cr50: complete support of the new NVMEM structure

This patch eliminates unnecessary legacy nvmem.c and nvmem_vars.c code
and brings the code base to the state where the new NVMEM layout is
fully functional.

BRANCH=cr50, cr50-mp
BUG=b:69907320, b:129710256
CQ-DEPEND=CL:1450278
TEST=the following tests pass:
   - test cases in ./test/nvmem.c

   - TCG suite (passes on par with the existing Cr50 code with the
     reduced code footprint TPM2 library)

   - Chrome OS device migrates from legacy to new implementation with
     user account maintained.

   - Chrome OS user account is maintained over AP and H1 reboots and
     deep sleep cycles.

Change-Id: If4bc2dd125873a79dbe0e268eb32100a8b8b352d
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1496607
Reviewed-by: Andrey Pronin <apronin@chromium.org>

3 files changed, 18 insertions, 15 deletions

diff --git a/board/cr50/board.c b/board/cr50/board.c
index 09a43901a4..e7482a9577 100644
--- a/board/cr50/board.c
+++ b/board/cr50/board.c
@@ -717,8 +717,6 @@ static void board_init(void)
 	init_runlevel(PERMISSION_MEDIUM);
 	/* Initialize NvMem partitions */
 	nvmem_init();
-	/* Initialize the persistent storage. */
-	initvars();
 
 	/*
 	 * If this was a low power wake and not a rollback, restore the ccd
diff --git a/board/cr50/board.h b/board/cr50/board.h
index 2e75645138..f6f2f5c9de 100644
--- a/board/cr50/board.h
+++ b/board/cr50/board.h
@@ -62,12 +62,20 @@
 #define CONFIG_FLASH_NVMEM_OFFSET_A (CFG_TOP_A_OFF + CONFIG_FLASH_NVCTR_SIZE)
 #define CONFIG_FLASH_NVMEM_OFFSET_B (CFG_TOP_B_OFF + CONFIG_FLASH_NVCTR_SIZE)
 /* Address of start of Nvmem area */
-#define CONFIG_FLASH_NVMEM_BASE_A (CONFIG_PROGRAM_MEMORY_BASE + \
-				 CONFIG_FLASH_NVMEM_OFFSET_A)
-#define CONFIG_FLASH_NVMEM_BASE_B (CONFIG_PROGRAM_MEMORY_BASE + \
-				 CONFIG_FLASH_NVMEM_OFFSET_B)
+#define CONFIG_FLASH_NVMEM_BASE_A                                              \
+	(CONFIG_PROGRAM_MEMORY_BASE + CONFIG_FLASH_NVMEM_OFFSET_A)
+#define CONFIG_FLASH_NVMEM_BASE_B                                              \
+	(CONFIG_PROGRAM_MEMORY_BASE + CONFIG_FLASH_NVMEM_OFFSET_B)
+#define CONFIG_FLASH_NEW_NVMEM_BASE_A                                          \
+	(CONFIG_FLASH_NVMEM_BASE_A + CONFIG_FLASH_BANK_SIZE)
+#define CONFIG_FLASH_NEW_NVMEM_BASE_B                                          \
+	(CONFIG_FLASH_NVMEM_BASE_B + CONFIG_FLASH_BANK_SIZE)
+
 /* Size partition in NvMem */
 #define NVMEM_PARTITION_SIZE (CFG_TOP_SIZE - CONFIG_FLASH_NVCTR_SIZE)
+#define NEW_NVMEM_PARTITION_SIZE (NVMEM_PARTITION_SIZE - CONFIG_FLASH_BANK_SIZE)
+#define NEW_NVMEM_TOTAL_PAGES                                                  \
+	(2 * NEW_NVMEM_PARTITION_SIZE / CONFIG_FLASH_BANK_SIZE)
 /* Size in bytes of NvMem area */
 #define CONFIG_FLASH_LOG
 #define CONFIG_FLASH_NVMEM_SIZE (NVMEM_PARTITION_SIZE * NVMEM_NUM_PARTITIONS)
diff --git a/board/cr50/u2f.c b/board/cr50/u2f.c
index a858edfa58..320f026a6e 100644
--- a/board/cr50/u2f.c
+++ b/board/cr50/u2f.c
@@ -82,25 +82,22 @@ static int load_state(void)
 		/* create random salt */
 		if (!DCRYPTO_ladder_random(salt))
 			return 0;
-		if (setvar(&k_salt, sizeof(k_salt),
-			   (const uint8_t *)salt, sizeof(salt)))
+		if (setvar(&k_salt, sizeof(k_salt), (const uint8_t *)salt,
+			   sizeof(salt)))
 			return 0;
-		/* really save the new variable to flash */
-		writevars();
 	} else {
 		memcpy(salt, tuple_val(t_salt), sizeof(salt));
+		freevar(t_salt);
 	}
 
-	if (read_tpm_nvmem_hidden(
-		TPM_HIDDEN_U2F_KEK,
-		sizeof(salt_kek), salt_kek) ==
-	    tpm_read_not_found) {
+	if (read_tpm_nvmem_hidden(TPM_HIDDEN_U2F_KEK, sizeof(salt_kek),
+				  salt_kek) == tpm_read_not_found) {
 		/*
 		 * Not found means that we have not used u2f before,
 		 * or not used it with updated fw that resets kek seed
 		 * on TPM clear.
 		 */
-		if (t_salt) {
+		if (t_salt) { /* Note that memory has been freed already!. */
 			/*
 			 * We have previously used u2f, and may have
 			 * existing registrations; we don't want to