lpc55s69 hw crypto by twcook86 · Pull Request #757 · wolfSSL/wolfBoot

twcook86 · 2026-04-22T01:27:21Z

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Pull request overview

Note

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Adds LPC55S69 hardware-crypto enablement and supporting tooling for flashing/debug plus wolfCrypt test/benchmark support on the test application.

Changes:

Add Lauterbach .cmm scripts for factory flashing, update-image flashing, and debug setup.
Enable/parameterize LPC55S69 crypto acceleration build knobs (PKA), RNG/HashCrypt/Casper integration, and wolfCrypt test/benchmark execution.
Update LPC55S69 linker/config defaults (RAM size, partitions, hash algorithm) to accommodate new crypto/test needs.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
tools/scripts/lpc55s69/lpc55s69_flash_update.cmm	Adds Lauterbach script to program a signed update image.
tools/scripts/lpc55s69/lpc55s69_flash_factory_bin.cmm	Adds Lauterbach script to erase and flash a factory image.
tools/scripts/lpc55s69/lpc55s69_debug.cmm	Adds Lauterbach script to load symbols and set breakpoints for debugging.
test-app/wolfcrypt_support.c	Uses LPC55S69 SysTick millisecond counter for timing APIs used by wolfCrypt tests/benchmarks.
test-app/syscalls.c	Adds `vsnprintf` forward declaration to route printf-family functions.
test-app/startup_arm.c	Maps SysTick ISR name for LPC55S69 builds.
test-app/app_lpc55s69.c	Adds SysTick timebase, wolfCrypt test/benchmark runner, and weak syscall stubs.
test-app/Makefile	Adds RSA object and LPC55S69 hardware-crypto build/ld flags (PKA vs no-hwaccel).
test-app/ARM-lpc55s69.ld	Increases RAM, adds heap/stack region symbols used by runtime/debug.
include/user_settings.h	Adjusts RNG/DRBG and cipher settings for LPC55S69 (incl. interleave limitation).
hal/lpc55s69.c	Initializes HashCrypt/Casper and adjusts RNG peripheral handling based on hwaccel macros.
config/examples/lpc55s69.config	Updates defaults (SHA256, PKA off, partition locations) and documents larger-sector option.
config/examples/lpc55s69-tz.config	Same as above for TZ build.
arch.mk	Adds include paths and objects for LPC55S69 Casper/HashCrypt/RNG under PKA builds.

Comments suppressed due to low confidence (1)

hal/lpc55s69.c:1

The return values of wc_hashcrypt_init() / wc_casper_init() are ignored. If initialization fails (clocking, reset state, secure/non-secure access, etc.), later crypto operations may fail in harder-to-debug ways. Recommend checking the return codes and either logging (when DEBUG_UART) and/or failing fast in a controlled way.

/* lpc55s69.c

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Copilot · 2026-04-22T17:45:33Z

+DO ~~/demo/arm/flash/lpc55xx PREPAREONLY
+
+;; flash.erase all ;; NOT FOR UPDATE
+FLASH.ReProgram ALL
+Data.LOAD.Binary "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf\wolfBoot\test-app\image_v2_signed.bin" 0x18000


This hard-codes a developer-specific WSL UNC path (including username and distro). Consider parameterizing the image path (e.g., via a CMM variable / argument / prompt) or using a repository-relative path so the script is reproducible across environments.

Suggested change

DO ~~/demo/arm/flash/lpc55xx PREPAREONLY

;; flash.erase all ;; NOT FOR UPDATE

FLASH.ReProgram ALL

Data.LOAD.Binary "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf\wolfBoot\test-app\image_v2_signed.bin" 0x18000

LOCAL &image_path

ENTRY &image_path

IF "&image_path"==""

(

ENTER &image_path "Path to signed image binary"

)

DO ~~/demo/arm/flash/lpc55xx PREPAREONLY

;; flash.erase all ;; NOT FOR UPDATE

FLASH.ReProgram ALL

Data.LOAD.Binary "&image_path" 0x18000

Copilot · 2026-04-22T17:45:33Z

+
+flash.erase all
+FLASH.ReProgram ALL
+Data.LOAD.Binary "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf\wolfBoot\factory.bin" 0


This hard-codes a developer-specific WSL UNC path. Recommend making the binary path an input parameter (or using a relative path) so the factory flashing script can be used in CI/docs and by other developers without edits.

Copilot · 2026-04-22T17:45:34Z

+data.load "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf\wolfBoot\wolfboot.elf" /nocode
+symbol.sourcepath.TranslateSUBpath "\home\tcook\wolf" "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf"


The debug script bakes in a specific local filesystem layout (WSL path + home directory). This will fail for anyone else and is difficult to automate. Consider using parameterized paths (passed in at invocation time) or deriving paths from the script location to make debugging setup portable.

Copilot · 2026-04-22T17:45:34Z

 * other OS facilities that don't exist in bare-metal.
 * wolfCrypt test/benchmark code calls standard printf, not wolfBoot_printf.
 */
+int vsnprintf(char *buf, unsigned int size, const char *fmt, va_list argp);


This forward declaration does not match the standard vsnprintf signature (uses unsigned int instead of size_t, and may conflict with the libc prototype). This can cause compile warnings/errors or ABI mismatches. Prefer including the proper header and not redeclaring it, or match the exact standard prototype (size_t-based) consistently.

Copilot · 2026-04-22T17:45:34Z

+void WEAKFUNCTION *_sbrk(int incr)
+{
+    (void)incr;
+    return 0;
+}


_sbrk returning 0 unconditionally is unsafe: allocators may treat 0 as a valid heap pointer and proceed, leading to writes to address 0 and hard faults. Either implement _sbrk using linker-provided heap/stack bounds (_start_heap, _end_stack) or fail correctly by returning (void*)-1 and setting errno to ENOMEM.

