stm32: Add helper function for H7 flash ctrl regs

Add helper function definitions for H7 to API added in chromium:2220735.
This should enable flash_physical test to run on Dartmonkey.

Refactor code to pull flash registers function declarations from
flash-reg.h instead of flash-f.h

BRANCH=None
BUG=b:157692395
TEST=On dartmonkey
	./test/run_device_tests.py -t flash_physical
       	=> pass

Signed-off-by: Josie Nordrum <josienordrum@google.com>
Change-Id: I76846938748cbe77d534915856af0ebb7211d247
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2576799
Reviewed-by: Tom Hughes <tomhughes@chromium.org>

4 files changed, 199 insertions, 105 deletions

diff --git a/chip/stm32/flash-f.h b/chip/stm32/flash-f.h
index 8d2b8e1fae..cbbe6ec86f 100644
--- a/chip/stm32/flash-f.h
+++ b/chip/stm32/flash-f.h
@@ -23,94 +23,4 @@ enum flash_rdp_level {
 
 bool is_flash_rdp_enabled(void);
 
-/**
- * Unlock the flash control register using the unlock sequence.
- *
- * If the flash control register has been disabled since the last reset when
- * this function is called, a bus fault will be generated.
- *
- * See "3.5.1 Unlocking the Flash control register" in RM0402.
- */
-void unlock_flash_control_register(void);
-
-/**
- * Unlock the flash option bytes register using the unlock sequence.
- *
- * If the flash option bytes register has been disabled since the last reset
- * when this function is called, a bus fault will be generated.
- *
- * See "3.6.2 Programming user option bytes" in RM0402.
- */
-void unlock_flash_option_bytes(void);
-
-/**
- * Lock the flash control register.
- *
- * If the flash control register has been disabled since the last reset when
- * this function is called, a bus fault will be generated.
- *
- * See "3.5.1 Unlocking the Flash control register" in RM0402.
- */
-void lock_flash_control_register(void);
-
-/**
- * Lock the flash option bytes register.
- *
- * If the flash option bytes register has been disabled since the last reset
- * when this function is called, a bus fault will be generated.
- *
- * See "3.6.2 Programming user option bytes" in RM0402.
- */
-void lock_flash_option_bytes(void);
-
-/**
- * Disable the flash option bytes register.
- *
- * This function expects that bus faults have not already been ignored when
- * called.
- *
- * Once this function is called any attempt at accessing the flash option
- * bytes register will generate a bus fault until the next reset.
- *
- * See "3.6.2 Programming user option bytes" in RM0402.
- */
-void disable_flash_option_bytes(void);
-
-/**
- * Disable the flash control register.
- *
- * This function expects that bus faults have not already been ignored when
- * called.
- *
- * Once this function is called any attempt at accessing the flash control
- * register will generate a bus fault until the next reset.
- *
- * See "3.5.1 Unlocking the Flash control register" in RM0402.
- */
-void disable_flash_control_register(void);
-
-/**
- * Check if the flash option bytes are locked.
- *
- * If the flash option bytes register has been disabled since the last reset
- * when this function is called, a bus fault will be generated.
-
- * See "3.6.2 Programming user option bytes" in RM0402.
- *
- * @return true if option bytes are locked, false otherwise
- */
-bool flash_option_bytes_locked(void);
-
-/**
- * Check if the flash control register is locked.
- *
- * If the flash control register has been disabled since the last reset
- * when this function is called, a bus fault will be generated.
- *
- * See "3.5.1 Unlocking the Flash control register" in RM0402.
- *
- * @return true if register is locked, false otherwise
- */
-bool flash_control_register_locked(void);
-
 #endif /* __CROS_EC_STM32_FLASH_F_H */
diff --git a/chip/stm32/flash-regs.h b/chip/stm32/flash-regs.h
new file mode 100644
index 0000000000..b0a46667a1
