Hello,
I am having some problems with the initialization of BAR registers of
the PCI bus. I have a number of devices connected to the bus, which have
a BAR-size of less than PAGE_SIZE. For example:
01:00.0 Network controller: VMIC: Unknown device 5565 (rev 01)
Subsystem: PLX Technology, Inc.: Unknown device 9656
Flags: bus master, 66Mhz, medium devsel, latency 128, IRQ 52
Memory at 00000000dfeffe00 (32-bit, non-prefetchable) [size=512]
I/O ports at e0ffff00 [size=256]
Memory at 00000000dfeffdc0 (32-bit, non-prefetchable) [size=64]
Memory at 00000000d8000000 (32-bit, non-prefetchable) [size=64M]
Capabilities: [40] Power Management version 0
Capabilities: [48] #00 [0080]
I want to access the PCI-areas from from user space, so I try to do an
mmap. The returned address is however rounded to multiple of PAGE_SIZE
(=0x1000). To access for example BAR0, I have to use the return-value
from mmap+0xE00. And in the above case, I am able to access the BAR0 and
BAR2 areas with only 1 mmap cal, as the 2 addresses are within one page.
The problem is that, when running my code on a I386 platform the BAR
registers are mapped at address 0x0 of the returned area.
When looking at the PCI init code (arch/ppc/syslib/pci_auto.c) I see
that the BAR-base address and/or size is not corrected for PAGE_SIZE. Is
this correct behaviour?
I could image the following line being changed from:
bar_value = (*upper_limit - bar_size) & ~(bar_size - 1);
to:
bar_value = ((*upper_limit - bar_size) & ~(bar_size - 1)) &
~(PAGE_SIZE-1);
The PCI area is assigned using a top-down method. Using this statement
the bar_value is rounded down to the first PAGE_SIZE boundary.
This gives the following output:
01:00.0 Network controller: VMIC: Unknown device 5565 (rev 01)
Subsystem: PLX Technology, Inc.: Unknown device 9656
Flags: bus master, 66Mhz, medium devsel, latency 128, IRQ 52
Memory at 00000000dfeff000 (32-bit, non-prefetchable) [size=512]
I/O ports at e0fff000 [size=256]
Memory at 00000000dfefe000 (32-bit, non-prefetchable) [size=64]
Memory at 00000000d8000000 (32-bit, non-prefetchable) [size=64M]
Capabilities: [40] Power Management version 0
Capabilities: [48] #00 [0080]
Kind regards,
Johan Borkhuis
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