On 06/09/2015 02:01 AM, 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. In order to validate the resource hierarchy as soon as the resources themselves are probed (ie read from the bridge), this patch also adds code to pci_read_bridge_bases that claims the bridge resources, so that they are validated and inserted in the resource hierarchy as soon as the bridge bases are probed. 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>
Working fine on powerpc (tested with Freescale P2020 and P5020) as well as x86 (tested on two different server class systems). Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
