jtag/drivers/kitprog: Enable LOG_DEBUG_IO
[fw/openocd] / src / jtag / drivers / ftdi.c
index 81b27c26f1bd27ff62e8c2453f7929d068ea084a..32876bac5905bf5443995cf49d1c52fccebb6cca 100644 (file)
@@ -13,9 +13,7 @@
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
-*   along with this program; if not, write to the                         *
-*   Free Software Foundation, Inc.,                                       *
-*   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
+*   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/
 
 /**
@@ -72,6 +70,7 @@
 
 /* project specific includes */
 #include <jtag/interface.h>
+#include <jtag/swd.h>
 #include <transport/transport.h>
 #include <helper/time_support.h>
 
 #include "mpsse.h"
 
 #define JTAG_MODE (LSB_FIRST | POS_EDGE_IN | NEG_EDGE_OUT)
+#define JTAG_MODE_ALT (LSB_FIRST | NEG_EDGE_IN | NEG_EDGE_OUT)
+#define SWD_MODE (LSB_FIRST | POS_EDGE_IN | NEG_EDGE_OUT)
 
 static char *ftdi_device_desc;
 static char *ftdi_serial;
+static char *ftdi_location;
 static uint8_t ftdi_channel;
+static uint8_t ftdi_jtag_mode = JTAG_MODE;
+
+static bool swd_mode;
 
 #define MAX_USB_IDS 8
 /* vid = pid = 0 marks the end of the list */
@@ -100,16 +105,33 @@ static struct mpsse_ctx *mpsse_ctx;
 struct signal {
        const char *name;
        uint16_t data_mask;
+       uint16_t input_mask;
        uint16_t oe_mask;
        bool invert_data;
+       bool invert_input;
        bool invert_oe;
        struct signal *next;
 };
 
 static struct signal *signals;
 
+/* FIXME: Where to store per-instance data? We need an SWD context. */
+static struct swd_cmd_queue_entry {
+       uint8_t cmd;
+       uint32_t *dst;
+       uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
+} *swd_cmd_queue;
+static size_t swd_cmd_queue_length;
+static size_t swd_cmd_queue_alloced;
+static int queued_retval;
+static int freq;
+
 static uint16_t output;
 static uint16_t direction;
+static uint16_t jtag_output_init;
+static uint16_t jtag_direction_init;
+
+static int ftdi_swd_switch_seq(enum swd_special_seq seq);
 
 static struct signal *find_signal_by_name(const char *name)
 {
@@ -174,18 +196,49 @@ static int ftdi_set_signal(const struct signal *s, char value)
                return ERROR_FAIL;
        }
 
+       uint16_t old_output = output;
+       uint16_t old_direction = direction;
+
        output = data ? output | s->data_mask : output & ~s->data_mask;
        if (s->oe_mask == s->data_mask)
                direction = oe ? direction | s->oe_mask : direction & ~s->oe_mask;
        else
                output = oe ? output | s->oe_mask : output & ~s->oe_mask;
 
-       mpsse_set_data_bits_low_byte(mpsse_ctx, output & 0xff, direction & 0xff);
-       mpsse_set_data_bits_high_byte(mpsse_ctx, output >> 8, direction >> 8);
+       if ((output & 0xff) != (old_output & 0xff) || (direction & 0xff) != (old_direction & 0xff))
+               mpsse_set_data_bits_low_byte(mpsse_ctx, output & 0xff, direction & 0xff);
+       if ((output >> 8 != old_output >> 8) || (direction >> 8 != old_direction >> 8))
+               mpsse_set_data_bits_high_byte(mpsse_ctx, output >> 8, direction >> 8);
 
        return ERROR_OK;
 }
 
+static int ftdi_get_signal(const struct signal *s, uint16_t * value_out)
+{
+       uint8_t data_low = 0;
+       uint8_t data_high = 0;
+
+       if (s->input_mask == 0) {
+               LOG_ERROR("interface doesn't provide signal '%s'", s->name);
+               return ERROR_FAIL;
+       }
+
+       if (s->input_mask & 0xff)
+               mpsse_read_data_bits_low_byte(mpsse_ctx, &data_low);
+       if (s->input_mask >> 8)
+               mpsse_read_data_bits_high_byte(mpsse_ctx, &data_high);
+
+       mpsse_flush(mpsse_ctx);
+
+       *value_out = (((uint16_t)data_high) << 8) | data_low;
+
+       if (s->invert_input)
+               *value_out = ~(*value_out);
+
+       *value_out &= s->input_mask;
+
+       return ERROR_OK;
+}
 
