From: Tomasz Stanislawski t.stanislaws@samsung.com

This patch adds the framework for buffer sharing via a file descriptor. A driver that use shared buffer (shrbuf) can export a memory description by transforming it into a file descriptor. The reverse operation (import) is done by obtaining a memory description from a file descriptor. The driver is responsible to get and put callbacks to avoid resource leakage. Current implementation is dedicated for dma-contiguous buffers but scatter-gather lists will be use in the future.

The framework depends on anonfd framework which is used to create files that are not associated with any inode.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- drivers/base/Kconfig | 11 +++++ drivers/base/Makefile | 1 + drivers/base/shared-buffer.c | 96 +++++++++++++++++++++++++++++++++++++++++ include/linux/shared-buffer.h | 55 +++++++++++++++++++++++ 4 files changed, 163 insertions(+), 0 deletions(-) create mode 100644 drivers/base/shared-buffer.c create mode 100644 include/linux/shared-buffer.h

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index d57e8d0..d75a038 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -168,4 +168,15 @@ config SYS_HYPERVISOR bool default n

+config SHARED_BUFFER + bool "Framework for buffer sharing between drivers" + depends on ANON_INODES + help + This option enables the framework for buffer sharing between + multiple drivers. A buffer is associated with a file descriptor + using driver API's extensions. The descriptor is passed to other + driver. + + If you are unsure about this, Say N here. + endmenu diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 4c5701c..eeeb813 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -8,6 +8,7 @@ obj-$(CONFIG_DEVTMPFS) += devtmpfs.o obj-y += power/ obj-$(CONFIG_HAS_DMA) += dma-mapping.o obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o +obj-$(CONFIG_SHARED_BUFFER) += shared-buffer.o obj-$(CONFIG_ISA) += isa.o obj-$(CONFIG_FW_LOADER) += firmware_class.o obj-$(CONFIG_NUMA) += node.o diff --git a/drivers/base/shared-buffer.c b/drivers/base/shared-buffer.c new file mode 100644 index 0000000..105b696 --- /dev/null +++ b/drivers/base/shared-buffer.c @@ -0,0 +1,96 @@ +/* + * Framework for shared buffer + * + * Copyright (C) 2011 Samsung Electronics Co., Ltd. + * Author: Tomasz Stanislawski, t.stanislaws@samsung.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/anon_inodes.h> +#include <linux/dma-mapping.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/shared-buffer.h> + +/** + * shrbuf_release() - release resources of shrbuf file + * @inode: a file's inode, not used + * @file: file pointer + * + * The function unbinds shrbuf structure from a file + */ +static int shrbuf_release(struct inode *inode, struct file *file) +{ + struct shrbuf *sb = file->private_data; + + /* decrease reference counter increased in shrbuf_export */ + sb->put(sb); + return 0; +} + +static const struct file_operations shrbuf_fops = { + .release = shrbuf_release, +}; + +/** + * shrbuf_export() - transforms shrbuf into a file descriptor + * @sb: shared buffer instance to be exported + * + * The function creates a file descriptor associated with a shared buffer + * + * Returns file descriptor or appropriate error on failure + */ +int shrbuf_export(struct shrbuf *sb) +{ + int fd; + + BUG_ON(!sb || !sb->get || !sb->put); + /* binding shrbuf to a file so reference count in increased */ + sb->get(sb); + /* obtaing file descriptor without inode */ + fd = anon_inode_getfd("shrbuf", &shrbuf_fops, sb, 0); + /* releasing shrbuf on failure */ + if (fd < 0) + sb->put(sb); + return fd; +} + +EXPORT_SYMBOL(shrbuf_export); + +/** + * shrbuf_import() - obtain shrbuf structure from a file descriptor + * @fd: file descriptor + * + * The function obtains an instance of a shared buffer from a file descriptor + * Call sb->put when imported buffer is not longer needed + * + * Returns pointer to a shared buffer or error pointer on failure + */ +struct shrbuf *shrbuf_import(int fd) +{ + struct file *file; + struct shrbuf *sb; + + /* obtain a file, assure that it will not be released */ + file = fget(fd); + /* check if descriptor is incorrect */ + if (!file) + return ERR_PTR(-EBADF); + /* check if dealing with shrbuf-file */ + if (file->f_op != &shrbuf_fops) { + fput(file); + return ERR_PTR(-EINVAL); + } + /* add user of shared buffer */ + sb = file->private_data; + sb->get(sb); + /* release the file */ + fput(file); + + return sb; +} + +EXPORT_SYMBOL(shrbuf_import); + diff --git a/include/linux/shared-buffer.h b/include/linux/shared-buffer.h new file mode 100644 index 0000000..ac0822f --- /dev/null +++ b/include/linux/shared-buffer.h @@ -0,0 +1,55 @@ +/* + * Framework for shared buffer + * + * Copyright (C) 2011 Samsung Electronics Co., Ltd. + * Author: Tomasz Stanislawski, t.stanislaws@samsung.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _LINUX_SHARED_BUFFER_H +#define _LINUX_SHARED_BUFFER_H + +#include <linux/err.h> + +/** + * struct shrbuf - shared buffer instance + * @get: increase number of a buffer's users + * @put: decrease number of a buffer's user, release resources if needed + * @dma_addr: start address of a contiguous buffer + * @size: size of a contiguous buffer + * + * Both get/put methods are required. The structure is dedicated for + * embedding. The fields dma_addr and size are used for proof-of-concept + * purpose. They will be substituted by scatter-gatter lists. + */ +struct shrbuf { + void (*get)(struct shrbuf *); + void (*put)(struct shrbuf *); + unsigned long dma_addr; + unsigned long size; +}; + +#ifdef CONFIG_SHARED_BUFFER + +int shrbuf_export(struct shrbuf *sb); + +struct shrbuf *shrbuf_import(int fd); + +#else + +static inline int shrbuf_export(struct shrbuf *sb) +{ + return -ENODEV; +} + +static inline struct shrbuf *shrbuf_import(int fd) +{ + return ERR_PTR(-ENODEV); +} + +#endif /* CONFIG_SHARED_BUFFER */ + +#endif /* _LINUX_SHARED_BUFFER_H */

