drivers/mtd/maps/sc520cdp.c

   1 /* sc520cdp.c -- MTD map driver for AMD SC520 Customer Development Platform
   2  *
   3  * Copyright (C) 2001 Sysgo Real-Time Solutions GmbH
   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  * $Id: sc520cdp.c,v 1.23 2005/11/17 08:20:27 dwmw2 Exp $
  20  *
  21  *
  22  * The SC520CDP is an evaluation board for the Elan SC520 processor available
  23  * from AMD. It has two banks of 32-bit Flash ROM, each 8 Megabytes in size,
  24  * and up to 512 KiB of 8-bit DIL Flash ROM.
  25  * For details see http://www.amd.com/products/epd/desiging/evalboards/18.elansc520/520_cdp_brief/index.html
  26  */
  27
  28 #include <linux/module.h>
  29 #include <linux/types.h>
  30 #include <linux/kernel.h>
  31 #include <linux/init.h>
  32 #include <asm/io.h>
  33 #include <linux/mtd/mtd.h>
  34 #include <linux/mtd/map.h>
  35 #include <linux/mtd/concat.h>
  36
  37 /*
  38 ** The Embedded Systems BIOS decodes the first FLASH starting at
  39 ** 0x8400000. This is a *terrible* place for it because accessing
  40 ** the flash at this location causes the A22 address line to be high
  41 ** (that's what 0x8400000 binary's ought to be). But this is the highest
  42 ** order address line on the raw flash devices themselves!!
  43 ** This causes the top HALF of the flash to be accessed first. Beyond
  44 ** the physical limits of the flash, the flash chip aliases over (to
  45 ** 0x880000 which causes the bottom half to be accessed. This splits the
  46 ** flash into two and inverts it! If you then try to access this from another
  47 ** program that does NOT do this insanity, then you *will* access the
  48 ** first half of the flash, but not find what you expect there. That
  49 ** stuff is in the *second* half! Similarly, the address used by the
  50 ** BIOS for the second FLASH bank is also quite a bad choice.
  51 ** If REPROGRAM_PAR is defined below (the default), then this driver will
  52 ** choose more useful addresses for the FLASH banks by reprogramming the
  53 ** responsible PARxx registers in the SC520's MMCR region. This will
  54 ** cause the settings to be incompatible with the BIOS's settings, which
  55 ** shouldn't be a problem since you are running Linux, (i.e. the BIOS is
  56 ** not much use anyway). However, if you need to be compatible with
  57 ** the BIOS for some reason, just undefine REPROGRAM_PAR.
  58 */
  59 #define REPROGRAM_PAR
  60
  61
  62
  63 #ifdef REPROGRAM_PAR
  64
  65 /* These are the addresses we want.. */
  66 #define WINDOW_ADDR_0   0x08800000
  67 #define WINDOW_ADDR_1   0x09000000
  68 #define WINDOW_ADDR_2   0x09800000
  69
  70 /* .. and these are the addresses the BIOS gives us */
  71 #define WINDOW_ADDR_0_BIOS      0x08400000
  72 #define WINDOW_ADDR_1_BIOS      0x08c00000
  73 #define WINDOW_ADDR_2_BIOS      0x09400000
  74
  75 #else
  76
  77 #define WINDOW_ADDR_0   0x08400000
  78 #define WINDOW_ADDR_1   0x08C00000
  79 #define WINDOW_ADDR_2   0x09400000
  80
  81 #endif
  82
  83 #define WINDOW_SIZE_0   0x00800000
  84 #define WINDOW_SIZE_1   0x00800000
  85 #define WINDOW_SIZE_2   0x00080000
  86
  87
  88 static struct map_info sc520cdp_map[] = {
  89         {
  90                 .name = "SC520CDP Flash Bank #0",
  91                 .size = WINDOW_SIZE_0,
  92                 .bankwidth = 4,
  93                 .phys = WINDOW_ADDR_0
  94         },
  95         {
  96                 .name = "SC520CDP Flash Bank #1",
  97                 .size = WINDOW_SIZE_1,
  98                 .bankwidth = 4,
  99                 .phys = WINDOW_ADDR_1
 100         },
 101         {
 102                 .name = "SC520CDP DIL Flash",
 103                 .size = WINDOW_SIZE_2,
 104                 .bankwidth = 1,
 105                 .phys = WINDOW_ADDR_2
 106         },
 107 };
 108
 109 #define NUM_FLASH_BANKS ARRAY_SIZE(sc520cdp_map)
 110
 111 static struct mtd_info *mymtd[NUM_FLASH_BANKS];
 112 static struct mtd_info *merged_mtd;
 113
 114 #ifdef REPROGRAM_PAR
 115
 116 /*
 117 ** The SC520 MMCR (memory mapped control register) region resides
 118 ** at 0xFFFEF000. The 16 Programmable Address Region (PAR) registers
 119 ** are at offset 0x88 in the MMCR:
 120 */
 121 #define SC520_MMCR_BASE         0xFFFEF000
 122 #define SC520_MMCR_EXTENT       0x1000
 123 #define SC520_PAR(x)            ((0x88/sizeof(unsigned long)) + (x))
 124 #define NUM_SC520_PAR           16      /* total number of PAR registers */
 125
 126 /*
 127 ** The highest three bits in a PAR register determine what target
 128 ** device is controlled by this PAR. Here, only ROMCS? and BOOTCS
 129 ** devices are of interest.
