drivers/serial/mcfuart.c

   1 /*
   2  * (C) Copyright 2004-2007 Freescale Semiconductor, Inc.
   3  * TsiChung Liew, Tsi-Chung.Liew@freescale.com.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * Minimal serial functions needed to use one of the uart ports
  10  * as serial console interface.
  11  */
  12
  13 #include <common.h>
  14 #include <serial.h>
  15 #include <linux/compiler.h>
  16
  17 #include <asm/immap.h>
  18 #include <asm/uart.h>
  19
  20 DECLARE_GLOBAL_DATA_PTR;
  21
  22 extern void uart_port_conf(int port);
  23
  24 static int mcf_serial_init(void)
  25 {
  26         volatile uart_t *uart;
  27         u32 counter;
  28
  29         uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
  30
  31         uart_port_conf(CONFIG_SYS_UART_PORT);
  32
  33         /* write to SICR: SIM2 = uart mode,dcd does not affect rx */
  34         uart->ucr = UART_UCR_RESET_RX;
  35         uart->ucr = UART_UCR_RESET_TX;
  36         uart->ucr = UART_UCR_RESET_ERROR;
  37         uart->ucr = UART_UCR_RESET_MR;
  38         __asm__("nop");
  39
  40         uart->uimr = 0;
  41
  42         /* write to CSR: RX/TX baud rate from timers */
  43         uart->ucsr = (UART_UCSR_RCS_SYS_CLK | UART_UCSR_TCS_SYS_CLK);
  44
  45         uart->umr = (UART_UMR_BC_8 | UART_UMR_PM_NONE);
  46         uart->umr = UART_UMR_SB_STOP_BITS_1;
  47
  48         /* Setting up BaudRate */
  49         counter = (u32) ((gd->bus_clk / 32) + (gd->baudrate / 2));
  50         counter = counter / gd->baudrate;
  51
  52         /* write to CTUR: divide counter upper byte */
  53         uart->ubg1 = (u8) ((counter & 0xff00) >> 8);
  54         /* write to CTLR: divide counter lower byte */
  55         uart->ubg2 = (u8) (counter & 0x00ff);
  56
  57         uart->ucr = (UART_UCR_RX_ENABLED | UART_UCR_TX_ENABLED);
  58
  59         return (0);
  60 }
  61
  62 static void mcf_serial_putc(const char c)
  63 {
  64         volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
  65
  66         if (c == '\n')
  67                 serial_putc('\r');
  68
  69         /* Wait for last character to go. */
  70         while (!(uart->usr & UART_USR_TXRDY)) ;
  71
  72         uart->utb = c;
  73 }
  74
  75 static int mcf_serial_getc(void)
  76 {
  77         volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
  78
  79         /* Wait for a character to arrive. */
  80         while (!(uart->usr & UART_USR_RXRDY)) ;
  81         return uart->urb;
  82 }
  83
  84 static int mcf_serial_tstc(void)
  85 {
  86         volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
  87
  88         return (uart->usr & UART_USR_RXRDY);
  89 }
  90
  91 static void mcf_serial_setbrg(void)
  92 {
  93         volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
  94         u32 counter;
  95
  96         /* Setting up BaudRate */
  97         counter = (u32) ((gd->bus_clk / 32) + (gd->baudrate / 2));
  98         counter = counter / gd->baudrate;
  99
 100         /* write to CTUR: divide counter upper byte */
 101         uart->ubg1 = ((counter & 0xff00) >> 8);
 102         /* write to CTLR: divide counter lower byte */
 103         uart->ubg2 = (counter & 0x00ff);
 104
 105         uart->ucr = UART_UCR_RESET_RX;
 106         uart->ucr = UART_UCR_RESET_TX;
 107
 108         uart->ucr = UART_UCR_RX_ENABLED | UART_UCR_TX_ENABLED;
 109 }
 110
 111 static struct serial_device mcf_serial_drv = {
 112         .name   = "mcf_serial",
 113         .start  = mcf_serial_init,
 114         .stop   = NULL,
 115         .setbrg = mcf_serial_setbrg,
 116         .putc   = mcf_serial_putc,
 117         .puts   = default_serial_puts,
 118         .getc   = mcf_serial_getc,
 119         .tstc   = mcf_serial_tstc,
 120 };
 121
 122 void mcf_serial_initialize(void)
 123 {
 124         serial_register(&mcf_serial_drv);
 125 }
 126
 127 __weak struct serial_device *default_serial_console(void)
 128 {
 129         return &mcf_serial_drv;
 130 }