[Ilugc] doubts in kernel porting & device drivers
- From: cyborg4k@xxxxxxxxx (Shakthi Kannan)
- Date: Wed Jan 19 13:12:00 2005
Hi Madhukar,
--- Madhukar mythri <madhukar_linux@xxxxxxxxxxx>
wrote:
Memory mapped mean.. the IO-address lines is
mapped
to physical memory location some range....
Address lines (from CPU) are mapped to I/O, eventually
using the addressable memory region. Have to use
readl(), writel() functions.
and IO-mapped mean CPU bus lines are dedicated to
some
IO's which have smaller address range...
Few address lines from CPU are used just for I/O chip
select. As a result you have to use specific inb(),
outb() functions.
/* ioremap MMIO region */
ioaddr = ioremap(iom_start, iom_len);
//
What type is ioaddr? iom_len?
ioaddr------> void *
iom_len----->unsigned long
ioaddr should be of type - unsigned long.
K Shakthi
=====
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K Shakthi
Specsoft (Hexaware Technologies), ASIC Design Center
http://www.geocities.com/shakthimaan
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