1 // Copyright (c) 2010, Atmel Corporation.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are met:
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above copyright
9 // notice, this list of conditions and the following disclaimer in the
10 // documentation and/or other materials provided with the distribution.
11 // * Neither the name of Atmel nor the
12 // names of its contributors may be used to endorse or promote products
13 // derived from this software without specific prior written permission.
14 //
15 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
16 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
19 // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
21 // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
22 // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
24 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25
26 #include <stdint.h>
27 #include "SHA_Comm.h"
28 #include "SHA_CommInterface.h"
29 #include "SHA_TimeUtils.h"
30 #include "SHA_Status.h"
31
32
33 /** \brief Calculates CRC
34 *
35 * \param[in] data pointer to data for which CRC should be calculated
36 * \param[in] count number of bytes in buffer
37 * \return
38 */
SHAC_CalculateCrc(uint8_t * data,uint8_t count)39 uint16_t SHAC_CalculateCrc(uint8_t *data, uint8_t count) {
40 uint8_t counter;
41 uint16_t crc = 0x0000;
42 uint16_t poly = 0x8005;
43 uint16_t i;
44 uint8_t nbit, cbit;
45
46 for (counter = 0; counter < count; counter++) {
47 for (i = 0x1; i < 0x100; i <<= 1) {
48 nbit = (data[counter] & (uint8_t) i) ? 1 : 0;
49 cbit = (0x8000 & crc) ? 1 : 0;
50 crc <<= 1;
51 if (nbit ^ cbit)
52 crc ^= poly;
53 }
54 }
55 #ifdef BIGENDIAN
56 crc = (crc << 8) | (crc >> 8); // flip byte order
57 #endif
58
59 return crc;
60 }
61
62
SHAC_Wakeup()63 uint8_t SHAC_Wakeup() {
64 return(SHAP_WakeDevice());
65 }
66
67
68 /** \brief Runs a communication sequence: Append CRC to tx buffer, send command, delay, receive and verify response.
69 *
70 * The first byte in tx buffer must be its byte count.
71 * If CRC or count of the response is incorrect, or a command byte got "nacked" (TWI),
72 * this function requests to re-send the response.
73 * If the response contains an error status, this function resends the command.
74 *
75 * \param[in] params pointer to parameter structure
76 * \return status of the operation
77 */
SHAC_SendAndReceive(SHA_CommParameters * params)78 int8_t SHAC_SendAndReceive(SHA_CommParameters *params) {
79 uint8_t rxSize = params->rxSize;
80 uint8_t *rxBuffer = params->rxBuffer;
81 uint8_t *txBuffer = params->txBuffer;
82 uint8_t count;
83 uint8_t countMinusCrc;
84 int8_t status;
85 uint8_t nRetries;
86 uint8_t i;
87 uint8_t statusByte;
88
89 if (!params)
90 return SHA_BAD_PARAM;
91 if (!params->txBuffer)
92 return SHA_BAD_PARAM;
93
94 count = txBuffer[SHA_BUFFER_POS_COUNT];
95 countMinusCrc = count - 2;
96 if (count < SHA_COMMAND_SIZE_MIN || rxSize < SHA_RESPONSE_SIZE_MIN || !rxBuffer)
97 return SHA_BAD_PARAM;
98
99 // Append CRC and send command.
100 *((uint16_t *) (txBuffer + countMinusCrc)) = SHAC_CalculateCrc(txBuffer, countMinusCrc);
101 status = SHAP_SendCommand(count, txBuffer);
102
103 if (status != SHA_SUCCESS) {
104 // Re-send command.
105 status = SHAP_SendCommand(count, txBuffer);
106 if (status != SHA_SUCCESS) {
107 // We lost communication. Wait until device goes to sleep.
108 //SHAP_Delay(WATCHDOG_TIMEOUT * 1000000);
109 return status;
110 }
111 }
112
113 // Wait for device to finish command execution.
114 SHAP_Delay(params->executionDelay);
115
116 // Receive response.
117 nRetries = SHA_RETRY_COUNT;
118 do {
119 // Reset response buffer.
120 for (i = 0; i < rxSize; i++)
121 rxBuffer[i] = 0;
122
123 status = SHAP_ReceiveResponse(rxSize, rxBuffer);
124 if (status != SHA_SUCCESS && !rxBuffer[SHA_BUFFER_POS_COUNT]) {
125 // We lost communication. Wait until device goes to sleep.
126 //SHAP_Delay(WATCHDOG_TIMEOUT * 1000000);
127 return status;
128 }
129
130 // Check whether we received a status packet instead of a full response.
131 if (rxSize != SHA_RESPONSE_SIZE_MIN && rxBuffer[SHA_BUFFER_POS_COUNT] == SHA_RESPONSE_SIZE_MIN) {
132 statusByte = rxBuffer[SHA_BUFFER_POS_STATUS];
133 if (statusByte == SHA_STATUS_BYTE_PARSE)
134 return SHA_PARSE_ERROR;
135 if (statusByte == SHA_STATUS_BYTE_EXEC)
136 return SHA_CMD_FAIL;
137 if (statusByte != SHA_STATUS_BYTE_COMM)
138 return SHA_STATUS_UNKNOWN;
139
140 // Communication error. Request device to re-transmit response.
141 continue;
142 }
143
144 // Received response. Verify count and CRC.
145 if (rxBuffer[SHA_BUFFER_POS_COUNT] != rxSize) {
146 status = SHA_BAD_SIZE;
147 continue;
148 }
149 countMinusCrc = rxSize - 2;
150 status = (*((uint16_t *) (rxBuffer + countMinusCrc)) == SHAC_CalculateCrc(rxBuffer, countMinusCrc))
151 ? SHA_SUCCESS : SHA_BAD_CRC;
152 } while (nRetries-- && status != SHA_SUCCESS);
153
154 return status;
155 }
156