gptimer high irq priority

[Dig Kleppe]

Hi,
I want to use gpTimer 0 for high prio irq. The irq handler (assembly) is called, but after rfi i get an unhandled kernel error. I have set the timer for Freertos to timer 1. I hope someone can help.

My very stripped down C code:

Code: Select all

#include "driver/gptimer.h"

void xt_highint5( void);

void RegisterInt(void *you_need_this)
{
	gptimer_handle_t gptimer = NULL;
	gptimer_config_t timer_config = {
			.clk_src = GPTIMER_CLK_SRC_DEFAULT,
			.direction = GPTIMER_COUNT_UP,
			.resolution_hz = 1000000, // 1MHz, 1 tick=1us
	};
	ESP_ERROR_CHECK(gptimer_new_timer(&timer_config, &gptimer));

	gptimer_event_callbacks_t cbs = { .on_alarm = xt_highint5, };
	ESP_ERROR_CHECK(gptimer_register_event_callbacks(gptimer, &cbs, NULL));

	esp_intr_alloc(ETS_TG0_T0_EDGE_INTR_SOURCE, ESP_INTR_FLAG_LEVEL5|ESP_INTR_FLAG_IRAM, NULL, NULL, NULL);

	ESP_ERROR_CHECK(gptimer_enable(gptimer));

	gptimer_alarm_config_t alarm_config1 = {
		.alarm_count = 1000000, // period = 1s
	};
	ESP_ERROR_CHECK(gptimer_set_alarm_action(gptimer, &alarm_config1));
	ESP_ERROR_CHECK(gptimer_start(gptimer));

    while(1) vTaskDelay(300/portTICK_PERIOD_MS);
}

void app_main(void)
{
    xTaskCreatePinnedToCore(RegisterInt,"allocEXTGPIOINT",4096,NULL,0,NULL,0);
    while(1){
        vTaskDelay(300/portTICK_PERIOD_MS);
    }
}

Assembly code:

Code: Select all

#include <xtensa/coreasm.h>
#include <xtensa/corebits.h>
#include <xtensa/config/system.h>
#include "freertos/xtensa_context.h"
#include "esp_private/panic_reason.h"
#include "sdkconfig.h"
#include "soc/soc.h"
#include "soc/gpio_reg.h"
#include "soc/timer_group_reg.h"

#define L5_INTR_A2_OFFSET   0
#define L5_INTR_A3_OFFSET   4
#define L5_INTR_A4_OFFSET   8
#define L5_INTR_A5_OFFSET   12
#define L5_INTR_A6_OFFSET   16
#define L5_INTR_SAR_OFFSET  20
#define L5_INTR_STACK_SIZE  24
    .data
_l5_intr_stack:
    .space      L5_INTR_STACK_SIZE

pps_entry_end:

    .section .iram1,"ax"
    .global     xt_highint5
    .type       xt_highint5,@function
    .align      4

xt_highint5:

    /* Save A2, A3, A4, A5 so we can use those registers */
    movi    a0, _l5_intr_stack
    s32i    a2, a0, L5_INTR_A2_OFFSET
    s32i    a3, a0, L5_INTR_A3_OFFSET
    s32i    a4, a0, L5_INTR_A4_OFFSET
    s32i    a5, a0, L5_INTR_A5_OFFSET
    s32i    a6, a0, L5_INTR_A6_OFFSET
    rsr     a6, SAR
    s32i    a6, a0, L5_INTR_SAR_OFFSET

    movi  a2, TIMG_INT_CLR_TIMERS_REG(0)  // clr irq
    movi  a0, TIMG_T0_INT_CLR
    s32i  a0, a2, 0
    memw

exit_interrupt:

    /* Done. Restore registers and return. */
    movi    a0, _l5_intr_stack
    l32i    a2, a0, L5_INTR_SAR_OFFSET
    wsr     a2, SAR
    l32i    a2, a0, L5_INTR_A2_OFFSET
    l32i    a3, a0, L5_INTR_A3_OFFSET
    l32i    a4, a0, L5_INTR_A4_OFFSET
    l32i    a5, a0, L5_INTR_A5_OFFSET
    l32i    a6, a0, L5_INTR_A6_OFFSET
    rsync                                   /* ensure register restored */

    rsr     a0, EXCSAVE_5 // restore a0
    rfi     5

/* The linker has no reason to link in this file; all symbols it exports are already defined
   (weakly!) in the default int handler. Define a symbol here so we can use it to have the
   linker inspect this anyway. */

    .global ld_include_xt_highint5


ld_include_xt_highint5:

Error message:

[11:23:32:741] Guru Meditation Error: Core 0 panic'ed (Unhandled debug exception). ␍␊
[11:23:32:741] Debug exception reason: BREAK instr ␍␊
[11:23:32:741] Core 0 register dump:␍␊
[11:23:32:741] PC : 0x40082c94 PS : 0x00000016 A0 : 0x40080306 A1 : 0x3ffb0d00 ␍␊
[11:23:32:756] A2 : 0x3ffb6b58 A3 : 0x3ffb6c08 A4 : 0x40082c2c A5 : 0x400880d6 ␍␊
[11:23:32:756] A6 : 0x00000000 A7 : 0x00000019 A8 : 0x800831ff A9 : 0x3ffb0ce0 ␍␊
[11:23:32:772] A10 : 0x3ffb6b58 A11 : 0x3ffb0d00 A12 : 0x00000000 A13 : 0x00060023 ␍␊
[11:23:32:772] A14 : 0xb33fffff A15 : 0xb33fffff SAR : 0x00000020 EXCCAUSE: 0x00000001 ␍␊
[11:23:32:790] EXCVADDR: 0x00000000 LBEG : 0x00000000 LEND : 0x00000000 LCOUNT : 0x00000000 ␍␊

Dig

[MicroController]

The callback you register via gptimer_register_event_callbacks(...) must be a normal function, not an ISR; it is called from the GP timer driver's default ISR as a normal function, so it must adhere to the normal ABI and not use rfi to return.
See here for how an ISR for a timer would be registered using esp_intr_alloc_intrstatus(...).

[Dig Kleppe]

The irq function has to be called directly, not via the driver. This is why this function needs to be in assembly with a rfi at the end.
There are some examples that couple a GPIO to this function.See https://esp32.com/viewtopic.php?t=28008
But how to do this for the timer?