atsha204a-i2c.c 11 KB

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  1. /*
  2. * I2C Driver for Atmel ATSHA204 over I2C
  3. *
  4. * Copyright (C) 2014 Josh Datko, Cryptotronix, jbd@cryptotronix.com
  5. * 2016 Tomas Hlavacek, CZ.NIC, tmshlvck@gmail.com
  6. * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
  7. *
  8. * This program is free software; you can redistribute it and/or modify it
  9. * under the terms of the GNU General Public License version 2 as
  10. * published by the Free Software Foundation.
  11. */
  12. #include <common.h>
  13. #include <dm.h>
  14. #include <i2c.h>
  15. #include <errno.h>
  16. #include <atsha204a-i2c.h>
  17. #include <log.h>
  18. #include <asm/global_data.h>
  19. #include <linux/delay.h>
  20. #include <u-boot/crc.h>
  21. #define ATSHA204A_TWLO 60
  22. #define ATSHA204A_TRANSACTION_TIMEOUT 100000
  23. #define ATSHA204A_TRANSACTION_RETRY 5
  24. #define ATSHA204A_EXECTIME 5000
  25. DECLARE_GLOBAL_DATA_PTR;
  26. /*
  27. * The ATSHA204A uses an (to me) unknown CRC-16 algorithm.
  28. * The Reveng CRC-16 catalogue does not contain it.
  29. *
  30. * Because in Atmel's documentation only a primitive implementation
  31. * can be found, I have implemented this one with lookup table.
  32. */
  33. /*
  34. * This is the code that computes the table below:
  35. *
  36. * int i, j;
  37. * for (i = 0; i < 256; ++i) {
  38. * u8 c = 0;
  39. * for (j = 0; j < 8; ++j) {
  40. * c = (c << 1) | ((i >> j) & 1);
  41. * }
  42. * bitreverse_table[i] = c;
  43. * }
  44. */
  45. static u8 const bitreverse_table[256] = {
  46. 0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
  47. 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
  48. 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
  49. 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
  50. 0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
  51. 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
  52. 0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
  53. 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
  54. 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
  55. 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
  56. 0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
  57. 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
  58. 0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
  59. 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
  60. 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
  61. 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
  62. 0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
  63. 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
  64. 0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
  65. 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
  66. 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
  67. 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
  68. 0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
  69. 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
  70. 0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
  71. 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
  72. 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
