/* * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2 * * Copyright (C) 2010 Samsung Electronics * * Author: Pawel Osciak <pawel@osciak.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/slab.h> #include <linux/dma-mapping.h> #include <media/videobuf2-core.h> #include <media/videobuf2-memops.h> struct vb2_dc_conf { struct device *dev; }; struct vb2_dc_buf { struct vb2_dc_conf *conf; void *vaddr; dma_addr_t paddr; unsigned long size; struct vm_area_struct *vma; atomic_t refcount; struct vb2_vmarea_handler handler; }; static void vb2_dma_contig_put(void *buf_priv); static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size) { struct vb2_dc_conf *conf = alloc_ctx; struct vb2_dc_buf *buf; buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); 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", buf->size); kfree(buf); return ERR_PTR(-ENOMEM); } buf->conf = conf; buf->size = size; buf->handler.refcount = &buf->refcount; buf->handler.put = vb2_dma_contig_put; buf->handler.arg = buf; atomic_inc(&buf->refcount); return buf; } static void vb2_dma_contig_put(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; if (atomic_dec_and_test(&buf->refcount)) { dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr, buf->paddr); kfree(buf); } } static void *vb2_dma_contig_cookie(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; return &buf->paddr; } static void *vb2_dma_contig_vaddr(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; if (!buf) return 0; return buf->vaddr; } static unsigned int vb2_dma_contig_num_users(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; return atomic_read(&buf->refcount); } static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma) { struct vb2_dc_buf *buf = buf_priv; if (!buf) { printk(KERN_ERR "No buffer to map\n"); return -EINVAL; } return vb2_mmap_pfn_range(vma, buf->paddr, buf->size, &vb2_common_vm_ops, &buf->handler); } static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr, unsigned long size, int write) { struct vb2_dc_buf *buf; struct vm_area_struct *vma; dma_addr_t paddr = 0; int ret; buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); ret = vb2_get_contig_userptr(vaddr, size, &vma, &paddr); if (ret) { printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n", vaddr); kfree(buf); return ERR_PTR(ret); } buf->size = size; buf->paddr = paddr; buf->vma = vma; return buf; } static void vb2_dma_contig_put_userptr(void *mem_priv) { struct vb2_dc_buf *buf = mem_priv; if (!buf) return; vb2_put_vma(buf->vma); kfree(buf); } const struct vb2_mem_ops vb2_dma_contig_memops = { .alloc = vb2_dma_contig_alloc, .put = vb2_dma_contig_put, .cookie = vb2_dma_contig_cookie, .vaddr = vb2_dma_contig_vaddr, .mmap = vb2_dma_contig_mmap, .get_userptr = vb2_dma_contig_get_userptr, .put_userptr = vb2_dma_contig_put_userptr, .num_users = vb2_dma_contig_num_users, }; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops); void *vb2_dma_contig_init_ctx(struct device *dev) { struct vb2_dc_conf *conf; conf = kzalloc(sizeof *conf, GFP_KERNEL); if (!conf) return ERR_PTR(-ENOMEM); conf->dev = dev; return conf; } EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx); void vb2_dma_contig_cleanup_ctx(void *alloc_ctx) { kfree(alloc_ctx); } EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx); MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2"); MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>"); MODULE_LICENSE("GPL");