/* * Altera NiosII YANU serial interface by Imagos * please see http://www.opencores.org/project,yanu for * information/downloads * * Copyright 2010, Renato Andreola <renato.andreola@imagos.it> * * SPDX-License-Identifier: GPL-2.0+ */ #include <common.h> #include <watchdog.h> #include <asm/io.h> #include <serial.h> DECLARE_GLOBAL_DATA_PTR; /*-----------------------------------------------------------------*/ /* YANU Imagos serial port */ /*-----------------------------------------------------------------*/ #define YANU_MAX_PRESCALER_N ((1 << 4) - 1) /* 15 */ #define YANU_MAX_PRESCALER_M ((1 << 11) -1) /* 2047 */ #define YANU_FIFO_SIZE (16) #define YANU_RXFIFO_SIZE (YANU_FIFO_SIZE) #define YANU_TXFIFO_SIZE (YANU_FIFO_SIZE) #define YANU_RXFIFO_DLY (10*11) #define YANU_TXFIFO_THR (10) #define YANU_DATA_CHAR_MASK (0xFF) /* data register */ #define YANU_DATA_OFFSET (0) /* data register offset */ #define YANU_CONTROL_OFFSET (4) /* control register offset */ /* interrupt enable */ #define YANU_CONTROL_IE_RRDY (1<<0) /* ie on received character ready */ #define YANU_CONTROL_IE_OE (1<<1) /* ie on rx overrun */ #define YANU_CONTROL_IE_BRK (1<<2) /* ie on break detect */ #define YANU_CONTROL_IE_FE (1<<3) /* ie on framing error */ #define YANU_CONTROL_IE_PE (1<<4) /* ie on parity error */ #define YANU_CONTROL_IE_TRDY (1<<5) /* ie interrupt on tranmitter ready */ /* control bits */ #define YANU_CONTROL_BITS_POS (6) /* bits number pos */ #define YANU_CONTROL_BITS (1<<YANU_CONTROL_BITS_POS) /* number of rx/tx bits per word. 3 bit unsigned integer */ #define YANU_CONTROL_BITS_N (3) /* ... its bit filed length */ #define YANU_CONTROL_PARENA (1<<9) /* enable parity bit transmission/reception */ #define YANU_CONTROL_PAREVEN (1<<10) /* parity even */ #define YANU_CONTROL_STOPS (1<<11) /* number of stop bits */ #define YANU_CONTROL_HHENA (1<<12) /* Harware Handshake enable... */ #define YANU_CONTROL_FORCEBRK (1<<13) /* if set than txd = active (0) */ /* tuning part */ #define YANU_CONTROL_RDYDLY (1<<14) /* delay from "first" before setting rrdy (in bit) */ #define YANU_CONTROL_RDYDLY_N (8) /* ... its bit filed length */ #define YANU_CONTROL_TXTHR (1<<22) /* tx interrupt threshold: the trdy set if txfifo_chars<= txthr (chars) */ #define YANU_CONTROL_TXTHR_N (4) /* ... its bit field length */ #define YANU_BAUD_OFFSET (8) /* baud register offset */ #define YANU_BAUDM (1<<0) /* baud mantissa lsb */ #define YANU_BAUDM_N (12) /* ...its bit filed length */ #define YANU_BAUDE (1<<12) /* baud exponent lsb */ #define YANU_BAUDE_N (4) /* ...its bit field length */ #define YANU_ACTION_OFFSET (12) /* action register... write only */ #define YANU_ACTION_RRRDY (1<<0) /* reset rrdy */ #define YANU_ACTION_ROE (1<<1) /* reset oe */ #define YANU_ACTION_RBRK (1<<2) /* reset brk */ #define YANU_ACTION_RFE (1<<3) /* reset fe */ #define YANU_ACTION_RPE (1<<4) /* reset pe */ #define YANU_ACTION_SRRDY (1<<5) /* set rrdy */ #define YANU_ACTION_SOE (1<<6) /* set oe */ #define YANU_ACTION_SBRK (1<<7) /* set brk */ #define YANU_ACTION_SFE (1<<8) /* set fe */ #define YANU_ACTION_SPE (1<<9) /* set pe */ #define YANU_ACTION_RFIFO_PULL (1<<10) /* pull a char from rx fifo we MUST do it before taking a char */ #define