openocd/src/target/arc_jtag.c

/* SPDX-License-Identifier: GPL-2.0-or-later */

/***************************************************************************
 *   Copyright (C) 2013-2014,2019-2020 Synopsys, Inc.                      *
 *   Frank Dols <frank.dols@synopsys.com>                                  *
 *   Mischa Jonker <mischa.jonker@synopsys.com>                            *
 *   Anton Kolesov <anton.kolesov@synopsys.com>                            *
 *   Evgeniy Didin <didin@synopsys.com>                                    *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "arc.h"

/*
 * This functions sets instruction register in TAP. TAP end state is always
 * IRPAUSE.
 *
 * @param jtag_info
 * @param new_instr	Instruction to write to instruction register.
 */
static void arc_jtag_enque_write_ir(struct arc_jtag *jtag_info, uint32_t
		new_instr)
{
	uint32_t current_instr;
	struct jtag_tap *tap;
	uint8_t instr_buffer[sizeof(uint32_t)] = {0};

	assert(jtag_info);
	assert(jtag_info->tap);

	tap = jtag_info->tap;

	/* Do not set instruction if it is the same as current. */
	current_instr = buf_get_u32(tap->cur_instr, 0, tap->ir_length);
	if (current_instr == new_instr)
		return;

	struct scan_field field = {
		.num_bits = tap->ir_length,
		.out_value = instr_buffer
	};
	buf_set_u32(instr_buffer, 0, field.num_bits, new_instr);

	/* From code in src/jtag/drivers/driver.c it look like that fields are
	 * copied so it is OK that field in this function is allocated in stack and
	 * thus this memory will be repurposed before jtag_execute_queue() will be
	 * invoked. */
	jtag_add_ir_scan(tap, &field, TAP_IRPAUSE);
}

/**
 * Read 4-byte word from data register.
 *
 * Unlike arc_jtag_write_data, this function returns byte-buffer, caller must
 * convert this data to required format himself. This is done, because it is
 * impossible to convert data before jtag_execute_queue() is invoked, so it
 * cannot be done inside this function, so it has to operate with
 * byte-buffers. Write function on the other hand can "write-and-forget", data
 * is converted to byte-buffer before jtag_execute_queue().
 *
 * @param jtag_info
 * @param data		Array of bytes to read into.
 * @param end_state	End state after reading.
 */
static void arc_jtag_enque_read_dr(struct arc_jtag *jtag_info, uint8_t *data,
		tap_state_t end_state)
{

	assert(jtag_info);
	assert(jtag_info->tap);

	struct scan_field field = {
		.num_bits = 32,
		.in_value = data
	};

	jtag_add_dr_scan(jtag_info->tap, 1, &field, end_state);
}

/**
 * Write 4-byte word to data register.
 *
 * @param jtag_info
 * @param data		4-byte word to write into data register.
 * @param end_state	End state after writing.
 */
static void arc_jtag_enque_write_dr(struct arc_jtag *jtag_info, uint32_t data,
		tap_state_t end_state)
{
	uint8_t out_value[sizeof(uint32_t)] = {0};

	assert(jtag_info);
	assert(jtag_info->tap);

	buf_set_u32(out_value, 0, 32, data);

	struct scan_field field = {
		.num_bits = 32,
		.out_value = out_value
	};

	jtag_add_dr_scan(jtag_info->tap, 1, &field, end_state);
}


/**
 * Set transaction in command register. This function sets instruction register
 * and then transaction register, there is no need to invoke write_ir before
 * invoking this function.
 *
 * @param jtag_info
 * @param new_trans	Transaction to write to transaction command register.
 * @param end_state	End state after writing.
 */
static void arc_jtag_enque_set_transaction(struct arc_jtag *jtag_info,
		uint32_t new_trans, tap_state_t end_state)
{
	uint8_t out_value[sizeof(uint32_t)] = {0};

	assert(jtag_info);
	assert(jtag_info->tap);

