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