serial_owl.c 3.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Actions Semi OWL SoCs UART driver
  4. *
  5. * Copyright (C) 2015 Actions Semi Co., Ltd.
  6. * Copyright (C) 2018 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
  7. */
  8. #include <common.h>
  9. #include <clk.h>
  10. #include <dm.h>
  11. #include <errno.h>
  12. #include <fdtdec.h>
  13. #include <serial.h>
  14. #include <asm/io.h>
  15. #include <asm/types.h>
  16. /* UART Registers */
  17. #define OWL_UART_CTL (0x0000)
  18. #define OWL_UART_RXDAT (0x0004)
  19. #define OWL_UART_TXDAT (0x0008)
  20. #define OWL_UART_STAT (0x000C)
  21. /* UART_CTL Register Definitions */
  22. #define OWL_UART_CTL_PRS_NONE GENMASK(6, 4)
  23. #define OWL_UART_CTL_STPS BIT(2)
  24. #define OWL_UART_CTL_DWLS 3
  25. /* UART_STAT Register Definitions */
  26. #define OWL_UART_STAT_TFES BIT(10) /* TX FIFO Empty Status */
  27. #define OWL_UART_STAT_RFFS BIT(9) /* RX FIFO full Status */
  28. #define OWL_UART_STAT_TFFU BIT(6) /* TX FIFO full Status */
  29. #define OWL_UART_STAT_RFEM BIT(5) /* RX FIFO Empty Status */
  30. struct owl_serial_priv {
  31. phys_addr_t base;
  32. };
  33. int owl_serial_setbrg(struct udevice *dev, int baudrate)
  34. {
  35. /* Driver supports only fixed baudrate */
  36. return 0;
  37. }
  38. static int owl_serial_getc(struct udevice *dev)
  39. {
  40. struct owl_serial_priv *priv = dev_get_priv(dev);
  41. if (readl(priv->base + OWL_UART_STAT) & OWL_UART_STAT_RFEM)
  42. return -EAGAIN;
  43. return (int)(readl(priv->base + OWL_UART_RXDAT));
  44. }
  45. static int owl_serial_putc(struct udevice *dev, const char ch)
  46. {
  47. struct owl_serial_priv *priv = dev_get_priv(dev);
  48. if (readl(priv->base + OWL_UART_STAT) & OWL_UART_STAT_TFFU)
  49. return -EAGAIN;
  50. writel(ch, priv->base + OWL_UART_TXDAT);
  51. return 0;
  52. }
  53. static int owl_serial_pending(struct udevice *dev, bool input)
  54. {
  55. struct owl_serial_priv *priv = dev_get_priv(dev);
  56. unsigned int stat = readl(priv->base + OWL_UART_STAT);
  57. if (input)
  58. return !(stat & OWL_UART_STAT_RFEM);
  59. else
  60. return !(stat & OWL_UART_STAT_TFES);
  61. }
  62. static int owl_serial_probe(struct udevice *dev)
  63. {
  64. struct owl_serial_priv *priv = dev_get_priv(dev);
  65. struct clk clk;
  66. u32 uart_ctl;
  67. int ret;
  68. /* Set data, parity and stop bits */
  69. uart_ctl = readl(priv->base + OWL_UART_CTL);
  70. uart_ctl &= ~(OWL_UART_CTL_PRS_NONE);
  71. uart_ctl &= ~(OWL_UART_CTL_STPS);
  72. uart_ctl |= OWL_UART_CTL_DWLS;
  73. writel(uart_ctl, priv->base + OWL_UART_CTL);
  74. /* Enable UART clock */
  75. ret = clk_get_by_index(dev, 0, &clk);
  76. if (ret < 0)
  77. return ret;
  78. ret = clk_enable(&clk);
  79. if (ret < 0)
  80. return ret;
  81. return 0;
  82. }
  83. static int owl_serial_ofdata_to_platdata(struct udevice *dev)
  84. {
  85. struct owl_serial_priv *priv = dev_get_priv(dev);
  86. priv->base = dev_read_addr(dev);
  87. if (priv->base == FDT_ADDR_T_NONE)
  88. return -EINVAL;
  89. return 0;
  90. }
  91. static const struct dm_serial_ops owl_serial_ops = {
  92. .putc = owl_serial_putc,
  93. .pending = owl_serial_pending,
  94. .getc = owl_serial_getc,
  95. .setbrg = owl_serial_setbrg,
  96. };
  97. static const struct udevice_id owl_serial_ids[] = {
  98. { .compatible = "actions,owl-uart" },
  99. { }
  100. };
  101. U_BOOT_DRIVER(serial_owl) = {
  102. .name = "serial_owl",
  103. .id = UCLASS_SERIAL,
  104. .of_match = owl_serial_ids,
  105. .ofdata_to_platdata = owl_serial_ofdata_to_platdata,
  106. .priv_auto_alloc_size = sizeof(struct owl_serial_priv),
  107. .probe = owl_serial_probe,
  108. .ops = &owl_serial_ops,
  109. };