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| 1 | +/* |
| 2 | + * Copyright (c) 2024 Texas Instruments Incorporated |
| 3 | + * Copyright (c) 2024 BayLibre, SAS |
| 4 | + * |
| 5 | + * SPDX-License-Identifier: Apache-2.0 |
| 6 | + */ |
| 7 | + |
| 8 | +#define DT_DRV_COMPAT ti_cc23x0_systim_timer |
| 9 | + |
| 10 | +/* |
| 11 | + * TI SimpleLink CC23X0 timer driver based on SYSTIM |
| 12 | + */ |
| 13 | + |
| 14 | +#include <soc.h> |
| 15 | + |
| 16 | +#include <zephyr/device.h> |
| 17 | +#include <zephyr/drivers/clock_control.h> |
| 18 | +#include <zephyr/drivers/timer/system_timer.h> |
| 19 | +#include <zephyr/irq.h> |
| 20 | +#include <zephyr/spinlock.h> |
| 21 | +#include <zephyr/sys_clock.h> |
| 22 | +#include <zephyr/sys/util.h> |
| 23 | + |
| 24 | +#include <inc/hw_types.h> |
| 25 | +#include <inc/hw_memmap.h> |
| 26 | +#include <inc/hw_systim.h> |
| 27 | +#include <inc/hw_evtsvt.h> |
| 28 | + |
| 29 | +/* Kernel tick period in microseconds (same timebase as systim) */ |
| 30 | +#define TICK_PERIOD_MICRO_SEC (1000000 / CONFIG_SYS_CLOCK_TICKS_PER_SEC) |
| 31 | + |
| 32 | +/* |
| 33 | + * Max number of systim ticks into the future |
| 34 | + * |
| 35 | + * Under the hood, the kernel timer uses the SysTimer whose events trigger |
| 36 | + * immediately if the compare value is less than 2^22 systimer ticks in the past |
| 37 | + * (4.194sec at 1us resolution). Therefore, the max number of SysTimer ticks you |
| 38 | + * can schedule into the future is 2^32 - 2^22 - 1 ticks (~= 4290 sec at 1us |
| 39 | + * resolution). |
| 40 | + */ |
| 41 | +#define SYSTIM_TIMEOUT_MAX 0xFFBFFFFFU |
| 42 | + |
| 43 | +/* Set systim interrupt to lowest priority */ |
| 44 | +#define SYSTIM_ISR_PRIORITY 3U |
| 45 | + |
| 46 | +/* Keep track of systim counter at previous announcement to the kernel */ |
| 47 | +static uint32_t last_systim_count; |
| 48 | + |
| 49 | +static void systim_isr(const void *arg); |
| 50 | +static int sys_clock_driver_init(void); |
| 51 | + |
| 52 | +/* |
| 53 | + * Set system clock timeout. |
| 54 | + */ |
| 55 | +void sys_clock_set_timeout(int32_t ticks, bool idle) |
| 56 | +{ |
| 57 | + ARG_UNUSED(idle); |
| 58 | + |
| 59 | + /* If timeout is necessary */ |
| 60 | + if (ticks != K_TICKS_FOREVER) { |
| 61 | + /* Get current value as early as possible */ |
| 62 | + uint32_t now_tick = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U); |
| 63 | + uint32_t timeout = ticks * TICK_PERIOD_MICRO_SEC; |
| 64 | + |
| 65 | + if (timeout > SYSTIM_TIMEOUT_MAX) { |
| 66 | + timeout = SYSTIM_TIMEOUT_MAX; |
| 67 | + } |
| 68 | + /* This should wrap around */ |
| 69 | + HWREG(SYSTIM_BASE + SYSTIM_O_CH0CC) = now_tick + timeout; |
| 70 | + } |
| 71 | +} |
| 72 | + |
| 73 | +uint32_t sys_clock_elapsed(void) |
| 74 | +{ |
| 75 | + /* Get current value as early as possible */ |
| 76 | + uint32_t current_systim_count = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U); |
| 77 | + uint32_t elapsed_systim; |
| 78 | + |
| 79 | + if (current_systim_count >= last_systim_count) { |