From: Tomasz Stanislawski t.stanislaws@samsung.com

This patch adds extension to V4L2 api. It allow to export a mmap buffer as file descriptor. New ioctl VIDIOC_EXPBUF is added. It takes a buffer offset used by mmap and return a file descriptor on success.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- drivers/media/video/v4l2-ioctl.c | 10 ++++++++++ include/linux/videodev2.h | 8 ++++++++ include/media/v4l2-ioctl.h | 1 + 3 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c index 660b486..0a19fd4 100644 --- a/drivers/media/video/v4l2-ioctl.c +++ b/drivers/media/video/v4l2-ioctl.c @@ -1145,6 +1145,16 @@ static long __video_do_ioctl(struct file *file, dbgbuf(cmd, vfd, p); break; } + case VIDIOC_EXPBUF: + { + unsigned int *p = arg; + + if (!ops->vidioc_expbuf) + break; + + ret = ops->vidioc_expbuf(file, fh, *p); + break; + } case VIDIOC_DQBUF: { struct v4l2_buffer *p = arg; diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index 7c77c4e..cae7908 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h @@ -185,6 +185,7 @@ enum v4l2_memory { V4L2_MEMORY_MMAP = 1, V4L2_MEMORY_USERPTR = 2, V4L2_MEMORY_OVERLAY = 3, + V4L2_MEMORY_SHRBUF = 4, };

