| Message ID | 1454407151-4751-1-git-send-email-andy.yan@rock-chips.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Feb 2, 2016 at 1:59 AM, Andy Yan <andy.yan@rock-chips.com> wrote: > add device tree bindings document for reboot-mode driver > > Signed-off-by: Andy Yan <andy.yan@rock-chips.com> > > --- > > Changes in v3: > - descirbe all reboot mode as properity instead of subnode > > Changes in v2: None > Changes in v1: None > > .../bindings/power/reset/reboot-mode.txt | 26 ++++++++++++++++ > .../bindings/power/reset/syscon-reboot-mode.txt | 36 ++++++++++++++++++++++ > 2 files changed, 62 insertions(+) > create mode 100644 Documentation/devicetree/bindings/power/reset/reboot-mode.txt > create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt > > diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt > new file mode 100644 > index 0000000..517080f > --- /dev/null > +++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt > @@ -0,0 +1,26 @@ > +Generic reboot mode core map driver > + > +This driver get reboot mode arguments and call the write > +interface to stores the magic value in special register > +or ram . Then the bootloader can read it and take different > +action according the argument stored. > + > +All mode properties are vendor specific, it is a indication to tell > +the bootloder what to do when the system reboot, and should be named > +as mode-xxx = <magic> (xxx is mode name). > + > +- mode-normal: Normal reboot mode, system reboot with command "reboot". > +- mode-recovery: Android Recovery mode, it is a mode to format the device or update a new image. > +- mode-fastboot: Android fastboot mode, it's a mode to re-flash partitions on the device. One minor tweak here, on most Android devices (atleast most Nexus devices) getting to fastboot is done via "reboot bootloader" not "reboot fastboot". If we are going to document the commands here to establish a standard, I'd prefer we use use what existing userspace expects: So across nexus devices, there's really two consistent commands: "bootloader", and "recovery" Nexus 6p: https://android.googlesource.com/kernel/msm.git/+/android-msm-bullhead-3.10-marshmallow-mr1/drivers/power/reset/msm-poweroff.c#230 Nexus 9: https://android.googlesource.com/kernel/tegra.git/+/android-tegra-flounder-3.10-marshmallow-mr1/drivers/htc_debug/stability/reboot_params.c#86 Nexus 7: https://android.googlesource.com/kernel/msm.git/+/android-msm-flo-3.4-marshmallow-mr1/arch/arm/mach-msm/restart.c#273 Nexus 10: https://android.googlesource.com/kernel/exynos.git/+/android-exynos-manta-3.4-lollipop-mr1/arch/arm/mach-exynos/board-manta-power.c#422 While I don't object to having a duplicative mode-fastboot (it is more clear as to what the command does), or the other oem specific modes, I think we should make it clear that the Android userspace expects the "bootloader" and "recovery" commands and document them here. thanks -john
On Tue, Feb 02, 2016 at 05:59:11PM +0800, Andy Yan wrote: > add device tree bindings document for reboot-mode driver > > Signed-off-by: Andy Yan <andy.yan@rock-chips.com> > > --- > > Changes in v3: > - descirbe all reboot mode as properity instead of subnode > > Changes in v2: None > Changes in v1: None > > .../bindings/power/reset/reboot-mode.txt | 26 ++++++++++++++++ > .../bindings/power/reset/syscon-reboot-mode.txt | 36 ++++++++++++++++++++++ > 2 files changed, 62 insertions(+) > create mode 100644 Documentation/devicetree/bindings/power/reset/reboot-mode.txt > create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt > > diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt > new file mode 100644 > index 0000000..517080f > --- /dev/null > +++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt > @@ -0,0 +1,26 @@ > +Generic reboot mode core map driver > + > +This driver get reboot mode arguments and call the write > +interface to stores the magic value in special register > +or ram . Then the bootloader can read it and take different > +action according the argument stored. > + > +All mode properties are vendor specific, it is a indication to tell The values should be vendor specific. The property names should not. We can allow vendor specific ones, but we need to have a common set. > +the bootloder what to do when the system reboot, and should be named > +as mode-xxx = <magic> (xxx is mode name). > + > +- mode-normal: Normal reboot mode, system reboot with command "reboot". > +- mode-recovery: Android Recovery mode, it is a mode to format the device or update a new image. > +- mode-fastboot: Android fastboot mode, it's a mode to re-flash partitions on the device. > +- mode-loader: A bootloader mode, it's a mode used to download image on Rockchip platform, > + usually used in development. > +- mode-maskrom: It's a mode to download bootloader on Rockchip