scpi_pm_domain.c 3.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * SCPI Generic power domain support.
  4. *
  5. * Copyright (C) 2016 ARM Ltd.
  6. */
  7. #include <linux/err.h>
  8. #include <linux/io.h>
  9. #include <linux/module.h>
  10. #include <linux/of_platform.h>
  11. #include <linux/pm_domain.h>
  12. #include <linux/scpi_protocol.h>
  13. struct scpi_pm_domain {
  14. struct generic_pm_domain genpd;
  15. struct scpi_ops *ops;
  16. u32 domain;
  17. };
  18. /*
  19. * These device power state values are not well-defined in the specification.
  20. * In case, different implementations use different values, we can make these
  21. * specific to compatibles rather than getting these values from device tree.
  22. */
  23. enum scpi_power_domain_state {
  24. SCPI_PD_STATE_ON = 0,
  25. SCPI_PD_STATE_OFF = 3,
  26. };
  27. #define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd)
  28. static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on)
  29. {
  30. int ret;
  31. enum scpi_power_domain_state state;
  32. if (power_on)
  33. state = SCPI_PD_STATE_ON;
  34. else
  35. state = SCPI_PD_STATE_OFF;
  36. ret = pd->ops->device_set_power_state(pd->domain, state);
  37. if (ret)
  38. return ret;
  39. return !(state == pd->ops->device_get_power_state(pd->domain));
  40. }
  41. static int scpi_pd_power_on(struct generic_pm_domain *domain)
  42. {
  43. struct scpi_pm_domain *pd = to_scpi_pd(domain);
  44. return scpi_pd_power(pd, true);
  45. }
  46. static int scpi_pd_power_off(struct generic_pm_domain *domain)
  47. {
  48. struct scpi_pm_domain *pd = to_scpi_pd(domain);
  49. return scpi_pd_power(pd, false);
  50. }
  51. static int scpi_pm_domain_probe(struct platform_device *pdev)
  52. {
  53. struct device *dev = &pdev->dev;
  54. struct device_node *np = dev->of_node;
  55. struct scpi_pm_domain *scpi_pd;
  56. struct genpd_onecell_data *scpi_pd_data;
  57. struct generic_pm_domain **domains;
  58. struct scpi_ops *scpi_ops;
  59. int ret, num_domains, i;
  60. scpi_ops = get_scpi_ops();
  61. if (!scpi_ops)
  62. return -EPROBE_DEFER;
  63. if (!np) {
  64. dev_err(dev, "device tree node not found\n");
  65. return -ENODEV;
  66. }
  67. if (!scpi_ops->device_set_power_state ||
  68. !scpi_ops->device_get_power_state) {
  69. dev_err(dev, "power domains not supported in the firmware\n");
  70. return -ENODEV;
  71. }
  72. ret = of_property_read_u32(np, "num-domains", &num_domains);
  73. if (ret) {
  74. dev_err(dev, "number of domains not found\n");
  75. return -EINVAL;
  76. }
  77. scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL);
  78. if (!scpi_pd)
  79. return -ENOMEM;
  80. scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL);
  81. if (!scpi_pd_data)
  82. return -ENOMEM;
  83. domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
  84. if (!domains)
  85. return -ENOMEM;
  86. for (i = 0; i < num_domains; i++, scpi_pd++) {
  87. domains[i] = &scpi_pd->genpd;
  88. scpi_pd->domain = i;
  89. scpi_pd->ops = scpi_ops;
  90. scpi_pd->genpd.name = devm_kasprintf(dev, GFP_KERNEL,
  91. "%pOFn.%d", np, i);
  92. if (!scpi_pd->genpd.name) {
  93. dev_err(dev, "Failed to allocate genpd name:%pOFn.%d\n",
  94. np, i);
  95. continue;
  96. }
  97. scpi_pd->genpd.power_off = scpi_pd_power_off;
  98. scpi_pd->genpd.power_on = scpi_pd_power_on;
  99. /*
  100. * Treat all power domains as off at boot.
  101. *
  102. * The SCP firmware itself may have switched on some domains,
  103. * but for reference counting purpose, keep it this way.
  104. */
  105. pm_genpd_init(&scpi_pd->genpd, NULL, true);
  106. }
  107. scpi_pd_data->domains = domains;
  108. scpi_pd_data->num_domains = num_domains;
  109. of_genpd_add_provider_onecell(np, scpi_pd_data);
  110. return 0;
  111. }
  112. static const struct of_device_id scpi_power_domain_ids[] = {
  113. { .compatible = "arm,scpi-power-domains", },
  114. { /* sentinel */ }
  115. };
  116. MODULE_DEVICE_TABLE(of, scpi_power_domain_ids);
  117. static struct platform_driver scpi_power_domain_driver = {
  118. .driver = {
  119. .name = "scpi_power_domain",
  120. .of_match_table = scpi_power_domain_ids,
  121. },
  122. .probe = scpi_pm_domain_probe,
  123. };
  124. module_platform_driver(scpi_power_domain_driver);
  125. MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
  126. MODULE_DESCRIPTION("ARM SCPI power domain driver");
  127. MODULE_LICENSE("GPL v2");