Re: [PATCH v1 0/6] misc: add reboot mode driver

Alexandre Belloni
2015-12-22T16:47:42Z

Hi,

On 22/12/2015 at 17:02:29 +0800, Andy Yan wrote :
>
> This driver parse the reboot commands like "reboot loader"
> and "reboot recovery" to get a boot mode described in the
> device tree , then call the vendor specific write interfae
> to store the boot mode in some place like special register
> or sram , which can be read by the bootloader after system
> reboot.
>
> This is commonly done on Android based devices, in order to
> reboot the device into fastboot or recovery mode.
>
> Before this patch , I have try some hack on[0], and then found
> John Stultz also doing the same work[1].
>
> As John is busy these days, I go on with this work.
>
> [0]https://patchwork.kernel.org/patch/7647751/
> [1]https://patchwork.kernel.org/patch/7802391/
>
> Changes in v1:
> - fix the embarrassed compile warning
> - correct the maskrom magic number
> - check for the normal reboot
> - correct the maskrom magic number
> - use macro defined in rockchip_boot-mode.h for reboot-mode DT node
>
> Andy Yan (6):
> dt-bindings: misc: add document for reboot-mode driver
> dt-bindings: soc: add document for rockchip reboot-mode driver
> misc: add reboot mode driver
> soc: rockchip: add reboot mode driver
> ARM: dts: rockchip: add reboot-mode node
> ARM64: dts: rockchip: add reboot-mode node
>

This seems nice and useful, some further ideas:

> .../devicetree/bindings/misc/reboot-mode.txt | 41 +++++++++
> .../bindings/soc/rockchip/rockchip,reboot-mode.txt | 39 +++++++++
> arch/arm/boot/dts/rk3288.dtsi | 26 ++++++
> arch/arm/boot/dts/rk3xxx.dtsi | 26 ++++++
> arch/arm64/boot/dts/rockchip/rk3368.dtsi | 26 ++++++
> drivers/misc/Kconfig | 7 ++
> drivers/misc/Makefile | 1 +
> drivers/misc/reboot_mode.c | 96 ++++++++++++++++++++++

I think this actually belongs to drivers/power/reset/ instead of misc

> drivers/soc/rockchip/Kconfig | 9 ++
> drivers/soc/rockchip/Makefile | 1 +
> drivers/soc/rockchip/reboot.c | 68 +++++++++++++++

And maybe that part could be made generic instead of rockchip specific.
It simply uses a regmap to do the accesses, I guess a lot of other
platforms will do that. We have syscon-reboot and syscon-poweroff for example.

I think then we can extend the "framework" by having generic drivers to
store the value in eeprom or nvram for example.

--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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