/* 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_DRAM_LOW            0x3ffae000
#define ESP32_DRAM_HIGH           0x40000000
#define ESP32_IROM_MASK_LOW       0x40000000
#define ESP32_IROM_MASK_HIGH      0x40064f00
#define ESP32_IRAM_LOW            0x40070000
#define ESP32_IRAM_HIGH           0x400a0000
#define ESP32_RTC_IRAM_LOW        0x400c0000
#define ESP32_RTC_IRAM_HIGH       0x400c2000
#define ESP32_RTC_DRAM_LOW        0x3ff80000
#define ESP32_RTC_DRAM_HIGH       0x3ff82000
#define ESP32_RTC_DATA_LOW        0x50000000
#define ESP32_RTC_DATA_HIGH       0x50002000
#define ESP32_EXTRAM_DATA_LOW     0x3f800000
#define ESP32_EXTRAM_DATA_HIGH    0x3fc00000
#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. */

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, 0, ESP32_RTC_SLOW_MEM_BASE + 4, 0, 0);
	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)
{
	return esp32_disable_wdts(target);
}

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;
}

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 = "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
};

/** Holds methods for Xtensa targets. */
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,

	.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,
};