From 29b0e73350073bd3f1a142d6f0e9f9f9c20ef7b0 Mon Sep 17 00:00:00 2001
From: Troels Hoffmeyer <troels.d.hoffmeyer@gmail.com>
Date: Tue, 11 Nov 2014 16:36:09 +0100
Subject: [PATCH] samr21: cpuid implemented by reading 128 bits from flash

---
 boards/samr21-xpro/Makefile.features |  2 +-
 cpu/samd21/include/cpu-conf.h        |  4 +++
 cpu/samd21/periph/cpuid.c            | 37 ++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 cpu/samd21/periph/cpuid.c

diff --git a/boards/samr21-xpro/Makefile.features b/boards/samr21-xpro/Makefile.features
index e32153a0c7..fc8df2c708 100644
--- a/boards/samr21-xpro/Makefile.features
+++ b/boards/samr21-xpro/Makefile.features
@@ -1 +1 @@
-FEATURES_PROVIDED += transceiver periph_gpio periph_spi cpp periph_timer periph_uart periph_i2c cpp periph_rtc
+FEATURES_PROVIDED += transceiver periph_gpio periph_spi cpp periph_timer periph_uart periph_i2c cpp periph_rtc periph_cpuid
diff --git a/cpu/samd21/include/cpu-conf.h b/cpu/samd21/include/cpu-conf.h
index 6868d7c470..f78e6e6c35 100644
--- a/cpu/samd21/include/cpu-conf.h
+++ b/cpu/samd21/include/cpu-conf.h
@@ -55,5 +55,9 @@ extern "C" {
 }
 #endif
 
+/**
+ * @brief CPUID_ID_LEN length of cpuid in bytes
+ */
+#define CPUID_ID_LEN (16) /* 128 bits long, 16 bytes long */
 #endif /* __CPU_CONF_H */
 /** @} */
diff --git a/cpu/samd21/periph/cpuid.c b/cpu/samd21/periph/cpuid.c
new file mode 100644
index 0000000000..c32ea92623
--- /dev/null
+++ b/cpu/samd21/periph/cpuid.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @addtogroup  driver_periph
+ * @{
+ *
+ * @file        cpuid.c
+ * @brief       Low-level CPUID driver implementation
+ *
+ * @author      Troels Hoffmeyer <troels.d.hoffmeyer@gmail.com>
+ */
+
+#include <string.h>
+
+#include "cpu-conf.h"
+#include "periph/cpuid.h"
+
+#define SAMD21_CPUID_WORD0 (*(volatile uint32_t *)0x0080A00C)
+#define SAMD21_CPUID_WORD1 (*(volatile uint32_t *)0x0080A040)
+#define SAMD21_CPUID_WORD2 (*(volatile uint32_t *)0x0080A044)
+#define SAMD21_CPUID_WORD3 (*(volatile uint32_t *)0x0080A048)
+
+
+void cpuid_get(void *id)
+{
+    uint32_t source_address[] = { SAMD21_CPUID_WORD0,
+                                  SAMD21_CPUID_WORD1,
+                                  SAMD21_CPUID_WORD2,
+                                  SAMD21_CPUID_WORD3};
+    memcpy(id, (void*) source_address, CPUID_ID_LEN);
+}