Dear Jason Gunthorpe, On Tue, 29 Jan 2013 21:56:55 -0700, Jason Gunthorpe wrote: > However, Thomas how did you recover the high bits of the > IO window address from the bridge configuration? Are you reading the > struct resource directly? That probably causes problems with > hotplug/etc... The PCI-to-PCI bridge configuration space has a register with the high bits of the I/O window address. If you look at the PCI-to-PCI emulation code, I set the bit that says "I'm a bridge capable of 32 bits addressing of I/O addresses", and then when setting up the windows, I reconstruct the full 32 bits address by reading the two I/O address registers. See 3.2.5.6 in the PCI-to-PCI bridge specification: If the low four bits of the I/O Base and I/O Limit registers are 01h, then the bridge supports 32-bit I/O address decoding, and the I/O Base Upper 16 Bits and the I/O Limit Upper 16 Bits hold the upper 16 bits, corresponding to AD[31::16], of the 32-bit I/O Base and I/O Limit addresses respectively. In this case, system configuration software is permitted to locate the I/O address range supported by the anywhere in the 4-GB I/O Space. Note that the 4-KB alignment and granularity restrictions still apply when the bridge supports 32 -bit I/O addressing. (And my code does ensure that the low four bits of the I/O Base and I/O Limit registers are 01h) Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- 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
