Current reboot-mode supports a single 32-bit argument for any
supported mode. Some reboot-mode based drivers may require
passing two independent 32-bit arguments during a reboot
sequence, for uses-cases, where a mode requires an additional
argument. Such drivers may not be able to use the reboot-mode
driver. For example, ARM PSCI vendor-specific resets, need two
arguments for its operation – reset_type and cookie, to complete
the reset operation. If a driver wants to implement this
firmware-based reset, it cannot use reboot-mode framework.

Introduce 64-bit magic values in reboot-mode driver to
accommodate dual 32-bit arguments when specified via device tree.
In cases, where no second argument is passed from device tree,
keep the upper 32-bit of magic un-changed(0) to maintain backward
compatibility.

Update the current drivers using reboot-mode for a 64-bit magic
value.

Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
---
 drivers/power/reset/nvmem-reboot-mode.c  | 13 +++++++++----
 drivers/power/reset/qcom-pon.c           | 11 ++++++++---
 drivers/power/reset/reboot-mode.c        | 19 +++++++++++++------
 drivers/power/reset/syscon-reboot-mode.c | 11 ++++++++---
 include/linux/reboot-mode.h              |  3 ++-
 5 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/drivers/power/reset/nvmem-reboot-mode.c b/drivers/power/reset/nvmem-reboot-mode.c
index 41530b70cfc48c2a83fbbd96f523d5816960a0d1..5d73dde585b1fd438b1847f884feb37cd9e4dd5c 100644
--- a/drivers/power/reset/nvmem-reboot-mode.c
+++ b/drivers/power/reset/nvmem-reboot-mode.c
@@ -16,15 +16,20 @@ struct nvmem_reboot_mode {
 	struct nvmem_cell *cell;
 };
 
-static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
-				    unsigned int magic)
+static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
 {
-	int ret;
 	struct nvmem_reboot_mode *nvmem_rbm;
+	u32 magic_32;
+	int ret;
+
+	if (magic > U32_MAX)
+		return -EINVAL;
+
+	magic_32 = magic;
 
 	nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
 
-	ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
+	ret = nvmem_cell_write(nvmem_rbm->cell, &magic_32, sizeof(magic_32));
 	if (ret < 0)
 		dev_err(reboot->dev, "update reboot mode bits failed\n");
 
diff --git a/drivers/power/reset/qcom-pon.c b/drivers/power/reset/qcom-pon.c
index 7e108982a582e8243c5c806bd4a793646b87189f..d0ed9431a02313a7bbaa93743c16fa1ae713ddfe 100644
--- a/drivers/power/reset/qcom-pon.c
+++ b/drivers/power/reset/qcom-pon.c
@@ -27,17 +27,22 @@ struct qcom_pon {
 	long reason_shift;
 };
 
-static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot,
-				    unsigned int magic)
+static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
 {
 	struct qcom_pon *pon = container_of
 			(reboot, struct qcom_pon, reboot_mode);
+	u32 magic_32;
 	int ret;
 
+	if (magic > U32_MAX || (magic << pon->reason_shift) > U32_MAX)
+		return -EINVAL;
+
+	magic_32 = magic << pon->reason_shift;
+
 	ret = regmap_update_bits(pon->regmap,
 				 pon->baseaddr + PON_SOFT_RB_SPARE,
 				 GENMASK(7, pon->reason_shift),
-				 magic << pon->reason_shift);
+				 magic_32);
 	if (ret < 0)
 		dev_err(pon->dev, "update reboot mode bits failed\n");
 
diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index 9bb97bcd33cd3d58c75c791e9b568024e810e5b0..ac81b8b0a9b7fc31f8ef21024333a050087ce90f 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c
@@ -19,12 +19,11 @@
 
 struct mode_info {
 	const char *mode;
-	u32 magic;
+	u64 magic;
 	struct list_head list;
 };
 
-static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
-					  const char *cmd)
+static u64 get_reboot_mode_magic(struct reboot_mode_driver *reboot, const char *cmd)
 {
 	const char *normal = "normal";
 	struct mode_info *info;
@@ -66,7 +65,7 @@ static int reboot_mode_notify(struct notifier_block *this,
 			      unsigned long mode, void *cmd)
 {
 	struct reboot_mode_driver *reboot;
-	unsigned int magic;
+	u64 magic;
 
 	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
 	magic = get_reboot_mode_magic(reboot, cmd);
@@ -89,6 +88,8 @@ int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *
 	struct mode_info *next;
 	struct property *prop;
 	size_t len = strlen(PREFIX);
+	u32 magic_arg1;
+	u32 magic_arg2;
 	int ret;
 
 	if (!np)
@@ -108,12 +109,18 @@ int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *
 			goto error;
 		}
 
