/* * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2 * * Copyright (C) 2010 Samsung Electronics * * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation. */ #include <linux/module.h> #include <linux/mm.h> #include <linux/scatterlist.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <media/videobuf2-v4l2.h> #include <media/videobuf2-memops.h> #include <media/videobuf2-dma-sg.h> static int debug; module_param(debug, int, 0644); #define dprintk(level, fmt, arg...) \ do { \ if (debug >= level) \ printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \ } while (0) struct vb2_dma_sg_conf { struct device *dev; }; struct vb2_dma_sg_buf { struct device *dev; void *vaddr; struct page **pages; struct frame_vector *vec; int offset; enum dma_data_direction dma_dir; struct sg_table sg_table; /* * This will point to sg_table when used with the MMAP or USERPTR * memory model, and to the dma_buf sglist when used with the * DMABUF memory model. */ struct sg_table *dma_sgt; size_t size; unsigned int num_pages; atomic_t refcount; struct vb2_vmarea_handler handler; struct dma_buf_attachment *db_attach; }; static void vb2_dma_sg_put(void *buf_priv); static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf, gfp_t gfp_flags) { unsigned int last_page = 0; int size = buf->size; while (size > 0) { struct page *pages; int order; int i; order = get_order(size); /* Dont over allocate*/ if ((PAGE_SIZE << order) > size) order--; pages = NULL; while (!pages) { pages = alloc_pages(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | gfp_flags, order); if (pages) break; if (order == 0) { while (last_page--) __free_page(buf->pages[last_page]); return -ENOMEM; } order--; } split_page(pages, order); for (i = 0; i < (1 << order); i++) buf->pages[last_page++] = &pages[i]; size -= PAGE_SIZE << order; } return 0; } static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, enum dma_data_direction dma_dir, gfp_t gfp_flags) { struct vb2_dma_sg_conf *conf = alloc_ctx; struct vb2_dma_sg_buf *buf; struct sg_table *sgt; int ret; int num_pages; DEFINE_DMA_ATTRS(attrs); dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); if (WARN_ON(alloc_ctx == NULL)) return NULL; buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return NULL; buf->vaddr = NULL; buf->dma_dir = dma_dir; buf->offset = 0; buf->size = size; /* size is already page aligned */ buf->num_pages = size >> PAGE_SHIFT; buf->dma_sgt = &buf->sg_table; buf->pages = kzalloc(buf->num_pages * sizeof(struct page *), GFP_KERNEL); if (!buf->pages) goto fail_pages_array_alloc; ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags); if (ret) goto fail_pages_alloc; ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, buf->num_pages, 0, size, GFP_KERNEL); if (ret) goto fail_table_alloc; /* Prevent the device from being released while the buffer is used */ buf->dev = get_device(conf->dev); sgt = &buf->sg_table; /* * No need to sync to the device, this will happen later when the * prepare() memop is called. */ sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, &attrs); if (!sgt->nents) goto fail_map; buf->handler.refcount = &buf->refcount; buf->handler.put = vb2_dma_sg_put; buf->handler.arg = buf; atomic_inc(&buf->refcount); dprintk(1, "%s: Allocated buffer of %d pages\n", __func__, buf->num_pages); return buf; fail_map: put_device(buf->dev); sg_free_table(buf->dma_sgt); fail_table_alloc: num_pages = buf->num_pages; while (num_pages--) __free_page(buf->pages[num_pages]); fail_pages_alloc: kfree(buf->pages); fail_pages_array_alloc: kfree(buf); return NULL; } static void vb2_dma_sg_put(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; struct sg_table *sgt = &buf->sg_table; int i = buf->num_pages; if (atomic_dec_and_test(&buf->refcount)) { DEFINE_DMA_ATTRS(attrs); dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, buf->num_pages); dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, &attrs); if (buf->vaddr) vm_unmap_ram(buf->vaddr, buf->num_pages); sg_free_table(buf->dma_sgt); while (--i >= 0) __free_page(buf->pages[i]); kfree(buf->pages); put_device(buf->dev); kfree(buf); } } static void vb2_dma_sg_prepare(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt; /* DMABUF exporter will flush the cache for us */ if (buf->db_attach) return; dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); } static void vb2_dma_sg_finish(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt; /* DMABUF exporter will flush the cache for us */ if (buf->db_attach) return; dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); } static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, unsigned long size, enum dma_data_direction dma_dir) { struct vb2_dma_sg_conf *conf = alloc_ctx; struct vb2_dma_sg_buf *buf; struct sg_table *sgt; DEFINE_DMA_ATTRS(attrs); struct frame_vector *vec; dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return NULL; buf->vaddr = NULL; buf->dev = conf->dev; buf->dma_dir = dma_dir; buf->offset = vaddr & ~PAGE_MASK; buf->size = size; buf->dma_sgt = &buf->sg_table; vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE); if (IS_ERR(vec)) goto userptr_fail_pfnvec; buf->vec = vec; buf->pages = frame_vector_pages(vec); if (IS_ERR(buf->pages)) goto userptr_fail_sgtable; buf->num_pages = frame_vector_count(vec); if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages, buf->num_pages, buf->offset, size, 0)) goto userptr_fail_sgtable; sgt = &buf->sg_table; /* * No need to sync to the device, this will happen later when the * prepare() memop is called. */ sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, &attrs); if (!sgt->nents) goto userptr_fail_map; return buf; userptr_fail_map: sg_free_table(&buf->sg_table); userptr_fail_sgtable: vb2_destroy_framevec(vec); userptr_fail_pfnvec: kfree(buf); return NULL; } /* * @put_userptr: inform the allocator that a USERPTR buffer will no longer * be used */ static void vb2_dma_sg_put_userptr(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; struct sg_table *sgt = &buf->sg_table; int i = buf->num_pages; DEFINE_DMA_ATTRS(attrs); dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); dprintk(1, "%s: Releasing userspace buffer of %d pages\n", __func__, buf->num_pages); dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir, &attrs); if (buf->vaddr) vm_unmap_ram(buf->vaddr, buf->num_pages); sg_free_table(buf->dma_sgt); while (--i >= 0) { if (buf->dma_dir == DMA_FROM_DEVICE) set_page_dirty_lock(buf->pages[i]); } vb2_destroy_framevec(buf->vec); kfree(buf); } static void *vb2_dma_sg_vaddr(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; BUG_ON(!buf); if (!buf->vaddr) { if (buf->db_attach) buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf); else buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1, PAGE_KERNEL); } /* add offset in case userptr is not page-aligned */ return buf->vaddr ? buf->vaddr + buf->offset : NULL; } static unsigned int vb2_dma_sg_num_users(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; return atomic_read(&buf->refcount); } static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) { struct vb2_dma_sg_buf *buf = buf_priv; unsigned long uaddr = vma->vm_start; unsigned long usize = vma->vm_end - vma->vm_start; int i = 0; if (!buf) { printk(KERN_ERR "No memory to map\n"); return -EINVAL; } do { int ret; ret = vm_insert_page(vma, uaddr, buf->pages[i++]); if (ret) { printk(KERN_ERR "Remapping memory, error: %d\n", ret); return ret; } uaddr += PAGE_SIZE; usize -= PAGE_SIZE; } while (usize > 0); /* * Use common vm_area operations to track buffer refcount. */ vma->vm_private_data = &buf->handler; vma->vm_ops = &vb2_common_vm_ops; vma->vm_ops->open(vma); return 0; } /*********************************************/ /* DMABUF ops for exporters */ /*********************************************/ struct vb2_dma_sg_attachment { struct sg_table sgt; enum dma_data_direction dma_dir; }; static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev, struct dma_buf_attachment *dbuf_attach) { struct vb2_dma_sg_attachment *attach; unsigned int i; struct scatterlist *rd, *wr; struct sg_table *sgt; struct vb2_dma_sg_buf *buf = dbuf->priv; int ret; attach = kzalloc(sizeof(*attach), GFP_KERNEL); if (!attach) return -ENOMEM; sgt = &attach->sgt; /* Copy the buf->base_sgt scatter list to the attachment, as we can't * map the same scatter list to multiple attachments at the same time. */ ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); if (ret) { kfree(attach); return -ENOMEM; } rd = buf->dma_sgt->sgl; wr = sgt->sgl; for (i = 0; i < sgt->orig_nents; ++i) { sg_set_page(wr, sg_page(rd), rd->length, rd->offset); rd = sg_next(rd); wr = sg_next(wr); } attach->dma_dir = DMA_NONE; dbuf_attach->priv = attach; return 0; } static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, struct dma_buf_attachment *db_attach) { struct vb2_dma_sg_attachment *attach = db_attach->priv; struct sg_table *sgt; if (!attach) return; sgt = &attach->sgt; /* release the scatterlist cache */ if (attach->dma_dir != DMA_NONE) dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, attach->dma_dir); sg_free_table(sgt); kfree(attach); db_attach->priv = NULL; } static struct sg_table *vb2_dma_sg_dmabuf_ops_map( struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) { struct vb2_dma_sg_attachment *attach = db_attach->priv; /* stealing dmabuf mutex to serialize map/unmap operations */ struct mutex *lock = &db_attach->dmabuf->lock; struct sg_table *sgt; mutex_lock(lock); sgt = &attach->sgt; /* return previously mapped sg table */ if (attach->dma_dir == dma_dir) { mutex_unlock(lock); return sgt; } /* release any previous cache */ if (attach->dma_dir != DMA_NONE) { dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, attach->dma_dir); attach->dma_dir = DMA_NONE; } /* mapping to the client with new direction */ sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir); if (!sgt->nents) { pr_err("failed to map scatterlist\n"); mutex_unlock(lock); return ERR_PTR(-EIO); } attach->dma_dir = dma_dir; mutex_unlock(lock); return