cregit-Linux how code gets into the kernel

Release 4.7 drivers/mtd/rfd_ftl.c

Directory: drivers/mtd
/*
 * rfd_ftl.c -- resident flash disk (flash translation layer)
 *
 * Copyright © 2005  Sean Young <sean@mess.org>
 *
 * This type of flash translation layer (FTL) is used by the Embedded BIOS
 * by General Software. It is known as the Resident Flash Disk (RFD), see:
 *
 *      http://www.gensw.com/pages/prod/bios/rfd.htm
 *
 * based on ftl.c
 */

#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/mtd/blktrans.h>
#include <linux/mtd/mtd.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/module.h>

#include <asm/types.h>


static int block_size = 0;
module_param(block_size, int, 0);
MODULE_PARM_DESC(block_size, "Block size to use by RFD, defaults to erase unit size");


#define PREFIX "rfd_ftl: "

/* This major has been assigned by device@lanana.org */
#ifndef RFD_FTL_MAJOR

#define RFD_FTL_MAJOR		256
#endif

/* Maximum number of partitions in an FTL region */

#define PART_BITS		4

/* An erase unit should start with this value */

#define RFD_MAGIC		0x9193

/* the second value is 0xffff or 0xffc8; function unknown */

/* the third value is always 0xffff, ignored */

/* next is an array of mapping for each corresponding sector */

#define HEADER_MAP_OFFSET	3

#define SECTOR_DELETED		0x0000

#define SECTOR_ZERO		0xfffe

#define SECTOR_FREE		0xffff


#define SECTOR_SIZE		512


#define SECTORS_PER_TRACK	63


struct block {
	enum {
		
BLOCK_OK,
		
BLOCK_ERASING,
		
BLOCK_ERASED,
		
BLOCK_UNUSED,
		
BLOCK_FAILED
	} 
state;
	
int free_sectors;
	
int used_sectors;
	
int erases;
	
u_long offset;
};


struct partition {
	
struct mtd_blktrans_dev mbd;

	
u_int block_size;		/* size of erase unit */
	
u_int total_blocks;		/* number of erase units */
	
u_int header_sectors_per_block;	/* header sectors in erase unit */
	
u_int data_sectors_per_block;	/* data sectors in erase unit */
	
u_int sector_count;		/* sectors in translated disk */
	
u_int header_size;		/* bytes in header sector */
	
int reserved_block;		/* block next up for reclaim */
	
int current_block;		/* block to write to */
	
u16 *header_cache;		/* cached header */

	
int is_reclaiming;
	
int cylinders;
	
int errors;
	
u_long *sector_map;
	
struct block *blocks;
};

static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf);


static int build_block_map(struct partition *part, int block_no) { struct block *block = &part->blocks[block_no]; int i; block->offset = part->block_size * block_no; if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) { block->state = BLOCK_UNUSED; return -ENOENT; } block->state = BLOCK_OK; for (i=0; i<part->data_sectors_per_block; i++) { u16 entry; entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]); if (entry == SECTOR_DELETED) continue; if (entry == SECTOR_FREE) { block->free_sectors++; continue; } if (entry == SECTOR_ZERO) entry = 0; if (entry >= part->sector_count) { printk(KERN_WARNING PREFIX "'%s': unit #%d: entry %d corrupt, " "sector %d out of range\n", part->mbd.mtd->name, block_no, i, entry); continue; } if (part->sector_map[entry] != -1) { printk(KERN_WARNING PREFIX "'%s': more than one entry for sector %d\n", part->mbd.mtd->name, entry); part->errors = 1; continue; } part->sector_map[entry] = block->offset + (i + part->header_sectors_per_block) * SECTOR_SIZE; block->used_sectors++; } if (block->free_sectors == part->data_sectors_per_block) part->reserved_block = block_no; return 0; }

