[RFC PATCH] drm/vgem: virtual GEM provider
Adam Jackson
ajax at redhat.com
Wed Jan 11 11:19:21 PST 2012
This is about as minimal of a virtual GEM service as possible. My plan
is to use this with non-native-3D hardware for buffer sharing between X
and DRI.
The current drisw winsys assumes an unmodified X server, which means
it's hopelessly inefficient for both the push direction of SwapBuffers/
DrawPixels and the pull direction of GLX_EXT_texture_from_pixmap. I'm
still working through the details of what the xserver support will look
like, but in broad strokes it's "use vgem for CreatePixmap and
optionally the shadowfb".
Obviously alpha quality, mostly looking for feedback on the approach or
any glaring bugs. Eventually I'd like to see solutions for sharing gem
objects between drm devices and/or the dma_buf API, but that's a ways
down the road.
Signed-off-by: Adam Jackson <ajax at redhat.com>
---
drivers/gpu/drm/Kconfig | 8 ++
drivers/gpu/drm/Makefile | 1 +
drivers/gpu/drm/vgem/Makefile | 4 +
drivers/gpu/drm/vgem/vgem_drv.c | 262 +++++++++++++++++++++++++++++++++++++++
include/drm/vgem_drm.h | 51 ++++++++
5 files changed, 326 insertions(+), 0 deletions(-)
create mode 100644 drivers/gpu/drm/vgem/Makefile
create mode 100644 drivers/gpu/drm/vgem/vgem_drv.c
create mode 100644 include/drm/vgem_drm.h
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 1368826..46322ba 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -159,6 +159,14 @@ config DRM_SAVAGE
Choose this option if you have a Savage3D/4/SuperSavage/Pro/Twister
chipset. If M is selected the module will be called savage.
+config DRM_VGEM
+ tristate "Virtual GEM provider"
+ depends on DRM
+ help
+ Choose this option to get a virtual graphics memory manager,
+ as used by Mesa's software renderer for enhanced performance.
+ If M is selected the module will be called vgem.
+
source "drivers/gpu/drm/exynos/Kconfig"
source "drivers/gpu/drm/vmwgfx/Kconfig"
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index c0496f6..132de0e 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_DRM_SIS) += sis/
obj-$(CONFIG_DRM_SAVAGE)+= savage/
obj-$(CONFIG_DRM_VMWGFX)+= vmwgfx/
obj-$(CONFIG_DRM_VIA) +=via/
+obj-$(CONFIG_DRM_VGEM) += vgem/
obj-$(CONFIG_DRM_NOUVEAU) +=nouveau/
obj-$(CONFIG_DRM_EXYNOS) +=exynos/
obj-y += i2c/
diff --git a/drivers/gpu/drm/vgem/Makefile b/drivers/gpu/drm/vgem/Makefile
new file mode 100644
index 0000000..3f4c7b8
--- /dev/null
+++ b/drivers/gpu/drm/vgem/Makefile
@@ -0,0 +1,4 @@
+ccflags-y := -Iinclude/drm
+vgem-y := vgem_drv.o
+
+obj-$(CONFIG_DRM_VGEM) += vgem.o
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
new file mode 100644
index 0000000..82c6787
--- /dev/null
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -0,0 +1,262 @@
+/*
+ * Copyright 2011 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software")
+ * to deal in the software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * them Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ * Adam Jackson <ajax at redhat.com>
+ */
+
+/**
+ * This is vgem, a (non-hardware-backed) GEM service. This is used by Mesa's
+ * software renderer and the X server for efficient buffer sharing.
+ */
+
+#include "drmP.h"
+#include "drm.h"
+#include "vgem_drm.h"
+#include <linux/module.h>
+#include <linux/ramfs.h>
+
+#define DRIVER_NAME "vgem"
+#define DRIVER_DESC "Virtual GEM provider"
+#define DRIVER_DATE "20120112"
+#define DRIVER_MAJOR 1
+#define DRIVER_MINOR 0
+
+static int vgem_load(struct drm_device *dev, unsigned long flags)
+{
+ return 0;
+}
+
+static int vgem_unload(struct drm_device *dev)
+{
+ return 0;
+}
+
+static void vgem_preclose(struct drm_device *dev, struct drm_file *file)
+{
+}
+
+static void vgem_lastclose(struct drm_device *dev)
+{
+}
+
+static int vgem_gem_init_object(struct drm_gem_object *obj)
+{
+ return 0;
+}
+
+static void vgem_gem_free_object(struct drm_gem_object *obj)
+{
+ if (obj->map_list.map)
+ drm_gem_free_mmap_offset(obj);
+
+ drm_gem_object_release(obj);
+}
+
+/* XXX I don't think this is ever hit */
+static int vgem_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ BUG();
+}
+
+static struct vm_operations_struct vgem_gem_vm_ops = {
+ .fault = vgem_gem_fault,
+ .open = drm_gem_vm_open,
+ .close = drm_gem_vm_close,
+};
+
+/* ioctls */
+
+static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,
+ struct drm_file *file,
+ unsigned int *handle,
+ unsigned long size)
+{
+ int err;
+ struct drm_gem_object *gem_object;
+
+ size = roundup(size, PAGE_SIZE);
+
+ gem_object = kzalloc(sizeof(*gem_object), GFP_KERNEL);
+ if (!gem_object)
+ return ERR_PTR(-ENOMEM);
+
