Subject: Item #414: PCI-IDE device binding (overview)
Date: Tue, 8 Jul 97 13:51:14 -0700
From: <ron@apple.com>

P1275 Open Firmware Working Group Proposal -- Proposal #414 Ver 1

Title:          PCI-IDE Device Binding

Author:         Ron Hochsprung

Date:           7/7/97

Ed/Tech:        Technical

Synopsis:       Document PCI-IDE representation for CHRP

Doc & Version:  New Device Binding??

Problem:        PCI-IDE representation is undocumented

Rationale:

The current CHRP and/or device bindings do not document how the PCI-IDE
device is to be represented in the device tree.

Proposal:

Note:  this is not yet a complete proposal, but sketches the overall 
representational issues related to PCI-IDE.

    The PCI-IDE device that is required by Chapter 11 of <i>PowerPC
    Microprossor Common Hardware Reference Platform: I/O Device
    Reference</i> shall be represented in the Open Firmware device
    tree as follows:
    
    The PCI-IDE controller node <i>shall</i> be a child of a "pci"
    bridge.  Its "name" and "device_type" values <i>shall</i> be
    "pci-ide".  Its "reg" property <i>shall</i> consist of 6
    entries, where the first entry is its config address, and the
    next 2 represent the command block and control block addresses,
    respectively, of its primary controller, the next 2 represent
    the command block and control block addresses, respectively, of
    its secondary controller and the last entry represents the
    address of its bus-master controller.
    
    The "pci-ide" node <i>shall</i> contain a "#address-cells"
    property with a value of 1 and a "#size-cells" property with a
    value of 0.  This denotes that the child nodes are enumerated.
    
    The child nodes of a "pci-ide" node <i>shall</i> have the "name"
    and "device-type" of "ide".  The "ide" node with the "reg" value
    of 0 is the primary IDE bus, while the "ide" node whose "reg" is
    1 is the secondary IDE bus.  The "ide" nodes shall
    "#address-cells" and "#size-cells" properties with values of 1
    and 0, respectively.  This denotes that their children are
    enumerated.
    
    The child nodes of the "ide" bus nodes represent actual devices,
    typically hard disks and CD-ROMs.  The child devices
    <i>shall</i> be probed and shall be created if found present.
    Hard drives <i>shall</i> be named "disk" and CD-ROMs
    <i>shall</i> be named "cdrom";  both disk and cdrom devices
    shall have a "device_type" of "block".  The "reg" property of
    these nodes <i>shall</i> be 0 for master devices and 1 for
    slaves.
    
    An example sub-tree for the "pci-ide" sub-system is:
    
        pci-ide@b,1
            ide@0
                disk@0
            ide@1
                cdrom@0

[ P1275 Item #414 -- Received: Tue Jul  8 13:51:26 PDT 1997 ]