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path: root/drivers/counter/counter-chrdev.c
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2023-09-04counter: chrdev: fix getting array extensionsFabrice Gasnier1-2/+2
When trying to watch a component array extension, and the array isn't the first extended element, it fails as the type comparison is always done on the 1st element. Fix it by indexing the 'ext' array. Example on a dummy struct counter_comp: static struct counter_comp dummy[] = { COUNTER_COMP_DIRECTION(..), ..., COUNTER_COMP_ARRAY_CAPTURE(...), }; static struct counter_count dummy_cnt = { ... .ext = dummy, .num_ext = ARRAY_SIZE(dummy), } Currently, counter_get_ext() returns -EINVAL when trying to add a watch event on one of the capture array element in such example. Fixes: d2011be1e22f ("counter: Introduce the COUNTER_COMP_ARRAY component type") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Link: https://lore.kernel.org/r/20230829134029.2402868-2-fabrice.gasnier@foss.st.com Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
2022-09-30counter: Introduce the COUNTER_COMP_ARRAY component typeWilliam Breathitt Gray1-18/+116
The COUNTER_COMP_ARRAY Counter component type is introduced to enable support for Counter array components. With Counter array components, exposure for buffers on counter devices can be defined via new Counter array component macros. This should simplify code for driver authors who would otherwise need to define individual Counter components for each array element. Eight Counter array component macros are introduced:: DEFINE_COUNTER_ARRAY_U64(_name, _length) DEFINE_COUNTER_ARRAY_CAPTURE(_name, _length) DEFINE_COUNTER_ARRAY_POLARITY(_name, _enums, _length) COUNTER_COMP_DEVICE_ARRAY_U64(_name, _read, _write, _array) COUNTER_COMP_COUNT_ARRAY_U64(_name, _read, _write, _array) COUNTER_COMP_SIGNAL_ARRAY_U64(_name, _read, _write, _array) COUNTER_COMP_ARRAY_CAPTURE(_read, _write, _array) COUNTER_COMP_ARRAY_POLARITY(_read, _write, _array) Eight Counter array callbacks are introduced as well:: int (*signal_array_u32_read)(struct counter_device *counter, struct counter_signal *signal, size_t idx, u32 *val); int (*signal_array_u32_write)(struct counter_device *counter, struct counter_signal *signal, size_t idx, u32 val); int (*device_array_u64_read)(struct counter_device *counter, size_t idx, u64 *val); int (*count_array_u64_read)(struct counter_device *counter, struct counter_count *count, size_t idx, u64 *val); int (*signal_array_u64_read)(struct counter_device *counter, struct counter_signal *signal, size_t idx, u64 *val); int (*device_array_u64_write)(struct counter_device *counter, size_t idx, u64 val); int (*count_array_u64_write)(struct counter_device *counter, struct counter_count *count, size_t idx, u64 val); int (*signal_array_u64_write)(struct counter_device *counter, struct counter_signal *signal, size_t idx, u64 val); Driver authors can handle reads/writes for an array component by receiving an element index via the `idx` parameter and processing the respective value via the `val` parameter. For example, suppose a driver wants to expose a Count's read-only capture buffer of four elements using a callback `foobar_capture_read()`:: DEFINE_COUNTER_ARRAY_CAPTURE(foobar_capture_array, 4); COUNTER_COMP_ARRAY_CAPTURE(foobar_capture_read, NULL, foobar_capture_array) Respective sysfs attributes for each array element would appear for the respective Count: * /sys/bus/counter/devices/counterX/countY/capture0 * /sys/bus/counter/devices/counterX/countY/capture1 * /sys/bus/counter/devices/counterX/countY/capture2 * /sys/bus/counter/devices/counterX/countY/capture3 If a user tries to read _capture2_ for example, `idx` will be `2` when passed to the `foobar_capture_read()` callback, and thus the driver knows which array element to handle. Counter arrays for polarity elements can be defined in a similar manner as u64 elements:: const enum counter_signal_polarity foobar_polarity_states[] = { COUNTER_SIGNAL_POLARITY_POSITIVE, COUNTER_SIGNAL_POLARITY_NEGATIVE, }; DEFINE_COUNTER_ARRAY_POLARITY(foobar_polarity_array, foobar_polarity_states, 4); COUNTER_COMP_ARRAY_POLARITY(foobar_polarity_read, foobar_polarity_write, foobar_polarity_array) Tested-by: Julien Panis <jpanis@baylibre.com> Link: https://lore.kernel.org/r/5310c22520aeae65b1b74952419f49ac4c8e1ec1.1664204990.git.william.gray@linaro.org/ Signed-off-by: William Breathitt Gray <william.gray@linaro.org> Link: https://lore.kernel.org/r/a51fd608704bdfc5a0efa503fc5481df34241e0a.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-30counter: Introduce the Signal polarity componentWilliam Breathitt Gray1-0/+1
