The reboot-mode driver does not have a strict requirement for
device-based registration. It primarily uses the device's of_node
to read mode-<cmd> properties and the device pointer for logging.
Remove the dependency on struct device and introduce support for
Device Tree (DT) node-based registration. This enables drivers
that are not associated with a struct device to leverage the
reboot-mode framework.
Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
---
drivers/power/reset/reboot-mode.c | 29 +++++++++++++++++++----------
include/linux/reboot-mode.h | 2 +-
2 files changed, 20 insertions(+), 11 deletions(-)
diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index fba53f638da04655e756b5f8b7d2d666d1379535..0269ec55106472cf2f2b12bd65704dd0114bf4a3 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c
@@ -3,13 +3,17 @@
* Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
*/
+#define pr_fmt(fmt) "reboot-mode: " fmt
+
#include <linux/device.h>
#include <linux/init.h>
#include <linux/kernel.h>
+#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/reboot.h>
#include <linux/reboot-mode.h>
+#include <linux/slab.h>
#define PREFIX "mode-"
@@ -65,33 +69,35 @@ static int reboot_mode_notify(struct notifier_block *this,
/**
* reboot_mode_register - register a reboot mode driver
* @reboot: reboot mode driver
+ * @np: Pointer to device tree node
*
* Returns: 0 on success or a negative error code on failure.
*/
-int reboot_mode_register(struct reboot_mode_driver *reboot)
+int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np)
{
struct mode_info *info;
struct property *prop;
- struct device_node *np = reboot->dev->of_node;
size_t len = strlen(PREFIX);
int ret;
+ if (!np)
+ return -EINVAL;
+
INIT_LIST_HEAD(&reboot->head);
for_each_property_of_node(np, prop) {
if (strncmp(prop->name, PREFIX, len))
continue;
- info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ret = -ENOMEM;
goto error;
}
if (of_property_read_u32(np, prop->name, &info->magic)) {
- dev_err(reboot->dev, "reboot mode %s without magic number\n",
- info->mode);
- devm_kfree(reboot->dev, info);
+ pr_err("reboot mode %s without magic number\n", info->mode);
+ kfree(info);
continue;
}
@@ -102,8 +108,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
} else if (info->mode[0] == '\0') {
kfree_const(info->mode);
ret = -EINVAL;
- dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
- prop->name);
+ pr_err("invalid mode name(%s): too short!\n", prop->name);
goto error;
}
@@ -130,11 +135,15 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
int reboot_mode_unregister(struct reboot_mode_driver *reboot)
{
struct mode_info *info;
+ struct mode_info *next;
unregister_reboot_notifier(&reboot->reboot_notifier);
- list_for_each_entry(info, &reboot->head, list)
+ list_for_each_entry_safe(info, next, &reboot->head, list) {
kfree_const(info->mode);
+ list_del(&info->list);
+ kfree(info);
+ }
return 0;
}
@@ -162,7 +171,7 @@ int devm_reboot_mode_register(struct device *dev,
if (!dr)
return -ENOMEM;
- rc = reboot_mode_register(reboot);
+ rc = reboot_mode_register(reboot, reboot->dev->of_node);
if (rc) {
devres_free(dr);
return rc;
diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
index 4a2abb38d1d612ec0fdf05eb18c98b210f631b7f..36f071f4b82e1fc255d8dd679a18e537655c3179 100644
--- a/include/linux/reboot-mode.h
+++ b/include/linux/reboot-mode.h
@@ -9,7 +9,7 @@ struct reboot_mode_driver {
struct notifier_block reboot_notifier;
};
-int reboot_mode_register(struct reboot_mode_driver *reboot);
+int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np);
int reboot_mode_unregister(struct reboot_mode_driver *reboot);
int devm_reboot_mode_register(struct device *dev,
struct reboot_mode_driver *reboot);
--
2.34.1On Thu, Jul 17, 2025 at 06:16:47PM +0530, Shivendra Pratap wrote:
> The reboot-mode driver does not have a strict requirement for
> device-based registration. It primarily uses the device's of_node
> to read mode-<cmd> properties and the device pointer for logging.
