On Thu, 2005-03-31 at 11:07, nobin matthew wrote:
> Dear Friends,
>
> Can anybody Help me in this Pc104 driver Problem;
> What is the basics steps in doing read and write on
> Pc104 cards.
>
> Deatails Given Below:
> I am writing a Linux device driver for
> Diamond systems
> IR104 digital IO card. This is a PC104 bus device(that
> means it ISA
> bus compatible).
> The Platform is Arcom Viper borad(with support for
> PC104), This is a
> Xscale, Little endian Platform.
>
> The Specification of PC104 interface given in Viper
> borad manual is:
> 0x3C000000-0x3CFFFFFF PC/104 memory space(16MB)
> 0x30000000-0x300003FF PC/104 IO space(1KB)
>
> Specification given in IR104 manual is:
> I made the jumber setting so that, the IO space
> addresses taken by 8
> registers will be 0x300-0x307
>
> The driver should do read and write on this
> registers(character device
> driver).
>
> I took two approaches one is:
> i added IO space and 0x300, did inb() and oub().(IO
> space base address
> and 0x300)
> otherway i did ioremap on added result, did inb() and
> oub().
/* Remap a not (necessarily) aligned port region */
void *short_remap(unsigned long phys_addr)
{
/* The code comes mainly from arch/any/mm/ioremap.c */
unsigned long offset, last_addr, size;
last_addr = phys_addr + SHORT_NR_PORTS - 1;
offset = phys_addr & ~PAGE_MASK;
/* Adjust the begin and end to remap a full page */
phys_addr &= PAGE_MASK;
size = PAGE_ALIGN(last_addr) - phys_addr;
return ioremap(phys_addr, size) + offset;
}
/* Unmap a region obtained with short_remap */
void short_unmap(void *virt_add)
{
iounmap((void *)((unsigned long)virt_add & PAGE_MASK));
}
>
> In the second method:
> I did same procedures using IO memory space
Here Use ioremap to get a base address in the
region(0x3C000000-0x3CFFFFFF).
Suppose ISA_BEGIN = 0x3C000000, ISA_END = 0x3CFFFFFF
void *base;
base = ioremap(ISA_BEGIN, ISA_END - ISA_BEGIN);
base = base - ISA_BEGIN; /* offset */
Use these base address to read and write the IO region.
For more details go to http://www.xml.com/ldd/chapter/book/ch08.html
to get more info.
>
> both methods are giving errors, i think that is
> related to paging. i think
> there is a need for disabling paging in this space.
>
> Please help regarding this. How to solve this.
>
> Nobin Mathew
>
>
>
>
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