jsix/src/kernel/pci.h

#pragma once
/// \file pci.h
/// PCI devices and groups

#include <stdint.h>
#include <util/pointers.h>

struct pci_group;
enum class isr : uint8_t;

struct pci_cap
{
    enum class type : uint8_t
    {
        msi     = 0x05,
        msix    = 0x11
    };

    type id;
    uint8_t next;
} __attribute__ ((packed));


/// Information about a discovered PCIe device
class pci_device
{
public:
    /// Default constructor creates an empty object.
    pci_device();

    /// Constructor
    /// \arg group  The group of this device's bus
    /// \arg bus    The bus number this device is on
    /// \arg device The device number of this device
    /// \arg func   The function number of this device
    pci_device(pci_group &group, uint8_t bus, uint8_t device, uint8_t func);

    /// Check if this device is multi-function.
    /// \returns  True if this device is multi-function
    inline bool multi() const { return m_multi; }

    /// Get the bus number this device is on.
    /// \returns  The bus number
    inline uint8_t bus() const { return (m_bus_addr >> 8); }

    /// Get the device number of this device on its bus
    /// \returns  The device number
    inline uint8_t device() const { return (m_bus_addr >> 3) & 0x1f; }

    /// Get the function number of this device on its device
    /// \returns  The function number
    inline uint8_t function() const { return m_bus_addr & 0x7; }

    /// Get the device class
    /// \returns  The PCI device class
    inline uint8_t devclass() const { return m_class; }

    /// Get the device subclass
    /// \returns  The PCI device subclass
    inline uint8_t subclass() const { return m_subclass; }

    /// Get the device program interface
    /// \returns  The PCI device program interface
    inline uint8_t progif() const { return m_progif; }

    /// Read one of the device's Base Address Registers
    /// \arg i   Which BAR to read (up to 5 for non-bridges)
    /// \returns The contents of the BAR
    uint32_t get_bar(unsigned i);

    /// Write one of the device's Base Address Registers
    /// \arg i   Which BAR to read (up to 5 for non-bridges)
    /// \arg val The value to write
    void set_bar(unsigned i, uint32_t val);

    /// Write to the MSI registers
    /// \arg addr  The address to write to the MSI address registers
    /// \arg data  The value to write to the MSI data register
    void write_msi_regs(uintptr_t addr, uint16_t data);

    /// Get a bus address, given the bus/device/function numbers.
    /// \arg bus    Number of the bus
    /// \arg device Index of the device on the bus
    /// \arg func   The function number within the device
    /// \returns    The computed bus_addr
    static inline uint16_t bus_addr(uint8_t bus, uint8_t device, uint8_t func)
    {
        return bus << 8 | device << 3 | func;
    }

private:
    uint32_t *m_base;
    pci_cap *m_msi;

    /// Bus address: 15:8 bus, 7:3 device, 2:0 device
    uint16_t m_bus_addr;

    uint16_t m_vendor;
    uint16_t m_device;

    uint8_t m_class;
    uint8_t m_subclass;
    uint8_t m_progif;
    uint8_t m_revision;
    bool m_multi;

    // Might as well cache these to fill out the struct align
    isr m_irq;
    uint8_t m_header_type;
};


/// Represents data about a PCI bus group from the ACPI MCFG
struct pci_group
{
    uint16_t group;
    uint16_t bus_start;
    uint16_t bus_end;

    uint32_t *base;

    /// Get the base address of the MMIO configuration registers for a device
    /// \arg bus    The bus number of the device (relative to this group)
    /// \arg device The device number on the given bus
    /// \arg func   The function number on the device
    /// \returns    A pointer to the memory-mapped configuration registers
    inline uint32_t * base_for(uint8_t bus, uint8_t device, uint8_t func)
    {
        return util::offset_pointer(base,
                pci_device::bus_addr(bus, device, func) << 12);
    }

    /// Check if the given device function is present.
    /// \arg bus    The bus number of the device (relative to this group)
    /// \arg device The device number on the given bus
    /// \arg func   The function number on the device
    /// \returns    True if the device function is present
    bool has_device(uint8_t bus, uint8_t device, uint8_t func);
};