-		if (of_property_read_u32(np, prop->name, &info->magic)) {
-			pr_err("reboot mode %s without magic number\n", info->mode);
+		if (of_property_read_u32(np, prop->name, &magic_arg1)) {
+			pr_err("reboot mode without magic number\n");
 			kfree(info);
 			continue;
 		}
 
+		if (of_property_read_u32_index(np, prop->name, 1, &magic_arg2))
+			magic_arg2 = 0;
+
+		info->magic = magic_arg2;
+		info->magic = (info->magic << 32) | magic_arg1;
+
 		info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
 		if (!info->mode) {
 			ret =  -ENOMEM;
diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c
index e0772c9f70f7a19cd8ec8a0b7fdbbaa7ba44afd0..3cbd000c512239b12ec51987e900d260540a9dea 100644
--- a/drivers/power/reset/syscon-reboot-mode.c
+++ b/drivers/power/reset/syscon-reboot-mode.c
@@ -20,16 +20,21 @@ struct syscon_reboot_mode {
 	u32 mask;
 };
 
-static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
-				    unsigned int magic)
+static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
 {
 	struct syscon_reboot_mode *syscon_rbm;
+	u32 magic_32;
 	int ret;
 
+	if (magic > U32_MAX)
+		return -EINVAL;
+
+	magic_32 = magic;
+
 	syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot);
 
 	ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset,
-				 syscon_rbm->mask, magic);
+				 syscon_rbm->mask, magic_32);
 	if (ret < 0)
 		dev_err(reboot->dev, "update reboot mode bits failed\n");
 
diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
index 98f68f95c9e8460be23282c51ef7fcbed73887bd..370228b5161963aac1d75af752ada0e8282b1078 100644
--- a/include/linux/reboot-mode.h
+++ b/include/linux/reboot-mode.h
@@ -3,11 +3,12 @@
 #define __REBOOT_MODE_H__
 
 #include <linux/mutex.h>
+#include <linux/types.h>
 
 struct reboot_mode_driver {
 	struct device *dev;
 	struct list_head head;
-	int (*write)(struct reboot_mode_driver *reboot, unsigned int magic);
+	int (*write)(struct reboot_mode_driver *reboot, u64 magic);
 	struct notifier_block reboot_notifier;
 	/*Protects access to reboot mode list*/
 	struct mutex rb_lock;

-- 
2.34.1

Hi Shivendra,

On 15/08/2025 16:35, Shivendra Pratap wrote:
> Current reboot-mode supports a single 32-bit argument for any
> supported mode. Some reboot-mode based drivers may require
> passing two independent 32-bit arguments during a reboot
> sequence, for uses-cases, where a mode requires an additional
> argument. Such drivers may not be able to use the reboot-mode
> driver. For example, ARM PSCI vendor-specific resets, need two
> arguments for its operation – reset_type and cookie, to complete
> the reset operation. If a driver wants to implement this
> firmware-based reset, it cannot use reboot-mode framework.
> 
> Introduce 64-bit magic values in reboot-mode driver to
> accommodate dual 32-bit arguments when specified via device tree.
> In cases, where no second argument is passed from device tree,
> keep the upper 32-bit of magic un-changed(0) to maintain backward
> compatibility.

How about adding a n_magic_args property to struct reboot_mode_driver?
Then in struct mode_info change magic to be a u32 array of a fixed
length (currently two in-keeping with the DT bindings).

Parsing the DT values then gets simpler (u32_array) and the magic value
can be passed into the ->write() cb as a pointer since all the
reboot_mode drivers already know how big the array is. Unpopulated DT
values would just be 0.

