[PATCH V3 1/3] i3c: master: Add i3c_master_do_daa_ext() for post-hibernation address recovery

[Adrian Hunter]

After system hibernation, I3C Dynamic Addresses may be reassigned at boot
and no longer match the values recorded before suspend. Introduce
i3c_master_do_daa_ext() to handle this situation.

The restore procedure is straightforward: issue a Reset Dynamic Address
Assignment (RSTDAA), then run the standard DAA sequence. The existing DAA
logic already supports detecting and updating devices whose dynamic
addresses differ from previously known values.

Refactor the DAA path by introducing a shared helper used by both the
normal i3c_master_do_daa() path and the new extended restore function,
and correct the kernel-doc in the process.

Export i3c_master_do_daa_ext() so that master drivers can invoke it from
their PM restore callbacks.

Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
---


Changes in V3:

	Rename 'restore' parameter to 'rstdaa'

Changes in V2:
	Helper function is now called i3c_master_do_daa_ext() and takes
	'restore' as an argument.
	Fix new helper function so that RSTDAA is conditional on the
	'restore' parameter.
	Subject and commit message amended accordingly.


 drivers/i3c/master.c       | 49 +++++++++++++++++++++++++++++---------
 include/linux/i3c/master.h |  1 +
 2 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 594d61edcef4..49fb6e30a68e 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1735,22 +1735,24 @@ i3c_master_register_new_i3c_devs(struct i3c_master_controller *master)
 }
 
 /**
- * i3c_master_do_daa() - do a DAA (Dynamic Address Assignment)
- * @master: master doing the DAA
+ * i3c_master_do_daa_ext() - Dynamic Address Assignment (extended version)
+ * @master: controller
+ * @rstdaa: whether to first perform Reset of Dynamic Addresses (RSTDAA)
  *
- * This function is instantiating an I3C device object and adding it to the
- * I3C device list. All device information are automatically retrieved using
- * standard CCC commands.
- *
- * The I3C device object is returned in case the master wants to attach
- * private data to it using i3c_dev_set_master_data().
+ * Perform Dynamic Address Assignment with optional support for System
+ * Hibernation (@rstdaa is true).
  *
- * This function must be called with the bus lock held in write mode.
+ * After System Hibernation, Dynamic Addresses can have been reassigned at boot
+ * time to different values. A simple strategy is followed to handle that.
+ * Perform a Reset of Dynamic Addresses (RSTDAA) followed by the normal DAA
+ * procedure which has provision for reassigning addresses that differ from the
+ * previously recorded addresses.
  *
  * Return: a 0 in case of success, an negative error code otherwise.
  */
-int i3c_master_do_daa(struct i3c_master_controller *master)
+int i3c_master_do_daa_ext(struct i3c_master_controller *master, bool rstdaa)
 {
+	int rstret = 0;
 	int ret;
 
 	ret = i3c_master_rpm_get(master);
@@ -1758,7 +1760,15 @@ int i3c_master_do_daa(struct i3c_master_controller *master)
 		return ret;
 
 	i3c_bus_maintenance_lock(&master->bus);
+
+	if (rstdaa) {
+		rstret = i3c_master_rstdaa_locked(master, I3C_BROADCAST_ADDR);
+		if (rstret == I3C_ERROR_M2)
+			rstret = 0;
+	}
+
 	ret = master->ops->do_daa(master);
+
 	i3c_bus_maintenance_unlock(&master->bus);
 
 	if (ret)
@@ -1769,7 +1779,24 @@ int i3c_master_do_daa(struct i3c_master_controller *master)
 	i3c_bus_normaluse_unlock(&master->bus);
 out:
 	i3c_master_rpm_put(master);
-	return ret;
+
+	return rstret ?: ret;
+}
+EXPORT_SYMBOL_GPL(i3c_master_do_daa_ext);
+
+/**
+ * i3c_master_do_daa() - do a DAA (Dynamic Address Assignment)
+ * @master: master doing the DAA
+ *
+ * This function instantiates I3C device objects and adds them to the
+ * I3C device list. All device information is automatically retrieved using
+ * standard CCC commands.
+ *
+ * Return: a 0 in case of success, an negative error code otherwise.
+ */
+int i3c_master_do_daa(struct i3c_master_controller *master)
+{
+	return i3c_master_do_daa_ext(master, false);
 }
 EXPORT_SYMBOL_GPL(i3c_master_do_daa);
 
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index c1ec597f655c..af2bb48363ba 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -598,6 +598,7 @@ int i3c_master_get_free_addr(struct i3c_master_controller *master,
 int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 				  u8 addr);
 int i3c_master_do_daa(struct i3c_master_controller *master);
+int i3c_master_do_daa_ext(struct i3c_master_controller *master, bool rstdaa);
 struct i3c_dma *i3c_master_dma_map_single(struct device *dev, void *ptr,
 					  size_t len, bool force_bounce,
 					  enum dma_data_direction dir);
-- 
2.51.0