>
> Remove the dependency on struct device and introduce support for
> Device Tree (DT) node-based registration. This enables drivers
> that are not associated with a struct device to leverage the
> reboot-mode framework.
>
> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
> ---
> drivers/power/reset/reboot-mode.c | 29 +++++++++++++++++++----------
> include/linux/reboot-mode.h | 2 +-
> 2 files changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> index fba53f638da04655e756b5f8b7d2d666d1379535..0269ec55106472cf2f2b12bd65704dd0114bf4a3 100644
> --- a/drivers/power/reset/reboot-mode.c
> +++ b/drivers/power/reset/reboot-mode.c
> @@ -3,13 +3,17 @@
> * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> */
>
> +#define pr_fmt(fmt) "reboot-mode: " fmt
> +
> #include <linux/device.h>
> #include <linux/init.h>
> #include <linux/kernel.h>
> +#include <linux/list.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/reboot.h>
> #include <linux/reboot-mode.h>
> +#include <linux/slab.h>
>
> #define PREFIX "mode-"
>
> @@ -65,33 +69,35 @@ static int reboot_mode_notify(struct notifier_block *this,
> /**
> * reboot_mode_register - register a reboot mode driver
> * @reboot: reboot mode driver
> + * @np: Pointer to device tree node
> *
> * Returns: 0 on success or a negative error code on failure.
> */
> -int reboot_mode_register(struct reboot_mode_driver *reboot)
> +int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np)
> {
> struct mode_info *info;
> struct property *prop;
> - struct device_node *np = reboot->dev->of_node;
> size_t len = strlen(PREFIX);
> int ret;
>
> + if (!np)
> + return -EINVAL;
> +
> INIT_LIST_HEAD(&reboot->head);
>
> for_each_property_of_node(np, prop) {
> if (strncmp(prop->name, PREFIX, len))
> continue;
>
> - info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
> + info = kzalloc(sizeof(*info), GFP_KERNEL);
> if (!info) {
> ret = -ENOMEM;
> goto error;
> }
>
> if (of_property_read_u32(np, prop->name, &info->magic)) {
> - dev_err(reboot->dev, "reboot mode %s without magic number\n",
> - info->mode);
> - devm_kfree(reboot->dev, info);
> + pr_err("reboot mode %s without magic number\n", info->mode);
> + kfree(info);
> continue;
> }
>
> @@ -102,8 +108,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
> } else if (info->mode[0] == '\0') {
> kfree_const(info->mode);
> ret = -EINVAL;
> - dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
> - prop->name);
> + pr_err("invalid mode name(%s): too short!\n", prop->name);
> goto error;
> }
>
> @@ -130,11 +135,15 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
> int reboot_mode_unregister(struct reboot_mode_driver *reboot)
> {
> struct mode_info *info;
> + struct mode_info *next;
>
> unregister_reboot_notifier(&reboot->reboot_notifier);
>
> - list_for_each_entry(info, &reboot->head, list)
> + list_for_each_entry_safe(info, next, &reboot->head, list) {
This feels liks a missing lock.
> kfree_const(info->mode);
> + list_del(&info->list);
list_del should come before kfree, otherwise it's possible to access
freed memory while traversing the list.
> + kfree(info);
> + }
>
> return 0;
> }
> @@ -162,7 +171,7 @@ int devm_reboot_mode_register(struct device *dev,
> if (!dr)
> return -ENOMEM;
>
> - rc = reboot_mode_register(reboot);
> + rc = reboot_mode_register(reboot, reboot->dev->of_node);
> if (rc) {
> devres_free(dr);
> return rc;
> diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
> index 4a2abb38d1d612ec0fdf05eb18c98b210f631b7f..36f071f4b82e1fc255d8dd679a18e537655c3179 100644
> --- a/include/linux/reboot-mode.h
> +++ b/include/linux/reboot-mode.h
> @@ -9,7 +9,7 @@ struct reboot_mode_driver {
> struct notifier_block reboot_notifier;
> };
>
> -int reboot_mode_register(struct reboot_mode_driver *reboot);
> +int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np);
> int reboot_mode_unregister(struct reboot_mode_driver *reboot);
> int devm_reboot_mode_register(struct device *dev,
> struct reboot_mode_driver *reboot);
>
> --
> 2.34.1
>
--
With best wishes
Dmitry
On 7/19/2025 12:07 AM, Dmitry Baryshkov wrote:
> On Thu, Jul 17, 2025 at 06:16:47PM +0530, Shivendra Pratap wrote:
>> The reboot-mode driver does not have a strict requirement for
>> device-based registration. It primarily uses the device's of_node
>> to read mode-<cmd> properties and the device pointer for logging.
>>
>> Remove the dependency on struct device and introduce support for
>> Device Tree (DT) node-based registration. This enables drivers
>> that are not associated with a struct device to leverage the
>> reboot-mode framework.
>>
>> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
>> ---
>> drivers/power/reset/reboot-mode.c | 29 +++++++++++++++++++----------
>> include/linux/reboot-mode.h | 2 +-
>> 2 files changed, 20 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
>> index fba53f638da04655e756b5f8b7d2d666d1379535..0269ec55106472cf2f2b12bd65704dd0114bf4a3 100644
>> --- a/drivers/power/reset/reboot-mode.c
>> +++ b/drivers/power/reset/reboot-mode.c
>> @@ -3,13 +3,17 @@
>> * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>> */
>>
>> +#define pr_fmt(fmt) "reboot-mode: " fmt
>> +
>> #include <linux/device.h>
>> #include <linux/init.h>
>> #include <linux/kernel.h>
>> +#include <linux/list.h>
>> #include <linux/module.h>
>> #include <linux/of.h>
>> #include <linux/reboot.h>
>> #include <linux/reboot-mode.h>
>> +#include <linux/slab.h>
>>
>> #define PREFIX "mode-"
>>
>> @@ -65,33 +69,35 @@ static int reboot_mode_notify(struct notifier_block *this,
>> /**
>> * reboot_mode_register - register a reboot mode driver
>> * @reboot: reboot mode driver
>> + * @np: Pointer to device tree node
>> *
>> * Returns: 0 on success or a negative error code on failure.
>> */
>> -int reboot_mode_register(struct reboot_mode_driver *reboot)
>> +int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np)
>> {
>> struct mode_info *info;
>> struct property *prop;
>> - struct device_node *np = reboot->dev->of_node;
>> size_t len = strlen(PREFIX);
>> int ret;
>>
>> + if (!np)
>> + return -EINVAL;
>> +
>> INIT_LIST_HEAD(&reboot->head);
>>
>> for_each_property_of_node(np, prop) {
>> if (strncmp(prop->name, PREFIX, len))
>> continue;
>>
>> - info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
>> + info = kzalloc(sizeof(*info), GFP_KERNEL);
>> if (!info) {
>> ret = -ENOMEM;
>> goto error;
>> }
>>
>> if (of_property_read_u32(np, prop->name, &info->magic)) {
>> - dev_err(reboot->dev, "reboot mode %s without magic number\n",
>> - info->mode);
>> - devm_kfree(reboot->dev, info);
>> + pr_err("reboot mode %s without magic number\n", info->mode);
>> + kfree(info);
>> continue;
>> }
>>
>> @@ -102,8 +108,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>> } else if (info->mode[0] == '\0') {
>> kfree_const(info->mode);
>> ret = -EINVAL;
>> - dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
>> - prop->name);
>> + pr_err("invalid mode name(%s): too short!\n", prop->name);
>> goto error;
>> }
>>
>> @@ -130,11 +135,15 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
>> int reboot_mode_unregister(struct reboot_mode_driver *reboot)
>> {
>> struct mode_info *info;
>> + struct mode_info *next;
>>
>> unregister_reboot_notifier(&reboot->reboot_notifier);
>>
>> - list_for_each_entry(info, &reboot->head, list)
>> + list_for_each_entry_safe(info, next, &reboot->head, list) {
>
> This feels liks a missing lock.
