1 files changed, 130 insertions, 1 deletions
diff --git a/chip/stm32/flash-stm32f3.c b/chip/stm32/flash-stm32f3.c
index 13dc8d8e47..299d40d5c1 120000..100644
--- a/chip/stm32/flash-stm32f3.c
+++ b/chip/stm32/flash-stm32f3.c
@@ -1 +1,130 @@
-flash-stm32f.c
-\ No newline at end of file
+/* Copyright 2014 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.
+ */
+
+/* Flash memory module for Chrome EC */
+
+#include "common.h"
+#include "flash.h"
+#include "hooks.h"
+#include "registers.h"
+#include "system.h"
+#include "panic.h"
+
+/* Flag indicating whether we have locked down entire flash */
+static int entire_flash_locked;
+
+#define FLASH_SYSJUMP_TAG 0x5750 /* "WP" - Write Protect */
+#define FLASH_HOOK_VERSION 1
+/* The previous write protect state before sys jump */
+/*
+ * TODO(crosbug.com/p/23798): check if STM32L code works here too - that is,
+ * check if entire flash is locked by attempting to lock it rather than keeping
+ * a global variable.
+ */
+struct flash_wp_state {
+	int entire_flash_locked;
+};
+
+/*****************************************************************************/
+/* Physical layer APIs */
+
+int flash_physical_get_protect(int block)
+{
+	return entire_flash_locked || !(STM32_FLASH_WRPR & (1 << block));
+}
+
+uint32_t flash_physical_get_protect_flags(void)
+{
+	uint32_t flags = 0;
+
+	/* Read all-protected state from our shadow copy */
+	if (entire_flash_locked)
+		flags |= EC_FLASH_PROTECT_ALL_NOW;
+
+	return flags;
+}
+
+int flash_physical_protect_now(int all)
+{
+	if (all) {
+		/*
+		 * Lock by writing a wrong key to FLASH_KEYR. This triggers a
+		 * bus fault, so we need to disable bus fault handler while
+		 * doing this.
+		 */
+		ignore_bus_fault(1);
+		STM32_FLASH_KEYR = 0xffffffff;
+		ignore_bus_fault(0);
+
+		entire_flash_locked = 1;
+
+		return EC_SUCCESS;
+	} else {
+		/* No way to protect just the RO flash until next boot */
+		return EC_ERROR_INVAL;
+	}
+}
+
+uint32_t flash_physical_get_valid_flags(void)
+{
+	return EC_FLASH_PROTECT_RO_AT_BOOT |
+	       EC_FLASH_PROTECT_RO_NOW |
+	       EC_FLASH_PROTECT_ALL_NOW;
+}
+
+uint32_t flash_physical_get_writable_flags(uint32_t cur_flags)
+{
+	uint32_t ret = 0;
+
+	/* If RO protection isn't enabled, its at-boot state can be changed. */
+	if (!(cur_flags & EC_FLASH_PROTECT_RO_NOW))
+		ret |= EC_FLASH_PROTECT_RO_AT_BOOT;
+
+	/*
+	 * If entire flash isn't protected at this boot, it can be enabled if
+	 * the WP GPIO is asserted.
+	 */
+	if (!(cur_flags & EC_FLASH_PROTECT_ALL_NOW) &&
+	    (cur_flags & EC_FLASH_PROTECT_GPIO_ASSERTED))
+		ret |= EC_FLASH_PROTECT_ALL_NOW;
+
+	return ret;
+}
+
+int flash_physical_restore_state(void)
+{
+	uint32_t reset_flags = system_get_reset_flags();
+	int version, size;
+	const struct flash_wp_state *prev;
+
+	/*
+	 * If we have already jumped between images, an earlier image could
+	 * have applied write protection. Nothing additional needs to be done.
+	 */
+	if (reset_flags & RESET_FLAG_SYSJUMP) {
+		prev = (const struct flash_wp_state *)system_get_jump_tag(
+				FLASH_SYSJUMP_TAG, &version, &size);
+		if (prev && version == FLASH_HOOK_VERSION &&
+		    size == sizeof(*prev))
+			entire_flash_locked = prev->entire_flash_locked;
+		return 1;
+	}
+
+	return 0;
+}
+
+/*****************************************************************************/
+/* Hooks */
+
+static void flash_preserve_state(void)
+{
+	struct flash_wp_state state;
+
+	state.entire_flash_locked = entire_flash_locked;
+
+	system_add_jump_tag(FLASH_SYSJUMP_TAG, FLASH_HOOK_VERSION,
+			    sizeof(state), &state);
+}
+DECLARE_HOOK(HOOK_SYSJUMP, flash_preserve_state, HOOK_PRIO_DEFAULT);