From 9fafc4575e17ddc761325bf918ace7b379ae56bd 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            | 17 +++++++++++++++++
 3 files changed, 22 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 1a729a107bbf9..06c585d67d392 100644
--- a/boards/samr21-xpro/Makefile.features
+++ b/boards/samr21-xpro/Makefile.features
@@ -1 +1 @@
-FEATURES_PROVIDED += periph_gpio cpp
+FEATURES_PROVIDED += periph_gpio periph_cpuid cpp
diff --git a/cpu/samd21/include/cpu-conf.h b/cpu/samd21/include/cpu-conf.h
index b2dd64aee55e0..9b3f1afb8dfa3 100644
--- a/cpu/samd21/include/cpu-conf.h
+++ b/cpu/samd21/include/cpu-conf.h
@@ -48,5 +48,9 @@
 /** @} */
 
 
+/**
+ * @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 0000000000000..6673dc4f2c37a
--- /dev/null
+++ b/cpu/samd21/periph/cpuid.c
@@ -0,0 +1,17 @@
+
+#include <string.h>
+
+#include "cpu-conf.h"
+#include "periph/cpuid.h"
+
+#define Word0 (*(volatile uint32_t *)0x0080A00C)
+#define Word1 (*(volatile uint32_t *)0x0080A040)
+#define Word2 (*(volatile uint32_t *)0x0080A044)
+#define Word3 (*(volatile uint32_t *)0x0080A048)
+
+
+void cpuid_get(void *id)
+{
+    uint32_t source_address[] = {Word0, Word1, Word2, Word3};
+    memcpy(id, (void*) source_address, CPUID_ID_LEN);
+}