esp32.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   ESP32 target API for OpenOCD                                          *
 *   Copyright (C) 2016-2019 Espressif Systems Ltd.                        *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <helper/time_support.h>
#include <target/target.h>
#include <target/target_type.h>
#include <target/smp.h>
#include <target/semihosting_common.h>
#include "assert.h"
#include "esp_xtensa_smp.h"
 
/*
This is a JTAG driver for the ESP32, the are two Tensilica cores inside
the ESP32 chip. For more information please have a look into ESP32 target
implementation.
*/
 
/* ESP32 memory map */
#define ESP32_RTC_DATA_LOW        0x50000000
#define ESP32_RTC_DATA_HIGH       0x50002000
#define ESP32_DR_REG_LOW          0x3ff00000
#define ESP32_DR_REG_HIGH         0x3ff71000
#define ESP32_SYS_RAM_LOW         0x60000000UL
#define ESP32_SYS_RAM_HIGH        (ESP32_SYS_RAM_LOW + 0x20000000UL)
#define ESP32_RTC_SLOW_MEM_BASE   ESP32_RTC_DATA_LOW
 
/* ESP32 WDT */
#define ESP32_WDT_WKEY_VALUE       0x50d83aa1
#define ESP32_TIMG0_BASE           0x3ff5f000
#define ESP32_TIMG1_BASE           0x3ff60000
#define ESP32_TIMGWDT_CFG0_OFF     0x48
#define ESP32_TIMGWDT_PROTECT_OFF  0x64
#define ESP32_TIMG0WDT_CFG0        (ESP32_TIMG0_BASE + ESP32_TIMGWDT_CFG0_OFF)
#define ESP32_TIMG1WDT_CFG0        (ESP32_TIMG1_BASE + ESP32_TIMGWDT_CFG0_OFF)
#define ESP32_TIMG0WDT_PROTECT     (ESP32_TIMG0_BASE + ESP32_TIMGWDT_PROTECT_OFF)
#define ESP32_TIMG1WDT_PROTECT     (ESP32_TIMG1_BASE + ESP32_TIMGWDT_PROTECT_OFF)
#define ESP32_RTCCNTL_BASE         0x3ff48000
#define ESP32_RTCWDT_CFG_OFF       0x8C
#define ESP32_RTCWDT_PROTECT_OFF   0xA4
#define ESP32_RTCWDT_CFG           (ESP32_RTCCNTL_BASE + ESP32_RTCWDT_CFG_OFF)
#define ESP32_RTCWDT_PROTECT       (ESP32_RTCCNTL_BASE + ESP32_RTCWDT_PROTECT_OFF)
 
#define ESP32_TRACEMEM_BLOCK_SZ    0x4000
 
/* ESP32 dport regs */
#define ESP32_DR_REG_DPORT_BASE         ESP32_DR_REG_LOW
#define ESP32_DPORT_APPCPU_CTRL_B_REG   (ESP32_DR_REG_DPORT_BASE + 0x030)
#define ESP32_DPORT_APPCPU_CLKGATE_EN   BIT(0)
/* ESP32 RTC regs */
#define ESP32_RTC_CNTL_SW_CPU_STALL_REG (ESP32_RTCCNTL_BASE + 0xac)
#define ESP32_RTC_CNTL_SW_CPU_STALL_DEF 0x0
 
/* 0 - don't care, 1 - TMS low, 2 - TMS high */
enum esp32_flash_bootstrap {
    FBS_DONTCARE = 0,
    FBS_TMSLOW,
    FBS_TMSHIGH,
};
 
struct esp32_common {
    struct esp_xtensa_smp_common esp_xtensa_smp;
    enum esp32_flash_bootstrap flash_bootstrap;
};
 
static inline struct esp32_common *target_to_esp32(struct target *target)
{
    return container_of(target->arch_info, struct esp32_common, esp_xtensa_smp);
}
 
