sead3-display.c

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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2012 MIPS Technologies, Inc.  All rights reserved.
 */
#include <linux/timer.h>
#include <linux/io.h>
#include <asm/mips-boards/generic.h>
#include <asm/mips-boards/prom.h>

static unsigned int display_count;
static unsigned int max_display_count;

#define LCD_DISPLAY_POS_BASE        0x1f000400
#define DISPLAY_LCDINSTRUCTION      (0*2)
#define DISPLAY_LCDDATA         (1*2)
#define DISPLAY_CPLDSTATUS      (2*2)
#define DISPLAY_CPLDDATA        (3*2)
#define LCD_SETDDRAM            0x80
#define LCD_IR_BF           0x80

const char display_string[] = "               LINUX ON SEAD3               ";

static void scroll_display_message(unsigned long data);
static DEFINE_TIMER(mips_scroll_timer, scroll_display_message, HZ, 0);

static void lcd_wait(unsigned int __iomem *display)
{
    /* Wait for CPLD state machine to become idle. */
    do { } while (__raw_readl(display + DISPLAY_CPLDSTATUS) & 1);

    do {
        __raw_readl(display + DISPLAY_LCDINSTRUCTION);

        /* Wait for CPLD state machine to become idle. */
        do { } while (__raw_readl(display + DISPLAY_CPLDSTATUS) & 1);
    } while (__raw_readl(display + DISPLAY_CPLDDATA) & LCD_IR_BF);
}

void mips_display_message(const char *str)
{
    static unsigned int __iomem *display;
    char ch;
    int i;

    if (unlikely(display == NULL))
        display = ioremap_nocache(LCD_DISPLAY_POS_BASE,
            (8 * sizeof(int)));

    for (i = 0; i < 16; i++) {
        if (*str)
            ch = *str++;
        else
            ch = ' ';
        lcd_wait(display);
        __raw_writel((LCD_SETDDRAM | i),
            (display + DISPLAY_LCDINSTRUCTION));
        lcd_wait(display);
        __raw_writel(ch, display + DISPLAY_LCDDATA);
    }
}

static void scroll_display_message(unsigned long data)
{
    mips_display_message(&display_string[display_count++]);
    if (display_count == max_display_count)
        display_count = 0;
    mod_timer(&mips_scroll_timer, jiffies + HZ);
}

void mips_scroll_message(void)
{
    del_timer_sync(&mips_scroll_timer);
    max_display_count = strlen(display_string) + 1 - 16;
    mod_timer(&mips_scroll_timer, jiffies + 1);
}