Kind regards,

> 
> Update the current drivers using reboot-mode for a 64-bit magic
> value.
> 
> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
> ---
>  drivers/power/reset/nvmem-reboot-mode.c  | 13 +++++++++----
>  drivers/power/reset/qcom-pon.c           | 11 ++++++++---
>  drivers/power/reset/reboot-mode.c        | 19 +++++++++++++------
>  drivers/power/reset/syscon-reboot-mode.c | 11 ++++++++---
>  include/linux/reboot-mode.h              |  3 ++-
>  5 files changed, 40 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/power/reset/nvmem-reboot-mode.c b/drivers/power/reset/nvmem-reboot-mode.c
> index 41530b70cfc48c2a83fbbd96f523d5816960a0d1..5d73dde585b1fd438b1847f884feb37cd9e4dd5c 100644
> --- a/drivers/power/reset/nvmem-reboot-mode.c
> +++ b/drivers/power/reset/nvmem-reboot-mode.c
> @@ -16,15 +16,20 @@ struct nvmem_reboot_mode {
>  	struct nvmem_cell *cell;
>  };
>  
> -static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
> -				    unsigned int magic)
> +static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
>  {
> -	int ret;
>  	struct nvmem_reboot_mode *nvmem_rbm;
> +	u32 magic_32;
> +	int ret;
> +
> +	if (magic > U32_MAX)
> +		return -EINVAL;
> +
> +	magic_32 = magic;
>  
>  	nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
>  
> -	ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
> +	ret = nvmem_cell_write(nvmem_rbm->cell, &magic_32, sizeof(magic_32));
>  	if (ret < 0)
>  		dev_err(reboot->dev, "update reboot mode bits failed\n");
>  
> diff --git a/drivers/power/reset/qcom-pon.c b/drivers/power/reset/qcom-pon.c
> index 7e108982a582e8243c5c806bd4a793646b87189f..d0ed9431a02313a7bbaa93743c16fa1ae713ddfe 100644
> --- a/drivers/power/reset/qcom-pon.c
> +++ b/drivers/power/reset/qcom-pon.c
> @@ -27,17 +27,22 @@ struct qcom_pon {
>  	long reason_shift;
>  };
>  
> -static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot,
> -				    unsigned int magic)
> +static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
>  {
>  	struct qcom_pon *pon = container_of
>  			(reboot, struct qcom_pon, reboot_mode);
> +	u32 magic_32;
>  	int ret;
>  
> +	if (magic > U32_MAX || (magic << pon->reason_shift) > U32_MAX)
> +		return -EINVAL;
> +
> +	magic_32 = magic << pon->reason_shift;
> +
>  	ret = regmap_update_bits(pon->regmap,
>  				 pon->baseaddr + PON_SOFT_RB_SPARE,
>  				 GENMASK(7, pon->reason_shift),
> -				 magic << pon->reason_shift);
> +				 magic_32);
>  	if (ret < 0)
>  		dev_err(pon->dev, "update reboot mode bits failed\n");
>  
> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> index 9bb97bcd33cd3d58c75c791e9b568024e810e5b0..ac81b8b0a9b7fc31f8ef21024333a050087ce90f 100644
> --- a/drivers/power/reset/reboot-mode.c
> +++ b/drivers/power/reset/reboot-mode.c
> @@ -19,12 +19,11 @@
>  
>  struct mode_info {
>  	const char *mode;
> -	u32 magic;
> +	u64 magic;
>  	struct list_head list;
>  };
>  
> -static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
> -					  const char *cmd)
> +static u64 get_reboot_mode_magic(struct reboot_mode_driver *reboot, const char *cmd)
>  {
>  	const char *normal = "normal";
>  	struct mode_info *info;
> @@ -66,7 +65,7 @@ static int reboot_mode_notify(struct notifier_block *this,
>  			      unsigned long mode, void *cmd)
>  {
>  	struct reboot_mode_driver *reboot;
> -	unsigned int magic;
> +	u64 magic;
>  
>  	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
>  	magic = get_reboot_mode_magic(reboot, cmd);
> @@ -89,6 +88,8 @@ int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *
>  	struct mode_info *next;
>  	struct property *prop;
>  	size_t len = strlen(PREFIX);
> +	u32 magic_arg1;
> +	u32 magic_arg2;
>  	int ret;
>  
>  	if (!np)
> @@ -108,12 +109,18 @@ int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *
>  			goto error;
>  		}
>  
> -		if (of_property_read_u32(np, prop->name, &info->magic)) {
> -			pr_err("reboot mode %s without magic number\n", info->mode);
> +		if (of_property_read_u32(np, prop->name, &magic_arg1)) {
> +			pr_err("reboot mode without magic number\n");
>  			kfree(info);
>  			continue;
>  		}
>  
> +		if (of_property_read_u32_index(np, prop->name, 1, &magic_arg2))
> +			magic_arg2 = 0;
> +
> +		info->magic = magic_arg2;
> +		info->magic = (info->magic << 32) | magic_arg1;
> +
>  		info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
>  		if (!info->mode) {
>  			ret =  -ENOMEM;
> diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c
> index e0772c9f70f7a19cd8ec8a0b7fdbbaa7ba44afd0..3cbd000c512239b12ec51987e900d260540a9dea 100644
> --- a/drivers/power/reset/syscon-reboot-mode.c
> +++ b/drivers/power/reset/syscon-reboot-mode.c
> @@ -20,16 +20,21 @@ struct syscon_reboot_mode {
>  	u32 mask;
>  };
>  
> -static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
> -				    unsigned int magic)
> +static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
>  {
>  	struct syscon_reboot_mode *syscon_rbm;
> +	u32 magic_32;
>  	int ret;
>  
> +	if (magic > U32_MAX)
> +		return -EINVAL;
> +
> +	magic_32 = magic;
> +
>  	syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot);
>  
>  	ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset,
> -				 syscon_rbm->mask, magic);
> +				 syscon_rbm->mask, magic_32);
>  	if (ret < 0)
>  		dev_err(reboot->dev, "update reboot mode bits failed\n");
>  
> diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
> index 98f68f95c9e8460be23282c51ef7fcbed73887bd..370228b5161963aac1d75af752ada0e8282b1078 100644
> --- a/include/linux/reboot-mode.h
> +++ b/include/linux/reboot-mode.h
> @@ -3,11 +3,12 @@
>  #define __REBOOT_MODE_H__
>  
>  #include <linux/mutex.h>
> +#include <linux/types.h>
>  
>  struct reboot_mode_driver {
>  	struct device *dev;
>  	struct list_head head;
> -	int (*write)(struct reboot_mode_driver *reboot, unsigned int magic);
> +	int (*write)(struct reboot_mode_driver *reboot, u64 magic);
>  	struct notifier_block reboot_notifier;
>  	/*Protects access to reboot mode list*/
>  	struct mutex rb_lock;
> 

