path: root/src/stm32/modexpa7_driver_sample.c

/*
 * modexpa7_driver_sample.c
 * ----------------------------------------------
 * Demo program to test ModExpA7 core in hardware
 *
 * Authors: Pavel Shatov
 * Copyright (c) 2017, NORDUnet A/S
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the NORDUnet nor the names of its contributors may
 *   be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
		/*
		 * Note, that the test program needs a custom bitstream without
		 * the core selector, where the DUT is at offset 0.
		 */

		// stm32 headers
#include "stm-init.h"
#include "stm-led.h"
#include "stm-fmc.h"

		// test vectors
#include "test/modexp_fpga_model_vectors.h"

		// locations of core registers
#define CORE_ADDR_NAME0						(0x00 << 2)
#define CORE_ADDR_NAME1						(0x01 << 2)
#define CORE_ADDR_VERSION					(0x02 << 2)
#define CORE_ADDR_CONTROL					(0x08 << 2)
#define CORE_ADDR_STATUS					(0x09 << 2)
#define CORE_ADDR_MODE						(0x10 << 2)
#define CORE_ADDR_MODULUS_BITS		(0x11 << 2)
#define CORE_ADDR_EXPONENT_BITS		(0x12 << 2)
#define CORE_ADDR_BUFFER_BITS			(0x13 << 2)
#define CORE_ADDR_ARRAY_BITS			(0x14 << 2)


		// locations of operand buffers
#define CORE_ADDR_BANK_MODULUS		(0x800 + 0 * 0x200)
#define CORE_ADDR_BANK_MESSAGE		(0x800 + 1 * 0x200)
#define CORE_ADDR_BANK_EXPONENT		(0x800 + 2 * 0x200)
#define CORE_ADDR_BANK_RESULT			(0x800 + 3 * 0x200)

		// bit maps
#define CORE_CONTROL_BIT_INIT		0x00000001
#define CORE_CONTROL_BIT_NEXT		0x00000002

#define CORE_STATUS_BIT_READY		0x00000001
#define CORE_STATUS_BIT_VALID		0x00000002

#define CORE_MODE_BIT_CRT				0x00000002


		/*
		 * test vectors
		 */
static const uint32_t m_384[]	= M_384;
static const uint32_t n_384[]	= N_384;
static const uint32_t d_384[]	= D_384;
static const uint32_t s_384[]	= S_384;

static const uint32_t m_512[]	= M_512;
static const uint32_t n_512[]	= N_512;
static const uint32_t d_512[]	= D_512;
static const uint32_t s_512[]	= S_512;


		/*
		 * prototypes
		 */
void toggle_yellow_led(void);

void setup_modexpa7(	const uint32_t *n, size_t l);

int test_modexpa7(		const uint32_t *m,
											const uint32_t *d,
											const uint32_t *s,
											      size_t    l);


		/*
		 * test routine
		 */
int main()
{
		int ok;
	
    stm_init();
    fmc_init();
	
				// turn on the green led
    led_on(LED_GREEN);
    led_off(LED_RED);
    led_off(LED_YELLOW);
    led_off(LED_BLUE);

				// check, that core is present
		uint32_t core_name0;
		uint32_t core_name1;
		uint32_t core_version;
	
		fmc_read_32(CORE_ADDR_NAME0,   &core_name0);
		fmc_read_32(CORE_ADDR_NAME1,   &core_name1);
		fmc_read_32(CORE_ADDR_VERSION, &core_version);
			
				// must be "mode", "xpa7", "0.20"
		if (	(core_name0   != 0x6D6F6465) ||
					(core_name1   != 0x78706137) ||
					(core_version != 0x302E3230))
		{
				led_off(LED_GREEN);
				led_on(LED_RED);
				while (1);
		}

				// read compile-time settings
		uint32_t core_buffer_bits;
		uint32_t core_array_bits;
	
			// largest supported operand width, systolic array "power"
		fmc_read_32(CORE_ADDR_BUFFER_BITS, &core_buffer_bits);
		fmc_read_32(CORE_ADDR_ARRAY_BITS,  &core_array_bits);		
		
			// repeat forever
		while (1)
		{
						// New modulus requires precomputation of modulus-dependent
						// speed-up coefficient, this must be done once per new
						// modulus, i.e. when we're repeatedly signing with the
						// same key, we only need to do precomputation once before
						// starting the very first signing operation.
			
