#include "pci.h"

#include "string.h"
#include "stdio.h"

#define NOF_BUSES 8
#define NOF_DEVICES_PER_BUS 32
#define NOF_FUNCTIONS_PER_DEVICE 8

void pci_controller_init( pci_controller_t *controller )
{
	memset( controller, 0, sizeof( pci_controller_t ) );

	port32_init( &controller->command_port, 0xCF8 );
	port32_init( &controller->data_port, 0xCFC );
}

static uint32_t compute_id( uint16_t bus, uint16_t device, uint16_t function, uint32_t offset )
{
	uint32_t id;

	id = ( 0x01 << 31 )
		| ( ( bus & 0xFF ) << 16 )
		| ( ( device & 0x1F ) << 11 )
		| ( ( function & 0x07 ) << 8 )
		| ( offset & 0xFC );

	return id;
}

uint16_t pci_controller_read( pci_controller_t *controller, uint16_t bus, uint16_t device, uint16_t function, uint32_t offset )
{
	uint32_t id = compute_id( bus, device, function, offset );

	port32_write( &controller->command_port, id );

	uint32_t data = port32_read( &controller->data_port );

	// we get 256 byte data blocks aligned to 32-bit addresses
	// for each offset
	data = data >> ( ( 8 * ( offset % 4 ) ) & 0xFFFF );

	return data;
}

void pci_controller_write( pci_controller_t *controller, uint16_t bus, uint16_t device, uint16_t function, uint32_t offset, uint32_t data )
{
	uint32_t id = compute_id( bus, device, function, offset );

	port32_write( &controller->command_port, id );
	port32_write( &controller->data_port, data );
}

void pci_controller_scan_and_register( pci_controller_t *controller, driver_manager_t *driver_manager, interrupt_t *interrupt )
{
	for( int bus = 0; bus < NOF_BUSES; bus++ ) {
		for( int device = 0; device < NOF_DEVICES_PER_BUS; device++ ) {
			// TODO: detect single/multi function device from header
			for( int function = 0; function < NOF_FUNCTIONS_PER_DEVICE; function++ ) {
				pci_device_descriptor_t device_descriptor;
				pci_device_descriptor_init( &device_descriptor, controller, bus, device, function );

				// no device
				if( device_descriptor.device_id == 0x0 ||
					device_descriptor.device_id == 0xFFFF ) {
					continue;
				}

				printf( "%X:%X.%d: %X:%X (interface: %X, class %X:%X, rev: %d)\n",
					bus, device, function,
					device_descriptor.vendor_id,
					device_descriptor.device_id,
					device_descriptor.interface_id,
					device_descriptor.class_id,
					device_descriptor.subclass_id,
					device_descriptor.revision_id );
			}
		}
	}
}

void pci_device_descriptor_init( pci_device_descriptor_t *descriptor, pci_controller_t *controller, uint16_t bus, uint16_t device, uint16_t function )
{
	memset( descriptor, 0, sizeof( pci_device_descriptor_t ) );

	descriptor->vendor_id = pci_controller_read( controller, bus, device, function, 0x00 );
	descriptor->device_id = pci_controller_read( controller, bus, device, function, 0x02 );
	descriptor->class_id = pci_controller_read( controller, bus, device, function, 0x0B );
	descriptor->subclass_id = pci_controller_read( controller, bus, device, function, 0x0A );
	descriptor->interface_id = pci_controller_read( controller, bus, device, function, 0x09 );
	descriptor->revision_id = pci_controller_read( controller, bus, device, function, 0x08 );
}

void pci_base_address_register_init( pci_base_address_register_t *base_address_register, pci_controller_t *controller, uint16_t bus, uint16_t device, uint16_t function, uint16_t bar )
{
	memset( base_address_register, 0, sizeof( pci_base_address_register_t ) );
}