diff options
Diffstat (limited to 'drivers/serial/opencores_yanu.c')
| -rw-r--r-- | drivers/serial/opencores_yanu.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/serial/opencores_yanu.c b/drivers/serial/opencores_yanu.c new file mode 100644 index 0000000000..dacda5341e --- /dev/null +++ b/drivers/serial/opencores_yanu.c @@ -0,0 +1,188 @@ +/* + * Copyright 2010, Renato Andreola <renato.andreola@imagos.it> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <watchdog.h> +#include <asm/io.h> +#include <nios2-yanu.h> + +DECLARE_GLOBAL_DATA_PTR; + +/*-----------------------------------------------------------------*/ +/* YANU Imagos serial port */ +/*-----------------------------------------------------------------*/ + +static yanu_uart_t *uart = (yanu_uart_t *)CONFIG_SYS_NIOS_CONSOLE; + +#if defined(CONFIG_SYS_NIOS_FIXEDBAUD) + +/* Everything's already setup for fixed-baud PTF assignment*/ + +void serial_setbrg (void) +{ + int n, k; + const unsigned max_uns = 0xFFFFFFFF; + unsigned best_n, best_m, baud; + + /* compute best N and M couple */ + best_n = YANU_MAX_PRESCALER_N; + for (n = YANU_MAX_PRESCALER_N; n >= 0; n--) { + if ((unsigned)CONFIG_SYS_CLK_FREQ / (1 << (n + 4)) >= + (unsigned)CONFIG_BAUDRATE) { + best_n = n; + break; + } + } + for (k = 0;; k++) { + if ((unsigned)CONFIG_BAUDRATE <= (max_uns >> (15+n-k))) + break; + } + best_m = + ((unsigned)CONFIG_BAUDRATE * (1 << (15 + n - k))) / + ((unsigned)CONFIG_SYS_CLK_FREQ >> k); + + baud = best_m + best_n * YANU_BAUDE; + writel(&uart->baud, baud); + + return; +} + +#else + +void serial_setbrg (void) +{ + int n, k; + const unsigned max_uns = 0xFFFFFFFF; + unsigned best_n, best_m, baud; + + /* compute best N and M couple */ + best_n = YANU_MAX_PRESCALER_N; + for (n = YANU_MAX_PRESCALER_N; n >= 0; n--) { + if ((unsigned)CONFIG_SYS_CLK_FREQ / (1 << (n + 4)) >= + gd->baudrate) { + best_n = n; + break; + } + } + for (k = 0;; k++) { + if (gd->baudrate <= (max_uns >> (15+n-k))) + break; + } + best_m = + (gd->baudrate * (1 << (15 + n - k))) / + ((unsigned)CONFIG_SYS_CLK_FREQ >> k); + + baud = best_m + best_n * YANU_BAUDE; + writel(&uart->baud, baud); + + return; +} + + +#endif /* CONFIG_SYS_NIOS_FIXEDBAUD */ + +int serial_init (void) +{ + unsigned action,control; + + /* status register cleanup */ + action = YANU_ACTION_RRRDY | + YANU_ACTION_RTRDY | + YANU_ACTION_ROE | + YANU_ACTION_RBRK | + YANU_ACTION_RFE | + YANU_ACTION_RPE | + YANU_ACTION_RFE | YANU_ACTION_RFIFO_CLEAR | YANU_ACTION_TFIFO_CLEAR; + + writel(&uart->action, action); + + /* control register cleanup */ + /* no interrupts enabled */ + /* one stop bit */ + /* hardware flow control disabled */ + /* 8 bits */ + control = (0x7 << YANU_CONTROL_BITS_POS); + /* enven parity just to be clean */ + control |= YANU_CONTROL_PAREVEN; + /* we set threshold for fifo */ + control |= YANU_CONTROL_RDYDLY * YANU_RXFIFO_DLY; + control |= YANU_CONTROL_TXTHR * YANU_TXFIFO_THR; + + writel(&uart->control, control); + + /* to set baud rate */ + serial_setbrg(); + + return (0); +} + + +/*----------------------------------------------------------------------- + * YANU CONSOLE + *---------------------------------------------------------------------*/ +void serial_putc (char c) +{ + int tx_chars; + unsigned status; + + if (c == '\n') + serial_putc ('\r'); + + while (1) { + status = readl(&uart->status); + tx_chars = (status>>YANU_TFIFO_CHARS_POS) + & ((1<<YANU_TFIFO_CHARS_N)-1); + if (tx_chars < YANU_TXFIFO_SIZE-1) + break; + WATCHDOG_RESET (); + } + + writel(&uart->data, (unsigned char)c); +} + +void serial_puts (const char *s) +{ + while (*s != 0) { + serial_putc (*s++); + } +} + + +int serial_tstc(void) +{ + unsigned status ; + + status = readl(&uart->status); + return (((status >> YANU_RFIFO_CHARS_POS) & + ((1 << YANU_RFIFO_CHARS_N) - 1)) > 0); +} + +int serial_getc (void) +{ + while (serial_tstc() == 0) + WATCHDOG_RESET (); + + /* first we pull the char */ + writel(&uart->action, YANU_ACTION_RFIFO_PULL); + + return(readl(&uart->data) & YANU_DATA_CHAR_MASK); +} |
