1 /** 2 * $Id: phram.c,v 1.16 2005/11/07 11:14:25 gleixner Exp $ 3 * 4 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de> 5 * Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de> 6 * 7 * Usage: 8 * 9 * one commend line parameter per device, each in the form: 10 * phram=<name>,<start>,<len> 11 * <name> may be up to 63 characters. 12 * <start> and <len> can be octal, decimal or hexadecimal. If followed 13 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or 14 * gigabytes. 15 * 16 * Example: 17 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi 18 */ 19 #include <asm/io.h> 20 #include <linux/init.h> 21 #include <linux/kernel.h> 22 #include <linux/list.h> 23 #include <linux/module.h> 24 #include <linux/moduleparam.h> 25 #include <linux/slab.h> 26 #include <linux/mtd/mtd.h> 27 28 #define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args) 29 30 struct phram_mtd_list { 31 struct mtd_info mtd; 32 struct list_head list; 33 }; 34 35 static LIST_HEAD(phram_list); 36 37 38 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr) 39 { 40 u_char *start = mtd->priv; 41 42 if (instr->addr + instr->len > mtd->size) 43 return -EINVAL; 44 45 memset(start + instr->addr, 0xff, instr->len); 46 47 /* This'll catch a few races. Free the thing before returning :) 48 * I don't feel at all ashamed. This kind of thing is possible anyway 49 * with flash, but unlikely. 50 */ 51 52 instr->state = MTD_ERASE_DONE; 53 54 mtd_erase_callback(instr); 55 56 return 0; 57 } 58 59 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len, 60 size_t *retlen, void **virt, resource_size_t *phys) 61 { 62 if (from + len > mtd->size) 63 return -EINVAL; 64 65 /* can we return a physical address with this driver? */ 66 if (phys) 67 return -EINVAL; 68 69 *virt = mtd->priv + from; 70 *retlen = len; 71 return 0; 72 } 73 74 static void phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 75 { 76 } 77 78 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len, 79 size_t *retlen, u_char *buf) 80 { 81 u_char *start = mtd->priv; 82 83 if (from >= mtd->size) 84 return -EINVAL; 85 86 if (len > mtd->size - from) 87 len = mtd->size - from; 88 89 memcpy(buf, start + from, len); 90 91 *retlen = len; 92 return 0; 93 } 94 95 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len, 96 size_t *retlen, const u_char *buf) 97 { 98 u_char *start = mtd->priv; 99 100 if (to >= mtd->size) 101 return -EINVAL; 102 103 if (len > mtd->size - to) 104 len = mtd->size - to; 105 106 memcpy(start + to, buf, len); 107 108 *retlen = len; 109 return 0; 110 } 111 112 113 114 static void unregister_devices(void) 115 { 116 struct phram_mtd_list *this, *safe; 117 118 list_for_each_entry_safe(this, safe, &phram_list, list) { 119 del_mtd_device(&this->mtd); 120 iounmap(this->mtd.priv); 121 kfree(this); 122 } 123 } 124 125 static int register_device(char *name, unsigned long start, unsigned long len) 126 { 127 struct phram_mtd_list *new; 128 int ret = -ENOMEM; 129 130 new = kzalloc(sizeof(*new), GFP_KERNEL); 131 if (!new) 132 goto out0; 133 134 ret = -EIO; 135 new->mtd.priv = ioremap(start, len); 136 if (!new->mtd.priv) { 137 ERROR("ioremap failed\n"); 138 goto out1; 139 } 140 141 142 new->mtd.name = name; 143 new->mtd.size = len; 144 new->mtd.flags = MTD_CAP_RAM; 145 new->mtd.erase = phram_erase; 146 new->mtd.point = phram_point; 147 new->mtd.unpoint = phram_unpoint; 148 new->mtd.read = phram_read; 149 new->mtd.write = phram_write; 150 new->mtd.owner = THIS_MODULE; 151 new->mtd.type = MTD_RAM; 152 new->mtd.erasesize = PAGE_SIZE; 153 new->mtd.writesize = 1; 154 155 ret = -EAGAIN; 156 if (add_mtd_device(&new->mtd)) { 157 ERROR("Failed to register new device\n"); 158 goto out2; 159 } 160 161 list_add_tail(&new->list, &phram_list); 162 return 0; 163 164 out2: 165 iounmap(new->mtd.priv); 166 out1: 167 kfree(new); 168 out0: 169 return ret; 170 } 171 172 static int ustrtoul(const char *cp, char **endp, unsigned int base) 173 { 174 unsigned long result = simple_strtoul(cp, endp, base); 175 176 switch (**endp) { 177 case 'G': 178 result *= 1024; 179 case 'M': 180 result *= 1024; 181 case 'k': 182 result *= 1024; 183 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ 184 if ((*endp)[1] == 'i') 185 (*endp) += 2; 186 } 187 return result; 188 } 189 190 static int parse_num32(uint32_t *num32, const char *token) 191 { 192 char *endp; 193 unsigned long n; 194 195 n = ustrtoul(token, &endp, 0); 196 if (*endp) 197 return -EINVAL; 198 199 *num32 = n; 200 return 0; 201 } 202 203 static int parse_name(char **pname, const char *token) 204 { 205 size_t len; 206 char *name; 207 208 len = strlen(token) + 1; 209 if (len > 64) 210 return -ENOSPC; 211 212 name = kmalloc(len, GFP_KERNEL); 213 if (!name) 214 return -ENOMEM; 215 216 strcpy(name, token); 217 218 *pname = name; 219 return 0; 220 } 221 222 223 static inline void kill_final_newline(char *str) 224 { 225 char *newline = strrchr(str, '\n'); 226 if (newline && !newline[1]) 227 *newline = 0; 228 } 229 230 231 #define parse_err(fmt, args...) do { \ 232 ERROR(fmt , ## args); \ 233 return 0; \ 234 } while (0) 235 236 static int phram_setup(const char *val, struct kernel_param *kp) 237 { 238 char buf[64+12+12], *str = buf; 239 char *token[3]; 240 char *name; 241 uint32_t start; 242 uint32_t len; 243 int i, ret; 244 245 if (strnlen(val, sizeof(buf)) >= sizeof(buf)) 246 parse_err("parameter too long\n"); 247 248 strcpy(str, val); 249 kill_final_newline(str); 250 251 for (i=0; i<3; i++) 252 token[i] = strsep(&str, ","); 253 254 if (str) 255 parse_err("too many arguments\n"); 256 257 if (!token[2]) 258 parse_err("not enough arguments\n"); 259 260 ret = parse_name(&name, token[0]); 261 if (ret == -ENOMEM) 262 parse_err("out of memory\n"); 263 if (ret == -ENOSPC) 264 parse_err("name too long\n"); 265 if (ret) 266 return 0; 267 268 ret = parse_num32(&start, token[1]); 269 if (ret) { 270 kfree(name); 271 parse_err("illegal start address\n"); 272 } 273 274 ret = parse_num32(&len, token[2]); 275 if (ret) { 276 kfree(name); 277 parse_err("illegal device length\n"); 278 } 279 280 register_device(name, start, len); 281 282 return 0; 283 } 284 285 module_param_call(phram, phram_setup, NULL, NULL, 000); 286 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\""); 287 288 289 static int __init init_phram(void) 290 { 291 return 0; 292 } 293 294 static void __exit cleanup_phram(void) 295 { 296 unregister_devices(); 297 } 298 299 module_init(init_phram); 300 module_exit(cleanup_phram); 301 302 MODULE_LICENSE("GPL"); 303 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>"); 304 MODULE_DESCRIPTION("MTD driver for physical RAM"); 305