What's the difference between ioremap and file operation mmap?

I'm currently working on a PCI device driver for Ubuntu. I have some example code about PCI driver, but I have difficult on understanding the ioremap and file_operation.mmap. The description of file operation mmap: Memory mapping is one of the most interesting features of modern Unix systems. As far as drivers are concerned, memory mapping can be implemented to provide user programs with direct ac

[zyxwv]

ioremap は IO mapped memory。デバイスを IO メモリ空間に割り当てる。mmap は memory mapped IO。ファイルディスクリプタをメモリアドレス空間に割り当てる。