ioremap is only needed on the linux side for portability with non x86
PCs for PCI devices not in 640k-1MB (Linux kernel I/O space). It causes
Linux to create a table of memory offsets and regions (a map) for
translating between the two. ioremap will ignore attempts to remap
lower PCI/ISA space (640k-1MB) by returning the virtual address when
given the physical address.
On the RTL side find out the physical address and in x86 use
inb/inw/outb/outw directly for low level single memory accesses. To do
large transfers setup a DMA channel by using linux/kernel/dma.c. dma.c
is only four pages long so the porting effort to RTL should be minimal.
- Kal.
Tomasz Motylewski wrote:
>
> Depending on the version of the kernel ioremap function may be involved as
> well (question to all: is ioremap required/allowed for low ISA memory
> mapped?).
>
> --
> Tomek
>
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