This uses the SHMEM DRM helpers and we map right away to the CPU and NPU
sides, as all buffers are expected to be accessed from both.
v2:
- Sync the IOMMUs for the other cores when mapping and unmapping.
v3:
- Make use of GPL-2.0-only for the copyright notice (Jeff Hugo)
v6:
- Use mutexes guard (Markus Elfring)
v7:
- Assign its own IOMMU domain to each client, for isolation (Daniel
Stone and Robin Murphy)
v8:
- Correctly acquire a reference to the IOMMU (Robin Murphy)
- Allocate DMA address ourselves with drm_mm (Robin Murphy)
- Use refcount_read (Heiko Stuebner)
- Remove superfluous dma_sync_sgtable_for_device (Robin Murphy)
Reviewed-by: Jeffrey Hugo <quic_jh...@quicinc.com>
Tested-by: Heiko Stuebner <he...@sntech.de>
Signed-off-by: Tomeu Vizoso <to...@tomeuvizoso.net>
---
drivers/accel/rocket/Makefile | 3 +-
drivers/accel/rocket/rocket_drv.c | 15 ++++-
drivers/accel/rocket/rocket_drv.h | 4 ++
drivers/accel/rocket/rocket_gem.c | 125 ++++++++++++++++++++++++++++++++++++++
drivers/accel/rocket/rocket_gem.h | 30 +++++++++
include/uapi/drm/rocket_accel.h | 44 ++++++++++++++
6 files changed, 219 insertions(+), 2 deletions(-)
diff --git a/drivers/accel/rocket/Makefile b/drivers/accel/rocket/Makefile
index
abdd75f2492eaecf8bf5e78a2ac150ea19ac3e96..4deef267f9e1238c4d8bd108dcc8afd9dc8b2b8f
100644
--- a/drivers/accel/rocket/Makefile
+++ b/drivers/accel/rocket/Makefile
@@ -5,4 +5,5 @@ obj-$(CONFIG_DRM_ACCEL_ROCKET) := rocket.o
rocket-y := \
rocket_core.o \
rocket_device.o \
- rocket_drv.o
+ rocket_drv.o \
+ rocket_gem.o
diff --git a/drivers/accel/rocket/rocket_drv.c
b/drivers/accel/rocket/rocket_drv.c
index
a5df94f6b1259ae335fbccd0105ba44f3432999c..8b7fbe9226f424b69d409e47b58651cba8c42bcf
100644
--- a/drivers/accel/rocket/rocket_drv.c
+++ b/drivers/accel/rocket/rocket_drv.c
@@ -5,6 +5,7 @@
#include <drm/drm_drv.h>
#include <drm/drm_gem.h>
#include <drm/drm_ioctl.h>
+#include <drm/rocket_accel.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/iommu.h>
@@ -13,6 +14,7 @@
#include <linux/pm_runtime.h>
#include "rocket_drv.h"
+#include "rocket_gem.h"
/*
* Facade device, used to expose a single DRM device to userspace, that
@@ -69,6 +71,7 @@ rocket_open(struct drm_device *dev, struct drm_file *file)
{
struct rocket_device *rdev = to_rocket_device(dev);
struct rocket_file_priv *rocket_priv;
+ u64 start, end;
int ret;
if (!try_module_get(THIS_MODULE))
@@ -89,6 +92,11 @@ rocket_open(struct drm_device *dev, struct drm_file *file)
file->driver_priv = rocket_priv;
+ start = rocket_priv->domain->domain->geometry.aperture_start;
+ end = rocket_priv->domain->domain->geometry.aperture_end;
+ drm_mm_init(&rocket_priv->mm, start, end - start + 1);
+ mutex_init(&rocket_priv->mm_lock);
+
return 0;
err_free:
@@ -103,6 +111,8 @@ rocket_postclose(struct drm_device *dev, struct drm_file
*file)
{
struct rocket_file_priv *rocket_priv = file->driver_priv;
+ mutex_destroy(&rocket_priv->mm_lock);
+ drm_mm_takedown(&rocket_priv->mm);
rocket_iommu_domain_put(rocket_priv->domain);
kfree(rocket_priv);
module_put(THIS_MODULE);
@@ -111,6 +121,8 @@ rocket_postclose(struct drm_device *dev, struct drm_file
*file)
static const struct drm_ioctl_desc rocket_drm_driver_ioctls[] = {
#define ROCKET_IOCTL(n, func) \
DRM_IOCTL_DEF_DRV(ROCKET_##n, rocket_ioctl_##func, 0)
+
+ ROCKET_IOCTL(CREATE_BO, create_bo),
};
DEFINE_DRM_ACCEL_FOPS(rocket_accel_driver_fops);
@@ -120,9 +132,10 @@ DEFINE_DRM_ACCEL_FOPS(rocket_accel_driver_fops);
* - 1.0 - initial interface