/* Reset ESP32 peripherals.
 * Postconditions: all peripherals except RTC_CNTL are reset, CPU's PC is undefined, PRO CPU is halted,
 * APP CPU is in reset
 * How this works:
 * 0. make sure target is halted; if not, try to halt it; if that fails, try to reset it (via OCD) and then halt
 * 1. set CPU initial PC to 0x50000000 (ESP32_SMP_RTC_DATA_LOW) by clearing RTC_CNTL_{PRO,APP}CPU_STAT_VECTOR_SEL
 * 2. load stub code into ESP32_SMP_RTC_DATA_LOW; once executed, stub code will disable watchdogs and
 * make CPU spin in an idle loop.
 * 3. trigger SoC reset using RTC_CNTL_SW_SYS_RST bit
 * 4. wait for the OCD to be reset
 * 5. halt the target and wait for it to be halted (at this point CPU is in the idle loop)
 * 6. restore initial PC and the contents of ESP32_SMP_RTC_DATA_LOW
 * TODO: some state of RTC_CNTL is not reset during SW_SYS_RST. Need to reset that manually. */
 
static const uint8_t esp32_reset_stub_code[] = {
#include "../../../contrib/loaders/reset/espressif/esp32/cpu_reset_handler_code.inc"
};
 
static int esp32_soc_reset(struct target *target)
{
    int res;
    struct target_list *head;
    struct xtensa *xtensa;
 
    LOG_DEBUG("start");
    /* In order to write to peripheral registers, target must be halted first */
    if (target->state != TARGET_HALTED) {
        LOG_DEBUG("Target not halted before SoC reset, trying to halt it first");
        xtensa_halt(target);
        res = target_wait_state(target, TARGET_HALTED, 1000);
        if (res != ERROR_OK) {
            LOG_DEBUG("Couldn't halt target before SoC reset, trying to do reset-halt");
            res = xtensa_assert_reset(target);
            if (res != ERROR_OK) {
                LOG_ERROR(
                    "Couldn't halt target before SoC reset! (xtensa_assert_reset returned %d)",
                    res);
                return res;
            }
            alive_sleep(10);
            xtensa_poll(target);
            bool reset_halt_save = target->reset_halt;
            target->reset_halt = true;
            res = xtensa_deassert_reset(target);
            target->reset_halt = reset_halt_save;
            if (res != ERROR_OK) {
                LOG_ERROR(
                    "Couldn't halt target before SoC reset! (xtensa_deassert_reset returned %d)",
                    res);
                return res;
            }
            alive_sleep(10);
            xtensa_poll(target);
            xtensa_halt(target);
            res = target_wait_state(target, TARGET_HALTED, 1000);
            if (res != ERROR_OK) {
                LOG_ERROR("Couldn't halt target before SoC reset");
                return res;
            }
        }
    }
 
    if (target->smp) {
        foreach_smp_target(head, target->smp_targets) {
            xtensa = target_to_xtensa(head->target);
            /* if any of the cores is stalled unstall them */
            if (xtensa_dm_core_is_stalled(&xtensa->dbg_mod)) {
                LOG_TARGET_DEBUG(head->target, "Unstall CPUs before SW reset!");
                res = target_write_u32(target,
                    ESP32_RTC_CNTL_SW_CPU_STALL_REG,
                    ESP32_RTC_CNTL_SW_CPU_STALL_DEF);
                if (res != ERROR_OK) {
                    LOG_TARGET_ERROR(head->target, "Failed to unstall CPUs before SW reset!");
                    return res;
                }
                break;  /* both cores are unstalled now, so exit the loop */
            }
        }
    }
 
    LOG_DEBUG("Loading stub code into RTC RAM");
    uint8_t slow_mem_save[sizeof(esp32_reset_stub_code)];
 
    /* Save contents of RTC_SLOW_MEM which we are about to overwrite */
    res = target_read_buffer(target, ESP32_RTC_SLOW_MEM_BASE, sizeof(slow_mem_save), slow_mem_save);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to save contents of RTC_SLOW_MEM (%d)!", res);
        return res;
    }
 
