将整个device的分区情况存在一个BLock中，这样BootLoader启动的时候，根据这个BLock中的内容建立相应信息等。好像只有Red Boot支持。所以叫RedBoot Partition Table。另外，LK可以识别这种分区，通过CFI（Command Flash Interface）读取这个分区的信息。
Kernel Command Line Partitioning:通过Kernel启动的时候传入参数，不过KL必须配置一下。Command格式如下：
图2
再看看Driver的Mapping，也就是将MTD和对应的Flash Driver配对...
kernel/drivers/mtd/maps......，以后要分析
Flash芯片本身的Driver呢？
kernel/drivers/mtd/chips，目前比较流行的是CFI接口
三 一些参考资料和补充知识
MTD的本意是：
We're working on a generic Linux subsystem for memory devices, especially Flash devices.
The aim of the system is to make it simple to provide a driver for new hardware, by providing a generic interface between the hardware drivers and the upper layers of the system.
Hardware drivers need to know nothing about the storage formats used, such as FTL, FFS2, etc., but will only need to provide simple routines for read, write and erase. Presentation of the device's contents to the user in an appropriate form will be handled by the upper layers of the system.
MTD overview
MTD subsystem (stands for Memory Technology Devices) provides an abstraction layer for raw flash devices. It makes it possible to use the same API when working with different flash types and technologies, e.g. NAND, OneNAND, NOR, AG-AND, ECC'd NOR, etc.
MTD subsystem does not deal with block devices like MMC, eMMC, SD, CompactFlash, etc. These devices are not raw flashes but they have a Flash Translation layer inside, which makes them look like block devices. These devices are the subject of the Linux block subsystem, not MTD. Please, refer to this FAQ section for a short list of the main differences between block and MTD devices. And the raw flash vs. FTL devices UBIFS section discusses this in more details.
MTD subsystem has the following interfaces.
MTD subsystem supports bare NAND flashes with software and hardware ECC, OneNAND flashes, CFI (Common Flash Interface) NOR flashes, and other flash types.
Additionally, MTD supports legacy FTL/NFTL "translation layers", M-Systems' DiskOnChip 2000 and Millennium chips, and PCMCIA flashes (pcmciamtd driver). But the corresponding drivers are very old and not maintained very much.
MTD Block Driver:
The mtdblock driver available in the MTD is an archaic tool which emulates block devices on top of MTD devices. It does not even have bad eraseblock handling, so it is not really usable with NAND flashes. And it works by caching a whole flash erase block in RAM, modifying it as requested, then erasing the whole block and writing back the modified. This means that mtdblock does not try to do any optimizations, and that you will lose lots of data in case of power cuts. And last, but not least, mtdblock does not do any wear-leveling.
Often people consider mtdblock as general FTL layer and try to use block-based file systems on top of bare flashes using mtdblock. This is wrong in most cases. In other words, please, do not use mtdblock unless you know exactly what you are doing.
There is also a read-only version of this driver which doesn't have the capacity to do the caching and erase/writeback, mainly for use with uCLinux where the extra RAM requirement was considered too large
These are the modules which provide interfaces that can be used directly from userspace. The user modules currently planned include:
这里牵扯到NOR和NAND，那么二者有啥区别呢？