lm3s69xx/console/uart.c

0001 /*
0002  * Copyright (c) 2013 Eugeniy Meshcheryakov <eugen@debian.org>
0003  *
0004  * Copyright (c) 2011 Sebastian Huber.  All rights reserved.
0005  *
0006  * The license and distribution terms for this file may be
0007  * found in the file LICENSE in this distribution or at
0008  * http://www.rtems.org/license/LICENSE.
0009  */
0010
0011 #include <bspopts.h>
0012 #include <bsp/uart.h>
0013 #include <libchip/sersupp.h>
0014 #include <bsp/syscon.h>
0015 #include <bsp/lm3s69xx.h>
0016 #include <rtems/irq-extension.h>
0017 #include <assert.h>
0018
0019 #define LM3S69XX_UART_FIFO_DEPTH 16
0020
0021 static volatile lm3s69xx_uart *get_uart_regs(int minor)
0022 {
0023   console_tbl *ct = Console_Port_Tbl [minor];
0024
0025   return (lm3s69xx_uart *) ct->ulCtrlPort1;
0026 }
0027
0028 static unsigned int get_uart_number(int minor)
0029 {
0030   console_tbl *ct = Console_Port_Tbl [minor];
0031
0032   return (unsigned int)ct->pDeviceParams;
0033 }
0034
0035 /*
0036  * Returns both integer and fractional parts as one number.
0037  */
0038 static uint32_t get_baud_div(uint32_t baud)
0039 {
0040   uint32_t clock4 = LM3S69XX_SYSTEM_CLOCK * 4;
0041   return (clock4 + baud - 1) / baud;
0042 }
0043
0044 static void irq_handler(void *arg)
0045 {
0046   int minor = (int)arg;
0047   console_data *cd = &Console_Port_Data [minor];
0048   volatile lm3s69xx_uart *uart = get_uart_regs(minor);
0049
0050   do {
0051     char buf[LM3S69XX_UART_FIFO_DEPTH];
0052     int i = 0;
0053     uint32_t status = uart->fr;
0054
0055     while (((status & UARTFR_RXFE) == 0) && (i < LM3S69XX_UART_FIFO_DEPTH)) {
0056       uint32_t d = uart->dr;
0057
0058       if ((d & UARTDR_ERROR_MSK) == 0) {
0059         buf[i] = UARTDR_DATA_GET(d);
0060         i++;
0061       }
0062
0063       status = uart->fr;
0064     }
0065
0066     if (i > 0)
0067       rtems_termios_enqueue_raw_characters(cd->termios_data, buf, i);
0068   } while (uart->mis != 0);
0069 }
0070
0071 static void initialize(int minor)
0072 {
0073   const console_tbl *ct = Console_Port_Tbl[minor];
0074   volatile lm3s69xx_uart *uart = get_uart_regs(minor);
0075   unsigned int num = get_uart_number(minor);
0076
0077   lm3s69xx_syscon_enable_uart_clock(num, true);
0078
0079   uart->ctl = 0;
0080
0081   uint32_t brd = get_baud_div(LM3S69XX_UART_BAUD);
0082   uart->ibrd = brd / 64;
0083   uart->fbrd = brd % 64;
0084
0085   uart->lcrh = UARTLCRH_WLEN(0x3) | UARTLCRH_FEN;
0086   uart->ctl = UARTCTL_RXE | UARTCTL_TXE | UARTCTL_UARTEN;
0087
0088   int rv = rtems_interrupt_handler_install(ct->ulIntVector, "UART",
0089       RTEMS_INTERRUPT_UNIQUE, irq_handler, (void *)minor);
0090   assert(rv == RTEMS_SUCCESSFUL);
0091 }
0092
0093 static int first_open(int major, int minor, void *arg)
0094 {
0095   rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *) arg;
0096   struct rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1;
0097   console_data *cd = &Console_Port_Data [minor];
0098   volatile lm3s69xx_uart *uart = get_uart_regs(minor);
0099
0100   cd->termios_data = tty;
0101   rtems_termios_set_initial_baud(tty, LM3S69XX_UART_BAUD);
0102
0103   /* Drain the RX FIFO. */
0104   while ((uart->fr & UARTFR_RXFE) == 0)
0105     (void)uart->dr;
0106
0107   uart->im = UARTI_RX | UARTI_RT;
0108
0109   return 0;
0110 }
0111
0112 static int last_close(int major, int minor, void *arg)
0113 {
0114   volatile lm3s69xx_uart *uart = get_uart_regs(minor);
0115   uart->im = 0;
0116
0117   return 0;
0118 }
0119
0120 static void write_polled(int minor, char c)
0121 {
0122   volatile lm3s69xx_uart *uart = get_uart_regs(minor);
0123
0124   while ((uart->fr & UARTFR_TXFF) != 0) {
0125     /* Wait */
0126   }
0127
0128   uart->dr = UARTDR_DATA(c);
0129 }
0130
0131 static ssize_t write_support_polled(
0132   int minor,
0133   const char *s,
0134   size_t n
0135 )
0136 {
0137   ssize_t i = 0;
0138
0139   for (i = 0; i < n; ++i) {
0140     write_polled(minor, s [i]);
0141   }
0142
0143   return n;
0144 }
0145
0146 static int set_attribues(int minor, const struct termios *term)
0147 {
0148   return -1;
0149 }
0150
0151 const console_fns lm3s69xx_uart_fns = {
0152   .deviceProbe = libchip_serial_default_probe,
0153   .deviceFirstOpen = first_open,
0154   .deviceLastClose = last_close,
0155   .deviceRead = NULL,
0156   .deviceWrite = write_support_polled,
0157   .deviceInitialize = initialize,
0158   .deviceWritePolled = write_polled,
0159   .deviceSetAttributes = set_attribues,
0160   .deviceOutputUsesInterrupts = false
0161 };