1 files changed, 495 insertions, 0 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
new file mode 100644
index 000000000000..cfe6ccf07972
--- /dev/null
+++ b/drivers/mtd/devices/block2mtd.c
@@ -0,0 +1,495 @@
+/*
+ * $Id: block2mtd.c,v 1.23 2005/01/05 17:05:46 dwmw2 Exp $
+ *
+ * block2mtd.c - create an mtd from a block device
+ *
+ * Copyright (C) 2001,2002      Simon Evans <spse@secret.org.uk>
+ * Copyright (C) 2004           Gareth Bult <Gareth@Encryptec.net>
+ * Copyright (C) 2004,2005      Jörn Engel <joern@wh.fh-wedel.de>
+ *
+ * Licence: GPL
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/pagemap.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+#include <linux/buffer_head.h>
+
+#define VERSION "$Revision: 1.23 $"
+
+
+#define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args)
+#define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args)
+
+
+/* Info for the block device */
+struct block2mtd_dev {
+        struct list_head list;
+        struct block_device *blkdev;
+        struct mtd_info mtd;
+        struct semaphore write_mutex;
+};
+
+
+/* Static info about the MTD, used in cleanup_module */
+static LIST_HEAD(blkmtd_device_list);
+
+
+#define PAGE_READAHEAD 64
+void cache_readahead(struct address_space *mapping, int index)
+{
+        filler_t *filler = (filler_t*)mapping->a_ops->readpage;
+        int i, pagei;
+        unsigned ret = 0;
+        unsigned long end_index;
+        struct page *page;
+        LIST_HEAD(page_pool);
+        struct inode *inode = mapping->host;
+        loff_t isize = i_size_read(inode);
+
+        if (!isize) {
+                INFO("iSize=0 in cache_readahead\n");
+                return;
+        }
+
+        end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
+
+        read_lock_irq(&mapping->tree_lock);
+        for (i = 0; i < PAGE_READAHEAD; i++) {
+                pagei = index + i;
+                if (pagei > end_index) {
+                        INFO("Overrun end of disk in cache readahead\n");
+                        break;
+                }
+                page = radix_tree_lookup(&mapping->page_tree, pagei);
+                if (page && (!i))
+                        break;
+                if (page)
+                        continue;
+                read_unlock_irq(&mapping->tree_lock);
+                page = page_cache_alloc_cold(mapping);
+                read_lock_irq(&mapping->tree_lock);
+                if (!page)
+                        break;
+                page->index = pagei;
+                list_add(&page->lru, &page_pool);
+                ret++;
+        }
+        read_unlock_irq(&mapping->tree_lock);
+        if (ret)
+                read_cache_pages(mapping, &page_pool, filler, NULL);
+}
+
+
+static struct page* page_readahead(struct address_space *mapping, int index)
+{
+        filler_t *filler = (filler_t*)mapping->a_ops->readpage;
+        //do_page_cache_readahead(mapping, index, XXX, 64);
+        cache_readahead(mapping, index);
+        return read_cache_page(mapping, index, filler, NULL);
+}
+
+
+/* erase a specified part of the device */
+static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
+{
+        struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
+        struct page *page;
+        int index = to >> PAGE_SHIFT;   // page index
+        int pages = len >> PAGE_SHIFT;
+        u_long *p;
+        u_long *max;
+
+        while (pages) {
+                page = page_readahead(mapping, index);
+                if (!page)
+                        return -ENOMEM;
+                if (IS_ERR(page))
+                        return PTR_ERR(page);
+
+                max = (u_long*)page_address(page) + PAGE_SIZE;
+                for (p=(u_long*)page_address(page); p<max; p++) 
+                        if (*p != -1UL) {
+                                lock_page(page);
+                                memset(page_address(page), 0xff, PAGE_SIZE);
+                                set_page_dirty(page);
+                                unlock_page(page);
+                                break;
+                        }
+
+                page_cache_release(page);
+                pages--;
+                index++;
+        }
+        return 0;
+}
+static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+        struct block2mtd_dev *dev = mtd->priv;
+        size_t from = instr->addr;
+        size_t len = instr->len;
+        int err;
+
+        instr->state = MTD_ERASING;
+        down(&dev->write_mutex);
+        err = _block2mtd_erase(dev, from, len);
+        up(&dev->write_mutex);
+        if (err) {
+                ERROR("erase failed err = %d", err);
+                instr->state = MTD_ERASE_FAILED;
+        } else
+                instr->state = MTD_ERASE_DONE;
+
+        instr->state = MTD_ERASE_DONE;
+        mtd_erase_callback(instr);
+        return err;
+}
+
+
