1 /** 2 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de> 3 * Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de> 4 * 5 * Usage: 6 * 7 * one commend line parameter per device, each in the form: 8 * phram=<name>,<start>,<len> 9 * <name> may be up to 63 characters. 10 * <start> and <len> can be octal, decimal or hexadecimal. If followed 11 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or 12 * gigabytes. 13 * 14 * Example: 15 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi 16 */ 17 18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 19 20 #include <linux/io.h> 21 #include <linux/init.h> 22 #include <linux/kernel.h> 23 #include <linux/list.h> 24 #include <linux/module.h> 25 #include <linux/moduleparam.h> 26 #include <linux/slab.h> 27 #include <linux/mtd/mtd.h> 28 29 struct phram_mtd_list { 30 struct mtd_info mtd; 31 struct list_head list; 32 }; 33 34 static LIST_HEAD(phram_list); 35 36 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr) 37 { 38 u_char *start = mtd->priv; 39 40 memset(start + instr->addr, 0xff, instr->len); 41 42 /* 43 * This'll catch a few races. Free the thing before returning :) 44 * I don't feel at all ashamed. This kind of thing is possible anyway 45 * with flash, but unlikely. 46 */ 47 instr->state = MTD_ERASE_DONE; 48 mtd_erase_callback(instr); 49 return 0; 50 } 51 52 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len, 53 size_t *retlen, void **virt, resource_size_t *phys) 54 { 55 *virt = mtd->priv + from; 56 *retlen = len; 57 return 0; 58 } 59 60 static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 61 { 62 return 0; 63 } 64 65 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len, 66 size_t *retlen, u_char *buf) 67 { 68 u_char *start = mtd->priv; 69 70 memcpy(buf, start + from, len); 71 *retlen = len; 72 return 0; 73 } 74 75 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len, 76 size_t *retlen, const u_char *buf) 77 { 78 u_char *start = mtd->priv; 79 80 memcpy(start + to, buf, len); 81 *retlen = len; 82 return 0; 83 } 84 85 static void unregister_devices(void) 86 { 87 struct phram_mtd_list *this, *safe; 88 89 list_for_each_entry_safe(this, safe, &phram_list, list) { 90 mtd_device_unregister(&this->mtd); 91 iounmap(this->mtd.priv); 92 kfree(this->mtd.name); 93 kfree(this); 94 } 95 } 96 97 static int register_device(char *name, phys_addr_t start, size_t len) 98 { 99 struct phram_mtd_list *new; 100 int ret = -ENOMEM; 101 102 new = kzalloc(sizeof(*new), GFP_KERNEL); 103 if (!new) 104 goto out0; 105 106 ret = -EIO; 107 new->mtd.priv = ioremap(start, len); 108 if (!new->mtd.priv) { 109 pr_err("ioremap failed\n"); 110 goto out1; 111 } 112 113 114 new->mtd.name = name; 115 new->mtd.size = len; 116 new->mtd.flags = MTD_CAP_RAM; 117 new->mtd._erase = phram_erase; 118 new->mtd._point = phram_point; 119 new->mtd._unpoint = phram_unpoint; 120 new->mtd._read = phram_read; 121 new->mtd._write = phram_write; 122 new->mtd.owner = THIS_MODULE; 123 new->mtd.type = MTD_RAM; 124 new->mtd.erasesize = PAGE_SIZE; 125 new->mtd.writesize = 1; 126 127 ret = -EAGAIN; 128 if (mtd_device_register(&new->mtd, NULL, 0)) { 129 pr_err("Failed to register new device\n"); 130 goto out2; 131 } 132 133 list_add_tail(&new->list, &phram_list); 134 return 0; 135 136 out2: 137 iounmap(new->mtd.priv); 138 out1: 139 kfree(new); 140 out0: 141 return ret; 142 } 143 144 static int parse_num64(uint64_t *num64, char *token) 145 { 146 size_t len; 147 int shift = 0; 148 int ret; 149 150 len = strlen(token); 151 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ 152 if (len > 2) { 153 if (token[len - 1] == 'i') { 154 switch (token[len - 2]) { 155 case 'G': 156 shift += 10; 157 case 'M': 158 shift += 10; 159 case 'k': 160 shift += 10; 161 token[len - 2] = 0; 162 break; 163 default: 164 return -EINVAL; 165 } 166 } 167 } 168 169 ret = kstrtou64(token, 0, num64); 170 *num64 <<= shift; 171 172 return ret; 173 } 174 175 static int parse_name(char **pname, const char *token) 176 { 177 size_t len; 178 char *name; 179 180 len = strlen(token) + 1; 181 if (len > 64) 182 return -ENOSPC; 183 184 name = kstrdup(token, GFP_KERNEL); 185 if (!name) 186 return -ENOMEM; 187 188 *pname = name; 189 return 0; 190 } 191 192 193 static inline void kill_final_newline(char *str) 194 { 195 char *newline = strrchr(str, '\n'); 196 197 if (newline && !newline[1]) 198 *newline = 0; 199 } 200 201 202 #define parse_err(fmt, args...) do { \ 203 pr_err(fmt , ## args); \ 204 return 1; \ 205 } while (0) 206 207 #ifndef MODULE 208 static int phram_init_called; 209 /* 210 * This shall contain the module parameter if any. It is of the form: 211 * - phram=<device>,<address>,<size> for module case 212 * - phram.phram=<device>,<address>,<size> for built-in case 213 * We leave 64 bytes for the device name, 20 for the address and 20 for the 214 * size. 215 * Example: phram.phram=rootfs,0xa0000000,512Mi 216 */ 217 static char phram_paramline[64 + 20 + 20]; 218 #endif 219 220 static int phram_setup(const char *val) 221 { 222 char buf[64 + 20 + 20], *str = buf; 223 char *token[3]; 224 char *name; 225 uint64_t start; 226 uint64_t len; 227 int i, ret; 228 229 if (strnlen(val, sizeof(buf)) >= sizeof(buf)) 230 parse_err("parameter too long\n"); 231 232 strcpy(str, val); 233 kill_final_newline(str); 234 235 for (i = 0; i < 3; i++) 236 token[i] = strsep(&str, ","); 237 238 if (str) 239 parse_err("too many arguments\n"); 240 241 if (!token[2]) 242 parse_err("not enough arguments\n"); 243 244 ret = parse_name(&name, token[0]); 245 if (ret) 246 return ret; 247 248 ret = parse_num64(&start, token[1]); 249 if (ret) { 250 kfree(name); 251 parse_err("illegal start address\n"); 252 } 253 254 ret = parse_num64(&len, token[2]); 255 if (ret) { 256 kfree(name); 257 parse_err("illegal device length\n"); 258 } 259 260 ret = register_device(name, start, len); 261 if (!ret) 262 pr_info("%s device: %#llx at %#llx\n", name, len, start); 263 else 264 kfree(name); 265 266 return ret; 267 } 268 269 static int phram_param_call(const char *val, struct kernel_param *kp) 270 { 271 #ifdef MODULE 272 return phram_setup(val); 273 #else 274 /* 275 * If more parameters are later passed in via 276 * /sys/module/phram/parameters/phram 277 * and init_phram() has already been called, 278 * we can parse the argument now. 279 */ 280 281 if (phram_init_called) 282 return phram_setup(val); 283 284 /* 285 * During early boot stage, we only save the parameters 286 * here. We must parse them later: if the param passed 287 * from kernel boot command line, phram_param_call() is 288 * called so early that it is not possible to resolve 289 * the device (even kmalloc() fails). Defer that work to 290 * phram_setup(). 291 */ 292 293 if (strlen(val) >= sizeof(phram_paramline)) 294 return -ENOSPC; 295 strcpy(phram_paramline, val); 296 297 return 0; 298 #endif 299 } 300 301 module_param_call(phram, phram_param_call, NULL, NULL, 000); 302 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\""); 303 304 305 static int __init init_phram(void) 306 { 307 int ret = 0; 308 309 #ifndef MODULE 310 if (phram_paramline[0]) 311 ret = phram_setup(phram_paramline); 312 phram_init_called = 1; 313 #endif 314 315 return ret; 316 } 317 318 static void __exit cleanup_phram(void) 319 { 320 unregister_devices(); 321 } 322 323 module_init(init_phram); 324 module_exit(cleanup_phram); 325 326 MODULE_LICENSE("GPL"); 327 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>"); 328 MODULE_DESCRIPTION("MTD driver for physical RAM"); 329