--- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -21,6 +21,8 @@ #include <linux/root_dev.h> #include <linux/magic.h> +#define MTD_ERASE_PARTIAL 0x8000 /* partition only covers parts of an erase block */ + /* Our partition linked list */ static LIST_HEAD(mtd_partitions); @@ -228,13 +230,60 @@ static int part_erase(struct mtd_info *m return -EROFS; if (instr->addr >= mtd->size) return -EINVAL; + + instr->partial_start = false; + if (mtd->flags & MTD_ERASE_PARTIAL) { + size_t readlen = 0; + u64 mtd_ofs; + + instr->erase_buf = kmalloc(part->master->erasesize, GFP_ATOMIC); + if (!instr->erase_buf) + return -ENOMEM; + + mtd_ofs = part->offset + instr->addr; + instr->erase_buf_ofs = do_div(mtd_ofs, part->master->erasesize); + + if (instr->erase_buf_ofs > 0) { + instr->addr -= instr->erase_buf_ofs; + ret = part->master->read(part->master, + instr->addr + part->offset, + part->master->erasesize, + &readlen, instr->erase_buf); + + instr->partial_start = true; + } else { + mtd_ofs = part->offset + part->mtd.size; + instr->erase_buf_ofs = part->master->erasesize - + do_div(mtd_ofs, part->master->erasesize); + + if (instr->erase_buf_ofs > 0) { + instr->len += instr->erase_buf_ofs; + ret = part->master->read(part->master, + part->offset + instr->addr + + instr->len - part->master->erasesize, + part->master->erasesize, &readlen, + instr->erase_buf); + } else { + ret = 0; + } + } + if (ret < 0) { + kfree(instr->erase_buf); + return ret; + } + + } + instr->addr += part->offset; ret = part->master->erase(part->master, instr); if (ret) { if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN) instr->fail_addr -= part->offset; instr->addr -= part->offset; + if (mtd->flags & MTD_ERASE_PARTIAL) + kfree(instr->erase_buf); } + return ret; } @@ -242,7 +291,25 @@ void mtd_erase_callback(struct erase_inf { if (instr->mtd->erase == part_erase) { struct mtd_part *part = PART(instr->mtd); + size_t wrlen = 0; + if (instr->mtd->flags & MTD_ERASE_PARTIAL) { + if (instr->partial_start) { + part->master->write(part->master, + instr->addr, instr->erase_buf_ofs, + &wrlen, instr->erase_buf); + instr->addr += instr->erase_buf_ofs; + } else { + instr->len -= instr->erase_buf_ofs; + part->master->write(part->master, + instr->addr + instr->len, + instr->erase_buf_ofs, &wrlen, + instr->erase_buf + + part->master->erasesize - + instr->erase_buf_ofs); + } + kfree(instr->erase_buf); + } if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN) instr->fail_addr -= part->offset; instr->addr -= part->offset; @@ -476,18 +543,24 @@ static struct mtd_part *add_one_partitio if ((slave->mtd.flags & MTD_WRITEABLE) && mtd_mod_by_eb(slave->offset, &slave->mtd)) { /* Doesn't start on a boundary of major erase size */ - /* FIXME: Let it be writable if it is on a boundary of - * _minor_ erase size though */ - slave->mtd.flags &= ~MTD_WRITEABLE; - printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n", - part->name); + slave->mtd.flags |= MTD_ERASE_PARTIAL; + if (((u32) slave->mtd.size) > master->erasesize) + slave->mtd.flags &= ~MTD_WRITEABLE; + else + slave->mtd.erasesize = slave->mtd.size; } if ((slave->mtd.flags & MTD_WRITEABLE) && - mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) { - slave->mtd.flags &= ~MTD_WRITEABLE; - printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n", - part->name); - } + mtd_mod_by_eb(slave->offset + slave->mtd.size, &slave->mtd)) { + slave->mtd.flags |= MTD_ERASE_PARTIAL; + + if ((u32) slave->mtd.size > master->erasesize) + slave->mtd.flags &= ~MTD_WRITEABLE; + else + slave->mtd.erasesize = slave->mtd.size; + } + if ((slave->mtd.flags & (MTD_ERASE_PARTIAL|MTD_WRITEABLE)) == MTD_ERASE_PARTIAL) + printk(KERN_WARNING"mtd: partition \"%s\" must either start or end on erase block boundary or be smaller than an erase block -- forcing read-only\n", + part->name); slave->mtd.ecclayout = master->ecclayout; if (master->block_isbad) { --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -46,6 +46,10 @@ struct erase_info { u_long priv; u_char state; struct erase_info *next; + + u8 *erase_buf; + u32 erase_buf_ofs; + bool partial_start; }; struct mtd_erase_region_info {