clk: stm32mp1: add function to control MCU subsystem

Add a new function to control the MCU subsystem
security state.

Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Change-Id: I070eec06fc93a1214227f25a6a4f1c40c66c86b0
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/188430


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: Gabriel FERNANDEZ <gabriel.fernandez@st.com>
Reviewed-by: Etienne CARRIERE <etienne.carriere@st.com>
Reviewed-by: Yann GAUTIER <yann.gautier@st.com>

drivers/st/clk/stm32mp1_clk.c

@@ -3368,6 +3368,17 @@ int stm32mp1_clock_stopmode_resume(void)
 	return 0;
 }
 
+void stm32mp1_clk_mcuss_protect(bool enable)
+{
+	uintptr_t rcc_base = stm32mp_rcc_base();
+
+	if (enable) {
+		mmio_setbits_32(rcc_base + RCC_TZCR, RCC_TZCR_MCKPROT);
+	} else {
+		mmio_clrbits_32(rcc_base + RCC_TZCR, RCC_TZCR_MCKPROT);
+	}
+}
+
 /* Sync secure clock refcount after all drivers probe/inits,  */
 void stm32mp1_dump_clocks_state(void)
 {

include/drivers/st/stm32mp1_clk.h

 /*
- * Copyright (c) 2018-2019, STMicroelectronics - All Rights Reserved
+ * Copyright (c) 2018-2020, STMicroelectronics - All Rights Reserved
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -57,6 +57,8 @@ int stm32mp1_clock_stopmode_resume(void);
 void restore_clock_pm_context(void);
 void save_clock_pm_context(void);
 
+void stm32mp1_clk_mcuss_protect(bool enable);
+
 void stm32mp1_dump_clocks_state(void);
 
 #ifdef STM32MP_SHARED_RESOURCES