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static int scan_header(struct partition *part) { int sectors_per_block; int i, rc = -ENOMEM; int blocks_found; size_t retlen; sectors_per_block = part->block_size / SECTOR_SIZE; part->total_blocks = (u32)part->mbd.mtd->size / part->block_size; if (part->total_blocks < 2) return -ENOENT; /* each erase block has three bytes header, followed by the map */ part->header_sectors_per_block = ((HEADER_MAP_OFFSET + sectors_per_block) * sizeof(u16) + SECTOR_SIZE - 1) / SECTOR_SIZE; part->data_sectors_per_block = sectors_per_block - part->header_sectors_per_block; part->header_size = (HEADER_MAP_OFFSET + part->data_sectors_per_block) * sizeof(u16); part->cylinders = (part->data_sectors_per_block * (part->total_blocks - 1) - 1) / SECTORS_PER_TRACK; part->sector_count = part->cylinders * SECTORS_PER_TRACK; part->current_block = -1; part->reserved_block = -1; part->is_reclaiming = 0; part->header_cache = kmalloc(part->header_size, GFP_KERNEL); if (!part->header_cache) goto err; part->blocks = kcalloc(part->total_blocks, sizeof(struct block), GFP_KERNEL); if (!part->blocks) goto err; part->sector_map = vmalloc(part->sector_count * sizeof(u_long)); if (!part->sector_map) { printk(KERN_ERR PREFIX "'%s': unable to allocate memory for " "sector map", part->mbd.mtd->name); goto err; } for (i=0; i<part->sector_count; i++) part->sector_map[i] = -1; for (i=0, blocks_found=0; i<part->total_blocks; i++) { rc = mtd_read(part->mbd.mtd, i * part->block_size, part->header_size, &retlen, (u_char *)part->header_cache); if (!rc && retlen != part->header_size) rc = -EIO; if (rc) goto err; if (!build_block_map(part, i)) blocks_found++; } if (blocks_found == 0) { printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n", part->mbd.mtd->name); rc = -ENOENT; goto err; } if (part->reserved_block == -1) { printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n", part->mbd.mtd->name); part->errors = 1; } return 0; err: vfree(part->sector_map); kfree(part->header_cache); kfree(part->blocks); return rc; }

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sean youngsean young44799.11%250.00%
adrian hunteradrian hunter30.67%125.00%
artem bityutskiyartem bityutskiy10.22%125.00%
Total451100.00%4100.00%


static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf) { struct partition *part = (struct partition*)dev; u_long addr; size_t retlen; int rc; if (sector >= part->sector_count) return -EIO; addr = part->sector_map[sector]; if (addr != -1) { rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen, (u_char *)buf); if (!rc && retlen != SECTOR_SIZE) rc = -EIO; if (rc) { printk(KERN_WARNING PREFIX "error reading '%s' at " "0x%lx\n", part->mbd.mtd->name, addr); return rc; } } else memset(buf, 0, SECTOR_SIZE); return 0; }

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sean youngsean young13999.29%150.00%
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Total140100.00%2100.00%


static void erase_callback(struct erase_info *erase) { struct partition *part; u16 magic; int i, rc; size_t retlen; part = (struct partition*)erase->priv; i = (u32)erase->addr / part->block_size; if (i >= part->total_blocks || part->blocks[i].offset != erase->addr || erase->addr > UINT_MAX) { printk(KERN_ERR PREFIX "erase callback for unknown offset %llx " "on '%s'\n", (unsigned long long)erase->addr, part->mbd.mtd->name); return; } if (erase->state != MTD_ERASE_DONE) { printk(KERN_WARNING PREFIX "erase failed at 0x%llx on '%s', " "state %d\n", (unsigned long long)erase->addr, part->mbd.mtd->name, erase->state); part->blocks[i].state = BLOCK_FAILED; part->blocks[i].free_sectors = 0; part->blocks[i].used_sectors = 0; kfree(erase); return; } magic = cpu_to_le16(RFD_MAGIC); part->blocks[i].state = BLOCK_ERASED; part->blocks[i].free_sectors = part->data_sectors_per_block; part->blocks[i].used_sectors = 0; part->blocks[i].erases++; rc = mtd_write(part->mbd.mtd, part->blocks[i].offset, sizeof(magic), &retlen, (u_char *)&magic); if (!rc && retlen != sizeof(magic)) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "'%s': unable to write RFD " "header at 0x%lx\n", part->mbd.mtd->name, part->blocks[i].offset); part->blocks[i].state = BLOCK_FAILED; } else part->blocks[i].state = BLOCK_OK; kfree(erase); }

