@@ -1039,12 +1039,27 @@ static int svc_i3c_master_do_daa(struct i3c_master_controller *m)
if (ret)
goto rpm_out;
- /* Register all devices who participated to the core */
- for (i = 0; i < dev_nb; i++) {
- ret = i3c_master_add_i3c_dev_locked(m, addrs[i]);
- if (ret)
- goto rpm_out;
- }
+ /*
+ * Register all devices who participated to the core
+ *
+ * If two devices (A and B) are detected in DAA and address 0xa is assigned to
+ * device A and 0xb to device B, a failure in i3c_master_add_i3c_dev_locked()
+ * for device A (addr: 0xa) could prevent device B (addr: 0xb) from being
+ * registered on the bus. The I3C stack might still consider 0xb a free
+ * address. If a subsequent Hotjoin occurs, 0xb might be assigned to Device A,
+ * causing both devices A and B to use the same address 0xb, violating the I3C
+ * specification.
+ *
+ * The return value for i3c_master_add_i3c_dev_locked() should not be checked
+ * because subsequent steps will scan the entire I3C bus, independent of
+ * whether i3c_master_add_i3c_dev_locked() returns success.
+ *
+ * If device A registration fails, there is still a chance to register device
+ * B. i3c_master_add_i3c_dev_locked() can reset DAA if a failure occurs while
+ * retrieving device information.
+ */
+ for (i = 0; i < dev_nb; i++)
+ i3c_master_add_i3c_dev_locked(m, addrs[i]);
/* Configure IBI auto-rules */
ret = svc_i3c_update_ibirules(master);
svc_i3c_master_do_daa() { ... for (i = 0; i < dev_nb; i++) { ret = i3c_master_add_i3c_dev_locked(m, addrs[i]); if (ret) goto rpm_out; } } If two devices (A and B) are detected in DAA and address 0xa is assigned to device A and 0xb to device B, a failure in i3c_master_add_i3c_dev_locked() for device A (addr: 0xa) could prevent device B (addr: 0xb) from being registered on the bus. The I3C stack might still consider 0xb a free address. If a subsequent Hotjoin occurs, 0xb might be assigned to Device A, causing both devices A and B to use the same address 0xb, violating the I3C specification. The return value for i3c_master_add_i3c_dev_locked() should not be checked because subsequent steps will scan the entire I3C bus, independent of whether i3c_master_add_i3c_dev_locked() returns success. If device A registration fails, there is still a chance to register device B. i3c_master_add_i3c_dev_locked() can reset DAA if a failure occurs while retrieving device information. Cc: stable@kernel.org Fixes: 317bacf960a4 ("i3c: master: add enable(disable) hot join in sys entry") Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Frank Li <Frank.Li@nxp.com> --- change from v3 to v4 - add comments about not check return value - add miquel's review tag --- drivers/i3c/master/svc-i3c-master.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-)