kernel/linux.git/include/linux/counter.h, branch v6.6.132

counter: linux/counter.h: fix Excess kernel-doc description warning

2024-06-12T09:12:14+00:00

[ Upstream commit 416bdb89605d960405178b9bf04df512d1ace1a3 ] Remove the @priv: line to prevent the kernel-doc warning: include/linux/counter.h:400: warning: Excess struct member 'priv' description in 'counter_device' Signed-off-by: Randy Dunlap Fixes: f2ee4759fb70 ("counter: remove old and now unused registration API") Link: https://lore.kernel.org/r/20231223050511.13849-1-rdunlap@infradead.org Signed-off-by: William Breathitt Gray Signed-off-by: Sasha Levin

counter: Declare counter_priv() to be const

2023-08-16T13:41:29+00:00

According to the gcc manual functions "whose return value is not affected by changes to the observable state of the program and that have no observable effects on such state other than to return a value may lend themselves to optimizations such as common subexpression elimination. Declaring such functions with the 'const' attribute allows GCC to avoid emitting some calls in repeated invocations of the function with the same argument values." counter_priv() is such a function and so can be marked with the const function attribute. The effect for an arm allyesconfig build according to bloat-o-meter (on top of v6.5-rc2) is: add/remove: 0/1 grow/shrink: 2/14 up/down: 524/-1064 (-540) Function old new delta rz_mtu3_count_enable_write 632 1152 +520 stm32_count_enable_write 372 376 +4 ti_eqep_action_read 456 452 -4 stm32_lptim_cnt_action_write 400 392 -8 stm32_lptim_cnt_action_read 300 288 -12 rz_mtu3_count_write 296 284 -12 rz_mtu3_count_read 304 292 -12 rz_mtu3_count_function_read 212 200 -12 rz_mtu3_count_direction_read 268 256 -12 rz_mtu3_action_read 628 616 -12 rz_mtu3_count_function_write 328 312 -16 ecap_cnt_suspend 364 340 -24 ecap_cnt_resume 300 276 -24 rz_mtu3_count_ceiling_write 596 560 -36 rz_mtu3_count_enable_read 332 288 -44 rz_mtu3_count_ceiling_read 384 340 -44 rz_mtu3_initialize_counter 792 - -792 Total: Before=60715, After=60175, chg -0.89% Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20230718162015.3940148-1-u.kleine-koenig@pengutronix.de/ Signed-off-by: William Breathitt Gray

counter: Reduce DEFINE_COUNTER_ARRAY_POLARITY() to defining counter_array

2022-10-17T13:51:29+00:00

A spare warning was reported for drivers/counter/ti-ecap-capture.c:: sparse warnings: (new ones prefixed by >>) >> drivers/counter/ti-ecap-capture.c:380:8: sparse: sparse: symbol 'ecap_cnt_pol_array' was not declared. Should it be static? vim +/ecap_cnt_pol_array +380 drivers/counter/ti-ecap-capture.c 379 > 380 static DEFINE_COUNTER_ARRAY_POLARITY(ecap_cnt_pol_array, ecap_cnt_pol_avail, ECAP_NB_CEVT); 381 The first argument to the DEFINE_COUNTER_ARRAY_POLARITY() macro is a token serving as the symbol name in the definition of a new struct counter_array structure. However, this macro actually expands to two statements:: #define DEFINE_COUNTER_ARRAY_POLARITY(_name, _enums, _length) \ DEFINE_COUNTER_AVAILABLE(_name##_available, _enums); \ struct counter_array _name = { \ .type = COUNTER_COMP_SIGNAL_POLARITY, \ .avail = &(_name##_available), \ .length = (_length), \ } Because of this, the "static" on line 380 only applies to the first statement. This patch splits out the DEFINE_COUNTER_AVAILABLE() line and leaves DEFINE_COUNTER_ARRAY_POLARITY() as a simple structure definition to avoid issues like this. Reported-by: kernel test robot Link: https://lore.kernel.org/all/202210020619.NQbyomII-lkp@intel.com/ Cc: Julien Panis Signed-off-by: William Breathitt Gray

counter: Introduce the COUNTER_COMP_ARRAY component type

2022-09-30T12:32:35+00:00

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 Link: https://lore.kernel.org/r/5310c22520aeae65b1b74952419f49ac4c8e1ec1.1664204990.git.william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/a51fd608704bdfc5a0efa503fc5481df34241e0a.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: Introduce the Count capture component

2022-09-30T12:32:35+00:00

Some devices provide a latch function to save historic Count values. This patch standardizes exposure of such functionality as Count capture components. A COUNTER_COMP_CAPTURE macro is provided for driver authors to define a capture component. A new event COUNTER_EVENT_CAPTURE is introduced to represent Count value capture events. Cc: Julien Panis Link: https://lore.kernel.org/r/c239572ab4208d0d6728136e82a88ad464369a7a.1664204990.git.william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/3cebaa0b807a225eb277d771504fe6dba7269ffd.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: Introduce the Signal polarity component

2022-09-30T12:32:35+00:00

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 Link: https://lore.kernel.org/r/8f47d6e1db71a11bb1e2666f8e2a6e9d256d4131.1664204990.git.william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/b6e53438badcb6318997d13dd2fc052f97d808ac.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: Realign counter_comp comment block to 80 characters

2022-09-22T11:28:31+00:00

The member documentation comment lines for struct counter_comp extend past the 80-characters column boundary due to extra identation at the start of each section. This patch realigns the comment block within the 80-characters boundary by removing these superfluous indents. Reviewed-by: Yanteng Si Link: https://lore.kernel.org/r/20220902120839.4260-1-william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/8294b04153c33602e9c3dd21ac90c1e99bd0fdaf.1663844776.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: remove old and now unused registration API

2021-12-30T16:44:07+00:00

Usage of counter_register() yields issues in device lifetime tracking. All drivers were converted to the new API, so the old one can go away. Reviewed-by: Jonathan Cameron Acked-by: William Breathitt Gray Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-24-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

counter: Provide alternative counter registration functions

2021-12-30T16:44:06+00:00

The current implementation gets device lifetime tracking wrong. The problem is that allocation of struct counter_device is controlled by the individual drivers but this structure contains a struct device that might have to live longer than a driver is bound. As a result a command sequence like: { sleep 5; echo bang; } > /dev/counter0 & sleep 1; echo 40000000.timer:counter > /sys/bus/platform/drivers/stm32-timer-counter/unbind can keep a reference to the struct device and unbinding results in freeing the memory occupied by this device resulting in an oops. This commit provides two new functions (plus some helpers): - counter_alloc() to allocate a struct counter_device that is automatically freed once the embedded struct device is released - counter_add() to register such a device. Note that this commit doesn't fix any issues, all drivers have to be converted to these new functions to correct the lifetime problems. Reviewed-by: Jonathan Cameron Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-14-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

counter: Provide a wrapper to access device private data

2021-12-30T16:44:06+00:00

For now this just wraps accessing struct counter_device::priv. However this is about to change and converting drivers to this helper individually makes fixing device lifetime issues result in easier to review patches. Reviewed-by: Jonathan Cameron Acked-by: William Breathitt Gray Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-5-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman