//-----------------------------------------------------------------------------
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Main code for the bootloader
//-----------------------------------------------------------------------------

#include <proxmark3.h>
#include "usb_cdc.h"
#include "cmd.h"
//#include "usb_hid.h"

void DbpString(char *str) {
  byte_t len = 0;
  while (str[len] != 0x00) {
    len++;
  }
  cmd_send(CMD_DEBUG_PRINT_STRING,len,0,0,(byte_t*)str,len);
}

struct common_area common_area __attribute__((section(".commonarea")));
unsigned int start_addr, end_addr, bootrom_unlocked;
extern char _bootrom_start, _bootrom_end, _flash_start, _flash_end;

static void ConfigClocks(void)
{
    // we are using a 16 MHz crystal as the basis for everything
    // slow clock runs at 32Khz typical regardless of crystal

    // enable system clock and USB clock
    AT91C_BASE_PMC->PMC_SCER = AT91C_PMC_PCK | AT91C_PMC_UDP;

	// enable the clock to the following peripherals
    AT91C_BASE_PMC->PMC_PCER =
		(1<<AT91C_ID_PIOA)	|
		(1<<AT91C_ID_ADC)	|
		(1<<AT91C_ID_SPI)	|
		(1<<AT91C_ID_SSC)	|
		(1<<AT91C_ID_PWMC)	|
		(1<<AT91C_ID_UDP);

	// worst case scenario, with MAINCK = 16Mhz xtal, startup delay is 1.4ms
	// if SLCK slow clock runs at its worst case (max) frequency of 42khz
	// max startup delay = (1.4ms*42k)/8 = 7.356 so round up to 8

	// enable main oscillator and set startup delay
    AT91C_BASE_PMC->PMC_MOR =
        AT91C_CKGR_MOSCEN |
        PMC_MAIN_OSC_STARTUP_DELAY(8);

	// wait for main oscillator to stabilize
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS) )
		;

    // PLL output clock frequency in range  80 - 160 MHz needs CKGR_PLL = 00
    // PLL output clock frequency in range 150 - 180 MHz needs CKGR_PLL = 10
    // PLL output is MAINCK * multiplier / divisor = 16Mhz * 12 / 2 = 96Mhz
    AT91C_BASE_PMC->PMC_PLLR =
    	PMC_PLL_DIVISOR(2) |
		PMC_PLL_COUNT_BEFORE_LOCK(0x50) |
		PMC_PLL_FREQUENCY_RANGE(0) |
		PMC_PLL_MULTIPLIER(12) |
		PMC_PLL_USB_DIVISOR(1);

	// wait for PLL to lock
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCK) )
		;

	// we want a master clock (MCK) to be PLL clock / 2 = 96Mhz / 2 = 48Mhz
	// datasheet recommends that this register is programmed in two operations
	// when changing to PLL, program the prescaler first then the source
    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2;

	// wait for main clock ready signal
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) )
		;

	// set the source to PLL
    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2 | AT91C_PMC_CSS_PLL_CLK;

	// wait for main clock ready signal
	while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) )
		;
}

static void Fatal(void)
{
  for(;;);
}

void UsbPacketReceived(uint8_t *packet, int len) {
  int i, dont_ack=0;
  UsbCommand* c = (UsbCommand *)packet;
  volatile uint32_t *p;
  
  if(len != sizeof(UsbCommand)) {
    Fatal();
  }
  
  uint32_t arg0 = (uint32_t)c->arg[0];
  
  switch(c->cmd) {
    case CMD_DEVICE_INFO: {
      dont_ack = 1;
      arg0 = DEVICE_INFO_FLAG_BOOTROM_PRESENT | DEVICE_INFO_FLAG_CURRENT_MODE_BOOTROM |
      DEVICE_INFO_FLAG_UNDERSTANDS_START_FLASH;
      if(common_area.flags.osimage_present) {
        arg0 |= DEVICE_INFO_FLAG_OSIMAGE_PRESENT;
      }
      cmd_send(CMD_DEVICE_INFO,arg0,1,2,0,0);
    } break;
      
