linux.git/drivers/mailbox, branch master Linux kernel source tree mailbox: mailbox-test: make data_ready a per-instance variable 2026-04-18T18:10:14+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-17T07:42:36+00:00 6e937f4e769e60947909e3525965f0137b9039e8 While not the default case, multiple tests can be run simultaneously. Then, data_ready being a global variable will be overwritten and the per-instance lock will not help. Turn the global variable into a per-instance one to avoid this problem. Fixes: e339c80af95e ("mailbox: mailbox-test: don't rely on rx_buffer content to signal data ready") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
While not the default case, multiple tests can be run simultaneously.
Then, data_ready being a global variable will be overwritten and the
per-instance lock will not help. Turn the global variable into a
per-instance one to avoid this problem.

Fixes: e339c80af95e ("mailbox: mailbox-test: don't rely on rx_buffer content to signal data ready")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: mailbox-test: initialize struct earlier 2026-04-18T18:10:14+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-17T07:42:35+00:00 bbcf9af68bfedb3d9cc3c7eae62f5c844d8b78b9 The waitqueue must be initialized before the debugfs files are created because from that time, requests from userspace can already be made. Similarily, drvdata and spinlock needs to be initialized before we request the channel, otherwise dangling irqs might run into problems like a NULL pointer exception. Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
The waitqueue must be initialized before the debugfs files are created
because from that time, requests from userspace can already be made.
Similarily, drvdata and spinlock needs to be initialized before we
request the channel, otherwise dangling irqs might run into problems
like a NULL pointer exception.

Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: mailbox-test: don't free the reused channel 2026-04-18T18:10:14+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-17T07:42:34+00:00 88ebadbf0deefdaccdab868b44ff70a0a257f473 The RX channel can be aliased to the TX channel if it has a different MMIO. This special case needs to be handled when freeing the channels otherwise a double-free occurs. Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
The RX channel can be aliased to the TX channel if it has a different
MMIO. This special case needs to be handled when freeing the channels
otherwise a double-free occurs.

Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: mailbox-test: handle channel errors consistently 2026-04-18T18:10:14+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-17T07:42:33+00:00 dd9aa1f269000d679f4ec12b32abacfc8d921413 mbox_test_request_channel() returns either an ERR_PTR or NULL. The callers, however, mostly checked for non-NULL which allows for bogus code paths when an ERR_PTR is treated like a valid channel. A later commit tried to fix it in one place but missed the other ones. Because the ERR_PTR is only used for -ENOMEM once and is converted to -EPROBE_DEFER anyhow, convert the callee to only return NULL which simplifies handling a lot and makes it less error prone. Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers") Fixes: 9b63a810c6f9 ("mailbox: mailbox-test: Fix an error check in mbox_test_probe()") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
mbox_test_request_channel() returns either an ERR_PTR or NULL. The
callers, however, mostly checked for non-NULL which allows for bogus
code paths when an ERR_PTR is treated like a valid channel. A later
commit tried to fix it in one place but missed the other ones. Because
the ERR_PTR is only used for -ENOMEM once and is converted to
-EPROBE_DEFER anyhow, convert the callee to only return NULL which
simplifies handling a lot and makes it less error prone.

Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers")
Fixes: 9b63a810c6f9 ("mailbox: mailbox-test: Fix an error check in mbox_test_probe()")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: add sanity check for channel array 2026-04-18T18:07:30+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-13T10:42:38+00:00 c1aad75595fb67edc7fda8af249d3b886efa1be9 Fail gracefully if there is no channel array attached to the mailbox controller. Otherwise the later dereference will cause an OOPS which might not be seen because mailbox controllers might instantiate very early. Remove the comment explaining the obvious while here. Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
Fail gracefully if there is no channel array attached to the mailbox
controller. Otherwise the later dereference will cause an OOPS which
might not be seen because mailbox controllers might instantiate very
early. Remove the comment explaining the obvious while here.

Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: mailbox-test: free channels on probe error 2026-04-13T01:39:02+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-10T12:53:00+00:00 c02053a9055d5fdfd32432287cca8958db1d5bc5 On probe error, free the previously obtained channels. This not only prevents a leak, but also UAF scenarios because the client structure will be removed nonetheless because it was allocated with devm. Link: https://sashiko.dev/#/patchset/20260327151217.5327-2-wsa%2Brenesas%40sang-engineering.com Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
On probe error, free the previously obtained channels. This not only
prevents a leak, but also UAF scenarios because the client structure
will be removed nonetheless because it was allocated with devm.

Link: https://sashiko.dev/#/patchset/20260327151217.5327-2-wsa%2Brenesas%40sang-engineering.com
Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: prefix new constants with MBOX_ 2026-04-13T01:04:17+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-04-10T12:49:12+00:00 0bd75b7abafb3ed199df830c539c57ef9b62c2a2 Commit 89e5d7d61600 ("mailbox: remove superfluous internal header") moved some constants to a public header but forgot to add a mailbox specific prefix. Add this now to prevent future collisions on a too generic naming. Link: https://sashiko.dev/#/patchset/20260327151112.5202-2-wsa%2Brenesas%40sang-engineering.com Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
Commit 89e5d7d61600 ("mailbox: remove superfluous internal header")
moved some constants to a public header but forgot to add a mailbox
specific prefix. Add this now to prevent future collisions on a too
generic naming.

Link: https://sashiko.dev/#/patchset/20260327151112.5202-2-wsa%2Brenesas%40sang-engineering.com
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: cix: Add IRQF_NO_SUSPEND to mailbox interrupt 2026-03-29T16:31:58+00:00 Dylan Wu fredwudi0305@gmail.com 2026-02-09T08:34:52+00:00 80784b427970219ebc338a6fb4118cde67a6c317 During the system suspend process, device interrupts are masked in the noirq phase. However, SCMI often needs to exchange final messages with the firmware to complete the power-down transition. Without the IRQF_NO_SUSPEND flag, the mailbox ISR cannot run during this late stage, leading to SCMI communication timeouts and error messages like "SCMI protocol wait for resp timeout" during suspend. Add the IRQF_NO_SUSPEND flag to the interrupt request to ensure the mailbox can continue to handle responses during the noirq stages of suspend and resume, thereby ensuring a reliable power state transition. Signed-off-by: Dylan Wu <fredwudi0305@gmail.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
During the system suspend process, device interrupts are masked in the
noirq phase. However, SCMI often needs to exchange final messages with the
firmware to complete the power-down transition. Without the IRQF_NO_SUSPEND
flag, the mailbox ISR cannot run during this late stage, leading to SCMI
communication timeouts and error messages like "SCMI protocol wait for
resp timeout" during suspend.

Add the IRQF_NO_SUSPEND flag to the interrupt request to ensure the mailbox
can continue to handle responses during the noirq stages of suspend and
resume, thereby ensuring a reliable power state transition.

