Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [RFC][PATCH] misc: Introduce reboot_reason driver | Date | Thu, 10 Dec 2015 10:05:33 +0100 |
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On Wednesday 09 December 2015 17:32:02 John Stultz wrote: > On Tue, Dec 8, 2015 at 2:07 PM, Bjorn Andersson > <bjorn.andersson@sonymobile.com> wrote: > > On Tue 08 Dec 13:29 PST 2015, John Stultz wrote: > >> diff --git a/arch/arm/boot/dts/qcom-apq8064-nexus7-flo.dts b/arch/arm/boot/dts/qcom-apq8064-nexus7-flo.dts > >> index 5183d18..ee5dcb7 100644 > >> --- a/arch/arm/boot/dts/qcom-apq8064-nexus7-flo.dts > >> +++ b/arch/arm/boot/dts/qcom-apq8064-nexus7-flo.dts > >> @@ -282,6 +282,15 @@ > >> }; > >> }; > >> > >> + reboot_reason: reboot_reason@2a03f65c { > >> + compatible = "reboot_reason"; > >> + reg = <0x2A03F65C 0x4>; > >> + reason,none = <0x77665501>; > >> + reason,bootloader = <0x77665500>; > >> + reason,recovery = <0x77665502>; > >> + reason,oem = <0x6f656d00>; > >> + }; > >> + > > > > This address refers to IMEM, which is shared with a number of other > > uses. So I think we should have a simple-mfd (and syscon) with this > > within. > > So talking with Arnd some more it looked like IMEM was really just > SRAM. Is that not the case, or is there something else special about > it? Does it really need simple-mfd and syscon? I'm still fuzzy on how > to use those for this.
If it's SRAM, we should use the SRAM binding and not make it a syscon device. What we can have however, is a mostly somewhat reboot-reason driver that is able to access an SRAM device or something else, depending on what the platform and/or bootloader has.
HTC's Nexus 9 apparently uses a section of normal RAM for communication between bootloader and kernel, so we'd also need a way to hook into a driver for that.
Arnd
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