On 07/14/2015 09:29 AM, Will Deacon wrote:
On Tue, Jul 14, 2015 at 05:12:57PM +0100, David Daney wrote:
On 07/14/2015 04:00 AM, Will Deacon wrote:
On Mon, Jul 13, 2015 at 10:31:36PM +0100, David Daney wrote:
From: David Daney <[email protected]>
Needed to make pci_iomap() work.
Care to elaborate?
I should have explained what I am doing here a little better.
Yeah, thanks.
Systems based on the Cavium ThunderX processor may have up to 8
independent PCIe root complexes. The I/O space on each bus occupies an
independent physical address window.
Hmm, so do you have 64k of I/O space per-bus? That gives 8x256x64k = 128M
IIUC, so not sure what your 32MB is for.
I don't understand where your 256 came from there.
Actually, my current implementation has 1M per bus(which is overkill).
For 8 buses I need 8M, which fits within the PCI_IO_SIZE...
So, in order to be able to map all of these (semi) contiguously, we need
a lot more virtual address space than is supplied by the default values
for all these constants.
The option I chose here was to unconditionally expand the I/O ranges for
all arm64 systems. If you think this breaks existing systems/drivers, I
will have to look for other options.
Hmm, but pci_iomap winds up calling __pci_ioport_map, which expands to
ioport_map which just does:
return PCI_IOBASE + (port & IO_SPACE_LIMIT);
so I'm struggling to see what your patch achieves.
Here is ioport_map (from lib/iomap.c):
void __iomem *ioport_map(unsigned long port, unsigned int nr)
{
if (port > PIO_MASK)
return NULL;
return (void __iomem *) (unsigned long) (port + PIO_OFFSET);
}
With the default value of PIO_MASK (64K), I cannot map any I/O ports on
my PCIe RC 1..7
The values I supplied in my patch may be sub-optimal, but I think
something is needed. I will look into this in a little more detail today.
Thanks,
David Daney
Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
