Chrome EC

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Chrome EC

The Chrome EC is used in almost all Chrome OS devices, and an increasing number of accessories, like Google's Type C chargers. It is based on the Chromium EC code base.

Building the Chrome EC

Building in the ChromiumOS environment

Getting started building EC images quickly

Building outside of the ChromiumOS chroot

Build requirements

You will need:

  • GNU Make 4.1 (older versions are having trouble with the Makefiles)
  • an ARM cross compiler (I used coreboot's armv7-a-eabi- toolchain)

Patches required

Patching up the code:

diff --git a/Makefile.toolchain b/Makefile.toolchain
index f015726..759dfb0 100644
--- a/Makefile.toolchain
+++ b/Makefile.toolchain
 CFLAGS+= -ffunction-sections -fshort-wchar
 CFLAGS+= -fno-delete-null-pointer-checks -fconserve-stack
+CFLAGS+= -ffreestanding
+CPPFLAGS+= -ffreestanding
 FTDIVERSION=$(shell $(PKG_CONFIG) --modversion libftdi1 2>/dev/null)
 ifneq ($(FTDIVERSION),)


diff --git a/include/timer.h b/include/timer.h
index 5f92207..1a43604 100644
--- a/include/timer.h
+++ b/include/timer.h
@@ -8,7 +8,7 @@
 #ifndef __CROS_EC_TIMER_H
 #define __CROS_EC_TIMER_H
-#include <sys/types.h>
+typedef long clock_t;
 #include "common.h"
 #include "task_id.h"


diff --git a/driver/pi3usb30532.h b/driver/pi3usb30532.h
index 96c9632..15a9241 100644
--- a/driver/pi3usb30532.h
+++ b/driver/pi3usb30532.h
@@ -8,8 +8,6 @@
 #ifndef __CROS_EC_PI3USB30532_H
 #define __CROS_EC_PI3USB30532_H
-#include <inttypes.h>
 #include "usb_pd.h"
 /* USB switch registers */


diff --git a/driver/als_si114x.c b/driver/als_si114x.c
index bdd39fa..5a64be9 100644
--- a/driver/als_si114x.c
+++ b/driver/als_si114x.c
@@ -219,7 +219,7 @@ static int irq_handler(struct motion_sensor_t *s, uint32_t *event)
 /* Just trigger a measurement */
 static int read(const struct motion_sensor_t *s, vector_3_t v)
-       int ret;
+       int ret = 0;
        uint8_t cmd;
        struct si114x_drv_data_t *data = SI114X_GET_DATA(s);

Build instructions

Let's go:

$ sudo aptitude install libftdi-dev
$ git clone
$ cd vboot_reference
$ make
$ cp build/futility/futility ~/bin
$ cd ..
$ git clone
$ cd ec
$ CROSS_COMPILE=armv7-a-eabi- HOST_CROSS_COMPILE= make BOARD=chell


Targets not building

  • cr50 (make issue with -C)
  • glados,kunimitsu,wheatley: `memset' referenced in section `.text' of /tmp/cc3Dv6dh.ltrans2.ltrans.o: defined in discarded section `.text' of build/wheatley/RO/common/util.o (symbol from plugin)
  • it8380dev: armv7-a-eabi-gcc: error: unrecognized argument in option '-march=v3m'
  • Not real targets, but in board/: host, OWNERS