Should we add a lock here? The list will mostly be fully created only
once at the time of registration.
- thanks.
>
>> kfree_const(info->mode);
>> + list_del(&info->list);
>
> list_del should come before kfree, otherwise it's possible to access
> freed memory while traversing the list.
sure. will make it list_del(&info->list) and then kfree_const(info->mode).
- thanks.
>
>> + kfree(info);
>> + }
>>
>> return 0;
>> }
>> @@ -162,7 +171,7 @@ int devm_reboot_mode_register(struct device *dev,
>> if (!dr)
>> return -ENOMEM;
>>
>> - rc = reboot_mode_register(reboot);
>> + rc = reboot_mode_register(reboot, reboot->dev->of_node);
>> if (rc) {
>> devres_free(dr);
>> return rc;
>> diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
>> index 4a2abb38d1d612ec0fdf05eb18c98b210f631b7f..36f071f4b82e1fc255d8dd679a18e537655c3179 100644
>> --- a/include/linux/reboot-mode.h
>> +++ b/include/linux/reboot-mode.h
>> @@ -9,7 +9,7 @@ struct reboot_mode_driver {
>> struct notifier_block reboot_notifier;
>> };
>>
>> -int reboot_mode_register(struct reboot_mode_driver *reboot);
>> +int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np);
>> int reboot_mode_unregister(struct reboot_mode_driver *reboot);
>> int devm_reboot_mode_register(struct device *dev,
>> struct reboot_mode_driver *reboot);
>>
>> --
>> 2.34.1
>>
>
On Sat, Jul 19, 2025 at 09:05:16PM +0530, Shivendra Pratap wrote:
>
>
> On 7/19/2025 12:07 AM, Dmitry Baryshkov wrote:
> > On Thu, Jul 17, 2025 at 06:16:47PM +0530, Shivendra Pratap wrote:
> >> The reboot-mode driver does not have a strict requirement for
> >> device-based registration. It primarily uses the device's of_node
> >> to read mode-<cmd> properties and the device pointer for logging.
> >>
> >> Remove the dependency on struct device and introduce support for
> >> Device Tree (DT) node-based registration. This enables drivers
> >> that are not associated with a struct device to leverage the
> >> reboot-mode framework.
> >>
> >> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
> >> ---
> >> drivers/power/reset/reboot-mode.c | 29 +++++++++++++++++++----------
> >> include/linux/reboot-mode.h | 2 +-
> >> 2 files changed, 20 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> >> index fba53f638da04655e756b5f8b7d2d666d1379535..0269ec55106472cf2f2b12bd65704dd0114bf4a3 100644
> >> --- a/drivers/power/reset/reboot-mode.c
> >> +++ b/drivers/power/reset/reboot-mode.c
> >> @@ -3,13 +3,17 @@
> >> * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> >> */
> >>
> >> +#define pr_fmt(fmt) "reboot-mode: " fmt
> >> +
> >> #include <linux/device.h>
> >> #include <linux/init.h>
> >> #include <linux/kernel.h>
> >> +#include <linux/list.h>
> >> #include <linux/module.h>
> >> #include <linux/of.h>
> >> #include <linux/reboot.h>
> >> #include <linux/reboot-mode.h>
> >> +#include <linux/slab.h>
> >>
> >> #define PREFIX "mode-"
> >>
> >> @@ -65,33 +69,35 @@ static int reboot_mode_notify(struct notifier_block *this,
> >> /**
> >> * reboot_mode_register - register a reboot mode driver
> >> * @reboot: reboot mode driver
> >> + * @np: Pointer to device tree node
> >> *
> >> * Returns: 0 on success or a negative error code on failure.
