media: vb2: add support for iovmm in vb2-dma-sg

Address space management of DMA above System MMU in Exynos SoCs is not
constructed in dma-mapping but in iovmm that only provides address
space management for such DMAs. Therefore we should call iovmm_map()
and iovmm_unmap() explicitely even though videobuf2-dma-sg already
calls dma_map_sg() for mapping.
The client v4l2 drivers are intended to get DMA address from the
scatter-gather list returned by vb2_dma_sg_plane_desc() but
iovmm_map() leave it untouched because dma addresses in the scatter-
gather list is also used by cache maintenance. Therefore, DMA
addresses returned by iovmm_map() should be maintained separately.
We also provide vb2_dma_sg_plane_dma_addr() to find the DMA address
of a plane.

Change-Id: I4773d342716431d7ea889bb5e11ac3512d8193ba
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>

diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index 6808231a6bdc28f7fcf7dbd0f3fde98d5084ee26..1b1a45224b4cc0114f336719593c5f0ea02d4513 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -18,6 +18,8 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
+#include <linux/exynos_iovmm.h>
+
 #include <media/videobuf2-v4l2.h>
 #include <media/videobuf2-memops.h>
 #include <media/videobuf2-dma-sg.h>
@@ -51,6 +53,12 @@ struct vb2_dma_sg_buf {
        struct vb2_vmarea_handler       handler;
 
        struct dma_buf_attachment       *db_attach;
+       /*
+        * Our IO address space is not managed by dma-mapping. Therefore
+        * scatterlist.dma_address should not be corrupted by the IO address
+        * returned by iovmm_map() because it is used by cache maintenance.
+        */
+       dma_addr_t                      iova;
 };
 
 static void vb2_dma_sg_put(void *buf_priv);
@@ -104,6 +112,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
        struct sg_table *sgt;
        int ret;
        int num_pages;
+       int ioprot = IOMMU_READ | IOMMU_WRITE;
 
        if (WARN_ON(!dev))
                return ERR_PTR(-EINVAL);
@@ -138,13 +147,13 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
        buf->dev = get_device(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, DMA_ATTR_SKIP_CPU_SYNC);
-       if (!sgt->nents)
+
+       if (device_get_dma_attr(dev) == DEV_DMA_COHERENT)
+               ioprot |= IOMMU_CACHE;
+
+       buf->iova = iovmm_map(buf->dev, sgt->sgl, 0, size,
+                             DMA_BIDIRECTIONAL, ioprot);
+       if (IS_ERR_VALUE(buf->iova))
                goto fail_map;
 
        buf->handler.refcount = &buf->refcount;
@@ -174,14 +183,12 @@ fail_pages_array_alloc:
 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 (refcount_dec_and_test(&buf->refcount)) {
                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, DMA_ATTR_SKIP_CPU_SYNC);
+               iovmm_unmap(buf->dev, buf->iova);
                if (buf->vaddr)
                        vm_unmap_ram(buf->vaddr, buf->num_pages);
                sg_free_table(buf->dma_sgt);
@@ -225,6 +232,9 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
        struct vb2_dma_sg_buf *buf;
        struct sg_table *sgt;
        struct frame_vector *vec;
+       struct scatterlist *s;
+       int i;
+       int ioprot = IOMMU_READ | IOMMU_WRITE;
 
        if (WARN_ON(!dev))
                return ERR_PTR(-EINVAL);
@@ -255,13 +265,18 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
                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, DMA_ATTR_SKIP_CPU_SYNC);
-       if (!sgt->nents)
+
+       /* Just fixup of scatter-gather list not initialized by dma-mapping. */
+       sgt->nents = sgt->orig_nents;
+       for_each_sg(sgt->sgl, s, sgt->orig_nents, i)
+               s->dma_address = sg_phys(s);
+
+       if (device_get_dma_attr(dev) == DEV_DMA_COHERENT)
+               ioprot |= IOMMU_CACHE;
+
+       buf->iova = iovmm_map(buf->dev, sgt->sgl, 0, size,
+                             DMA_BIDIRECTIONAL, ioprot);
+       if (IS_ERR_VALUE(buf->iova))
                goto userptr_fail_map;
 
        return buf;
@@ -282,13 +297,10 @@ userptr_fail_pfnvec:
 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;
 
