On 07/22/2015 02:14 AM, Lorenzo Pieralisi wrote:
Bjorn, Guenter,
On Thu, Jul 09, 2015 at 11:59:16AM +0100, Lorenzo Pieralisi wrote:
When a PCI bus is scanned, upon PCI bridge detection the kernel
has to read the bridge registers to set-up its resources so that
the PCI resource hierarchy can be validated properly.
Most if not all architectures read PCI bridge registers in the
pcibios_fixup_bus hook, that is called by the PCI generic layer
whenever a PCI bus is scanned.
Since pci_read_bridge_bases is an arch agnostic operation (and it
is carried out on all architectures) it can be moved to the generic
PCI layer in order to consolidate code and remove the respective
calls from the architectures back-ends.
The PCI_PROBE_ONLY flag is not checked before calling
pci_read_bridge_buses in the generic layer since reading the bridge
bases is not related to resources assignment; this implies that it
can be carried out safely on PCI_PROBE_ONLY systems too and should
not affect architectures (alpha, mips) that check the PCI_PROBE_ONLY
flag before reading the bridge bases.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: James E.J. Bottomley <jejb@xxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Michal Simek <monstr@xxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
---
v2->v3:
- Dropped RFC status
- Removed bridge resources claiming from pci_read_bridge_bases()
What do you want me to do with this patch ? I removed the resource
claiming - ie the only controversial bit, I can only test on
arm64, I would like to make some progress on this otherwise
I will have to add the bridge bases read to arm64 pcibios_fixup_bus()
and be done with this.
Lorenzo,
please give me a few days to test it. I was out on vacation for
the last two weeks, and I am still struggling to get my test systems
back to a working state.
Thanks,
Guenter
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