ra8_bkup_security.c

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#include <stdint.h>
 
#include "ra8_attributes.h"
#include "ra8_bkup.h"
#include "ra8_bkup_internal.h"
#include "ra8_bkup_regs.h"
#include "ra8_check.h"
#include "ra8_err.h"
#include "ra8_register_protection.h"
 
/* =============================================================================
 * Internal helpers
 * =============================================================================
 */

RA8_INTERNAL static ra8_err_t internal_validate_boundary(uint16_t addr)
{
  if ((addr & k_ra8_bkup_saba_align_mask) != 0U) {
    return k_ra8_err_invalid_arg;
  }
  if (addr > k_ra8_bkup_saba_max) {
    return k_ra8_err_invalid_arg;
  }
  return k_ra8_ok;
}

RA8_INTERNAL static ra8_err_t internal_validate_security_cfg(const ra8_bkup_security_config_t* cfg)
{
  if ((cfg->bbfsar & ~k_ra8_bkup_bbfsar_mask_all) != 0U) {
    return k_ra8_err_invalid_arg;
  }
  ra8_err_t err = internal_validate_boundary(cfg->saba);
  RA8_RETURN_ON_ERROR(err, g_bkup_tag, "security_apply: saba bad");
  err = internal_validate_boundary(cfg->pabas);
  RA8_RETURN_ON_ERROR(err, g_bkup_tag, "security_apply: pabas bad");
  err = internal_validate_boundary(cfg->pabans);
  RA8_RETURN_ON_ERROR(err, g_bkup_tag, "security_apply: pabans bad");
  return k_ra8_ok;
}
 
/* =============================================================================
 * TrustZone partitioning
 * =============================================================================
 */
 
[[nodiscard]] ra8_err_t ra8_bkup_security_apply(const ra8_bkup_security_config_t* cfg)
{
  RA8_CHECK_NULL_PTR(cfg, g_bkup_tag, "security cfg must not be nullptr");
  const ra8_err_t v_err = internal_validate_security_cfg(cfg);
  RA8_RETURN_ON_ERROR(v_err, g_bkup_tag, "security_apply: cfg bad");
 
  /* BBFSAR / VBRSABAR / VBRPABARS / VBRPABARNS are security-attribution
   * registers, so they sit behind PRC4 -- not the PRC1 that guards the rest
   * of this block (HUM Ch 13.1 Table 13.1 p 521). */
  RA8_PROTECTED_WRITE(k_ra8_prcr_unlock_sar)
  {
    /* HUM Ch 12.2.1 "BBFSAR : Battery Backup Function Security Attribute Register", p 500 */
    *ra8_bkup_bbfsar() = (uint32_t)(cfg->bbfsar & k_ra8_bkup_bbfsar_mask_all);
    /* HUM Ch 12.2.2 "VBRSABAR : VBATT Backup Register Security Attribute Boundary Address Register", p 502 */
    *ra8_bkup_vbrsabar() = cfg->saba;
    /* HUM Ch 12.2.3 "VBRPABARS : VBATT Backup Register Privilege Attribute Boundary Address Register for Secure Region", p 502 */
    *ra8_bkup_vbrpabars() = cfg->pabas;
    /* HUM Ch 12.2.4 "VBRPABARNS : VBATT Backup Register Privilege Attribute Boundary Address Register for Non-secure Region", p 503 */
    *ra8_bkup_vbrpabarns() = cfg->pabans;
  }
  return k_ra8_ok;
}
 
[[nodiscard]] ra8_err_t ra8_bkup_security_get(ra8_bkup_security_config_t* cfg)
{
  RA8_CHECK_NULL_PTR(cfg, g_bkup_tag, "security cfg must not be nullptr");
  /* HUM Ch 12.2.1 "BBFSAR : Battery Backup Function Security Attribute Register", p 500 */
  cfg->bbfsar = (uint32_t)(*ra8_bkup_bbfsar() & k_ra8_bkup_bbfsar_mask_all);
  /* HUM Ch 12.2.2 "VBRSABAR : VBATT Backup Register Security Attribute Boundary Address Register", p 502 */
  cfg->saba = *ra8_bkup_vbrsabar();
  /* HUM Ch 12.2.3 "VBRPABARS : VBATT Backup Register Privilege Attribute Boundary Address Register for Secure Region", p 502 */
  cfg->pabas = *ra8_bkup_vbrpabars();
  /* HUM Ch 12.2.4 "VBRPABARNS : VBATT Backup Register Privilege Attribute Boundary Address Register for Non-secure Region", p 503 */
  cfg->pabans = *ra8_bkup_vbrpabarns();
  return k_ra8_ok;
}