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