/** Linux PCI helpers
 *
 * @file
 * @author Steffen Vogel <post@steffenvogel.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license Apache License 2.0
 *********************************************************************************/

#pragma once

#include <list>
#include <fstream>

#include <cstddef>
#include <cstdint>

#include <villas/log.hpp>

namespace villas {
namespace kernel {
namespace pci {

#define PCI_SLOT(devfn)		(((devfn) >> 3) & 0x1f)
#define PCI_FUNC(devfn)		((devfn) & 0x07)

class Id {
public:
	Id(const std::string &str);

	Id(int vid = 0, int did = 0, int cc = 0) :
		vendor(vid),
		device(did),
		class_code(cc)
	{ }

	bool operator==(const Id &i);

	unsigned int vendor;
	unsigned int device;
	unsigned int class_code;
};

class Slot {
public:
	Slot(const std::string &str);

	Slot(int dom = 0, int b = 0, int dev = 0, int fcn = 0) :
		domain(dom),
		bus(b),
		device(dev),
		function(fcn)
	{ }

	bool operator==(const Slot &s);

	unsigned int domain;
	unsigned int bus;
	unsigned int device;
	unsigned int function;
};

struct Region {
	int num;
	uintptr_t start;
	uintptr_t end;
	unsigned long long flags;
};

class Device {
public:
	Device(Id i, Slot s) :
		id(i),
		slot(s),
		log(logging.get("kernel:pci"))
	{ }

	Device(Id i) :
		id(i),
		log(logging.get("kernel:pci"))
	{ }

	Device(Slot s) :
		slot(s),
		log(logging.get("kernel:pci"))
	{ }

	bool
	operator==(const Device &other);

	// Get currently loaded driver for device.
	std::string getDriver() const;

	// Bind a new LKM to the PCI device.
	bool attachDriver(const std::string &driver) const;

	// Return the IOMMU group of this PCI device or -1 if the device is not in a group.
	int getIommuGroup() const;

	std::list<Region> getRegions() const;

	// Write 32-bit BAR value from to the PCI configuration space
	void writeBar(uint32_t addr, unsigned bar = 0);

	// If BAR values in config space and in the kernel do not match, rewrite
	// the BAR value of the kernel to PCIe config space.
	void rewriteBar(unsigned bar = 0);

	// Read 32-bit BAR value from the PCI configuration space.
	uint32_t readBar(unsigned bar = 0) const;

	// Read 32-bit BAR value from the devices resource file. This is what the kernel
	// thinks the BAR should be.
	uint32_t readHostBar(unsigned bar = 0) const;

	Id id;
	Slot slot;
private:
	villas::Logger log;

protected:
	std::fstream openSysFs(const std::string subPath, std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) const;
};

class DeviceList : public std::list<std::shared_ptr<Device>> {
public:
	// Initialize Linux PCI handle.
	//
	// This search for all available PCI devices under /sys/bus/pci
	DeviceList();

	DeviceList::value_type lookupDevice(const Slot &s);

	DeviceList::value_type lookupDevice(const Id &i);

	DeviceList::value_type lookupDevice(const Device &f);
};

} // namespace pci
} // namespace kernel
} // namespace villas