--- /dev/null
+++ b/chip/stm32/flash-regs.h
@@ -0,0 +1,109 @@
+/* Copyright 2021 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef __CROS_EC_STM32_FLASH_REGS_H
+#define __CROS_EC_STM32_FLASH_REGS_H
+
+#include <stdbool.h>
+
+/**
+ * Unlock the flash control register using the unlock sequence.
+ *
+ * If the flash control register has been disabled since the last reset when
+ * this function is called, a bus fault will be generated.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.2  FLASH key register for bank 1" in RM0433.
+ */
+void unlock_flash_control_register(void);
+
+/**
+ * Unlock the flash option bytes register using the unlock sequence.
+ *
+ * If the flash option bytes register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+ *
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.3 FLASH option key register" in RM0433.
+ */
+void unlock_flash_option_bytes(void);
+
+/**
+ * Lock the flash control register.
+ *
+ * If the flash control register has been disabled since the last reset when
+ * this function is called, a bus fault will be generated.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.4 Flash control register for bank 1" in RM0433.
+ */
+void lock_flash_control_register(void);
+
+/**
+ * Lock the flash option bytes register.
+ *
+ * If the flash option bytes register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+ *
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.7 FLASH option control register" in RM0433.
+ */
+void lock_flash_option_bytes(void);
+
+/**
+ * Disable the flash option bytes register.
+ *
+ * This function expects that bus faults have not already been ignored when
+ * called.
+ *
+ * Once this function is called any attempt at accessing the flash option
+ * bytes register will generate a bus fault until the next reset.
+ *
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.7 FLASH option control register" in RM0433.
+ */
+void disable_flash_option_bytes(void);
+
+/**
+ * Disable the flash control register.
+ *
+ * This function expects that bus faults have not already been ignored when
+ * called.
+ *
+ * Once this function is called any attempt at accessing the flash control
+ * register will generate a bus fault until the next reset.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.4 Flash control register for bank 1" in RM0433.
+ */
+void disable_flash_control_register(void);
+
+/**
+ * Check if the flash option bytes are locked.
+ *
+ * If the flash option bytes register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.7 FLASH option control register" in RM0433.
+ *
+ * @return true if option bytes are locked, false otherwise
+ */
+bool flash_option_bytes_locked(void);
+
+/**
+ * Check if the flash control register is locked.
+ *
+ * If the flash control register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.4 Flash control register for bank 1" in RM0433.
+ *
+ * @return true if register is locked, false otherwise
+ */
+bool flash_control_register_locked(void);
+
+#endif /* __CROS_EC_STM32_FLASH_REGS_H */
diff --git a/chip/stm32/flash-stm32f3.c b/chip/stm32/flash-stm32f3.c
index bae4315b67..563190b252 100644
--- a/chip/stm32/flash-stm32f3.c
+++ b/chip/stm32/flash-stm32f3.c
@@ -9,6 +9,7 @@
 #include "common.h"
 #include "flash.h"
 #include "flash-f.h"
+#include "flash-regs.h"
 #include "hooks.h"
 #include "registers.h"
 #include "system.h"
diff --git a/chip/stm32/flash-stm32h7.c b/chip/stm32/flash-stm32h7.c
index b539717158..e020e1af1d 100644
--- a/chip/stm32/flash-stm32h7.c
+++ b/chip/stm32/flash-stm32h7.c
@@ -8,6 +8,7 @@
 #include "clock.h"
 #include "cpu.h"
 #include "flash.h"
+#include "flash-regs.h"
 #include "hooks.h"
 #include "registers.h"
 #include "panic.h"
@@ -110,11 +111,7 @@ static int unlock_optb(void)
 	if (unlock(0))
 		return EC_ERROR_UNKNOWN;
 
