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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Tiny charger configuration */
#include "common.h"
#include "debug.h"
#include "ec_commands.h"
#include "registers.h"
#include "rsa.h"
#include "sha256.h"
#include "system.h"
#include "task.h"
#include "usb_pd.h"
#include "util.h"
#include "version.h"
/* Insert the RSA public key definition */
const struct rsa_public_key pkey __attribute__((section(".rsa_pubkey"))) =
#include "gen_pub_key.h"
/* The RSA signature is stored at the end of the RW firmware */
static const void *rw_sig = (void *)CONFIG_FLASH_BASE + CONFIG_FW_RW_OFF
+ CONFIG_FW_RW_SIZE - RSANUMBYTES;
/* Large 768-Byte buffer for RSA computation : could be re-use afterwards... */
static uint32_t rsa_workbuf[3 * RSANUMWORDS];
extern void pd_rx_handler(void);
/* RW firmware reset vector */
static uint32_t * const rw_rst =
(uint32_t *)(CONFIG_FLASH_BASE+CONFIG_FW_RW_OFF+4);
/* External interrupt EXTINT7 for external comparator on PA7 */
void pd_rx_interrupt(void)
{
/* trigger reception handling */
pd_rx_handler();
}
DECLARE_IRQ(STM32_IRQ_EXTI4_15, pd_rx_interrupt, 1);
static void jump_to_rw(void)
{
void (*jump_rw_rst)(void) = (void *)*rw_rst;
debug_printf("Jump to RW\n");
/* Disable interrupts */
asm volatile("cpsid i");
/* Call RW firmware reset vector */
jump_rw_rst();
}
int is_ro_mode(void)
{
return (uint32_t)&jump_to_rw < (uint32_t)rw_rst;
}
static int check_rw_valid(void *rw_hash)
{
int good;
/* Check if we have a RW firmware flashed */
if (*rw_rst == 0xffffffff)
return 0;
good = rsa_verify(&pkey, (void *)rw_sig, rw_hash, rsa_workbuf);
if (!good) {
debug_printf("RSA FAILED\n");
pd_log_event(PD_EVENT_ACC_RW_FAIL, 0, 0, NULL);
return 0;
}
return 1;
}
extern void pd_task(void);
int main(void)
{
void *rw_hash;
hardware_init();
debug_printf("%s started\n",
is_ro_mode() ? "RO" : "RW");
/* the RO partition protection is not enabled : do it */
if (!flash_physical_is_permanently_protected())
flash_physical_permanent_protect();
/*
* calculate the hash of the RW partition
*
* Also pre-cache it so we can answer Discover Identity VDM
* fast enough (in less than 30ms).
*/
rw_hash = flash_hash_rw();
/* Verify RW firmware and use it if valid */
if (is_ro_mode() && check_rw_valid(rw_hash))
jump_to_rw();
/* background loop for PD events */
pd_task();
debug_printf("EXIT!\n");
/* we should never reach that point */
system_reset(0);
return 0;
}
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