Signed-off-by: Dylan Wu <fredwudi0305@gmail.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: Fix NULL message support in mbox_send_message() 2026-03-29T16:12:01+00:00 Jassi Brar jassisinghbrar@gmail.com 2026-03-27T22:00:40+00:00 c58e9456e30c7098cbcd9f04571992be8a2e4e63 The active_req field serves double duty as both the "is a TX in flight" flag (NULL means idle) and the storage for the in-flight message pointer. When a client sends NULL via mbox_send_message(), active_req is set to NULL, which the framework misinterprets as "no active request". This breaks the TX state machine by: - tx_tick() short-circuits on (!mssg), skipping the tx_done callback and the tx_complete completion - txdone_hrtimer() skips the channel entirely since active_req is NULL, so poll-based TX-done detection never fires. Fix this by introducing a MBOX_NO_MSG sentinel value that means "no active request," freeing NULL to be valid message data. The sentinel is defined in the subsystem-internal mailbox.h so that controller drivers within drivers/mailbox/ can reference it, but it is not exposed to clients outside the subsystem. Fifteen in-tree callers send NULL (doorbell-style IPCs on Qualcomm, Tegra, TI, Xilinx, i.MX, SCMI, and PCC platforms). All were audited for regression: - Most already work around the bug via knows_txdone=true with a manual mbox_client_txdone() call, making the framework's tracking irrelevant. These are unaffected. - Poll-based callers (Xilinx zynqmp/r5) are strictly better off: the poll timer now correctly detects NULL-active channels instead of silently skipping them. - irq-qcom-mpm.c was a pre-existing bug -- the only Qualcomm caller that omitted the knows_txdone + mbox_client_txdone() pattern. Fixed in a companion commit ("irqchip/qcom-mpm: Fix missing mailbox TX done acknowledgment"). - No caller sets both a tx_done callback and sends NULL, nor combines tx_block=true with NULL sends, so the newly reachable callback/completion paths are never exercised. Also update tegra-hsp's flush callback, which directly inspects active_req to wait for the channel to drain: the old "!= NULL" check becomes "!= MBOX_NO_MSG", otherwise flush spins until timeout since the sentinel is non-NULL. The only tradeoff is that 'MBOX_NO_MSG' can not be used as a message by clients. Reported-by: Joonwon Kang <joonwonkang@google.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
The active_req field serves double duty as both the "is a TX in
flight" flag (NULL means idle) and the storage for the in-flight
message pointer. When a client sends NULL via mbox_send_message(),
active_req is set to NULL, which the framework misinterprets as
"no active request". This breaks the TX state machine by:

 - tx_tick() short-circuits on (!mssg), skipping the tx_done
   callback and the tx_complete completion
 - txdone_hrtimer() skips the channel entirely since active_req
   is NULL, so poll-based TX-done detection never fires.

Fix this by introducing a MBOX_NO_MSG sentinel value that means
"no active request," freeing NULL to be valid message data. The
sentinel is defined in the subsystem-internal mailbox.h so that
controller drivers within drivers/mailbox/ can reference it, but
it is not exposed to clients outside the subsystem.

Fifteen in-tree callers send NULL (doorbell-style IPCs on Qualcomm,
Tegra, TI, Xilinx, i.MX, SCMI, and PCC platforms). All were
audited for regression:

 - Most already work around the bug via knows_txdone=true with a
   manual mbox_client_txdone() call, making the framework's
   tracking irrelevant. These are unaffected.

 - Poll-based callers (Xilinx zynqmp/r5) are strictly better off:
   the poll timer now correctly detects NULL-active channels
   instead of silently skipping them.

 - irq-qcom-mpm.c was a pre-existing bug -- the only Qualcomm
   caller that omitted the knows_txdone + mbox_client_txdone()
   pattern. Fixed in a companion commit ("irqchip/qcom-mpm: Fix
   missing mailbox TX done acknowledgment").

 - No caller sets both a tx_done callback and sends NULL, nor
   combines tx_block=true with NULL sends, so the newly reachable
   callback/completion paths are never exercised.

Also update tegra-hsp's flush callback, which directly inspects
active_req to wait for the channel to drain: the old "!= NULL"
check becomes "!= MBOX_NO_MSG", otherwise flush spins until
timeout since the sentinel is non-NULL.

The only tradeoff is that 'MBOX_NO_MSG' can not be used as a message
by clients.

Reported-by: Joonwon Kang <joonwonkang@google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
mailbox: remove superfluous internal header 2026-03-29T16:07:26+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2026-03-27T15:10:21+00:00 89e5d7d616009e5fada5da081b1d79cdd59150ab Quite some controller drivers use the defines from the internal header already. This prevents controller drivers outside the mailbox directory. Move the defines to the public controller header to allow this again as the defines are not strictly internal anyhow. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org> Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com> 
Quite some controller drivers use the defines from the internal header
already. This prevents controller drivers outside the mailbox directory.
Move the defines to the public controller header to allow this again as
the defines are not strictly internal anyhow.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>