-	/*
-	 * Always use bank 0 flash controller as there is only one option bytes
-	 * set for both banks.
-	 */
-	if (STM32_FLASH_OPTCR(0) & FLASH_OPTCR_OPTLOCK) {
+	if (flash_option_bytes_locked()) {
 		/*
 		 * We may have already locked the flash module and get a bus
 		 * fault in the attempt to unlock. Need to disable bus fault
@@ -122,13 +119,12 @@ static int unlock_optb(void)
 		 */
 		ignore_bus_fault(1);
 
-		STM32_FLASH_OPTKEYR(0) = FLASH_OPTKEYR_KEY1;
-		STM32_FLASH_OPTKEYR(0) = FLASH_OPTKEYR_KEY2;
+		unlock_flash_option_bytes();
 		ignore_bus_fault(0);
 	}
 
-	return STM32_FLASH_OPTCR(0) & FLASH_OPTCR_OPTLOCK ? EC_ERROR_UNKNOWN
-							  : EC_SUCCESS;
+	return flash_option_bytes_locked() ? EC_ERROR_UNKNOWN
+					   : EC_SUCCESS;
 }
 
 static int commit_optb(void)
@@ -142,7 +138,7 @@ static int commit_optb(void)
 	while (STM32_FLASH_OPTSR_CUR(0) & FLASH_OPTSR_BUSY && timeout-- > 0)
 		;
 
-	STM32_FLASH_OPTCR(0) |= FLASH_OPTCR_OPTLOCK;
+	lock_flash_option_bytes();
 	lock(0);
 
 	return (timeout > 0) ? EC_SUCCESS : EC_ERROR_TIMEOUT;
@@ -158,6 +154,87 @@ static void protect_blocks(uint32_t blocks)
 	commit_optb();
 }
 
+
+/*
+ * Helper function definitions for consistency with F4 to enable flash
+ * physical unitesting
+ */
+void unlock_flash_control_register(void)
+{
+	unlock(0);
+	unlock(1);
+}
+
+void unlock_flash_option_bytes(void)
+{
+	/*
+	 * Always use bank 0 flash controller as there is only one option bytes
+	 * set for both banks. See http://b/181130245
+	 *
+	 * Consecutively program values. Ref: RM0433:4.9.2
+	 */
+	STM32_FLASH_OPTKEYR(0) = FLASH_OPTKEYR_KEY1;
+	STM32_FLASH_OPTKEYR(0) = FLASH_OPTKEYR_KEY2;
+}
+
+void disable_flash_option_bytes(void)
+{
+	ignore_bus_fault(1);
+	/*
+	 * Always use bank 0 flash controller as there is only one option bytes
+	 * set for both banks. See http://b/181130245
+	 *
+	 * Writing anything other than the pre-defined keys to the option key
+	 * register results in a bus fault and the register being locked until
+	 * reboot (even with a further correct key write).
+	 */
+	STM32_FLASH_OPTKEYR(0) = 0xffffffff;
+	ignore_bus_fault(0);
+}
+
+void disable_flash_control_register(void)
+{
+	ignore_bus_fault(1);
+	/*
+	 * Writing anything other than the pre-defined keys to a key
+	 * register results in a bus fault and the register being locked until
+	 * reboot (even with a further correct key write).
+	 */
+	STM32_FLASH_KEYR(0) = 0xffffffff;
+	STM32_FLASH_KEYR(1) = 0xffffffff;
+	ignore_bus_fault(0);
+}
+
+void lock_flash_control_register(void)
+{
+	lock(0);
+	lock(1);
+}
+
+void lock_flash_option_bytes(void)
+{
+	/*
+	 * Always use bank 0 flash controller as there is only one option bytes
+	 * set for both banks. See http://b/181130245
+	 */
+	STM32_FLASH_OPTCR(0) |= FLASH_OPTCR_OPTLOCK;
+}
+
+bool flash_option_bytes_locked(void)
+{
+	/*
+	 * Always use bank 0 flash controller as there is only one option bytes
+	 * set for both banks. See http://b/181130245
+	 */
+	return  !!(STM32_FLASH_OPTCR(0) & FLASH_OPTCR_OPTLOCK);
+}
+
+bool flash_control_register_locked(void)
+{
+	return !!(STM32_FLASH_CR(0) & FLASH_CR_LOCK) &&
+	       !!(STM32_FLASH_CR(1) & FLASH_CR_LOCK);
+}
+
 /*
  * If RDP as PSTATE option is defined, use that as 'Write Protect enabled' flag:
  * it makes no sense to be able to unlock RO, as that'd allow flashing
@@ -409,18 +486,15 @@ int flash_physical_protect_now(int all)
 	 * permanently locked until reset, a correct keyring write
 	 * will not unlock it.
 	 */
-	ignore_bus_fault(1);
 
 	if (all) {
 		/* cannot do any write/erase access until next reboot */
-		STM32_FLASH_KEYR(0) = 0xffffffff;
-		STM32_FLASH_KEYR(1) = 0xffffffff;
+		disable_flash_control_register();
 		access_disabled = 1;
 	}
 	/* cannot modify the WP bits in the option bytes until reboot */
-	STM32_FLASH_OPTKEYR(0) = 0xffffffff;
+	disable_flash_option_bytes();
 	option_disabled = 1;
-	ignore_bus_fault(0);
 
 	return EC_SUCCESS;
 }