    /* Write stub code into RTC_SLOW_MEM */
    res = target_write_buffer(target, ESP32_RTC_SLOW_MEM_BASE, sizeof(esp32_reset_stub_code), esp32_reset_stub_code);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write stub (%d)!", res);
        return res;
    }
 
    LOG_DEBUG("Resuming the target");
    xtensa = target_to_xtensa(target);
    xtensa->suppress_dsr_errors = true;
    res = xtensa_resume(target, false, ESP32_RTC_SLOW_MEM_BASE + 4, false,
        false);
    xtensa->suppress_dsr_errors = false;
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to run stub (%d)!", res);
        return res;
    }
    LOG_DEBUG("resume done, waiting for the target to come alive");
 
    /* Wait for SoC to reset */
    alive_sleep(100);
    int64_t timeout = timeval_ms() + 100;
    bool get_timeout = false;
    while (target->state != TARGET_RESET && target->state != TARGET_RUNNING) {
        alive_sleep(10);
        xtensa_poll(target);
        if (timeval_ms() >= timeout) {
            LOG_TARGET_ERROR(target, "Timed out waiting for CPU to be reset, target state=%d",
                target->state);
            get_timeout = true;
            break;
        }
    }
 
    /* Halt the CPU again */
    LOG_DEBUG("halting the target");
    xtensa_halt(target);
    res = target_wait_state(target, TARGET_HALTED, 1000);
    if (res == ERROR_OK) {
        LOG_DEBUG("restoring RTC_SLOW_MEM");
        res = target_write_buffer(target, ESP32_RTC_SLOW_MEM_BASE, sizeof(slow_mem_save), slow_mem_save);
        if (res != ERROR_OK)
            LOG_TARGET_ERROR(target, "Failed to restore contents of RTC_SLOW_MEM (%d)!", res);
    } else {
        LOG_TARGET_ERROR(target, "Timed out waiting for CPU to be halted after SoC reset");
    }
 
    return get_timeout ? ERROR_TARGET_TIMEOUT : res;
}
 
static int esp32_disable_wdts(struct target *target)
{
    /* TIMG1 WDT */
    int res = target_write_u32(target, ESP32_TIMG0WDT_PROTECT, ESP32_WDT_WKEY_VALUE);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write ESP32_TIMG0WDT_PROTECT (%d)!", res);
        return res;
    }
    res = target_write_u32(target, ESP32_TIMG0WDT_CFG0, 0);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write ESP32_TIMG0WDT_CFG0 (%d)!", res);
        return res;
    }
    /* TIMG2 WDT */
    res = target_write_u32(target, ESP32_TIMG1WDT_PROTECT, ESP32_WDT_WKEY_VALUE);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write ESP32_TIMG1WDT_PROTECT (%d)!", res);
        return res;
    }
    res = target_write_u32(target, ESP32_TIMG1WDT_CFG0, 0);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write ESP32_TIMG1WDT_CFG0 (%d)!", res);
        return res;
    }
    /* RTC WDT */
    res = target_write_u32(target, ESP32_RTCWDT_PROTECT, ESP32_WDT_WKEY_VALUE);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write ESP32_RTCWDT_PROTECT (%d)!", res);
        return res;
    }
    res = target_write_u32(target, ESP32_RTCWDT_CFG, 0);
    if (res != ERROR_OK) {
        LOG_ERROR("Failed to write ESP32_RTCWDT_CFG (%d)!", res);
        return res;
    }
    return ERROR_OK;
}
 
static int esp32_on_halt(struct target *target)
{
    int ret = esp32_disable_wdts(target);
    if (ret == ERROR_OK)
        ret = esp_xtensa_smp_on_halt(target);
    return ret;
}
 
static int esp32_arch_state(struct target *target)
{
    return ERROR_OK;
}
 
static int esp32_virt2phys(struct target *target,
    target_addr_t virtual, target_addr_t *physical)
{
    if (physical) {
        *physical = virtual;
        return ERROR_OK;
    }
    return ERROR_FAIL;
}
 
