This patch adds support for DMABUF memory type in videobuf2. It calls relevant APIs of dma_buf for v4l reqbuf / qbuf / dqbuf operations.
For this version, the support is for videobuf2 as a user of the shared buffer; so the allocation of the buffer is done outside of V4L2. [A sample allocator of dma-buf shared buffer is given at [1]] [1]: Rob Clark's DRM: https://github.com/robclark/kernel-omap4/commits/drmplane-dmabuf Signed-off-by: Tomasz Stanislawski <t.stanisl...@samsung.com> [original work in the PoC for buffer sharing] Signed-off-by: Sumit Semwal <sumit.sem...@ti.com> Signed-off-by: Sumit Semwal <sumit.sem...@linaro.org> --- drivers/media/video/videobuf2-core.c | 186 +++++++++++++++++++++++++++++++++- include/media/videobuf2-core.h | 30 ++++++ 2 files changed, 215 insertions(+), 1 deletions(-) diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c index 95a3f5e..6cd2f97 100644 --- a/drivers/media/video/videobuf2-core.c +++ b/drivers/media/video/videobuf2-core.c @@ -107,6 +107,27 @@ static void __vb2_buf_userptr_put(struct vb2_buffer *vb) } /** + * __vb2_buf_dmabuf_put() - release memory associated with + * a DMABUF shared buffer + */ +static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb) +{ + struct vb2_queue *q = vb->vb2_queue; + unsigned int plane; + + for (plane = 0; plane < vb->num_planes; ++plane) { + void *mem_priv = vb->planes[plane].mem_priv; + + if (mem_priv) { + call_memop(q, plane, detach_dmabuf, mem_priv); + dma_buf_put(vb->planes[plane].dbuf); + vb->planes[plane].dbuf = NULL; + vb->planes[plane].mem_priv = NULL; + } + } +} + +/** * __setup_offsets() - setup unique offsets ("cookies") for every plane in * every buffer on the queue */ @@ -228,6 +249,8 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers) /* Free MMAP buffers or release USERPTR buffers */ if (q->memory == V4L2_MEMORY_MMAP) __vb2_buf_mem_free(vb); + if (q->memory == V4L2_MEMORY_DMABUF) + __vb2_buf_dmabuf_put(vb); else __vb2_buf_userptr_put(vb); } @@ -350,6 +373,13 @@ static int __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b) */ memcpy(b->m.planes, vb->v4l2_planes, b->length * sizeof(struct v4l2_plane)); + + if (q->memory == V4L2_MEMORY_DMABUF) { + unsigned int plane; + for (plane = 0; plane < vb->num_planes; ++plane) { + b->m.planes[plane].m.fd = 0; + } + } } else { /* * We use length and offset in v4l2_planes array even for @@ -361,6 +391,8 @@ static int __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b) b->m.offset = vb->v4l2_planes[0].m.mem_offset; else if (q->memory == V4L2_MEMORY_USERPTR) b->m.userptr = vb->v4l2_planes[0].m.userptr; + else if (q->memory == V4L2_MEMORY_DMABUF) + b->m.fd = 0; } /* @@ -452,6 +484,21 @@ static int __verify_mmap_ops(struct vb2_queue *q) } /** + * __verify_dmabuf_ops() - verify that all memory operations required for + * DMABUF queue type have been provided + */ +static int __verify_dmabuf_ops(struct vb2_queue *q) +{ + if (!(q->io_modes & VB2_DMABUF) || !q->mem_ops->attach_dmabuf + || !q->mem_ops->detach_dmabuf + || !q->mem_ops->map_dmabuf + || !q->mem_ops->unmap_dmabuf) + return -EINVAL; + + return 0; +} + +/** * vb2_reqbufs() - Initiate streaming * @q: videobuf2 queue * @req: struct passed from userspace to vidioc_reqbufs handler in driver @@ -485,6 +532,7 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) } if (req->memory != V4L2_MEMORY_MMAP + && req->memory != V4L2_MEMORY_DMABUF && req->memory != V4L2_MEMORY_USERPTR) { dprintk(1, "reqbufs: unsupported memory type\n"); return -EINVAL; @@ -514,6 +562,11 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) return -EINVAL; } + if (req->memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) { + dprintk(1, "reqbufs: DMABUF for current setup unsupported\n"); + return -EINVAL; + } + if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) { /* * We already have buffers allocated, so first check if they @@ -621,7 +674,8 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create) } if (create->memory != V4L2_MEMORY_MMAP - && create->memory != V4L2_MEMORY_USERPTR) { + && create->memory != V4L2_MEMORY_USERPTR + && create->memory != V4L2_MEMORY_DMABUF) { dprintk(1, "%s(): unsupported memory type\n", __func__); return -EINVAL; } @@ -645,6 +699,11 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create) return -EINVAL; } + if (create->memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) { + dprintk(1, "%s(): DMABUF for current setup unsupported\n", __func__); + return -EINVAL; + } + if (q->num_buffers == VIDEO_MAX_FRAME) { dprintk(1, "%s(): maximum number of buffers already allocated\n", __func__); @@ -840,6 +899,11 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b, b->m.planes[plane].length; } } + if (b->memory == V4L2_MEMORY_DMABUF) { + for (plane = 0; plane < vb->num_planes; ++plane) { + v4l2_planes[plane].m.fd = b->m.planes[plane].m.fd; + } + } } else { /* * Single-planar buffers do not use planes array, @@ -854,6 +918,10 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b, v4l2_planes[0].m.userptr = b->m.userptr; v4l2_planes[0].length = b->length; } + if (b->memory == V4L2_MEMORY_DMABUF) { + v4l2_planes[0].m.fd = b->m.fd; + } + } vb->v4l2_buf.field = b->field; @@ -962,6 +1030,109 @@ static int __qbuf_mmap(struct vb2_buffer *vb, const struct v4l2_buffer *b) } /** + * __qbuf_dmabuf() - handle qbuf of a DMABUF buffer + */ +static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b) +{ + struct v4l2_plane planes[VIDEO_MAX_PLANES]; + struct vb2_queue *q = vb->vb2_queue; + void *mem_priv; + unsigned int plane; + int ret; + int write = !V4L2_TYPE_IS_OUTPUT(q->type); + + /* Verify and copy relevant information provided by the userspace */ + ret = __fill_vb2_buffer(vb, b, planes); + if (ret) + return ret; + + for (plane = 0; plane < vb->num_planes; ++plane) { + struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd); + + if (IS_ERR_OR_NULL(dbuf)) { + dprintk(1, "qbuf: invalid dmabuf fd for " + "plane %d\n", plane); + ret = PTR_ERR(dbuf); + goto err; + } + + /* this doesn't get filled in until __fill_vb2_buffer(), + * since it isn't known until after dma_buf_get().. + */ + planes[plane].length = dbuf->size; + + /* Skip the plane if already verified */ + if (dbuf == vb->planes[plane].dbuf) { + dma_buf_put(dbuf); + continue; + } + + dprintk(3, "qbuf: buffer description for plane %d changed, " + "reattaching dma buf\n", plane); + + /* Release previously acquired memory if present */ + if (vb->planes[plane].mem_priv) { + call_memop(q, plane, detach_dmabuf, + vb->planes[plane].mem_priv); + dma_buf_put(vb->planes[plane].dbuf); + } + + vb->planes[plane].mem_priv = NULL; + + /* Acquire each plane's memory */ + mem_priv = q->mem_ops->attach_dmabuf( + q->alloc_ctx[plane], dbuf); + if (IS_ERR(mem_priv)) { + dprintk(1, "qbuf: failed acquiring dmabuf " + "memory for plane %d\n", plane); + ret = PTR_ERR(mem_priv); + goto err; + } + + vb->planes[plane].dbuf = dbuf; + vb->planes[plane].mem_priv = mem_priv; + } + + /* TODO: This pins the buffer(s) with dma_buf_map_attachment()).. but + * really we want to do this just before the DMA, not while queueing + * the buffer(s).. + */ + for (plane = 0; plane < vb->num_planes; ++plane) { + ret = q->mem_ops->map_dmabuf( + vb->planes[plane].mem_priv, write); + if (ret) { + dprintk(1, "qbuf: failed mapping dmabuf " + "memory for plane %d\n", plane); + goto err; + } + } + + /* + * Call driver-specific initialization on the newly acquired buffer, + * if provided. + */ + ret = call_qop(q, buf_init, vb); + if (ret) { + dprintk(1, "qbuf: buffer initialization failed\n"); + goto err; + } + + /* + * Now that everything is in order, copy relevant information + * provided by userspace. + */ + for (plane = 0; plane < vb->num_planes; ++plane) + vb->v4l2_planes[plane] = planes[plane]; + + return 0; +err: + /* In case of errors, release planes that were already acquired */ + __vb2_buf_dmabuf_put(vb); + + return ret; +} + +/** * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing */ static void __enqueue_in_driver(struct vb2_buffer *vb) @@ -985,6 +1156,9 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b) case V4L2_MEMORY_USERPTR: ret = __qbuf_userptr(vb, b); break; + case V4L2_MEMORY_DMABUF: + ret = __qbuf_dmabuf(vb, b); + break; default: WARN(1, "Invalid queue type\n"); ret = -EINVAL; @@ -1284,6 +1458,7 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) { struct vb2_buffer *vb = NULL; int ret; + unsigned int plane; if (q->fileio) { dprintk(1, "dqbuf: file io in progress\n"); @@ -1307,6 +1482,15 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) return ret; } + /* TODO: this unpins the buffer(dma_buf_unmap_attachment()).. but + * really we want tot do this just after DMA, not when the + * buffer is dequeued.. + */ + if (q->memory == V4L2_MEMORY_DMABUF) + for (plane = 0; plane < vb->num_planes; ++plane) + call_memop(q, plane, unmap_dmabuf, + vb->planes[plane].mem_priv); + switch (vb->state) { case VB2_BUF_STATE_DONE: dprintk(3, "dqbuf: Returning done buffer\n"); diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index a15d1f1..5c1836d 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -16,6 +16,7 @@ #include <linux/mutex.h> #include <linux/poll.h> #include <linux/videodev2.h> +#include <linux/dma-buf.h> struct vb2_alloc_ctx; struct vb2_fileio_data; @@ -41,6 +42,20 @@ struct vb2_fileio_data; * argument to other ops in this structure * @put_userptr: inform the allocator that a USERPTR buffer will no longer * be used + * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation; + * used for DMABUF memory types; alloc_ctx is the alloc context + * dbuf is the shared dma_buf; returns NULL on failure; + * allocator private per-buffer structure on success; + * this needs to be used for further accesses to the buffer + * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF + * buffer is no longer used; the buf_priv argument is the + * allocator private per-buffer structure previously returned + * from the attach_dmabuf callback + * @map_dmabuf: request for access to the dmabuf from allocator; the allocator + * of dmabuf is informed that this driver is going to use the + * dmabuf + * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified + * that this driver is done using the dmabuf for now * @vaddr: return a kernel virtual address to a given memory buffer * associated with the passed private structure or NULL if no * such mapping exists @@ -56,6 +71,8 @@ struct vb2_fileio_data; * Required ops for USERPTR types: get_userptr, put_userptr. * Required ops for MMAP types: alloc, put, num_users, mmap. * Required ops for read/write access types: alloc, put, num_users, vaddr + * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf, + * unmap_dmabuf. */ struct vb2_mem_ops { void *(*alloc)(void *alloc_ctx, unsigned long size); @@ -65,6 +82,16 @@ struct vb2_mem_ops { unsigned long size, int write); void (*put_userptr)(void *buf_priv); + /* Comment from Rob Clark: XXX: I think the attach / detach could be handled + * in the vb2 core, and vb2_mem_ops really just need to get/put the + * sglist (and make sure that the sglist fits it's needs..) + */ + void *(*attach_dmabuf)(void *alloc_ctx, + struct dma_buf *dbuf); + void (*detach_dmabuf)(void *buf_priv); + int (*map_dmabuf)(void *buf_priv, int write); + void (*unmap_dmabuf)(void *buf_priv); + void *(*vaddr)(void *buf_priv); void *(*cookie)(void *buf_priv); @@ -75,6 +102,7 @@ struct vb2_mem_ops { struct vb2_plane { void *mem_priv; + struct dma_buf *dbuf; }; /** @@ -83,12 +111,14 @@ struct vb2_plane { * @VB2_USERPTR: driver supports USERPTR with streaming API * @VB2_READ: driver supports read() style access * @VB2_WRITE: driver supports write() style access + * @VB2_DMABUF: driver supports DMABUF with streaming API */ enum vb2_io_modes { VB2_MMAP = (1 << 0), VB2_USERPTR = (1 << 1), VB2_READ = (1 << 2), VB2_WRITE = (1 << 3), + VB2_DMABUF = (1 << 4), }; 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