 130 */
 131 #define SC520_PAR_BOOTCS        (0x4<<29)
 132 #define SC520_PAR_ROMCS0        (0x5<<29)
 133 #define SC520_PAR_ROMCS1        (0x6<<29)
 134 #define SC520_PAR_TRGDEV        (0x7<<29)
 135
 136 /*
 137 ** Bits 28 thru 26 determine some attributes for the
 138 ** region controlled by the PAR. (We only use non-cacheable)
 139 */
 140 #define SC520_PAR_WRPROT        (1<<26) /* write protected       */
 141 #define SC520_PAR_NOCACHE       (1<<27) /* non-cacheable         */
 142 #define SC520_PAR_NOEXEC        (1<<28) /* code execution denied */
 143
 144
 145 /*
 146 ** Bit 25 determines the granularity: 4K or 64K
 147 */
 148 #define SC520_PAR_PG_SIZ4       (0<<25)
 149 #define SC520_PAR_PG_SIZ64      (1<<25)
 150
 151 /*
 152 ** Build a value to be written into a PAR register.
 153 ** We only need ROM entries, 64K page size:
 154 */
 155 #define SC520_PAR_ENTRY(trgdev, address, size) \
 156         ((trgdev) | SC520_PAR_NOCACHE | SC520_PAR_PG_SIZ64 | \
 157         (address) >> 16 | (((size) >> 16) - 1) << 14)
 158
 159 struct sc520_par_table
 160 {
 161         unsigned long trgdev;
 162         unsigned long new_par;
 163         unsigned long default_address;
 164 };
 165
 166 static const struct sc520_par_table par_table[NUM_FLASH_BANKS] =
 167 {
 168         {       /* Flash Bank #0: selected by ROMCS0 */
 169                 SC520_PAR_ROMCS0,
 170                 SC520_PAR_ENTRY(SC520_PAR_ROMCS0, WINDOW_ADDR_0, WINDOW_SIZE_0),
 171                 WINDOW_ADDR_0_BIOS
 172         },
 173         {       /* Flash Bank #1: selected by ROMCS1 */
 174                 SC520_PAR_ROMCS1,
 175                 SC520_PAR_ENTRY(SC520_PAR_ROMCS1, WINDOW_ADDR_1, WINDOW_SIZE_1),
 176                 WINDOW_ADDR_1_BIOS
 177         },
 178         {       /* DIL (BIOS) Flash: selected by BOOTCS */
 179                 SC520_PAR_BOOTCS,
 180                 SC520_PAR_ENTRY(SC520_PAR_BOOTCS, WINDOW_ADDR_2, WINDOW_SIZE_2),
 181                 WINDOW_ADDR_2_BIOS
 182         }
 183 };
 184
 185
 186 static void sc520cdp_setup_par(void)
 187 {
 188         volatile unsigned long __iomem *mmcr;
 189         unsigned long mmcr_val;
 190         int i, j;
 191
 192         /* map in SC520's MMCR area */
 193         mmcr = ioremap_nocache(SC520_MMCR_BASE, SC520_MMCR_EXTENT);
 194         if(!mmcr) { /* ioremap_nocache failed: skip the PAR reprogramming */
 195                 /* force physical address fields to BIOS defaults: */
 196                 for(i = 0; i < NUM_FLASH_BANKS; i++)
 197                         sc520cdp_map[i].phys = par_table[i].default_address;
 198                 return;
 199         }
 200
 201         /*
 202         ** Find the PARxx registers that are reponsible for activating
 203         ** ROMCS0, ROMCS1 and BOOTCS. Reprogram each of these with a
 204         ** new value from the table.
