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// SPDX-License-Identifier: GPL-2.0-or-later
/***************************************************************************
* Copyright (C) 2018 by Square, Inc. *
* Steven Stallion <stallion@squareup.com> *
* James Zhao <hjz@squareup.com> *
***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <helper/binarybuffer.h>
#include <helper/log.h>
#include <helper/types.h>
#include <jtag/jtag.h>
#include <jtag/commands.h>
#include <jtag/interface.h>
#include "esirisc_jtag.h"
static void esirisc_jtag_set_instr(struct esirisc_jtag *jtag_info, uint32_t new_instr)
{
struct jtag_tap *tap = jtag_info->tap;
if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) != new_instr) {
struct scan_field field;
uint8_t t[4] = { 0 };
field.num_bits = tap->ir_length;
field.out_value = t;
buf_set_u32(t, 0, field.num_bits, new_instr);
field.in_value = NULL;
jtag_add_ir_scan(tap, &field, TAP_IDLE);
}
}
/*
* The data register is latched every 8 bits while in the Shift-DR state
* (Update-DR is not supported). This necessitates prepending padding
* bits to ensure data is aligned when multiple TAPs are present.
*/
static int esirisc_jtag_get_padding(void)
{
int padding = 0;
int bypass_devices = 0;
for (struct jtag_tap *tap = jtag_tap_next_enabled(NULL); tap;
tap = jtag_tap_next_enabled(tap))
if (tap->bypass)
bypass_devices++;
int num_bits = bypass_devices % 8;
if (num_bits > 0)
padding = 8 - num_bits;
return padding;
}
static int esirisc_jtag_count_bits(unsigned int num_fields,
struct scan_field *fields)
{
int bit_count = 0;
for (unsigned int i = 0; i < num_fields; ++i)
bit_count += fields[i].num_bits;
return bit_count;
}
/*
* Data received from the target will be byte-stuffed if it contains
* either the pad byte (0xAA) or stuffing marker (0x55). Buffers should
* be sized twice the expected length to account for stuffing overhead.
*/
static void esirisc_jtag_unstuff(uint8_t *data, size_t len)
{
uint8_t *r, *w;
uint8_t *end;
r = w = data;
end = data + len;
while (r < end) {
if (*r == STUFF_MARKER) {
r++; /* skip stuffing marker */
assert(r < end);
*w++ = *r++ ^ STUFF_MARKER;
} else
*w++ = *r++;
}
}
/*
* The eSi-Debug protocol defines a byte-oriented command/response
* channel that operates over serial or JTAG. While not strictly
* required, separate DR scans are used for sending and receiving data.
* This allows the TAP to recover gracefully if the byte stream is
* corrupted at the expense of sending additional padding bits.
*/
static int esirisc_jtag_send(struct esirisc_jtag *jtag_info, uint8_t command,
int num_out_fields, struct scan_field *out_fields)
{
int num_fields = 2 + num_out_fields;
struct scan_field *fields = cmd_queue_alloc(num_fields * sizeof(struct scan_field));
esirisc_jtag_set_instr(jtag_info, INSTR_DEBUG);
fields[0].num_bits = esirisc_jtag_get_padding();
fields[0].out_value = NULL;
fields[0].in_value = NULL;
fields[1].num_bits = 8;
fields[1].out_value = &command;
fields[1].in_value = NULL;
/* append command data */
for (int i = 0; i < num_out_fields; ++i)
jtag_scan_field_clone(&fields[2+i], &out_fields[i]);
jtag_add_dr_scan(jtag_info->tap, num_fields, fields, TAP_IDLE);
return jtag_execute_queue();
}
static int esirisc_jtag_recv(struct esirisc_jtag *jtag_info,
int num_in_fields, struct scan_field *in_fields)
{
int num_in_bits = esirisc_jtag_count_bits(num_in_fields, in_fields);
int num_in_bytes = DIV_ROUND_UP(num_in_bits, 8);
struct scan_field fields[3];
/* prevent zero-size variable length array */
int r_size = num_in_bytes ? num_in_bytes * 2 : 1;
uint8_t r[r_size];
esirisc_jtag_set_instr(jtag_info, INSTR_DEBUG);
fields[0].num_bits = esirisc_jtag_get_padding() + 1;
fields[0].out_value = NULL;
fields[0].in_value = NULL;
fields[1].num_bits = 8;
fields[1].out_value = NULL;
fields[1].in_value = &jtag_info->status;
fields[2].num_bits = num_in_bits * 2;
fields[2].out_value = NULL;
fields[2].in_value = r;
jtag_add_dr_scan(jtag_info->tap, ARRAY_SIZE(fields), fields, TAP_IDLE);
int retval = jtag_execute_queue();
if (retval != ERROR_OK)
return retval;
/* unstuff response data and write back to caller */
if (num_in_fields > 0) {
esirisc_jtag_unstuff(r, ARRAY_SIZE(r));
int bit_count = 0;
for (int i = 0; i < num_in_fields; ++i) {
buf_set_buf(r, bit_count, in_fields[i].in_value, 0, in_fields[i].num_bits);
bit_count += in_fields[i].num_bits;
}
}
return ERROR_OK;
}
static int esirisc_jtag_check_status(struct esirisc_jtag *jtag_info)