	/* No need to do anything. */
	if (jtag_info->cur_trans == new_trans)
		return;

	/* Set instruction. We used to call write_ir at upper levels, however
	 * write_ir-write_transaction were constantly in pair, so to avoid code
	 * duplication this function does it self. For this reasons it is "set"
	 * instead of "write". */
	arc_jtag_enque_write_ir(jtag_info, ARC_TRANSACTION_CMD_REG);
	buf_set_u32(out_value, 0, ARC_TRANSACTION_CMD_REG_LENGTH, new_trans);
	struct scan_field field = {
		.num_bits = ARC_TRANSACTION_CMD_REG_LENGTH,
		.out_value = out_value
	};

	jtag_add_dr_scan(jtag_info->tap, 1, &field, end_state);
	jtag_info->cur_trans = new_trans;
}

/**
 * Run reset through transaction set. None of the previous
 * settings/commands/etc. are used anymore (or no influence).
 */
static void arc_jtag_enque_reset_transaction(struct arc_jtag *jtag_info)
{
	arc_jtag_enque_set_transaction(jtag_info, ARC_JTAG_CMD_NOP, TAP_IDLE);
}

static void arc_jtag_enque_status_read(struct arc_jtag * const jtag_info,
	uint8_t * const buffer)
{
	assert(jtag_info);
	assert(jtag_info->tap);
	assert(buffer);

	/* first writing code(0x8) of jtag status register in IR */
	arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_STATUS_REG);
	/* Now reading dr performs jtag status register read */
	arc_jtag_enque_read_dr(jtag_info, buffer, TAP_IDLE);
}

/* ----- Exported JTAG functions ------------------------------------------- */

int arc_jtag_startup(struct arc_jtag *jtag_info)
{
	assert(jtag_info);

	arc_jtag_enque_reset_transaction(jtag_info);

	return jtag_execute_queue();
}

/** Read STATUS register. */
int arc_jtag_status(struct arc_jtag * const jtag_info, uint32_t * const value)
{
	uint8_t buffer[sizeof(uint32_t)];

	assert(jtag_info);
	assert(jtag_info->tap);

	/* Fill command queue. */
	arc_jtag_enque_reset_transaction(jtag_info);
	arc_jtag_enque_status_read(jtag_info, buffer);
	arc_jtag_enque_reset_transaction(jtag_info);

	/* Execute queue. */
	CHECK_RETVAL(jtag_execute_queue());

	/* Parse output. */
	*value = buf_get_u32(buffer, 0, 32);

	return ERROR_OK;
}
/* Helper function: Adding read/write register operation to queue */
static void arc_jtag_enque_register_rw(struct arc_jtag *jtag_info, uint32_t *addr,
	uint8_t *read_buffer, const uint32_t *write_buffer, uint32_t count)
{
	uint32_t i;

	for (i = 0; i < count; i++) {
		/* ARC jtag has optimization which is to increment ADDRESS_REG performing
		 * each transaction. Making sequential reads/writes we can set address for
		 * only first register in sequence, and than do read/write in cycle. */
		if (i == 0 || (addr[i] != addr[i-1] + 1)) {
			arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_ADDRESS_REG);
			/* Going to TAP_IDLE state we initiate jtag transaction.
			 * Reading data we must go to TAP_IDLE, because further
			 * the data would be read. In case of write we go to TAP_DRPAUSE,
			 * because we need to write data to Data register first. */
			if (write_buffer)
				arc_jtag_enque_write_dr(jtag_info, addr[i], TAP_DRPAUSE);
			else
				arc_jtag_enque_write_dr(jtag_info, addr[i], TAP_IDLE);
			arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_DATA_REG);
		}
		if (write_buffer)
			arc_jtag_enque_write_dr(jtag_info, *(write_buffer + i), TAP_IDLE);
		else
			arc_jtag_enque_read_dr(jtag_info, read_buffer + i * 4, TAP_IDLE);
	}
	/* To prevent pollution of next register due to optimization it is necessary *
	 * to reset transaction */
	arc_jtag_enque_reset_transaction(jtag_info);
}

