sbi_ecall.c 3.4 KB

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  1. /*
  2. * SPDX-License-Identifier: BSD-2-Clause
  3. *
  4. * Copyright (c) 2019 Western Digital Corporation or its affiliates.
  5. *
  6. * Authors:
  7. * Anup Patel <anup.patel@wdc.com>
  8. */
  9. #include <sbi/sbi_console.h>
  10. #include <sbi/sbi_ecall.h>
  11. #include <sbi/sbi_ecall_interface.h>
  12. #include <sbi/sbi_error.h>
  13. #include <sbi/sbi_trap.h>
  14. extern struct sbi_ecall_extension *sbi_ecall_exts[];
  15. extern unsigned long sbi_ecall_exts_size;
  16. u16 sbi_ecall_version_major(void)
  17. {
  18. return SBI_ECALL_VERSION_MAJOR;
  19. }
  20. u16 sbi_ecall_version_minor(void)
  21. {
  22. return SBI_ECALL_VERSION_MINOR;
  23. }
  24. static unsigned long ecall_impid = SBI_OPENSBI_IMPID;
  25. unsigned long sbi_ecall_get_impid(void)
  26. {
  27. return ecall_impid;
  28. }
  29. void sbi_ecall_set_impid(unsigned long impid)
  30. {
  31. ecall_impid = impid;
  32. }
  33. static SBI_LIST_HEAD(ecall_exts_list);
  34. struct sbi_ecall_extension *sbi_ecall_find_extension(unsigned long extid)
  35. {
  36. struct sbi_ecall_extension *t, *ret = NULL;
  37. sbi_list_for_each_entry(t, &ecall_exts_list, head) {
  38. if (t->extid_start <= extid && extid <= t->extid_end) {
  39. ret = t;
  40. break;
  41. }
  42. }
  43. return ret;
  44. }
  45. int sbi_ecall_register_extension(struct sbi_ecall_extension *ext)
  46. {
  47. struct sbi_ecall_extension *t;
  48. if (!ext || (ext->extid_end < ext->extid_start) || !ext->handle)
  49. return SBI_EINVAL;
  50. sbi_list_for_each_entry(t, &ecall_exts_list, head) {
  51. unsigned long start = t->extid_start;
  52. unsigned long end = t->extid_end;
  53. if (end < ext->extid_start || ext->extid_end < start)
  54. /* no overlap */;
  55. else
  56. return SBI_EINVAL;
  57. }
  58. SBI_INIT_LIST_HEAD(&ext->head);
  59. sbi_list_add_tail(&ext->head, &ecall_exts_list);
  60. return 0;
  61. }
  62. void sbi_ecall_unregister_extension(struct sbi_ecall_extension *ext)
  63. {
  64. bool found = false;
  65. struct sbi_ecall_extension *t;
  66. if (!ext)
  67. return;
  68. sbi_list_for_each_entry(t, &ecall_exts_list, head) {
  69. if (t == ext) {
  70. found = true;
  71. break;
  72. }
  73. }
  74. if (found)
  75. sbi_list_del_init(&ext->head);
  76. }
  77. int sbi_ecall_handler(struct sbi_trap_regs *regs)
  78. {
  79. int ret = 0;
  80. struct sbi_ecall_extension *ext;
  81. unsigned long extension_id = regs->a7;
  82. unsigned long func_id = regs->a6;
  83. struct sbi_trap_info trap = {0};
  84. unsigned long out_val = 0;
  85. bool is_0_1_spec = 0;
  86. ext = sbi_ecall_find_extension(extension_id);
  87. if (ext && ext->handle) {
  88. ret = ext->handle(extension_id, func_id,
  89. regs, &out_val, &trap);
  90. if (extension_id >= SBI_EXT_0_1_SET_TIMER &&
  91. extension_id <= SBI_EXT_0_1_SHUTDOWN)
  92. is_0_1_spec = 1;
  93. } else {
  94. ret = SBI_ENOTSUPP;
  95. }
  96. if (ret == SBI_ETRAP) {
  97. trap.epc = regs->mepc;
  98. sbi_trap_redirect(regs, &trap);
  99. } else {
  100. if (ret < SBI_LAST_ERR || SBI_SUCCESS < ret) {
  101. sbi_printf("%s: Invalid error %d for ext=0x%lx "
  102. "func=0x%lx\n", __func__, ret,
  103. extension_id, func_id);
  104. ret = SBI_ERR_FAILED;
  105. }
  106. /*
  107. * This function should return non-zero value only in case of
  108. * fatal error. However, there is no good way to distinguish
  109. * between a fatal and non-fatal errors yet. That's why we treat
  110. * every return value except ETRAP as non-fatal and just return
  111. * accordingly for now. Once fatal errors are defined, that
  112. * case should be handled differently.
  113. */
  114. regs->mepc += 4;
  115. regs->a0 = ret;
  116. if (!is_0_1_spec)
  117. regs->a1 = out_val;
  118. }
  119. return 0;
  120. }
  121. int sbi_ecall_init(void)
  122. {
  123. int ret;
  124. struct sbi_ecall_extension *ext;
  125. unsigned long i;
  126. for (i = 0; i < sbi_ecall_exts_size; i++) {
  127. ext = sbi_ecall_exts[i];
  128. ret = sbi_ecall_register_extension(ext);
  129. if (ret)
  130. return ret;
  131. }
  132. return 0;
  133. }