YANU_ACTION_RFIFO_CLEAR (1<<11) /* clear rx fifo */ #define YANU_ACTION_TFIFO_CLEAR (1<<12) /* clear tx fifo */ #define YANU_ACTION_RTRDY (1<<13) /* clear trdy */ #define YANU_ACTION_STRDY (1<<14) /* set trdy */ #define YANU_STATUS_OFFSET (16) #define YANU_STATUS_RRDY (1<<0) /* rxrdy flag */ #define YANU_STATUS_TRDY (1<<1) /* txrdy flag */ #define YANU_STATUS_OE (1<<2) /* rx overrun error */ #define YANU_STATUS_BRK (1<<3) /* rx break detect flag */ #define YANU_STATUS_FE (1<<4) /* rx framing error flag */ #define YANU_STATUS_PE (1<<5) /* rx parity erro flag */ #define YANU_RFIFO_CHARS_POS (6) #define YANU_RFIFO_CHARS (1<<RFIFO_CHAR_POS) /* number of chars into rx fifo */ #define YANU_RFIFO_CHARS_N (5) /* ...its bit field length: 32 chars */ #define YANU_TFIFO_CHARS_POS (11) #define YANU_TFIFO_CHARS (1<<TFIFO_CHAR_POS) /* number of chars into tx fifo */ #define YANU_TFIFO_CHARS_N (5) /* ...its bit field length: 32 chars */ typedef volatile struct { volatile unsigned data; volatile unsigned control; /* control register (RW) 32-bit */ volatile unsigned baud; /* baud/prescaler register (RW) 32-bit */ volatile unsigned action; /* action register (W) 32-bit */ volatile unsigned status; /* status register (R) 32-bit */ volatile unsigned magic; /* magic register (R) 32-bit */ } yanu_uart_t; static yanu_uart_t *uart = (yanu_uart_t *)CONFIG_SYS_NIOS_CONSOLE; static void oc_serial_setbrg(void) { int n, k; const unsigned max_uns = 0xFFFFFFFF; unsigned best_n, best_m, baud; unsigned baudrate; #if defined(CONFIG_SYS_NIOS_FIXEDBAUD) /* Everything's already setup for fixed-baud PTF assignment */ baudrate = CONFIG_BAUDRATE; #else baudrate = gd->baudrate; #endif /* 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)) >= baudrate) { best_n = n; break; } } for (k = 0;; k++) { if (baudrate <= (max_uns >> (15+n-k))) break; } best_m = (baudrate * (1 << (15 + n - k))) / ((unsigned)CONFIG_SYS_CLK_FREQ >> k); baud = best_m + best_n * YANU_BAUDE; writel(baud, &uart->baud); return; } static int oc_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(action, &uart->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(control, &uart->control); /* to set baud rate */ serial_setbrg(); return (0); } /*----------------------------------------------------------------------- * YANU CONSOLE *---------------------------------------------------------------------*/ static void oc_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((unsigned char)c, &uart->data); } static int oc_serial_tstc(void) { unsigned status ; status = readl(&uart->status); return (((status >> YANU_RFIFO_CHARS_POS) & ((1 << YANU_RFIFO_CHARS_N) - 1)) > 0); } static int oc_serial_getc(void) { while (serial_tstc() == 0) WATCHDOG_RESET (); /* first we pull the char */ writel(YANU_ACTION_RFIFO_PULL, &uart->action); return(readl(&uart->data) & YANU_DATA_CHAR_MASK); } static struct serial_device oc_serial_drv = { .name = "oc_serial", .start = oc_serial_init, .stop = NULL, .setbrg = oc_serial_setbrg, .putc = oc_serial_putc, .puts = default_serial_puts, .getc = oc_serial_getc, .tstc = oc_serial_tstc, }; void oc_serial_initialize(void) { serial_register(&oc_serial_drv); } __weak struct serial_device *default_serial_console(void) { return &oc_serial_drv; }