[PATCH v12 2/8] power: reset: reboot-mode: Add support for 64 bit magic

Shivendra Pratap
2025-07-21T18:29:25Z

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 5dd3f06ca88cb28606d9fd2100ce03383c14d215..a17851a303171fd04a47e240f80687541cc85a24 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;
@@ -56,7 +55,7 @@ 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);
mutex_lock(&reboot->rb_lock);
@@ -81,6 +80,8 @@ 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)
@@ -100,12 +101,18 @@ 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