Russell/Johan, On 08/01/2017 01:08 PM, Santosh Shilimkar wrote: > On 7/26/2017 9:54 AM, Santosh Shilimkar wrote: >> >> On 7/24/2017 2:24 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 making use of the ARM >>> asm-offsets file. In the same header that we define our data structures >>> in we also define all the macros in an inline function and by adding a >>> call to this in the asm_offsets file all macros are properly generated >>> and available to the assembly code without cluttering up the asm-offsets >>> file. >>> >>> Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx> >>> --- > [...] > >>> >>> arch/arm/kernel/asm-offsets.c | 4 + >>> drivers/memory/Kconfig | 10 ++ >>> drivers/memory/Makefile | 4 + >>> drivers/memory/emif.h | 17 ++ >>> drivers/memory/ti-emif-pm.c | 339 >>> +++++++++++++++++++++++++++++++++++++++ >>> drivers/memory/ti-emif-sram-pm.S | 334 >>> ++++++++++++++++++++++++++++++++++++++ >>> include/linux/ti-emif-sram.h | 147 +++++++++++++++++ >>> 7 files changed, 855 insertions(+) >>> create mode 100644 drivers/memory/ti-emif-pm.c >>> create mode 100644 drivers/memory/ti-emif-sram-pm.S >>> create mode 100644 include/linux/ti-emif-sram.h >>> >> I will need RMKs blessing since he reviewed the ASM code. >> >> Also need work out how to line this up. Typically I use to get >> driver/memory patches via Greg's driver-core but this is more >> PM code than memory driver and very SOC specific. >> >> Hi Arnd/Olof, >> Will you be ok to pull this via arm-soc ? There is also follow >> up platform PM code and DTS series which will make use of this. >> > Looks like I missed to copy Olof. Let me know guys if you are > ok to pull this into your driver-soc given the dependencies. Any additional comments here? I believe I have addressed everything from v2 so hopefully this is acceptable now. Regards, Dave > > Regards > Santosh > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
