cpu.c

/*
 * SPDX-FileCopyrightText: 2020-2024 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include "sdkconfig.h"
#include <stdint.h>
#include <assert.h>
#include "soc/soc.h"
#include "soc/soc_caps.h"
#include "hal/cpu_utility_ll.h"
#include "esp_bit_defs.h"
#include "esp_attr.h"
#include "esp_err.h"
#include "esp_cpu.h"
#if __XTENSA__
#include "xtensa/config/core-isa.h"
#else // __riscv
#include "riscv/semihosting.h"
#if SOC_CPU_HAS_FLEXIBLE_INTC
#include "riscv/instruction_decode.h"
#endif
#endif // __riscv

/* --------------------------------------------------- CPU Control -----------------------------------------------------
 *
 * ------------------------------------------------------------------------------------------------------------------ */

void esp_cpu_stall(int core_id)
{
#if SOC_CPU_CORES_NUM > 1   // We don't allow stalling of the current core
    assert(core_id >= 0 && core_id < SOC_CPU_CORES_NUM);
    cpu_utility_ll_stall_cpu(core_id);
#endif // SOC_CPU_CORES_NUM > 1
}

void esp_cpu_unstall(int core_id)
{
#if SOC_CPU_CORES_NUM > 1   // We don't allow stalling of the current core
    assert(core_id >= 0 && core_id < SOC_CPU_CORES_NUM);
    cpu_utility_ll_unstall_cpu(core_id);
#endif // SOC_CPU_CORES_NUM > 1
}

void esp_cpu_reset(int core_id)
{
    assert(core_id >= 0 && core_id < SOC_CPU_CORES_NUM);
    cpu_utility_ll_reset_cpu(core_id);
}

void esp_cpu_wait_for_intr(void)
{
#if __XTENSA__
    xt_utils_wait_for_intr();
#else
    if (esp_cpu_dbgr_is_attached() && cpu_utility_ll_wait_mode() == 0) {
        /* when SYSTEM_CPU_WAIT_MODE_FORCE_ON is disabled in WFI mode SBA access to memory does not work for debugger,
           so do not enter that mode when debugger is connected */
        return;
    }
    rv_utils_wait_for_intr();
#endif // __XTENSA__
}

/* ---------------------------------------------------- Debugging ------------------------------------------------------
 *
 * ------------------------------------------------------------------------------------------------------------------ */

// --------------- Breakpoints/Watchpoints -----------------

#if SOC_CPU_BREAKPOINTS_NUM > 0
esp_err_t esp_cpu_set_breakpoint(int bp_num, const void *bp_addr)
{
    /*
    Todo:
    - Check that bp_num is in range
    */
#if __XTENSA__
    xt_utils_set_breakpoint(bp_num, (uint32_t)bp_addr);
#else
    if (esp_cpu_dbgr_is_attached()) {
        /* If we want to set breakpoint which when hit transfers control to debugger
         * we need to set `action` in `mcontrol` to 1 (Enter Debug Mode).
         * That `action` value is supported only when `dmode` of `tdata1` is set.
         * But `dmode` can be modified by debugger only (from Debug Mode).
         *
         * So when debugger is connected we use special syscall to ask it to set breakpoint for us.
         */
        long args[] = {true, bp_num, (long)bp_addr};
        int ret = semihosting_call_noerrno(ESP_SEMIHOSTING_SYS_BREAKPOINT_SET, args);
        if (ret == 0) {
            return ESP_ERR_INVALID_RESPONSE;
        }
    } else {
        rv_utils_set_breakpoint(bp_num, (uint32_t)bp_addr);
	}
#endif // __XTENSA__
    return ESP_OK;
}

esp_err_t esp_cpu_clear_breakpoint(int bp_num)
{
    /*
    Todo:
    - Check if the bp_num is valid
    */
#if __XTENSA__
    xt_utils_clear_breakpoint(bp_num);
#else
    if (esp_cpu_dbgr_is_attached()) {
        // See description in esp_cpu_set_breakpoint()
        long args[] = {false, bp_num};
        int ret = semihosting_call_noerrno(ESP_SEMIHOSTING_SYS_BREAKPOINT_SET, args);
        if (ret == 0) {
            return ESP_ERR_INVALID_RESPONSE;
        }
    } else {
        rv_utils_clear_breakpoint(bp_num);
	}
#endif // __XTENSA__
    return ESP_OK;
}
#endif // SOC_CPU_BREAKPOINTS_NUM > 0

#if SOC_CPU_WATCHPOINTS_NUM > 0
esp_err_t esp_cpu_set_watchpoint(int wp_num, const void *wp_addr, size_t size, esp_cpu_watchpoint_trigger_t trigger)
{
    /*
    Todo:
    - Check if the wp_num is already in use
    */
    if (wp_num < 0 || wp_num >= SOC_CPU_WATCHPOINTS_NUM) {
        return ESP_ERR_INVALID_ARG;
    }

