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
  12 static unsigned int display_count;
  13 static unsigned int max_display_count;
  14
  15 #define LCD_DISPLAY_POS_BASE            0x1f000400
  16 #define DISPLAY_LCDINSTRUCTION          (0*2)
  17 #define DISPLAY_LCDDATA                 (1*2)
  18 #define DISPLAY_CPLDSTATUS              (2*2)
  19 #define DISPLAY_CPLDDATA                (3*2)
  20 #define LCD_SETDDRAM                    0x80
  21 #define LCD_IR_BF                       0x80
  22
  23 const char display_string[] = "               LINUX ON SEAD3               ";
  24
  25 static void scroll_display_message(unsigned long data);
  26 static DEFINE_TIMER(mips_scroll_timer, scroll_display_message, HZ, 0);
  27
  28 static void lcd_wait(unsigned int __iomem *display)
  29 {
  30         /* Wait for CPLD state machine to become idle. */
  31         do { } while (__raw_readl(display + DISPLAY_CPLDSTATUS) & 1);
  32
  33         do {
  34                 __raw_readl(display + DISPLAY_LCDINSTRUCTION);
  35
  36                 /* Wait for CPLD state machine to become idle. */
  37                 do { } while (__raw_readl(display + DISPLAY_CPLDSTATUS) & 1);
  38         } while (__raw_readl(display + DISPLAY_CPLDDATA) & LCD_IR_BF);
  39 }
  40
  41 void mips_display_message(const char *str)
  42 {
  43         static unsigned int __iomem *display;
  44         char ch;
  45         int i;
  46
  47         if (unlikely(display == NULL))
  48                 display = ioremap_nocache(LCD_DISPLAY_POS_BASE,
  49                         (8 * sizeof(int)));
  50
  51         for (i = 0; i < 16; i++) {
  52                 if (*str)
  53                         ch = *str++;
  54                 else
  55                         ch = ' ';
  56                 lcd_wait(display);
  57                 __raw_writel((LCD_SETDDRAM | i),
  58                         (display + DISPLAY_LCDINSTRUCTION));
  59                 lcd_wait(display);
  60                 __raw_writel(ch, display + DISPLAY_LCDDATA);
  61         }
  62 }
  63
  64 static void scroll_display_message(unsigned long data)
  65 {
  66         mips_display_message(&display_string[display_count++]);
  67         if (display_count == max_display_count)
  68                 display_count = 0;
  69         mod_timer(&mips_scroll_timer, jiffies + HZ);
  70 }
  71
  72 void mips_scroll_message(void)
  73 {
  74         del_timer_sync(&mips_scroll_timer);
  75         max_display_count = strlen(display_string) + 1 - 16;
  76         mod_timer(&mips_scroll_timer, jiffies + 1);
  77 }