Hello, I want to use DMA from userspace. I already use dma in kernel, and now I want can create a character device which will be responsible for this. The only problem is that I want to use the same memory which was allocated in kernel with dma_alloc_coherent. Is it correct to use mmap in order to use the phsyical memory which was allocated with dma_alloc_coherent ? If it's that simple it can be surely helpful, and the simple driver which wraps dma_alloc_coherent can do the job for dmaing from userspace. In kernel: dma_buffer_info->buf_info[i].virtAddr = (uint8_t *)dma_alloc_coherent( &ti667x_pci_dev[dev_id]->dev, dma_buffer_info->buffer_size, (dma_addr_t *)&dma_buffer_info->buf_info[i].pcieAddr, GFP_KERNEL); In userspace: buf_desc[i].virtAddr = mmap(0, size_of_buffer, PROT_READ | PROT_WRITE, MAP_SHARED, pcie_drv_inst[dsp_id].dev_desc, buf_desc[i].pcieAddr); Thanks, Ran