forked from Imagelibrary/rtems
168 lines
3.5 KiB
C
168 lines
3.5 KiB
C
/**
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* @file
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*
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* @ingroup raspberrypi_usart
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*
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* @brief USART support.
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*/
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/*
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* Copyright (c) 2013 Alan Cudmore
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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*
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* http://www.rtems.org/license/LICENSE
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*
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*/
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#include <libchip/sersupp.h>
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#include <bsp.h>
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#include <bsp/irq.h>
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#include <bsp/usart.h>
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#include <bsp/raspberrypi.h>
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#include <rtems/bspIo.h>
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static void usart_delay(uint32_t n)
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{
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volatile uint32_t i = 0;
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for(i = 0; i < n; i++)
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;
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}
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#if 0
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/*
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* These will be useful when the driver supports interrupt driven IO.
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*/
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static rtems_vector_number usart_get_irq_number(const console_tbl *ct)
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{
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return ct->ulIntVector;
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}
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static uint32_t usart_get_baud(const console_tbl *ct)
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{
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return ct->ulClock;
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}
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#endif
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static void usart_set_baud(int minor, int baud)
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{
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/*
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* Nothing for now
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*/
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return;
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}
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static void usart_initialize(int minor)
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{
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unsigned int gpio_reg;
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/*
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** Program GPIO pins for UART 0
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*/
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gpio_reg = BCM2835_REG(BCM2835_GPIO_GPFSEL1);
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gpio_reg &= ~(7<<12); /* gpio14 */
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gpio_reg |= (4<<12); /* alt0 */
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gpio_reg &= ~(7<<15); /* gpio15 */
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gpio_reg |= (4<<15); /* alt0 */
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BCM2835_REG(BCM2835_GPIO_GPFSEL1) = gpio_reg;
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BCM2835_REG(BCM2835_GPIO_GPPUD) = 0;
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usart_delay(150);
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BCM2835_REG(BCM2835_GPIO_GPPUDCLK0) = (1<<14)|(1<<15);
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usart_delay(150);
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BCM2835_REG(BCM2835_GPIO_GPPUDCLK0) = 0;
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/*
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** Init the PL011 UART
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*/
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BCM2835_REG(BCM2835_UART0_CR) = 0;
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BCM2835_REG(BCM2835_UART0_ICR) = 0x7FF;
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BCM2835_REG(BCM2835_UART0_IMSC) = 0;
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BCM2835_REG(BCM2835_UART0_IBRD) = 1;
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BCM2835_REG(BCM2835_UART0_FBRD) = 40;
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BCM2835_REG(BCM2835_UART0_LCRH) = 0x70;
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BCM2835_REG(BCM2835_UART0_RSRECR) = 0;
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BCM2835_REG(BCM2835_UART0_CR) = 0x301;
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BCM2835_REG(BCM2835_UART0_IMSC) = BCM2835_UART0_IMSC_RX;
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usart_set_baud(minor, 115000);
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}
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static int usart_first_open(int major, int minor, void *arg)
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{
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rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *) arg;
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struct rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1;
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const console_tbl *ct = Console_Port_Tbl [minor];
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console_data *cd = &Console_Port_Data [minor];
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cd->termios_data = tty;
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rtems_termios_set_initial_baud(tty, ct->ulClock);
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return 0;
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}
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static int usart_last_close(int major, int minor, void *arg)
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{
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return 0;
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}
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static int usart_read_polled(int minor)
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{
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if (minor == 0) {
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if (((BCM2835_REG(BCM2835_UART0_FR)) & BCM2835_UART0_FR_RXFE) == 0) {
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return((BCM2835_REG(BCM2835_UART0_DR)) & 0xFF );
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} else {
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return -1;
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}
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} else {
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printk("Unknown console minor number: %d\n", minor);
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return -1;
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}
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}
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static void usart_write_polled(int minor, char c)
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{
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while (1) {
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if ((BCM2835_REG(BCM2835_UART0_FR) & BCM2835_UART0_FR_TXFF) == 0)
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break;
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}
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BCM2835_REG(BCM2835_UART0_DR) = c;
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}
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static ssize_t usart_write_support_polled(
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int minor,
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const char *s,
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size_t n
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)
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{
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ssize_t i = 0;
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for (i = 0; i < n; ++i) {
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usart_write_polled(minor, s [i]);
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}
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return n;
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}
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static int usart_set_attributes(int minor, const struct termios *term)
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{
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return -1;
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}
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const console_fns bcm2835_usart_fns = {
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.deviceProbe = libchip_serial_default_probe,
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.deviceFirstOpen = usart_first_open,
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.deviceLastClose = usart_last_close,
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.deviceRead = usart_read_polled,
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.deviceWrite = usart_write_support_polled,
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.deviceInitialize = usart_initialize,
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.deviceWritePolled = usart_write_polled,
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.deviceSetAttributes = usart_set_attributes,
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.deviceOutputUsesInterrupts = false
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};
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