axxia-reset.c 2.2 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Reset driver for Axxia devices
  4. *
  5. * Copyright (C) 2014 LSI
  6. */
  7. #include <linux/init.h>
  8. #include <linux/err.h>
  9. #include <linux/io.h>
  10. #include <linux/kernel.h>
  11. #include <linux/mfd/syscon.h>
  12. #include <linux/module.h>
  13. #include <linux/notifier.h>
  14. #include <linux/of.h>
  15. #include <linux/platform_device.h>
  16. #include <linux/reboot.h>
  17. #include <linux/regmap.h>
  18. #define SC_CRIT_WRITE_KEY 0x1000
  19. #define SC_LATCH_ON_RESET 0x1004
  20. #define SC_RESET_CONTROL 0x1008
  21. #define RSTCTL_RST_ZERO (1<<3)
  22. #define RSTCTL_RST_FAB (1<<2)
  23. #define RSTCTL_RST_CHIP (1<<1)
  24. #define RSTCTL_RST_SYS (1<<0)
  25. #define SC_EFUSE_INT_STATUS 0x180c
  26. #define EFUSE_READ_DONE (1<<31)
  27. static struct regmap *syscon;
  28. static int axxia_restart_handler(struct notifier_block *this,
  29. unsigned long mode, void *cmd)
  30. {
  31. /* Access Key (0xab) */
  32. regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
  33. /* Select internal boot from 0xffff0000 */
  34. regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
  35. /* Assert ResetReadDone (to avoid hanging in boot ROM) */
  36. regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
  37. /* Assert chip reset */
  38. regmap_update_bits(syscon, SC_RESET_CONTROL,
  39. RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
  40. return NOTIFY_DONE;
  41. }
  42. static struct notifier_block axxia_restart_nb = {
  43. .notifier_call = axxia_restart_handler,
  44. .priority = 128,
  45. };
  46. static int axxia_reset_probe(struct platform_device *pdev)
  47. {
  48. struct device *dev = &pdev->dev;
  49. int err;
  50. syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
  51. if (IS_ERR(syscon)) {
  52. pr_err("%pOFn: syscon lookup failed\n", dev->of_node);
  53. return PTR_ERR(syscon);
  54. }
  55. err = register_restart_handler(&axxia_restart_nb);
  56. if (err)
  57. dev_err(dev, "cannot register restart handler (err=%d)\n", err);
  58. return err;
  59. }
  60. static const struct of_device_id of_axxia_reset_match[] = {
  61. { .compatible = "lsi,axm55xx-reset", },
  62. {},
  63. };
  64. MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
  65. static struct platform_driver axxia_reset_driver = {
  66. .probe = axxia_reset_probe,
  67. .driver = {
  68. .name = "axxia-reset",
  69. .of_match_table = of_match_ptr(of_axxia_reset_match),
  70. },
  71. };
  72. static int __init axxia_reset_init(void)
  73. {
  74. return platform_driver_register(&axxia_reset_driver);
  75. }
  76. device_initcall(axxia_reset_init);