						// fresh start
				ok = 1;
			
				{
								// run precomputation of modulus-dependent factor for the 384-bit modulus
						setup_modexpa7(n_384, 384);
			
								// try signing the message from the 384-bit test vector
						ok = ok && test_modexpa7(m_384, d_384, s_384, 384);
				}
				{
								// run precomputation of modulus-dependent factor for the 512-bit modulus
						setup_modexpa7(n_512, 512);
			
								// try signing the message from the 512-bit test vector
						ok = ok && test_modexpa7(m_512, d_512, s_512, 512);
				}
			
						// turn on the red led to indicate something went wrong
				if (!ok)
				{		led_off(LED_GREEN);
						led_on(LED_RED);
				}
				
						// indicate, that we're alive doing something...
				toggle_yellow_led();
		}
}


		/*
		 * Load new modulus and do the necessary precomputations.
		 */
void setup_modexpa7(	const uint32_t *n,
										        size_t    l)
{
		size_t i, num_words;
		uint32_t num_bits;
		uint32_t reg_control, reg_status;
		uint32_t n_word;
		uint32_t dummy_num_cyc;		
	
			// determine numbers of 32-bit words
		num_words = l >> 5;
	
			// set modulus width
		num_bits = l;
		fmc_write_32(CORE_ADDR_MODULUS_BITS,  &num_bits);
	
			// fill modulus bank (the least significant word
			// is at the lowest offset)
		for (i=0; i<num_words; i++)
		{		n_word = n[i];
				fmc_write_32(CORE_ADDR_BANK_MODULUS  + ((num_words - (i + 1)) * sizeof(uint32_t)), &n_word);
		}

				// clear 'init' control bit, then set 'init' control bit again
				// to trigger precomputation (core is edge-triggered)
		reg_control = 0;
		fmc_write_32(CORE_ADDR_CONTROL, &reg_control);
		reg_control = CORE_CONTROL_BIT_INIT;
		fmc_write_32(CORE_ADDR_CONTROL, &reg_control);
	
				// wait for 'ready' status bit to be set
		dummy_num_cyc = 0;
		do
		{		dummy_num_cyc++;
				fmc_read_32(CORE_ADDR_STATUS, &reg_status);
		}
		while (!(reg_status & CORE_STATUS_BIT_READY));
}


		//
		// Sign the message and compare it against the correct reference value.
		//
int test_modexpa7(	const uint32_t *m,
										const uint32_t *d,
										const uint32_t *s,
										      size_t    l)
{
		size_t i, num_words;
		uint32_t num_bits;
		uint32_t reg_control, reg_status;
		uint32_t m_word, d_word, s_word;
		uint32_t dummy_num_cyc;		
		
				// determine numbers of 32-bit words
		num_words = l >> 5;
	
				// set exponent width
		num_bits = l;
		fmc_write_32(CORE_ADDR_EXPONENT_BITS,  &num_bits);
	
				// fill modulus bank (the least significant word
				// is at the lowest offset)
		for (i=0; i<num_words; i++)
		{		m_word = m[i];
				d_word = d[i];
				fmc_write_32(CORE_ADDR_BANK_MESSAGE  + ((num_words - (i + 1)) * sizeof(uint32_t)), &m_word);
				fmc_write_32(CORE_ADDR_BANK_EXPONENT + ((num_words - (i + 1)) * sizeof(uint32_t)), &d_word);
		}

				// clear 'next' control bit, then set 'next' control bit again
				// to trigger exponentiation (core is edge-triggered)
		reg_control = 0;
		fmc_write_32(CORE_ADDR_CONTROL, &reg_control);
		reg_control = CORE_CONTROL_BIT_NEXT;
		fmc_write_32(CORE_ADDR_CONTROL, &reg_control);
	
				// wait for 'valid' status bit to be set
		dummy_num_cyc = 0;
		do
		{		dummy_num_cyc++;
				fmc_read_32(CORE_ADDR_STATUS, &reg_status);
		}
		while (!(reg_status & CORE_STATUS_BIT_VALID));
		
				// read back the result word-by-word, then compare to the reference values
		for (i=0; i<num_words; i++)
		{		
				fmc_read_32(CORE_ADDR_BANK_RESULT + (i * sizeof(uint32_t)), &s_word);
			
				if (s_word != s[num_words - (i + 1)])
					return 0;
		}
	
				// everything went just fine
		return 1;
}


		//
		// toggle the yellow led to indicate that we're not stuck somewhere
		//
void toggle_yellow_led(void)
{
		static int led_state = 0;
	
		led_state = !led_state;
	
		if (led_state) led_on(LED_YELLOW);
		else           led_off(LED_YELLOW);
}


		//
		// end of file
		//