*/
static const struct drm_driver rocket_drm_driver = {
- .driver_features = DRIVER_COMPUTE_ACCEL,
+ .driver_features = DRIVER_COMPUTE_ACCEL | DRIVER_GEM,
.open = rocket_open,
.postclose = rocket_postclose,
+ .gem_create_object = rocket_gem_create_object,
.ioctls = rocket_drm_driver_ioctls,
.num_ioctls = ARRAY_SIZE(rocket_drm_driver_ioctls),
.fops = &rocket_accel_driver_fops,
diff --git a/drivers/accel/rocket/rocket_drv.h
b/drivers/accel/rocket/rocket_drv.h
index
36b1291b0ead388b8843965758c57a0405315519..2944e0136ab991da61fb8f66f7e9c1ba214878a6
100644
--- a/drivers/accel/rocket/rocket_drv.h
+++ b/drivers/accel/rocket/rocket_drv.h
@@ -4,6 +4,8 @@
#ifndef __ROCKET_DRV_H__
#define __ROCKET_DRV_H__
+#include <drm/drm_mm.h>
+
#include "rocket_device.h"
struct rocket_iommu_domain {
@@ -15,6 +17,8 @@ struct rocket_file_priv {
struct rocket_device *rdev;
struct rocket_iommu_domain *domain;
+ struct drm_mm mm;
+ struct mutex mm_lock;
};
struct rocket_iommu_domain *rocket_iommu_domain_get(struct rocket_file_priv
*rocket_priv);
diff --git a/drivers/accel/rocket/rocket_gem.c
b/drivers/accel/rocket/rocket_gem.c
new file mode 100644
index
0000000000000000000000000000000000000000..05cf46040865c01fe14a169c865227780f2db679
--- /dev/null
+++ b/drivers/accel/rocket/rocket_gem.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright 2024-2025 Tomeu Vizoso <to...@tomeuvizoso.net> */
+
+#include <drm/drm_device.h>
+#include <drm/drm_utils.h>
+#include <drm/rocket_accel.h>
+#include <linux/dma-mapping.h>
+#include <linux/iommu.h>
+
+#include "rocket_drv.h"
+#include "rocket_gem.h"
+
+static void rocket_gem_bo_free(struct drm_gem_object *obj)
+{
+ struct rocket_gem_object *bo = to_rocket_bo(obj);
+ struct rocket_file_priv *rocket_priv = bo->driver_priv;
+ size_t unmapped;
+
+ drm_WARN_ON(obj->dev, refcount_read(&bo->base.pages_use_count) > 1);
+
+ unmapped = iommu_unmap(bo->domain->domain, bo->mm.start, bo->size);
+ drm_WARN_ON(obj->dev, unmapped != bo->size);
+
+ mutex_lock(&rocket_priv->mm_lock);
+ drm_mm_remove_node(&bo->mm);
+ mutex_unlock(&rocket_priv->mm_lock);
+
+ rocket_iommu_domain_put(bo->domain);
+ bo->domain = NULL;
+
+ drm_gem_shmem_free(&bo->base);
+}
+
+static const struct drm_gem_object_funcs rocket_gem_funcs = {
+ .free = rocket_gem_bo_free,
+ .print_info = drm_gem_shmem_object_print_info,
+ .pin = drm_gem_shmem_object_pin,
+ .unpin = drm_gem_shmem_object_unpin,
+ .get_sg_table = drm_gem_shmem_object_get_sg_table,
+ .vmap = drm_gem_shmem_object_vmap,
+ .vunmap = drm_gem_shmem_object_vunmap,
+ .mmap = drm_gem_shmem_object_mmap,
+ .vm_ops = &drm_gem_shmem_vm_ops,
+};
+
+struct drm_gem_object *rocket_gem_create_object(struct drm_device *dev, size_t
size)
+{
+ struct rocket_gem_object *obj;
+
+ obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+ if (!obj)
+ return ERR_PTR(-ENOMEM);
+
+ obj->base.base.funcs = &rocket_gem_funcs;
+
+ return &obj->base.base;
+}
+
+int rocket_ioctl_create_bo(struct drm_device *dev, void *data, struct drm_file
*file)
+{
+ struct rocket_file_priv *rocket_priv = file->driver_priv;
+ struct drm_rocket_create_bo *args = data;
+ struct drm_gem_shmem_object *shmem_obj;
+ struct rocket_gem_object *rkt_obj;
+ struct drm_gem_object *gem_obj;
+ struct sg_table *sgt;
+ int ret;
+
+ shmem_obj = drm_gem_shmem_create(dev, args->size);
+ if (IS_ERR(shmem_obj))
+ return PTR_ERR(shmem_obj);
+
+ gem_obj = &shmem_obj->base;
+ rkt_obj = to_rocket_bo(gem_obj);
+
+ rkt_obj->driver_priv = rocket_priv;