+static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+                size_t *retlen, u_char *buf)
+{
+        struct block2mtd_dev *dev = mtd->priv;
+        struct page *page;
+        int index = from >> PAGE_SHIFT;
+        int offset = from & (PAGE_SHIFT-1);
+        int cpylen;
+
+        if (from > mtd->size)
+                return -EINVAL;
+        if (from + len > mtd->size)
+                len = mtd->size - from;
+
+        if (retlen)
+                *retlen = 0;
+
+        while (len) {
+                if ((offset + len) > PAGE_SIZE)
+                        cpylen = PAGE_SIZE - offset;    // multiple pages
+                else
+                        cpylen = len;   // this page
+                len = len - cpylen;
+
+                //      Get page
+                page = page_readahead(dev->blkdev->bd_inode->i_mapping, index);
+                if (!page)
+                        return -ENOMEM;
+                if (IS_ERR(page))
+                        return PTR_ERR(page);
+
+                memcpy(buf, page_address(page) + offset, cpylen);
+                page_cache_release(page);
+
+                if (retlen)
+                        *retlen += cpylen;
+                buf += cpylen;
+                offset = 0;
+                index++;
+        }
+        return 0;
+}
+
+
+/* write data to the underlying device */
+static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
+                loff_t to, size_t len, size_t *retlen)
+{
+        struct page *page;
+        struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
+        int index = to >> PAGE_SHIFT;   // page index
+        int offset = to & ~PAGE_MASK;   // page offset
+        int cpylen;
+
+        if (retlen)
+                *retlen = 0;
+        while (len) {
+                if ((offset+len) > PAGE_SIZE) 
+                        cpylen = PAGE_SIZE - offset;    // multiple pages
+                else
+                        cpylen = len;                   // this page
+                len = len - cpylen;
+
+                //      Get page
+                page = page_readahead(mapping, index);
+                if (!page)
+                        return -ENOMEM;
+                if (IS_ERR(page))
+                        return PTR_ERR(page);
+
+                if (memcmp(page_address(page)+offset, buf, cpylen)) {
+                        lock_page(page);
+                        memcpy(page_address(page) + offset, buf, cpylen);
+                        set_page_dirty(page);
+                        unlock_page(page);
+                }
+                page_cache_release(page);
+
+                if (retlen)
+                        *retlen += cpylen;
+
+                buf += cpylen;
+                offset = 0;
+                index++;
+        }
+        return 0;
+}
+static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
+                size_t *retlen, const u_char *buf)
+{
+        struct block2mtd_dev *dev = mtd->priv;
+        int err;
+
+        if (!len)
+                return 0;
+        if (to >= mtd->size)
+                return -ENOSPC;
+        if (to + len > mtd->size)
+                len = mtd->size - to;
+
+        down(&dev->write_mutex);
+        err = _block2mtd_write(dev, buf, to, len, retlen);
+        up(&dev->write_mutex);
+        if (err > 0)
+                err = 0;
+        return err;
+}
+
+
+/* sync the device - wait until the write queue is empty */
+static void block2mtd_sync(struct mtd_info *mtd)
+{
+        struct block2mtd_dev *dev = mtd->priv;
+        sync_blockdev(dev->blkdev);
+        return;
+}
+
+
+static void block2mtd_free_device(struct block2mtd_dev *dev)
+{
+        if (!dev)
+                return;
+
+        kfree(dev->mtd.name);
+
+        if (dev->blkdev) {
+                invalidate_inode_pages(dev->blkdev->bd_inode->i_mapping);
+                close_bdev_excl(dev->blkdev);
+        }
+
+        kfree(dev);
+}
+
+
+/* FIXME: ensure that mtd->size % erase_size == 0 */
+static struct block2mtd_dev *add_device(char *devname, int erase_size)
+{
+        struct block_device *bdev;
+        struct block2mtd_dev *dev;
+
+        if (!devname)
+                return NULL;
+
+        dev = kmalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
+        if (!dev)
+                return NULL;
+        memset(dev, 0, sizeof(*dev));
+
+        /* Get a handle on the device */
+        bdev = open_bdev_excl(devname, O_RDWR, NULL);
+        if (IS_ERR(bdev)) {
+                ERROR("error: cannot open device %s", devname);
+                goto devinit_err;
+        }
+        dev->blkdev = bdev;
+
+        if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
+                ERROR("attempting to use an MTD device as a block device");
+                goto devinit_err;
+        }
+
+        init_MUTEX(&dev->write_mutex);
+
+        /* Setup the MTD structure */
+        /* make the name contain the block device in */
