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 <asm/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 = kmalloc(len, GFP_KERNEL); 185 if (!name) 186 return -ENOMEM; 187 188 strcpy(name, token); 189 190 *pname = name; 191 return 0; 192 } 193 194 195 static inline void kill_final_newline(char *str) 196 { 197 char *newline = strrchr(str, '\n'); 198 if (newline && !newline[1]) 199 *newline = 0; 200 } 201 202 203 #define parse_err(fmt, args...) do { \ 204 pr_err(fmt , ## args); \ 205 return 1; \ 206 } while (0) 207 208 #ifndef MODULE 209 static int phram_init_called; 210 /* 211 * This shall contain the module parameter if any. It is of the form: 212 * - phram=<device>,<address>,<size> for module case 213 * - phram.phram=<device>,<address>,<size> for built-in case 214 * We leave 64 bytes for the device name, 20 for the address and 20 for the 215 * size. 216 * Example: phram.phram=rootfs,0xa0000000,512Mi 217 */ 218 static char phram_paramline[64 + 20 + 20]; 219 #endif 220 221 static int phram_setup(const char *val) 222 { 223 char buf[64 + 20 + 20], *str = buf; 224 char *token[3]; 225 char *name; 226 uint64_t start; 227 uint64_t len; 228 int i, ret; 229 230 if (strnlen(val, sizeof(buf)) >= sizeof(buf)) 231 parse_err("parameter too long\n"); 232 233 strcpy(str, val); 234 kill_final_newline(str); 235 236 for (i=0; i<3; i++) 237 token[i] = strsep(&str, ","); 238 239 if (str) 240 parse_err("too many arguments\n"); 241 242 if (!token[2]) 243 parse_err("not enough arguments\n"); 244 245 ret = parse_name(&name, token[0]); 246 if (ret) 247 return ret; 248 249 ret = parse_num64(&start, token[1]); 250 if (ret) { 251 kfree(name); 252 parse_err("illegal start address\n"); 253 } 254 255 ret = parse_num64(&len, token[2]); 256 if (ret) { 257 kfree(name); 258 parse_err("illegal device length\n"); 259 } 260 261 ret = register_device(name, start, len); 262 if (!ret) 263 pr_info("%s device: %#llx at %#llx\n", name, len, start); 264 else 265 kfree(name); 266 267 return ret; 268 } 269 270 static int phram_param_call(const char *val, struct kernel_param *kp) 271 { 272 #ifdef MODULE 273 return phram_setup(val); 274 #else 275 /* 276 * If more parameters are later passed in via 277 * /sys/module/phram/parameters/phram 278 * and init_phram() has already been called, 279 * we can parse the argument now. 280 */ 281 282 if (phram_init_called) 283 return phram_setup(val); 284 285 /* 286 * During early boot stage, we only save the parameters 287 * here. We must parse them later: if the param passed 288 * from kernel boot command line, phram_param_call() is 289 * called so early that it is not possible to resolve 290 * the device (even kmalloc() fails). Defer that work to 291 * phram_setup(). 292 */ 293 294 if (strlen(val) >= sizeof(phram_paramline)) 295 return -ENOSPC; 296 strcpy(phram_paramline, val); 297 298 return 0; 299 #endif 300 } 301 302 module_param_call(phram, phram_param_call, NULL, NULL, 000); 303 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\""); 304 305 306 static int __init init_phram(void) 307 { 308 int ret = 0; 309 310 #ifndef MODULE 311 if (phram_paramline[0]) 312 ret = phram_setup(phram_paramline); 313 phram_init_called = 1; 314 #endif 315 316 return ret; 317 } 318 319 static void __exit cleanup_phram(void) 320 { 321 unregister_devices(); 322 } 323 324 module_init(init_phram); 325 module_exit(cleanup_phram); 326 327 MODULE_LICENSE("GPL"); 328 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>"); 329 MODULE_DESCRIPTION("MTD driver for physical RAM"); 330