* the Free Software Foundation.
*/
+#include <linux/dma-buf.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
/* MMAP related */
struct vb2_vmarea_handler handler;
atomic_t refcount;
+ struct sg_table *sgt_base;
/* USERPTR related */
struct vm_area_struct *vma;
+
+ /* DMABUF related */
+ struct dma_buf_attachment *db_attach;
};
/*********************************************/
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
- if (!sgt)
+ /* DMABUF exporter will flush the cache for us */
+ if (!sgt || buf->db_attach)
return;
dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
- if (!sgt)
+ /* DMABUF exporter will flush the cache for us */
+ if (!sgt || buf->db_attach)
return;
dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
if (!atomic_dec_and_test(&buf->refcount))
return;
+ if (buf->sgt_base) {
+ sg_free_table(buf->sgt_base);
+ kfree(buf->sgt_base);
+ }
dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
+ put_device(buf->dev);
kfree(buf);
}
if (!buf)
return ERR_PTR(-ENOMEM);
+ /* align image size to PAGE_SIZE */
+ size = PAGE_ALIGN(size);
+
buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
if (!buf->vaddr) {
dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
return ERR_PTR(-ENOMEM);
}
- buf->dev = dev;
+ /* Prevent the device from being released while the buffer is used */
+ buf->dev = get_device(dev);
buf->size = size;
buf->handler.refcount = &buf->refcount;
static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
{
struct vb2_dc_buf *buf = buf_priv;
+ int ret;
if (!buf) {
printk(KERN_ERR "No buffer to map\n");
return -EINVAL;
}
- return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
- &vb2_common_vm_ops, &buf->handler);
+ /*
+ * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
+ * map whole buffer
+ */
+ vma->vm_pgoff = 0;
+
+ ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
+ buf->dma_addr, buf->size);
+
+ if (ret) {
+ pr_err("Remapping memory failed, error: %d\n", ret);
+ return ret;
+ }
+
+ vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_private_data = &buf->handler;
+ vma->vm_ops = &vb2_common_vm_ops;
+
+ vma->vm_ops->open(vma);
+
+ pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
+ __func__, (unsigned long)buf->dma_addr, vma->vm_start,
+ buf->size);
+
+ return 0;
+}
+
+/*********************************************/
+/* DMABUF ops for exporters */
+/*********************************************/
+
+struct vb2_dc_attachment {
+ struct sg_table sgt;
+ enum dma_data_direction dir;
+};
+
+static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
+ struct dma_buf_attachment *dbuf_attach)
+{
+ struct vb2_dc_attachment *attach;
+ unsigned int i;
+ struct scatterlist *rd, *wr;
+ struct sg_table *sgt;
+ struct vb2_dc_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->sgt_base->orig_nents, GFP_KERNEL);
+ if (ret) {
+ kfree(attach);
+ return -ENOMEM;
+ }
+
+ rd = buf->sgt_base->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->dir = DMA_NONE;
+ dbuf_attach->priv = attach;
+
+ return 0;
+}
+
+static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
+ struct dma_buf_attachment *db_attach)
+{
+ struct vb2_dc_attachment *attach = db_attach->priv;
+ struct sg_table *sgt;
+
+ if (!attach)
+ return;
+
+ sgt = &attach->sgt;
+
+ /* release the scatterlist cache */
+ if (attach->dir != DMA_NONE)
+ dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dir);
+ sg_free_table(sgt);
+ kfree(attach);
+ db_attach->priv = NULL;
+}
+
+static struct sg_table *vb2_dc_dmabuf_ops_map(
+ struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
+{
+ struct vb2_dc_attachment *attach = db_attach->priv;
+ /* stealing dmabuf mutex to serialize map/unmap operations */
+ struct mutex *lock = &db_attach->dmabuf->lock;
+ struct sg_table *sgt;
+ int ret;
+
+ mutex_lock(lock);
+
+ sgt = &attach->sgt;
+ /* return previously mapped sg table */
+ if (attach->dir == dir) {
+ mutex_unlock(lock);
+ return sgt;
+ }
+
+ /* release any previous cache */
+ if (attach->dir != DMA_NONE) {
+ dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dir);
+ attach->dir = DMA_NONE;
+ }
+
+ /* mapping to the client with new direction */
+ ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
+ if (ret <= 0) {
+ pr_err("failed to map scatterlist\n");
+ mutex_unlock(lock);
+ return ERR_PTR(-EIO);
+ }
+
+ attach->dir = dir;
+
+ mutex_unlock(lock);
+
+ return sgt;
+}
+
+static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
+ struct sg_table *sgt, enum dma_data_direction dir)
+{
+ /* nothing to be done here */
+}
+
+static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
+{
+ /* drop reference obtained in vb2_dc_get_dmabuf */
+ vb2_dc_put(dbuf->priv);
+}
+
