Message-Id: <20250520-6-10-rocket-v5-6-18c9ca0fcb3c@tomeuvizoso.net>
Date: Tue, 20 May 2025 12:26:59 +0200
From: Tomeu Vizoso <tomeu@...euvizoso.net>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Heiko Stuebner <heiko@...ech.de>, 
 Oded Gabbay <ogabbay@...nel.org>, Jonathan Corbet <corbet@....net>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Sumit Semwal <sumit.semwal@...aro.org>, 
 Christian König <christian.koenig@....com>, 
 Sebastian Reichel <sebastian.reichel@...labora.com>, 
 Nicolas Frattaroli <nicolas.frattaroli@...labora.com>, 
 Jeff Hugo <jeff.hugo@....qualcomm.com>
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 dri-devel@...ts.freedesktop.org, linux-doc@...r.kernel.org, 
 linux-media@...r.kernel.org, linaro-mm-sig@...ts.linaro.org, 
 Tomeu Vizoso <tomeu@...euvizoso.net>
Subject: [PATCH v5 06/10] accel/rocket: Add IOCTL for BO creation

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)

Reviewed-by: Jeffrey Hugo <quic_jhugo@...cinc.com>
Signed-off-by: Tomeu Vizoso <tomeu@...euvizoso.net>
---
 drivers/accel/rocket/Makefile        |   3 +-
 drivers/accel/rocket/rocket_device.c |   4 ++
 drivers/accel/rocket/rocket_device.h |   2 +
 drivers/accel/rocket/rocket_drv.c    |   7 +-
 drivers/accel/rocket/rocket_gem.c    | 131 +++++++++++++++++++++++++++++++++++
 drivers/accel/rocket/rocket_gem.h    |  26 +++++++
 include/uapi/drm/rocket_accel.h      |  44 ++++++++++++
 7 files changed, 215 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_device.c b/drivers/accel/rocket/rocket_device.c
index 97e32d19a1b4a36177b8039b67b4892887daa880..ee81810dd171ef1cdb1582c1bbe5099c669e42cc 100644
--- a/drivers/accel/rocket/rocket_device.c
+++ b/drivers/accel/rocket/rocket_device.c
@@ -4,6 +4,7 @@
 #include <linux/array_size.h>
 #include <linux/clk.h>
 #include <linux/dev_printk.h>
+#include <linux/mutex.h>
 
 #include "rocket_device.h"
 
@@ -21,10 +22,13 @@ int rocket_device_init(struct rocket_device *rdev)
 	if (err)
 		return err;
 
+	mutex_init(&rdev->iommu_lock);
+
 	return 0;
 }
 
 void rocket_device_fini(struct rocket_device *rdev)
 {
+	mutex_destroy(&rdev->iommu_lock);
 	rocket_core_fini(&rdev->cores[0]);
 }
diff --git a/drivers/accel/rocket/rocket_device.h b/drivers/accel/rocket/rocket_device.h
index 55f4da252cfbd1f102c56e5009472deff59aaaec..2e22aa2b95252a2850a40c3271a91cb3aca578ae 100644
--- a/drivers/accel/rocket/rocket_device.h
+++ b/drivers/accel/rocket/rocket_device.h
@@ -14,6 +14,8 @@ struct rocket_device {
 
 	struct clk_bulk_data clks[2];
 
+	struct mutex iommu_lock;
+
 	struct rocket_core *cores;
 	unsigned int num_cores;
 };
diff --git a/drivers/accel/rocket/rocket_drv.c b/drivers/accel/rocket/rocket_drv.c
index d1a1be32760feed864db86963b9942f1e37b17eb..685499537a0a8a206452b745ff23f9ff170b35db 100644
--- a/drivers/accel/rocket/rocket_drv.c
+++ b/drivers/accel/rocket/rocket_drv.c
@@ -6,6 +6,7 @@
 #include <drm/drm_gem.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_of.h>
+#include <drm/rocket_accel.h>
 #include <linux/array_size.h>
 #include <linux/clk.h>
 #include <linux/component.h>
@@ -15,6 +16,7 @@
 #include <linux/pm_runtime.h>
 
 #include "rocket_drv.h"
+#include "rocket_gem.h"
 
 static int
 rocket_open(struct drm_device *dev, struct drm_file *file)
@@ -43,6 +45,8 @@ 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);
@@ -52,9 +56,10 @@ 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_gem.c b/drivers/accel/rocket/rocket_gem.c
new file mode 100644
index 0000000000000000000000000000000000000000..8a8a7185daac4740081293aae6945c9b2bbeb2dd
--- /dev/null
+++ b/drivers/accel/rocket/rocket_gem.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright 2024-2025 Tomeu Vizoso <tomeu@...euvizoso.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_device.h"
+#include "rocket_gem.h"
+
+static void rocket_gem_bo_free(struct drm_gem_object *obj)
+{
+	struct rocket_device *rdev = to_rocket_device(obj->dev);
+	struct rocket_gem_object *bo = to_rocket_bo(obj);
+	struct sg_table *sgt;
+
+	drm_WARN_ON(obj->dev, bo->base.pages_use_count > 1);
+
+	mutex_lock(&rdev->iommu_lock);
+
+	sgt = drm_gem_shmem_get_pages_sgt(&bo->base);
+
+	/* Unmap this object from the IOMMUs for cores > 0 */
+	for (unsigned int core = 1; core < rdev->num_cores; core++) {
+		struct iommu_domain *domain = iommu_get_domain_for_dev(rdev->cores[core].dev);
+		size_t unmapped = iommu_unmap(domain, sgt->sgl->dma_address, bo->size);
+
+		drm_WARN_ON(obj->dev, unmapped != bo->size);
+	}
+
+	/* This will unmap the pages from the IOMMU linked to core 0 */
+	drm_gem_shmem_free(&bo->base);
+
+	mutex_unlock(&rdev->iommu_lock);
+}
+
+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 drm_rocket_create_bo *args = data;
+	struct rocket_device *rdev = to_rocket_device(dev);
+	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->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;
+
+	mutex_lock(&rdev->iommu_lock);
+
+	/* This will map the pages to the IOMMU linked to core 0 */
+	sgt = drm_gem_shmem_get_pages_sgt(shmem_obj);
+	if (IS_ERR(sgt)) {
+		ret = PTR_ERR(sgt);
+		goto err_unlock;
+	}
+
+	/* Map the pages to the IOMMUs linked to the other cores, so all cores can access this BO */
+	for (unsigned int core = 1; core < rdev->num_cores; core++) {
+		ret = iommu_map_sgtable(iommu_get_domain_for_dev(rdev->cores[core].dev),
+					sgt->sgl->dma_address,
+					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_unlock;
+		}
+
+		/* iommu_map_sgtable might have aligned the size */
+		rkt_obj->size = ret;
+
+		dma_sync_sgtable_for_device(rdev->cores[core].dev, shmem_obj->sgt,
+					    DMA_BIDIRECTIONAL);
+	}
+
+	mutex_unlock(&rdev->iommu_lock);
+
+	args->offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
+	args->dma_address = sg_dma_address(shmem_obj->sgt->sgl);
+
+	return 0;
+
+err_unlock:
+	mutex_unlock(&rdev->iommu_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..41497554366961cfe18cf6c7e93ab1e4e5dc1886
--- /dev/null
+++ b/drivers/accel/rocket/rocket_gem.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright 2024-2025 Tomeu Vizoso <tomeu@...euvizoso.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;
+
+	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__ */

-- 
2.49.0

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