cros_ec_lpc.c 6.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Chromium OS cros_ec driver - LPC interface
  4. *
  5. * Copyright (c) 2012 The Chromium OS Authors.
  6. */
  7. /*
  8. * The Matrix Keyboard Protocol driver handles talking to the keyboard
  9. * controller chip. Mostly this is for keyboard functions, but some other
  10. * things have slipped in, so we provide generic services to talk to the
  11. * KBC.
  12. */
  13. #include <common.h>
  14. #include <dm.h>
  15. #include <command.h>
  16. #include <cros_ec.h>
  17. #include <log.h>
  18. #include <asm/io.h>
  19. #ifdef DEBUG_TRACE
  20. #define debug_trace(fmt, b...) debug(fmt, ##b)
  21. #else
  22. #define debug_trace(fmt, b...)
  23. #endif
  24. static int wait_for_sync(struct cros_ec_dev *dev)
  25. {
  26. unsigned long start;
  27. start = get_timer(0);
  28. while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) {
  29. if (get_timer(start) > 1000) {
  30. debug("%s: Timeout waiting for CROS_EC sync\n",
  31. __func__);
  32. return -1;
  33. }
  34. }
  35. return 0;
  36. }
  37. int cros_ec_lpc_packet(struct udevice *udev, int out_bytes, int in_bytes)
  38. {
  39. struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
  40. uint8_t *d;
  41. int i;
  42. if (out_bytes > EC_LPC_HOST_PACKET_SIZE)
  43. return log_msg_ret("Cannot send that many bytes\n", -E2BIG);
  44. if (in_bytes > EC_LPC_HOST_PACKET_SIZE)
  45. return log_msg_ret("Cannot receive that many bytes\n", -E2BIG);
  46. if (wait_for_sync(dev))
  47. return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT);
  48. /* Write data */
  49. for (i = 0, d = (uint8_t *)dev->dout; i < out_bytes; i++, d++)
  50. outb(*d, EC_LPC_ADDR_HOST_PACKET + i);
  51. /* Start the command */
  52. outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD);
  53. if (wait_for_sync(dev))
  54. return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT);
  55. /* Read back args */
  56. for (i = 0, d = dev->din; i < in_bytes; i++, d++)
  57. *d = inb(EC_LPC_ADDR_HOST_PACKET + i);
  58. return in_bytes;
  59. }
  60. int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version,
  61. const uint8_t *dout, int dout_len,
  62. uint8_t **dinp, int din_len)
  63. {
  64. struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
  65. const int cmd_addr = EC_LPC_ADDR_HOST_CMD;
  66. const int data_addr = EC_LPC_ADDR_HOST_DATA;
  67. const int args_addr = EC_LPC_ADDR_HOST_ARGS;
  68. const int param_addr = EC_LPC_ADDR_HOST_PARAM;
  69. struct ec_lpc_host_args args;
  70. uint8_t *d;
  71. int csum;
  72. int i;
  73. if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) {
  74. debug("%s: Cannot send %d bytes\n", __func__, dout_len);
  75. return -1;
  76. }
  77. /* Fill in args */
  78. args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
  79. args.command_version = cmd_version;
  80. args.data_size = dout_len;
  81. /* Calculate checksum */
  82. csum = cmd + args.flags + args.command_version + args.data_size;
  83. for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++)
  84. csum += *d;
  85. args.checksum = (uint8_t)csum;
  86. if (wait_for_sync(dev)) {
  87. debug("%s: Timeout waiting ready\n", __func__);
  88. return -1;
  89. }
  90. /* Write args */
  91. for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
  92. outb(*d, args_addr + i);
  93. /* Write data, if any */
  94. debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version);
  95. for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) {
  96. outb(*d, param_addr + i);
  97. debug_trace("%02x ", *d);
  98. }
  99. outb(cmd, cmd_addr);
  100. debug_trace("\n");
  101. if (wait_for_sync(dev)) {
  102. debug("%s: Timeout waiting for response\n", __func__);
  103. return -1;
  104. }
  105. /* Check result */
  106. i = inb(data_addr);
  107. if (i) {
  108. debug("%s: CROS_EC result code %d\n", __func__, i);
  109. return -i;
  110. }
  111. /* Read back args */
  112. for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
  113. *d = inb(args_addr + i);
  114. /*
  115. * If EC didn't modify args flags, then somehow we sent a new-style
  116. * command to an old EC, which means it would have read its params
  117. * from the wrong place.
