Re: [PATCH v20 03/10] power: reset: reboot-mode: Add support for predefined reboot modes

[Sebastian Reichel <sebastian.reichel@collabora.com>]

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Hi,

On Wed, Mar 04, 2026 at 11:33:03PM +0530, Shivendra Pratap wrote:
> reboot-mode based drivers can define a reboot-mode by adding it under
> the reboot-mode node in device tree. This limits such drivers, to define
> any predefined reboot-modes statically within the driver and creates a
> dependency on device-tree.
> 
> Introduce a list for predefined modes in the reboot-mode framework and
> process the predefined reboot-modes along with the device-tree defined
> reboot-modes. Modify existing reboot-mode based drivers to initialize
> the predefined list-head as empty.
> 
> This patch enables a reboot mode driver to define reboot-modes through a
> predefined static list, in addition to the device-tree based reboot-modes.
> 
> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
> ---

Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>

-- Sebastian

>  drivers/power/reset/nvmem-reboot-mode.c  |  1 +
>  drivers/power/reset/qcom-pon.c           |  1 +
>  drivers/power/reset/reboot-mode.c        | 28 ++++++++++++++++++++++------
>  drivers/power/reset/syscon-reboot-mode.c |  1 +
>  include/linux/reboot-mode.h              |  9 +++++++++
>  5 files changed, 34 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/power/reset/nvmem-reboot-mode.c b/drivers/power/reset/nvmem-reboot-mode.c
> index bd05d660490c686b43134f82f1eadd7665403d20..83a8d80fd7d1ccb1b736aee5f2d675246a63b8f8 100644
> --- a/drivers/power/reset/nvmem-reboot-mode.c
> +++ b/drivers/power/reset/nvmem-reboot-mode.c
> @@ -53,6 +53,7 @@ static int nvmem_reboot_mode_probe(struct platform_device *pdev)
>  
>  	nvmem_rbm->reboot.dev = &pdev->dev;
>  	nvmem_rbm->reboot.write = nvmem_reboot_mode_write;
> +	INIT_LIST_HEAD(&nvmem_rbm->reboot.predefined_modes);
>  
>  	nvmem_rbm->cell = devm_nvmem_cell_get(&pdev->dev, "reboot-mode");
>  	if (IS_ERR(nvmem_rbm->cell)) {
> diff --git a/drivers/power/reset/qcom-pon.c b/drivers/power/reset/qcom-pon.c
> index 57b36e6186f80aff947fd7f5aae5ce280c65dc6b..9d0e3fc621a6173438c6da4cce38394199451881 100644
> --- a/drivers/power/reset/qcom-pon.c
> +++ b/drivers/power/reset/qcom-pon.c
> @@ -73,6 +73,7 @@ static int qcom_pon_probe(struct platform_device *pdev)
>  		pon->reboot_mode.dev = &pdev->dev;
>  		pon->reason_shift = reason_shift;
>  		pon->reboot_mode.write = qcom_pon_reboot_mode_write;
> +		INIT_LIST_HEAD(&pon->reboot_mode.predefined_modes);
>  		error = devm_reboot_mode_register(&pdev->dev, &pon->reboot_mode);
>  		if (error) {
>  			dev_err(&pdev->dev, "can't register reboot mode\n");
> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> index f5ab6eab210bcd9670441a4d2a301d9efdf2f322..a0cd463cad42cc08c55a9d1cc11174b513995104 100644
> --- a/drivers/power/reset/reboot-mode.c
> +++ b/drivers/power/reset/reboot-mode.c
> @@ -17,12 +17,6 @@
>  
>  #define PREFIX "mode-"
>  
> -struct mode_info {
> -	const char *mode;
> -	u64 magic;
> -	struct list_head list;
> -};
> -
>  static u64 get_reboot_mode_magic(struct reboot_mode_driver *reboot, const char *cmd)
>  {
>  	const char *normal = "normal";
> @@ -73,6 +67,7 @@ static int reboot_mode_notify(struct notifier_block *this,
>   */
>  int reboot_mode_register(struct reboot_mode_driver *reboot)
>  {
> +	struct mode_info *info_predef;
>  	struct mode_info *info;
>  	struct property *prop;
>  	struct device_node *np = reboot->dev->of_node;
> @@ -82,6 +77,9 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  
>  	INIT_LIST_HEAD(&reboot->head);
>  
> +	if (!np)
> +		goto predefined_modes;
> +
>  	for_each_property_of_node(np, prop) {
>  		if (strncmp(prop->name, PREFIX, len))
>  			continue;
> @@ -115,6 +113,24 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  		list_add_tail(&info->list, &reboot->head);
>  	}
>  
> +predefined_modes:
> +	list_for_each_entry(info_predef, &reboot->predefined_modes, list) {
> +		info = kzalloc_obj(*info, GFP_KERNEL);
> +		if (!info) {
> +			ret = -ENOMEM;
> +			goto error;
> +		}
> +
> +		info->mode = kstrdup_const(info_predef->mode, GFP_KERNEL);
> +		if (!info->mode) {
> +			ret = -ENOMEM;
> +			goto error;
> +		}
> +
> +		info->magic = info_predef->magic;
> +		list_add_tail(&info->list, &reboot->head);
> +	}
> +
>  	reboot->reboot_notifier.notifier_call = reboot_mode_notify;
>  	register_reboot_notifier(&reboot->reboot_notifier);
>  
> diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c
> index 9f4b18c5e46f6a8bf197773ceceb80b250f57541..0218b71541a0cefe1534e306f956ae51ea9ee870 100644
> --- a/drivers/power/reset/syscon-reboot-mode.c
> +++ b/drivers/power/reset/syscon-reboot-mode.c
> @@ -48,6 +48,7 @@ static int syscon_reboot_mode_probe(struct platform_device *pdev)
>  	syscon_rbm->reboot.dev = &pdev->dev;
>  	syscon_rbm->reboot.write = syscon_reboot_mode_write;
>  	syscon_rbm->mask = 0xffffffff;
> +	INIT_LIST_HEAD(&syscon_rbm->reboot.predefined_modes);
>  
>  	syscon_rbm->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
>  	if (IS_ERR(syscon_rbm->map))
> diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
> index 2ce189fdfff4b396d7cc6f175b30016781ae4fe9..f07696f9439063a04fc180e953114ea09475805c 100644
> --- a/include/linux/reboot-mode.h
> +++ b/include/linux/reboot-mode.h
> @@ -4,6 +4,7 @@
>  
>  #include <linux/bitfield.h>
>  #include <linux/bits.h>
> +#include <linux/reboot.h>
>  #include <linux/types.h>
>  
>  /* Construct 64-bit reboot magic: arg2 in upper 32 bits, arg1 in lower 32 */
> @@ -15,9 +16,17 @@
>  /* Get 32 bit arg2 from 64 bit magic */
>  #define REBOOT_MODE_ARG2(magic) FIELD_GET(GENMASK_ULL(63, 32), magic)
>  
> +struct mode_info {
> +	const char *mode;
> +	u64 magic;
> +	struct list_head list;
> +};
> +
>  struct reboot_mode_driver {
>  	struct device *dev;
>  	struct list_head head;
> +	/* List of predefined reboot-modes, a reboot-mode-driver may populate. */
> +	struct list_head predefined_modes;
>  	int (*write)(struct reboot_mode_driver *reboot, u64 magic);
>  	struct notifier_block reboot_notifier;
>  };
> 
> -- 
> 2.34.1
> 

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