2 * Copyright (c) 2015, Linaro Limited
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9 * this list of conditions and the following disclaimer.
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30 #include <drivers/serial8250_uart.h>
35 /* uart register defines */
47 /* uart status register bits */
48 #define LSR_TEMT 0x40 /* Transmitter empty */
49 #define LSR_THRE 0x20 /* Transmit-hold-register empty */
50 #define LSR_EMPTY (LSR_TEMT | LSR_THRE)
51 #define LSR_DR 0x01 /* DATA Ready */
53 static vaddr_t chip_to_base(struct serial_chip *chip)
55 struct serial8250_uart_data *pd =
56 container_of(chip, struct serial8250_uart_data, chip);
58 return io_pa_or_va(&pd->base);
61 static void serial8250_uart_flush(struct serial_chip *chip)
63 vaddr_t base = chip_to_base(chip);
66 uint8_t state = read8(base + UART_LSR);
68 /* Wait until transmit FIFO is empty */
69 if ((state & LSR_EMPTY) == LSR_EMPTY)
74 static bool serial8250_uart_have_rx_data(struct serial_chip *chip)
76 vaddr_t base = chip_to_base(chip);
78 return (read32(base + UART_LSR) & LSR_DR);
81 static int serial8250_uart_getchar(struct serial_chip *chip)
83 vaddr_t base = chip_to_base(chip);
85 while (!serial8250_uart_have_rx_data(chip)) {
86 /* Transmit FIFO is empty, waiting again */
89 return read8(base + UART_RHR);
92 static void serial8250_uart_putc(struct serial_chip *chip, int ch)
94 vaddr_t base = chip_to_base(chip);
96 serial8250_uart_flush(chip);
98 /* Write out character to transmit FIFO */
99 write8(ch, base + UART_THR);
102 static const struct serial_ops serial8250_uart_ops = {
103 .flush = serial8250_uart_flush,
104 .getchar = serial8250_uart_getchar,
105 .have_rx_data = serial8250_uart_have_rx_data,
106 .putc = serial8250_uart_putc,
108 KEEP_PAGER(serial8250_uart_ops);
110 void serial8250_uart_init(struct serial8250_uart_data *pd, paddr_t base,
111 uint32_t __unused uart_clk,
112 uint32_t __unused baud_rate)
116 pd->chip.ops = &serial8250_uart_ops;
119 * do nothing, debug uart(uart0) share with normal world,
120 * everything for uart0 is ready now.