arch/mips/mti-sead3/sead3-display.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2012 MIPS Technologies, Inc.  All rights reserved.
   7  */
   8 #include <linux/timer.h>
   9 #include <linux/io.h>
  10 #include <asm/mips-boards/generic.h>
  11 #include <asm/mips-boards/prom.h>
  12
  13 static unsigned int display_count;
  14 static unsigned int max_display_count;
  15
  16 #define LCD_DISPLAY_POS_BASE            0x1f000400
  17 #define DISPLAY_LCDINSTRUCTION          (0*2)
  18 #define DISPLAY_LCDDATA                 (1*2)
  19 #define DISPLAY_CPLDSTATUS              (2*2)
  20 #define DISPLAY_CPLDDATA                (3*2)
  21 #define LCD_SETDDRAM                    0x80
  22 #define LCD_IR_BF                       0x80
  23
  24 const char display_string[] = "               LINUX ON SEAD3               ";
  25
  26 static void scroll_display_message(unsigned long data);
  27 static DEFINE_TIMER(mips_scroll_timer, scroll_display_message, HZ, 0);
  28
  29 static void lcd_wait(unsigned int __iomem *display)
  30 {
  31         /* Wait for CPLD state machine to become idle. */
  32         do { } while (__raw_readl(display + DISPLAY_CPLDSTATUS) & 1);
  33
  34         do {
  35                 __raw_readl(display + DISPLAY_LCDINSTRUCTION);
  36
  37                 /* Wait for CPLD state machine to become idle. */
  38                 do { } while (__raw_readl(display + DISPLAY_CPLDSTATUS) & 1);
  39         } while (__raw_readl(display + DISPLAY_CPLDDATA) & LCD_IR_BF);
  40 }
  41
  42 void mips_display_message(const char *str)
  43 {
  44         static unsigned int __iomem *display;
  45         char ch;
  46         int i;
  47
  48         if (unlikely(display == NULL))
  49                 display = ioremap_nocache(LCD_DISPLAY_POS_BASE,
  50                         (8 * sizeof(int)));
  51
  52         for (i = 0; i < 16; i++) {
  53                 if (*str)
  54                         ch = *str++;
  55                 else
  56                         ch = ' ';
  57                 lcd_wait(display);
  58                 __raw_writel((LCD_SETDDRAM | i),
  59                         (display + DISPLAY_LCDINSTRUCTION));
  60                 lcd_wait(display);
  61                 __raw_writel(ch, display + DISPLAY_LCDDATA);
  62         }
  63 }
  64
  65 static void scroll_display_message(unsigned long data)
  66 {
  67         mips_display_message(&display_string[display_count++]);
  68         if (display_count == max_display_count)
  69                 display_count = 0;
  70         mod_timer(&mips_scroll_timer, jiffies + HZ);
  71 }
  72
  73 void mips_scroll_message(void)
  74 {
  75         del_timer_sync(&mips_scroll_timer);
  76         max_display_count = strlen(display_string) + 1 - 16;
  77         mod_timer(&mips_scroll_timer, jiffies + 1);
  78 }