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 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 responsible 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 = readl(&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 writel(par_table[i].new_par, &mmcr[SC520_PAR(j)]); 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 mtd_device_register(merged_mtd, NULL, 0); 270 } 271 if(devices_found == 3) /* register the third (DIL-Flash) device */ 272 mtd_device_register(mymtd[2], NULL, 0); 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 mtd_device_unregister(merged_mtd); 282 mtd_concat_destroy(merged_mtd); 283 } 284 if (mymtd[2]) 285 mtd_device_unregister(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"); 303