diff options
| author | Frank Li <Frank.Li@nxp.com> | 2024-10-02 10:50:38 -0400 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2024-10-31 23:53:39 +0100 |
| commit | 3b2ac810d86eb96e882db80a3320a3848b133208 (patch) | |
| tree | 2497a5a69e1c6c97a5b2ae465440542a32bdb93b /drivers/i3c | |
| parent | 3ca529194e292a9a9548951ed20cfd6f0c98c94d (diff) | |
| download | lwn-3b2ac810d86eb96e882db80a3320a3848b133208.tar.gz lwn-3b2ac810d86eb96e882db80a3320a3848b133208.zip | |
i3c: master: svc: fix possible assignment of the same address to two devices
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>
Diffstat (limited to 'drivers/i3c')
| -rw-r--r-- | drivers/i3c/master/svc-i3c-master.c | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c index 7ef7e50b4b91..e9c8e340d861 100644 --- a/drivers/i3c/master/svc-i3c-master.c +++ b/drivers/i3c/master/svc-i3c-master.c @@ -1103,12 +1103,27 @@ 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); |