  73. 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
  74. 0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
  75. 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
  76. 0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
  77. 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
  78. };
  79. /*
  80. * This is the code that computes the table below:
  81. *
  82. * int i, j;
  83. * for (i = 0; i < 256; ++i) {
  84. * u16 c = i << 8;
  85. * for (j = 0; j < 8; ++j) {
  86. * int b = c >> 15;
  87. * c <<= 1;
  88. * if (b)
  89. * c ^= 0x8005;
  90. * }
  91. * crc16_table[i] = c;
  92. * }
  93. */
  94. static u16 const crc16_table[256] = {
  95. 0x0000, 0x8005, 0x800f, 0x000a, 0x801b, 0x001e, 0x0014, 0x8011,
  96. 0x8033, 0x0036, 0x003c, 0x8039, 0x0028, 0x802d, 0x8027, 0x0022,
  97. 0x8063, 0x0066, 0x006c, 0x8069, 0x0078, 0x807d, 0x8077, 0x0072,
  98. 0x0050, 0x8055, 0x805f, 0x005a, 0x804b, 0x004e, 0x0044, 0x8041,
  99. 0x80c3, 0x00c6, 0x00cc, 0x80c9, 0x00d8, 0x80dd, 0x80d7, 0x00d2,
  100. 0x00f0, 0x80f5, 0x80ff, 0x00fa, 0x80eb, 0x00ee, 0x00e4, 0x80e1,
  101. 0x00a0, 0x80a5, 0x80af, 0x00aa, 0x80bb, 0x00be, 0x00b4, 0x80b1,
  102. 0x8093, 0x0096, 0x009c, 0x8099, 0x0088, 0x808d, 0x8087, 0x0082,
  103. 0x8183, 0x0186, 0x018c, 0x8189, 0x0198, 0x819d, 0x8197, 0x0192,
  104. 0x01b0, 0x81b5, 0x81bf, 0x01ba, 0x81ab, 0x01ae, 0x01a4, 0x81a1,
  105. 0x01e0, 0x81e5, 0x81ef, 0x01ea, 0x81fb, 0x01fe, 0x01f4, 0x81f1,
  106. 0x81d3, 0x01d6, 0x01dc, 0x81d9, 0x01c8, 0x81cd, 0x81c7, 0x01c2,
  107. 0x0140, 0x8145, 0x814f, 0x014a, 0x815b, 0x015e, 0x0154, 0x8151,
  108. 0x8173, 0x0176, 0x017c, 0x8179, 0x0168, 0x816d, 0x8167, 0x0162,
  109. 0x8123, 0x0126, 0x012c, 0x8129, 0x0138, 0x813d, 0x8137, 0x0132,
  110. 0x0110, 0x8115, 0x811f, 0x011a, 0x810b, 0x010e, 0x0104, 0x8101,
  111. 0x8303, 0x0306, 0x030c, 0x8309, 0x0318, 0x831d, 0x8317, 0x0312,
  112. 0x0330, 0x8335, 0x833f, 0x033a, 0x832b, 0x032e, 0x0324, 0x8321,
  113. 0x0360, 0x8365, 0x836f, 0x036a, 0x837b, 0x037e, 0x0374, 0x8371,
  114. 0x8353, 0x0356, 0x035c, 0x8359, 0x0348, 0x834d, 0x8347, 0x0342,
  115. 0x03c0, 0x83c5, 0x83cf, 0x03ca, 0x83db, 0x03de, 0x03d4, 0x83d1,
  116. 0x83f3, 0x03f6, 0x03fc, 0x83f9, 0x03e8, 0x83ed, 0x83e7, 0x03e2,
  117. 0x83a3, 0x03a6, 0x03ac, 0x83a9, 0x03b8, 0x83bd, 0x83b7, 0x03b2,
  118. 0x0390, 0x8395, 0x839f, 0x039a, 0x838b, 0x038e, 0x0384, 0x8381,
  119. 0x0280, 0x8285, 0x828f, 0x028a, 0x829b, 0x029e, 0x0294, 0x8291,
  120. 0x82b3, 0x02b6, 0x02bc, 0x82b9, 0x02a8, 0x82ad, 0x82a7, 0x02a2,
  121. 0x82e3, 0x02e6, 0x02ec, 0x82e9, 0x02f8, 0x82fd, 0x82f7, 0x02f2,
  122. 0x02d0, 0x82d5, 0x82df, 0x02da, 0x82cb, 0x02ce, 0x02c4, 0x82c1,
  123. 0x8243, 0x0246, 0x024c, 0x8249, 0x0258, 0x825d, 0x8257, 0x0252,
  124. 0x0270, 0x8275, 0x827f, 0x027a, 0x826b, 0x026e, 0x0264, 0x8261,
  125. 0x0220, 0x8225, 0x822f, 0x022a, 0x823b, 0x023e, 0x0234, 0x8231,
  126. 0x8213, 0x0216, 0x021c, 0x8219, 0x0208, 0x820d, 0x8207, 0x0202,
  127. };
  128. static inline u16 crc16_byte(u16 crc, const u8 data)
  129. {
  130. u16 t = crc16_table[((crc >> 8) ^ bitreverse_table[data]) & 0xff];
  131. return ((crc << 8) ^ t);
  132. }
  133. static u16 atsha204a_crc16(const u8 *buffer, size_t len)
  134. {
  135. u16 crc = 0;
