1 /* 2 * mtdram - a test mtd device 3 * Author: Alexander Larsson <alex@cendio.se> 4 * 5 * Copyright (c) 1999 Alexander Larsson <alex@cendio.se> 6 * Copyright (c) 2005 Joern Engel <joern@wh.fh-wedel.de> 7 * 8 * This code is GPL 9 * 10 */ 11 12 #include <linux/module.h> 13 #include <linux/slab.h> 14 #include <linux/ioport.h> 15 #include <linux/vmalloc.h> 16 #include <linux/mm.h> 17 #include <linux/init.h> 18 #include <linux/mtd/mtd.h> 19 #include <linux/mtd/mtdram.h> 20 21 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE; 22 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE; 23 static unsigned long writebuf_size = 64; 24 #define MTDRAM_TOTAL_SIZE (total_size * 1024) 25 #define MTDRAM_ERASE_SIZE (erase_size * 1024) 26 27 #ifdef MODULE 28 module_param(total_size, ulong, 0); 29 MODULE_PARM_DESC(total_size, "Total device size in KiB"); 30 module_param(erase_size, ulong, 0); 31 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB"); 32 module_param(writebuf_size, ulong, 0); 33 MODULE_PARM_DESC(writebuf_size, "Device write buf size in Bytes (Default: 64)"); 34 #endif 35 36 // We could store these in the mtd structure, but we only support 1 device.. 37 static struct mtd_info *mtd_info; 38 39 static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len) 40 { 41 int ret = 0; 42 43 /* Start address must align on block boundary */ 44 if (mtd_mod_by_eb(ofs, mtd)) { 45 pr_debug("%s: unaligned address\n", __func__); 46 ret = -EINVAL; 47 } 48 49 /* Length must align on block boundary */ 50 if (mtd_mod_by_eb(len, mtd)) { 51 pr_debug("%s: length not block aligned\n", __func__); 52 ret = -EINVAL; 53 } 54 55 return ret; 56 } 57 58 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr) 59 { 60 if (check_offs_len(mtd, instr->addr, instr->len)) 61 return -EINVAL; 62 memset((char *)mtd->priv + instr->addr, 0xff, instr->len); 63 instr->state = MTD_ERASE_DONE; 64 mtd_erase_callback(instr); 65 return 0; 66 } 67 68 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len, 69 size_t *retlen, void **virt, resource_size_t *phys) 70 { 71 *virt = mtd->priv + from; 72 *retlen = len; 73 74 if (phys) { 75 /* limit retlen to the number of contiguous physical pages */ 76 unsigned long page_ofs = offset_in_page(*virt); 77 void *addr = *virt - page_ofs; 78 unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr); 79 80 *phys = __pfn_to_phys(pfn0) + page_ofs; 81 len += page_ofs; 82 while (len > PAGE_SIZE) { 83 len -= PAGE_SIZE; 84 addr += PAGE_SIZE; 85 pfn0++; 86 pfn1 = vmalloc_to_pfn(addr); 87 if (pfn1 != pfn0) { 88 *retlen = addr - *virt; 89 break; 90 } 91 } 92 } 93 94 return 0; 95 } 96 97 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 98 { 99 return 0; 100 } 101 102 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len, 103 size_t *retlen, u_char *buf) 104 { 105 memcpy(buf, mtd->priv + from, len); 106 *retlen = len; 107 return 0; 108 } 109 110 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len, 111 size_t *retlen, const u_char *buf) 112 { 113 memcpy((char *)mtd->priv + to, buf, len); 114 *retlen = len; 115 return 0; 116 } 117 118 static void __exit cleanup_mtdram(void) 119 { 120 if (mtd_info) { 121 mtd_device_unregister(mtd_info); 122 vfree(mtd_info->priv); 123 kfree(mtd_info); 124 } 125 } 126 127 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address, 128 unsigned long size, const char *name) 129 { 130 memset(mtd, 0, sizeof(*mtd)); 131 132 /* Setup the MTD structure */ 133 mtd->name = name; 134 mtd->type = MTD_RAM; 135 mtd->flags = MTD_CAP_RAM; 136 mtd->size = size; 137 mtd->writesize = 1; 138 mtd->writebufsize = writebuf_size; 139 mtd->erasesize = MTDRAM_ERASE_SIZE; 140 mtd->priv = mapped_address; 141 142 mtd->owner = THIS_MODULE; 143 mtd->_erase = ram_erase; 144 mtd->_point = ram_point; 145 mtd->_unpoint = ram_unpoint; 146 mtd->_read = ram_read; 147 mtd->_write = ram_write; 148 149 if (mtd_device_register(mtd, NULL, 0)) 150 return -EIO; 151 152 return 0; 153 } 154 155 static int __init init_mtdram(void) 156 { 157 void *addr; 158 int err; 159 160 if (!total_size) 161 return -EINVAL; 162 163 /* Allocate some memory */ 164 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL); 165 if (!mtd_info) 166 return -ENOMEM; 167 168 addr = vmalloc(MTDRAM_TOTAL_SIZE); 169 if (!addr) { 170 kfree(mtd_info); 171 mtd_info = NULL; 172 return -ENOMEM; 173 } 174 err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device"); 175 if (err) { 176 vfree(addr); 177 kfree(mtd_info); 178 mtd_info = NULL; 179 return err; 180 } 181 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE); 182 return err; 183 } 184 185 module_init(init_mtdram); 186 module_exit(cleanup_mtdram); 187 188 MODULE_LICENSE("GPL"); 189 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>"); 190 MODULE_DESCRIPTION("Simulated MTD driver for testing"); 191