    case CMD_SETUP_WRITE: {
      /* The temporary write buffer of the embedded flash controller is mapped to the
       * whole memory region, only the last 8 bits are decoded.
       */
      p = (volatile uint32_t *)&_flash_start;
      for(i = 0; i < 12; i++) {
        p[i+arg0] = c->d.asDwords[i];
      }
    } break;
      
    case CMD_FINISH_WRITE: {
      uint32_t* flash_mem = (uint32_t*)(&_flash_start);
      for (size_t j=0; j<2; j++) {
        for(i = 0+(64*j); i < 64+(64*j); i++) {
          flash_mem[i] = c->d.asDwords[i];
        }
        
        uint32_t flash_address = arg0 + (0x100*j);
        
        /* Check that the address that we are supposed to write to is within our allowed region */
        if( ((flash_address+AT91C_IFLASH_PAGE_SIZE-1) >= end_addr) || (flash_address < start_addr) ) {
          /* Disallow write */
          dont_ack = 1;
          cmd_send(CMD_NACK,0,0,0,0,0);
        } else {
          uint32_t page_n = (flash_address - ((uint32_t)flash_mem)) / AT91C_IFLASH_PAGE_SIZE;
          /* Translate address to flash page and do flash, update here for the 512k part */
          AT91C_BASE_EFC0->EFC_FCR = MC_FLASH_COMMAND_KEY |
          MC_FLASH_COMMAND_PAGEN(page_n) |
          AT91C_MC_FCMD_START_PROG;
        }
        
        // Wait until flashing of page finishes
        uint32_t sr;
        while(!((sr = AT91C_BASE_EFC0->EFC_FSR) & AT91C_MC_FRDY));
        if(sr & (AT91C_MC_LOCKE | AT91C_MC_PROGE)) {
          dont_ack = 1;
          cmd_send(CMD_NACK,0,0,0,0,0);
        }
      }
    } break;
      
    case CMD_HARDWARE_RESET: {
      usb_disable();
      AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY | AT91C_RSTC_PROCRST;
    } break;
      
    case CMD_START_FLASH: {
      if(c->arg[2] == START_FLASH_MAGIC) bootrom_unlocked = 1;
      else bootrom_unlocked = 0;
      {
        int prot_start = (int)&_bootrom_start;
        int prot_end = (int)&_bootrom_end;
        int allow_start = (int)&_flash_start;
        int allow_end = (int)&_flash_end;
        int cmd_start = c->arg[0];
        int cmd_end = c->arg[1];
        
        /* Only allow command if the bootrom is unlocked, or the parameters are outside of the protected
         * bootrom area. In any case they must be within the flash area.
         */
        if( (bootrom_unlocked || ((cmd_start >= prot_end) || (cmd_end < prot_start)))
           && (cmd_start >= allow_start) && (cmd_end <= allow_end) ) {
          start_addr = cmd_start;
          end_addr = cmd_end;
        } else {
          start_addr = end_addr = 0;
          dont_ack = 1;
          cmd_send(CMD_NACK,0,0,0,0,0);
        }
      }
    } break;
      
    default: {
      Fatal();
    } break;
  }
  
  if(!dont_ack) {
    cmd_send(CMD_ACK,arg0,0,0,0,0);
  }
}

static void flash_mode(int externally_entered)
{
	start_addr = 0;
	end_addr = 0;
	bootrom_unlocked = 0;
  byte_t rx[sizeof(UsbCommand)];
	size_t rx_len;

  usb_enable();
  for (volatile size_t i=0; i<0x100000; i++);

	for(;;) {
		WDT_HIT();

    if (usb_poll()) {
      rx_len = usb_read(rx,sizeof(UsbCommand));
      if (rx_len) {
        UsbPacketReceived(rx,rx_len);
      }
    }

		if(!externally_entered && !BUTTON_PRESS()) {
			/* Perform a reset to leave flash mode */
      usb_disable();
			LED_B_ON();
			AT91C_BASE_RSTC->RSTC_RCR = RST_CONTROL_KEY | AT91C_RSTC_PROCRST;
			for(;;);
		}
		if(externally_entered && BUTTON_PRESS()) {
			/* Let the user's button press override the automatic leave */
			externally_entered = 0;
		}
	}
}

extern uint32_t _osimage_entry;
void BootROM(void)
{
    //------------
    // First set up all the I/O pins; GPIOs configured directly, other ones
    // just need to be assigned to the appropriate peripheral.

