// Advanced Configuration and Power Interface
// http://wiki.xomb.org/index.php?title=ACPI_Tables

#define FOOLOS_MODULE_NAME "acpi"

#include "lib/logger/log.h"
#include "lib/int/stdint.h"
#include "lib/bool/bool.h"
#include "lib/string/string.h"
#include "smp.h"


typedef struct acpi_rsdt_struct
{
    char sig[4];
    uint32_t length;
    uint8_t revision;
    uint8_t checksum;
    char oemid[6];
    char oemtabid[8];
    uint32_t oemrevision;
    uint32_t vendor;
    uint32_t rev;
}acpi_rsdt;

typedef struct aspi_rsdp_struct
{
    char sig[8]; //signature
    uint8_t checksum;
    char oem[6];
    uint8_t revision;

    uint32_t ptr_rsdt;
    uint32_t length;

    uint64_t ptr_xsdt; //same info but with 64bit pointers (preferred)
    uint8_t checksum_ext;
    uint8_t reserved[3];

}acpi_rsdp;

typedef struct 
{
    char sig[4];
    uint32_t length;
    uint8_t rev;
    uint8_t checksum;
    char oemid[6];
    char oemtableid[8];
    char oemrev[4];
    char creatorid[4];
    char creatorrev[4];
    uint32_t apic_local;
    uint32_t flags;

}acpi_madt;

uint8_t *apci_get_next_entry(uint8_t *addr,smp_processors *procdata)
{

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_DEBUG,"Examining MADT Entry at 0x%08X",addr);

    if(*addr==0)
    {
	log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"MADT Entry: LocalAPIC");
	// usable
	if(addr[4]&1)
	{
	    if(procdata->processors>=SMP_MAX_PROC){

		panic(FOOLOS_MODULE_NAME,"we do not support that many processors. recompile with higher SMP_MAX_PROC.");
	    }

	    procdata->local_apic_id[procdata->processors]=addr[3];
	    procdata->processors++;
	}

    }
    else if(*addr==1)
    {
	log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"MADT Entry: IO APIC");
    }
    else if(*addr==2)log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"MADT Entry: Interrupt Source Override");
    else log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"MADT Entry: type:0x%X",*addr);

    return addr+addr[1];
}


void acpi_check_madt(uint32_t *madt,smp_processors *procdata)
{
    acpi_madt *table=(acpi_madt *)*madt;

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_DEBUG,"Looking for MADT Table at %08X.",table);
    if(strcmp("APIC",table->sig,4))
    {
	log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Found MADT Table at 0x%08X",table);
	uint8_t *end=(uint8_t *)table;
	end+=table->length;

	uint8_t *entry=(uint8_t *)table;
	entry+=sizeof(acpi_madt);

	procdata->local_apic_address=table->apic_local;

	while(entry<end)
	{
	    entry=apci_get_next_entry(entry,procdata);
	}

	
    }
}

void acpi_read_rsdt(acpi_rsdt *rsdt,smp_processors *procdata)
{
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Reading RSDT Table at 0x%08X",rsdt);

    if(!strcmp("RSDT",rsdt->sig,4)) 
	panic(FOOLOS_MODULE_NAME,"Signature MISMATCH!");

    int entries=(rsdt->length-sizeof(acpi_rsdt))/4;
    uint32_t *first=(uint32_t *)rsdt;
    first+=sizeof(acpi_rsdt)/4;

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Entries: %d",entries);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Looking for MADT Table");
    for(int i=0;i<entries;i++)
    {

	acpi_check_madt(first,procdata);
	first++;
    }

}

// search for the RSDB table in
// 0x7ffff - 0x9ffff (max)
// 0xe0000 - 0xfffff

bool acpi_find(smp_processors *procdata)
{
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Looking for RSDP Table");
    char *search=(char *)0x9f000; //will be 16 bit aligned;
    procdata->processors=0;
    procdata->boot=0;

    while(search<=(char *)0xfffff)
    {
	if(strcmp("RSD PTR ",search,8)) // notice trailing space in "RSD PTR "
	{
		uint8_t checksum=0;
		for(int i=0;i<20;i++)
		    checksum+=search[i];

		if(checksum==0)
		{
		    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"RSDP Table found at 0x%08X",search);
		    acpi_rsdp *rsdp=(acpi_rsdp *)search;
		    acpi_read_rsdt(rsdp->ptr_rsdt,procdata);
		    return true;
		}
	}

	search++;
	
	if(search==0xa0000)search=0xe0000;
		
    }
    return false;
}