platform. > + > +Example: > + reboot-mode { > + mode-normal = <BOOT_NORMAL>; > + mode-recovery = <BOOT_RECOVERY>; > + mode-fastboot = <BOOT_FASTBOOT>; I tend to agree with John on calling this mode-bootloader. OTOH, fastboot is more specific about what the mode is. The name in DT and the userspace name don't necessarily have to be the same. > + mode-loader = <BOOT_LOADER>; This one needs a better name. Maybe it should be 'rockchip,mode-loader' as it is vendor specific. Either way, loader is vague. Perhaps rockchip,mode-bl-download? > + mode-maskrom = <BOOT_MASKROM>; I think this should be "mode-rom-download". > + } > diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt > new file mode 100644 > index 0000000..923c82b > --- /dev/null > +++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt > @@ -0,0 +1,36 @@ > +SYSCON reboot mode driver > + > +This driver get reboot mode magic value form reboot-mode driver > +and stores it in a SYSCON mapped register. Then the bootloader > +can read it and take different action according to the magic > +value stored. > + > +This DT node should be represented as a sub-node of a "syscon", "simple-mfd" > +node. Whether or not it is a simple-mfd or not depends on the syscon node. > + > +Required properties: > +- compatible: should be "syscon-reboot-mode" > +- offset: offset in the register map for the storage register (in bytes) > + > +Optional properity: > +- mask: the mask bits of the mode magic value, default set to 0xffffffff if missing. > + > +The rest of the properties should follow the generic reboot-mode discription > +found in reboot-mode.txt > + > +Example: > + pmu: pmu@20004000 { > + compatible = "rockchip,rk3066-pmu", "syscon", "simple-mfd"; > + reg = <0x20004000 0x100>; > + > + reboot-mode { > + compatible = "syscon-reboot-mode"; > + offset = <0x40>; > + mode-normal = <BOOT_NORMAL>; > + mode-recovery = <BOOT_RECOVERY>; > + mode-fastboot = <BOOT_FASTBOOT>; > + mode-loader = <BOOT_LOADER>; > + mode-maskrom = <BOOT_MASKROM>; > + > + }; > + }; > -- > 1.9.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Feb 4, 2016 at 3:08 PM, Rob Herring <robh@kernel.org> wrote: > On Tue, Feb 02, 2016 at 05:59:11PM +0800, Andy Yan wrote: >> add device tree bindings document for reboot-mode driver >> >> Signed-off-by: Andy Yan <andy.yan@rock-chips.com> >> >> --- >> >> Changes in v3: >> - descirbe all reboot mode as properity instead of subnode >> >> Changes in v2: None >> Changes in v1: None >> >> .../bindings/power/reset/reboot-mode.txt | 26 ++++++++++++++++ >> .../bindings/power/reset/syscon-reboot-mode.txt | 36 ++++++++++++++++++++++ >> 2 files changed, 62 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/power/reset/reboot-mode.txt >> create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt >> >> diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt >> new file mode 100644 >> index 0000000..517080f >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt >> @@ -0,0 +1,26 @@ >> +Generic reboot mode core map driver >> + >> +This driver get reboot mode arguments and call the write >> +interface to stores the magic value in special register >> +or ram . Then the bootloader can read it and take different >> +action according the argument stored. >> + >> +All mode properties are vendor specific, it is a indication to tell > > The values should be vendor specific. The property names should not. We > can allow vendor specific ones, but we need to have a common set. > >> +the bootloder what to do when the system reboot, and should be named >> +as mode-xxx = <magic> (xxx is mode name). >> + >> +- mode-normal: Normal reboot mode, system reboot with command "reboot". >> +- mode-recovery: Android Recovery mode, it is a mode to format the device or update a new image. >> +- mode-fastboot: Android fastboot mode, it's a mode to re-flash partitions on the device. >> +- mode-loader: A bootloader mode, it's a mode used to download image on Rockchip platform, >> + usually used in development. >> +- mode-maskrom: It's a mode to download bootloader on Rockchip platform. >> + >> +Example: >> + reboot-mode { >> + mode-normal = <BOOT_NORMAL>; >> + mode-recovery = <BOOT_RECOVERY>; >> + mode-fastboot = <BOOT_FASTBOOT>; > > I tend to agree with John on calling this mode-bootloader. > > OTOH, fastboot is more specific about what the mode is. The name in DT > and the userspace name don't necessarily have to be the same. Wait. This is a bit confusing. The utility of adding a property name and using that name be the reboot command parsed for made sense (compared to earlier versions which had command strings) as it made the dts more terse. But it sounds here like you're suggesting we should have some logic in the driver that translates "reboot fastboot" to mode-bootloader or vice versa. >> + mode-loader = <BOOT_LOADER>; > > This one needs a better name. Maybe it should be 'rockchip,mode-loader' > as it is vendor specific. Either way, loader is vague. Perhaps > rockchip,mode-bl-download? Hrm. So how what reboot command do you expect to trigger that? Though I do like the vendor specific prefix here, as it clarifies how universal the command is (and its easy add standard commands if they become more established and remap things in the future). > >> + mode-maskrom = <BOOT_MASKROM>; > > I think this should be "mode-rom-download". I think one of the difficult things here is that there's no real standards for all bios/bootloader modes. So they are somewhat firmware/bootloader/device specific, and thus we need something that is flexible enough to allow lots of different modes to be easily specified. That said, this does expose a userspace interface (though one could argue kernel ABI doesn't cross reboots :) so we should try to have some consistency so the same userspace can work on various devices. I do think the "bootloader" and "recovery" arguments are somewhat defacto standards, well established on most android devices. I think here the concern is rockchip probably has some userspace that is already using "reboot maskrom" or "reboot loader" for their own uses. And its a bit of a pain to ask that userspace to be reworked to use "reboot rom-download" or "reboot rockchip,rom-download" depending on how we try to deal with these. (Granted, non-upstream interfaces aren't official, so that is their risk somewhat, but we avoid being smug about that :) Another part of the issue is there isn't really a way to probe for reboot cmd capability here. As much as I'd rather not complicate things, one couldn't easily extend existing userspace to work with current kernels as well as future kernels, since the reboot with an invalid command won't fail. The machine still resets. So you can't try one and fallback to the other. Maybe there needs to be a sysfs entry with the list of the supported commands? thanks -john
On Thu, Feb 04, 2016 at 03:46:15PM -0800, John Stultz wrote: > On Thu, Feb 4, 2016 at 3:08 PM, Rob Herring <robh@kernel.org> wrote: > > On Tue, Feb 02, 2016 at 05:59:11PM +0800, Andy Yan wrote: > >> add device tree bindings document for reboot-mode driver > >> > >> Signed-off-by: Andy Yan <andy.yan@rock-chips.com> > >> > >> --- > >> > >> Changes in v3: > >> - descirbe all reboot mode as properity instead of subnode > >> > >> Changes in v2: None > >> Changes in v1: None > >> > >> .../bindings/power/reset/reboot-mode.txt | 26 ++++++++++++++++ > >> .../bindings/power/reset/syscon-reboot-mode.txt | 36 ++++++++++++++++++++++ > >> 2 files changed, 62 insertions(+) > >> create mode 100644 Documentation/devicetree/bindings/power/reset/reboot-mode.txt > >> create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt > >> > >> diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt > >> new file mode 100644 > >> index 0000000..517080f > >> --- /dev/null > >> +++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt > >> @@ -0,0 +1,26 @@ > >> +Generic reboot mode core map driver > >> + > >> +This driver get reboot mode arguments and call the write > >> +interface to stores the magic value in special register > >> +or ram . Then the bootloader can read it and take different > >> +action according the argument stored. > >> + > >> +All mode properties are vendor specific, it is a indication to tell > > > > The values should be vendor specific. The property names should not. We > > can allow vendor specific ones, but we need to have a common set. > > > >> +the bootloder what to do when the system reboot, and should be named > >> +as mode-xxx = <magic> (xxx is mode name). > >> + > >> +- mode-normal: Normal reboot mode, system reboot with command "reboot". > >> +- mode-recovery: Android Recovery mode, it is a mode to format the device or update a new image. > >> +- mode-fastboot: Android fastboot mode, it's a mode to re-flash partitions on the device. > >> +- mode-loader: A bootloader mode, it's a mode used to download image on Rockchip platform, > >> + usually used in development. > >> +- mode-maskrom: It's a mode to download bootloader on Rockchip platform. > >> + > >> +Example: > >> + reboot-mode { > >> + mode-normal = <BOOT_NORMAL>; > >> + mode-recovery = <BOOT_RECOVERY>; > >> + mode-fastboot = <BOOT_FASTBOOT>; > > > > I tend to agree with John on calling this mode-bootloader. > > > > OTOH, fastboot is more specific about what the mode is. The name in DT > > and the userspace name don't necessarily have to be the same. > > Wait. This is a bit confusing. The utility of adding a property name > and using that name be the reboot command parsed for made sense > (compared to earlier versions which had command strings) as it made > the dts more terse. But it