Nightloader/i386/docs/drivers/interfaces/pci.md

Driver Definition | PCI

Functions

Category	Function	Function Name
0x10	0x00	init_driver
0x10	0x01	reset_driver
0x10	0x02	cleanup_driver
0x10	0x05	count_devices
0x10	0x06	create_device_list
0x10	0x07	delete_device_list
0x10	0x08	next_device_in_list
0x10	0x09	rewind_device_list
0x10	0x0a	run_filter
0x10	0x10	set_device_register
0x10	0x11	get_device_register
0x10	0x12	send_to_device
0x10	0x13	receive_from_device

All of these functions have to be implemented for the driver to be recognized as PCI driver and to make it a viable option as the default PCI driver for the bootup process.

0x00: init_driver

Initializes the driver. Only used in the internal procedures of the PCI interaction code.

Inputs:

0. (Empty) Driver Slot Pointer

0x02: reset_driver

Sets back the driver to the initial state. This will be called when the driver misbehaves in a way that indicates a bug.

Inputs:

0. (PCI) Driver Slot Pointer

0x03: cleanup_driver

As counterpart to init_driver, this function frees the resources of the PCI driver it's called on. The driver shouldn't work after this has been called because all of the items it needs for working should have been deleted.

Inputs:

0. (PCI) Driver Slot Pointer

0x05: count_devices

Retrieves the number of devices that the PCI driver found during the enumeration in the initialization phase.

Inputs:

0. (PCI) Driver Slot Pointer

Result:

• EAX: Number of devices in the host computer.

0x06: create_device_list

Creates an opaque structure that contains a filter-able list of devices and is represented by a 4-byte identifier. When using the driver, the 4-byte identifier should be the only thing that is needed for handling device lists.

Inputs:

0. (PCI) Driver Slot Pointer

Result:

• EAX: Device List Identifier

0x07: delete_device_list

Deletes the driver-internal structure(s) related to the device list. The devices should be stored seperately so that they can be accessed and used even if the list they were gotten from has been deleted.

0. (PCI) Driver Slot Pointer
1. Device List Identifier

0x08: next_device_in_list

Goes one device further in the device list and returns another integer identifying the device's (not the device list's) opaque structure.

Inputs:

0. (PCI) Driver Slot Pointer
1. Device List Identifier

Result:

• EAX: Next device's identifier

0x09: rewind_device_list

Goes back some amount of devices in the device list.

Inputs:

0. (PCI) Driver Slot Pointer
1. Device List Identifier
2. Amount of devices to rewind
   If the amount of devices to rewind is bigger or equal to the amount of devices, the driver should rewind the list back to the start.

0x0a: run_filter

Runs a filter function that returns either TRUE or FALSE depending on whether the device should stay in the list the filter was run on or if the device should be thrown out the list.

Inputs:

0. (PCI) Driver Slot Pointer
1. Device List Identifier
2. Filter-Function Pointer

Result:

• EAX: Number of remaining devices in the list

Filter Function

Every function for which a pointer is given to this function has the following inputs from 0 (nearest to EBP) to 3 (furthest from EBP):

0. (PCI) Driver Slot Pointer
1. Device List Identifier
2. Device List index
3. Device Identifier

The call to the function could thus be written in Assembly like in the following code block:

push ebp
mov ebp, esp
push ebx
push ecx
push edi
push edx
call eax
mov esp, ebp
pop ebp

Assuming that when entering that snippet, the registers contain the following information:

• EAX: function pointer
• EBX: driver slot
• ECX: device list identifier
• EDX: device identifier
• EDI: device list index