/* * MTD device concatenation layer * * (C) 2002 Robert Kaiser * * This code is GPL * * $Id: mtdconcat.c,v 1.2 2002/03/22 08:45:22 dwmw2 Exp $ */ #include #include #include #include #include #include /* * Our storage structure: * Subdev points to an array of pointers to struct mtd_info objects * which is allocated along with this structure * */ struct mtd_concat { struct mtd_info mtd; int num_subdev; struct mtd_info **subdev; }; /* * how to calculate the size required for the above structure, * including the pointer array subdev points to: */ #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev) \ ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *))) /* * Given a pointer to the MTD object in the mtd_concat structure, * we can retrieve the pointer to that structure with this macro. */ #define CONCAT(x) ((struct mtd_concat *)(x)) /* * MTD methods which look up the relevant subdevice, translate the * effective address and pass through to the subdevice. */ static int concat_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { struct mtd_concat *concat = CONCAT(mtd); int err = -EINVAL; int i; *retlen = 0; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; size_t size, retsize; if (from >= subdev->size) { size = 0; from -= subdev->size; } else { if (from + len > subdev->size) size = subdev->size - from; else size = len; err = subdev->read(subdev, from, size, &retsize, buf); if(err) break; *retlen += retsize; len -= size; if(len == 0) break; err = -EINVAL; buf += size; from = 0; } } return err; } static int concat_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) { struct mtd_concat *concat = CONCAT(mtd); int err = -EINVAL; int i; if (!(mtd->flags & MTD_WRITEABLE)) return -EROFS; *retlen = 0; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; size_t size, retsize; if (to >= subdev->size) { size = 0; to -= subdev->size; } else { if (to + len > subdev->size) size = subdev->size - to; else size = len; if (!(subdev->flags & MTD_WRITEABLE)) err = -EROFS; else err = subdev->write(subdev, to, size, &retsize, buf); if(err) break; *retlen += retsize; len -= size; if(len == 0) break; err = -EINVAL; buf += size; to = 0; } } return err; } static void concat_erase_callback (struct erase_info *instr) { wake_up((wait_queue_head_t *)instr->priv); } static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase) { int err; wait_queue_head_t waitq; DECLARE_WAITQUEUE(wait, current); /* * This code was stol^H^H^H^Hinspired by mtdchar.c */ init_waitqueue_head(&waitq); erase->mtd = mtd; erase->callback = concat_erase_callback; erase->priv = (unsigned long)&waitq; /* * FIXME: Allow INTERRUPTIBLE. Which means * not having the wait_queue head on the stack. */ err = mtd->erase(mtd, erase); if (!err) { set_current_state(TASK_UNINTERRUPTIBLE); add_wait_queue(&waitq, &wait); if (erase->state != MTD_ERASE_DONE && erase->state != MTD_ERASE_FAILED) schedule(); remove_wait_queue(&waitq, &wait); set_current_state(TASK_RUNNING); err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0; } return err; } static int concat_erase (struct mtd_info *mtd, struct erase_info *instr) { struct mtd_concat *concat = CONCAT(mtd); struct mtd_info *subdev; int i, err; u_int32_t length; struct erase_info *erase; if (!(mtd->flags & MTD_WRITEABLE)) return -EROFS; if(instr->addr > concat->mtd.size) return -EINVAL; if(instr->len + instr->addr > concat->mtd.size) return -EINVAL; /* * Check for proper erase block alignment of the to-be-erased area. * It is easier to do this based on the super device's erase * region info rather than looking at each particular sub-device * in turn. */ if (!concat->mtd.numeraseregions) { /* the easy case: device has uniform erase block size */ if(instr->addr & (concat->mtd.erasesize - 1)) return -EINVAL; if(instr->len & (concat->mtd.erasesize - 1)) return -EINVAL; } else { /* device has variable erase size */ struct mtd_erase_region_info *erase_regions = concat->mtd.eraseregions; /* * Find the erase region where the to-be-erased area begins: */ for(i = 0; i < concat->mtd.numeraseregions && instr->addr >= erase_regions[i].offset; i++) ; --i; /* * Now erase_regions[i] is the region in which the * to-be-erased area begins. Verify that the starting * offset is aligned to this region's erase size: */ if (instr->addr & (erase_regions[i].erasesize-1)) return -EINVAL; /* * now find the erase region where the to-be-erased area ends: */ for(; i < concat->mtd.numeraseregions && (instr->addr + instr->len) >= erase_regions[i].offset ; ++i) ; --i; /* * check if the ending offset is aligned to this region's erase size */ if ((instr->addr + instr->len) & (erase_regions[i].erasesize-1)) return -EINVAL; } /* make a local copy of instr to avoid modifying the caller's struct */ erase = kmalloc(sizeof(struct erase_info),GFP_KERNEL); if (!erase) return -ENOMEM; *erase = *instr; length = instr->len; /* * find the subdevice where the to-be-erased area begins, adjust * starting offset to be relative to the subdevice start */ for(i = 0; i < concat->num_subdev; i++) { subdev = concat->subdev[i]; if(subdev->size <= erase->addr) erase->addr -= subdev->size; else break; } if(i >= concat->num_subdev) /* must never happen since size */ BUG(); /* limit has been verified above */ /* now do the erase: */ err = 0; for(;length > 0; i++) /* loop for all subevices affected by this request */ { subdev = concat->subdev[i]; /* get current subdevice */ /* limit length to subdevice's size: */ if(erase->addr + length > subdev->size) erase->len = subdev->size - erase->addr; else erase->len = length; if (!(subdev->flags & MTD_WRITEABLE)) { err = -EROFS; break; } length -= erase->len; if ((err = concat_dev_erase(subdev, erase))) { if(err == -EINVAL) /* sanity check: must never happen since */ BUG(); /* block alignment has been checked above */ break; } /* * erase->addr specifies the offset of the area to be * erased *within the current subdevice*. It can be * non-zero only the first time through this loop, i.e. * for the first subdevice where blocks need to be erased. * All the following erases must begin at the start of the * current subdevice, i.e. at offset zero. */ erase->addr = 0; } instr->state = MTD_ERASE_DONE; if (instr->callback) instr->callback(instr); kfree(erase); return err; } static int concat_lock (struct mtd_info *mtd, loff_t ofs, size_t len) { struct mtd_concat *concat = CONCAT(mtd); int i, err = -EINVAL; if ((len + ofs) > mtd->size) return -EINVAL; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; size_t size; if (ofs >= subdev->size) { size = 0; ofs -= subdev->size; } else { if (ofs + len > subdev->size) size = subdev->size - ofs; else size = len; err = subdev->lock(subdev, ofs, size); if(err) break; len -= size; if(len == 0) break; err = -EINVAL; ofs = 0; } } return err; } static int concat_unlock (struct mtd_info *mtd, loff_t ofs, size_t len) { struct mtd_concat *concat = CONCAT(mtd); int i, err = 0; if ((len + ofs) > mtd->size) return -EINVAL; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; size_t size; if (ofs >= subdev->size) { size = 0; ofs -= subdev->size; } else { if (ofs + len > subdev->size) size = subdev->size - ofs; else size = len; err = subdev->unlock(subdev, ofs, size); if(err) break; len -= size; if(len == 0) break; err = -EINVAL; ofs = 0; } } return err; } static void concat_sync(struct mtd_info *mtd) { struct mtd_concat *concat = CONCAT(mtd); int i; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; subdev->sync(subdev); } } static int concat_suspend(struct mtd_info *mtd) { struct mtd_concat *concat = CONCAT(mtd); int i, rc = 0; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; if((rc = subdev->suspend(subdev)) < 0) return rc; } return rc; } static void concat_resume(struct mtd_info *mtd) { struct mtd_concat *concat = CONCAT(mtd); int i; for(i = 0; i < concat->num_subdev; i++) { struct mtd_info *subdev = concat->subdev[i]; subdev->resume(subdev); } } /* * This function constructs a virtual MTD device by concatenating * num_devs MTD devices. A pointer to the new device object is * stored to *new_dev upon success. This function does _not_ * register any devices: this is the caller's responsibility. */ struct mtd_info *mtd_concat_create( struct mtd_info *subdev[], /* subdevices to concatenate */ int num_devs, /* number of subdevices */ char *name) /* name for the new device */ { int i; size_t size; struct mtd_concat *concat; u_int32_t max_erasesize, curr_erasesize; int num_erase_region; printk(KERN_NOTICE "Concatenating MTD devices:\n"); for(i = 0; i < num_devs; i++) printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name); printk(KERN_NOTICE "into device \"%s\"\n", name); /* allocate the device structure */ size = SIZEOF_STRUCT_MTD_CONCAT(num_devs); concat = kmalloc (size, GFP_KERNEL); if(!concat) { printk ("memory allocation error while creating concatenated device \"%s\"\n", name); return NULL; } memset(concat, 0, size); concat->subdev = (struct mtd_info **)(concat + 1); /* * Set up the new "super" device's MTD object structure, check for * incompatibilites between the subdevices. */ concat->mtd.type = subdev[0]->type; concat->mtd.flags = subdev[0]->flags; concat->mtd.size = subdev[0]->size; concat->mtd.erasesize = subdev[0]->erasesize; concat->mtd.oobblock = subdev[0]->oobblock; concat->mtd.oobsize = subdev[0]->oobsize; concat->mtd.ecctype = subdev[0]->ecctype; concat->mtd.eccsize = subdev[0]->eccsize; concat->subdev[0] = subdev[0]; for(i = 1; i < num_devs; i++) { if(concat->mtd.type != subdev[i]->type) { kfree(concat); printk ("Incompatible device type on \"%s\"\n", subdev[i]->name); return