 /**
  * Function move_to_state
@@ -220,7 +273,7 @@ static void move_to_state(tap_state_t goal_state)
                0,
                tms_count,
                false,
-               JTAG_MODE);
+               ftdi_jtag_mode);
 }
 
 static int ftdi_speed(int speed)
@@ -233,6 +286,9 @@ static int ftdi_speed(int speed)
                return retval;
        }
 
+       if (!swd_mode && speed >= 10000000 && ftdi_jtag_mode != JTAG_MODE_ALT)
+               LOG_INFO("ftdi: if you experience problems at higher adapter clocks, try "
+                        "the command \"ftdi_tdo_sample_edge falling\"");
        return ERROR_OK;
 }
 
@@ -280,7 +336,7 @@ static void ftdi_execute_runtest(struct jtag_command *cmd)
        while (i > 0) {
                /* there are no state transitions in this code, so omit state tracking */
                unsigned this_len = i > 7 ? 7 : i;
-               mpsse_clock_tms_cs_out(mpsse_ctx, &zero, 0, this_len, false, JTAG_MODE);
+               mpsse_clock_tms_cs_out(mpsse_ctx, &zero, 0, this_len, false, ftdi_jtag_mode);
                i -= this_len;
        }
 
@@ -320,7 +376,7 @@ static void ftdi_execute_tms(struct jtag_command *cmd)
                0,
                cmd->cmd.tms->num_bits,
                false,
-               JTAG_MODE);
+               ftdi_jtag_mode);
 }
 
 static void ftdi_execute_pathmove(struct jtag_command *cmd)
@@ -367,7 +423,7 @@ static void ftdi_execute_pathmove(struct jtag_command *cmd)
                                        0,
                                        bit_count,
                                        false,
-                                       JTAG_MODE);
+                                       ftdi_jtag_mode);
                        bit_count = 0;
                }
        }
@@ -422,7 +478,7 @@ static void ftdi_execute_scan(struct jtag_command *cmd)
                                field->in_value,
                                0,
                                field->num_bits - 1,
-                               JTAG_MODE);
+                               ftdi_jtag_mode);
                        uint8_t last_bit = 0;
                        if (field->out_value)
                                bit_copy(&last_bit, 0, field->out_value, field->num_bits - 1, 1);
@@ -434,14 +490,14 @@ static void ftdi_execute_scan(struct jtag_command *cmd)
                                        field->num_bits - 1,
                                        1,
                                        last_bit,
-                                       JTAG_MODE);
+                                       ftdi_jtag_mode);
                        tap_set_state(tap_state_transition(tap_get_state(), 1));
                        mpsse_clock_tms_cs_out(mpsse_ctx,
                                        &tms_bits,
                                        1,
                                        1,
                                        last_bit,
-                                       JTAG_MODE);
+                                       ftdi_jtag_mode);
                        tap_set_state(tap_state_transition(tap_get_state(), 0));
                } else
                        mpsse_clock_data(mpsse_ctx,
@@ -450,7 +506,7 @@ static void ftdi_execute_scan(struct jtag_command *cmd)
                                field->in_value,
                                0,
                                field->num_bits,
-                               JTAG_MODE);
+                               ftdi_jtag_mode);
        }
 