/* The TDI pin is also used as a flash Vcc bootstrap pin. If we reset the CPU externally, the last state of the TDI pin
 * can allow the power to an 1.8V flash chip to be raised to 3.3V, or the other way around. Users can use the
 * esp32 flashbootstrap command to set a level, and this routine will make sure the tdi line will return to
 * that when the jtag port is idle. */
 
static void esp32_queue_tdi_idle(struct target *target)
{
    struct esp32_common *esp32 = target_to_esp32(target);
    static uint32_t value;
    uint8_t t[4] = { 0, 0, 0, 0 };
 
    if (esp32->flash_bootstrap == FBS_TMSLOW)
        /* Make sure tdi is 0 at the exit of queue execution */
        value = 0;
    else if (esp32->flash_bootstrap == FBS_TMSHIGH)
        /* Make sure tdi is 1 at the exit of queue execution */
        value = 1;
    else
        return;
 
    /* Scan out 1 bit, do not move from IRPAUSE after we're done. */
    buf_set_u32(t, 0, 1, value);
    jtag_add_plain_ir_scan(1, t, NULL, TAP_IRPAUSE);
}
 
static int esp32_target_init(struct command_context *cmd_ctx, struct target *target)
{
    return esp_xtensa_smp_target_init(cmd_ctx, target);
}
 
static const struct xtensa_debug_ops esp32_dbg_ops = {
    .queue_enable = xtensa_dm_queue_enable,
    .queue_reg_read = xtensa_dm_queue_reg_read,
    .queue_reg_write = xtensa_dm_queue_reg_write
};
 
static const struct xtensa_power_ops esp32_pwr_ops = {
    .queue_reg_read = xtensa_dm_queue_pwr_reg_read,
    .queue_reg_write = xtensa_dm_queue_pwr_reg_write
};
 
static const struct esp_xtensa_smp_chip_ops esp32_chip_ops = {
    .reset = esp32_soc_reset,
    .on_halt = esp32_on_halt
};
 
static const struct esp_semihost_ops esp32_semihost_ops = {
    .prepare = esp32_disable_wdts
};
 
static int esp32_target_create(struct target *target, Jim_Interp *interp)
{
    struct xtensa_debug_module_config esp32_dm_cfg = {
        .dbg_ops = &esp32_dbg_ops,
        .pwr_ops = &esp32_pwr_ops,
        .tap = target->tap,
        .queue_tdi_idle = esp32_queue_tdi_idle,
        .queue_tdi_idle_arg = target
    };
 
    struct esp32_common *esp32 = calloc(1, sizeof(struct esp32_common));
    if (!esp32) {
        LOG_ERROR("Failed to alloc memory for arch info!");
        return ERROR_FAIL;
    }
 
    int ret = esp_xtensa_smp_init_arch_info(target, &esp32->esp_xtensa_smp,
        &esp32_dm_cfg, &esp32_chip_ops, &esp32_semihost_ops);
    if (ret != ERROR_OK) {
        LOG_ERROR("Failed to init arch info!");
        free(esp32);
        return ret;
    }
    esp32->flash_bootstrap = FBS_DONTCARE;
 
    /* Assume running target. If different, the first poll will fix this. */
    target->state = TARGET_RUNNING;
    target->debug_reason = DBG_REASON_NOTHALTED;
    return ERROR_OK;
}
 
static COMMAND_HELPER(esp32_cmd_flashbootstrap_do, struct esp32_common *esp32)
{
    int state = -1;
 
    if (CMD_ARGC < 1) {
        const char *st;
        state = esp32->flash_bootstrap;
        if (state == FBS_DONTCARE)
            st = "Don't care";
        else if (state == FBS_TMSLOW)
            st = "Low (3.3V)";
        else if (state == FBS_TMSHIGH)
            st = "High (1.8V)";
        else
            st = "None";
        command_print(CMD, "Current idle tms state: %s", st);
        return ERROR_OK;
    }
 
