On Fri, Jun 10, 2016 at 09:55:18PM +0200, Tomasz Nowicki wrote:
> ACPI spec6.1 - chapter: 5.5.2.4 defines OperationRegion (Declare Operation
> Region). Following the spec: " [...] An Operation Region is a specific
> region of operation within an address space that is declared as a subset
> of the entire address space using a starting address (offset) and a length.
> Control methods must have exclusive access to any address accessed via
> fields declared in Operation Regions. [...]".
>
> OperationRegion allows to declare various of operation region address space
s/of//
> identifiers including PCI_Config. PCI_Config is meant to access PCI
> configuration space from the ASL. So every time ASL opcode operates
> on PCI_Config space region, ASL interpreter dispatches accesses to OS
> low-level calls - raw_pci_write() and raw_pci_read() for Linux - so-called
> ACPI RAW accessors.
>
> In order to support PCI_Config operation region, implement mentioned
> raw_pci_write() and raw_pci_read() calls so they find associated bus
> and call read/write ops.
>
> Waiting for clarification in the ACPI specifications in relation
> to PCI_Config space handling before PCI bus enumeration is completed,
> current code does not support PCI_Config region accesses before PCI bus
> enumeration whilst providing full AML PCI_Config access availability
> when the PCI bus enumeration is completed by the kernel so that
> RAW accessors can look-up PCI operations through the struct pci_bus
> associated with a PCI bus.
>
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> Signed-off-by: Jayachandran C <jchandra@xxxxxxxxxxxx>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> ---
> arch/arm64/kernel/pci.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index b3b8a2c..328f857 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -71,13 +71,21 @@ int pcibios_alloc_irq(struct pci_dev *dev)
> int raw_pci_read(unsigned int domain, unsigned int bus,
> unsigned int devfn, int reg, int len, u32 *val)
> {
> - return -ENXIO;
> + struct pci_bus *b = pci_find_bus(domain, bus);
> +
> + if (!b)
> + return PCIBIOS_DEVICE_NOT_FOUND;
> + return b->ops->read(b, devfn, reg, len, val);
> }
>
> int raw_pci_write(unsigned int domain, unsigned int bus,
> unsigned int devfn, int reg, int len, u32 val)
> {
> - return -ENXIO;
> + struct pci_bus *b = pci_find_bus(domain, bus);
> +
> + if (!b)
> + return PCIBIOS_DEVICE_NOT_FOUND;
> + return b->ops->write(b, devfn, reg, len, val);
> }
>
> #ifdef CONFIG_NUMA
> --
> 1.9.1
>
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