Pci bridge and multi function support

[joevt]

Add PCI bridge and multi-function device support. Overview:

• A multi-function device is two or more PCIDevices with the same device number but one device is function zero (as with currently implemented PCIDevices) and the other functions have function numbers between 1 and 7. The device number and function number are properties of the PCIDevice's parent PCIHost connection.
• A PCIBridge is a PCIHost (it can connect child PCI devices) and a PCIDevice (it has config space, BARs, and expansion ROM).
• A PCIDevice has Type 0 header. It has 6 BARs.
• A PCIBridge has Type 1 header. It has 2 BARs. The config space registers beginning from offset 0x18 differ from those of a PCIDevice.

Possible future modifications:

• Add a PCICardBus class. It is a PCIHost. It has Type 2 header. It has one BAR. The first 20 bytes match Type 0 and Type 1 headers. These exist in New World Macs. They allow hot-plug of PCI devices.
• Split base PCI registers (first 0x10 bytes) into a PCIBase class. Type 1 and 2 have two or one BAR but I think all 6 BARs belong in PCIBase class anyway.
• Split PCIHost into two classes: Currently existing PCIHosts (Bandit, Grackle) are PCIHost and PCIRoot (they get the broadcast I/O functionality) while PCIBridge is PCIHost only.
• pci_register_mmio_region should maybe return a pointer to a region struct so that it can be used for unregistering or modifying the region's range. This may be useful for PCI bridges which have ranges that may constrain memory BARs of their downstream devices.

PCIDevice

• Moved expansion ROM BAR handling to a separate function pci_wr_exp_rom_bar so that it can be used by both PCI devices and PCI bridges which have the ROM BAR in different locations. It now supports unmapping expansion ROM. Also made exp_rom_bar not writable if there's no ROM.
• supports_io_space function now uses a flag has_io_space which is automatically set for PCI bridges or PCI devices that have an I/O BAR.
• Added num_bars field which specifies the number of valid BARs.
• map_exp_rom_mem now properly unmaps expansion ROM (using new function unmap_exp_rom_mem) before mapping it again.
• Added function set_multi_function which modifies hdr_type to indicate if a device has other functions. This is to be applied only to devices with function number 0.
• Added function set_irq_pin. A multi-function device may have functions of the same class (e.g. a USB device with two OHCI functions) but each function should be initialized with a different interrupt pin.

PCIHost

• PCIHosts (bandit and mpc106/grackle) now use device number and function number for identifying attached PCIDevices. A macro DEV_FUN is added to calculate the id. Bandit no longer uses IDSEL. Grackle no longer uses only device number.
• When attaching a PCI device, it will check if it's a multi-function device (there exists an attached function that is not zero) and adjust hdr_type of function 0 of the device accordingly.
• Attached PCI bridges are added to a list of PCI bridges attached to the host.
• Added an overloaded version of attach_pci_device which takes a suffix string that can be used to make a device name unique so that multiple devices of the same class can be added to a machine. The method returns a PCIDevice which can be easily used to attach more PCI devices if it is a PCIHost.
• Added pci_io_read_loop and pci_io_write_loop which loop through attached PCI devices to find one that will perform the action for the given I/O address without logging an error (since some other device might perform the action).
• Added pci_io_read_broadcast and pci_io_write_broadcast which are used by a PCI root (bandit/grackle). They will log an error if the action is not performed.
• pci_find_device (used by PCI root) will recursively find a PCIDevice for type 1 config register accesses.
• Logging from PCIHost now includes the name of the PCIHost instead of just "PCIHost" because there can be multiple PCI hosts.

PCIBridge

• Sets num_bars to 2 and hdr_type to 1.
• I/O ranges set in the config registers are handled correctly by pci_io_read and pci_io_write.
• Memory ranges set in the config registers do not currently affect memory mmio regions. It is assumed that Open Firmware and the OS will set the ranges and BARs correctly to allow all BARs to be accessed fully.

bandit, mpc106

• Bandit and Grackle now call pci_io_read_broadcast and pci_io_write_broadcast to pass I/O accesses to downstream PCI devices.
• Chaos is modified to work like Bandit even though it will never have PCI bridges attached or devices that support I/O accesses. It's simpler this way.

atimach64gx

• Since it doesn't have I/O BARs but does do I/O accesses, it needs to set has_io_space explicitly.

atirage

• Don't log anything if the I/O access is not for this device. A different device might handle it.
• Don't return true for I/O access if an I/O access is not performed. Otherwise the I/O access won't be passed to other devices.

machinecatalyst, machinegossamer, machinetnt

• Use DEV_FUN to attach PCI devices by device number and function number.

grackle.md

• Updated notes about attaching PCI devices to include info about PCI bridges and multi-function devices.

[joevt]

Rebased and ready for merge.

[maximumspatium]

Please remove changes to atimach64gx.cpp - it should be fixed in a separate commit.

[maximumspatium]

It would be helpful to have three commits: 1) PCIBridge 2) multi-function devices 3) documentation update

[joevt]

Rebased and ready for review. First there's a fix for previous merge. Then a fix for ATIRage I/O accesses. Then a preliminary step before the main event. After the main commit is an addition, and a change. Finally, there's a readme update.