/**
 * Write registers. addr is an array of addresses, and those addresses can be
 * in any order, though it is recommended that they are in sequential order
 * where possible, as this reduces number of JTAG commands to transfer.
 *
 * @param jtag_info
 * @param type		Type of registers to write: core or aux.
 * @param addr		Array of registers numbers.
 * @param count		Amount of registers in arrays.
 * @param buffer	Array of register values.
 */
static int arc_jtag_write_registers(struct arc_jtag *jtag_info, uint32_t type,
	uint32_t *addr, uint32_t count, const uint32_t *buffer)
{
	LOG_DEBUG("Writing to %s registers: addr[0]=0x%" PRIx32 ";count=%" PRIu32
			  ";buffer[0]=0x%08" PRIx32,
		(type == ARC_JTAG_CORE_REG ? "core" : "aux"), *addr, count, *buffer);

	if (!count) {
		LOG_ERROR("Trying to write 0 registers");
		return ERROR_FAIL;
	}

	arc_jtag_enque_reset_transaction(jtag_info);

	/* What registers are we writing to? */
	const uint32_t transaction = (type == ARC_JTAG_CORE_REG ?
			ARC_JTAG_WRITE_TO_CORE_REG : ARC_JTAG_WRITE_TO_AUX_REG);
	arc_jtag_enque_set_transaction(jtag_info, transaction, TAP_DRPAUSE);

	arc_jtag_enque_register_rw(jtag_info, addr, NULL, buffer, count);

	return jtag_execute_queue();
}

/**
 * Read registers. addr is an array of addresses, and those addresses can be in
 * any order, though it is recommended that they are in sequential order where
 * possible, as this reduces number of JTAG commands to transfer.
 *
 * @param jtag_info
 * @param type		Type of registers to read: core or aux.
 * @param addr		Array of registers numbers.
 * @param count		Amount of registers in arrays.
 * @param buffer	Array of register values.
 */
static int arc_jtag_read_registers(struct arc_jtag *jtag_info, uint32_t type,
		uint32_t *addr, uint32_t count, uint32_t *buffer)
{
	int retval;
	uint32_t i;

	assert(jtag_info);
	assert(jtag_info->tap);

	LOG_DEBUG("Reading %s registers: addr[0]=0x%" PRIx32 ";count=%" PRIu32,
		(type == ARC_JTAG_CORE_REG ? "core" : "aux"), *addr, count);

	if (!count) {
		LOG_ERROR("Trying to read 0 registers");
		return ERROR_FAIL;
	}

	arc_jtag_enque_reset_transaction(jtag_info);

	/* What type of registers we are reading? */
	const uint32_t transaction = (type == ARC_JTAG_CORE_REG ?
			ARC_JTAG_READ_FROM_CORE_REG : ARC_JTAG_READ_FROM_AUX_REG);
	arc_jtag_enque_set_transaction(jtag_info, transaction, TAP_DRPAUSE);

	uint8_t *data_buf = calloc(sizeof(uint8_t), count * 4);

	arc_jtag_enque_register_rw(jtag_info, addr, data_buf, NULL, count);

	retval = jtag_execute_queue();
	if (retval != ERROR_OK) {
		LOG_ERROR("Failed to execute jtag queue: %d", retval);
		retval = ERROR_FAIL;
		goto exit;
	}

	/* Convert byte-buffers to host /presentation. */
	for (i = 0; i < count; i++)
		buffer[i] = buf_get_u32(data_buf + 4 * i, 0, 32);

	LOG_DEBUG("Read from register: buf[0]=0x%" PRIx32, buffer[0]);

exit:
	free(data_buf);

	return retval;
}


/** Wrapper function to ease writing of one core register. */
int arc_jtag_write_core_reg_one(struct arc_jtag *jtag_info, uint32_t addr,
	uint32_t value)
{
	return arc_jtag_write_core_reg(jtag_info, &addr, 1, &value);
}

