---
title: pci.h
summary: PCI bus stuff
---

# Class and subclasses enums
All these enums are not documented in here, because they are basically just the definitions matching the PCI device main and sub classes.
A [list of these (sub)classes](https://wiki.osdev.org/PCI#Class_Codes) can be found in the osdev wiki.

# `pci_device_header_T` - struct
| Name            | Type     | Description                                                                                                                  |
|-----------------|----------|------------------------------------------------------------------------------------------------------------------------------|
| vendor_id       | uint16_t | The Device manufacturers ID number                                                                                           |
| device_id       | uint16_t | The devices ID number                                                                                                        |
| command_reg     | uint16_t | Provides control over a device's ability to generate and respond to PCI cycles.                                              |
| status          | uint16_t | The status register PCI bus related events                                                                                   |
| revision_id     | uint8_t  | The devices revision ID number                                                                                               |
| progif          | uint8_t  | Programming Interface Byte. This can specify special programming interfaces.                                                 |
| subclass        | uint8_t  | The special function that the device performs.                                                                               |
| main_class      | uint8_t  | The general function class, which the device operates in.                                                                    |
| cache_line_size | uint8_t  | Specifies the system cache line size in 32-bit units.                                                                        |
| latency_timer   | uint8_t  | Specifies the latency timer in units of PCI bus clocks.                                                                      |
| header_type     | uint8_t  | Specifies whether the device is a general device or a bridge. This affects the data representation that follows this header. |
| bist            | uint8_t  | Built-In-Self-Test status and control.                                                                                       |

# `pci_header_0_T` - struct
| Name                       | Type                | Description                                                                                     |
|----------------------------|---------------------|-------------------------------------------------------------------------------------------------|
| header                     | pci_device_header_T | The devices base header                                                                         |
| bar0                       | uint32_t            | Base address 0                                                                                  |
| bar1                       | uint32_t            | Base address 1                                                                                  |
| bar2                       | uint32_t            | Base address 2                                                                                  |
| bar3                       | uint32_t            | Base address 3                                                                                  |
| bar4                       | uint32_t            | Base address 4                                                                                  |
| bar5                       | uint32_t            | Base address 5                                                                                  |
| cardbus_cis_pointer        | uint32_t            | Used by devices that share silicon between CardBus and PCI.                                     |
| subsystem_vendor_id        | uint16_t            | idk, but probably not that important                                                            |
| subsystem_id               | uint16_t            | idk, but probably not that important                                                            |
| expansion_rom_base_address | uint32_t            | An optional max 16MB ROM BAR.                                                                   |
| capabilities               | uint8_t             | An offset in the devices config space that points to a linked list of implemented capabilities. |
| reserved                   | uint8_t[7]          | Reserved.                                                                                       |
| interrupt_line             | uint8_t             | The devices interrupt IRQ.                                                                      |
| interrupt_pin              | uint8_t             | The devices interrupt pin.                                                                      |
| min_grant                  | uint8_t             | Specifies the burst period length, in 1/4 microsecond units, that the device needs.             |
| max_latency                | uint8_t             | Specifies how often the device needs access to the PCI bus (in 1/4 microsecond units).          |

# `pci_device_T` - struct
| Name   | Type                 | Description             |
|--------|----------------------|-------------------------|
| header | pci_device_header_T* | The devices base header |
| prev   | pci_device_T*        | The previous device.    |
| next   | pci_device_T*        | The next device.        |

# `pci_manager_T` - struct
| Name    | Type          | Description                                   |
|---------|---------------|-----------------------------------------------|
| devices | pci_device_T* | The linked list of devices connected via PCI. |

# `pci_init()` - function (void)
Initializes the global PCI manager and enumerates the PCI bus.
This needs to be called after `acpi_init`, because it uses the _MCFG_ table.

# `pci_manager_add_device(header*)` - function (void)
Adds a device to the global PCI manager.
This should only be called by the PCI enumerator.

# `pci_manager_remove_device(device*)` - function (void)
Removes a device from the global PCI manager, and frees it resources in the manager.

# `pci_manager_find_device(class, subclass, progif)` - function (pci_device_T*)
Returns the first device with **_class_**, **_subclass_** and **_progif_** that is defined in the global PCI manager.

# `pci_manager_dump_devices()` - function (void)
Logs a list of all registered PCI devices.

# `pci_get_subclass_string(class, subclass)` - function (string_t)
Returns the Name of **_class_** + **_subclass_**.

# `pci_get_vendor_string(vendor_id)` - function (string_t)
Returns the name of the vendor.