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) "phram: " 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 37 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr) 38 { 39 u_char *start = mtd->priv; 40 41 if (instr->addr + instr->len > mtd->size) 42 return -EINVAL; 43 44 memset(start + instr->addr, 0xff, instr->len); 45 46 /* This'll catch a few races. Free the thing before returning :) 47 * I don't feel at all ashamed. This kind of thing is possible anyway 48 * with flash, but unlikely. 49 */ 50 51 instr->state = MTD_ERASE_DONE; 52 53 mtd_erase_callback(instr); 54 55 return 0; 56 } 57 58 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len, 59 size_t *retlen, void **virt, resource_size_t *phys) 60 { 61 if (from + len > mtd->size) 62 return -EINVAL; 63 64 /* can we return a physical address with this driver? */ 65 if (phys) 66 return -EINVAL; 67 68 *virt = mtd->priv + from; 69 *retlen = len; 70 return 0; 71 } 72 73 static void phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 74 { 75 } 76 77 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len, 78 size_t *retlen, u_char *buf) 79 { 80 u_char *start = mtd->priv; 81 82 if (from >= mtd->size) 83 return -EINVAL; 84 85 if (len > mtd->size - from) 86 len = mtd->size - from; 87 88 memcpy(buf, start + from, len); 89 90 *retlen = len; 91 return 0; 92 } 93 94 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len, 95 size_t *retlen, const u_char *buf) 96 { 97 u_char *start = mtd->priv; 98 99 if (to >= mtd->size) 100 return -EINVAL; 101 102 if (len > mtd->size - to) 103 len = mtd->size - to; 104 105 memcpy(start + to, buf, len); 106 107 *retlen = len; 108 return 0; 109 } 110 111 112 113 static void unregister_devices(void) 114 { 115 struct phram_mtd_list *this, *safe; 116 117 list_for_each_entry_safe(this, safe, &phram_list, list) { 118 del_mtd_device(&this->mtd); 119 iounmap(this->mtd.priv); 120 kfree(this); 121 } 122 } 123 124 static int register_device(char *name, unsigned long start, unsigned long len) 125 { 126 struct phram_mtd_list *new; 127 int ret = -ENOMEM; 128 129 new = kzalloc(sizeof(*new), GFP_KERNEL); 130 if (!new) 131 goto out0; 132 133 ret = -EIO; 134 new->mtd.priv = ioremap(start, len); 135 if (!new->mtd.priv) { 136 pr_err("ioremap failed\n"); 137 goto out1; 138 } 139 140 141 new->mtd.name = name; 142 new->mtd.size = len; 143 new->mtd.flags = MTD_CAP_RAM; 144 new->mtd.erase = phram_erase; 145 new->mtd.point = phram_point; 146 new->mtd.unpoint = phram_unpoint; 147 new->mtd.read = phram_read; 148 new->mtd.write = phram_write; 149 new->mtd.owner = THIS_MODULE; 150 new->mtd.type = MTD_RAM; 151 new->mtd.erasesize = PAGE_SIZE; 152 new->mtd.writesize = 1; 153 154 ret = -EAGAIN; 155 if (add_mtd_device(&new->mtd)) { 156 pr_err("Failed to register new device\n"); 157 goto out2; 158 } 159 160 list_add_tail(&new->list, &phram_list); 161 return 0; 162 163 out2: 164 iounmap(new->mtd.priv); 165 out1: 166 kfree(new); 167 out0: 168 return ret; 169 } 170 171 static int ustrtoul(const char *cp, char **endp, unsigned int base) 172 { 173 unsigned long result = simple_strtoul(cp, endp, base); 174 175 switch (**endp) { 176 case 'G': 177 result *= 1024; 178 case 'M': 179 result *= 1024; 180 case 'k': 181 result *= 1024; 182 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ 183 if ((*endp)[1] == 'i') 184 (*endp) += 2; 185 } 186 return result; 187 } 188 189 static int parse_num32(uint32_t *num32, const char *token) 190 { 191 char *endp; 192 unsigned long n; 193 194 n = ustrtoul(token, &endp, 0); 195 if (*endp) 196 return -EINVAL; 197 198 *num32 = n; 199 return 0; 200 } 201 202 static int parse_name(char **pname, const char *token) 203 { 204 size_t len; 205 char *name; 206 207 len = strlen(token) + 1; 208 if (len > 64) 209 return -ENOSPC; 210 211 name = kmalloc(len, GFP_KERNEL); 212 if (!name) 213 return -ENOMEM; 214 215 strcpy(name, token); 216 217 *pname = name; 218 return 0; 219 } 220 221 222 static inline void kill_final_newline(char *str) 223 { 224 char *newline = strrchr(str, '\n'); 225 if (newline && !newline[1]) 226 *newline = 0; 227 } 228 229 230 #define parse_err(fmt, args...) do { \ 231 pr_err(fmt , ## args); \ 232 return 1; \ 233 } while (0) 234 235 static int phram_setup(const char *val, struct kernel_param *kp) 236 { 237 char buf[64+12+12], *str = buf; 238 char *token[3]; 239 char *name; 240 uint32_t start; 241 uint32_t len; 242 int i, ret; 243 244 if (strnlen(val, sizeof(buf)) >= sizeof(buf)) 245 parse_err("parameter too long\n"); 246 247 strcpy(str, val); 248 kill_final_newline(str); 249 250 for (i=0; i<3; i++) 251 token[i] = strsep(&str, ","); 252 253 if (str) 254 parse_err("too many arguments\n"); 255 256 if (!token[2]) 257 parse_err("not enough arguments\n"); 258 259 ret = parse_name(&name, token[0]); 260 if (ret) 261 return ret; 262 263 ret = parse_num32(&start, token[1]); 264 if (ret) { 265 kfree(name); 266 parse_err("illegal start address\n"); 267 } 268 269 ret = parse_num32(&len, token[2]); 270 if (ret) { 271 kfree(name); 272 parse_err("illegal device length\n"); 273 } 274 275 ret = register_device(name, start, len); 276 if (!ret) 277 pr_info("%s device: %#x at %#x\n", name, len, start); 278 279 return ret; 280 } 281 282 module_param_call(phram, phram_setup, NULL, NULL, 000); 283 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\""); 284 285 286 static int __init init_phram(void) 287 { 288 return 0; 289 } 290 291 static void __exit cleanup_phram(void) 292 { 293 unregister_devices(); 294 } 295 296 module_init(init_phram); 297 module_exit(cleanup_phram); 298 299 MODULE_LICENSE("GPL"); 300 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>"); 301 MODULE_DESCRIPTION("MTD driver for physical RAM"); 302