{
uint8_t eid = esirisc_jtag_get_eid(jtag_info);
if (eid != EID_NONE) {
LOG_ERROR("esirisc_jtag: bad status: 0x%02" PRIx8 " (DA: %" PRId32 ", "
"S: %" PRId32 ", EID: 0x%02" PRIx8 ")",
jtag_info->status, esirisc_jtag_is_debug_active(jtag_info),
esirisc_jtag_is_stopped(jtag_info), eid);
return ERROR_FAIL;
}
return ERROR_OK;
}
static int esirisc_jtag_send_and_recv(struct esirisc_jtag *jtag_info, uint8_t command,
int num_out_fields, struct scan_field *out_fields,
int num_in_fields, struct scan_field *in_fields)
{
int retval;
jtag_info->status = 0; /* clear status */
retval = esirisc_jtag_send(jtag_info, command, num_out_fields, out_fields);
if (retval != ERROR_OK) {
LOG_ERROR("esirisc_jtag: send failed (command: 0x%02" PRIx8 ")", command);
return ERROR_FAIL;
}
retval = esirisc_jtag_recv(jtag_info, num_in_fields, in_fields);
if (retval != ERROR_OK) {
LOG_ERROR("esirisc_jtag: recv failed (command: 0x%02" PRIx8 ")", command);
return ERROR_FAIL;
}
return esirisc_jtag_check_status(jtag_info);
}
/*
* Status is automatically updated after each command completes;
* these functions make each field available to the caller.
*/
bool esirisc_jtag_is_debug_active(struct esirisc_jtag *jtag_info)
{
return !!(jtag_info->status & 1<<7); /* DA */
}
bool esirisc_jtag_is_stopped(struct esirisc_jtag *jtag_info)
{
return !!(jtag_info->status & 1<<6); /* S */
}
uint8_t esirisc_jtag_get_eid(struct esirisc_jtag *jtag_info)
{
return jtag_info->status & 0x3f; /* EID */
}
/*
* Most commands manipulate target data (eg. memory and registers); each
* command returns a status byte that indicates success. Commands must
* transmit multibyte values in big-endian order, however response
* values are in little-endian order. Target endianness does not have an
* effect on this ordering.
*/
int esirisc_jtag_read_byte(struct esirisc_jtag *jtag_info, uint32_t address, uint8_t *data)
{
struct scan_field out_fields[1];
uint8_t a[4];
out_fields[0].num_bits = 32;
out_fields[0].out_value = a;
h_u32_to_be(a, address);
out_fields[0].in_value = NULL;
struct scan_field in_fields[1];
uint8_t d[1];
in_fields[0].num_bits = 8;
in_fields[0].out_value = NULL;
in_fields[0].in_value = d;
int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_BYTE,
ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
if (retval != ERROR_OK)
return retval;
*data = *d;
LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx8, address, *data);
return ERROR_OK;
}
int esirisc_jtag_read_hword(struct esirisc_jtag *jtag_info, uint32_t address, uint16_t *data)
{
struct scan_field out_fields[1];
uint8_t a[4];
out_fields[0].num_bits = 32;
out_fields[0].out_value = a;
h_u32_to_be(a, address);
out_fields[0].in_value = NULL;
struct scan_field in_fields[1];
uint8_t d[2];
in_fields[0].num_bits = 16;
in_fields[0].out_value = NULL;
in_fields[0].in_value = d;
int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_HWORD,
ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
if (retval != ERROR_OK)
return retval;
*data = le_to_h_u16(d);
LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx16, address, *data);
return ERROR_OK;
}
int esirisc_jtag_read_word(struct esirisc_jtag *jtag_info, uint32_t address, uint32_t *data)
{
struct scan_field out_fields[1];
uint8_t a[4];
out_fields[0].num_bits = 32;
out_fields[0].out_value = a;
h_u32_to_be(a, address);
out_fields[0].in_value = NULL;
struct scan_field in_fields[1];
uint8_t d[4];
in_fields[0].num_bits = 32;
in_fields[0].out_value = NULL;
in_fields[0].in_value = d;
int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_WORD,
ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
if (retval != ERROR_OK)
return retval;
*data = le_to_h_u32(d);
LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx32, address, *data);
return ERROR_OK;
}
int esirisc_jtag_write_byte(struct esirisc_jtag *jtag_info, uint32_t address, uint8_t data)
{
struct scan_field out_fields[2];
uint8_t a[4];
LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx8, address, data);
out_fields[0].num_bits = 32;
out_fields[0].out_value = a;
h_u32_to_be(a, address);
out_fields[0].in_value = NULL;
out_fields[1].num_bits = 8;
out_fields[1].out_value = &data;
out_fields[1].in_value = NULL;
return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_BYTE,
ARRAY_SIZE(out_fields), out_fields, 0, NULL);
}
int esirisc_jtag_write_hword(struct esirisc_jtag *jtag_info, uint32_t address, uint16_t data)
{
struct scan_field out_fields[2];