sgt; } static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, struct sg_table *sgt, enum dma_data_direction dma_dir) { /* nothing to be done here */ } static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) { /* drop reference obtained in vb2_dma_sg_get_dmabuf */ vb2_dma_sg_put(dbuf->priv); } static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum) { struct vb2_dma_sg_buf *buf = dbuf->priv; return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL; } static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) { struct vb2_dma_sg_buf *buf = dbuf->priv; return vb2_dma_sg_vaddr(buf); } static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, struct vm_area_struct *vma) { return vb2_dma_sg_mmap(dbuf->priv, vma); } static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { .attach = vb2_dma_sg_dmabuf_ops_attach, .detach = vb2_dma_sg_dmabuf_ops_detach, .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, .kmap = vb2_dma_sg_dmabuf_ops_kmap, .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap, .vmap = vb2_dma_sg_dmabuf_ops_vmap, .mmap = vb2_dma_sg_dmabuf_ops_mmap, .release = vb2_dma_sg_dmabuf_ops_release, }; static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) { struct vb2_dma_sg_buf *buf = buf_priv; struct dma_buf *dbuf; DEFINE_DMA_BUF_EXPORT_INFO(exp_info); exp_info.ops = &vb2_dma_sg_dmabuf_ops; exp_info.size = buf->size; exp_info.flags = flags; exp_info.priv = buf; if (WARN_ON(!buf->dma_sgt)) return NULL; dbuf = dma_buf_export(&exp_info); if (IS_ERR(dbuf)) return NULL; /* dmabuf keeps reference to vb2 buffer */ atomic_inc(&buf->refcount); return dbuf; } /*********************************************/ /* callbacks for DMABUF buffers */ /*********************************************/ static int vb2_dma_sg_map_dmabuf(void *mem_priv) { struct vb2_dma_sg_buf *buf = mem_priv; struct sg_table *sgt; if (WARN_ON(!buf->db_attach)) { pr_err("trying to pin a non attached buffer\n"); return -EINVAL; } if (WARN_ON(buf->dma_sgt)) { pr_err("dmabuf buffer is already pinned\n"); return 0; } /* get the associated scatterlist for this buffer */ sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); if (IS_ERR(sgt)) { pr_err("Error getting dmabuf scatterlist\n"); return -EINVAL; } buf->dma_sgt = sgt; buf->vaddr = NULL; return 0; } static void vb2_dma_sg_unmap_dmabuf(void *mem_priv) { struct vb2_dma_sg_buf *buf = mem_priv; struct sg_table *sgt = buf->dma_sgt; if (WARN_ON(!buf->db_attach)) { pr_err("trying to unpin a not attached buffer\n"); return; } if (WARN_ON(!sgt)) { pr_err("dmabuf buffer is already unpinned\n"); return; } if (buf->vaddr) { dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr); buf->vaddr = NULL; } dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); buf->dma_sgt = NULL; } static void vb2_dma_sg_detach_dmabuf(void *mem_priv) { struct vb2_dma_sg_buf *buf = mem_priv; /* if vb2 works correctly you should never detach mapped buffer */ if (WARN_ON(buf->dma_sgt)) vb2_dma_sg_unmap_dmabuf(buf); /* detach this attachment */ dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); kfree(buf); } static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf, unsigned long size, enum dma_data_direction dma_dir) { struct vb2_dma_sg_conf *conf = alloc_ctx; struct vb2_dma_sg_buf *buf; struct dma_buf_attachment *dba; if (dbuf->size < size) return ERR_PTR(-EFAULT); buf = kzalloc(sizeof(*buf), GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); buf->dev = conf->dev; /* create attachment for the dmabuf with the user device */ dba = dma_buf_attach(dbuf, buf->dev); if (IS_ERR(dba)) { pr_err("failed to attach dmabuf\n"); kfree(buf); return dba; } buf->dma_dir = dma_dir; buf->size = size; buf->db_attach = dba; return buf; } static void *vb2_dma_sg_cookie(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; return buf->dma_sgt; } const struct vb2_mem_ops vb2_dma_sg_memops = { .alloc = vb2_dma_sg_alloc, .put = vb2_dma_sg_put, .get_userptr = vb2_dma_sg_get_userptr, .put_userptr = vb2_dma_sg_put_userptr, .prepare = vb2_dma_sg_prepare, .finish = vb2_dma_sg_finish, .vaddr = vb2_dma_sg_vaddr, .mmap = vb2_dma_sg_mmap, .num_users = vb2_dma_sg_num_users, .get_dmabuf = vb2_dma_sg_get_dmabuf, .map_dmabuf = vb2_dma_sg_map_dmabuf, .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, .attach_dmabuf = vb2_dma_sg_attach_dmabuf, .detach_dmabuf = vb2_dma_sg_detach_dmabuf, .cookie = vb2_dma_sg_cookie, }; EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); void *vb2_dma_sg_init_ctx(struct device *dev) { struct vb2_dma_sg_conf *conf; conf = kzalloc(sizeof(*conf), GFP_KERNEL); if (!conf) return ERR_PTR(-ENOMEM); conf->dev = dev; return conf; } EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx); void vb2_dma_sg_cleanup_ctx(void *alloc_ctx) { if (!IS_ERR_OR_NULL(alloc_ctx)) kfree(alloc_ctx); } EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx); MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); MODULE_AUTHOR("Andrzej Pietrasiewicz"); MODULE_LICENSE("GPL");