[media] v4l: videobuf2: add DMA coherent allocator

Add an implementation of DMA coherent memory allocator and handling
routines for videobuf2, implemented on top of dma_alloc_coherent() call.

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 185 insertions, 0 deletions

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c
new file mode 100644
index 000000000000..bb6a5602cf94
--- /dev/null
+++ b/drivers/media/video/videobuf2-dma-contig.c
@@ -0,0 +1,185 @@
+/*
+ * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <p.osciak@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/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 (void *)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");
+MODULE_LICENSE("GPL");