altera_uart.c 3.2 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
  4. * Scott McNutt <smcnutt@psyent.com>
  5. */
  6. #include <common.h>
  7. #include <dm.h>
  8. #include <errno.h>
  9. #include <serial.h>
  10. #include <asm/io.h>
  11. /* status register */
  12. #define ALTERA_UART_TMT BIT(5) /* tx empty */
  13. #define ALTERA_UART_TRDY BIT(6) /* tx ready */
  14. #define ALTERA_UART_RRDY BIT(7) /* rx ready */
  15. struct altera_uart_regs {
  16. u32 rxdata; /* Rx data reg */
  17. u32 txdata; /* Tx data reg */
  18. u32 status; /* Status reg */
  19. u32 control; /* Control reg */
  20. u32 divisor; /* Baud rate divisor reg */
  21. u32 endofpacket; /* End-of-packet reg */
  22. };
  23. struct altera_uart_platdata {
  24. struct altera_uart_regs *regs;
  25. unsigned int uartclk;
  26. };
  27. static int altera_uart_setbrg(struct udevice *dev, int baudrate)
  28. {
  29. struct altera_uart_platdata *plat = dev->platdata;
  30. struct altera_uart_regs *const regs = plat->regs;
  31. u32 div;
  32. div = (plat->uartclk / baudrate) - 1;
  33. writel(div, &regs->divisor);
  34. return 0;
  35. }
  36. static int altera_uart_putc(struct udevice *dev, const char ch)
  37. {
  38. struct altera_uart_platdata *plat = dev->platdata;
  39. struct altera_uart_regs *const regs = plat->regs;
  40. if (!(readl(&regs->status) & ALTERA_UART_TRDY))
  41. return -EAGAIN;
  42. writel(ch, &regs->txdata);
  43. return 0;
  44. }
  45. static int altera_uart_pending(struct udevice *dev, bool input)
  46. {
  47. struct altera_uart_platdata *plat = dev->platdata;
  48. struct altera_uart_regs *const regs = plat->regs;
  49. u32 st = readl(&regs->status);
  50. if (input)
  51. return st & ALTERA_UART_RRDY ? 1 : 0;
  52. else
  53. return !(st & ALTERA_UART_TMT);
  54. }
  55. static int altera_uart_getc(struct udevice *dev)
  56. {
  57. struct altera_uart_platdata *plat = dev->platdata;
  58. struct altera_uart_regs *const regs = plat->regs;
  59. if (!(readl(&regs->status) & ALTERA_UART_RRDY))
  60. return -EAGAIN;
  61. return readl(&regs->rxdata) & 0xff;
  62. }
  63. static int altera_uart_probe(struct udevice *dev)
  64. {
  65. return 0;
  66. }
  67. static int altera_uart_ofdata_to_platdata(struct udevice *dev)
  68. {
  69. struct altera_uart_platdata *plat = dev_get_platdata(dev);
  70. plat->regs = map_physmem(devfdt_get_addr(dev),
  71. sizeof(struct altera_uart_regs),
  72. MAP_NOCACHE);
  73. plat->uartclk = dev_read_u32_default(dev, "clock-frequency", 0);
  74. return 0;
  75. }
  76. static const struct dm_serial_ops altera_uart_ops = {
  77. .putc = altera_uart_putc,
  78. .pending = altera_uart_pending,
  79. .getc = altera_uart_getc,
  80. .setbrg = altera_uart_setbrg,
  81. };
  82. static const struct udevice_id altera_uart_ids[] = {
  83. { .compatible = "altr,uart-1.0" },
  84. {}
  85. };
  86. U_BOOT_DRIVER(altera_uart) = {
  87. .name = "altera_uart",
  88. .id = UCLASS_SERIAL,
  89. .of_match = altera_uart_ids,
  90. .ofdata_to_platdata = altera_uart_ofdata_to_platdata,
  91. .platdata_auto_alloc_size = sizeof(struct altera_uart_platdata),
  92. .probe = altera_uart_probe,
  93. .ops = &altera_uart_ops,
  94. };
  95. #ifdef CONFIG_DEBUG_UART_ALTERA_UART
  96. #include <debug_uart.h>
  97. static inline void _debug_uart_init(void)
  98. {
  99. struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
  100. u32 div;
  101. div = (CONFIG_DEBUG_UART_CLOCK / CONFIG_BAUDRATE) - 1;
  102. writel(div, &regs->divisor);
  103. }
  104. static inline void _debug_uart_putc(int ch)
  105. {
  106. struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
  107. while (1) {
  108. u32 st = readl(&regs->status);
  109. if (st & ALTERA_UART_TRDY)
  110. break;
  111. }
  112. writel(ch, &regs->txdata);
  113. }
  114. DEBUG_UART_FUNCS
  115. #endif