    // Check that the watched region's start address is naturally aligned to the size of the region
    if ((uint32_t)wp_addr % size) {
        return ESP_ERR_INVALID_ARG;
    }

    // Check if size is 2^n, and size is in the range of [1 ... SOC_CPU_WATCHPOINT_MAX_REGION_SIZE]
    if (size < 1 || size > SOC_CPU_WATCHPOINT_MAX_REGION_SIZE || (size & (size - 1)) != 0) {
        return ESP_ERR_INVALID_ARG;
    }
    bool on_read = (trigger == ESP_CPU_WATCHPOINT_LOAD || trigger == ESP_CPU_WATCHPOINT_ACCESS);
    bool on_write = (trigger == ESP_CPU_WATCHPOINT_STORE || trigger == ESP_CPU_WATCHPOINT_ACCESS);
#if __XTENSA__
    xt_utils_set_watchpoint(wp_num, (uint32_t)wp_addr, size, on_read, on_write);
#else
    if (esp_cpu_dbgr_is_attached()) {
        // See description in esp_cpu_set_breakpoint()
        long args[] = {true, wp_num, (long)wp_addr, (long)size,
                       (long)((on_read ? ESP_SEMIHOSTING_WP_FLG_RD : 0) | (on_write ? ESP_SEMIHOSTING_WP_FLG_WR : 0))
                      };
        int ret = semihosting_call_noerrno(ESP_SEMIHOSTING_SYS_WATCHPOINT_SET, args);
        if (ret == 0) {
            return ESP_ERR_INVALID_RESPONSE;
        }
    } else {
        rv_utils_set_watchpoint(wp_num, (uint32_t)wp_addr, size, on_read, on_write);
	}
#endif // __XTENSA__
    return ESP_OK;
}

esp_err_t esp_cpu_clear_watchpoint(int wp_num)
{
    /*
    Todo:
    - Check if the wp_num is valid
    */
#if __XTENSA__
    xt_utils_clear_watchpoint(wp_num);
#else
    if (esp_cpu_dbgr_is_attached()) {
        // See description in esp_cpu_dbgr_is_attached()
        long args[] = {false, wp_num};
        int ret = semihosting_call_noerrno(ESP_SEMIHOSTING_SYS_WATCHPOINT_SET, args);
        if (ret == 0) {
            return ESP_ERR_INVALID_RESPONSE;
        }
    } else {
        rv_utils_clear_watchpoint(wp_num);
	}
#endif // __XTENSA__
    return ESP_OK;
}
#endif // SOC_CPU_WATCHPOINTS_NUM > 0

/* ------------------------------------------------------ Misc ---------------------------------------------------------
 *
 * ------------------------------------------------------------------------------------------------------------------ */

#if __XTENSA__ && XCHAL_HAVE_S32C1I && CONFIG_SPIRAM
static DRAM_ATTR uint32_t external_ram_cas_lock = 0;
#endif

bool esp_cpu_compare_and_set(volatile uint32_t *addr, uint32_t compare_value, uint32_t new_value)
{
#if __XTENSA__
    bool ret;
#if XCHAL_HAVE_S32C1I && CONFIG_SPIRAM
    // Check if the target address is in external RAM
    if ((uint32_t)addr >= SOC_EXTRAM_DATA_LOW && (uint32_t)addr < SOC_EXTRAM_DATA_HIGH) {
        /* The target address is in external RAM, thus the native CAS instruction cannot be used. Instead, we achieve
        atomicity by disabling interrupts and then acquiring an external RAM CAS lock. */
        uint32_t intr_level;
        __asm__ __volatile__ ("rsil %0, " XTSTR(XCHAL_EXCM_LEVEL) "\n"
                              : "=r"(intr_level));
        if (!xt_utils_compare_and_set(&external_ram_cas_lock, 0, 1)) {
            // External RAM CAS lock already taken. Exit
            ret = false;
            goto exit;
        }
        // Now we compare and set the target address
        ret = (*addr == compare_value);
        if (ret) {
            *addr = new_value;
        }
        // Release the external RAM CAS lock
        external_ram_cas_lock = 0;
exit:
        // Re-enable interrupts
        __asm__ __volatile__ ("memw \n"
                              "wsr %0, ps\n"
                              :: "r"(intr_level));
    } else
#endif  // XCHAL_HAVE_S32C1I && CONFIG_SPIRAM
    {
        // The target address is in internal RAM. Use the CPU's native CAS instruction
        ret = xt_utils_compare_and_set(addr, compare_value, new_value);
    }
    return ret;

#else // __riscv
    return rv_utils_compare_and_set(addr, compare_value, new_value);
#endif
}