dmabuf

This is a kernel driver that allows to allocate buffer that can be used for DMA and mapped to user space.

The buffer consist of smaller contiguous entries of up to 4 MB in size that are allocated with dma_alloc_coherent. The buffer can be mapped to user space through mmap where each contiguous entry is mapped with remap_pfn_range.

Buffer de/allocation and stub implementations of fops (mmap, llseek, read and write) can be found in dmabuf.h.

The rest of the code implements the driver:

• chrdev.h - char device handling (de/allocation)
• dmabuf_fops.h - impl char device fops using stubs (from dmabuf.h)
• dmabuf_platform_device.h - dummy device
• dmabuf_platform_driver.h - driver probe (set DMA mask and create misc device)