/* see also http://vektor.theorem.ca/graphics/ycbcr/ */ @@ -564,6 +565,8 @@ struct v4l2_requestbuffers { * should be passed to mmap() called on the video node) * @userptr: when memory is V4L2_MEMORY_USERPTR, a userspace pointer * pointing to this plane + * @fd: when memory is V4L2_MEMORY_SHRBUF, a userspace file + * descriptor associated with this plane * @data_offset: offset in the plane to the start of data; usually 0, * unless there is a header in front of the data * @@ -578,6 +581,7 @@ struct v4l2_plane { union { __u32 mem_offset; unsigned long userptr; + int fd; } m; __u32 data_offset; __u32 reserved[11]; @@ -600,6 +604,8 @@ struct v4l2_plane { * (or a "cookie" that should be passed to mmap() as offset) * @userptr: for non-multiplanar buffers with memory == V4L2_MEMORY_USERPTR; * a userspace pointer pointing to this buffer + * @fd: for non-multiplanar buffers with memory == V4L2_MEMORY_SHRBUF; + * a userspace file descriptor associated with this buffer * @planes: for multiplanar buffers; userspace pointer to the array of plane * info structs for this buffer * @length: size in bytes of the buffer (NOT its payload) for single-plane @@ -626,6 +632,7 @@ struct v4l2_buffer { __u32 offset; unsigned long userptr; struct v4l2_plane *planes; + int fd; } m; __u32 length; __u32 input; @@ -1868,6 +1875,7 @@ struct v4l2_dbg_chip_ident { #define VIDIOC_S_FBUF _IOW('V', 11, struct v4l2_framebuffer) #define VIDIOC_OVERLAY _IOW('V', 14, int) #define VIDIOC_QBUF _IOWR('V', 15, struct v4l2_buffer) +#define VIDIOC_EXPBUF _IOWR('V', 16, unsigned int) #define VIDIOC_DQBUF _IOWR('V', 17, struct v4l2_buffer) #define VIDIOC_STREAMON _IOW('V', 18, int) #define VIDIOC_STREAMOFF _IOW('V', 19, int) diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h index dd9f1e7..20932e3 100644 --- a/include/media/v4l2-ioctl.h +++ b/include/media/v4l2-ioctl.h @@ -121,6 +121,7 @@ struct v4l2_ioctl_ops { int (*vidioc_querybuf)(struct file *file, void *fh, struct v4l2_buffer *b); int (*vidioc_qbuf) (struct file *file, void *fh, struct v4l2_buffer *b); int (*vidioc_dqbuf) (struct file *file, void *fh, struct v4l2_buffer *b); + int (*vidioc_expbuf) (struct file *file, void *fh, unsigned int offset);

int (*vidioc_overlay) (struct file *file, void *fh, unsigned int i);

From: Tomasz Stanislawski t.stanislaws@samsung.com

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- drivers/media/video/videobuf2-dma-contig.c | 90 ++++++++++++++++++++++++++++ 1 files changed, 90 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index a790a5f..7baac66 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -13,6 +13,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/dma-mapping.h> +#include <linux/shared-buffer.h>

#include <media/videobuf2-core.h> #include <media/videobuf2-memops.h> @@ -27,26 +28,57 @@ struct vb2_dc_buf { dma_addr_t paddr; unsigned long size; struct vm_area_struct *vma; + struct shrbuf *sb; atomic_t refcount; struct vb2_vmarea_handler handler; };

+struct vb2_dc_shrbuf { + struct vb2_dc_buf *buf; + struct shrbuf sb; +}; + static void vb2_dma_contig_put(void *buf_priv);

+static void __dc_shrbuf_get(struct shrbuf *__sb) +{ + struct vb2_dc_shrbuf *sb = container_of(__sb, struct vb2_dc_shrbuf, sb); + struct vb2_dc_buf *buf = sb->buf; + + atomic_inc(&buf->refcount); +} + +static void __dc_shrbuf_put(struct shrbuf *__sb) +{ + struct vb2_dc_shrbuf *sb = container_of(__sb, struct vb2_dc_shrbuf, sb); + struct vb2_dc_buf *buf = sb->buf; + + vb2_dma_contig_put(buf); +} + static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size) { struct vb2_dc_conf *conf = alloc_ctx; struct vb2_dc_buf *buf; + struct vb2_dc_shrbuf *sb;

buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM);

+ sb = kzalloc(sizeof *sb, GFP_KERNEL); + if (!sb) { + kfree(buf); + return ERR_PTR(-ENOMEM); + } + buf->sb = &sb->sb; + buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->paddr, GFP_KERNEL); if (!buf->vaddr) { dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n", size); + kfree(sb); kfree(buf); return ERR_PTR(-ENOMEM); } @@ -54,6 +86,12 @@ static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size) buf->conf = conf; buf->size = size;