> >> */
> >> -int reboot_mode_register(struct reboot_mode_driver *reboot)
> >> +int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np)
> >> {
> >> struct mode_info *info;
> >> struct property *prop;
> >> - struct device_node *np = reboot->dev->of_node;
> >> size_t len = strlen(PREFIX);
> >> int ret;
> >>
> >> + if (!np)
> >> + return -EINVAL;
> >> +
> >> INIT_LIST_HEAD(&reboot->head);
> >>
> >> for_each_property_of_node(np, prop) {
> >> if (strncmp(prop->name, PREFIX, len))
> >> continue;
> >>
> >> - info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
> >> + info = kzalloc(sizeof(*info), GFP_KERNEL);
> >> if (!info) {
> >> ret = -ENOMEM;
> >> goto error;
> >> }
> >>
> >> if (of_property_read_u32(np, prop->name, &info->magic)) {
> >> - dev_err(reboot->dev, "reboot mode %s without magic number\n",
> >> - info->mode);
> >> - devm_kfree(reboot->dev, info);
> >> + pr_err("reboot mode %s without magic number\n", info->mode);
> >> + kfree(info);
> >> continue;
> >> }
> >>
> >> @@ -102,8 +108,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
> >> } else if (info->mode[0] == '\0') {
> >> kfree_const(info->mode);
> >> ret = -EINVAL;
> >> - dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
> >> - prop->name);
> >> + pr_err("invalid mode name(%s): too short!\n", prop->name);
> >> goto error;
> >> }
> >>
> >> @@ -130,11 +135,15 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
> >> int reboot_mode_unregister(struct reboot_mode_driver *reboot)
> >> {
> >> struct mode_info *info;
> >> + struct mode_info *next;
> >>
> >> unregister_reboot_notifier(&reboot->reboot_notifier);
> >>
> >> - list_for_each_entry(info, &reboot->head, list)
> >> + list_for_each_entry_safe(info, next, &reboot->head, list) {
> >
> > This feels liks a missing lock.
> Should we add a lock here? The list will mostly be fully created only
> once at the time of registration.
Does it matter? The code should be correct. List traversal should be
protected by the lock in all the cases.
> - thanks.
> >
> >> kfree_const(info->mode);
> >> + list_del(&info->list);
> >
> > list_del should come before kfree, otherwise it's possible to access
> > freed memory while traversing the list.
> sure. will make it list_del(&info->list) and then kfree_const(info->mode).
> - thanks.
> >
> >> + kfree(info);
> >> + }
> >>
> >> return 0;
> >> }
> >> @@ -162,7 +171,7 @@ int devm_reboot_mode_register(struct device *dev,
> >> if (!dr)
> >> return -ENOMEM;
> >>
> >> - rc = reboot_mode_register(reboot);
> >> + rc = reboot_mode_register(reboot, reboot->dev->of_node);
> >> if (rc) {
> >> devres_free(dr);
> >> return rc;
> >> diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
> >> index 4a2abb38d1d612ec0fdf05eb18c98b210f631b7f..36f071f4b82e1fc255d8dd679a18e537655c3179 100644
> >> --- a/include/linux/reboot-mode.h
> >> +++ b/include/linux/reboot-mode.h
> >> @@ -9,7 +9,7 @@ struct reboot_mode_driver {
> >> struct notifier_block reboot_notifier;
> >> };
> >>
> >> -int reboot_mode_register(struct reboot_mode_driver *reboot);
> >> +int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np);
> >> int reboot_mode_unregister(struct reboot_mode_driver *reboot);
> >> int devm_reboot_mode_register(struct device *dev,
> >> struct reboot_mode_driver *reboot);
> >>
> >> --
> >> 2.34.1
> >>
> >
--
With best wishes
Dmitry
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