4 * Qi Hardware, Xiangfu Liu <xiangfu@sharism.cc>
6 * SPDX-License-Identifier: GPL-2.0+
12 #include <asm/jz4740.h>
14 #include <linux/compiler.h>
17 * serial_init - initialize a channel
19 * This routine initializes the number of data bits, parity
20 * and set the selected baud rate. Interrupts are disabled.
21 * Set the modem control signals if the option is selected.
25 struct jz4740_uart *uart = (struct jz4740_uart *)CONFIG_SYS_UART_BASE;
27 static int jz_serial_init(void)
29 /* Disable port interrupts while changing hardware */
30 writeb(0, &uart->dlhr_ier);
32 /* Disable UART unit function */
33 writeb(~UART_FCR_UUE, &uart->iir_fcr);
35 /* Set both receiver and transmitter in UART mode (not SIR) */
36 writeb(~(SIRCR_RSIRE | SIRCR_TSIRE), &uart->isr);
39 * Set databits, stopbits and parity.
40 * (8-bit data, 1 stopbit, no parity)
42 writeb(UART_LCR_WLEN_8 | UART_LCR_STOP_1, &uart->lcr);
47 /* Enable UART unit, enable and clear FIFO */
48 writeb(UART_FCR_UUE | UART_FCR_FE | UART_FCR_TFLS | UART_FCR_RFLS,
54 static void jz_serial_setbrg(void)
58 baud_div = CONFIG_SYS_EXTAL / 16 / CONFIG_BAUDRATE;
60 tmp = readb(&uart->lcr);
62 writeb(tmp, &uart->lcr);
64 writeb((baud_div >> 8) & 0xff, &uart->dlhr_ier);
65 writeb(baud_div & 0xff, &uart->rbr_thr_dllr);
67 tmp &= ~UART_LCR_DLAB;
68 writeb(tmp, &uart->lcr);
71 static int jz_serial_tstc(void)
73 if (readb(&uart->lsr) & UART_LSR_DR)
79 static void jz_serial_putc(const char c)
84 /* Wait for fifo to shift out some bytes */
85 while (!((readb(&uart->lsr) & (UART_LSR_TDRQ | UART_LSR_TEMT)) == 0x60))
88 writeb((u8)c, &uart->rbr_thr_dllr);
91 static int jz_serial_getc(void)
93 while (!serial_tstc())
96 return readb(&uart->rbr_thr_dllr);
99 static struct serial_device jz_serial_drv = {
101 .start = jz_serial_init,
103 .setbrg = jz_serial_setbrg,
104 .putc = jz_serial_putc,
105 .puts = default_serial_puts,
106 .getc = jz_serial_getc,
107 .tstc = jz_serial_tstc,
110 void jz_serial_initialize(void)
112 serial_register(&jz_serial_drv);
115 __weak struct serial_device *default_serial_console(void)
117 return &jz_serial_drv;