/*
	mini - a Free Software replacement for the Nintendo/BroadOn IOS.
	PowerPC ELF file loading

Copyright (C) 2008, 2009	Hector Martin "marcan" <marcan@marcansoft.com>
Copyright (C) 2009			Andre Heider "dhewg" <dhewg@wiibrew.org>

# This code is licensed to you under the terms of the GNU GPL, version 2;
# see file COPYING or http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
*/

#include "types.h"
#include "powerpc.h"
#include "hollywood.h"
#include "utils.h"
#include "start.h"
#include "gecko.h"
#include "ff.h"
#include "powerpc_elf.h"
#include "elf.h"
#include "memory.h"
#include "string.h"

extern u8 __mem2_area_start[];

#define PPC_MEM1_END	(0x017fffff)
#define PPC_MEM2_START	(0x10000000)
#define PPC_MEM2_END	((u32) __mem2_area_start)

#define PHDR_MAX 10

static int _check_physaddr(u32 addr) {
	if ((addr >= PPC_MEM2_START) && (addr <= PPC_MEM2_END))
		return 2;

	if (addr < PPC_MEM1_END)
		return 1;

	return -1;
}

static int _check_physrange(u32 addr, u32 len) {
	switch (_check_physaddr(addr)) {
	case 1:
		if ((addr + len) < PPC_MEM1_END)
			return 1;
		break;
	case 2:
		if ((addr + len) < PPC_MEM2_END)
			return 2;
		break;
	}

	return -1;
}

static Elf32_Ehdr elfhdr;
static Elf32_Phdr phdrs[PHDR_MAX];

int powerpc_boot_file(const char *path)
{
	u32 read;
	FIL fd;
	FRESULT fres;

	fres = f_open(&fd, path, FA_READ);
	if (fres != FR_OK)
		return -fres;

	fres = f_read(&fd, &elfhdr, sizeof(elfhdr), &read);
	
	if (fres != FR_OK)
		return -fres;

	if (read != sizeof(elfhdr))
		return -100;

	if (memcmp("\x7F" "ELF\x01\x02\x01\x00\x00",elfhdr.e_ident,9)) {
		gecko_printf("Invalid ELF header! 0x%02x 0x%02x 0x%02x 0x%02x\n",elfhdr.e_ident[0], elfhdr.e_ident[1], elfhdr.e_ident[2], elfhdr.e_ident[3]);
		return -101;
	}

	if (_check_physaddr(elfhdr.e_entry) < 0) {
		gecko_printf("Invalid entry point! 0x%08x\n", elfhdr.e_entry);
		return -102;
	}

	if (elfhdr.e_phoff == 0 || elfhdr.e_phnum == 0) {
		gecko_printf("ELF has no program headers!\n");
		return -103;
	}

	if (elfhdr.e_phnum > PHDR_MAX) {
		gecko_printf("ELF has too many (%d) program headers!\n", elfhdr.e_phnum);
		return -104;
	}

	fres = f_lseek(&fd, elfhdr.e_phoff);
	if (fres != FR_OK)
		return -fres;

	fres = f_read(&fd, phdrs, sizeof(phdrs[0])*elfhdr.e_phnum, &read);
	if (fres != FR_OK)
		return -fres;

	if (read != sizeof(phdrs[0])*elfhdr.e_phnum)
		return -105;

	u16 count = elfhdr.e_phnum;
	Elf32_Phdr *phdr = phdrs;

	powerpc_hang();

	while (count--) {
		if (phdr->p_type != PT_LOAD) {
			gecko_printf("Skipping PHDR of type %d\n", phdr->p_type);
		} else {
			if (_check_physrange(phdr->p_paddr, phdr->p_memsz) < 0) {
				gecko_printf("PHDR out of bounds [0x%08x...0x%08x]\n",
								phdr->p_paddr, phdr->p_paddr + phdr->p_memsz);
				return -106;
			}

			void *dst = (void *) phdr->p_paddr;

			gecko_printf("LOAD 0x%x @0x%08x [0x%x]\n", phdr->p_offset, phdr->p_paddr, phdr->p_filesz);
			fres = f_lseek(&fd, phdr->p_offset);
			if (fres != FR_OK)
				return -fres;
			fres = f_read(&fd, dst, phdr->p_filesz, &read);
			if (fres != FR_OK)
				return -fres;
			if (read != phdr->p_filesz)
				return -107;
		}
		phdr++;
	}

	dc_flushall();

	gecko_printf("ELF load done, booting PPC...\n");
	powerpc_upload_stub(elfhdr.e_entry);
	powerpc_reset();
	gecko_printf("PPC booted!\n");

	return 0;
}

int powerpc_boot_mem(const u8 *addr, u32 len)
{
	if (len < sizeof(Elf32_Ehdr))
		return -100;

	Elf32_Ehdr *ehdr = (Elf32_Ehdr *) addr;

	if (memcmp("\x7F" "ELF\x01\x02\x01\x00\x00", ehdr->e_ident, 9)) {
		gecko_printf("Invalid ELF header! 0x%02x 0x%02x 0x%02x 0x%02x\n",
						ehdr->e_ident[0], ehdr->e_ident[1],
						ehdr->e_ident[2], ehdr->e_ident[3]);
		return -101;
	}

	if (_check_physaddr(ehdr->e_entry) < 0) {
		gecko_printf("Invalid entry point! 0x%08x\n", ehdr->e_entry);
		return -102;
	}

	if (ehdr->e_phoff == 0 || ehdr->e_phnum == 0) {
		gecko_printf("ELF has no program headers!\n");
		return -103;
	}

	if (ehdr->e_phnum > PHDR_MAX) {
		gecko_printf("ELF has too many (%d) program headers!\n",
						ehdr->e_phnum);
		return -104;
	}

	u16 count = ehdr->e_phnum;
	if (len < ehdr->e_phoff + count * sizeof(Elf32_Phdr))
		return -105;

	Elf32_Phdr *phdr = (Elf32_Phdr *) &addr[ehdr->e_phoff];

	// TODO: add more checks here
	// - loaded ELF overwrites itself?

	powerpc_hang();

	while (count--) {
		if (phdr->p_type != PT_LOAD) {
			gecko_printf("Skipping PHDR of type %d\n", phdr->p_type);
		} else {
			if (_check_physrange(phdr->p_paddr, phdr->p_memsz) < 0) {
				gecko_printf("PHDR out of bounds [0x%08x...0x%08x]\n",
								phdr->p_paddr, phdr->p_paddr + phdr->p_memsz);
				return -106;
			}

			gecko_printf("LOAD 0x%x @0x%08x [0x%x]\n", phdr->p_offset, phdr->p_paddr, phdr->p_filesz);
			memcpy((void *) phdr->p_paddr, &addr[phdr->p_offset],
					phdr->p_filesz);
		}
		phdr++;
	}

	dc_flushall();

	gecko_printf("ELF load done, booting PPC...\n");
	powerpc_upload_stub(ehdr->e_entry);
	powerpc_reset();
	gecko_printf("PPC booted!\n");

	return 0;
}