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drivers: dp: swdp_bitbang: Update SWD clock calculation 

This patch updates the SWD clock calculation to the latest behavior
of DAPLink.

Signed-off-by: Maximilian Deubel <maximilian.deubel@nordicsemi.no>
This commit is contained in:
Maximilian Deubel 2024-10-02 13:53:31 +02:00 committed by Fabio Baltieri
parent 621a6000d5
commit fd686a25b3
1 changed files with 16 additions and 11 deletions
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27
drivers/dp/swdp_bitbang.c
View File

@ -26,8 +26,8 @@
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(swdp, CONFIG_DP_DRIVER_LOG_LEVEL);
#define CLOCK_DELAY(swclk_freq, port_write_cycles) \
((CPU_CLOCK / 2 / swclk_freq) - port_write_cycles)
#define MAX_SWJ_CLOCK(delay_cycles, port_write_cycles) \
((CPU_CLOCK / 2U) / (port_write_cycles + delay_cycles))
/*
* Default SWCLK frequency in Hz.
@ -35,6 +35,7 @@ LOG_MODULE_REGISTER(swdp, CONFIG_DP_DRIVER_LOG_LEVEL);
*/
#define SWDP_DEFAULT_SWCLK_FREQUENCY 1000000U
#define DELAY_FAST_CYCLES 2U
#define DELAY_SLOW_CYCLES 3U
struct sw_config {
@ -528,14 +529,19 @@ static int sw_set_clock(const struct device *dev, const uint32_t clock)
struct sw_cfg_data *sw_data = dev->data;
uint32_t delay;
sw_data->fast_clock = false;
delay = ((CPU_CLOCK / 2U) + (clock - 1U)) / clock;
if (delay > config->port_write_cycles) {
delay -= config->port_write_cycles;
delay = (delay + (DELAY_SLOW_CYCLES - 1U)) / DELAY_SLOW_CYCLES;
} else {
if (clock >= MAX_SWJ_CLOCK(DELAY_FAST_CYCLES, config->port_write_cycles)) {
sw_data->fast_clock = true;
delay = 1U;
} else {
sw_data->fast_clock = false;
delay = ((CPU_CLOCK / 2U) + (clock - 1U)) / clock;
if (delay > config->port_write_cycles) {
delay -= config->port_write_cycles;
delay = (delay + (DELAY_SLOW_CYCLES - 1U)) / DELAY_SLOW_CYCLES;
} else {
delay = 1U;
}
}
sw_data->clock_delay = delay;
@ -666,8 +672,7 @@ static int sw_gpio_init(const struct device *dev)
sw_data->turnaround = 1U;
sw_data->data_phase = false;
sw_data->fast_clock = false;
sw_data->clock_delay = CLOCK_DELAY(SWDP_DEFAULT_SWCLK_FREQUENCY,
config->port_write_cycles);
sw_set_clock(dev, SWDP_DEFAULT_SWCLK_FREQUENCY);
return 0;
}