/**
 * Write core registers. addr is an array of addresses, and those addresses can
 * be in any order, though it is recommended that they are in sequential order
 * where possible, as this reduces number of JTAG commands to transfer.
 *
 * @param jtag_info
 * @param addr		Array of registers numbers.
 * @param count		Amount of registers in arrays.
 * @param buffer	Array of register values.
 */
int arc_jtag_write_core_reg(struct arc_jtag *jtag_info, uint32_t *addr,
	uint32_t count, const uint32_t *buffer)
{
	return arc_jtag_write_registers(jtag_info, ARC_JTAG_CORE_REG, addr, count,
			buffer);
}

/** Wrapper function to ease reading of one core register. */
int arc_jtag_read_core_reg_one(struct arc_jtag *jtag_info, uint32_t addr,
	uint32_t *value)
{
	return arc_jtag_read_core_reg(jtag_info, &addr, 1, value);
}

/**
 * Read core registers. addr is an array of addresses, and those addresses can
 * be in any order, though it is recommended that they are in sequential order
 * where possible, as this reduces number of JTAG commands to transfer.
 *
 * @param jtag_info
 * @param addr		Array of core register numbers.
 * @param count		Amount of registers in arrays.
 * @param buffer	Array of register values.
 */
int arc_jtag_read_core_reg(struct arc_jtag *jtag_info, uint32_t *addr,
	uint32_t count, uint32_t *buffer)
{
	return arc_jtag_read_registers(jtag_info, ARC_JTAG_CORE_REG, addr, count,
			buffer);
}

/** Wrapper function to ease writing of one AUX register. */
int arc_jtag_write_aux_reg_one(struct arc_jtag *jtag_info, uint32_t addr,
	uint32_t value)
{
	return arc_jtag_write_aux_reg(jtag_info, &addr, 1, &value);
}

/**
 * Write AUX registers. addr is an array of addresses, and those addresses can
 * be in any order, though it is recommended that they are in sequential order
 * where possible, as this reduces number of JTAG commands to transfer.
 *
 * @param jtag_info
 * @param addr		Array of registers numbers.
 * @param count		Amount of registers in arrays.
 * @param buffer	Array of register values.
 */
int arc_jtag_write_aux_reg(struct arc_jtag *jtag_info, uint32_t *addr,
	uint32_t count, const uint32_t *buffer)
{
	return arc_jtag_write_registers(jtag_info, ARC_JTAG_AUX_REG, addr, count,
			buffer);
}

/** Wrapper function to ease reading of one AUX register. */
int arc_jtag_read_aux_reg_one(struct arc_jtag *jtag_info, uint32_t addr,
	uint32_t *value)
{
	return arc_jtag_read_aux_reg(jtag_info, &addr, 1, value);
}

/**
 * Read AUX registers. addr is an array of addresses, and those addresses can
 * be in any order, though it is recommended that they are in sequential order
 * where possible, as this reduces number of JTAG commands to transfer.
 *
 * @param jtag_info
 * @param addr		Array of AUX register numbers.
 * @param count		Amount of registers in arrays.
 * @param buffer	Array of register values.
 */
int arc_jtag_read_aux_reg(struct arc_jtag *jtag_info, uint32_t *addr,
	uint32_t count, uint32_t *buffer)
{
	return arc_jtag_read_registers(jtag_info, ARC_JTAG_AUX_REG, addr, count,
			buffer);
}

/**
 * Write a sequence of 4-byte words into target memory.
 *
 * We can write only 4byte words via JTAG, so any non-word writes should be
 * handled at higher levels by read-modify-write.
 *
 * This function writes directly to the memory, leaving any caches (if there
 * are any) in inconsistent state. It is responsibility of upper level to
 * resolve this.
 *
 * @param jtag_info
 * @param addr		Address of first word to write into.
 * @param count		Amount of word to write.
 * @param buffer	Array to write into memory.
 */
int arc_jtag_write_memory(struct arc_jtag *jtag_info, uint32_t addr,
		uint32_t count, const uint32_t *buffer)
{
	assert(jtag_info);
	assert(buffer);