+ if ((err = drm_gem_object_init(dev, gem_object, size)))
+ goto out;
+
+ if ((err = drm_gem_create_mmap_offset(gem_object)))
+ goto mmap_out;
+
+ if ((err = drm_gem_handle_create(file, gem_object, handle)))
+ goto handle_out;
+
+ drm_gem_object_unreference_unlocked(gem_object);
+
+ return gem_object;
+
+handle_out:
+ drm_gem_free_mmap_offset(gem_object);
+
+mmap_out:
+ drm_gem_object_release(gem_object);
+
+out:
+ kfree(gem_object);
+
+ return ERR_PTR(err);
+}
+
+static int vgem_gem_create_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file)
+{
+ struct vgem_gem_create *args = data;
+ struct drm_gem_object *gem_object;
+
+ gem_object = vgem_gem_create(dev, file, &args->handle, args->size);
+
+ if (IS_ERR(gem_object))
+ return PTR_ERR(gem_object);
+
+ return 0;
+}
+
+static int vgem_gem_mmap_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file)
+{
+ struct vgem_gem_mmap *args = data;
+ struct drm_gem_object *obj;
+ uintptr_t addr;
+
+ obj = drm_gem_object_lookup(dev, file, args->handle);
+ if (!obj)
+ return -ENOENT;
+
+ obj->filp->private_data = obj;
+
+ down_write(¤t->mm->mmap_sem);
+ addr = do_mmap(obj->filp, 0, args->size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, 0);
+ up_write(¤t->mm->mmap_sem);
+
+ drm_gem_object_unreference_unlocked(obj);
+
+ if (IS_ERR((void *)addr))
+ return PTR_ERR((void *)addr);
+
+ args->mapped = addr;
+
+ return 0;
+}
+
+static struct drm_ioctl_desc vgem_ioctls[] = {
+ DRM_IOCTL_DEF_DRV(VGEM_GEM_CREATE, vgem_gem_create_ioctl,
+ DRM_UNLOCKED | DRM_AUTH),
+ DRM_IOCTL_DEF_DRV(VGEM_GEM_MMAP, vgem_gem_mmap_ioctl,
+ DRM_UNLOCKED | DRM_AUTH),
+};
+
+static struct drm_driver vgem_driver = {
+ .driver_features = DRIVER_BUS_PLATFORM | DRIVER_GEM,
+ .load = vgem_load,
+ .unload = vgem_unload,
+ .preclose = vgem_preclose,
+ .lastclose = vgem_lastclose,
+ .gem_init_object = vgem_gem_init_object,
+ .gem_free_object = vgem_gem_free_object,
+ .gem_vm_ops = &vgem_gem_vm_ops,
+ .ioctls = vgem_ioctls,
+ .fops = {
+ .owner = THIS_MODULE,
+ .open = drm_open,
+ .mmap = drm_gem_mmap,
+ .poll = drm_poll,
+ .read = drm_read,
+ .unlocked_ioctl = drm_ioctl,
+ .release = drm_release,
+ },
+ .name = DRIVER_NAME,
+ .desc = DRIVER_DESC,
+ .date = DRIVER_DATE,
+ .major = DRIVER_MAJOR,
+ .minor = DRIVER_MINOR,
+};
+
+static int vgem_platform_probe(struct platform_device *pdev)
+{
+ vgem_driver.num_ioctls = DRM_ARRAY_SIZE(vgem_ioctls);
+
+ return drm_platform_init(&vgem_driver, pdev);
+}
+
+static int vgem_platform_remove(struct platform_device *pdev)
+{
+ drm_platform_exit(&vgem_driver, pdev);
+
+ return 0;
+}
+
+static struct platform_driver vgem_platform_driver = {
+ .probe = vgem_platform_probe,
+ .remove = __devexit_p(vgem_platform_remove),
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = DRIVER_NAME,
+ },
+};
+
+static struct platform_device *vgem_device;
+
+static int __init vgem_init(void)
+{
+ int ret;
+
+ if ((ret = platform_driver_register(&vgem_platform_driver)))
+ return ret;
+
+ vgem_device = platform_device_alloc("vgem", -1);
+ if (!vgem_device) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = platform_device_add(vgem_device);
+ if (!ret)
+ return 0;
+
+out:
+ platform_device_put(vgem_device);
+ platform_driver_unregister(&vgem_platform_driver);
+
+ return ret;
+}
+
+static void __exit vgem_exit(void)
+{
+ platform_device_unregister(vgem_device);
+ platform_driver_unregister(&vgem_platform_driver);
+}
+
+module_init(vgem_init);
+module_exit(vgem_exit);
+
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL and additional rights");
diff --git a/include/drm/vgem_drm.h b/include/drm/vgem_drm.h
new file mode 100644
index 0000000..d73b537
--- /dev/null
+++ b/include/drm/vgem_drm.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2011 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software")
+ * to deal in the software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * them Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef VGEM_DRM_H
+#define VGEM_DRM_H
+
+/* Bare API largely ripped off from exynos driver */
+
+struct vgem_gem_create {
+ unsigned int size;
+ unsigned int flags;
+ unsigned int handle;
+};
+
+struct vgem_gem_mmap {
+ unsigned int handle;
+ unsigned int size;
+ uint64_t mapped;
+};
+
+#define DRM_VGEM_GEM_CREATE 0x00
+#define DRM_VGEM_GEM_MMAP 0x01
+
+#define DRM_IOCTL_VGEM_GEM_CREATE \
+ DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_CREATE, \
+ struct vgem_gem_create)
+
+#define DRM_IOCTL_VGEM_GEM_MMAP \
+ DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_MMAP, \
+ struct vgem_gem_mmap)
+
+#endif
--
1.7.7.5
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