On Mon, Oct 16, 2017 at 08:31:59AM -0700, Santosh Shilimkar wrote: > Hi Russell, > > On 10/13/2017 1:59 PM, Dave Gerlach wrote: > >Certain SoCs like Texas Instruments AM335x and AM437x require parts > >of the EMIF PM code to run late in the suspend sequence from SRAM, > >such as saving and restoring the EMIF context and placing the memory > >into self-refresh. > > > >One requirement for these SoCs to suspend and enter its lowest power > >mode, called DeepSleep0, is that the PER power domain must be shut off. > >Because the EMIF (DDR Controller) resides within this power domain, it > >will lose context during a suspend operation, so we must save it so we > >can restore once we resume. However, we cannot execute this code from > >external memory, as it is not available at this point, so the code must > >be executed late in the suspend path from SRAM. > > > >This patch introduces a ti-emif-sram driver that includes several > >functions written in ARM ASM that are relocatable so the PM SRAM > >code can use them. It also allocates a region of writable SRAM to > >be used by the code running in the executable region of SRAM to save > >and restore the EMIF context. It can export a table containing the > >absolute addresses of the available PM functions so that other SRAM > >code can branch to them. This code is required for suspend/resume on > >AM335x and AM437x to work. > > > >In addition to this, to be able to share data structures between C and > >the ti-emif-sram-pm assembly code, we can automatically generate all of > >the C struct member offsets and sizes as macros by processing > >emif-asm-offsets.c into assembly code and then extracting the relevant > >data as is done for the generated platform asm-offsets.h files. > > > >Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx> > >--- > >v4->v5: > >* Simplify Makefile to generate include/generated/ti-emif-asm-offsets.h > > > If you are happy with this version from Dave, can I get your ack please? > I can add this to the driver-soc then. Does it need my ack anymore? It doesn't touch anything in arch/arm. If you still want it, then... notwithstanding the loss of type checking that fncpy() gave and the new sram stuff messes up... Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up -- 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
