cr50: add rollback information to the sysinfo command output

With enabling INFO1 map based rollback protection it is important to
be able to tell the state of the flash map and the currently installed
images' infomap header field.

The new function counts number of zero words in the info map and zero
bits in both RW headers, and returns them in a string printed out by
the sysinfo command.

BRANCH=cr50
BUG=b:35774863
TEST=built images with different manifest info field contents and
     verified that the string printed by the sysinfo command makes sense.

Change-Id: If633a6c678dc34197b2dad116b6180b2d549e089
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/450905
Reviewed-by: Nagendra Modadugu <ngm@google.com>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>
(cherry picked from commit 855ac132242cab78197463bdd7d11fa57c108d9a)
Reviewed-on: https://chromium-review.googlesource.com/452552

3 files changed, 55 insertions, 0 deletions

diff --git a/board/cr50/board.c b/board/cr50/board.c
index 8faf81bb55..ade07be2a5 100644
--- a/board/cr50/board.c
+++ b/board/cr50/board.c
@@ -1293,6 +1293,7 @@ static int command_sysinfo(int argc, char **argv)
 	uintptr_t vaddr;
 	const struct SignedHeader *h;
 	int reset_count = GREG32(PMU, LONG_LIFE_SCRATCH0);
+	char rollback_str[15];
 
 	ccprintf("Reset flags: 0x%08x (", system_get_reset_flags());
 	system_print_reset_flags();
@@ -1317,6 +1318,9 @@ static int command_sysinfo(int argc, char **argv)
 	ccprintf("DEV_ID:      0x%08x 0x%08x\n",
 		 GREG32(FUSE, DEV_ID0), GREG32(FUSE, DEV_ID1));
 
+	system_get_rollback_bits(rollback_str, sizeof(rollback_str));
+	ccprintf("Rollback:    %s\n", rollback_str);
+
 	return EC_SUCCESS;
 }
 DECLARE_SAFE_CONSOLE_COMMAND(sysinfo, command_sysinfo,
diff --git a/chip/g/system.c b/chip/g/system.c
index 5790436b2d..185f88ba99 100644
--- a/chip/g/system.c
+++ b/chip/g/system.c
@@ -621,3 +621,43 @@ void system_update_rollback_mask(void)
 	ccprintf("updated %d info map words\n", updated_words_count);
 #endif  /*  CR50_DEV ^^^^^^^^ NOT defined. */
 }
+
+void system_get_rollback_bits(char *value, size_t value_size)
+{
+	int info_count;
+	int i;
+	struct {
+		int count;
+		const struct SignedHeader *h;
+	} headers[] = {
+		{.h = (const struct SignedHeader *)
+		 get_program_memory_addr(SYSTEM_IMAGE_RW)},
+
+		{.h = (const struct SignedHeader *)
+		 get_program_memory_addr(SYSTEM_IMAGE_RW_B)},
+	};
+
+	flash_info_read_enable(INFO_RW_MAP_OFFSET, INFO_RW_MAP_SIZE);
+	for (i = 0; i < INFO_MAX; i++) {
+		uint32_t w;
+
+		flash_physical_info_read_word(INFO_RW_MAP_OFFSET +
+					      i * sizeof(uint32_t),
+					      &w);
+		if (w)
+			break;
+	}
+	info_count = i;
+
+	for (i = 0; i < ARRAY_SIZE(headers); i++) {
+		int j;
+
+		for (j = 0; j < INFO_MAX; j++)
+			if (headers[i].h->infomap[j/32] & (1 << (j%32)))
+				break;
+		headers[i].count = j;
+	}
+
+	snprintf(value, value_size, "%d/%d/%d", info_count,
+		 headers[0].count, headers[1].count);
+}
diff --git a/chip/g/system_chip.h b/chip/g/system_chip.h
index 4d6b3ec7c9..251c2d3007 100644
--- a/chip/g/system_chip.h
+++ b/chip/g/system_chip.h
@@ -57,4 +57,15 @@ int system_battery_cutoff_support_required(void);
  */
 void system_update_rollback_mask(void);
 
+/*
+ **
+ * Scan INFO1 rollback map and infomap fields of both RW and RW_B image
+ * headers, and return a string showing how many zeros are there at the base
+ * of in each of these objects.
+ *
+ * The passed in parameters are the memory area to put the string in and the
+ * size of this memory area.
+ */
+void system_get_rollback_bits(char *value, size_t value_size);
+
 #endif /* __CROS_EC_SYSTEM_CHIP_H */