sbsa_gwdt.c 2.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Watchdog driver for SBSA
  4. *
  5. * Copyright 2020 NXP
  6. */
  7. #include <asm/io.h>
  8. #include <common.h>
  9. #include <dm/device.h>
  10. #include <dm/fdtaddr.h>
  11. #include <dm/read.h>
  12. #include <linux/bitops.h>
  13. #include <linux/err.h>
  14. #include <watchdog.h>
  15. #include <wdt.h>
  16. DECLARE_GLOBAL_DATA_PTR;
  17. /* SBSA Generic Watchdog register definitions */
  18. /* refresh frame */
  19. #define SBSA_GWDT_WRR 0x000
  20. /* control frame */
  21. #define SBSA_GWDT_WCS 0x000
  22. #define SBSA_GWDT_WOR 0x008
  23. #define SBSA_GWDT_WCV 0x010
  24. /* refresh/control frame */
  25. #define SBSA_GWDT_W_IIDR 0xfcc
  26. #define SBSA_GWDT_IDR 0xfd0
  27. /* Watchdog Control and Status Register */
  28. #define SBSA_GWDT_WCS_EN BIT(0)
  29. #define SBSA_GWDT_WCS_WS0 BIT(1)
  30. #define SBSA_GWDT_WCS_WS1 BIT(2)
  31. struct sbsa_gwdt_priv {
  32. void __iomem *reg_refresh;
  33. void __iomem *reg_control;
  34. };
  35. static int sbsa_gwdt_reset(struct udevice *dev)
  36. {
  37. struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
  38. writel(0, priv->reg_refresh + SBSA_GWDT_WRR);
  39. return 0;
  40. }
  41. static int sbsa_gwdt_start(struct udevice *dev, u64 timeout, ulong flags)
  42. {
  43. struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
  44. u32 clk;
  45. /*
  46. * it work in the single stage mode in u-boot,
  47. * The first signal (WS0) is ignored,
  48. * the timeout is (WOR * 2), so the WOR should be configured
  49. * to half value of timeout.
  50. */
  51. clk = get_tbclk();
  52. writel(clk / 2 * timeout,
  53. priv->reg_control + SBSA_GWDT_WOR);
  54. /* writing WCS will cause an explicit watchdog refresh */
  55. writel(SBSA_GWDT_WCS_EN, priv->reg_control + SBSA_GWDT_WCS);
  56. return 0;
  57. }
  58. static int sbsa_gwdt_stop(struct udevice *dev)
  59. {
  60. struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
  61. writel(0, priv->reg_control + SBSA_GWDT_WCS);
  62. return 0;
  63. }
  64. static int sbsa_gwdt_expire_now(struct udevice *dev, ulong flags)
  65. {
  66. sbsa_gwdt_start(dev, 0, flags);
  67. return 0;
  68. }
  69. static int sbsa_gwdt_probe(struct udevice *dev)
  70. {
  71. debug("%s: Probing wdt%u (sbsa-gwdt)\n", __func__, dev->seq);
  72. return 0;
  73. }
  74. static int sbsa_gwdt_ofdata_to_platdata(struct udevice *dev)
  75. {
  76. struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
  77. priv->reg_control = (void __iomem *)dev_read_addr_index(dev, 0);
  78. if (IS_ERR(priv->reg_control))
  79. return PTR_ERR(priv->reg_control);
  80. priv->reg_refresh = (void __iomem *)dev_read_addr_index(dev, 1);
  81. if (IS_ERR(priv->reg_refresh))
  82. return PTR_ERR(priv->reg_refresh);
  83. return 0;
  84. }
  85. static const struct wdt_ops sbsa_gwdt_ops = {
  86. .start = sbsa_gwdt_start,
  87. .reset = sbsa_gwdt_reset,
  88. .stop = sbsa_gwdt_stop,
  89. .expire_now = sbsa_gwdt_expire_now,
  90. };
  91. static const struct udevice_id sbsa_gwdt_ids[] = {
  92. { .compatible = "arm,sbsa-gwdt" },
  93. {}
  94. };
  95. U_BOOT_DRIVER(sbsa_gwdt) = {
  96. .name = "sbsa_gwdt",
  97. .id = UCLASS_WDT,
  98. .of_match = sbsa_gwdt_ids,
  99. .probe = sbsa_gwdt_probe,
  100. .priv_auto_alloc_size = sizeof(struct sbsa_gwdt_priv),
  101. .ofdata_to_platdata = sbsa_gwdt_ofdata_to_platdata,
  102. .ops = &sbsa_gwdt_ops,
  103. };