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