uint8_t a[4], d[2];
LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx16, address, data);
out_fields[0].num_bits = 32;
out_fields[0].out_value = a;
h_u32_to_be(a, address);
out_fields[0].in_value = NULL;
out_fields[1].num_bits = 16;
out_fields[1].out_value = d;
h_u16_to_be(d, data);
out_fields[1].in_value = NULL;
return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_HWORD,
ARRAY_SIZE(out_fields), out_fields, 0, NULL);
}
int esirisc_jtag_write_word(struct esirisc_jtag *jtag_info, uint32_t address, uint32_t data)
{
struct scan_field out_fields[2];
uint8_t a[4], d[4];
LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx32, address, data);
out_fields[0].num_bits = 32;
out_fields[0].out_value = a;
h_u32_to_be(a, address);
out_fields[0].in_value = NULL;
out_fields[1].num_bits = 32;
out_fields[1].out_value = d;
h_u32_to_be(d, data);
out_fields[1].in_value = NULL;
return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_WORD,
ARRAY_SIZE(out_fields), out_fields, 0, NULL);
}
int esirisc_jtag_read_reg(struct esirisc_jtag *jtag_info, uint8_t reg, uint32_t *data)
{
struct scan_field out_fields[1];
out_fields[0].num_bits = 8;
out_fields[0].out_value = ®
out_fields[0].in_value = NULL;
struct scan_field in_fields[1];
uint8_t d[4];
in_fields[0].num_bits = 32;
in_fields[0].out_value = NULL;
in_fields[0].in_value = d;
int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_REG,
ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
if (retval != ERROR_OK)
return retval;
*data = le_to_h_u32(d);
LOG_DEBUG("register: 0x%" PRIx8 ", data: 0x%" PRIx32, reg, *data);
return ERROR_OK;
}
int esirisc_jtag_write_reg(struct esirisc_jtag *jtag_info, uint8_t reg, uint32_t data)
{
struct scan_field out_fields[2];
uint8_t d[4];
LOG_DEBUG("register: 0x%" PRIx8 ", data: 0x%" PRIx32, reg, data);
out_fields[0].num_bits = 8;
out_fields[0].out_value = ®
out_fields[0].in_value = NULL;
out_fields[1].num_bits = 32;
out_fields[1].out_value = d;
h_u32_to_be(d, data);
out_fields[1].in_value = NULL;
return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_REG,
ARRAY_SIZE(out_fields), out_fields, 0, NULL);
}
int esirisc_jtag_read_csr(struct esirisc_jtag *jtag_info, uint8_t bank, uint8_t csr, uint32_t *data)
{
struct scan_field out_fields[1];
uint8_t c[2];
out_fields[0].num_bits = 16;
out_fields[0].out_value = c;
h_u16_to_be(c, (csr << 5) | bank);
out_fields[0].in_value = NULL;
struct scan_field in_fields[1];
uint8_t d[4];
in_fields[0].num_bits = 32;
in_fields[0].out_value = NULL;
in_fields[0].in_value = d;
int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_CSR,
ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
if (retval != ERROR_OK)
return retval;
*data = le_to_h_u32(d);
LOG_DEBUG("bank: 0x%" PRIx8 ", csr: 0x%" PRIx8 ", data: 0x%" PRIx32, bank, csr, *data);
return ERROR_OK;
}
int esirisc_jtag_write_csr(struct esirisc_jtag *jtag_info, uint8_t bank, uint8_t csr, uint32_t data)
{
struct scan_field out_fields[2];
uint8_t c[2], d[4];
LOG_DEBUG("bank: 0x%" PRIx8 ", csr: 0x%" PRIx8 ", data: 0x%" PRIx32, bank, csr, data);
out_fields[0].num_bits = 16;
out_fields[0].out_value = c;
h_u16_to_be(c, (csr << 5) | bank);
out_fields[0].in_value = NULL;
out_fields[1].num_bits = 32;
out_fields[1].out_value = d;
h_u32_to_be(d, data);
out_fields[1].in_value = NULL;
return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_CSR,
ARRAY_SIZE(out_fields), out_fields, 0, NULL);
}
/*
* Control commands affect CPU operation; these commands send no data
* and return a status byte.
*/
static inline int esirisc_jtag_send_ctrl(struct esirisc_jtag *jtag_info, uint8_t command)
{
return esirisc_jtag_send_and_recv(jtag_info, command, 0, NULL, 0, NULL);
}
int esirisc_jtag_enable_debug(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_ENABLE_DEBUG);
}
int esirisc_jtag_disable_debug(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_DISABLE_DEBUG);
}
int esirisc_jtag_assert_reset(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_ASSERT_RESET);
}
int esirisc_jtag_deassert_reset(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_DEASSERT_RESET);
}
int esirisc_jtag_break(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_BREAK);
}
int esirisc_jtag_continue(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_CONTINUE);
}
int esirisc_jtag_flush_caches(struct esirisc_jtag *jtag_info)
{
return esirisc_jtag_send_ctrl(jtag_info, DEBUG_FLUSH_CACHES);
}
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