The PCIe spec (r3.0, sec 7.2.2) specifies an "Enhanced Configuration Access
Mechanism" (ECAM) for memory-mapped access to configuration space. ECAM is
required for PCIe systems unless there's a standard firmware interface for
config access.
In the absence of a firmware interface, we use pci_generic_ecam_ops, and on
ACPI systems, we discover the ECAM space via the MCFG table and/or the _CBA
method.
Unfortunately some systems provide MCFG but don't implement ECAM according
to spec, so we need a mechanism for quirks to make those systems work.
Add an MCFG quirk mechanism to override the config accessor functions
and/or the memory-mapped address space.
A quirk is selected if it matches all of the following:
- OEM ID
- OEM Table ID
- OEM Revision
- PCI segment (from _SEG)
- PCI bus number range (from _CRS, wildcard allowed)
If the quirk specifies config accessor functions or a memory-mapped address
range, these override the defaults.
[bhelgaas: changelog, reorder quirk matching, fix oem_revision typo per
Duc, add under #ifdef CONFIG_PCI_QUIRKS]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
Signed-off-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
pci_mcfg_lookup() is the external interface to the generic MCFG code.
Previously it merely looked up the ECAM base address for a given domain and
bus range. We want a way to add MCFG quirks, some of which may require
special config accessors and adjustments to the ECAM address range.
Extend pci_mcfg_lookup() so it can return a pointer to a pci_ecam_ops
structure and a struct resource for the ECAM address space. For now, it
always returns &pci_generic_ecam_ops (the standard accessor) and the
resource described by the MCFG.
No functional changes intended.
[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
On ACPI systems that support memory-mapped config space access, i.e., ECAM,
the PCI Firmware Specification says the OS can learn where the ECAM space
is from either:
- the static MCFG table (for non-hotpluggable bridges), or
- the _CBA method (for hotpluggable bridges)
The current MCFG table handling code cannot be easily generalized owing to
x86-specific quirks, which makes it hard to reuse on other architectures.
Implement generic MCFG handling from scratch, including:
- Simple MCFG table parsing (via pci_mmcfg_late_init() as in current x86)
- MCFG region lookup for a (domain, bus_start, bus_end) tuple
[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
