All the functions operating on the 'handle' pointer are claiming it is a
pointer to const thus they should not modify the handle. In fact that's
a false statement, because first thing these functions do is drop the
cast to const with container_of:
struct acpm_info *acpm = handle_to_acpm_info(handle);
And with such cast the handle is easily writable with simple:
acpm->handle.ops.pmic_ops.read_reg = NULL;
The code is not correct logically, either, because functions like
acpm_get_by_node() and acpm_handle_put() are meant to modify the handle
reference counting, thus they must modify the handle. Modification here
happens anyway, even if the reference counting is stored in the
container which the handle is part of.
The code does not have actual visible bug, but incorrect 'const'
annotations could lead to incorrect compiler decisions.
Fixes: a88927b534 ("firmware: add Exynos ACPM protocol driver")
Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260224104203.42950-2-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Struct acpm_xfer holds two buffers with u32 commands - rxd and txd - and
counts their size by rxlen and txlen. "len" suffix is here ambiguous,
so could mean length of the buffer or length of commands, and these are
not the same since each command is u32. Rename these to rxcnt and
txcnt, and change their usage to count the number of commands in each
buffer.
This will have a benefit of allowing to use __counted_by_ptr later.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://patch.msgid.link/20260219-firmare-acpm-counted-v2-2-e1f7389237d3@oss.qualcomm.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Alive Clock and Power Manager (ACPM) Message Protocol is defined for
the purpose of communication between the ACPM firmware and masters
(AP, AOC, ...). ACPM firmware operates on the Active Power Management
(APM) module that handles overall power activities.
ACPM and masters regard each other as independent hardware component and
communicate with each other using mailbox messages and shared memory.
This protocol driver provides the interface for all the client drivers
making use of the features offered by the APM. Add ACPM protocol support.
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20250213-gs101-acpm-v9-2-8b0281b93c8b@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
