1 /** 2 * $Id: phram.c,v 1.11 2005/01/05 18:05:13 dwmw2 Exp $ 3 * 4 * Copyright (c) ???? Jochen Sch�uble <psionic@psionic.de> 5 * Copyright (c) 2003-2004 J�rn 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 */ 20 21 #include <asm/io.h> 22 #include <linux/init.h> 23 #include <linux/kernel.h> 24 #include <linux/list.h> 25 #include <linux/module.h> 26 #include <linux/moduleparam.h> 27 #include <linux/mtd/mtd.h> 28 29 #define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args) 30 31 struct phram_mtd_list { 32 struct mtd_info mtd; 33 struct list_head list; 34 }; 35 36 static LIST_HEAD(phram_list); 37 38 39 40 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr) 41 { 42 u_char *start = mtd->priv; 43 44 if (instr->addr + instr->len > mtd->size) 45 return -EINVAL; 46 47 memset(start + instr->addr, 0xff, instr->len); 48 49 /* This'll catch a few races. Free the thing before returning :) 50 * I don't feel at all ashamed. This kind of thing is possible anyway 51 * with flash, but unlikely. 52 */ 53 54 instr->state = MTD_ERASE_DONE; 55 56 mtd_erase_callback(instr); 57 58 return 0; 59 } 60 61 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len, 62 size_t *retlen, u_char **mtdbuf) 63 { 64 u_char *start = mtd->priv; 65 66 if (from + len > mtd->size) 67 return -EINVAL; 68 69 *mtdbuf = start + from; 70 *retlen = len; 71 return 0; 72 } 73 74 static void phram_unpoint(struct mtd_info *mtd, u_char *addr, 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 + len > mtd->size) 84 return -EINVAL; 85 86 memcpy(buf, start + from, len); 87 88 *retlen = len; 89 return 0; 90 } 91 92 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len, 93 size_t *retlen, const u_char *buf) 94 { 95 u_char *start = mtd->priv; 96 97 if (to + len > mtd->size) 98 return -EINVAL; 99 100 memcpy(start + to, buf, len); 101 102 *retlen = len; 103 return 0; 104 } 105 106 107 108 static void unregister_devices(void) 109 { 110 struct phram_mtd_list *this; 111 112 list_for_each_entry(this, &phram_list, list) { 113 del_mtd_device(&this->mtd); 114 iounmap(this->mtd.priv); 115 kfree(this); 116 } 117 } 118 119 static int register_device(char *name, unsigned long start, unsigned long len) 120 { 121 struct phram_mtd_list *new; 122 int ret = -ENOMEM; 123 124 new = kmalloc(sizeof(*new), GFP_KERNEL); 125 if (!new) 126 goto out0; 127 128 memset(new, 0, sizeof(*new)); 129 130 ret = -EIO; 131 new->mtd.priv = ioremap(start, len); 132 if (!new->mtd.priv) { 133 ERROR("ioremap failed\n"); 134 goto out1; 135 } 136 137 138 new->mtd.name = name; 139 new->mtd.size = len; 140 new->mtd.flags = MTD_CAP_RAM | MTD_ERASEABLE | MTD_VOLATILE; 141 new->mtd.erase = phram_erase; 142 new->mtd.point = phram_point; 143 new->mtd.unpoint = phram_unpoint; 144 new->mtd.read = phram_read; 145 new->mtd.write = phram_write; 146 new->mtd.owner = THIS_MODULE; 147 new->mtd.type = MTD_RAM; 148 new->mtd.erasesize = 0; 149 150 ret = -EAGAIN; 151 if (add_mtd_device(&new->mtd)) { 152 ERROR("Failed to register new device\n"); 153 goto out2; 154 } 155 156 list_add_tail(&new->list, &phram_list); 157 return 0; 158 159 out2: 160 iounmap(new->mtd.priv); 161 out1: 162 kfree(new); 163 out0: 164 return ret; 165 } 166 167 static int ustrtoul(const char *cp, char **endp, unsigned int base) 168 { 169 unsigned long result = simple_strtoul(cp, endp, base); 170 171 switch (**endp) { 172 case 'G': 173 result *= 1024; 174 case 'M': 175 result *= 1024; 176 case 'k': 177 result *= 1024; 178 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ 179 if ((*endp)[1] == 'i') 180 (*endp) += 2; 181 } 182 return result; 183 } 184 185 static int parse_num32(uint32_t *num32, const char *token) 186 { 187 char *endp; 188 unsigned long n; 189 190 n = ustrtoul(token, &endp, 0); 191 if (*endp) 192 return -EINVAL; 193 194 *num32 = n; 195 return 0; 196 } 197 198 static int parse_name(char **pname, const char *token) 199 { 200 size_t len; 201 char *name; 202 203 len = strlen(token) + 1; 204 if (len > 64) 205 return -ENOSPC; 206 207 name = kmalloc(len, GFP_KERNEL); 208 if (!name) 209 return -ENOMEM; 210 211 strcpy(name, token); 212 213 *pname = name; 214 return 0; 215 } 216 217 #define parse_err(fmt, args...) do { \ 218 ERROR(fmt , ## args); \ 219 return 0; \ 220 } while (0) 221 222 static int phram_setup(const char *val, struct kernel_param *kp) 223 { 224 char buf[64+12+12], *str = buf; 225 char *token[3]; 226 char *name; 227 uint32_t start; 228 uint32_t len; 229 int i, ret; 230 231 if (strnlen(val, sizeof(buf)) >= sizeof(buf)) 232 parse_err("parameter too long\n"); 233 234 strcpy(str, val); 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 == -ENOMEM) 247 parse_err("out of memory\n"); 248 if (ret == -ENOSPC) 249 parse_err("name too long\n"); 250 if (ret) 251 return 0; 252 253 ret = parse_num32(&start, token[1]); 254 if (ret) 255 parse_err("illegal start address\n"); 256 257 ret = parse_num32(&len, token[2]); 258 if (ret) 259 parse_err("illegal device length\n"); 260 261 register_device(name, start, len); 262 263 return 0; 264 } 265 266 module_param_call(phram, phram_setup, NULL, NULL, 000); 267 MODULE_PARM_DESC(phram,"Memory region to map. \"map=<name>,<start>,<length>\""); 268 269 270 static int __init init_phram(void) 271 { 272 return 0; 273 } 274 275 static void __exit cleanup_phram(void) 276 { 277 unregister_devices(); 278 } 279 280 module_init(init_phram); 281 module_exit(cleanup_phram); 282 283 MODULE_LICENSE("GPL"); 284 MODULE_AUTHOR("J�rn Engel <joern@wh.fh-wedel.de>"); 285 MODULE_DESCRIPTION("MTD driver for physical RAM"); 286