drivers/mtd/maps/autcpu12-nvram.c

   1 /*
   2  * NV-RAM memory access on autcpu12
   3  * (C) 2002 Thomas Gleixner (gleixner@autronix.de)
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kernel.h>
  24 #include <linux/ioport.h>
  25 #include <linux/init.h>
  26 #include <asm/io.h>
  27 #include <asm/sizes.h>
  28 #include <mach/hardware.h>
  29 #include <mach/autcpu12.h>
  30 #include <linux/mtd/mtd.h>
  31 #include <linux/mtd/map.h>
  32 #include <linux/mtd/partitions.h>
  33
  34
  35 static struct mtd_info *sram_mtd;
  36
  37 struct map_info autcpu12_sram_map = {
  38         .name = "SRAM",
  39         .size = 32768,
  40         .bankwidth = 4,
  41         .phys = 0x12000000,
  42 };
  43
  44 static int __init init_autcpu12_sram (void)
  45 {
  46         map_word tmp, save0, save1;
  47         int err;
  48
  49         autcpu12_sram_map.virt = ioremap(0x12000000, SZ_128K);
  50         if (!autcpu12_sram_map.virt) {
  51                 printk("Failed to ioremap autcpu12 NV-RAM space\n");
  52                 err = -EIO;
  53                 goto out;
  54         }
  55         simple_map_init(&autcpu12_sram_map);
  56
  57         /*
  58          * Check for 32K/128K
  59          * read ofs 0
  60          * read ofs 0x10000
  61          * Write complement to ofs 0x100000
  62          * Read and check result on ofs 0x0
  63          * Restore contents
  64          */
  65         save0 = map_read(&autcpu12_sram_map, 0);
  66         save1 = map_read(&autcpu12_sram_map, 0x10000);
  67         tmp.x[0] = ~save0.x[0];
  68         map_write(&autcpu12_sram_map, tmp, 0x10000);
  69         /* if we find this pattern on 0x0, we have 32K size
  70          * restore contents and exit
  71          */
  72         tmp = map_read(&autcpu12_sram_map, 0);
  73         if (!map_word_equal(&autcpu12_sram_map, tmp, save0)) {
  74                 map_write(&autcpu12_sram_map, save0, 0x0);
  75                 goto map;
  76         }
  77         /* We have a 128K found, restore 0x10000 and set size
  78          * to 128K
  79          */
  80         map_write(&autcpu12_sram_map, save1, 0x10000);
  81         autcpu12_sram_map.size = SZ_128K;
  82
  83 map:
  84         sram_mtd = do_map_probe("map_ram", &autcpu12_sram_map);
  85         if (!sram_mtd) {
  86                 printk("NV-RAM probe failed\n");
  87                 err = -ENXIO;
  88                 goto out_ioremap;
  89         }
  90
  91         sram_mtd->owner = THIS_MODULE;
  92         sram_mtd->erasesize = 16;
  93
  94         if (mtd_device_register(sram_mtd, NULL, 0)) {
  95                 printk("NV-RAM device addition failed\n");
  96                 err = -ENOMEM;
  97                 goto out_probe;
  98         }
  99
 100         printk("NV-RAM device size %ldKiB registered on AUTCPU12\n",autcpu12_sram_map.size/SZ_1K);
 101
 102         return 0;
 103
 104 out_probe:
 105         map_destroy(sram_mtd);
 106         sram_mtd = 0;
 107
 108 out_ioremap:
 109         iounmap((void *)autcpu12_sram_map.virt);
 110 out:
 111         return err;
 112 }
 113
 114 static void __exit cleanup_autcpu12_maps(void)
 115 {
 116         if (sram_mtd) {
 117                 mtd_device_unregister(sram_mtd);
 118                 map_destroy(sram_mtd);
 119                 iounmap((void *)autcpu12_sram_map.virt);
 120         }
 121 }
 122
 123 module_init(init_autcpu12_sram);
 124 module_exit(cleanup_autcpu12_maps);
 125
 126 MODULE_AUTHOR("Thomas Gleixner");
 127 MODULE_DESCRIPTION("autcpu12 NV-RAM map driver");
 128 MODULE_LICENSE("GPL");