On Tue, Oct 21, 2003 at 02:24:19PM +0200, Erez Doron wrote:
> afaik, /proc/bus/pci/XX/YY is configuration space and not memory space
it is configuration space when you read/write it and memory space when you
mmap it. Look up the implementation of mmap for this file in kernel
(drivers/pci/proc.c)
Newest XFree86 uses this method instead of /dev/mem.
>
> also:
> dd if=/dev/mem skip=<physical adress> bs=4 count=1 of=<filename>
> does not generate any read cycle to my pci card
You can't reach PCI address space by reading /dev/mem. Look at
drivers/char/mem.c:read_mem
/*
* This funcion reads the *physical* memory. The f_pos points directly to the
* memory location.
*/
static ssize_t read_mem(struct file * file, char * buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
unsigned long end_mem;
ssize_t read;
end_mem = __pa(high_memory);
if (p >= end_mem)
return 0;
^^^^^^^^^^^^^^^^^
>
> cheers,
> erez.
>
>
> Gleb Natapov wrote:
>
> >Hello,
> >
> >On Tue, Oct 21, 2003 at 10:53:54AM +0200, Erez Doron wrote:
> >
> >
> >>o.k., here is the story:
> >>
> >>we are developping a uwb (ultra wide band) network chip.
> >>this should be a wireless 100-500 Mbps with Qos communication chip. (
> >>bluetooth and WiFi, beware ;-)
> >>
> >>the prototype i am working on has it's registers and rams mapped as
> >>memory on a PCI card.
> >>
> >>i tried using /dev/mem to access it, but it didn't work.
> >>so i tried looking at examples and builded my own driver.
> >>
> >>
> >The new way of doing it from userspace is by mmapping /proc/bus/pci/XX/YY
> >AFAIK, but /dev/mem
> >works for me. You must be doing something wrong.
> >
> >--
> > Gleb.
> >
> >
>
>
>
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--
Gleb.
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