i3c: master: Ensure Hot-Join operations are stopped on shutdown

System shutdown invokes each device's bus shutdown callback to quiesce
hardware, but the I3C bus type does not currently implement one.  As a
result, on shutdown the controller's Hot-Join work and any in-flight
i3c_master_do_daa() can keep running (or be newly triggered) while the
rest of the system is being torn down.

A similar window exists at i3c_master_unregister() time: cancel_work_sync()
on hj_work prevents queued work from completing, but does not stop a
fresh Hot-Join IBI from re-queueing the worker, nor a concurrent sysfs
writer from toggling Hot-Join via i3c_set_hotjoin().

Introduce a single "shutting down" gate in the I3C core, set under the
bus maintenance lock so it is observed by any in-progress DAA path
before pending work is cancelled.  Install an i3c_bus_type shutdown
callback that engages this gate for master devices during system
shutdown, and use the same gate in i3c_master_unregister() so both
paths get identical guarantees.

Once the gate is engaged, the Hot-Join worker, i3c_master_do_daa_ext()
and i3c_set_hotjoin() all bail out cleanly, so Hot-Join IBIs that race
with shutdown become no-ops, direct DAA callers see -ENODEV, and sysfs
writers can no longer re-enable Hot-Join through ops->enable_hotjoin()
while the controller is going away.

No functional change for the steady-state runtime path; the new checks
only take effect once the controller has been marked as shutting down.

Note, this patch depends on patch "i3c: master: Consolidate Hot-Join DAA
work in the core".

Fixes: 3a379bbcea0af ("i3c: Add core I3C infrastructure")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260608054312.10604-5-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index deb5cf851940da5f247234667c3211926ee15ac7..c89a1921fcf37ca5c00b5696431b4c590797e14d 100644 (file)
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -368,14 +368,6 @@ static void i3c_device_remove(struct device *dev)
                driver->remove(i3cdev);
 }
 
-const struct bus_type i3c_bus_type = {
-       .name = "i3c",
-       .match = i3c_device_match,
-       .probe = i3c_device_probe,
-       .remove = i3c_device_remove,
-};
-EXPORT_SYMBOL_GPL(i3c_bus_type);
-
 static enum i3c_addr_slot_status
 i3c_bus_get_addr_slot_status_mask(struct i3c_bus *bus, u16 addr, u32 mask)
 {
@@ -637,7 +629,8 @@ static void i3c_master_hj_work_fn(struct work_struct *work)
 {
        struct i3c_master_controller *master = container_of(work, typeof(*master), hj_work);
 
-       i3c_master_do_daa(master);
+       if (!master->shutting_down)
+               i3c_master_do_daa(master);
 }
 
 static int i3c_set_hotjoin(struct i3c_master_controller *master, bool enable)
@@ -658,7 +651,9 @@ static int i3c_set_hotjoin(struct i3c_master_controller *master, bool enable)
 
        i3c_bus_maintenance_lock(&master->bus);
 
-       if (enable)
+       if (master->shutting_down)
+               ret = -ENODEV;
+       else if (enable)
                ret = master->ops->enable_hotjoin(master);
        else
                ret = master->ops->disable_hotjoin(master);
@@ -837,6 +832,30 @@ static const struct device_type i3c_masterdev_type = {
        .groups = i3c_masterdev_groups,
 };
 
+static void i3c_master_shutdown(struct i3c_master_controller *master)
+{
+       i3c_bus_maintenance_lock(&master->bus);
+       master->shutting_down = true;
+       i3c_bus_maintenance_unlock(&master->bus);
+
+       cancel_work_sync(&master->hj_work);
+}
+
+static void i3c_device_shutdown(struct device *dev)
+{
+       if (dev->type == &i3c_masterdev_type)
+               i3c_master_shutdown(dev_to_i3cmaster(dev));
+}
+
+const struct bus_type i3c_bus_type = {
+       .name = "i3c",
+       .match = i3c_device_match,
+       .probe = i3c_device_probe,
+       .remove = i3c_device_remove,
+       .shutdown = i3c_device_shutdown,
+};
+EXPORT_SYMBOL_GPL(i3c_bus_type);
+
 static int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
                            unsigned long max_i2c_scl_rate)
 {
@@ -1846,10 +1865,13 @@ int i3c_master_do_daa_ext(struct i3c_master_controller *master, bool rstdaa)
 
        i3c_bus_maintenance_lock(&master->bus);
 
-       if (rstdaa)
-               rstret = i3c_master_rstdaa_locked(master, I3C_BROADCAST_ADDR);
-
-       ret = master->ops->do_daa(master);
+       if (master->shutting_down) {
+               ret = -ENODEV;
+       } else {
+               if (rstdaa)
+                       rstret = i3c_master_rstdaa_locked(master, I3C_BROADCAST_ADDR);
+               ret = master->ops->do_daa(master);
+       }
 
        i3c_bus_maintenance_unlock(&master->bus);
 
@@ -3166,7 +3188,7 @@ EXPORT_SYMBOL_GPL(i3c_master_register);
 void i3c_master_unregister(struct i3c_master_controller *master)
 {
        i3c_bus_notify(&master->bus, I3C_NOTIFY_BUS_REMOVE);
-       cancel_work_sync(&master->hj_work);
+       i3c_master_shutdown(master);
 
        if (master->ops->set_dev_nack_retry)
                device_remove_file(&master->dev, &dev_attr_dev_nack_retry_count);

diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index eb5c51608bd70efd16014112d4ac473acda7a01d..77e63082b06e4111c31df4b6a287a0868fe3606b 100644 (file)
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -511,6 +511,7 @@ struct i3c_master_controller_ops {
  * @hotjoin: true if the master support hotjoin
  * @rpm_allowed: true if Runtime PM allowed
  * @rpm_ibi_allowed: true if IBI and Hot-Join allowed while runtime suspended
+ * @shutting_down: set to true when master begins shutdown or unregister
  * @boardinfo.i3c: list of I3C  boardinfo objects
  * @boardinfo.i2c: list of I2C boardinfo objects
  * @boardinfo: board-level information attached to devices connected on the bus
@@ -539,6 +540,7 @@ struct i3c_master_controller {
        unsigned int hotjoin: 1;
        unsigned int rpm_allowed: 1;
        unsigned int rpm_ibi_allowed: 1;
+       bool shutting_down;
        struct {
                struct list_head i3c;
                struct list_head i2c;