/*
 * - Function ----------------------------------------------------------------
 *
 *  sentric_fpga_mmap
 *
 *      This function maps the FPGA register block to user space.
 *
 *  Parameters:
 *      filep           Pointer to file struct for this device.
 *      vma             Pointer to the virtual memory area struct to map to.
 *
 *  Returns:
 *      0 success, -ve number is an error code.
 *
 *  Notes:
 *      None.
 * ---------------------------------------------------------------------------
 */
int
sentric_fpga_mmap(struct file *filep, struct vm_area_struct *vma)
{
    unsigned long off;
    phys_addr_t phys;
    unsigned long vsize, psize;

    /* Convert requested offset in units of pages to bytes */
    /* This is the offset from base of FPGA regs region, should always be 0 */
    off = vma->vm_pgoff << PAGE_SHIFT;

    /* physical address */
    phys = SENTRIC_FPGA_ADDR;

    /* Check that the user hasn't asked for more than is available */
    vsize = vma->vm_end - vma->vm_start;
    psize = PAGE_SIZE - off;
    if (vsize > psize) {
        printk("sentric_fpga:mmap: requested too much i/o space: %ld\n", vsize);
        return -EINVAL;
    }

    /* Use non-cached accesses as this is shared-memory */
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    /* Don't try to swap out physical pages.. */
    vma->vm_flags |= VM_RESERVED;

    /* Don't dump addresses that are not real memory to a core file. */
    vma->vm_flags |= VM_IO;

    if (io_remap_page_range64(vma->vm_start, phys, vsize, vma->vm_page_prot)) {
        return -EAGAIN;
    }

    return 0;
} /* sentric_fpga_mmap() */