        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,
-                          DMA_ATTR_SKIP_CPU_SYNC);
        if (buf->vaddr)
                vm_unmap_ram(buf->vaddr, buf->num_pages);
        sg_free_table(buf->dma_sgt);
@@ -546,6 +558,7 @@ static int vb2_dma_sg_map_dmabuf(void *mem_priv)
 {
        struct vb2_dma_sg_buf *buf = mem_priv;
        struct sg_table *sgt;
+       int ioprot = IOMMU_READ | IOMMU_WRITE;
 
        if (WARN_ON(!buf->db_attach)) {
                pr_err("trying to pin a non attached buffer\n");
@@ -564,6 +577,20 @@ static int vb2_dma_sg_map_dmabuf(void *mem_priv)
                return -EINVAL;
        }
 
+       if ((buf->iova == 0) || IS_ERR_VALUE(buf->iova)) {
+               if (device_get_dma_attr(buf->dev) == DEV_DMA_COHERENT)
+                       ioprot |= IOMMU_CACHE;
+
+               buf->iova = iovmm_map(buf->dev, sgt->sgl, 0, buf->size,
+                                     DMA_BIDIRECTIONAL, ioprot);
+               if (IS_ERR_VALUE(buf->iova)) {
+                       dma_buf_unmap_attachment(buf->db_attach,
+                                                sgt, buf->dma_dir);
+                       pr_err("Error from iovmm_map()=%pad\n", &buf->iova);
+                       return (int)buf->iova;
+               }
+       }
+
        buf->dma_sgt = sgt;
        buf->vaddr = NULL;
 
@@ -602,6 +629,8 @@ static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
        if (WARN_ON(buf->dma_sgt))
                vb2_dma_sg_unmap_dmabuf(buf);
 
+       iovmm_unmap(buf->dev, buf->iova);
+
        /* detach this attachment */
        dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
        kfree(buf);
@@ -632,6 +661,7 @@ static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
                return dba;
        }
 
+       buf->iova = 0;
        buf->dma_dir = dma_dir;
        buf->size = size;
        buf->db_attach = dba;
@@ -646,6 +676,14 @@ static void *vb2_dma_sg_cookie(void *buf_priv)
        return buf->dma_sgt;
 }
 
+dma_addr_t vb2_dma_sg_plane_dma_addr(struct vb2_buffer *vb,
+                                    unsigned int plane_no)
+{
+       struct vb2_dma_sg_buf *buf = vb->planes[plane_no].mem_priv;
+
+       return buf->iova;
+}
+
 const struct vb2_mem_ops vb2_dma_sg_memops = {
        .alloc          = vb2_dma_sg_alloc,
        .put            = vb2_dma_sg_put,

diff --git a/include/media/videobuf2-dma-sg.h b/include/media/videobuf2-dma-sg.h
index 52afa0e2bb17105f642ac6fcd07355cfa450477a..8175c7204ae5a8c703d73ea400751187f702e3bd 100644 (file)
--- a/include/media/videobuf2-dma-sg.h
+++ b/include/media/videobuf2-dma-sg.h
@@ -21,6 +21,9 @@ static inline struct sg_table *vb2_dma_sg_plane_desc(
        return (struct sg_table *)vb2_plane_cookie(vb, plane_no);
 }
 
+dma_addr_t vb2_dma_sg_plane_dma_addr(struct vb2_buffer *vb,
+                                    unsigned int plane_no);
+
 extern const struct vb2_mem_ops vb2_dma_sg_memops;
 
 #endif