Dear TF-M developers

Hello, i'm developing and porting TF-M our platforms based on RDV3R1.

To enable TRAM, i modified a cmake config file like below(platform/ext/target/arm/rse/common/config.cmake)

- set(RSE_ENABLE_TRAM                     OFF       CACHE BOOL "Whether TRAM encryption is enabled")

+ set(RSE_ENABLE_TRAM                     ON       CACHE BOOL "Whether TRAM encryption is enabled")

First of all, RSE core boots with Virgin CM 

In this mode, Secure Provisioning is not enabled so that the DTCM don't be initialized even if TRAM is enabled. 

setup_tram_encryption()@startup_rse_bl1_1.c

    tram_enable_encryption(&tram_dev_s);

    if (sp_enabled == LCM_TRUE && (lcs == LCM_LCS_CM || lcs == LCM_LCS_DM)) {

        bl1_trng_generate_random((uint8_t *)&random_word, sizeof(random_word));

        for (idx = 0; idx < DTCM_SIZE / sizeof(uint32_t); idx++) {

            ((uint32_t *)DTCM_BASE_S)[idx] = random_word;

        }

    }

Because DTCM doesn't be initialized, the next codes which use global variable in BL1_1 data section on DTCM cause hardfault.

So, i applied the workaround by modifying condition like below.

    tram_enable_encryption(&tram_dev_s);

-    if (sp_enabled == LCM_TRUE && (lcs == LCM_LCS_CM || lcs == LCM_LCS_DM)) {

+   if ((lcs == LCM_LCS_CM || lcs == LCM_LCS_DM)) {

        bl1_trng_generate_random((uint8_t *)&random_word, sizeof(random_word));

        for (idx = 0; idx < DTCM_SIZE / sizeof(uint32_t); idx++) {

            ((uint32_t *)DTCM_BASE_S)[idx] = random_word;

        }

    }

But the global variable in uninitialized DTCM are also used in bl1_trng_generate_random().

So, i tried to initialize DTCM as 0 without calling bl1_trng_generate_random(). 

But after that, setting SP_ENABLED for CM Provisioning causes warm reset, TRAM is disabled but DTCM doesn't be initialized.

It causes same problem.

I know that enabling TRAM is performed DMA descriptor without RSE_ENABLE_TRAM option, it may also cause the problem because of the phenomenon that TRAM is disabled but DTCM doesn't be initialized when warm reset.

Should i modify let it use local variable?  or is there anything to fix this problem?

Best Regards

RH Kim