flash/stm32l4x: introduce 'stm32l4x trustzone [enable|disable]' command

this command will help to enable/disable or display the TrustZone security,
using the TZEN option bit.

Note: This command works only with devices with TrustZone, eg. STM32L5.
Note: This command will perform an OBL_Launch after modifying the TZEN.

Change-Id: I4aef15bf57d09c1658d37858143d23b1d43de1f0
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/5542
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

diff --git a/doc/openocd.texi b/doc/openocd.texi
index 340e6b65b025a05a77487ff6c011a6e6d3f5a14a..33812499ac4dbff6cbbb4e0234469468ae5ee297 100644 (file)
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -7400,6 +7400,14 @@ write protected areas in a specific @var{device_bank}
 Forces a re-load of the option byte registers. Will cause a system reset of the device.
 The @var{num} parameter is a value shown by @command{flash banks}.
 @end deffn
+
+@deffn Command {stm32l4x trustzone} num [@option{enable} | @option{disable}]
+Enables or disables Global TrustZone Security, using the TZEN option bit.
+If neither @option{enabled} nor @option{disable} are specified, the command will display
+the TrustZone status.
+@emph{Note:} This command works only with devices with TrustZone, eg. STM32L5.
+@emph{Note:} This command will perform an OBL_Launch after modifying the TZEN.
+@end deffn
 @end deffn
 
 @deffn {Flash Driver} {str7x}

diff --git a/src/flash/nor/stm32l4x.c b/src/flash/nor/stm32l4x.c
index 5287ff6b3a9b29378b63b7d9f76c444e8eb0b55b..6370d17becca58f0d19c26feaabe96ea01628a31 100644 (file)
--- a/src/flash/nor/stm32l4x.c
+++ b/src/flash/nor/stm32l4x.c
@@ -791,6 +791,42 @@ static int stm32l4_unlock_option_reg(struct flash_bank *bank)
        return ERROR_OK;
 }
 
+static int stm32l4_perform_obl_launch(struct flash_bank *bank)
+{
+       int retval, retval2;
+
+       retval = stm32l4_unlock_reg(bank);
+       if (retval != ERROR_OK)
+               goto err_lock;
+
+       retval = stm32l4_unlock_option_reg(bank);
+       if (retval != ERROR_OK)
+               goto err_lock;
+
+       /* Set OBL_LAUNCH bit in CR -> system reset and option bytes reload,
+        * but the RMs explicitly do *NOT* list this as power-on reset cause, and:
+        * "Note: If the read protection is set while the debugger is still
+        * connected through JTAG/SWD, apply a POR (power-on reset) instead of a system reset."
+        */
+
+       /* "Setting OBL_LAUNCH generates a reset so the option byte loading is performed under system reset" */
+       /* Due to this reset ST-Link reports an SWD_DP_ERROR, despite the write was successful,
+        * then just ignore the returned value */
+       stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_OBL_LAUNCH);
+
+       /* Need to re-probe after change */
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       stm32l4_info->probed = false;
+
+err_lock:
+       retval2 = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_LOCK | FLASH_OPTLOCK);
+
+       if (retval != ERROR_OK)
+               return retval;
+
+       return retval2;
+}
+
 static int stm32l4_write_option(struct flash_bank *bank, uint32_t reg_offset,
        uint32_t value, uint32_t mask)
 {
@@ -1775,9 +1811,9 @@ COMMAND_HANDLER(stm32l4_handle_option_write_command)
        return retval;
 }
 
-COMMAND_HANDLER(stm32l4_handle_option_load_command)
+COMMAND_HANDLER(stm32l4_handle_trustzone_command)
 {
-       if (CMD_ARGC != 1)
+       if (CMD_ARGC < 1 || CMD_ARGC > 2)
                return ERROR_COMMAND_SYNTAX_ERROR;
 
        struct flash_bank *bank;
@@ -1785,28 +1821,78 @@ COMMAND_HANDLER(stm32l4_handle_option_load_command)
        if (retval != ERROR_OK)
                return retval;
 
