arch/mips/jz4740/prom.c

   1 /*
   2  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
   3  *  JZ4740 SoC prom code
   4  *
   5  *  This program is free software; you can redistribute it and/or modify it
   6  *  under  the terms of the GNU General  Public License as published by the
   7  *  Free Software Foundation;  either version 2 of the License, or (at your
   8  *  option) any later version.
   9  *
  10  *  You should have received a copy of the GNU General Public License along
  11  *  with this program; if not, write to the Free Software Foundation, Inc.,
  12  *  675 Mass Ave, Cambridge, MA 02139, USA.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/string.h>
  20
  21 #include <linux/serial_reg.h>
  22
  23 #include <asm/bootinfo.h>
  24 #include <asm/mach-jz4740/base.h>
  25
  26 static __init void jz4740_init_cmdline(int argc, char *argv[])
  27 {
  28         unsigned int count = COMMAND_LINE_SIZE - 1;
  29         int i;
  30         char *dst = &(arcs_cmdline[0]);
  31         char *src;
  32
  33         for (i = 1; i < argc && count; ++i) {
  34                 src = argv[i];
  35                 while (*src && count) {
  36                         *dst++ = *src++;
  37                         --count;
  38                 }
  39                 *dst++ = ' ';
  40         }
  41         if (i > 1)
  42                 --dst;
  43
  44         *dst = 0;
  45 }
  46
  47 void __init prom_init(void)
  48 {
  49         jz4740_init_cmdline((int)fw_arg0, (char **)fw_arg1);
  50         mips_machtype = MACH_INGENIC_JZ4740;
  51 }
  52
  53 void __init prom_free_prom_memory(void)
  54 {
  55 }
  56
  57 #define UART_REG(_reg) ((void __iomem *)CKSEG1ADDR(JZ4740_UART0_BASE_ADDR + (_reg << 2)))
  58
  59 void prom_putchar(char c)
  60 {
  61         uint8_t lsr;
  62
  63         do {
  64                 lsr = readb(UART_REG(UART_LSR));
  65         } while ((lsr & UART_LSR_TEMT) == 0);
  66
  67         writeb(c, UART_REG(UART_TX));
  68 }