    // Kill all the pullups, especially the one on USB D+; leave them for
    // the unused pins, though.
    AT91C_BASE_PIOA->PIO_PPUDR =
    	GPIO_USB_PU			|
		GPIO_LED_A			|
		GPIO_LED_B			|
		GPIO_LED_C			|
		GPIO_LED_D			|
		GPIO_FPGA_DIN		|
		GPIO_FPGA_DOUT		|
		GPIO_FPGA_CCLK		|
		GPIO_FPGA_NINIT		|
		GPIO_FPGA_NPROGRAM	|
		GPIO_FPGA_DONE		|
		GPIO_MUXSEL_HIPKD	|
		GPIO_MUXSEL_HIRAW	|
		GPIO_MUXSEL_LOPKD	|
		GPIO_MUXSEL_LORAW	|
		GPIO_RELAY			|
		GPIO_NVDD_ON;
		// (and add GPIO_FPGA_ON)
	// These pins are outputs
    AT91C_BASE_PIOA->PIO_OER =
    	GPIO_LED_A			|
		GPIO_LED_B			|
		GPIO_LED_C			|
		GPIO_LED_D			|
		GPIO_RELAY			|
		GPIO_NVDD_ON;
	// PIO controls the following pins
    AT91C_BASE_PIOA->PIO_PER =
    	GPIO_USB_PU			|
		GPIO_LED_A			|
		GPIO_LED_B			|
		GPIO_LED_C			|
		GPIO_LED_D;

//    USB_D_PLUS_PULLUP_OFF();
  usb_disable();
    LED_D_OFF();
    LED_C_ON();
    LED_B_OFF();
    LED_A_OFF();

	AT91C_BASE_EFC0->EFC_FMR =
		AT91C_MC_FWS_1FWS |
		MC_FLASH_MODE_MASTER_CLK_IN_MHZ(48);

    // Initialize all system clocks
    ConfigClocks();

    LED_A_ON();

    int common_area_present = 0;
    switch(AT91C_BASE_RSTC->RSTC_RSR & AT91C_RSTC_RSTTYP) {
    case AT91C_RSTC_RSTTYP_WATCHDOG:
    case AT91C_RSTC_RSTTYP_SOFTWARE:
    case AT91C_RSTC_RSTTYP_USER:
	    /* In these cases the common_area in RAM should be ok, retain it if it's there */
	    if(common_area.magic == COMMON_AREA_MAGIC && common_area.version == 1) {
		    common_area_present = 1;
	    }
	    break;
    default: /* Otherwise, initialize it from scratch */
	    break;
    }

    if(!common_area_present){
	    /* Common area not ok, initialize it */
	    int i; for(i=0; i<sizeof(common_area); i++) { /* Makeshift memset, no need to drag util.c into this */
		    ((char*)&common_area)[i] = 0;
	    }
	    common_area.magic = COMMON_AREA_MAGIC;
	    common_area.version = 1;
	    common_area.flags.bootrom_present = 1;
    }

    common_area.flags.bootrom_present = 1;
    if(common_area.command == COMMON_AREA_COMMAND_ENTER_FLASH_MODE) {
	    common_area.command = COMMON_AREA_COMMAND_NONE;
	    flash_mode(1);
    } else if(BUTTON_PRESS()) {
	    flash_mode(0);
    } else if(_osimage_entry == 0xffffffffU) {
	    flash_mode(1);
    } else {
	    // jump to Flash address of the osimage entry point (LSBit set for thumb mode)
	    __asm("bx %0\n" : : "r" ( ((int)&_osimage_entry) | 0x1 ) );
    }
}
