[RFC,0/4] Implement a PSCI SYSTEM_RESET2 reboot-mode driver

  PSCI implements a restart notifier for architectural defined resets.
The SYSTEM_RESET2 call allows vendor firmware to define additional reset
types which could be mapped to the reboot reason.

Implement a driver to wire the reboot-mode framework to make vendor
SYSTEM_RESET2 calls on reboot.

This is a continuation from https://lore.kernel.org/all/4a679542-b48d-7e11-f33a-63535a5c68cb@quicinc.com/

Elliot Berman (4):
  power: reset: reboot-mode: Allow magic to be 0
  power: reset: reboot-mode: Wire reboot_mode enum to magic
  dt-bindings: power: reset: Document arm,psci-vendor-reset
  power: reset: Implement a PSCI SYSTEM_RESET2 reboot-mode driver

 .../power/reset/arm,psci-vendor-reset.yaml    | 35 +++++++++++++
 MAINTAINERS                                   |  2 +
 drivers/firmware/psci/psci.c                  |  9 ++++
 drivers/power/reset/Kconfig                   |  9 ++++
 drivers/power/reset/Makefile                  |  1 +
 drivers/power/reset/psci-vendor-reset.c       | 49 +++++++++++++++++++
 drivers/power/reset/reboot-mode.c             | 44 ++++++++++++-----
 include/linux/psci.h                          |  2 +
 8 files changed, 139 insertions(+), 12 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
 create mode 100644 drivers/power/reset/psci-vendor-reset.c


base-commit: 6eaae198076080886b9e7d57f4ae06fa782f90ef
  

On Mon, Jul 24, 2023 at 03:30:53PM -0700, Elliot Berman wrote:
> Add devicetree bindings for using PSCI SYSTEM_RESET2 with vendor reset  types.
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  .../power/reset/arm,psci-vendor-reset.yaml    | 35 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 36 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> 
> diff --git a/Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml b/Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> new file mode 100644
> index 000000000000..18b0b8c167a1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> @@ -0,0 +1,35 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2023 Qualcomm Innovation Center, Inc. All Rights Reserved.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/power/reset/arm,psci-vendor-reset.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: PSCI SYSTEM_RESET2 Vendor Resets
> +
> +maintainers:
> +  - Elliot Berman <quic_eberman@quicinc.com>
> +
> +description: |
> +  PSCI SYSTEM_RESET2 supports vendor-defined reset types. This describes
> +  the conversion of reboot modes to the reset types.
> +
> +properties:
> +  compatible:
> +    const: arm,psci-vendor-reset
> +
> +allOf:
> +  - $ref: reboot-mode.yaml#
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    firmware {
> +      psci-vendor-resets {
> +        compatible = "arm,psci-vendor-reset";

We already have a node for PSCI, we don't need a second one. You can 
have a separate driver without a separate node. 

> +        reboot-normal = <0x100>;

Wouldn't 'normal' be the normal PSCI reset?

> +        reboot-bootloader = <0x101>;
> +        reboot-fastboot = <0x102>;
> +      };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d516295978a4..2da4c5f1917b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16982,6 +16982,7 @@ M:	Mark Rutland <mark.rutland@arm.com>
>  M:	Lorenzo Pieralisi <lpieralisi@kernel.org>
>  L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
>  S:	Maintained
> +F:	Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
>  F:	drivers/firmware/psci/
>  F:	include/linux/psci.h
>  F:	include/uapi/linux/psci.h
> -- 
> 2.41.0
>
  

Hello,

On 7/24/23 15:30, Elliot Berman wrote:
> PSCI implements a restart notifier for architectural defined resets.
> The SYSTEM_RESET2 call allows vendor firmware to define additional reset
> types which could be mapped to the reboot reason.
> 
> Implement a driver to wire the reboot-mode framework to make vendor
> SYSTEM_RESET2 calls on reboot.
> 
> This is a continuation from https://lore.kernel.org/all/4a679542-b48d-7e11-f33a-63535a5c68cb@quicinc.com/

Would appreciate being CC'd on a the non-RFC postings of this patch. 
FWIW, my use case is better described with this earlier submission:

https://lore.kernel.org/lkml/20220122035421.4086618-1-f.fainelli@gmail.com/T/#m74e4243c1af3a8d896e19b573b58f562fa09961d

It would be neat if I could leverage your driver in order to implement 
this custom "reboot powercycle" implementation. Towards that goal, we 
would likely need to specify the desired reboot "sub" operation 
alongside its PSCI SYSTEM_RESET2 reboot type argument?