Copilot · 2026-04-22T17:45:35Z

  APP_OBJS+=$(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/sp_c32.o

+  # Add RSA support (needed by test suite)
+  APP_OBJS+=$(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/rsa.o


RSA is being linked whenever WOLFCRYPT_SUPPORT=1, but the comment indicates it’s only needed for the test suite. Consider gating rsa.o under WOLFCRYPT_TEST (and/or WOLFCRYPT_BENCHMARK if required) to avoid unnecessary code size in non-test builds.

Suggested change

APP_OBJS+=$(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/rsa.o

ifeq ($(WOLFCRYPT_TEST),1)

APP_OBJS+=$(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/rsa.o

endif

Copilot · 2026-04-22T17:45:35Z

 #ifdef WOLFCRYPT_SECURE_MODE
 void hal_trng_init(void)
 {
-#ifdef __WOLFBOOT
+#ifndef WOLFSSL_NXP_LPC55S69_NO_HWACCEL
+# ifdef __WOLFBOOT
    CLOCK_EnableClock(kCLOCK_Rng);
    RESET_PeripheralReset(kRNG_RST_SHIFT_RSTn);
-#endif
+# endif
    RNG_Init(RNG);
+#endif
 }


When WOLFSSL_NXP_LPC55S69_NO_HWACCEL is defined, TRNG init becomes a no-op and hal_trng_get_entropy() deterministically returns -1. In WOLFCRYPT_SECURE_MODE, that likely breaks any code requiring entropy (and can silently downgrade security if callers don’t handle it). Consider decoupling TRNG availability from the 'no hw accel' macro (RNG is not the same as Casper/HashCrypt), or emit a compile-time error if secure mode is enabled without a usable entropy source.

Copilot · 2026-04-22T17:45:35Z

 int hal_trng_get_entropy(unsigned char *out, unsigned int len)
 {
+#ifndef WOLFSSL_NXP_LPC55S69_NO_HWACCEL
    if (RNG_GetRandomData(RNG, out, len) == kStatus_Success)
        return 0;
+#endif

    return -1;
 }


When WOLFSSL_NXP_LPC55S69_NO_HWACCEL is defined, TRNG init becomes a no-op and hal_trng_get_entropy() deterministically returns -1. In WOLFCRYPT_SECURE_MODE, that likely breaks any code requiring entropy (and can silently downgrade security if callers don’t handle it). Consider decoupling TRNG availability from the 'no hw accel' macro (RNG is not the same as Casper/HashCrypt), or emit a compile-time error if secure mode is enabled without a usable entropy source.

Copilot · 2026-04-22T17:45:36Z

 FLASH_MULTI_SECTOR_ERASE?=1

-# 512-byte pages erasable/writeable
+# use 1024-byte sector to accomodate RSA4096 signature


Correct typo: 'accomodate' should be 'accommodate'.

Suggested change

# use 1024-byte sector to accomodate RSA4096 signature

# use 1024-byte sector to accommodate RSA4096 signature

Copilot · 2026-04-22T17:45:36Z

 WOLFCRYPT_TZ_PKCS11?=1

-# 512-byte pages erasable/writeable
+# use 1024-byte sector to accomodate RSA4096 signature


Correct typo: 'accomodate' should be 'accommodate'.

Suggested change

# use 1024-byte sector to accomodate RSA4096 signature

# use 1024-byte sector to accommodate RSA4096 signature

danielinux

do not tie RNG to NO_HWACCEL. CASPER/HASHCRYPT acceleration can be disabled while the hardware RNG is still required by WOLFCRYPT_SECURE_MODE, e.g. when compiling with trustzone.

You still need something like:

  ifeq ($(WOLFCRYPT_TZ),1)
    OBJS+=$(MCUXPRESSO)/drivers/rng_1/fsl_rng.o
  endif

when PKA=0.

Then in hal/lpc55s69.c, you should remove the WOLFSSL_NXP_LPC55S69_NO_HWACCEL guards around RNG_Init() and RNG_GetRandomData(), or replace them with a dedicated RNG macro if you need one

twcook86 added 11 commits March 26, 2026 16:56

Add hw support for SHA1 and SHA256

b6afd80

Bump up sector size to accomodate rsa4096

2b5aa3e

initialize casper for rsa signing

a8a8961

Better hook rng into wolfCrypt

687aafe

Add benchmark and test capability to test-app

0a3c40a

fix build flags for hw accel

4e54f8e

turn on other aes algs for test/benchmark

3dff225

Regression test fixes

2e0412d

Merge branch 'master' into lpc55s69_crypto

d0f7f76

Add lauterbach scripts

a3bff94

Turn off lpc55s69 hw accel (PKA) be default

cc5d8ff

twcook86 requested a review from danielinux April 22, 2026 17:35

danielinux requested a review from Copilot April 22, 2026 17:37

danielinux self-assigned this Apr 22, 2026

Copilot AI reviewed Apr 22, 2026

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danielinux requested changes Apr 22, 2026

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Copilot started reviewing on behalf of danielinux April 22, 2026 17:50 View session

danielinux assigned twcook86 Apr 22, 2026

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lpc55s69 hw crypto#757

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twcook86 wants to merge 11 commits intowolfSSL:masterfrom
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		data.load "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf\wolfBoot\wolfboot.elf" /nocode
		symbol.sourcepath.TranslateSUBpath "\home\tcook\wolf" "\\wsl.localhost\Ubuntu-22.04\home\tcook\wolf"

	# use 1024-byte sector to accomodate RSA4096 signature
	# use 1024-byte sector to accommodate RSA4096 signature

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