> > On Tue, Dec 01, 2009 at 01:06:07PM -0500, [email protected] wrote: > > +MTD NAND 64 bit support: > > +======================== > > + > > +The MTD NAND infrastructure in U-Boot(until release 2009.11) used only > > +32 bit values to represent device size. As a result of which if we use > > +a NAND device of size 4 GB and above, the MTD NAND driver will not > detect > > +such a NAND device due to overflow. > > +NANDs comes in various flavours. There are some NANDs which are > > +internally 2 devices and have 2 chipselects. If the SOC specific > > +NAND driver is designed to treat each NAND device as a separate device > > +then we will still be able to detect the entire 4GB of a NAND device. > > +Each chipselect being responsible for 2 GB address space. > > +But if at the U-Boot level we want to have access to the entire 4GB > address > > +space then the only way to achieve this is to update the MTD and NAND > drivers > > +with 64 bit values. > > +The Linux kernel was updated with 64 bit values sometime in December > '08. > > +The core NAND driver is now similar to the core NAND driver in the > kernel. > > +We appropriately update the MTD layer in U-Boot. > > +In the process of syncing up with the kernel we have also updated the > > +NAND driver with other enhancements that made its way to the NAND > driver. > > + > > +After these features were added, testing was performed on a wide > > +range of NAND devices with page size of 64 KiB, 128KiB, 256KiB and 512 > > +KiB. Also 2 separate 4GB NAND devices(one from SAMSUNG and one from > MICRON) > > +were successfully tested. U-Boot was able to correctly detect the > device > > +and read bad blocks. > > Hmm, not sure we need to describe here what was, rather than what is.
Let me know what parts you want removed. I just decided to put as much info as possible with a little history as well. > > > +What is lacking? > > +================ > > + > > +We need to add 64 bit support in cmd_nand.c and env_nand.c as well. > > +Without this certain diagnostcis > > typo > > > will fail. For example, > > +issuing a "nand bad" command results in the same bad blocks being > > +found infinite times. This happens if we use a 4 GB NAND device. > > +This will not occur if NANDs of smalles than 4 GB are used. > > s/of smalles than/smaller than/ I'll fix the typos > > > +At this point of time it appears as if the entire common folder > > +needs to be updated with 64 bit values. > > Yeah... If you want to put a concise note about this here, I'll add it, > though an actual bug tracking system would be nice. :-) Again let me know what sections are not required. > > -Scott I'll send an updated patch after your reply. Sandeep _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
