#include <pci.h>
#include <lib.h>
#include <panic.h>

#define PCI_INTERNAL
#include <sys/pci.h>

#define TABLE_LEN 16

struct pci_table_entry {
	struct pci_device device;
	uint16_t device_id;
	uint16_t vendor_id;
	uint8_t class;
	uint8_t subclass;
	uint8_t prog_if;
	uint8_t revision;
};

uint32_t pci_rcfg_d(struct pci_device dev, uint8_t offset) {
	return pci_sys_rcfg_d(dev, offset);
}

uint16_t pci_rcfg_w(struct pci_device dev, uint8_t offset) {
	return pci_sys_rcfg_w(dev, offset);
}

uint8_t  pci_rcfg_b(struct pci_device dev, uint8_t offset) {
	return pci_sys_rcfg_b(dev, offset);
}

void pci_wcfg_d(struct pci_device dev, uint8_t offset, uint32_t dword) {
	pci_sys_wcfg_d(dev, offset, dword);
}

void pci_wcfg_w(struct pci_device dev, uint8_t offset, uint16_t word) {
	pci_sys_wcfg_w(dev, offset, word);
}

void pci_wcfg_b(struct pci_device dev, uint8_t offset, uint8_t byte) {
	pci_sys_wcfg_b(dev, offset, byte);
}

static struct pci_table_entry pci_table[TABLE_LEN];
static size_t pci_table_next = 0;


static void print_device(struct pci_table_entry *entry) {
	kprintf(
		"BUS: %#-4x  DEV: %#-4x  FUNC: %#-4x  ID: %04x:%04x  CLASS: %02x:%02x:%02x  REV: %#02x\n",
		entry->device.bus,
		entry->device.device,
		entry->device.function,
		entry->vendor_id,
		entry->device_id,
		entry->class,
		entry->subclass,
		entry->prog_if,
		entry->revision
	);
}

static struct pci_table_entry *load_device(struct pci_device dev) {
	if (pci_table_next >= TABLE_LEN) panic("Too many PCI devices: limit is %d", TABLE_LEN);
	struct pci_table_entry *entry = &pci_table[pci_table_next++];
	entry->device = dev;
	uint32_t dword0 = pci_rcfg_d(dev, 0);
	uint32_t dword2 = pci_rcfg_d(dev, 8);

	entry->device_id = (dword0 >> 16) & 0xFFFF;
	entry->vendor_id = dword0 & 0xFFFF;

	entry->class = (dword2 >> 24) & 0xFF;
	entry->subclass = (dword2 >> 16) & 0xFF;
	entry->prog_if = (dword2 >> 8) & 0xFF;
	entry->revision = dword2 & 0xFF;

	return entry;
}

void pci_init(void) {
	pci_table_next = 0;
	struct pci_device pcidev;
	for (int bus = 0; bus < 256; bus++) {
		pcidev.bus = bus;
		for (int dev = 0; dev < 32; dev++) {
			pcidev.device = dev;
			pcidev.function = 0;

			uint16_t vendor = pci_rcfg_w(pcidev, 0);
			if (vendor == 0xFFFF) continue;

			load_device(pcidev);

			uint8_t header_type = pci_rcfg_b(pcidev, 14);

			if (!(header_type & 0x80)) continue;
			for (int func = 1; func < 8; func++) {
				pcidev.function = func;

				uint16_t vendor = pci_rcfg_w(pcidev, 0);
				if (vendor == 0xFFFF) continue;

				load_device(pcidev);
			}
		}
	}
	kprintf("PCI DEVICES\n");
	for (size_t i = 0; i < pci_table_next; i++) {
		print_device(&pci_table[i]);
	}
	kprintf("\n");
}

bool pci_findby_class(struct pci_device *dest, uint8_t class, uint8_t subclass, size_t *offset) {
	size_t o = 0;
	if (offset == NULL) offset = &o;
	for (; *offset < pci_table_next; (*offset)++) {
		struct pci_table_entry *entry = &pci_table[*offset];
		if (entry->class == class && entry->subclass == subclass) {
			*dest = entry->device;
			return true;
		}
	}
	return false;
}

bool pci_findby_id(struct pci_device *dest, uint16_t device, uint16_t vendor, size_t *offset) {
	size_t o = 0;
	if (offset == NULL) offset = &o;
	for (; *offset < pci_table_next; (*offset)++) {
		struct pci_table_entry *entry = &pci_table[*offset];
		if (entry->device_id == device && entry->vendor_id == vendor) {
			*dest = entry->device;
			return true;
		}
	}
	return false;
}