sounds here like you're suggesting we > should have some logic in the driver that translates "reboot fastboot" > to mode-bootloader or vice versa. I said early on the DT names and kernel-userspace names should not necessarily be linked. They can be, but we shouldn't require that. My concern with mode-bootloader is what if you can boot into multiple bootloader modes. Say USB mass storage is one option. "bootloader" is not real specific. > >> + mode-loader = <BOOT_LOADER>; > > > > This one needs a better name. Maybe it should be 'rockchip,mode-loader' > > as it is vendor specific. Either way, loader is vague. Perhaps > > rockchip,mode-bl-download? > > Hrm. So how what reboot command do you expect to trigger that? Whatever your OS has defined to map to that. We could just decide the kernel will strip <vendor> and 'mode-' and match commands against what remains. > Though I do like the vendor specific prefix here, as it clarifies how > universal the command is (and its easy add standard commands if they > become more established and remap things in the future). > > > > >> + mode-maskrom = <BOOT_MASKROM>; > > > > I think this should be "mode-rom-download". > > I think one of the difficult things here is that there's no real > standards for all bios/bootloader modes. So they are somewhat > firmware/bootloader/device specific, and thus we need something that > is flexible enough to allow lots of different modes to be easily > specified. That said, this does expose a userspace interface (though > one could argue kernel ABI doesn't cross reboots :) so we should try > to have some consistency so the same userspace can work on various > devices. There is: UEFI. Boot mode efivars are standard. But then they are pretty much PC oriented though. It is more which device to boot off of, but there is network boot or boot to bios setup. > I do think the "bootloader" and "recovery" arguments are somewhat > defacto standards, well established on most android devices. Yes, otherwise I'd be completely against "mode-bootloader" as the property. > I think here the concern is rockchip probably has some userspace that > is already using "reboot maskrom" or "reboot loader" for their own > uses. And its a bit of a pain to ask that userspace to be reworked to Perhaps those are only for development and change would not be so painful. > use "reboot rom-download" or "reboot rockchip,rom-download" depending > on how we try to deal with these. (Granted, non-upstream interfaces > aren't official, so that is their risk somewhat, but we avoid being > smug about that :) Or vendor specific modes require vendor specific translation in the kernel. To some extent we need to design what is right and worry about future devices rather than cater to past devices. There's always some compromise. What would you design ignoring the existing conditions. Start there and then figure out how to make it work with current designs. > Another part of the issue is there isn't really a way to probe for > reboot cmd capability here. As much as I'd rather not complicate > things, one couldn't easily extend existing userspace to work with > current kernels as well as future kernels, since the reboot with an > invalid command won't fail. The machine still resets. So you can't try > one and fallback to the other. Well, that's nice. Maybe we should change that? Or we're stuck with that ABI? > Maybe there needs to be a sysfs entry with the list of the supported commands? You can just read the DT. Although, the problem then is what happens when we move to the next firmware interface. We see that some with devices having userspace dependencies on ATAGS. Rob
On Thu, Feb 4, 2016 at 8:35 PM, Rob Herring <robh@kernel.org> wrote: > On Thu, Feb 04, 2016 at 03:46:15PM -0800, John Stultz wrote: >> On Thu, Feb 4, 2016 at 3:08 PM, Rob Herring <robh@kernel.org> wrote: >> > On Tue, Feb 02, 2016 at 05:59:11PM +0800, Andy Yan wrote: >> >> +Example: >> >> + reboot-mode { >> >> + mode-normal = <BOOT_NORMAL>; >> >> + mode-recovery = <BOOT_RECOVERY>; >> >> + mode-fastboot = <BOOT_FASTBOOT>; >> > >> > I tend to agree with John on calling this mode-bootloader. >> > >> > OTOH, fastboot is more specific about what the mode is. The name in DT >> > and the userspace name don't necessarily have to be the same. >> >> Wait. This is a bit confusing. The utility of adding a property name >> and using that name be the reboot command parsed for made sense >> (compared to earlier versions which had command strings) as it made >> the dts more terse. But it sounds here like you're suggesting we >> should have some logic in the driver that translates "reboot fastboot" >> to mode-bootloader or vice versa. > > I said early on the DT names and kernel-userspace names should not > necessarily be linked. They can be, but we shouldn't