Re: [PATCH v2 0/2] PCI: Add support for PCI Enhanced Allocation "BARs"

On Wed, Sep 23, 2015 at 04:26:56PM -0700, Yinghai Lu wrote:

On Wed, Sep 23, 2015 at 3:27 PM, Sean O. Stalley [off-list ref] wrote:

quoted

PCI Enhanced Allocation is a new method of allocating MMIO & IO
resources for PCI devices & bridges. It can be used instead
of the traditional PCI method of using BARs.

EA entries are hardware-initialized to a fixed address.
Unlike BARs, regions described by EA are cannot be moved.
Because of this, only devices which are permanently connected to
the PCI bus can use EA. A removable PCI card must not use EA.

As it is fixed, can you put IORESOURCE_PCI_FIXED in the res->flags?

Thanks

Yinghai

IORESOURCE_PCI_FIXED is set in pci_ea_set_flags():
 
	+static unsigned long pci_ea_set_flags(struct pci_dev *dev, u8 prop)
	+{
	+	unsigned long flags = IORESOURCE_PCI_FIXED;
	+
	+

Which is called in pci_ea_read(), and passed to res->flags (if there aren't any errors):

	+
	+	/* Try to use primary properties, otherwise fall back to secondary */
	+	flags = pci_ea_set_flags(dev, PCI_EA_PP(dw0));
	+	if (!flags)
	+		flags = pci_ea_set_flags(dev, PCI_EA_SP(dw0));
	+

	...

	+	res->flags = flags;


-Sean