| 80 | + elapsed_systim = current_systim_count - last_systim_count; |
| 81 | + } else { |
| 82 | + elapsed_systim = (UINT32_MAX - last_systim_count) + current_systim_count; |
| 83 | + } |
| 84 | + |
| 85 | + int32_t elapsed_ticks = elapsed_systim / TICK_PERIOD_MICRO_SEC; |
| 86 | + |
| 87 | + return elapsed_ticks; |
| 88 | +} |
| 89 | + |
| 90 | +uint32_t sys_clock_cycle_get_32(void) |
| 91 | +{ |
| 92 | + return HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U); |
| 93 | +} |
| 94 | + |
| 95 | +void systim_isr(const void *arg) |
| 96 | +{ |
| 97 | + /* Get current value as early as possible */ |
| 98 | + uint32_t current_systim_count = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U); |
| 99 | + uint32_t elapsed_systim; |
| 100 | + |
| 101 | + if (current_systim_count >= last_systim_count) { |
| 102 | + elapsed_systim = current_systim_count - last_systim_count; |
| 103 | + } else { |
| 104 | + elapsed_systim = (UINT32_MAX - last_systim_count) + current_systim_count; |
| 105 | + } |
| 106 | + |
| 107 | + int32_t elapsed_ticks = elapsed_systim / TICK_PERIOD_MICRO_SEC; |
| 108 | + |
| 109 | + sys_clock_announce(elapsed_ticks); |
| 110 | + |
| 111 | + last_systim_count = current_systim_count; |
| 112 | + |
| 113 | + /* Do not re-arm systim. Zephyr will do so through sys_clock_set_timeout */ |
| 114 | +} |
| 115 | + |
| 116 | +static int sys_clock_driver_init(void) |
| 117 | +{ |
| 118 | + uint32_t now_tick; |
| 119 | + |
| 120 | + /* Get current value as early as possible */ |
| 121 | + now_tick = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U); |
| 122 | + last_systim_count = now_tick; |
| 123 | + |
| 124 | + /* Clear any pending interrupts on SysTimer channel 0 */ |
| 125 | + HWREG(SYSTIM_BASE + SYSTIM_O_ICLR) = SYSTIM_ICLR_EV0_CLR; |
| 126 | + |
| 127 | + /* |
| 128 | + * Configure SysTimer channel 0 to compare mode with timer |
| 129 | + * resolution of 1 us. |
| 130 | + */ |
| 131 | + HWREG(SYSTIM_BASE + SYSTIM_O_CH0CFG) = 0; |
| 132 | + |
| 133 | + /* Make SysTimer halt on CPU debug halt */ |
| 134 | + HWREG(SYSTIM_BASE + SYSTIM_O_EMU) = SYSTIM_EMU_HALT_STOP; |
| 135 | + |
| 136 | + HWREG(EVTSVT_BASE + EVTSVT_O_CPUIRQ16SEL) = EVTSVT_CPUIRQ16SEL_PUBID_SYSTIM0; |
| 137 | + |
| 138 | + /* |
| 139 | + * Set IMASK for channel 0. IMASK is used by the power driver to know |
| 140 | + * which systimer channels are active. |
| 141 | + */ |
| 142 | + HWREG(SYSTIM_BASE + SYSTIM_O_IMSET) = SYSTIM_IMSET_EV0_SET; |
| 143 | + |
| 144 | + /* This should wrap around and set a maximum timeout */ |
| 145 | + HWREG(SYSTIM_BASE + SYSTIM_O_CH0CC) = now_tick + SYSTIM_TIMEOUT_MAX; |
| 146 | + |
| 147 | + /* Take configurable interrupt IRQ16 for systimer */ |
| 148 | + IRQ_CONNECT(CPUIRQ16_IRQn, SYSTIM_ISR_PRIORITY, systim_isr, 0, 0); |
| 149 | + irq_enable(CPUIRQ16_IRQn); |
| 150 | + |
| 151 | + return 0; |
| 152 | +} |
| 153 | + |
| 154 | +SYS_INIT(sys_clock_driver_init, PRE_KERNEL_2, CONFIG_SYSTEM_CLOCK_INIT_PRIORITY); |
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