Oh my question contains discrepancy.
My real question is whether the output of ioport_map is physical or virtual.
(I'm confused)
I know for systems with memory mapped I/O, we can just use
request_mem_region, ioremap (maps to virtual address), plain memory access
for the peripheral. (the page table sets the area as uncacheable because
it's IO devices)
Thanks!
Chan Kim
From: c...@etri.re.kr
Sent: Monday, March 22, 2021 10:28 AM
To: kernelnewbies@kernelnewbies.org
Subject: question about ioport_map function
Hello all
>From what I understand, to map io ports to virtual memory, we should use
request_region, ioport_map/unmap and ioread/write functions.
These are for architectures having input, output machine instructions like
x86, x86_64.
And the return address of ioport_map is physical address.
Is my understanding correct?
Thanks!
Chan Kim
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