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, unsigned long start, unsigned long 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 ustrtoul(const char *cp, char **endp, unsigned int base) 145 { 146 unsigned long result = simple_strtoul(cp, endp, base); 147 148 switch (**endp) { 149 case 'G': 150 result *= 1024; 151 case 'M': 152 result *= 1024; 153 case 'k': 154 result *= 1024; 155 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ 156 if ((*endp)[1] == 'i') 157 (*endp) += 2; 158 } 159 return result; 160 } 161 162 static int parse_num32(uint32_t *num32, const char *token) 163 { 164 char *endp; 165 unsigned long n; 166 167 n = ustrtoul(token, &endp, 0); 168 if (*endp) 169 return -EINVAL; 170 171 *num32 = n; 172 return 0; 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 /* 209 * This shall contain the module parameter if any. It is of the form: 210 * - phram=<device>,<address>,<size> for module case 211 * - phram.phram=<device>,<address>,<size> for built-in case 212 * We leave 64 bytes for the device name, 12 for the address and 12 for the 213 * size. 214 * Example: phram.phram=rootfs,0xa0000000,512Mi 215 */ 216 static __initdata char phram_paramline[64+12+12]; 217 218 static int __init phram_setup(const char *val) 219 { 220 char buf[64+12+12], *str = buf; 221 char *token[3]; 222 char *name; 223 uint32_t start; 224 uint32_t len; 225 int i, ret; 226 227 if (strnlen(val, sizeof(buf)) >= sizeof(buf)) 228 parse_err("parameter too long\n"); 229 230 strcpy(str, val); 231 kill_final_newline(str); 232 233 for (i=0; i<3; i++) 234 token[i] = strsep(&str, ","); 235 236 if (str) 237 parse_err("too many arguments\n"); 238 239 if (!token[2]) 240 parse_err("not enough arguments\n"); 241 242 ret = parse_name(&name, token[0]); 243 if (ret) 244 return ret; 245 246 ret = parse_num32(&start, token[1]); 247 if (ret) { 248 kfree(name); 249 parse_err("illegal start address\n"); 250 } 251 252 ret = parse_num32(&len, token[2]); 253 if (ret) { 254 kfree(name); 255 parse_err("illegal device length\n"); 256 } 257 258 ret = register_device(name, start, len); 259 if (!ret) 260 pr_info("%s device: %#x at %#x\n", name, len, start); 261 else 262 kfree(name); 263 264 return ret; 265 } 266 267 static int __init phram_param_call(const char *val, struct kernel_param *kp) 268 { 269 /* 270 * This function is always called before 'init_phram()', whether 271 * built-in or module. 272 */ 273 if (strlen(val) >= sizeof(phram_paramline)) 274 return -ENOSPC; 275 strcpy(phram_paramline, val); 276 277 return 0; 278 } 279 280 module_param_call(phram, phram_param_call, NULL, NULL, 000); 281 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\""); 282 283 284 static int __init init_phram(void) 285 { 286 if (phram_paramline[0]) 287 return phram_setup(phram_paramline); 288 289 return 0; 290 } 291 292 static void __exit cleanup_phram(void) 293 { 294 unregister_devices(); 295 } 296 297 module_init(init_phram); 298 module_exit(cleanup_phram); 299 300 MODULE_LICENSE("GPL"); 301 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>"); 302 MODULE_DESCRIPTION("MTD driver for physical RAM"); 303