crossystem: Add board_id property

futility is one of a few places in ChromeOS that uses "mosys platform
version".  The goal is to remove this command from mosys.

This commit adds a new property to crossystem, "board_id", which
reads the board revision from SMBIOS/FDT, and replaces the call in
futility with the appropriate VbGetSystemPropertyInt.

BUG=b:187790074
BRANCH=none
TEST="crossystem board_id" on hana and brya

Change-Id: Id69c8e309c0e509a165aa6da2778573ac7de3455
Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/4029537
Reviewed-by: Julius Werner <jwerner@chromium.org>

4 files changed, 30 insertions, 23 deletions

diff --git a/futility/updater_utils.c b/futility/updater_utils.c
index 978936fa..cc60ee8a 100644
--- a/futility/updater_utils.c
+++ b/futility/updater_utils.c
@@ -23,9 +23,6 @@
 
 #define COMMAND_BUFFER_SIZE 256
 
-/* System environment values. */
-static const char * const STR_REV = "rev";
-
 /*
  * Strips a string (usually from shell execution output) by removing all the
  * trailing characters in pattern. If pattern is NULL, match by space type
@@ -428,28 +425,9 @@ static int host_get_fw_vboot2(void)
 	return VbGetSystemPropertyInt("fw_vboot2");
 }
 
-/* A help function to get $(mosys platform version). */
 static int host_get_platform_version(void)
 {
-	char *result = host_shell("mosys platform version");
-	long rev = -1;
-
-	/* Result should be 'revN' */
-	if (strncmp(result, STR_REV, strlen(STR_REV)) == 0)
-		rev = strtol(result + strlen(STR_REV), NULL, 0);
-
-	/* we should never have negative or extremely large versions,
-	 * but clamp just to be sure
-	 */
-	if (rev < 0)
-		rev = 0;
-	if (rev > INT_MAX)
-		rev = INT_MAX;
-
-	VB2_DEBUG("Raw data = [%s], parsed version is %ld\n", result, rev);
-
-	free(result);
-	return rev;
+	return VbGetSystemPropertyInt("board_id");
 }
 
 /*
diff --git a/host/arch/arm/lib/crossystem_arch.c b/host/arch/arm/lib/crossystem_arch.c
index 79fb152e..fc54a281 100644
--- a/host/arch/arm/lib/crossystem_arch.c
+++ b/host/arch/arm/lib/crossystem_arch.c
@@ -523,6 +523,8 @@ int VbGetArchPropertyInt(const char* name)
 	} else if (!strcasecmp(name, "recoverysw_ec_boot")) {
 		/* TODO: read correct value using ectool */
 		return 0;
+	} else if (!strcasecmp(name, "board_id")) {
+		return ReadFdtInt("firmware/coreboot/board-id");
 	} else {
 		return -1;
 	}
diff --git a/host/arch/x86/lib/crossystem_arch.c b/host/arch/x86/lib/crossystem_arch.c
index e6bd7e31..f3e631ad 100644
--- a/host/arch/x86/lib/crossystem_arch.c
+++ b/host/arch/x86/lib/crossystem_arch.c
@@ -83,6 +83,10 @@
 #define GPIO_BASE_PATH "/sys/class/gpio"
 #define GPIO_EXPORT_PATH GPIO_BASE_PATH "/export"
 
+/* Base for SMBIOS information files */
+#define SMBIOS_BASE_PATH "/sys/class/dmi/id"
+#define SMBIOS_PRODUCT_VERSION_PATH SMBIOS_BASE_PATH "/product_version"
+
 /* Filename for NVRAM file */
 #define NVRAM_PATH "/dev/nvram"
 
@@ -834,6 +838,25 @@ static int ReadGpio(unsigned signal_type)
 	return (value == active_high ? 1 : 0);
 }
 
+static int GetBoardId(void)
+{
+	/*
+	 * Can't use vb2_read_file here, as it expects to be able to
+	 * seek to the end of the file to tell the size, and the sysfs
+	 * SMBIOS implementation will seek to offset 4096.
+	 */
+	int board_id = -1;
+	FILE *f = fopen(SMBIOS_PRODUCT_VERSION_PATH, "r");
+
+	if (!f)
+		return -1;
+
+	if (fscanf(f, "rev%d\n", &board_id) != 1)
+		board_id = -1;
+
+	fclose(f);
+	return board_id;
+}
 
 int VbGetArchPropertyInt(const char* name)
 {
@@ -897,6 +920,9 @@ int VbGetArchPropertyInt(const char* name)
 			value = (int)fwupdate_value;
 	}
 
+	if (!strcasecmp(name, "board_id"))
+		return GetBoardId();
+
 	return value;
 }
 
diff --git a/utility/crossystem.c b/utility/crossystem.c
index 1551209f..f5a0a133 100644
--- a/utility/crossystem.c
+++ b/utility/crossystem.c
@@ -32,6 +32,7 @@ const Param sys_param_list[] = {
   {"battery_cutoff_request", CAN_WRITE,
    "Cut off battery and shutdown on next boot"},
   {"block_devmode", CAN_WRITE, "Block all use of developer mode"},
+  {"board_id", 0, "Board hardware revision number"},
   {"clear_tpm_owner_done", CAN_WRITE, "Clear TPM owner done"},
   {"clear_tpm_owner_request", CAN_WRITE, "Clear TPM owner on next boot"},
   {"cros_debug", 0, "OS should allow debug features"},