev->qdev->iommu_mgr) { > + dev_dbg(cb_dev, "Unregistering IOMMU device for %s\n", > + dev_name(cb_dev)); > + qda_memory_manager_unregister_device(iommu_dev->qdev->iommu_mgr, > + iommu_dev); > + } > + > group = iommu_group_get(cb_dev); > if (group) { > dev_dbg(cb_dev, "Removing %s from IOMMU group\n", > dev_name(cb_dev)); > diff --git a/drivers/accel/qda/qda_drv.c b/drivers/accel/qda/qda_drv.c > index 6c20d6a2fc47..0ad5d9873d7e 100644 > --- a/drivers/accel/qda/qda_drv.c > +++ b/drivers/accel/qda/qda_drv.c > @@ -57,6 +57,40 @@ struct qda_dev *qda_alloc_device(struct device *dev) > return qdev; > } > > +static void cleanup_memory_manager(struct qda_dev *qdev) Prefixes... > +{ > + if (qdev->iommu_mgr) { > + qda_memory_manager_exit(qdev->iommu_mgr); > + kfree(qdev->iommu_mgr); > + qdev->iommu_mgr = NULL; > + } > +} > + > +static int init_memory_manager(struct qda_dev *qdev) > +{ > + qdev->iommu_mgr = kzalloc_obj(*qdev->iommu_mgr); > + if (!qdev->iommu_mgr) > + return -ENOMEM; > + > + return qda_memory_manager_init(qdev->iommu_mgr); > +} > + > +void qda_deinit_device(struct qda_dev *qdev) > +{ > + cleanup_memory_manager(qdev); Ugh, inline all your one-line wrappers. > +} > + > +int qda_init_device(struct qda_dev *qdev) > +{ > + int ret; > + > + ret = init_memory_manager(qdev); > + if (ret) > + drm_err(&qdev->drm_dev, "Failed to initialize memory manager: > %d\n", ret); > + > + return ret; > +} > + > void qda_unregister_device(struct qda_dev *qdev) > { > drm_dev_unregister(&qdev->drm_dev); > diff --git a/drivers/accel/qda/qda_drv.h b/drivers/accel/qda/qda_drv.h > index 2715f378775d..eb089e586b17 100644 > --- a/drivers/accel/qda/qda_drv.h > +++ b/drivers/accel/qda/qda_drv.h > @@ -13,6 +13,7 @@ > #include <drm/drm_device.h> > #include <drm/drm_drv.h> > #include <drm/drm_file.h> > +#include "qda_memory_manager.h" > > /* Driver identification */ > #define QDA_DRIVER_NAME "qda" > @@ -40,6 +41,8 @@ struct qda_dev { > struct device *dev; > /** @cb_devs: Compute context-bank (CB) child devices */ > struct list_head cb_devs; > + /** @iommu_mgr: IOMMU/memory manager instance */ > + struct qda_memory_manager *iommu_mgr; > /** @dsp_name: Name of the DSP domain (e.g. "cdsp", "adsp") */ > const char *dsp_name; > }; > @@ -59,6 +62,8 @@ static inline struct qda_dev *qda_dev_from_drm(struct > drm_device *dev) > struct qda_dev *qda_alloc_device(struct device *dev); > > /* Core device lifecycle */ > +int qda_init_device(struct qda_dev *qdev); > +void qda_deinit_device(struct qda_dev *qdev); > int qda_register_device(struct qda_dev *qdev); > void qda_unregister_device(struct qda_dev *qdev); > > diff --git a/drivers/accel/qda/qda_memory_manager.c > b/drivers/accel/qda/qda_memory_manager.c > new file mode 100644 > index 000000000000..00a9c0ae4224 > --- /dev/null > +++ b/drivers/accel/qda/qda_memory_manager.c > @@ -0,0 +1,111 @@ > +// 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 <linux/xarray.h> > +#include <drm/drm_file.h> > +#include "qda_drv.h" > +#include "qda_memory_manager.h" > + > +static void cleanup_all_memory_devices(struct qda_memory_manager *mem_mgr) > +{ > + unsigned long index; > + void *entry; > + > + pr_debug("qda: Starting cleanup of all memory devices\n"); pr_debug is a third way to debug. Stop it, please. > + > + xa_for_each(&mem_mgr->device_xa, index, entry) { > + struct qda_iommu_device *iommu_dev = entry; > + > + pr_debug("qda: Cleaning up device id=%lu\n", index); > + > + xa_erase(&mem_mgr->device_xa, index); > + kfree(iommu_dev); > + } > + > + pr_debug("qda: Completed cleanup of all memory devices\n"); > +} > + -- With best wishes Dmitry