-- 
// Casey (she/her)

On 8/28/2025 6:52 PM, Casey Connolly wrote:
> Hi Shivendra,
> 
> On 15/08/2025 16:35, Shivendra Pratap wrote:
>> Current reboot-mode supports a single 32-bit argument for any
>> supported mode. Some reboot-mode based drivers may require
>> passing two independent 32-bit arguments during a reboot
>> sequence, for uses-cases, where a mode requires an additional
>> argument. Such drivers may not be able to use the reboot-mode
>> driver. For example, ARM PSCI vendor-specific resets, need two
>> arguments for its operation – reset_type and cookie, to complete
>> the reset operation. If a driver wants to implement this
>> firmware-based reset, it cannot use reboot-mode framework.
>>
>> Introduce 64-bit magic values in reboot-mode driver to
>> accommodate dual 32-bit arguments when specified via device tree.
>> In cases, where no second argument is passed from device tree,
>> keep the upper 32-bit of magic un-changed(0) to maintain backward
>> compatibility.
> 
> How about adding a n_magic_args property to struct reboot_mode_driver?
> Then in struct mode_info change magic to be a u32 array of a fixed
> length (currently two in-keeping with the DT bindings).

Arnd/Rob,

As per previous discussion on patch v10, magic and cookie were implemented
as a 64 bit number (64 bit magic).

Need you thoughts that if we should change the magic to 32bit array, as being
suggested in the above comments.

thanks,
Shivendra

On 8/28/2025 6:52 PM, Casey Connolly wrote:
> Hi Shivendra,
> 
> On 15/08/2025 16:35, Shivendra Pratap wrote:
>> Current reboot-mode supports a single 32-bit argument for any
>> supported mode. Some reboot-mode based drivers may require
>> passing two independent 32-bit arguments during a reboot
>> sequence, for uses-cases, where a mode requires an additional
>> argument. Such drivers may not be able to use the reboot-mode
>> driver. For example, ARM PSCI vendor-specific resets, need two
>> arguments for its operation – reset_type and cookie, to complete
>> the reset operation. If a driver wants to implement this
>> firmware-based reset, it cannot use reboot-mode framework.
>>
>> Introduce 64-bit magic values in reboot-mode driver to
>> accommodate dual 32-bit arguments when specified via device tree.
>> In cases, where no second argument is passed from device tree,
>> keep the upper 32-bit of magic un-changed(0) to maintain backward
>> compatibility.
> 
> How about adding a n_magic_args property to struct reboot_mode_driver?
> Then in struct mode_info change magic to be a u32 array of a fixed
> length (currently two in-keeping with the DT bindings).
> 
> Parsing the DT values then gets simpler (u32_array) and the magic value
> can be passed into the ->write() cb as a pointer since all the
> reboot_mode drivers already know how big the array is. Unpopulated DT
> values would just be 0.


sure. Will convert it to u32 magic[2] and ->write can now pass
"u32*" and can be de-referenced by the using driver.

Could not understand that how we want to use n_magic_args and who shall
set it? Do we statically define it to two for now? or should we skip
n_magic_args for now?

thanks,
Shivendra