diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/delay_timer/generic_delay_timer.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/drivers/delay_timer/generic_delay_timer.c b/drivers/delay_timer/generic_delay_timer.c new file mode 100644 index 0000000..ca522e0 --- /dev/null +++ b/drivers/delay_timer/generic_delay_timer.c @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2020, NVIDIA Corporation. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <assert.h> + +#include <arch_features.h> +#include <arch_helpers.h> +#include <common/bl_common.h> +#include <common/debug.h> +#include <drivers/delay_timer.h> +#include <drivers/generic_delay_timer.h> +#include <lib/utils_def.h> +#include <plat/common/platform.h> + +static timer_ops_t ops; + +static uint32_t get_timer_value(void) +{ + /* + * Generic delay timer implementation expects the timer to be a down + * counter. We apply bitwise NOT operator to the tick values returned + * by read_cntpct_el0() to simulate the down counter. The value is + * clipped from 64 to 32 bits. + */ + return (uint32_t)(~read_cntpct_el0()); +} + +void generic_delay_timer_init_args(uint32_t mult, uint32_t div) +{ + ops.get_timer_value = get_timer_value; + ops.clk_mult = mult; + ops.clk_div = div; + + timer_init(&ops); + + VERBOSE("Generic delay timer configured with mult=%u and div=%u\n", + mult, div); +} + +void generic_delay_timer_init(void) +{ + assert(is_armv7_gentimer_present()); + + /* Value in ticks */ + unsigned int mult = MHZ_TICKS_PER_SEC; + + /* Value in ticks per second (Hz) */ + unsigned int div = plat_get_syscnt_freq2(); + + /* Reduce multiplier and divider by dividing them repeatedly by 10 */ + while (((mult % 10U) == 0U) && ((div % 10U) == 0U)) { + mult /= 10U; + div /= 10U; + } + + generic_delay_timer_init_args(mult, div); +} + |