require that. Sigh. Ok. It seemed it was due to earlier comments (maybe from others, but I thought it was you), that we moved from specifying a command string, to using the label. But if you think the label name and the commands shouldn't be linked, it seems like we should re-introduce that. No? Unless your thinking we need some sort of static in-kernel mapping of commands to label names? But that just seems painfully indirect for little gain ("Its obvious! For that mode, you use this term here, and that different term over there!"). > My concern with mode-bootloader is what if you can boot into multiple > bootloader modes. Say USB mass storage is one option. "bootloader" is > not real specific. True. But as I think we agreed below, "bootloader" and "recovery" are basically defacto standards, and I think it would be a bad idea to try to declare all the existing android tooling and docs wrong just because the command is vague, technically. >> >> + mode-loader = <BOOT_LOADER>; >> > >> > This one needs a better name. Maybe it should be 'rockchip,mode-loader' >> > as it is vendor specific. Either way, loader is vague. Perhaps >> > rockchip,mode-bl-download? >> >> Hrm. So how what reboot command do you expect to trigger that? > > Whatever your OS has defined to map to that. > > We could just decide the kernel will strip <vendor> and 'mode-' and > match commands against what remains. That part sounds sane, although I do think having vendor prefixes are reasonable for actual commands as well. >> I think one of the difficult things here is that there's no real >> standards for all bios/bootloader modes. So they are somewhat >> firmware/bootloader/device specific, and thus we need something that >> is flexible enough to allow lots of different modes to be easily >> specified. That said, this does expose a userspace interface (though >> one could argue kernel ABI doesn't cross reboots :) so we should try >> to have some consistency so the same userspace can work on various >> devices. > > There is: UEFI. Boot mode efivars are standard. But then they are pretty > much PC oriented though. It is more which device to boot off of, but > there is network boot or boot to bios setup. Well, there's a partial standard there. I'm told for android on x86, there is no UEFI standard way to communicate rebooting to fastboot or recovery. Every device does its own device specific driver. >> I do think the "bootloader" and "recovery" arguments are somewhat >> defacto standards, well established on most android devices. > > Yes, otherwise I'd be completely against "mode-bootloader" as the > property. Ok. >> I think here the concern is rockchip probably has some userspace that >> is already using "reboot maskrom" or "reboot loader" for their own >> uses. And its a bit of a pain to ask that userspace to be reworked to > > Perhaps those are only for development and change would not be so > painful. Andy: Can you comment here? How critical are the specific commands you've used here for your userspace? >> use "reboot rom-download" or "reboot rockchip,rom-download" depending >> on how we try to deal with these. (Granted, non-upstream interfaces >> aren't official, so that is their risk somewhat, but we avoid being >> smug about that :) > > Or vendor specific modes require vendor specific translation in the > kernel. True. > To some extent we need to design what is right and worry about future > devices rather than cater to past devices. There's always some > compromise. What would you design ignoring the existing conditions. > Start there and then figure out how to make it work with current > designs. Fair enough. I just want to make sure we're not getting too caught up with design purity and are willing the meet the world where it is. >> Another part of the issue is there isn't really a way to probe for >> reboot cmd capability here. As much as I'd rather not complicate >> things, one couldn't easily extend existing userspace to work with >> current kernels as well as future kernels, since the reboot with an >> invalid command won't fail. The machine still resets. So you can't try >> one and fallback to the other. > > Well, that's nice. Maybe we should change that? Or we're stuck with > that ABI? Maybe? I'm not sure what might have trouble with reboot failing if it sticks any extra noise in the reboot command. I'd probably lean towards sticking with the existing behavior. >> Maybe there needs to be a sysfs entry with the list of the supported commands? > > You can just read the DT. Although, the problem then is what happens > when we move to the next firmware interface. We see that some with > devices having userspace dependencies on ATAGS. Heh. I guess. Thought I suspect "Just read the DT to sort out the available reboot modes" is probably not what most userspace wants to hear. :) thanks -john