  118. */
  119. if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) {
  120. debug("%s: CROS_EC protocol mismatch\n", __func__);
  121. return -EC_RES_INVALID_RESPONSE;
  122. }
  123. if (args.data_size > din_len) {
  124. debug("%s: CROS_EC returned too much data %d > %d\n",
  125. __func__, args.data_size, din_len);
  126. return -EC_RES_INVALID_RESPONSE;
  127. }
  128. /* Read data, if any */
  129. for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) {
  130. *d = inb(param_addr + i);
  131. debug_trace("%02x ", *d);
  132. }
  133. debug_trace("\n");
  134. /* Verify checksum */
  135. csum = cmd + args.flags + args.command_version + args.data_size;
  136. for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++)
  137. csum += *d;
  138. if (args.checksum != (uint8_t)csum) {
  139. debug("%s: CROS_EC response has invalid checksum\n", __func__);
  140. return -EC_RES_INVALID_CHECKSUM;
  141. }
  142. *dinp = dev->din;
  143. /* Return actual amount of data received */
  144. return args.data_size;
  145. }
  146. /**
  147. * Initialize LPC protocol.
  148. *
  149. * @param dev CROS_EC device
  150. * @param blob Device tree blob
  151. * @return 0 if ok, -1 on error
  152. */
  153. int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob)
  154. {
  155. int byte, i;
  156. /* See if we can find an EC at the other end */
  157. byte = 0xff;
  158. byte &= inb(EC_LPC_ADDR_HOST_CMD);
  159. byte &= inb(EC_LPC_ADDR_HOST_DATA);
  160. for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++)
  161. byte &= inb(EC_LPC_ADDR_HOST_PARAM + i);
  162. if (byte == 0xff) {
  163. debug("%s: CROS_EC device not found on LPC bus\n",
  164. __func__);
  165. return -1;
  166. }
  167. return 0;
  168. }
  169. /*
  170. * Test if LPC command args are supported.
  171. *
  172. * The cheapest way to do this is by looking for the memory-mapped
  173. * flag. This is faster than sending a new-style 'hello' command and
  174. * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag
  175. * in args when it responds.
  176. */
  177. static int cros_ec_lpc_check_version(struct udevice *dev)
  178. {
  179. if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' &&
  180. inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1)
  181. == 'C' &&
  182. (inb(EC_LPC_ADDR_MEMMAP +
  183. EC_MEMMAP_HOST_CMD_FLAGS) &
  184. EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) {
  185. return 0;
  186. }
  187. printf("%s: ERROR: old EC interface not supported\n", __func__);
  188. return -1;
  189. }
  190. static int cros_ec_probe(struct udevice *dev)
  191. {
  192. return cros_ec_register(dev);
  193. }
  194. static struct dm_cros_ec_ops cros_ec_ops = {
  195. .packet = cros_ec_lpc_packet,
  196. .command = cros_ec_lpc_command,
  197. .check_version = cros_ec_lpc_check_version,
  198. };
  199. static const struct udevice_id cros_ec_ids[] = {
  200. { .compatible = "google,cros-ec-lpc" },
  201. { }
  202. };
  203. U_BOOT_DRIVER(google_cros_ec_lpc) = {
  204. .name = "google_cros_ec_lpc",
  205. .id = UCLASS_CROS_EC,
  206. .of_match = cros_ec_ids,
  207. .probe = cros_ec_probe,
  208. .ops = &cros_ec_ops,
  209. };