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 (unsigned long long)sc520cdp_map[i].size, 242 (unsigned long long)sc520cdp_map[i].phys); 243 244 sc520cdp_map[i].virt = ioremap_nocache(sc520cdp_map[i].phys, sc520cdp_map[i].size); 245 246 if (!sc520cdp_map[i].virt) { 247 printk("Failed to ioremap_nocache\n"); 248 return -EIO; 249 } 250 251 simple_map_init(&sc520cdp_map[i]); 252 253 mymtd[i] = do_map_probe("cfi_probe", &sc520cdp_map[i]); 254 if(!mymtd[i]) 255 mymtd[i] = do_map_probe("jedec_probe", &sc520cdp_map[i]); 256 if(!mymtd[i]) 257 mymtd[i] = do_map_probe("map_rom", &sc520cdp_map[i]); 258 259 if (mymtd[i]) { 260 mymtd[i]->owner = THIS_MODULE; 261 ++devices_found; 262 } 263 else { 264 iounmap(sc520cdp_map[i].virt); 265 } 266 } 267 if(devices_found >= 2) { 268 /* Combine the two flash banks into a single MTD device & register it: */ 269 merged_mtd = mtd_concat_create(mymtd, 2, "SC520CDP Flash Banks #0 and #1"); 270 if(merged_mtd) 271 add_mtd_device(merged_mtd); 272 } 273 if(devices_found == 3) /* register the third (DIL-Flash) device */ 274 add_mtd_device(mymtd[2]); 275 return(devices_found ? 0 : -ENXIO); 276 } 277 278 static void __exit cleanup_sc520cdp(void) 279 { 280 int i; 281 282 if (merged_mtd) { 283 del_mtd_device(merged_mtd); 284 mtd_concat_destroy(merged_mtd); 285 } 286 if (mymtd[2]) 287 del_mtd_device(mymtd[2]); 288 289 for (i = 0; i < NUM_FLASH_BANKS; i++) { 290 if (mymtd[i]) 291 map_destroy(mymtd[i]); 292 if (sc520cdp_map[i].virt) { 293 iounmap(sc520cdp_map[i].virt); 294 sc520cdp_map[i].virt = NULL; 295 } 296 } 297 } 298 299 module_init(init_sc520cdp); 300 module_exit(cleanup_sc520cdp); 301 302 MODULE_LICENSE("GPL"); 303 MODULE_AUTHOR("Sysgo Real-Time Solutions GmbH"); 304 MODULE_DESCRIPTION("MTD map driver for AMD SC520 Customer Development Platform"); 305