On 11/11/2016 05:42 AM, Joel Stanley wrote: > On Wed, Nov 9, 2016 at 9:12 PM, Cédric Le Goater <clg@xxxxxxxx> 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 > > It's also in use on the Zaius and Barreleye OpenBMC systems. > > In that respect, I would like to see this merged once it's deemed > ready by the mtd maintainers. We can follow up with the extra features > in future patches. > > I've reviewed and tested this as Cedric and Milton have developed it, > so please add: > > Reviewed-by: Joel Stanley <joel@xxxxxxxxx> > Thanks! I'll review the patch ASAP (this week). -- Best regards, Marek Vasut -- 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
