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