On Thu, Feb 04, 2016 at 09:03:44PM -0800, John Stultz wrote: > On Thu, Feb 4, 2016 at 8:35 PM, Rob Herring <robh@kernel.org> wrote: > > On Thu, Feb 04, 2016 at 03:46:15PM -0800, John Stultz wrote: > >> On Thu, Feb 4, 2016 at 3:08 PM, Rob Herring <robh@kernel.org> wrote: > >> > On Tue, Feb 02, 2016 at 05:59:11PM +0800, Andy Yan wrote: > >> >> +Example: > >> >> + reboot-mode { > >> >> + mode-normal = <BOOT_NORMAL>; > >> >> + mode-recovery = <BOOT_RECOVERY>; > >> >> + mode-fastboot = <BOOT_FASTBOOT>; > >> > > >> > I tend to agree with John on calling this mode-bootloader. > >> > > >> > OTOH, fastboot is more specific about what the mode is. The name in DT > >> > and the userspace name don't necessarily have to be the same. > >> > >> Wait. This is a bit confusing. The utility of adding a property name > >> and using that name be the reboot command parsed for made sense > >> (compared to earlier versions which had command strings) as it made > >> the dts more terse. But it sounds here like you're suggesting we > >> should have some logic in the driver that translates "reboot fastboot" > >> to mode-bootloader or vice versa. > > > > I said early on the DT names and kernel-userspace names should not > > necessarily be linked. They can be, but we shouldn't require that. > > Sigh. Ok. It seemed it was due to earlier comments (maybe from others, > but I thought it was you), that we moved from specifying a command > string, to using the label. But if you think the label name and the > commands shouldn't be linked, it seems like we should re-introduce > that. No? > > Unless your thinking we need some sort of static in-kernel mapping of > commands to label names? But that just seems painfully indirect for > little gain ("Its obvious! For that mode, you use this term here, and > that different term over there!"). Tying it to a Linux ABI makes the binding Linux specific. I don't have a problem that the strings happen to be the same, but we should have some understanding that they may not be and allow for that. > > My concern with mode-bootloader is what if you can boot into multiple > > bootloader modes. Say USB mass storage is one option. "bootloader" is > > not real specific. > > True. But as I think we agreed below, "bootloader" and "recovery" are > basically defacto standards, and I think it would be a bad idea to try > to declare all the existing android tooling and docs wrong just > because the command is vague, technically. Okay, as long as they are clearly documented what they mean. > >> >> + mode-loader = <BOOT_LOADER>; > >> > > >> > This one needs a better name. Maybe it should be 'rockchip,mode-loader' > >> > as it is vendor specific. Either way, loader is vague. Perhaps > >> > rockchip,mode-bl-download? > >> > >> Hrm. So how what reboot command do you expect to trigger that? > > > > Whatever your OS has defined to map to that. > > > > We could just decide the kernel will strip <vendor> and 'mode-' and > > match commands against what remains. > > That part sounds sane, although I do think having vendor prefixes are > reasonable for actual commands as well. Well, you could still have "rockchip,mode-rockchip-bl-download"... We can bikeshed that when get there. The other way random custom modes could be done is just allow the raw value to be passed from userspace converting the string to a number. Then we have no abstraction rather than half way abstracting it. > >> I think one of the difficult things here is that there's no real > >> standards for all bios/bootloader modes. So they are somewhat > >> firmware/bootloader/device specific, and thus we need something that > >> is flexible enough to allow lots of different modes to be easily > >> specified. That said, this does expose a userspace interface (though > >> one could argue kernel ABI doesn't cross reboots :) so we should try > >> to have some consistency so the same userspace can work on various > >> devices. > > > > There is: UEFI. Boot mode efivars are standard. But then they are pretty > > much PC oriented though. It is more which device to boot off of, but > > there is network boot or boot to bios setup. > > Well, there's a partial standard there. I'm told for android on x86, > there is no UEFI standard way to communicate rebooting to fastboot or > recovery. Every device does its own device specific driver. So much for standards. However, while these specific modes have not been standardized, there is a set of standard modes and these could have been added to the existing mechanism. So there at least exists some model to draw inspiration from. Rob