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sean youngsean young28895.05%240.00%
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artem bityutskiyartem bityutskiy10.33%120.00%
harvey harrisonharvey harrison10.33%120.00%
Total303100.00%5100.00%


static int erase_block(struct partition *part, int block) { struct erase_info *erase; int rc = -ENOMEM; erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL); if (!erase) goto err; erase->mtd = part->mbd.mtd; erase->callback = erase_callback; erase->addr = part->blocks[block].offset; erase->len = part->block_size; erase->priv = (u_long)part; part->blocks[block].state = BLOCK_ERASING; part->blocks[block].free_sectors = 0; rc = mtd_erase(part->mbd.mtd, erase); if (rc) { printk(KERN_ERR PREFIX "erase of region %llx,%llx on '%s' " "failed\n", (unsigned long long)erase->addr, (unsigned long long)erase->len, part->mbd.mtd->name); kfree(erase); } err: return rc; }

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sean youngsean young15297.44%250.00%
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artem bityutskiyartem bityutskiy10.64%125.00%
Total156100.00%4100.00%


static int move_block_contents(struct partition *part, int block_no, u_long *old_sector) { void *sector_data; u16 *map; size_t retlen; int i, rc = -ENOMEM; part->is_reclaiming = 1; sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL); if (!sector_data) goto err3; map = kmalloc(part->header_size, GFP_KERNEL); if (!map) goto err2; rc = mtd_read(part->mbd.mtd, part->blocks[block_no].offset, part->header_size, &retlen, (u_char *)map); if (!rc && retlen != part->header_size) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error reading '%s' at " "0x%lx\n", part->mbd.mtd->name, part->blocks[block_no].offset); goto err; } for (i=0; i<part->data_sectors_per_block; i++) { u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]); u_long addr; if (entry == SECTOR_FREE || entry == SECTOR_DELETED) continue; if (entry == SECTOR_ZERO) entry = 0; /* already warned about and ignored in build_block_map() */ if (entry >= part->sector_count) continue; addr = part->blocks[block_no].offset + (i + part->header_sectors_per_block) * SECTOR_SIZE; if (*old_sector == addr) { *old_sector = -1; if (!part->blocks[block_no].used_sectors--) { rc = erase_block(part, block_no); break; } continue; } rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen, sector_data); if (!rc && retlen != SECTOR_SIZE) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "'%s': Unable to " "read sector for relocation\n", part->mbd.mtd->name); goto err; } rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part, entry, sector_data); if (rc) goto err; } err: kfree(map); err2: kfree(sector_data); err3: part->is_reclaiming = 0; return rc; }

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sean youngsean young37299.47%266.67%
artem bityutskiyartem bityutskiy20.53%133.33%
Total374100.00%3100.00%


static int reclaim_block(struct partition *part, u_long *old_sector) { int block, best_block, score, old_sector_block; int rc; /* we have a race if sync doesn't exist */ mtd_sync(part->mbd.mtd); score = 0x7fffffff; /* MAX_INT */ best_block = -1; if (*old_sector != -1) old_sector_block = *old_sector / part->block_size; else old_sector_block = -1; for (block=0; block<part->total_blocks; block++) { int this_score; if (block == part->reserved_block) continue; /* * Postpone reclaiming if there is a free sector as * more removed sectors is more efficient (have to move * less). */ if (part->blocks[block].free_sectors) return 0; this_score = part->blocks[block].used_sectors; if (block == old_sector_block) this_score--; else { /* no point in moving a full block */ if (part->blocks[block].used_sectors == part->data_sectors_per_block) continue; } this_score += part->blocks[block].erases; if (this_score < score) { best_block = block; score = this_score; } } if (best_block == -1) return -ENOSPC; part->current_block = -1; part->reserved_block = best_block; pr_debug("reclaim_block: reclaiming block #%d with %d used " "%d free sectors\n", best_block, part->blocks[best_block].used_sectors, part->blocks[best_block].free_sectors); if (part->blocks[best_block].used_sectors) rc = move_block_contents(part, best_block, old_sector); else rc = erase_block(part, best_block); return rc; }