NULL; } if(concat->mtd.flags != subdev[i]->flags) { /* * Expect all flags except MTD_WRITEABLE to be equal on * all subdevices. */ if((concat->mtd.flags ^ subdev[i]->flags) & ~MTD_WRITEABLE) { kfree(concat); printk ("Incompatible device flags on \"%s\"\n", subdev[i]->name); return NULL; } else /* if writeable attribute differs, make super device writeable */ concat->mtd.flags |= subdev[i]->flags & MTD_WRITEABLE; } concat->mtd.size += subdev[i]->size; if(concat->mtd.oobblock != subdev[i]->oobblock || concat->mtd.oobsize != subdev[i]->oobsize || concat->mtd.ecctype != subdev[i]->ecctype || concat->mtd.eccsize != subdev[i]->eccsize) { kfree(concat); printk ("Incompatible OOB or ECC data on \"%s\"\n", subdev[i]->name); return NULL; } concat->subdev[i] = subdev[i]; } concat->num_subdev = num_devs; concat->mtd.name = name; /* * NOTE: for now, we do not provide any readv()/writev() methods * because they are messy to implement and they are not * used to a great extent anyway. */ concat->mtd.erase = concat_erase; concat->mtd.read = concat_read; concat->mtd.write = concat_write; concat->mtd.sync = concat_sync; concat->mtd.lock = concat_lock; concat->mtd.unlock = concat_unlock; concat->mtd.suspend = concat_suspend; concat->mtd.resume = concat_resume; /* * Combine the erase block size info of the subdevices: * * first, walk the map of the new device and see how * many changes in erase size we have */ max_erasesize = curr_erasesize = subdev[0]->erasesize; num_erase_region = 1; for(i = 0; i < num_devs; i++) { if(subdev[i]->numeraseregions == 0) { /* current subdevice has uniform erase size */ if(subdev[i]->erasesize != curr_erasesize) { /* if it differs from the last subdevice's erase size, count it */ ++num_erase_region; curr_erasesize = subdev[i]->erasesize; if(curr_erasesize > max_erasesize) max_erasesize = curr_erasesize; } } else { /* current subdevice has variable erase size */ int j; for(j = 0; j < subdev[i]->numeraseregions; j++) { /* walk the list of erase regions, count any changes */ if(subdev[i]->eraseregions[j].erasesize != curr_erasesize) { ++num_erase_region; curr_erasesize = subdev[i]->eraseregions[j].erasesize; if(curr_erasesize > max_erasesize) max_erasesize = curr_erasesize; } } } } if(num_erase_region == 1) { /* * All subdevices have the same uniform erase size. * This is easy: */ concat->mtd.erasesize = curr_erasesize; concat->mtd.numeraseregions = 0; } else { /* * erase block size varies across the subdevices: allocate * space to store the data describing the variable erase regions */ struct mtd_erase_region_info *erase_region_p; u_int32_t begin, position; concat->mtd.erasesize = max_erasesize; concat->mtd.numeraseregions = num_erase_region; concat->mtd.eraseregions = erase_region_p = kmalloc ( num_erase_region * sizeof(struct mtd_erase_region_info), GFP_KERNEL); if(!erase_region_p) { kfree(concat); printk ("memory allocation error while creating erase region list" " for device \"%s\"\n", name); return NULL; } /* * walk the map of the new device once more and fill in * in erase region info: */ curr_erasesize = subdev[0]->erasesize; begin = position = 0; for(i = 0; i < num_devs; i++) { if(subdev[i]->numeraseregions == 0) { /* current subdevice has uniform erase size */ if(subdev[i]->erasesize != curr_erasesize) { /* * fill in an mtd_erase_region_info structure for the area * we have walked so far: */ erase_region_p->offset = begin; erase_region_p->erasesize = curr_erasesize; erase_region_p->numblocks = (position - begin) / curr_erasesize; begin = position; curr_erasesize = subdev[i]->erasesize; ++erase_region_p; } position += subdev[i]->size; } else { /* current subdevice has variable erase size */ int j; for(j = 0; j < subdev[i]->numeraseregions; j++) { /* walk the list of erase regions, count any changes */ if(subdev[i]->eraseregions[j].erasesize != curr_erasesize) { erase_region_p->offset = begin; erase_region_p->erasesize = curr_erasesize; erase_region_p->numblocks = (position - begin) / curr_erasesize; begin = position; curr_erasesize = subdev[i]->eraseregions[j].erasesize; ++erase_region_p; } position += subdev[i]->eraseregions[j].numblocks * curr_erasesize; } } } /* Now write the final entry */ erase_region_p->offset = begin; erase_region_p->erasesize = curr_erasesize; erase_region_p->numblocks = (position - begin) / curr_erasesize; } return &concat->mtd; } /* * This function destroys an MTD object obtained from concat_mtd_devs() */ void mtd_concat_destroy(struct mtd_info *mtd) { struct mtd_concat *concat = CONCAT(mtd); if(concat->mtd.numeraseregions) kfree(concat->mtd.eraseregions); kfree(concat); } EXPORT_SYMBOL(mtd_concat_create); EXPORT_SYMBOL(mtd_concat_destroy); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Robert Kaiser "); MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");