[U-Boot] PATCH - Added support to YANU Nios2 uart

[Renato Andreola <renato.andreola@imagos.it>]

 From 6e15ffc680ca75d5bd3a01fc9010c34637c6ab32 Mon Sep 17 00:00:00 2001
From: Renato Andreola <renato.andreola@imagos.it>
Date: Thu, 6 Aug 2009 12:28:51 +0200
Subject: [PATCH] Yanu Support for U-Boot

with this patch YANU uart support will be added to u-boot.
Remember to modify properly your board files for defining physical 
address etc etc

Signed-off-by: Renato Andreola renato.andreola at imagos.it
---
  cpu/nios2/serial.c   |  158 
+++++++++++++++++++++++++++++++++++++++++++++++++-
  include/nios2-yanu.h |  119 +++++++++++++++++++++++++++++++++++++
  2 files changed, 276 insertions(+), 1 deletions(-)
  create mode 100644 include/nios2-yanu.h

diff --git a/cpu/nios2/serial.c b/cpu/nios2/serial.c
index 8bbb803..e77b2c6 100644
--- a/cpu/nios2/serial.c
+++ b/cpu/nios2/serial.c
@@ -26,6 +26,8 @@
  #include <watchdog.h>
  #include <asm/io.h>
  #include <nios2-io.h>
+#include <nios2-yanu.h>
+

  DECLARE_GLOBAL_DATA_PTR;

@@ -73,11 +75,165 @@ int serial_getc (void)
  	c = val & 0x0ff;
  	return (c);
  }
+/*------------------------------------------------------------------
+ * YANU Imagos serial port
+ *-----------------------------------------------------------------*/
+#elif defined(CONFIG_CONSOLE_YANU)
+
+static yanu_uart_t *uart = (yanu_uart_t *)CONFIG_SYS_NIOS_CONSOLE;
+
+#if defined(CONFIG_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)
+{
+	DECLARE_GLOBAL_DATA_PTR;
+	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 /* CFG_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);
+}
+
+#else

  /*------------------------------------------------------------------
   * UART the serial port
   *-----------------------------------------------------------------*/
-#else

  static nios_uart_t *uart = (nios_uart_t *) CONFIG_SYS_NIOS_CONSOLE;

diff --git a/include/nios2-yanu.h b/include/nios2-yanu.h
new file mode 100644
index 0000000..c560ced
--- /dev/null
+++ b/include/nios2-yanu.h
@@ -0,0 +1,119 @@
+/*
+ * (C) Copyright 2006, Imagos S.a.s <www.imagos.it>
+ * Cristiano Ghirardi <cristiano.ghirardi@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
+ */
+
+/*************************************************************************
+ * Altera NiosII YANU serial interface by Imagos
+ ************************************************************************/
+
+#ifndef __NIOS2_YANU_H__
+#define __NIOS2_YANU_H__
+
+#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 yanu_uart_t {
+	volatile unsigned data;
+/* control register (RW) 32-bit   */
+	volatile unsigned control;
+/* baud/prescaler register (RW) 32-bit */
+	volatile unsigned baud;
+/* action register (W) 32-bit */
+	volatile unsigned action;
+/* status register (R) 32-bit */
+	volatile unsigned status;
+/* magic register (R) 32-bit */
+	volatile unsigned magic;
+} yanu_uart_t;
+
+#endif
-- 
1.5.5