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 64 return 0; 65 } 66 67 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len, 68 size_t *retlen, void **virt, resource_size_t *phys) 69 { 70 *virt = mtd->priv + from; 71 *retlen = len; 72 73 if (phys) { 74 /* limit retlen to the number of contiguous physical pages */ 75 unsigned long page_ofs = offset_in_page(*virt); 76 void *addr = *virt - page_ofs; 77 unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr); 78 79 *phys = __pfn_to_phys(pfn0) + page_ofs; 80 len += page_ofs; 81 while (len > PAGE_SIZE) { 82 len -= PAGE_SIZE; 83 addr += PAGE_SIZE; 84 pfn0++; 85 pfn1 = vmalloc_to_pfn(addr); 86 if (pfn1 != pfn0) { 87 *retlen = addr - *virt; 88 break; 89 } 90 } 91 } 92 93 return 0; 94 } 95 96 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 97 { 98 return 0; 99 } 100 101 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len, 102 size_t *retlen, u_char *buf) 103 { 104 memcpy(buf, mtd->priv + from, len); 105 *retlen = len; 106 return 0; 107 } 108 109 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len, 110 size_t *retlen, const u_char *buf) 111 { 112 memcpy((char *)mtd->priv + to, buf, len); 113 *retlen = len; 114 return 0; 115 } 116 117 static void __exit cleanup_mtdram(void) 118 { 119 if (mtd_info) { 120 mtd_device_unregister(mtd_info); 121 vfree(mtd_info->priv); 122 kfree(mtd_info); 123 } 124 } 125 126 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address, 127 unsigned long size, const char *name) 128 { 129 memset(mtd, 0, sizeof(*mtd)); 130 131 /* Setup the MTD structure */ 132 mtd->name = name; 133 mtd->type = MTD_RAM; 134 mtd->flags = MTD_CAP_RAM; 135 mtd->size = size; 136 mtd->writesize = 1; 137 mtd->writebufsize = writebuf_size; 138 mtd->erasesize = MTDRAM_ERASE_SIZE; 139 mtd->priv = mapped_address; 140 141 mtd->owner = THIS_MODULE; 142 mtd->_erase = ram_erase; 143 mtd->_point = ram_point; 144 mtd->_unpoint = ram_unpoint; 145 mtd->_read = ram_read; 146 mtd->_write = ram_write; 147 148 if (mtd_device_register(mtd, NULL, 0)) 149 return -EIO; 150 151 return 0; 152 } 153 154 static int __init init_mtdram(void) 155 { 156 void *addr; 157 int err; 158 159 if (!total_size) 160 return -EINVAL; 161 162 /* Allocate some memory */ 163 mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL); 164 if (!mtd_info) 165 return -ENOMEM; 166 167 addr = vmalloc(MTDRAM_TOTAL_SIZE); 168 if (!addr) { 169 kfree(mtd_info); 170 mtd_info = NULL; 171 return -ENOMEM; 172 } 173 err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device"); 174 if (err) { 175 vfree(addr); 176 kfree(mtd_info); 177 mtd_info = NULL; 178 return err; 179 } 180 memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE); 181 return err; 182 } 183 184 module_init(init_mtdram); 185 module_exit(cleanup_mtdram); 186 187 MODULE_LICENSE("GPL"); 188 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>"); 189 MODULE_DESCRIPTION("Simulated MTD driver for testing"); 190