[CC'ing this to Rui Paulo since he tried to help me a while ago]
I have written a driver that is a child of hostb (similar to agp) for
RELENG_7. However, on some chipsets (e.g. i975) it has to read some
memory locations (not pci configuration space) which were registered
by acpi as system resources.
Since my driver is a child of hostb0, I have no idea of how to access
this memory area. Here is a devinfo -r to make things clear:
nexus0
acpi0
Interrupt request lines:
9
I/O ports:
0x10-0x1f
0x22-0x3f
...
0x800-0x87f
I/O memory addresses:
0xc-0xd
0xe-0xf
0xf000-0xf3ff
0xfec0-0xfec00fff
0xfed13000-0xfed19fff --- the memory needed
0xfed1c000-0xfed1
0xfed2-0xfed3
0xfff0-0x
cpu0
coretemp0
acpi_throttle0
ACPI I/O ports:
0x810-0x813
cpufreq0
cpu1
coretemp1
pcib0
pci0
I/O ports:
0x170-0x177
0x376
hostb0
I/O memory addresses:
0xe400-0xe7ff
MYDRIVER0 --- my driver
agp0
pcib1
pci7
vgapci0
Interrupt request lines:
16
I had the same problem under RELENG_6 six month ago which could be
solved by a bus_set_resource() but since the driver now attaches to
hostb, this is not possible anymore.
Earlier, I was given the hint to attach as a child of acpi (see the
old mail attached below) but in this case I didn't have access to the
hostb registers which I need as well.
The only thing I see is: Attach two drivers -- one as child of acpi
and another as child of hostb and let them communicate somehow (no
idea how to do this).
I have also done crazy things like searching for acpi0 and trying
to bus_alloc_resource() the memory I am interested in but this also
failed.
Or is it possible to free(!) somehow the address space from acpi0
and pass it to hostb0 so I can bus_alloc_resource() it?
Thanks a lot for all ideas,
-Andre
--
Hello all,
I am writing a driver which needs to access memory at a
specific location. The location depends on what the BIOS
has configured into the host bridge. For example, my
current machine uses an Intel 975X chipset and the memory
location I am interested in has been set to 0xFED14000 and
is 16KB in size (this is MCHBAR of the 975X memory hub).
You probably just need to do something like:
rid = PCI_BAR(number);
res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, rid, RF_ACTIVE);
And then,
bus_read_4(res, offset from specified PCI BAR);
I have no idea how to access this space from my driver.
I have played around with bus_alloc_resource() but this
only gives me back NULL.
However, a devinfo -r gives me:
nexus0
npx0
acpi0
Interrupt request lines:
9
I/O ports:
0x10-0x1f
...
0x800-0x87f
I/O memory addresses:
0x0-0x9
0xc-0xd
0xe-0xf
0x10-0x7fff
0xf000-0xf3ff
0xfec0-0xfec00fff
0xfed13000-0xfed19fff---
0xfed1c000-0xfed1
0xfed2-0xfed3
0xfed5-0xfed8
0xfee0-0xfee00fff
0xffb0-0xffbf
0xfff0-0x
cpu0
...
The line marked with --- shows the range which includes
the location I am interested in. It is probably assigned
to the acpi0 device.
How do I proceed from this? Do I have to hack around in
the ACPI-Code? I don't hope so ;-)
You'll probably need to create a fake ACPI child driver to access it.
Create your identify routine with something like:
static void mydriver_identify(driver_t *driver, device_t parent)
{
if (device_find_child(parent, mydriver, -1) == NULL
mydriver_match(parent))
device_add_child(parent, mydriver, -1);
}
mydriver_match() should check if you were given the acpi0 device.
Regards,
--
Rui Paulo
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