49580bd374
This driver, due to its limited 24-bits counter, is already tracking a cycle count in software. Allow that count to be a 64-bits value so this won't wrap in a matter of only a few seconds when the hardware clock is fast. This is very cheap to do as expensive math operations (i.e. divisions) are performed only on counter intervals whose values fit in 32 bits like before. Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
43 lines
1.6 KiB
Plaintext
43 lines
1.6 KiB
Plaintext
# Copyright (c) 2014-2015 Wind River Systems, Inc.
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# Copyright (c) 2016 Cadence Design Systems, Inc.
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# Copyright (c) 2019 Intel Corp.
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# SPDX-License-Identifier: Apache-2.0
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config CORTEX_M_SYSTICK
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bool "Cortex-M SYSTICK timer"
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depends on CPU_CORTEX_M_HAS_SYSTICK
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default y
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depends on DT_HAS_ARM_ARMV6M_SYSTICK_ENABLED || \
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DT_HAS_ARM_ARMV7M_SYSTICK_ENABLED || \
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DT_HAS_ARM_ARMV8M_SYSTICK_ENABLED || \
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DT_HAS_ARM_ARMV8_1M_SYSTICK_ENABLED
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select TICKLESS_CAPABLE
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select SYSTEM_TIMER_HAS_DISABLE_SUPPORT
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select CORTEX_M_SYSTICK_INSTALL_ISR
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help
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This module implements a kernel device driver for the Cortex-M processor
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SYSTICK timer and provides the standard "system clock driver" interfaces.
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config CORTEX_M_SYSTICK_INSTALL_ISR
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bool
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depends on CPU_CORTEX_M_HAS_SYSTICK
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help
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This option should be selected by SysTick-based drivers so that the
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sys_clock_isr() function is installed.
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config CORTEX_M_SYSTICK_64BIT_CYCLE_COUNTER
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bool "Cortex-M SYSTICK timer with sys_clock_cycle_get_64() support"
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depends on CORTEX_M_SYSTICK
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default y if (SYS_CLOCK_HW_CYCLES_PER_SEC > 60000000)
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select TIMER_HAS_64BIT_CYCLE_COUNTER
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help
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This driver, due to its limited 24-bits hardware counter, is already
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tracking a separate cycle count in software. This option make that
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count a 64-bits value to support sys_clock_cycle_get_64().
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This is cheap to do as expensive math operations (i.e. divisions)
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are performed only on counter interval values that always fit in
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32 bits.
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This is set to y by default when the hardware clock is fast enough
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to wrap sys_clock_cycle_get_32() in about a minute or less.
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