Hi Rob & John: On 2016?02?05? 13:03, John Stultz wrote: > On Thu, Feb 4, 2016 at 8:35 PM, Rob Herring <robh@kernel.org> wrote: >> On Thu, Feb 04, 2016 at 03:46:15PM -0800, John Stultz wrote: >>> On Thu, Feb 4, 2016 at 3:08 PM, Rob Herring <robh@kernel.org> wrote: >>>> On Tue, Feb 02, 2016 at 05:59:11PM +0800, Andy Yan wrote: >>>>> +Example: >>>>> + reboot-mode { >>>>> + mode-normal = <BOOT_NORMAL>; >>>>> + mode-recovery = <BOOT_RECOVERY>; >>>>> + mode-fastboot = <BOOT_FASTBOOT>; >>>> I tend to agree with John on calling this mode-bootloader. >>>> >>>> OTOH, fastboot is more specific about what the mode is. The name in DT >>>> and the userspace name don't necessarily have to be the same. >>> Wait. This is a bit confusing. The utility of adding a property name >>> and using that name be the reboot command parsed for made sense >>> (compared to earlier versions which had command strings) as it made >>> the dts more terse. But it sounds here like you're suggesting we >>> should have some logic in the driver that translates "reboot fastboot" >>> to mode-bootloader or vice versa. >> I said early on the DT names and kernel-userspace names should not >> necessarily be linked. They can be, but we shouldn't require that. > Sigh. Ok. It seemed it was due to earlier comments (maybe from others, > but I thought it was you), that we moved from specifying a command > string, to using the label. But if you think the label name and the > commands shouldn't be linked, it seems like we should re-introduce > that. No? > > Unless your thinking we need some sort of static in-kernel mapping of > commands to label names? But that just seems painfully indirect for > little gain ("Its obvious! For that mode, you use this term here, and > that different term over there!"). > >> My concern with mode-bootloader is what if you can boot into multiple >> bootloader modes. Say USB mass storage is one option. "bootloader" is >> not real specific. > True. But as I think we agreed below, "bootloader" and "recovery" are > basically defacto standards, and I think it would be a bad idea to try > to declare all the existing android tooling and docs wrong just > because the command is vague, technically. > > >>>>> + mode-loader = <BOOT_LOADER>; >>>> This one needs a better name. Maybe it should be 'rockchip,mode-loader' >>>> as it is vendor specific. Either way, loader is vague. Perhaps >>>> rockchip,mode-bl-download? >>> Hrm. So how what reboot command do you expect to trigger that? >> Whatever your OS has defined to map to that. >> >> We could just decide the kernel will strip <vendor> and 'mode-' and >> match commands against what remains. > That part sounds sane, although I do think having vendor prefixes are > reasonable for actual commands as well. > > >>> I think one of the difficult things here is that there's no real >>> standards for all bios/bootloader modes. So they are somewhat >>> firmware/bootloader/device specific, and thus we need something that >>> is flexible enough to allow lots of different modes to be easily >>> specified. That said, this does expose a userspace interface (though >>> one could argue kernel ABI doesn't cross reboots :) so we should try >>> to have some consistency so the same userspace can work on various >>> devices. >> There is: UEFI. Boot mode efivars are standard. But then they are pretty >> much PC oriented though. It is more which device to boot off of, but >> there is network boot or boot to bios setup. > Well, there's a partial standard there. I'm told for android on x86, > there is no UEFI standard way to communicate rebooting to fastboot or > recovery. Every device does its own device specific driver. > > >>> I do think the "bootloader" and "recovery" arguments are somewhat >>> defacto standards, well established on most android devices. >> Yes, otherwise I'd be completely against "mode-bootloader" as the >> property. > Ok. > >>> I think here the concern is rockchip probably has some userspace that >>> is already using "reboot maskrom" or "reboot loader" for their own >>> uses. And its a bit of a pain to ask that userspace to be reworked to >> Perhaps those are only for development and change would not be so >> painful. > Andy: Can you comment here? How critical are the specific commands > you've used here for your userspace? > Have some discussion with my colleague, we decided remove the" maskrom" mode in next version. Actually, this mode is not so used so often. But "reboot loader" is frequently used in development by all the rockchip platform related people, even some widely used factory tools use this command.So we really hope it can compatible with the existing tools and user experience. >>> use "reboot rom-download" or "reboot rockchip,rom-download" depending >>> on how we try to deal with these. (Granted, non-upstream interfaces >>> aren't official, so that is their risk somewhat, but we avoid being >>> smug about that :) >> Or vendor specific modes require vendor specific translation