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         int err, save0, save1;
  47
  48         autcpu12_sram_map.virt = ioremap(0x12000000, SZ_128K);
  49         if (!autcpu12_sram_map.virt) {
  50                 printk("Failed to ioremap autcpu12 NV-RAM space\n");
  51                 err = -EIO;
  52                 goto out;
  53         }
  54         simple_map_init(&autcpu_sram_map);
  55
  56         /*
  57          * Check for 32K/128K
  58          * read ofs 0
  59          * read ofs 0x10000
  60          * Write complement to ofs 0x100000
  61          * Read and check result on ofs 0x0
  62          * Restore contents
  63          */
  64         save0 = map_read32(&autcpu12_sram_map,0);
  65         save1 = map_read32(&autcpu12_sram_map,0x10000);
  66         map_write32(&autcpu12_sram_map,~save0,0x10000);
  67         /* if we find this pattern on 0x0, we have 32K size
  68          * restore contents and exit
  69          */
  70         if ( map_read32(&autcpu12_sram_map,0) != save0) {
  71                 map_write32(&autcpu12_sram_map,save0,0x0);
  72                 goto map;
  73         }
  74         /* We have a 128K found, restore 0x10000 and set size
  75          * to 128K
  76          */
  77         map_write32(&autcpu12_sram_map,save1,0x10000);
  78         autcpu12_sram_map.size = SZ_128K;
  79
  80 map:
  81         sram_mtd = do_map_probe("map_ram", &autcpu12_sram_map);
  82         if (!sram_mtd) {
  83                 printk("NV-RAM probe failed\n");
  84                 err = -ENXIO;
  85                 goto out_ioremap;
  86         }
  87
  88         sram_mtd->owner = THIS_MODULE;
  89         sram_mtd->erasesize = 16;
  90
  91         if (mtd_device_register(sram_mtd, NULL, 0)) {
  92                 printk("NV-RAM device addition failed\n");
  93                 err = -ENOMEM;
  94                 goto out_probe;
  95         }
  96
  97         printk("NV-RAM device size %ldKiB registered on AUTCPU12\n",autcpu12_sram_map.size/SZ_1K);
  98
  99         return 0;
 100
 101 out_probe:
 102         map_destroy(sram_mtd);
 103         sram_mtd = 0;
 104
 105 out_ioremap:
 106         iounmap((void *)autcpu12_sram_map.virt);
 107 out:
 108         return err;
 109 }
 110
 111 static void __exit cleanup_autcpu12_maps(void)
 112 {
 113         if (sram_mtd) {
 114                 mtd_device_unregister(sram_mtd);
 115                 map_destroy(sram_mtd);
 116                 iounmap((void *)autcpu12_sram_map.virt);
 117         }
 118 }
 119
 120 module_init(init_autcpu12_sram);
 121 module_exit(cleanup_autcpu12_maps);
 122
 123 MODULE_AUTHOR("Thomas Gleixner");
 124 MODULE_DESCRIPTION("autcpu12 NV-RAM map driver");
 125 MODULE_LICENSE("GPL");