Thanks!
  

On 7/25/2023 12:12 PM, Florian Fainelli wrote:
> Hello,
> 
> On 7/24/23 15:30, Elliot Berman wrote:
>> PSCI implements a restart notifier for architectural defined resets.
>> The SYSTEM_RESET2 call allows vendor firmware to define additional reset
>> types which could be mapped to the reboot reason.
>>
>> Implement a driver to wire the reboot-mode framework to make vendor
>> SYSTEM_RESET2 calls on reboot.
>>
>> This is a continuation from 
>> https://lore.kernel.org/all/4a679542-b48d-7e11-f33a-63535a5c68cb@quicinc.com/
> 
> Would appreciate being CC'd on a the non-RFC postings of this patch. 
> FWIW, my use case is better described with this earlier submission:
> 
> https://lore.kernel.org/lkml/20220122035421.4086618-1-f.fainelli@gmail.com/T/#m74e4243c1af3a8d896e19b573b58f562fa09961d
> 
> It would be neat if I could leverage your driver in order to implement 
> this custom "reboot powercycle" implementation. Towards that goal, we 
> would likely need to specify the desired reboot "sub" operation 
> alongside its PSCI SYSTEM_RESET2 reboot type argument?
> 
> Thanks!

I think you you want to describe the PSCI vendor reset under a warm 
reboot with command "powercycle"? In other words, my series only lets DT 
describe either reboot_mode (warm) or cmd (powercycle) but not both 
simultaneously?

Please correct me if I got it wrong! Otherwise, I can incorporate way to 
describe vendor reset type matching both reboot_mode and cmd in the DT.

- Elliot
  

On 7/25/23 13:27, Elliot Berman wrote:
> 
> 
> On 7/25/2023 12:12 PM, Florian Fainelli wrote:
>> Hello,
>>
>> On 7/24/23 15:30, Elliot Berman wrote:
>>> PSCI implements a restart notifier for architectural defined resets.
>>> The SYSTEM_RESET2 call allows vendor firmware to define additional reset
>>> types which could be mapped to the reboot reason.
>>>
>>> Implement a driver to wire the reboot-mode framework to make vendor
>>> SYSTEM_RESET2 calls on reboot.
>>>
>>> This is a continuation from 
>>> https://lore.kernel.org/all/4a679542-b48d-7e11-f33a-63535a5c68cb@quicinc.com/
>>
>> Would appreciate being CC'd on a the non-RFC postings of this patch. 
>> FWIW, my use case is better described with this earlier submission:
>>
>> https://lore.kernel.org/lkml/20220122035421.4086618-1-f.fainelli@gmail.com/T/#m74e4243c1af3a8d896e19b573b58f562fa09961d
>>
>> It would be neat if I could leverage your driver in order to implement 
>> this custom "reboot powercycle" implementation. Towards that goal, we 
>> would likely need to specify the desired reboot "sub" operation 
>> alongside its PSCI SYSTEM_RESET2 reboot type argument?
>>
>> Thanks!
> 
> I think you you want to describe the PSCI vendor reset under a warm 
> reboot with command "powercycle"? In other words, my series only lets DT 
> describe either reboot_mode (warm) or cmd (powercycle) but not both 
> simultaneously?

I did not give a lot of thoughts into the different types of reboot 
(warm, soft, cold) and just went with an extension of whichever reboot 
type we have to be supplemented by the "powercycle" command. It seems 
like we should support both the reboot type and command, it would be 
fine with me if I had to specify reboot_mode + cmd for each reboot_mode.