mbed os with nrf51 internal bandgap enabled to read battery level

Dependents:   BLE_file_test BLE_Blink ExternalEncoder

Revision:
0:f269e3021894
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/features/mbedtls/src/havege.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,245 @@
+/**
+ *  \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+/*
+ *  The HAVEGE RNG was designed by Andre Seznec in 2002.
+ *
+ *  http://www.irisa.fr/caps/projects/hipsor/publi.php
+ *
+ *  Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_HAVEGE_C)
+
+#include "mbedtls/havege.h"
+#include "mbedtls/timing.h"
+
+#include <string.h>
+
+/* Implementation that should never be optimized out by the compiler */
+static void mbedtls_zeroize( void *v, size_t n ) {
+    volatile unsigned char *p = v; while( n-- ) *p++ = 0;
+}
+
+/* ------------------------------------------------------------------------
+ * On average, one iteration accesses two 8-word blocks in the havege WALK
+ * table, and generates 16 words in the RES array.
+ *
+ * The data read in the WALK table is updated and permuted after each use.
+ * The result of the hardware clock counter read is used  for this update.
+ *
+ * 25 conditional tests are present.  The conditional tests are grouped in
+ * two nested  groups of 12 conditional tests and 1 test that controls the
+ * permutation; on average, there should be 6 tests executed and 3 of them
+ * should be mispredicted.
+ * ------------------------------------------------------------------------
+ */
+
+#define SWAP(X,Y) { int *T = X; X = Y; Y = T; }
+
+#define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
+#define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
+
+#define TST1_LEAVE U1++; }
+#define TST2_LEAVE U2++; }
+
+#define ONE_ITERATION                                   \
+                                                        \
+    PTEST = PT1 >> 20;                                  \
+                                                        \
+    TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
+    TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
+    TST1_ENTER  TST1_ENTER  TST1_ENTER  TST1_ENTER      \
+                                                        \
+    TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
+    TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
+    TST1_LEAVE  TST1_LEAVE  TST1_LEAVE  TST1_LEAVE      \
+                                                        \
+    PTX = (PT1 >> 18) & 7;                              \
+    PT1 &= 0x1FFF;                                      \
+    PT2 &= 0x1FFF;                                      \
+    CLK = (int) mbedtls_timing_hardclock();                            \
+                                                        \
+    i = 0;                                              \
+    A = &WALK[PT1    ]; RES[i++] ^= *A;                 \
+    B = &WALK[PT2    ]; RES[i++] ^= *B;                 \
+    C = &WALK[PT1 ^ 1]; RES[i++] ^= *C;                 \
+    D = &WALK[PT2 ^ 4]; RES[i++] ^= *D;                 \
+                                                        \
+    IN = (*A >> (1)) ^ (*A << (31)) ^ CLK;              \
+    *A = (*B >> (2)) ^ (*B << (30)) ^ CLK;              \
+    *B = IN ^ U1;                                       \
+    *C = (*C >> (3)) ^ (*C << (29)) ^ CLK;              \
+    *D = (*D >> (4)) ^ (*D << (28)) ^ CLK;              \
+                                                        \
+    A = &WALK[PT1 ^ 2]; RES[i++] ^= *A;                 \
+    B = &WALK[PT2 ^ 2]; RES[i++] ^= *B;                 \
+    C = &WALK[PT1 ^ 3]; RES[i++] ^= *C;                 \
+    D = &WALK[PT2 ^ 6]; RES[i++] ^= *D;                 \
+                                                        \
+    if( PTEST & 1 ) SWAP( A, C );                       \
+                                                        \
+    IN = (*A >> (5)) ^ (*A << (27)) ^ CLK;              \
+    *A = (*B >> (6)) ^ (*B << (26)) ^ CLK;              \
+    *B = IN; CLK = (int) mbedtls_timing_hardclock();                   \
+    *C = (*C >> (7)) ^ (*C << (25)) ^ CLK;              \
+    *D = (*D >> (8)) ^ (*D << (24)) ^ CLK;              \
+                                                        \
+    A = &WALK[PT1 ^ 4];                                 \
+    B = &WALK[PT2 ^ 1];                                 \
+                                                        \