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sean youngsean young26599.62%150.00%
artem bityutskiyartem bityutskiy10.38%150.00%
Total266100.00%2100.00%

/* * IMPROVE: It would be best to choose the block with the most deleted sectors, * because if we fill that one up first it'll have the most chance of having * the least live sectors at reclaim. */
static int find_free_block(struct partition *part) { int block, stop; block = part->current_block == -1 ? jiffies % part->total_blocks : part->current_block; stop = block; do { if (part->blocks[block].free_sectors && block != part->reserved_block) return block; if (part->blocks[block].state == BLOCK_UNUSED) erase_block(part, block); if (++block >= part->total_blocks) block = 0; } while (block != stop); return -1; }

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sean youngsean young106100.00%2100.00%
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static int find_writable_block(struct partition *part, u_long *old_sector) { int rc, block; size_t retlen; block = find_free_block(part); if (block == -1) { if (!part->is_reclaiming) { rc = reclaim_block(part, old_sector); if (rc) goto err; block = find_free_block(part); } if (block == -1) { rc = -ENOSPC; goto err; } } rc = mtd_read(part->mbd.mtd, part->blocks[block].offset, part->header_size, &retlen, (u_char *)part->header_cache); if (!rc && retlen != part->header_size) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "'%s': unable to read header at " "0x%lx\n", part->mbd.mtd->name, part->blocks[block].offset); goto err; } part->current_block = block; err: return rc; }

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sean youngsean young16999.41%266.67%
artem bityutskiyartem bityutskiy10.59%133.33%
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static int mark_sector_deleted(struct partition *part, u_long old_addr) { int block, offset, rc; u_long addr; size_t retlen; u16 del = cpu_to_le16(SECTOR_DELETED); block = old_addr / part->block_size; offset = (old_addr % part->block_size) / SECTOR_SIZE - part->header_sectors_per_block; addr = part->blocks[block].offset + (HEADER_MAP_OFFSET + offset) * sizeof(u16); rc = mtd_write(part->mbd.mtd, addr, sizeof(del), &retlen, (u_char *)&del); if (!rc && retlen != sizeof(del)) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error writing '%s' at " "0x%lx\n", part->mbd.mtd->name, addr); goto err; } if (block == part->current_block) part->header_cache[offset + HEADER_MAP_OFFSET] = del; part->blocks[block].used_sectors--; if (!part->blocks[block].used_sectors && !part->blocks[block].free_sectors) rc = erase_block(part, block); err: return rc; }

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sean youngsean young20999.05%250.00%
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harvey harrisonharvey harrison10.47%125.00%
Total211100.00%4100.00%


static int find_free_sector(const struct partition *part, const struct block *block) { int i, stop; i = stop = part->data_sectors_per_block - block->free_sectors; do { if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]) == SECTOR_FREE) return i; if (++i == part->data_sectors_per_block) i = 0; } while(i != stop); return -1; }

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sean youngsean young81100.00%1100.00%
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static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr) { struct partition *part = (struct partition*)dev; struct block *block; u_long addr; int i; int rc; size_t retlen; u16 entry; if (part->current_block == -1 || !part->blocks[part->current_block].free_sectors) { rc = find_writable_block(part, old_addr); if (rc) goto err; } block = &part->blocks[part->current_block]; i = find_free_sector(part, block); if (i < 0) { rc = -ENOSPC; goto err; } addr = (i + part->header_sectors_per_block) * SECTOR_SIZE + block->offset; rc = mtd_write(part->mbd.mtd, addr, SECTOR_SIZE, &retlen, (u_char *)buf); if (!rc && retlen != SECTOR_SIZE) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n", part->mbd.mtd->name, addr); goto err; } part->sector_map[sector] = addr; entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector); part->header_cache[i + HEADER_MAP_OFFSET] = entry; addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16); rc = mtd_write(part->mbd.mtd, addr, sizeof(entry), &retlen, (u_char *)&entry); if (!rc && retlen != sizeof(entry)) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n", part->mbd.mtd->name, addr); goto err; } block->used_sectors++; block->free_sectors--; err: return rc; }