-       retval = stm32l4_unlock_reg(bank);
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       if (!(stm32l4_info->part_info->flags & F_HAS_TZ)) {
+               LOG_ERROR("This device does not have a TrustZone");
+               return ERROR_FAIL;
+       }
+
+       uint32_t optr;
+       retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_OPTR_INDEX, &optr);
        if (retval != ERROR_OK)
                return retval;
 
-       retval = stm32l4_unlock_option_reg(bank);
+       stm32l4_sync_rdp_tzen(bank, optr);
+
+       if (CMD_ARGC == 1) {
+               /* only display the TZEN value */
+               LOG_INFO("Global TrustZone Security is %s", stm32l4_info->tzen ? "enabled" : "disabled");
+               return ERROR_OK;
+       }
+
+       bool new_tzen;
+       COMMAND_PARSE_ENABLE(CMD_ARGV[1], new_tzen);
+
+       if (new_tzen == stm32l4_info->tzen) {
+               LOG_INFO("The requested TZEN is already programmed");
+               return ERROR_OK;
+       }
+
+       if (new_tzen) {
+               if (stm32l4_info->rdp != RDP_LEVEL_0) {
+                       LOG_ERROR("TZEN can be set only when RDP level is 0");
+                       return ERROR_FAIL;
+               }
+               retval = stm32l4_write_option(bank, stm32l4_info->flash_regs[STM32_FLASH_OPTR_INDEX],
+                               FLASH_TZEN, FLASH_TZEN);
+       } else {
+               /* Deactivation of TZEN (from 1 to 0) is only possible when the RDP is
+                * changing to level 0 (from level 1 to level 0 or from level 0.5 to level 0). */
+               if (stm32l4_info->rdp != RDP_LEVEL_1 && stm32l4_info->rdp != RDP_LEVEL_0_5) {
+                       LOG_ERROR("Deactivation of TZEN is only possible when the RDP is changing to level 0");
+                       return ERROR_FAIL;
+               }
+
+               retval = stm32l4_write_option(bank, stm32l4_info->flash_regs[STM32_FLASH_OPTR_INDEX],
+                               RDP_LEVEL_0, FLASH_RDP_MASK | FLASH_TZEN);
+       }
+
        if (retval != ERROR_OK)
                return retval;
 
-       /* Set OBL_LAUNCH bit in CR -> system reset and option bytes reload,
-        * but the RMs explicitly do *NOT* list this as power-on reset cause, and:
-        * "Note: If the read protection is set while the debugger is still
-        * connected through JTAG/SWD, apply a POR (power-on reset) instead of a system reset."
-        */
-       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_OBL_LAUNCH);
+       return stm32l4_perform_obl_launch(bank);
+}
 
-       command_print(CMD, "stm32l4x option load completed. Power-on reset might be required");
+COMMAND_HANDLER(stm32l4_handle_option_load_command)
+{
+       if (CMD_ARGC != 1)
+               return ERROR_COMMAND_SYNTAX_ERROR;
 
-       /* Need to re-probe after change */
-       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
-       stm32l4_info->probed = false;
+       struct flash_bank *bank;
+       int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
+       if (retval != ERROR_OK)
+               return retval;
 
-       return retval;
+       retval = stm32l4_perform_obl_launch(bank);
+       if (retval != ERROR_OK) {
+               command_print(CMD, "stm32l4x option load failed");
+               return retval;
+       }
+
+
+       command_print(CMD, "stm32l4x option load completed. Power-on reset might be required");
+
+       return ERROR_OK;
 }
 
 COMMAND_HANDLER(stm32l4_handle_lock_command)
@@ -2013,6 +2099,13 @@ static const struct command_registration stm32l4_exec_command_handlers[] = {
                .usage = "bank_id reg_offset value mask",
                .help = "Write device option bit fields with provided value.",
        },
+       {
+               .name = "trustzone",
+               .handler = stm32l4_handle_trustzone_command,
+               .mode = COMMAND_EXEC,
+               .usage = "<bank_id> [enable|disable]",
+               .help = "Configure TrustZone security",
+       },
        {
                .name = "wrp_info",
                .handler = stm32l4_handle_wrp_info_command,