 205         */
 206         for(i = 0; i < NUM_FLASH_BANKS; i++) {          /* for each par_table entry  */
 207                 for(j = 0; j < NUM_SC520_PAR; j++) {    /* for each PAR register     */
 208                         mmcr_val = mmcr[SC520_PAR(j)];
 209                         /* if target device field matches, reprogram the PAR */
 210                         if((mmcr_val & SC520_PAR_TRGDEV) == par_table[i].trgdev)
 211                         {
 212                                 mmcr[SC520_PAR(j)] = par_table[i].new_par;
 213                                 break;
 214                         }
 215                 }
 216                 if(j == NUM_SC520_PAR)
 217                 {       /* no matching PAR found: try default BIOS address */
 218                         printk(KERN_NOTICE "Could not find PAR responsible for %s\n",
 219                                 sc520cdp_map[i].name);
 220                         printk(KERN_NOTICE "Trying default address 0x%lx\n",
 221                                 par_table[i].default_address);
 222                         sc520cdp_map[i].phys = par_table[i].default_address;
 223                 }
 224         }
 225         iounmap(mmcr);
 226 }
 227 #endif
 228
 229
 230 static int __init init_sc520cdp(void)
 231 {
 232         int i, devices_found = 0;
 233
 234 #ifdef REPROGRAM_PAR
 235         /* reprogram PAR registers so flash appears at the desired addresses */
 236         sc520cdp_setup_par();
 237 #endif
 238
 239         for (i = 0; i < NUM_FLASH_BANKS; i++) {
 240                 printk(KERN_NOTICE "SC520 CDP flash device: 0x%lx at 0x%lx\n",
 241                        sc520cdp_map[i].size, sc520cdp_map[i].phys);
 242
 243                 sc520cdp_map[i].virt = ioremap_nocache(sc520cdp_map[i].phys, sc520cdp_map[i].size);
 244
 245                 if (!sc520cdp_map[i].virt) {
 246                         printk("Failed to ioremap_nocache\n");
 247                         return -EIO;
 248                 }
 249
 250                 simple_map_init(&sc520cdp_map[i]);
 251
 252                 mymtd[i] = do_map_probe("cfi_probe", &sc520cdp_map[i]);
 253                 if(!mymtd[i])
 254                         mymtd[i] = do_map_probe("jedec_probe", &sc520cdp_map[i]);
 255                 if(!mymtd[i])
 256                         mymtd[i] = do_map_probe("map_rom", &sc520cdp_map[i]);
 257
 258                 if (mymtd[i]) {
 259                         mymtd[i]->owner = THIS_MODULE;
 260                         ++devices_found;
 261                 }
 262                 else {
 263                         iounmap(sc520cdp_map[i].virt);
 264                 }
 265         }
 266         if(devices_found >= 2) {
 267                 /* Combine the two flash banks into a single MTD device & register it: */
 268                 merged_mtd = mtd_concat_create(mymtd, 2, "SC520CDP Flash Banks #0 and #1");
 269                 if(merged_mtd)
 270                         add_mtd_device(merged_mtd);
 271         }
 272         if(devices_found == 3) /* register the third (DIL-Flash) device */
 273                 add_mtd_device(mymtd[2]);
 274         return(devices_found ? 0 : -ENXIO);
 275 }
 276
 277 static void __exit cleanup_sc520cdp(void)
 278 {
 279         int i;
 280
 281         if (merged_mtd) {
 282                 del_mtd_device(merged_mtd);
 283                 mtd_concat_destroy(merged_mtd);
 284         }
 285         if (mymtd[2])
 286                 del_mtd_device(mymtd[2]);
 287
 288         for (i = 0; i < NUM_FLASH_BANKS; i++) {
 289                 if (mymtd[i])
 290                         map_destroy(mymtd[i]);
 291                 if (sc520cdp_map[i].virt) {
 292                         iounmap(sc520cdp_map[i].virt);
 293                         sc520cdp_map[i].virt = NULL;
 294                 }
 295         }
 296 }
 297
 298 module_init(init_sc520cdp);
 299 module_exit(cleanup_sc520cdp);
 300
 301 MODULE_LICENSE("GPL");
 302 MODULE_AUTHOR("Sysgo Real-Time Solutions GmbH");
 303 MODULE_DESCRIPTION("MTD map driver for AMD SC520 Customer Development Platform");