Re: PCI and ioports question

From: Richard B. Johnson (
Date: Tue Jul 17 2001 - 11:47:04 EST

On Tue, 17 Jul 2001, daniel sheltraw wrote:

> Hello Kernel listees
> I have a question about ioports on PCI devices but first: If
> there is a better mailing list for asking these types of questions
> would you kindly direct me there.
> The question is this. When do I need to use ioremap for ioports
> on a PCI device (PC architecture)? Is the answer: always except
> when the physical address is within the 64K - 1M ISA region (legacy
> ports).
> Thanks,
> Daniel

For PORTS, you use check_region(). If the result is non-zero, there
is a conflict. To get the region, use request_region(). ioremap()
is for memory address-space.

Ports only go from 0 to 0xffff on an Intel machine, even if the
device is on the PCI bus.

cat /dev/ioports
0000-001f : dma1
0020-003f : pic1
0040-005f : timer
0060-006f : keyboard
0070-007f : rtc
0080-008f : dma page reg
00a0-00bf : pic2
00c0-00df : dma2
00f0-00ff : fpu
02f8-02ff : serial(auto)
03c0-03df : vga+
03f8-03ff : serial(auto)
0cf8-0cff : PCI conf1
b400-b403 : PCI device 104b:1040
  b400-b403 : BusLogic BT-958
b800-b87f : PCI device 10b7:9055
  b800-b87f : eth0
d000-d01f : PCI device 1022:2000
d400-d41f : PCI device 8086:7112
d800-d80f : PCI device 8086:7111
e400-e43f : PCI device 8086:7113
e800-e81f : PCI device 8086:7113

Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).

    I was going to compile a list of innovations that could be
    attributed to Microsoft. Once I realized that Ctrl-Alt-Del
    was handled in the BIOS, I found that there aren't any.

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This archive was generated by hypermail 2b29 : Mon Jul 23 2001 - 21:00:09 EST