        if (tap_get_state() != tap_get_end_state())
@@ -477,7 +533,8 @@ static void ftdi_execute_reset(struct jtag_command *cmd)
                        ftdi_set_signal(trst, '0');
                else
                        LOG_ERROR("Can't assert TRST: nTRST signal is not defined");
-       } else if (trst && cmd->cmd.reset->trst == 0) {
+       } else if (trst && jtag_get_reset_config() & RESET_HAS_TRST &&
+                       cmd->cmd.reset->trst == 0) {
                if (jtag_get_reset_config() & RESET_TRST_OPEN_DRAIN)
                        ftdi_set_signal(trst, 'z');
                else
@@ -490,7 +547,8 @@ static void ftdi_execute_reset(struct jtag_command *cmd)
                        ftdi_set_signal(srst, '0');
                else
                        LOG_ERROR("Can't assert SRST: nSRST signal is not defined");
-       } else if (srst && cmd->cmd.reset->srst == 0) {
+       } else if (srst && jtag_get_reset_config() & RESET_HAS_SRST &&
+                       cmd->cmd.reset->srst == 0) {
                if (jtag_get_reset_config() & RESET_SRST_PUSH_PULL)
                        ftdi_set_signal(srst, '1');
                else
@@ -527,7 +585,7 @@ static void ftdi_execute_stableclocks(struct jtag_command *cmd)
        while (num_cycles > 0) {
                /* there are no state transitions in this code, so omit state tracking */
                unsigned this_len = num_cycles > 7 ? 7 : num_cycles;
-               mpsse_clock_tms_cs_out(mpsse_ctx, &tms, 0, this_len, false, JTAG_MODE);
+               mpsse_clock_tms_cs_out(mpsse_ctx, &tms, 0, this_len, false, ftdi_jtag_mode);
                num_cycles -= this_len;
        }
 
@@ -600,7 +658,7 @@ static int ftdi_initialize(void)
 
        for (int i = 0; ftdi_vid[i] || ftdi_pid[i]; i++) {
                mpsse_ctx = mpsse_open(&ftdi_vid[i], &ftdi_pid[i], ftdi_device_desc,
-                               ftdi_serial, ftdi_channel);
+                               ftdi_serial, ftdi_location, ftdi_channel);
                if (mpsse_ctx)
                        break;
        }
@@ -608,11 +666,27 @@ static int ftdi_initialize(void)
        if (!mpsse_ctx)
                return ERROR_JTAG_INIT_FAILED;
 
+       output = jtag_output_init;
+       direction = jtag_direction_init;
+
+       if (swd_mode) {
+               struct signal *sig = find_signal_by_name("SWD_EN");
+               if (!sig) {
+                       LOG_ERROR("SWD mode is active but SWD_EN signal is not defined");
+                       return ERROR_JTAG_INIT_FAILED;
+               }
+               /* A dummy SWD_EN would have zero mask */
+               if (sig->data_mask)
+                       ftdi_set_signal(sig, '1');
+       }
+
        mpsse_set_data_bits_low_byte(mpsse_ctx, output & 0xff, direction & 0xff);
        mpsse_set_data_bits_high_byte(mpsse_ctx, output >> 8, direction >> 8);
 
        mpsse_loopback_config(mpsse_ctx, false);
 
+       freq = mpsse_set_frequency(mpsse_ctx, jtag_get_speed_khz() * 1000);
+
        return mpsse_flush(mpsse_ctx);
 }
 
@@ -620,6 +694,8 @@ static int ftdi_quit(void)
 {
        mpsse_close(mpsse_ctx);
 
+       free(swd_cmd_queue);
+
        return ERROR_OK;
 }
 
@@ -649,6 +725,21 @@ COMMAND_HANDLER(ftdi_handle_serial_command)
        return ERROR_OK;
 }
 
+#ifdef HAVE_LIBUSB_GET_PORT_NUMBERS
+COMMAND_HANDLER(ftdi_handle_location_command)
+{
+       if (CMD_ARGC == 1) {
+               if (ftdi_location)
+                       free(ftdi_location);
+               ftdi_location = strdup(CMD_ARGV[0]);
+       } else {
+               return ERROR_COMMAND_SYNTAX_ERROR;
+       }
+
+       return ERROR_OK;
+}
+#endif
+
 COMMAND_HANDLER(ftdi_handle_channel_command)
 {
        if (CMD_ARGC == 1)
@@ -664,8 +755,8 @@ COMMAND_HANDLER(ftdi_handle_layout_init_command)
        if (CMD_ARGC != 2)
                return ERROR_COMMAND_SYNTAX_ERROR;
 
