From 34a55b54845d01f60b614153ed6ff2c13c96cf15 Mon Sep 17 00:00:00 2001
From: Frank Li <Frank.Li@nxp.com>
Date: Wed, 2 Oct 2024 10:50:38 -0400
Subject: [PATCH] i3c: master: svc: fix possible assignment of the same address
to two devices
commit 3b2ac810d86eb96e882db80a3320a3848b133208 upstream.
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>
Link: https://lore.kernel.org/r/20241002-svc-i3c-hj-v6-6-7e6e1d3569ae@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/i3c/master/svc-i3c-master.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 130cec4ee3072..dfe11b60251ea 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1056,12 +1056,27 @@ 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);
--
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