#include "kernel/kernel.h"
#include "log.h"
#include "asm_x86.h"
#include "e1000.h"

#define PCI_CONFIG_DATA	    0xCFC
#define PCI_CONFIG_ADDRESS  0xCF8

static uint32_t e1000_addr;

static char *get_class(uint8_t v)
{
    switch(v)
    {
	case 0x00: return "Unclassified";
    }
    return "Unknown";
}

 void pciConfigSet (uint8_t bus, uint8_t slot,
                             uint8_t func, uint8_t offset, uint32_t data)
 {
    uint32_t address;
    uint32_t lbus  = (uint32_t)bus;
    uint32_t lslot = (uint32_t)slot;
    uint32_t lfunc = (uint32_t)func;
    uint16_t tmp = 0;
 
    /* create configuration address as per Figure 1 */
    address = (uint32_t)((lbus << 16) | (lslot << 11) |
              (lfunc << 8) | (offset & 0xfc) | ((uint32_t)0x80000000));
 
    /* write out the address */
    x86_outl (0xCF8, address);
    x86_outl (0xCFC,data);

 }
 uint16_t pciConfigReadWord (uint8_t bus, uint8_t slot,
                             uint8_t func, uint8_t offset)
 {
    uint32_t address;
    uint32_t lbus  = (uint32_t)bus;
    uint32_t lslot = (uint32_t)slot;
    uint32_t lfunc = (uint32_t)func;
    uint16_t tmp = 0;
 
    /* create configuration address as per Figure 1 */
    address = (uint32_t)((lbus << 16) | (lslot << 11) |
              (lfunc << 8) | (offset & 0xfc) | ((uint32_t)0x80000000));
 
    /* write out the address */
    x86_outl (0xCF8, address);
    /* read in the data */
    /* (offset & 2) * 8) = 0 will choose the first word of the 32 bits register */
    tmp = (uint16_t)((x86_inl (0xCFC) >> ((offset & 2) * 8)) & 0xffff);
    return (tmp);
 }

uint32_t test_bar(uint8_t bus, uint8_t slot, uint8_t offset)
{

    uint16_t bar_low=pciConfigReadWord(bus,slot,0,offset);
    uint16_t bar_high=pciConfigReadWord(bus,slot,0,offset+2);
    
    // check size
    pciConfigSet(bus,slot,0,offset,0xffffffff);
    uint16_t size_low=pciConfigReadWord(bus,slot,0,offset);
    uint16_t size_high=pciConfigReadWord(bus,slot,0,offset+2);
    uint32_t size=(size_high<<16)+size_low;
    size=~size;
    size++;
    //

    // restore original values
    pciConfigSet(bus,slot,0,offset,(bar_high<<16)+bar_low);
     
    klog("%s bar: (0x%x 0x%x) size: 0x%x" ,bar_low&1?"i/o":"mem",bar_high, bar_low, size);
    if((bar_low&1)==0) // mem space
    {
	klog("type=0x%x,base_addr=0x%08X",0b110&bar_low,(bar_low+(bar_high<<16))&0xFFFFFFF0);
    }

    return (bar_low+(bar_high<<16))&0xFFFFFFF0;
}

uint16_t pciCheck(uint8_t bus, uint8_t slot)
{

    //https://pci-ids.ucw.cz/v2.2/pci.ids
    uint16_t vendor, device, irq;

    /* try and read the first configuration register. Since there are no */
    /* vendors that == 0xFFFF, it must be a non-existent device. */
    if ((vendor = pciConfigReadWord(bus,slot,0,0)) != 0xFFFF) 
    {
	    device = pciConfigReadWord(bus,slot,0,2);

	    //pciConfigSet(bus,slot,0,0x3c+2,0x3);
	    irq = pciConfigReadWord(bus,slot,0,0x3c);
	    uint8_t header = pciConfigReadWord(bus,slot,0,0xd)&0xff;

	    klog("[%d,%d]: vendor: 0x%x / device: 0x%x",bus,slot,vendor,device);

	    klog("header_typ=%x, %d,pin=%d , irq=%d",header,irq,irq&0xFf00,irq&0xFf);

	    // check for: E1000 (82540EM). PCI Ethernet Controller
	    if(vendor==0x8086&&device==0x100e)
	    {
		uint16_t command = pciConfigReadWord(bus,slot,0,0x04);
		pciConfigSet(bus,slot,0,0x04,command|1<<2);
		command = pciConfigReadWord(bus,slot,0,0x04);

		klog("enable busmastering / command register: %04X",command);
	//	uint16_t irq=pciConfigReadWord(bus,slot,0,0x3C);
	//	uint16_t irq2=pciConfigReadWord(bus,slot,0,0x3E);
	//

		e1000_addr=test_bar(bus,slot,0x10);
		test_bar(bus,slot,0x14);
	//	scr_put_hex(irq);
	//	scr_put_hex(irq2);
	 //       scr_put_string_nl(";");


	    }



	    
    } 
    
    return (vendor);

}

uint32_t pci_init()
{
    klog("scanning bus");
    // todo: recurse on pci to pci bridges! 
    // todo: support multiple pci host controllers! 
    // (check more funcitons of device 0:0)

    uint16_t bus;
    uint8_t device;
	  
	for(bus = 0; bus < 256; bus++)
	{
           for(device = 0; device < 32; device++) 
	   {
	       pciCheck(bus, device);
	    }

	}
    return e1000_addr;

}