-       COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], output);
-       COMMAND_PARSE_NUMBER(u16, CMD_ARGV[1], direction);
+       COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], jtag_output_init);
+       COMMAND_PARSE_NUMBER(u16, CMD_ARGV[1], jtag_direction_init);
 
        return ERROR_OK;
 }
@@ -677,6 +768,8 @@ COMMAND_HANDLER(ftdi_handle_layout_signal_command)
 
        bool invert_data = false;
        uint16_t data_mask = 0;
+       bool invert_input = false;
+       uint16_t input_mask = 0;
        bool invert_oe = false;
        uint16_t oe_mask = 0;
        for (unsigned i = 1; i < CMD_ARGC; i += 2) {
@@ -686,12 +779,35 @@ COMMAND_HANDLER(ftdi_handle_layout_signal_command)
                } else if (strcmp("-ndata", CMD_ARGV[i]) == 0) {
                        invert_data = true;
                        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[i + 1], data_mask);
+               } else if (strcmp("-input", CMD_ARGV[i]) == 0) {
+                       invert_input = false;
+                       COMMAND_PARSE_NUMBER(u16, CMD_ARGV[i + 1], input_mask);
+               } else if (strcmp("-ninput", CMD_ARGV[i]) == 0) {
+                       invert_input = true;
+                       COMMAND_PARSE_NUMBER(u16, CMD_ARGV[i + 1], input_mask);
                } else if (strcmp("-oe", CMD_ARGV[i]) == 0) {
                        invert_oe = false;
                        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[i + 1], oe_mask);
                } else if (strcmp("-noe", CMD_ARGV[i]) == 0) {
                        invert_oe = true;
                        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[i + 1], oe_mask);
+               } else if (!strcmp("-alias", CMD_ARGV[i]) ||
+                          !strcmp("-nalias", CMD_ARGV[i])) {
+                       if (!strcmp("-nalias", CMD_ARGV[i])) {
+                               invert_data = true;
+                               invert_input = true;
+                       }
+                       struct signal *sig = find_signal_by_name(CMD_ARGV[i + 1]);
+                       if (!sig) {
+                               LOG_ERROR("signal %s is not defined", CMD_ARGV[i + 1]);
+                               return ERROR_FAIL;
+                       }
+                       data_mask = sig->data_mask;
+                       input_mask = sig->input_mask;
+                       oe_mask = sig->oe_mask;
+                       invert_input ^= sig->invert_input;
+                       invert_oe = sig->invert_oe;
+                       invert_data ^= sig->invert_data;
                } else {
                        LOG_ERROR("unknown option '%s'", CMD_ARGV[i]);
                        return ERROR_COMMAND_SYNTAX_ERROR;
@@ -709,6 +825,8 @@ COMMAND_HANDLER(ftdi_handle_layout_signal_command)
 
        sig->invert_data = invert_data;
        sig->data_mask = data_mask;
+       sig->invert_input = invert_input;
+       sig->input_mask = input_mask;
        sig->invert_oe = invert_oe;
        sig->oe_mask = oe_mask;
 
@@ -737,6 +855,7 @@ COMMAND_HANDLER(ftdi_handle_set_signal_command)
                        ftdi_set_signal(sig, *CMD_ARGV[1]);
                        break;
                }
+               /* fallthrough */
        default:
                LOG_ERROR("unknown signal level '%s', use 0, 1 or z", CMD_ARGV[1]);
                return ERROR_COMMAND_SYNTAX_ERROR;
@@ -745,6 +864,28 @@ COMMAND_HANDLER(ftdi_handle_set_signal_command)
        return mpsse_flush(mpsse_ctx);
 }
 
+COMMAND_HANDLER(ftdi_handle_get_signal_command)
+{
+       if (CMD_ARGC < 1)
+               return ERROR_COMMAND_SYNTAX_ERROR;
+
+       struct signal *sig;
+       uint16_t sig_data = 0;
+       sig = find_signal_by_name(CMD_ARGV[0]);
+       if (!sig) {
+               LOG_ERROR("interface configuration doesn't define signal '%s'", CMD_ARGV[0]);
+               return ERROR_FAIL;
+       }
+
+       int ret = ftdi_get_signal(sig, &sig_data);
+       if (ret != ERROR_OK)
+               return ret;
+
+       LOG_USER("Signal %s = %#06x", sig->name, sig_data);
+
+       return ERROR_OK;
+}
+
 COMMAND_HANDLER(ftdi_handle_vid_pid_command)
 {
        if (CMD_ARGC > MAX_USB_IDS * 2) {
@@ -775,6 +916,29 @@ COMMAND_HANDLER(ftdi_handle_vid_pid_command)
        return ERROR_OK;
 }
 
