[PATCH] PowerPC: Fix PCI I/O ports allocation

[Aurelien Jarno]

Long story, small patch...

On the PowerPC target, the PCI devices using I/O ports are currently not
working correctly with a relatively old kernel (<= 2.6.24). This is due
to the assignation of I/O port 0, while the I/O ports start at 1, which
keeps the device disabled. Recent version of Linux assign resources to
those devices, that's why the problem wasn't present on those versions.

Moreover the QEMU OldWorld machine have a few devices mapped on fixed
I/O ports, that should be skipped when assigning I/O ports to PCI 
devices. Those devices are:
- video card (0x3c0-0x3cf, 0x3b4-0x3b5, 0x3ba, 0x1ce-0x1cf, 0x1d0-0x1d1)
- i8259 (0x20-0x21, 0xa0-0x1a, 0x4d0-0x4d1)
- m48t59 (0x74-0x79)
- OpenBIOS debug port (0xf00-0xf03)

Given that ranges, I have decided to start mapping PCI I/O ports at
0x1000. Note that real G3 beige starts to map them at 0x400. This can be
changed later, when we get rid of the i8259 and m48t59 and if we move
the OpenBIOS debug port.

I have done this change unconditionally because Sparc also have the
problem, though the first I/O port can be chosen differently.

Index: drivers/pci.c
===================================================================
--- drivers/pci.c	(révision 411)
+++ drivers/pci.c	(copie de travail)
@@ -760,7 +760,8 @@
    /* Find all PCI bridges */

mem_base = arch->mem_base;
-	io_base = arch->io_base;
+	/* I/O ports under 0x1000 are used by devices mapped at fixed location. */
+	io_base = arch->io_base + 0x1000;
    path = strdup("");
    for (bus = 0; bus<0x100; bus++) {
    	ob_scan_pci_bus(bus, &mem_base, &io_base, &path);

[Aurelien Jarno]

On Fri, Jan 16, 2009 at 03:05:30AM +0100, Aurelien Jarno wrote:
> Long story, small patch...
>
> On the PowerPC target, the PCI devices using I/O ports are currently not
> working correctly with a relatively old kernel (<= 2.6.24). This is due
> to the assignation of I/O port 0, while the I/O ports start at 1, which
> keeps the device disabled. Recent version of Linux assign resources to
> those devices, that's why the problem wasn't present on those versions.
>
> Moreover the QEMU OldWorld machine have a few devices mapped on fixed
> I/O ports, that should be skipped when assigning I/O ports to PCI 
> devices. Those devices are:
> video card (0x3c0-0x3cf, 0x3b4-0x3b5, 0x3ba, 0x1ce-0x1cf, 0x1d0-0x1d1)
> i8259 (0x20-0x21, 0xa0-0x1a, 0x4d0-0x4d1)
> m48t59 (0x74-0x79)
> OpenBIOS debug port (0xf00-0xf03)

I have removed the firmware debug and the i8259 from the current SVN.
> Given that ranges, I have decided to start mapping PCI I/O ports at
> 0x1000. Note that real G3 beige starts to map them at 0x400. This can be
> changed later, when we get rid of the i8259 and m48t59 and if we move
> the OpenBIOS debug port.

We can now move the start of the mapping to 0x400.
> I have done this change unconditionally because Sparc also have the
> problem, though the first I/O port can be chosen differently.
> Index: drivers/pci.c
>
> --- drivers/pci.c	(révision 411)
> +++ drivers/pci.c	(copie de travail)
> @@ -760,7 +760,8 @@
>    /* Find all PCI bridges */
>
> mem_base = arch->mem_base;
> io_base = arch->io_base;
> /* I/O ports under 0x1000 are used by devices mapped at fixed location. */
> io_base = arch->io_base + 0x1000;
> path = strdup("");
> for (bus = 0; bus<0x100; bus++) {
> ob_scan_pci_bus(bus, &mem_base, &io_base, &path);

[Blue Swirl]

On 1/16/09, Aurelien Jarno  wrote:
> On Fri, Jan 16, 2009 at 03:05:30AM +0100, Aurelien Jarno wrote:
> > Long story, small patch...
> >
> > On the PowerPC target, the PCI devices using I/O ports are currently not
> > working correctly with a relatively old kernel (<= 2.6.24). This is due
> > to the assignation of I/O port 0, while the I/O ports start at 1, which
> > keeps the device disabled. Recent version of Linux assign resources to
> > those devices, that's why the problem wasn't present on those versions.
> >
> > Moreover the QEMU OldWorld machine have a few devices mapped on fixed
> > I/O ports, that should be skipped when assigning I/O ports to PCI
> > devices. Those devices are:
> > video card (0x3c0-0x3cf, 0x3b4-0x3b5, 0x3ba, 0x1ce-0x1cf, 0x1d0-0x1d1)
> > i8259 (0x20-0x21, 0xa0-0x1a, 0x4d0-0x4d1)
> > m48t59 (0x74-0x79)
> > OpenBIOS debug port (0xf00-0xf03)
>
> I have removed the firmware debug and the i8259 from the current SVN.
> > Given that ranges, I have decided to start mapping PCI I/O ports at
> > 0x1000. Note that real G3 beige starts to map them at 0x400. This can be
> > changed later, when we get rid of the i8259 and m48t59 and if we move
> > the OpenBIOS debug port.
>
> We can now move the start of the mapping to 0x400.
> > I have done this change unconditionally because Sparc also have the
> > problem, though the first I/O port can be chosen differently.

It also works for Sparc64. I committed it with 0x400, thanks.