+ sb->buf = buf; + sb->sb.get = __dc_shrbuf_get; + sb->sb.put = __dc_shrbuf_put; + sb->sb.dma_addr = buf->paddr; + sb->sb.size = buf->size; + buf->handler.refcount = &buf->refcount; buf->handler.put = vb2_dma_contig_put; buf->handler.arg = buf; @@ -70,6 +108,7 @@ static void vb2_dma_contig_put(void *buf_priv) if (atomic_dec_and_test(&buf->refcount)) { dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr, buf->paddr); + kfree(container_of(buf->sb, struct vb2_dc_shrbuf, sb)); kfree(buf); } } @@ -148,6 +187,54 @@ static void vb2_dma_contig_put_userptr(void *mem_priv) kfree(buf); }

+static void *vb2_dma_contig_import_shrbuf(void *alloc_ctx, int fd) +{ + struct vb2_dc_buf *buf; + struct shrbuf *sb; + + buf = kzalloc(sizeof *buf, GFP_KERNEL); + if (!buf) + return ERR_PTR(-ENOMEM); + + sb = shrbuf_import(fd); + if (IS_ERR(sb)) { + printk(KERN_ERR "Failed acquiring shared buffer from fd %d\n", + fd); + kfree(buf); + return sb; + } + + buf->size = sb->size; + buf->paddr = sb->dma_addr; + buf->sb = sb; + + return buf; +} + +static void vb2_dma_contig_put_shrbuf(void *mem_priv) +{ + struct vb2_dc_buf *buf = mem_priv; + + if (!buf) + return; + + buf->sb->put(buf->sb); + kfree(buf); +} + +static int vb2_dma_contig_export_shrbuf(void *mem_priv) +{ + struct vb2_dc_buf *buf = mem_priv; + + if (!buf) + return -EINVAL; + + if (!buf->sb) + return -EINVAL; + + return shrbuf_export(buf->sb); +} + const struct vb2_mem_ops vb2_dma_contig_memops = { .alloc = vb2_dma_contig_alloc, .put = vb2_dma_contig_put, @@ -156,6 +243,9 @@ const struct vb2_mem_ops vb2_dma_contig_memops = { .mmap = vb2_dma_contig_mmap, .get_userptr = vb2_dma_contig_get_userptr, .put_userptr = vb2_dma_contig_put_userptr, + .import_shrbuf = vb2_dma_contig_import_shrbuf, + .export_shrbuf = vb2_dma_contig_export_shrbuf, + .put_shrbuf = vb2_dma_contig_put_shrbuf, .num_users = vb2_dma_contig_num_users, }; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);

From: Tomasz Stanislawski t.stanislaws@samsung.com

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- drivers/media/video/s5p-tv/mixer_video.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/drivers/media/video/s5p-tv/mixer_video.c b/drivers/media/video/s5p-tv/mixer_video.c index 43ac22f..52cb51a 100644 --- a/drivers/media/video/s5p-tv/mixer_video.c +++ b/drivers/media/video/s5p-tv/mixer_video.c @@ -591,6 +591,14 @@ static int mxr_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p) return vb2_dqbuf(&layer->vb_queue, p, file->f_flags & O_NONBLOCK); }

+static int mxr_expbuf(struct file *file, void *priv, unsigned int offset) +{ + struct mxr_layer *layer = video_drvdata(file); + + mxr_dbg(layer->mdev, "%s:%d\n", __func__, __LINE__); + return vb2_expbuf(&layer->vb_queue, offset); +} + static int mxr_streamon(struct file *file, void *priv, enum v4l2_buf_type i) { struct mxr_layer *layer = video_drvdata(file); @@ -618,6 +626,7 @@ static const struct v4l2_ioctl_ops mxr_ioctl_ops = { .vidioc_querybuf = mxr_querybuf, .vidioc_qbuf = mxr_qbuf, .vidioc_dqbuf = mxr_dqbuf, + .vidioc_expbuf = mxr_expbuf, /* Streaming control */ .vidioc_streamon = mxr_streamon, .vidioc_streamoff = mxr_streamoff, @@ -972,7 +981,7 @@ struct mxr_layer *mxr_base_layer_create(struct mxr_device *mdev,

layer->vb_queue = (struct vb2_queue) { .type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, - .io_modes = VB2_MMAP | VB2_USERPTR, + .io_modes = VB2_MMAP | VB2_USERPTR | VB2_SHRBUF, .drv_priv = layer, .buf_struct_size = sizeof(struct mxr_buffer), .ops = &mxr_video_qops,