i3c: master: Prevent reuse of dynamic address on device add failure

i3c_master_add_i3c_dev_locked() is called after a device has already
been assigned a dynamic address.  If the function fails, the address
remains marked as free and may be reallocated to another device,
leading to address conflicts on the bus.

Ensure the address is not marked as free on failure, by updating the
address slot state to prevent the address from being re-used.

Emit an error message to inform of the failure.

Opportunistically remove the !master check because it is impossible.

Note, directly resetting the device's dynamic address is no longer
an option, since Direct RSTDAA was deprecated from I3C starting from
version 1.1 and v1.1 (or later) target devices are meant to NACK it.

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/20260612080107.11606-4-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 9f8d99636f69848916e576d28eb682c604675e76..b45065ecbd48ccd84e8d2b0831a16916a221ae94 100644 (file)
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2345,12 +2345,11 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
        bool enable_ibi = false;
        int ret;
 
-       if (!master)
-               return -EINVAL;
-
        newdev = i3c_master_alloc_i3c_dev(master, &info);
-       if (IS_ERR(newdev))
-               return PTR_ERR(newdev);
+       if (IS_ERR(newdev)) {
+               ret = PTR_ERR(newdev);
+               goto err_prevent_addr_reuse;
+       }
 
        ret = i3c_master_attach_i3c_dev(master, newdev);
        if (ret)
@@ -2472,6 +2471,16 @@ err_detach_dev:
 err_free_dev:
        i3c_master_free_i3c_dev(newdev);
 
+err_prevent_addr_reuse:
+       /*
+        * Although the device has not been added, the address has been
+        * assigned. Prevent the address from being used again.
+        */
+       if (i3c_bus_get_addr_slot_status(&master->bus, addr) == I3C_ADDR_SLOT_FREE)
+               i3c_bus_set_addr_slot_status(&master->bus, addr, I3C_ADDR_SLOT_I3C_DEV);
+
+       dev_err(&master->dev, "Failed to add I3C device at address %u, error %d\n", addr, ret);
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(i3c_master_add_i3c_dev_locked);