    if (!strcasecmp(CMD_ARGV[0], "none"))
        state = FBS_DONTCARE;
    else if (!strcasecmp(CMD_ARGV[0], "1.8"))
        state = FBS_TMSHIGH;
    else if (!strcasecmp(CMD_ARGV[0], "3.3"))
        state = FBS_TMSLOW;
    else if (!strcasecmp(CMD_ARGV[0], "high"))
        state = FBS_TMSHIGH;
    else if (!strcasecmp(CMD_ARGV[0], "low"))
        state = FBS_TMSLOW;
 
    if (state == -1) {
        command_print(CMD,
            "Argument unknown. Please pick one of none, high, low, 1.8 or 3.3");
        return ERROR_FAIL;
    }
    esp32->flash_bootstrap = state;
    return ERROR_OK;
}
 
COMMAND_HANDLER(esp32_cmd_flashbootstrap)
{
    struct target *target = get_current_target(CMD_CTX);
 
    if (target->smp) {
        struct target_list *head;
        struct target *curr;
        foreach_smp_target(head, target->smp_targets) {
            curr = head->target;
            int ret = CALL_COMMAND_HANDLER(esp32_cmd_flashbootstrap_do,
                target_to_esp32(curr));
            if (ret != ERROR_OK)
                return ret;
        }
        return ERROR_OK;
    }
    return CALL_COMMAND_HANDLER(esp32_cmd_flashbootstrap_do,
        target_to_esp32(target));
}
 
static const struct command_registration esp32_any_command_handlers[] = {
    {
        .name = "flashbootstrap",
        .handler = esp32_cmd_flashbootstrap,
        .mode = COMMAND_ANY,
        .help =
            "Set the idle state of the TMS pin, which at reset also is the voltage selector for the flash chip.",
        .usage = "none|1.8|3.3|high|low",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration esp32_command_handlers[] = {
    {
        .chain = esp_xtensa_smp_command_handlers,
    },
    {
        .name = "esp",
        .usage = "",
        .chain = esp32_apptrace_command_handlers,
    },
    {
        .name = "esp32",
        .usage = "",
        .chain = smp_command_handlers,
    },
    {
        .name = "esp32",
        .usage = "",
        .chain = esp32_any_command_handlers,
    },
    {
        .name = "arm",
        .mode = COMMAND_ANY,
        .help = "ARM Command Group",
        .usage = "",
        .chain = semihosting_common_handlers
    },
    COMMAND_REGISTRATION_DONE
};
 
struct target_type esp32_target = {
    .name = "esp32",
 
    .poll = esp_xtensa_smp_poll,
    .arch_state = esp32_arch_state,
 
    .halt = xtensa_halt,
    .resume = esp_xtensa_smp_resume,
    .step = esp_xtensa_smp_step,
 
    .assert_reset = esp_xtensa_smp_assert_reset,
    .deassert_reset = esp_xtensa_smp_deassert_reset,
    .soft_reset_halt = esp_xtensa_smp_soft_reset_halt,
 
    .virt2phys = esp32_virt2phys,
    .mmu = xtensa_mmu_is_enabled,
    .read_memory = xtensa_read_memory,
    .write_memory = xtensa_write_memory,
 
    .read_buffer = xtensa_read_buffer,
    .write_buffer = xtensa_write_buffer,
 
    .checksum_memory = xtensa_checksum_memory,
 
    .get_gdb_arch = xtensa_get_gdb_arch,
    .get_gdb_reg_list = xtensa_get_gdb_reg_list,
 
    .run_algorithm = xtensa_run_algorithm,
    .start_algorithm = xtensa_start_algorithm,
    .wait_algorithm = xtensa_wait_algorithm,
 
    .add_breakpoint = esp_xtensa_breakpoint_add,
    .remove_breakpoint = esp_xtensa_breakpoint_remove,
 
    .add_watchpoint = esp_xtensa_smp_watchpoint_add,
    .remove_watchpoint = esp_xtensa_smp_watchpoint_remove,
 
    .target_create = esp32_target_create,
    .init_target = esp32_target_init,
    .examine = xtensa_examine,
    .deinit_target = esp_xtensa_target_deinit,
 
    .commands = esp32_command_handlers,
};