+    PTEST = PT2 >> 1;                                   \
+                                                        \
+    PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]);   \
+    PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8);  \
+    PTY = (PT2 >> 10) & 7;                              \
+                                                        \
+    TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
+    TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
+    TST2_ENTER  TST2_ENTER  TST2_ENTER  TST2_ENTER      \
+                                                        \
+    TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
+    TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
+    TST2_LEAVE  TST2_LEAVE  TST2_LEAVE  TST2_LEAVE      \
+                                                        \
+    C = &WALK[PT1 ^ 5];                                 \
+    D = &WALK[PT2 ^ 5];                                 \
+                                                        \
+    RES[i++] ^= *A;                                     \
+    RES[i++] ^= *B;                                     \
+    RES[i++] ^= *C;                                     \
+    RES[i++] ^= *D;                                     \
+                                                        \
+    IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK;             \
+    *A = (*B >> (10)) ^ (*B << (22)) ^ CLK;             \
+    *B = IN ^ U2;                                       \
+    *C = (*C >> (11)) ^ (*C << (21)) ^ CLK;             \
+    *D = (*D >> (12)) ^ (*D << (20)) ^ CLK;             \
+                                                        \
+    A = &WALK[PT1 ^ 6]; RES[i++] ^= *A;                 \
+    B = &WALK[PT2 ^ 3]; RES[i++] ^= *B;                 \
+    C = &WALK[PT1 ^ 7]; RES[i++] ^= *C;                 \
+    D = &WALK[PT2 ^ 7]; RES[i++] ^= *D;                 \
+                                                        \
+    IN = (*A >> (13)) ^ (*A << (19)) ^ CLK;             \
+    *A = (*B >> (14)) ^ (*B << (18)) ^ CLK;             \
+    *B = IN;                                            \
+    *C = (*C >> (15)) ^ (*C << (17)) ^ CLK;             \
+    *D = (*D >> (16)) ^ (*D << (16)) ^ CLK;             \
+                                                        \
+    PT1 = ( RES[( i - 8 ) ^ PTX] ^                      \
+            WALK[PT1 ^ PTX ^ 7] ) & (~1);               \
+    PT1 ^= (PT2 ^ 0x10) & 0x10;                         \
+                                                        \
+    for( n++, i = 0; i < 16; i++ )                      \
+        hs->pool[n % MBEDTLS_HAVEGE_COLLECT_SIZE] ^= RES[i];
+
+/*
+ * Entropy gathering function
+ */
+static void havege_fill( mbedtls_havege_state *hs )
+{
+    int i, n = 0;
+    int  U1,  U2, *A, *B, *C, *D;
+    int PT1, PT2, *WALK, RES[16];
+    int PTX, PTY, CLK, PTEST, IN;
+
+    WALK = hs->WALK;
+    PT1  = hs->PT1;
+    PT2  = hs->PT2;
+
+    PTX  = U1 = 0;
+    PTY  = U2 = 0;
+
+    (void)PTX;
+
+    memset( RES, 0, sizeof( RES ) );
+
+    while( n < MBEDTLS_HAVEGE_COLLECT_SIZE * 4 )
+    {
+        ONE_ITERATION
+        ONE_ITERATION
+        ONE_ITERATION
+        ONE_ITERATION
+    }
+
+    hs->PT1 = PT1;
+    hs->PT2 = PT2;
+
+    hs->offset[0] = 0;
+    hs->offset[1] = MBEDTLS_HAVEGE_COLLECT_SIZE / 2;
+}
+
+/*
+ * HAVEGE initialization
+ */
+void mbedtls_havege_init( mbedtls_havege_state *hs )
+{
+    memset( hs, 0, sizeof( mbedtls_havege_state ) );
+
+    havege_fill( hs );
+}
+
+void mbedtls_havege_free( mbedtls_havege_state *hs )
+{
+    if( hs == NULL )
+        return;
+
+    mbedtls_zeroize( hs, sizeof( mbedtls_havege_state ) );
+}
+
+/*
+ * HAVEGE rand function
+ */
+int mbedtls_havege_random( void *p_rng, unsigned char *buf, size_t len )
+{
+    int val;
+    size_t use_len;
+    mbedtls_havege_state *hs = (mbedtls_havege_state *) p_rng;
+    unsigned char *p = buf;
+
+    while( len > 0 )
+    {
+        use_len = len;
+        if( use_len > sizeof(int) )
+            use_len = sizeof(int);
+
+        if( hs->offset[1] >= MBEDTLS_HAVEGE_COLLECT_SIZE )
+            havege_fill( hs );
+
+        val  = hs->pool[hs->offset[0]++];
+        val ^= hs->pool[hs->offset[1]++];
+
+        memcpy( p, &val, use_len );
+
+        len -= use_len;
+        p += use_len;
+    }
+
+    return( 0 );
+}
+
+#endif /* MBEDTLS_HAVEGE_C */