Hi Thomas, On 6 November 2015 at 05:48, Thomas Chou <[email protected]> wrote: > Hi Jagan, > > On 2015年11月05日 22:57, Jagan Teki wrote: >> >> The altera quad spi core is very special that the hardware handle the >>> >>> spi-nor protocol. The core is designed to replace the CFI flash >>> interface. >>> So there is nothing to do with SPI from the parallel flash interface. It >>> is >>> memory mapped. There is no SPI interface. There is nothing related to SPI >>> programming. So please don't worry about the progress on spi-nor. The >>> core >>> should belong to parallel flash, but not serial flash. >> >> >> Agreed that this is not doing any generic spi things, but it's a >> spi-nor controller all spi-nor controller should be part of spi-nor >> subsystem Linux agreed and have a framework for that. >> >> drivers/mtd/spi-nor/fsl-quadspi.c >> drivers/mtd/spi-nor/nxp-spifi.c >> >> all these are spi-nor controller which doesn't do any generic spi >> things but should be in spi-nor subsystem. Even Marek send altera_qspi >> as spi-nor controller [1] >> >> Since I'm working on similar spi-nor subsystem what Linux have + >> driver model little worried about this because once we have spi-nor >> again it should be a re-work. >> >> [1] http://lists.infradead.org/pipermail/linux-mtd/2015-April/058650.html > > > I had been a hardware engineer. I designed chips and boards. I believe this > should depend on the programming interface. Eg, there are SSDs of SATA > interfaces which build with NAND or EMMC, and it dose not make sense to > classify them as NAND or MMC. The altera quadspi core is a similar case, > because the hardware converts the programming interface. There is no way to > send spi-nor commands that the spi frame work does. It is ridiculous to > insist it to use under the spi-nor framework.
I appreciate your hardware expertise and am not questioning about that as well. I do agree with the hw logic about altera qspi controller and I don't have any questions with hw either. But my main intention here was about the software support since Linux discussed about this subject and finally moved to spi-nor controllers (though they don't use spi bus at-all) to spi-nor framework and Marek knows this topic very well. I believe discussion about this topic much more clear if we send this driver to Linux. > > The altera quadspi hides details about the underlying spi-nor. We may even > choose to build interface that convert EMMC to like cfi flash. The users can > run code directly on the flash or use memory command like "cp.b" of u-boot > to program the flash. This can be a advantage over the "sf" command. thanks! -- Jagan | openedev. _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
