On Wed, Nov 09, 2016 at 11:42:29AM +0100, Cédric Le Goater wrote: > This driver adds mtd support for spi-nor attached to either or both of > the Firmware Memory Controller or the SPI Flash Controller (AST2400 > only). > > The SMC controllers on the Aspeed AST2500 SoC are very similar to the > ones found on the AST2400. The differences are on the number of > supported flash modules and their default mappings in the SoC address > space. > > The Aspeed AST2500 has one SPI controller for the BMC firmware and two > for the host firmware. All controllers have now the same set of > registers compatible with the AST2400 FMC controller and the legacy > 'SMC' controller is fully gone. > > Each controller has a memory range on which it maps its flash module > slaves. Each slave is assigned a memory window for its mapping that > can be changed at bootime with the Segment Address Register. > > Each SPI flash slave can then be accessed in two modes: Command and > User. When in User mode, accesses to the memory segment of the slaves > are translated in SPI transfers. When in Command mode, the HW > generates the SPI commands automatically and the memory segment is > accessed as if doing a MMIO. > > Currently, only the User mode is supported. Command mode needs a > little more work to check that the memory window on the AHB bus fits > the module size. > > Based on previous work from Milton D. Miller II <miltonm@xxxxxxxxxx> > > Signed-off-by: Cédric Le Goater <clg@xxxxxxxx> > --- > Tested on: > > * OpenPOWER Palmetto (AST2400) with > FMC controller : n25q256a > SPI controller : mx25l25635e and n25q512ax3 > > * Evaluation board (AST2500) with > FMC controller : w25q256 > SPI controller : w25q256 > > * OpenPOWER Witherspoon (AST2500) with > FMC controller : mx25l25635e * 2 > SPI controller : mx66l1g45g > > Changes since v2: > > - added a set4b ops to handle difference in the controllers > - simplified the IO routines > - prepared for fast read using dummy cycles > > Work in progress: > > - read optimization using higher SPI clock frequencies > - command mode to direct reads from AHB > - DMA support > > .../devicetree/bindings/mtd/aspeed-smc.txt | 72 ++ Acked-by: Rob Herring <robh@xxxxxxxxxx> > drivers/mtd/spi-nor/Kconfig | 12 + > drivers/mtd/spi-nor/Makefile | 1 + > drivers/mtd/spi-nor/aspeed-smc.c | 783 +++++++++++++++++++++ > 4 files changed, 868 insertions(+) > create mode 100644 Documentation/devicetree/bindings/mtd/aspeed-smc.txt > create mode 100644 drivers/mtd/spi-nor/aspeed-smc.c -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