  136. while (len--)
  137. crc = crc16_byte(crc, *buffer++);
  138. return cpu_to_le16(crc);
  139. }
  140. static int atsha204a_send(struct udevice *dev, const u8 *buf, u8 len)
  141. {
  142. fdt_addr_t *priv = dev_get_priv(dev);
  143. struct i2c_msg msg;
  144. msg.addr = *priv;
  145. msg.flags = I2C_M_STOP;
  146. msg.len = len;
  147. msg.buf = (u8 *) buf;
  148. return dm_i2c_xfer(dev, &msg, 1);
  149. }
  150. static int atsha204a_recv(struct udevice *dev, u8 *buf, u8 len)
  151. {
  152. fdt_addr_t *priv = dev_get_priv(dev);
  153. struct i2c_msg msg;
  154. msg.addr = *priv;
  155. msg.flags = I2C_M_RD | I2C_M_STOP;
  156. msg.len = len;
  157. msg.buf = (u8 *) buf;
  158. return dm_i2c_xfer(dev, &msg, 1);
  159. }
  160. static int atsha204a_recv_resp(struct udevice *dev,
  161. struct atsha204a_resp *resp)
  162. {
  163. int res;
  164. u16 resp_crc, computed_crc;
  165. u8 *p = (u8 *) resp;
  166. res = atsha204a_recv(dev, p, 4);
  167. if (res)
  168. return res;
  169. if (resp->length > 4) {
  170. if (resp->length > sizeof(*resp))
  171. return -EMSGSIZE;
  172. res = atsha204a_recv(dev, p + 4, resp->length - 4);
  173. if (res)
  174. return res;
  175. }
  176. resp_crc = (u16) p[resp->length - 2]
  177. | (((u16) p[resp->length - 1]) << 8);
  178. computed_crc = atsha204a_crc16(p, resp->length - 2);
  179. if (resp_crc != computed_crc) {
  180. debug("Invalid checksum in ATSHA204A response\n");
  181. return -EBADMSG;
  182. }
  183. return 0;
  184. }
  185. int atsha204a_wakeup(struct udevice *dev)
  186. {
  187. u8 req[4];
  188. struct atsha204a_resp resp;
  189. int try, res;
  190. debug("Waking up ATSHA204A\n");
  191. for (try = 1; try <= 10; ++try) {
  192. debug("Try %i... ", try);
  193. memset(req, 0, 4);
  194. res = atsha204a_send(dev, req, 4);
  195. if (res) {
  196. debug("failed on I2C send, trying again\n");
  197. continue;
  198. }
  199. udelay(ATSHA204A_TWLO);
  200. res = atsha204a_recv_resp(dev, &resp);
  201. if (res) {
  202. debug("failed on receiving response, ending\n");
  203. return res;
  204. }
  205. if (resp.code != ATSHA204A_STATUS_AFTER_WAKE) {
  206. debug ("failed (responce code = %02x), ending\n",
  207. resp.code);
  208. return -EBADMSG;
  209. }
  210. debug("success\n");
  211. break;
  212. }
  213. return 0;
  214. }
  215. int atsha204a_idle(struct udevice *dev)
  216. {
  217. int res;
  218. u8 req = ATSHA204A_FUNC_IDLE;
  219. res = atsha204a_send(dev, &req, 1);
  220. if (res)
  221. debug("Failed putting ATSHA204A idle\n");
  222. return res;
  223. }
  224. int atsha204a_sleep(struct udevice *dev)
  225. {
  226. int res;
  227. u8 req = ATSHA204A_FUNC_IDLE;
  228. res = atsha204a_send(dev, &req, 1);
  229. if (res)
  230. debug("Failed putting ATSHA204A to sleep\n");
  231. return res;
  232. }
  233. static int atsha204a_transaction(struct udevice *dev, struct atsha204a_req *req,
  234. struct atsha204a_resp *resp)
  235. {
  236. int res, timeout = ATSHA204A_TRANSACTION_TIMEOUT;
  237. res = atsha204a_send(dev, (u8 *) req, req->length + 1);
  238. if (res) {
  239. debug("ATSHA204A transaction send failed\n");
  240. return -EBUSY;
  241. }
  242. do {
  243. res = atsha204a_recv_resp(dev, resp);