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sean youngsean young33099.40%266.67%
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static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf) { struct partition *part = (struct partition*)dev; u_long old_addr; int i; int rc = 0; pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector); if (part->reserved_block == -1) { rc = -EACCES; goto err; } if (sector >= part->sector_count) { rc = -EIO; goto err; } old_addr = part->sector_map[sector]; for (i=0; i<SECTOR_SIZE; i++) { if (!buf[i]) continue; rc = do_writesect(dev, sector, buf, &old_addr); if (rc) goto err; break; } if (i == SECTOR_SIZE) part->sector_map[sector] = -1; if (old_addr != -1) rc = mark_sector_deleted(part, old_addr); err: return rc; }

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static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) { struct partition *part = (struct partition*)dev; geo->heads = 1; geo->sectors = SECTORS_PER_TRACK; geo->cylinders = part->cylinders; return 0; }

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static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) { struct partition *part; if (mtd->type != MTD_NORFLASH || mtd->size > UINT_MAX) return; part = kzalloc(sizeof(struct partition), GFP_KERNEL); if (!part) return; part->mbd.mtd = mtd; if (block_size) part->block_size = block_size; else { if (!mtd->erasesize) { printk(KERN_WARNING PREFIX "please provide block_size"); goto out; } else part->block_size = mtd->erasesize; } if (scan_header(part) == 0) { part->mbd.size = part->sector_count; part->mbd.tr = tr; part->mbd.devnum = -1; if (!(mtd->flags & MTD_WRITEABLE)) part->mbd.readonly = 1; else if (part->errors) { printk(KERN_WARNING PREFIX "'%s': errors found, " "setting read-only\n", mtd->name); part->mbd.readonly = 1; } printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n", mtd->name, mtd->type, mtd->flags); if (!add_mtd_blktrans_dev((void*)part)) return; } out: kfree(part); }

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adrian hunteradrian hunter62.75%120.00%
andrew mortonandrew morton52.29%120.00%
robert p. j. dayrobert p. j. day10.46%120.00%
Total218100.00%5100.00%


static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev) { struct partition *part = (struct partition*)dev; int i; for (i=0; i<part->total_blocks; i++) { pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n", part->mbd.mtd->name, i, part->blocks[i].erases); } del_mtd_blktrans_dev(dev); vfree(part->sector_map); kfree(part->header_cache); kfree(part->blocks); }

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sean youngsean young93100.00%1100.00%
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static struct mtd_blktrans_ops rfd_ftl_tr = { .name = "rfd", .major = RFD_FTL_MAJOR, .part_bits = PART_BITS, .blksize = SECTOR_SIZE, .readsect = rfd_ftl_readsect, .writesect = rfd_ftl_writesect, .getgeo = rfd_ftl_getgeo, .add_mtd = rfd_ftl_add_mtd, .remove_dev = rfd_ftl_remove_dev, .owner = THIS_MODULE, };
static int __init init_rfd_ftl(void) { return register_mtd_blktrans(&rfd_ftl_tr); }

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static void __exit cleanup_rfd_ftl(void) { deregister_mtd_blktrans(&rfd_ftl_tr); }

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module_init(init_rfd_ftl); module_exit(cleanup_rfd_ftl); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Sean Young <sean@mess.org>"); MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, " "used by General Software's Embedded BIOS");

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sean youngsean young363698.38%317.65%
adrian hunteradrian hunter250.68%15.88%
artem bityutskiyartem bityutskiy110.30%423.53%
andrew mortonandrew morton80.22%211.76%
richard purdierichard purdie50.14%15.88%
paul gortmakerpaul gortmaker30.08%15.88%
tim schmielautim schmielau30.08%15.88%
harvey harrisonharvey harrison20.05%15.88%
david woodhousedavid woodhouse10.03%15.88%
robert p. j. dayrobert p. j. day10.03%15.88%
adrian bunkadrian bunk10.03%15.88%
Total3696100.00%17100.00%
Directory: drivers/mtd
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