+        dev->mtd.name = kmalloc(sizeof("block2mtd: ") + strlen(devname),
+                        GFP_KERNEL);
+        if (!dev->mtd.name)
+                goto devinit_err;
+
+        sprintf(dev->mtd.name, "block2mtd: %s", devname);
+
+        dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
+        dev->mtd.erasesize = erase_size;
+        dev->mtd.type = MTD_RAM;
+        dev->mtd.flags = MTD_CAP_RAM;
+        dev->mtd.erase = block2mtd_erase;
+        dev->mtd.write = block2mtd_write;
+        dev->mtd.writev = default_mtd_writev;
+        dev->mtd.sync = block2mtd_sync;
+        dev->mtd.read = block2mtd_read;
+        dev->mtd.readv = default_mtd_readv;
+        dev->mtd.priv = dev;
+        dev->mtd.owner = THIS_MODULE;
+
+        if (add_mtd_device(&dev->mtd)) {
+                /* Device didnt get added, so free the entry */
+                goto devinit_err;
+        }
+        list_add(&dev->list, &blkmtd_device_list);
+        INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index,
+                        dev->mtd.name + strlen("blkmtd: "),
+                        dev->mtd.erasesize >> 10, dev->mtd.erasesize);
+        return dev;
+
+devinit_err:
+        block2mtd_free_device(dev);
+        return NULL;
+}
+
+
+static int ustrtoul(const char *cp, char **endp, unsigned int base)
+{
+        unsigned long result = simple_strtoul(cp, endp, base);
+        switch (**endp) {
+        case 'G' :
+                result *= 1024;
+        case 'M':
+                result *= 1024;
+        case 'k':
+                result *= 1024;
+        /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
+                if ((*endp)[1] == 'i')
+                        (*endp) += 2;
+        }
+        return result;
+}
+
+
+static int parse_num32(u32 *num32, const char *token)
+{
+        char *endp;
+        unsigned long n;
+
+        n = ustrtoul(token, &endp, 0);
+        if (*endp)
+                return -EINVAL;
+
+        *num32 = n;
+        return 0;
+}
+
+
+static int parse_name(char **pname, const char *token, size_t limit)
+{
+        size_t len;
+        char *name;
+
+        len = strlen(token) + 1;
+        if (len > limit)
+                return -ENOSPC;
+
+        name = kmalloc(len, GFP_KERNEL);
+        if (!name)
+                return -ENOMEM;
+
+        strcpy(name, token);
+
+        *pname = name;
+        return 0;
+}
+
+
+static inline void kill_final_newline(char *str)
+{
+        char *newline = strrchr(str, '\n');
+        if (newline && !newline[1])
+                *newline = 0;
+}
+
+
+#define parse_err(fmt, args...) do {            \
+        ERROR("block2mtd: " fmt "\n", ## args); \
+        return 0;                               \
+} while (0)
+
+static int block2mtd_setup(const char *val, struct kernel_param *kp)
+{
+        char buf[80+12], *str=buf; /* 80 for device, 12 for erase size */
+        char *token[2];
+        char *name;
+        u32 erase_size = PAGE_SIZE;
+        int i, ret;
+
+        if (strnlen(val, sizeof(buf)) >= sizeof(buf))
+                parse_err("parameter too long");
+
+        strcpy(str, val);
+        kill_final_newline(str);
+
+        for (i=0; i<2; i++)
+                token[i] = strsep(&str, ",");
+
+        if (str)
+                parse_err("too many arguments");
+
+        if (!token[0])
+                parse_err("no argument");
+
+        ret = parse_name(&name, token[0], 80);
+        if (ret == -ENOMEM)
+                parse_err("out of memory");
+        if (ret == -ENOSPC)
+                parse_err("name too long");
+        if (ret)
+                return 0;
+
+        if (token[1]) {
+                ret = parse_num32(&erase_size, token[1]);
+                if (ret)
+                        parse_err("illegal erase size");
+        }
+
+        add_device(name, erase_size);
+
+        return 0;
+}
+
+
+module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
+MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
+
+static int __init block2mtd_init(void)
+{
+        INFO("version " VERSION);
+        return 0;
+}
+
+
+static void __devexit block2mtd_exit(void)
+{
+        struct list_head *pos, *next;
+
+        /* Remove the MTD devices */
+        list_for_each_safe(pos, next, &blkmtd_device_list) {
+                struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list);
+                block2mtd_sync(&dev->mtd);
+                del_mtd_device(&dev->mtd);
+                INFO("mtd%d: [%s] removed", dev->mtd.index,
+                                dev->mtd.name + strlen("blkmtd: "));
+                list_del(&dev->list);
+                block2mtd_free_device(dev);
+        }
+}
+
+
+module_init(block2mtd_init);
+module_exit(block2mtd_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Simon Evans <spse@secret.org.uk> and others");
+MODULE_DESCRIPTION("Emulate an MTD using a block device");