in the >> kernel. > True. > > >> To some extent we need to design what is right and worry about future >> devices rather than cater to past devices. There's always some >> compromise. What would you design ignoring the existing conditions. >> Start there and then figure out how to make it work with current >> designs. > Fair enough. I just want to make sure we're not getting too caught up > with design purity and are willing the meet the world where it is. > >>> Another part of the issue is there isn't really a way to probe for >>> reboot cmd capability here. As much as I'd rather not complicate >>> things, one couldn't easily extend existing userspace to work with >>> current kernels as well as future kernels, since the reboot with an >>> invalid command won't fail. The machine still resets. So you can't try >>> one and fallback to the other. >> Well, that's nice. Maybe we should change that? Or we're stuck with >> that ABI? > Maybe? I'm not sure what might have trouble with reboot failing if it > sticks any extra noise in the reboot command. > I'd probably lean towards sticking with the existing behavior. > >>> Maybe there needs to be a sysfs entry with the list of the supported commands? >> You can just read the DT. Although, the problem then is what happens >> when we move to the next firmware interface. We see that some with >> devices having userspace dependencies on ATAGS. > Heh. I guess. Thought I suspect "Just read the DT to sort out the > available reboot modes" is probably not what most userspace wants to > hear. :) > > thanks > -john > > _______________________________________________ > Linux-rockchip mailing list > Linux-rockchip@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-rockchip > > >
diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt new file mode 100644 index 0000000..517080f --- /dev/null +++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt @@ -0,0 +1,26 @@ +Generic reboot mode core map driver + +This driver get reboot mode arguments and call the write +interface to stores the magic value in special register +or ram . Then the bootloader can read it and take different +action according the argument stored. + +All mode properties are vendor specific, it is a indication to tell +the bootloder what to do when the system reboot, and should be named +as mode-xxx = <magic> (xxx is mode name). + +- mode-normal: Normal reboot mode, system reboot with command "reboot". +- mode-recovery: Android Recovery mode, it is a mode to format the device or update a new image. +- mode-fastboot: Android fastboot mode, it's a mode to re-flash partitions on the device. +- mode-loader: A bootloader mode, it's a mode used to download image on Rockchip platform, + usually used in development. +- mode-maskrom: It's a mode to download bootloader on Rockchip platform. + +Example: + reboot-mode { + mode-normal = <BOOT_NORMAL>; + mode-recovery = <BOOT_RECOVERY>; + mode-fastboot = <BOOT_FASTBOOT>; + mode-loader = <BOOT_LOADER>; + mode-maskrom = <BOOT_MASKROM>; + } diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt new file mode 100644 index 0000000..923c82b --- /dev/null +++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt @@ -0,0 +1,36 @@ +SYSCON reboot mode driver + +This driver get reboot mode magic value form reboot-mode driver +and stores it in a SYSCON mapped register. Then the bootloader +can read it and take different action according to the magic +value stored. + +This DT node should be represented as a sub-node of a "syscon", "simple-mfd" +node. + +Required properties: +- compatible: should be "syscon-reboot-mode" +- offset: offset in the register map for the storage register (in bytes) + +Optional properity: +- mask: the mask bits of the mode magic value, default set to 0xffffffff if missing. + +The rest of the properties should follow the generic reboot-mode discription +found in reboot-mode.txt + +Example: + pmu: pmu@20004000 { + compatible = "rockchip,rk3066-pmu", "syscon", "simple-mfd"; + reg = <0x20004000 0x100>; + + reboot-mode { + compatible = "syscon-reboot-mode"; + offset = <0x40>; + mode-normal = <BOOT_NORMAL>; + mode-recovery = <BOOT_RECOVERY>; + mode-fastboot = <BOOT_FASTBOOT>; + mode-loader = <BOOT_LOADER>; + mode-maskrom = <BOOT_MASKROM>; + + }; + };
add device tree bindings document for reboot-mode driver Signed-off-by: Andy Yan <andy.yan@rock-chips.com> --- Changes in v3: - descirbe all reboot mode as properity instead of subnode Changes in v2: None Changes in v1: None .../bindings/power/reset/reboot-mode.txt | 26 ++++++++++++++++ .../bindings/power/reset/syscon-reboot-mode.txt | 36 ++++++++++++++++++++++ 2 files changed, 62 insertions(+) create mode 100644 Documentation/devicetree/bindings/power/reset/reboot-mode.txt create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt