[QUESTION]: Same IO bus address in different _CRS methods

* [QUESTION]: Same IO bus address in different _CRS methods
@ 2017-03-09 15:41 Gabriele Paoloni
  2017-03-09 18:11 ` Bjorn Helgaas
  0 siblings, 1 reply; 8+ messages in thread
From: Gabriele Paoloni @ 2017-03-09 15:41 UTC (permalink / raw)
  To: Bjorn Helgaas
  Cc: Tomasz Nowicki, Lorenzo Pieralisi, arnd, agraf, Yuanzhichang,
	xuwei (O),
	John Garry, linux-pci, linux-acpi

Hi Bjorn and all

I have a question regarding bus addresses for IO resources in the ACPI table.

The question is if from an ACPI perspective it is legal to have two entries in
separate _CRS methods using the same IO bus address.

As an example please see the code at the bottom: we have the same bus address
starting at 0x0 with (obviously) different offsets leading to different CPU
physical addresses. Is this legal?

p.s. full DSDT is here:
https://git.linaro.org/people/heyi.guo/OpenPlatformPkg.git/tree/Chips/Hisilicon/Hi1610/Hi1610AcpiTables/Dsdt/D03Pci.asl?h=estuary-rp

Many thanks
Gab

----

  Device (PCI0)
  {
    Name (_HID, "HISI0080") // PCI Express Root Bridge
    Name (_CID, "PNP0A03") // Compatible PCI Root Bridge
    Name(_SEG, 0) // Segment of this Root complex
    Name(_BBN, 0) // Base Bus Number
    Name(_CCA, 1)
    Method (_CRS, 0, Serialized) { // Root complex resources

[...]

        QWordIO (
          ResourceProducer,
          MinFixed,
          MaxFixed,
          PosDecode,
          EntireRange,
          0x0, // Granularity
          0x0, // Min Base Address
          0xffff, // Max Base Address
          0xb7ff0000, // Translate
          0x10000 // Length
        )
      }) // Name(RBUF)
      Return (RBUF)
    } // Method(_CRS)

// PCIe Root bus
  Device (PCI1)
  {
    Name (_HID, "HISI0080") // PCI Express Root Bridge
    Name (_CID, "PNP0A03") // Compatible PCI Root Bridge
    Name(_SEG, 1) // Segment of this Root complex
    Name(_BBN, 0xe0) // Base Bus Number
    Name(_CCA, 1)
    Method (_CRS, 0, Serialized) { // Root complex resources

[...]

        QWordIO (
          ResourceProducer,
          MinFixed,
          MaxFixed,
          PosDecode,
          EntireRange,
          0x0, // Granularity
          0x0, // Min Base Address
          0xffff, // Max Base Address
          0xbdff0000, // Translate
          0x10000 // Length
        )
      }) // Name(RBUF)
      Return (RBUF)
    } // Method(_CRS)

^ permalink raw reply	[flat|nested] 8+ messages in thread