+COMMAND_HANDLER(ftdi_handle_tdo_sample_edge_command)
+{
+       Jim_Nvp *n;
+       static const Jim_Nvp nvp_ftdi_jtag_modes[] = {
+               { .name = "rising", .value = JTAG_MODE },
+               { .name = "falling", .value = JTAG_MODE_ALT },
+               { .name = NULL, .value = -1 },
+       };
+
+       if (CMD_ARGC > 0) {
+               n = Jim_Nvp_name2value_simple(nvp_ftdi_jtag_modes, CMD_ARGV[0]);
+               if (n->name == NULL)
+                       return ERROR_COMMAND_SYNTAX_ERROR;
+               ftdi_jtag_mode = n->value;
+
+       }
+
+       n = Jim_Nvp_value2name_simple(nvp_ftdi_jtag_modes, ftdi_jtag_mode);
+       command_print(CMD_CTX, "ftdi samples TDO on %s edge of TCK", n->name);
+
+       return ERROR_OK;
+}
+
 static const struct command_registration ftdi_command_handlers[] = {
        {
                .name = "ftdi_device_desc",
@@ -790,6 +954,15 @@ static const struct command_registration ftdi_command_handlers[] = {
                .help = "set the serial number of the FTDI device",
                .usage = "serial_string",
        },
+#ifdef HAVE_LIBUSB_GET_PORT_NUMBERS
+       {
+               .name = "ftdi_location",
+               .handler = &ftdi_handle_location_command,
+               .mode = COMMAND_CONFIG,
+               .help = "set the USB bus location of the FTDI device",
+               .usage = "<bus>:port[,port]...",
+       },
+#endif
        {
                .name = "ftdi_channel",
                .handler = &ftdi_handle_channel_command,
@@ -811,7 +984,7 @@ static const struct command_registration ftdi_command_handlers[] = {
                .mode = COMMAND_ANY,
                .help = "define a signal controlled by one or more FTDI GPIO as data "
                        "and/or output enable",
-               .usage = "name [-data mask|-ndata mask] [-oe mask|-noe mask]",
+               .usage = "name [-data mask|-ndata mask] [-oe mask|-noe mask] [-alias|-nalias name]",
        },
        {
                .name = "ftdi_set_signal",
@@ -820,6 +993,13 @@ static const struct command_registration ftdi_command_handlers[] = {
                .help = "control a layout-specific signal",
                .usage = "name (1|0|z)",
        },
+       {
+               .name = "ftdi_get_signal",
+               .handler = &ftdi_handle_get_signal_command,
+               .mode = COMMAND_EXEC,
+               .help = "read the value of a layout-specific signal",
+               .usage = "name",
+       },
        {
                .name = "ftdi_vid_pid",
                .handler = &ftdi_handle_vid_pid_command,
@@ -827,14 +1007,255 @@ static const struct command_registration ftdi_command_handlers[] = {
                .help = "the vendor ID and product ID of the FTDI device",
                .usage = "(vid pid)* ",
        },
+       {
+               .name = "ftdi_tdo_sample_edge",
+               .handler = &ftdi_handle_tdo_sample_edge_command,
+               .mode = COMMAND_ANY,
+               .help = "set which TCK clock edge is used for sampling TDO "
+                       "- default is rising-edge (Setting to falling-edge may "
+                       "allow signalling speed increase)",
+               .usage = "(rising|falling)",
+       },
        COMMAND_REGISTRATION_DONE
 };
 