The Signal polarity component represents the active level of a respective Signal. There are two possible states: positive (rising edge) and negative (falling edge); enum counter_signal_polarity represents these states. A convenience macro COUNTER_COMP_POLARITY() is provided for driver authors to declare a Signal polarity component. Cc: Julien Panis <jpanis@baylibre.com> Link: https://lore.kernel.org/r/8f47d6e1db71a11bb1e2666f8e2a6e9d256d4131.1664204990.git.william.gray@linaro.org/ Signed-off-by: William Breathitt Gray <william.gray@linaro.org> Link: https://lore.kernel.org/r/b6e53438badcb6318997d13dd2fc052f97d808ac.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-30counter: Move symbols into COUNTER namespaceWilliam Breathitt Gray1-1/+1
Counter subsystem symbols are only relevant to counter drivers. A COUNTER namespace is created to control the availability of these symbols to modules that import this namespace explicitly. Cc: Patrick Havelange <patrick.havelange@essensium.com> Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com> Cc: Oleksij Rempel <linux@rempel-privat.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com> Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Acked-by: David Lechner <david@lechnology.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20220815220321.74161-1-william.gray@linaro.org/ Signed-off-by: William Breathitt Gray <william.gray@linaro.org> Link: https://lore.kernel.org/r/8a756df96c24946547a7ece5caa5f654809c5e7f.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18counter: add defaults to switch-statementsTom Rix1-0/+4
Clang static analysis reports this representative problem counter-chrdev.c:482:3: warning: Undefined or garbage value returned to caller return ret; ^~~~~~~~~~ counter_get_data() has a multilevel switches, some without defaults, so ret is sometimes not set. Add returning -EINVAL similar to other defaults. Link: https://lore.kernel.org/r/20220227161746.82776-1-trix@redhat.com Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com> Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/b98d1a3ed4b0b324b261b23defd1bdddddba4d44.1647373009.git.vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21counter: Fix use-after-free race condition for events_queue_size writeWilliam Breathitt Gray1-4/+6
A race condition is possible when writing to events_queue_size where the events kfifo is freed during the execution of a kfifo_in(), resulting in a use-after-free. This patch prevents such a scenario by protecting the events queue in operation with a spinlock and locking before performing the events queue size adjustment. The existing events_lock mutex is renamed to events_out_lock to reflect that it only protects events queue out operations. Because the events queue in operations can occur in an interrupt context, a new events_in_lock spinlock is introduced and utilized. Fixes: feff17a550c7 ("counter: Implement events_queue_size sysfs attribute") Cc: David Lechner <david@lechnology.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/20211021103540.955639-1-vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21counter: Cleanup lingering atomic.h includesWilliam Breathitt Gray1-1/+0
With the removal of the chrdev_lock atomic flag, the counter-sysfs.c and counter-chrdev.c no longer needs to include the atomic.h header file. Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/20211021103514.955622-1-vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-19counter: drop chrdev_lockDavid Lechner1-6/+0
This removes the chrdev_lock from the counter subsystem. This was intended to prevent opening the chrdev more than once. However, this doesn't work in practice since userspace can duplicate file descriptors and pass file descriptors to other processes. Since this protection can't be relied on, it is best to just remove it. Suggested-by: Greg KH <gregkh@linuxfoundation.org> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: David Lechner <david@lechnology.com> Link: https://lore.kernel.org/r/20211017185521.3468640-1-david@lechnology.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-17counter: Add character device interfaceWilliam Breathitt Gray1-0/+578
This patch introduces a character device interface for the Counter subsystem. Device data is exposed through standard character device read operations. Device data is gathered when a Counter event is pushed by the respective Counter device driver. Configuration is handled via ioctl operations on the respective Counter character device node. Cc: David Lechner <david@lechnology.com> Cc: Gwendal Grignou <gwendal@chromium.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/b8b8c64b4065aedff43699ad1f0e2f8d1419c15b.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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