	LOG_DEBUG("Writing to memory: addr=0x%08" PRIx32 ";count=%" PRIu32 ";buffer[0]=0x%08" PRIx32,
		addr, count, *buffer);

	/* No need to waste time on useless operations. */
	if (!count)
		return ERROR_OK;

	/* We do not know where we come from. */
	arc_jtag_enque_reset_transaction(jtag_info);

	/* We want to write to memory. */
	arc_jtag_enque_set_transaction(jtag_info, ARC_JTAG_WRITE_TO_MEMORY, TAP_DRPAUSE);

	/* Set target memory address of the first word. */
	arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_ADDRESS_REG);
	arc_jtag_enque_write_dr(jtag_info, addr, TAP_DRPAUSE);

	/* Start sending words. Address is auto-incremented on 4bytes by HW. */
	arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_DATA_REG);

	uint32_t i;
	for (i = 0; i < count; i++)
		arc_jtag_enque_write_dr(jtag_info, *(buffer + i), TAP_IDLE);

	return jtag_execute_queue();
}

/**
 * Read a sequence of 4-byte words from target memory.
 *
 * We can read only 4byte words via JTAG.
 *
 * This function read directly from the memory, so it can read invalid data if
 * data cache hasn't been flushed before hand. It is responsibility of upper
 * level to resolve this.
 *
 * @param jtag_info
 * @param addr		Address of first word to read from.
 * @param count		Amount of words to read.
 * @param buffer	Array of words to read into.
 * @param slow_memory	Whether this is a slow memory (DDR) or fast (CCM).
 */
int arc_jtag_read_memory(struct arc_jtag *jtag_info, uint32_t addr,
	uint32_t count, uint32_t *buffer, bool slow_memory)
{
	uint8_t *data_buf;
	uint32_t i;
	int retval = ERROR_OK;


	assert(jtag_info);
	assert(jtag_info->tap);

	LOG_DEBUG("Reading memory: addr=0x%" PRIx32 ";count=%" PRIu32 ";slow=%c",
		addr, count, slow_memory ? 'Y' : 'N');

	if (!count)
		return ERROR_OK;

	data_buf = calloc(sizeof(uint8_t), count * 4);
	arc_jtag_enque_reset_transaction(jtag_info);

	/* We are reading from memory. */
	arc_jtag_enque_set_transaction(jtag_info, ARC_JTAG_READ_FROM_MEMORY, TAP_DRPAUSE);

	/* Read data */
	for (i = 0; i < count; i++) {
		/* When several words are read at consequent addresses we can
		 * rely on ARC JTAG auto-incrementing address. That means that
		 * address can be set only once, for a first word. However it
		 * has been noted that at least in some cases when reading from
		 * DDR, JTAG returns 0 instead of a real value. To workaround
		 * this issue we need to do totally non-required address
		 * writes, which however resolve a problem by introducing
		 * delay. See STAR 9000832538... */
		if (slow_memory || i == 0) {
		    /* Set address */
		    arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_ADDRESS_REG);
		    arc_jtag_enque_write_dr(jtag_info, addr + i * 4, TAP_IDLE);

		    arc_jtag_enque_write_ir(jtag_info, ARC_JTAG_DATA_REG);
		}
		arc_jtag_enque_read_dr(jtag_info, data_buf + i * 4, TAP_IDLE);
	}
	retval = jtag_execute_queue();
	if (retval != ERROR_OK) {
		LOG_ERROR("Failed to execute jtag queue: %d", retval);
		retval = ERROR_FAIL;
		goto exit;
	}

	/* Convert byte-buffers to host presentation. */
	for (i = 0; i < count; i++)
		buffer[i] = buf_get_u32(data_buf + 4*i, 0, 32);

exit:
	free(data_buf);

	return retval;
}