+ rkt_obj->domain = rocket_iommu_domain_get(rocket_priv);
+ rkt_obj->size = args->size;
+ rkt_obj->offset = 0;
+
+ ret = drm_gem_handle_create(file, gem_obj, &args->handle);
+ drm_gem_object_put(gem_obj);
+ if (ret)
+ goto err;
+
+ sgt = drm_gem_shmem_get_pages_sgt(shmem_obj);
+ if (IS_ERR(sgt)) {
+ ret = PTR_ERR(sgt);
+ goto err;
+ }
+
+ mutex_lock(&rocket_priv->mm_lock);
+ ret = drm_mm_insert_node_generic(&rocket_priv->mm, &rkt_obj->mm,
+ rkt_obj->size, PAGE_SIZE,
+ 0, 0);
+ mutex_unlock(&rocket_priv->mm_lock);
+
+ ret = iommu_map_sgtable(rocket_priv->domain->domain,
+ rkt_obj->mm.start,
+ shmem_obj->sgt,
+ IOMMU_READ | IOMMU_WRITE);
+ if (ret < 0 || ret < args->size) {
+ drm_err(dev, "failed to map buffer: size=%d request_size=%u\n",
+ ret, args->size);
+ ret = -ENOMEM;
+ goto err_remove_node;
+ }
+
+ /* iommu_map_sgtable might have aligned the size */
+ rkt_obj->size = ret;
+ args->offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
+ args->dma_address = rkt_obj->mm.start;
+
+ return 0;
+
+err_remove_node:
+ mutex_lock(&rocket_priv->mm_lock);
+ drm_mm_remove_node(&rkt_obj->mm);
+ mutex_unlock(&rocket_priv->mm_lock);
+
+err:
+ drm_gem_shmem_object_free(gem_obj);
+
+ return ret;
+}
diff --git a/drivers/accel/rocket/rocket_gem.h
b/drivers/accel/rocket/rocket_gem.h
new file mode 100644
index
0000000000000000000000000000000000000000..91a1fc09c56ce483ebe80959e1a7ff934867bedc
--- /dev/null
+++ b/drivers/accel/rocket/rocket_gem.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright 2024-2025 Tomeu Vizoso <to...@tomeuvizoso.net> */
+
+#ifndef __ROCKET_GEM_H__
+#define __ROCKET_GEM_H__
+
+#include <drm/drm_gem_shmem_helper.h>
+
+struct rocket_gem_object {
+ struct drm_gem_shmem_object base;
+
+ struct rocket_file_priv *driver_priv;
+
+ struct rocket_iommu_domain *domain;
+ struct drm_mm_node mm;
+ size_t size;
+ u32 offset;
+};
+
+struct drm_gem_object *rocket_gem_create_object(struct drm_device *dev, size_t
size);
+
+int rocket_ioctl_create_bo(struct drm_device *dev, void *data, struct drm_file
*file);
+
+static inline
+struct rocket_gem_object *to_rocket_bo(struct drm_gem_object *obj)
+{
+ return container_of(to_drm_gem_shmem_obj(obj), struct
rocket_gem_object, base);
+}
+
+#endif
diff --git a/include/uapi/drm/rocket_accel.h b/include/uapi/drm/rocket_accel.h
new file mode 100644
index
0000000000000000000000000000000000000000..95720702b7c4413d72b89c1f0f59abb22dc8c6b3
--- /dev/null
+++ b/include/uapi/drm/rocket_accel.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2024 Tomeu Vizoso
+ */
+#ifndef __DRM_UAPI_ROCKET_ACCEL_H__
+#define __DRM_UAPI_ROCKET_ACCEL_H__
+
+#include "drm.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+#define DRM_ROCKET_CREATE_BO 0x00
+
+#define DRM_IOCTL_ROCKET_CREATE_BO DRM_IOWR(DRM_COMMAND_BASE +
DRM_ROCKET_CREATE_BO, struct drm_rocket_create_bo)
+
+/**
+ * struct drm_rocket_create_bo - ioctl argument for creating Rocket BOs.
+ *
+ */
+struct drm_rocket_create_bo {
+ /** Input: Size of the requested BO. */
+ __u32 size;
+
+ /** Output: GEM handle for the BO. */
+ __u32 handle;
+
+ /**
+ * Output: DMA address for the BO in the NPU address space. This
address
+ * is private to the DRM fd and is valid for the lifetime of the GEM
+ * handle.
+ */
+ __u64 dma_address;
+
+ /** Output: Offset into the drm node to use for subsequent mmap call. */
+ __u64 offset;
+};
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __DRM_UAPI_ROCKET_ACCEL_H__ */
--
2.50.0