+static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
+{
+ struct vb2_dc_buf *buf = dbuf->priv;
+
+ return buf->vaddr + pgnum * PAGE_SIZE;
+}
+
+static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
+{
+ struct vb2_dc_buf *buf = dbuf->priv;
+
+ return buf->vaddr;
+}
+
+static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
+ struct vm_area_struct *vma)
+{
+ return vb2_dc_mmap(dbuf->priv, vma);
+}
+
+static struct dma_buf_ops vb2_dc_dmabuf_ops = {
+ .attach = vb2_dc_dmabuf_ops_attach,
+ .detach = vb2_dc_dmabuf_ops_detach,
+ .map_dma_buf = vb2_dc_dmabuf_ops_map,
+ .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
+ .kmap = vb2_dc_dmabuf_ops_kmap,
+ .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
+ .vmap = vb2_dc_dmabuf_ops_vmap,
+ .mmap = vb2_dc_dmabuf_ops_mmap,
+ .release = vb2_dc_dmabuf_ops_release,
+};
+
+static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
+{
+ int ret;
+ struct sg_table *sgt;
+
+ sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
+ if (!sgt) {
+ dev_err(buf->dev, "failed to alloc sg table\n");
+ return NULL;
+ }
+
+ ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
+ buf->size);
+ if (ret < 0) {
+ dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
+ kfree(sgt);
+ return NULL;
+ }
+
+ return sgt;
+}
+
+static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
+{
+ struct vb2_dc_buf *buf = buf_priv;
+ struct dma_buf *dbuf;
+
+ if (!buf->sgt_base)
+ buf->sgt_base = vb2_dc_get_base_sgt(buf);
+
+ if (WARN_ON(!buf->sgt_base))
+ return NULL;
+
+ dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
+ if (IS_ERR(dbuf))
+ return NULL;
+
+ /* dmabuf keeps reference to vb2 buffer */
+ atomic_inc(&buf->refcount);
+
+ return dbuf;
}
/*********************************************/
struct vm_area_struct *vma;
struct sg_table *sgt;
unsigned long contig_size;
+ unsigned long dma_align = dma_get_cache_alignment();
+
+ /* Only cache aligned DMA transfers are reliable */
+ if (!IS_ALIGNED(vaddr | size, dma_align)) {
+ pr_debug("user data must be aligned to %lu bytes\n", dma_align);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (!size) {
+ pr_debug("size is zero\n");
+ return ERR_PTR(-EINVAL);
+ }
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
return ERR_PTR(ret);
}
+/*********************************************/
+/* callbacks for DMABUF buffers */
+/*********************************************/
+
+static int vb2_dc_map_dmabuf(void *mem_priv)
+{
+ struct vb2_dc_buf *buf = mem_priv;
+ struct sg_table *sgt;
+ unsigned long contig_size;
+
+ 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_OR_NULL(sgt)) {
+ pr_err("Error getting dmabuf scatterlist\n");
+ return -EINVAL;
+ }
+
+ /* checking if dmabuf is big enough to store contiguous chunk */
+ contig_size = vb2_dc_get_contiguous_size(sgt);
+ if (contig_size < buf->size) {
+ pr_err("contiguous chunk is too small %lu/%lu b\n",
+ contig_size, buf->size);
+ dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+ return -EFAULT;
+ }
+
+ buf->dma_addr = sg_dma_address(sgt->sgl);
+ buf->dma_sgt = sgt;
+
+ return 0;
+}
+
+static void vb2_dc_unmap_dmabuf(void *mem_priv)
+{
+ struct vb2_dc_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;
+ }
+
+ dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+
+ buf->dma_addr = 0;
+ buf->dma_sgt = NULL;
+}
+
+static void vb2_dc_detach_dmabuf(void *mem_priv)
+{
+ struct vb2_dc_buf *buf = mem_priv;
+
+ /* if vb2 works correctly you should never detach mapped buffer */
+ if (WARN_ON(buf->dma_addr))
+ vb2_dc_unmap_dmabuf(buf);
+
+ /* detach this attachment */
+ dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
+ kfree(buf);
+}
+
+static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
+ unsigned long size, int write)
+{
+ struct vb2_dc_conf *conf = alloc_ctx;
+ struct vb2_dc_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 = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+ buf->size = size;
+ buf->db_attach = dba;
+
+ return buf;
+}
+
/*********************************************/
/* DMA CONTIG exported functions */
/*********************************************/
const struct vb2_mem_ops vb2_dma_contig_memops = {
.alloc = vb2_dc_alloc,
.put = vb2_dc_put,
+ .get_dmabuf = vb2_dc_get_dmabuf,
.cookie = vb2_dc_cookie,
.vaddr = vb2_dc_vaddr,
.mmap = vb2_dc_mmap,
.put_userptr = vb2_dc_put_userptr,
.prepare = vb2_dc_prepare,
.finish = vb2_dc_finish,
+ .map_dmabuf = vb2_dc_map_dmabuf,
+ .unmap_dmabuf = vb2_dc_unmap_dmabuf,
+ .attach_dmabuf = vb2_dc_attach_dmabuf,
+ .detach_dmabuf = vb2_dc_detach_dmabuf,
.num_users = vb2_dc_num_users,
};
EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
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