  244. if (!res || res == -EMSGSIZE || res == -EBADMSG)
  245. break;
  246. debug("ATSHA204A transaction polling for response "
  247. "(timeout = %d)\n", timeout);
  248. udelay(ATSHA204A_EXECTIME);
  249. timeout -= ATSHA204A_EXECTIME;
  250. } while (timeout > 0);
  251. if (timeout <= 0) {
  252. debug("ATSHA204A transaction timed out\n");
  253. return -ETIMEDOUT;
  254. }
  255. return res;
  256. }
  257. static void atsha204a_req_crc32(struct atsha204a_req *req)
  258. {
  259. u8 *p = (u8 *) req;
  260. u16 computed_crc;
  261. u16 *crc_ptr = (u16 *) &p[req->length - 1];
  262. /* The buffer to crc16 starts at byte 1, not 0 */
  263. computed_crc = atsha204a_crc16(p + 1, req->length - 2);
  264. *crc_ptr = cpu_to_le16(computed_crc);
  265. }
  266. int atsha204a_read(struct udevice *dev, enum atsha204a_zone zone, bool read32,
  267. u16 addr, u8 *buffer)
  268. {
  269. int res, retry = ATSHA204A_TRANSACTION_RETRY;
  270. struct atsha204a_req req;
  271. struct atsha204a_resp resp;
  272. req.function = ATSHA204A_FUNC_COMMAND;
  273. req.length = 7;
  274. req.command = ATSHA204A_CMD_READ;
  275. req.param1 = (u8) zone;
  276. if (read32)
  277. req.param1 |= 0x80;
  278. req.param2 = cpu_to_le16(addr);
  279. atsha204a_req_crc32(&req);
  280. do {
  281. res = atsha204a_transaction(dev, &req, &resp);
  282. if (!res)
  283. break;
  284. debug("ATSHA204A read retry (%d)\n", retry);
  285. retry--;
  286. atsha204a_wakeup(dev);
  287. } while (retry >= 0);
  288. if (res) {
  289. debug("ATSHA204A read failed\n");
  290. return res;
  291. }
  292. if (resp.length != (read32 ? 32 : 4) + 3) {
  293. debug("ATSHA204A read bad response length (%d)\n",
  294. resp.length);
  295. return -EBADMSG;
  296. }
  297. memcpy(buffer, ((u8 *) &resp) + 1, read32 ? 32 : 4);
  298. return 0;
  299. }
  300. int atsha204a_get_random(struct udevice *dev, u8 *buffer, size_t max)
  301. {
  302. int res;
  303. struct atsha204a_req req;
  304. struct atsha204a_resp resp;
  305. req.function = ATSHA204A_FUNC_COMMAND;
  306. req.length = 7;
  307. req.command = ATSHA204A_CMD_RANDOM;
  308. req.param1 = 1;
  309. req.param2 = 0;
  310. /* We do not have to compute the checksum dynamically */
  311. req.data[0] = 0x27;
  312. req.data[1] = 0x47;
  313. res = atsha204a_transaction(dev, &req, &resp);
  314. if (res) {
  315. debug("ATSHA204A random transaction failed\n");
  316. return res;
  317. }
  318. memcpy(buffer, ((u8 *) &resp) + 1, max >= 32 ? 32 : max);
  319. return 0;
  320. }
  321. static int atsha204a_of_to_plat(struct udevice *dev)
  322. {
  323. fdt_addr_t *priv = dev_get_priv(dev);
  324. fdt_addr_t addr;
  325. addr = fdtdec_get_addr(gd->fdt_blob, dev_of_offset(dev), "reg");
  326. if (addr == FDT_ADDR_T_NONE) {
  327. debug("Can't get ATSHA204A I2C base address\n");
  328. return -ENXIO;
  329. }
  330. *priv = addr;
  331. return 0;
  332. }
  333. static const struct udevice_id atsha204a_ids[] = {
  334. { .compatible = "atmel,atsha204a" },
  335. { }
  336. };
  337. U_BOOT_DRIVER(atsha204) = {
  338. .name = "atsha204",
  339. .id = UCLASS_MISC,
  340. .of_match = atsha204a_ids,
  341. .of_to_plat = atsha204a_of_to_plat,
  342. .priv_auto = sizeof(fdt_addr_t),
  343. };