+static int create_default_signal(const char *name, uint16_t data_mask)
+{
+       struct signal *sig = create_signal(name);
+       if (!sig) {
+               LOG_ERROR("failed to create signal %s", name);
+               return ERROR_FAIL;
+       }
+       sig->invert_data = false;
+       sig->data_mask = data_mask;
+       sig->invert_oe = false;
+       sig->oe_mask = 0;
+
+       return ERROR_OK;
+}
+
+static int create_signals(void)
+{
+       if (create_default_signal("TCK", 0x01) != ERROR_OK)
+               return ERROR_FAIL;
+       if (create_default_signal("TDI", 0x02) != ERROR_OK)
+               return ERROR_FAIL;
+       if (create_default_signal("TDO", 0x04) != ERROR_OK)
+               return ERROR_FAIL;
+       if (create_default_signal("TMS", 0x08) != ERROR_OK)
+               return ERROR_FAIL;
+       return ERROR_OK;
+}
+
+static int ftdi_swd_init(void)
+{
+       LOG_INFO("FTDI SWD mode enabled");
+       swd_mode = true;
+
+       if (create_signals() != ERROR_OK)
+               return ERROR_FAIL;
+
+       swd_cmd_queue_alloced = 10;
+       swd_cmd_queue = malloc(swd_cmd_queue_alloced * sizeof(*swd_cmd_queue));
+
+       return swd_cmd_queue != NULL ? ERROR_OK : ERROR_FAIL;
+}
+
+static void ftdi_swd_swdio_en(bool enable)
+{
+       struct signal *oe = find_signal_by_name("SWDIO_OE");
+       if (oe)
+               ftdi_set_signal(oe, enable ? '1' : '0');
+}
+
+/**
+ * Flush the MPSSE queue and process the SWD transaction queue
+ * @param dap
+ * @return
+ */
+static int ftdi_swd_run_queue(void)
+{
+       LOG_DEBUG_IO("Executing %zu queued transactions", swd_cmd_queue_length);
+       int retval;
+       struct signal *led = find_signal_by_name("LED");
+
+       if (queued_retval != ERROR_OK) {
+               LOG_DEBUG_IO("Skipping due to previous errors: %d", queued_retval);
+               goto skip;
+       }
+
+       /* A transaction must be followed by another transaction or at least 8 idle cycles to
+        * ensure that data is clocked through the AP. */
+       mpsse_clock_data_out(mpsse_ctx, NULL, 0, 8, SWD_MODE);
+
+       /* Terminate the "blink", if the current layout has that feature */
+       if (led)
+               ftdi_set_signal(led, '0');
+
+       queued_retval = mpsse_flush(mpsse_ctx);
+       if (queued_retval != ERROR_OK) {
+               LOG_ERROR("MPSSE failed");
+               goto skip;
+       }
+
+       for (size_t i = 0; i < swd_cmd_queue_length; i++) {
+               int ack = buf_get_u32(swd_cmd_queue[i].trn_ack_data_parity_trn, 1, 3);
+
+               LOG_DEBUG_IO("%s %s %s reg %X = %08"PRIx32,
+                               ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
+                               swd_cmd_queue[i].cmd & SWD_CMD_APnDP ? "AP" : "DP",
+                               swd_cmd_queue[i].cmd & SWD_CMD_RnW ? "read" : "write",
+                               (swd_cmd_queue[i].cmd & SWD_CMD_A32) >> 1,
+                               buf_get_u32(swd_cmd_queue[i].trn_ack_data_parity_trn,
+                                               1 + 3 + (swd_cmd_queue[i].cmd & SWD_CMD_RnW ? 0 : 1), 32));
+
+               if (ack != SWD_ACK_OK) {
+                       queued_retval = ack == SWD_ACK_WAIT ? ERROR_WAIT : ERROR_FAIL;
+                       goto skip;
+
+               } else if (swd_cmd_queue[i].cmd & SWD_CMD_RnW) {
+                       uint32_t data = buf_get_u32(swd_cmd_queue[i].trn_ack_data_parity_trn, 1 + 3, 32);
+                       int parity = buf_get_u32(swd_cmd_queue[i].trn_ack_data_parity_trn, 1 + 3 + 32, 1);
+
+                       if (parity != parity_u32(data)) {
+                               LOG_ERROR("SWD Read data parity mismatch");
+                               queued_retval = ERROR_FAIL;
+                               goto skip;
+                       }
+
+                       if (swd_cmd_queue[i].dst != NULL)
+                               *swd_cmd_queue[i].dst = data;
+               }
+       }
+
+skip:
+       swd_cmd_queue_length = 0;
+       retval = queued_retval;
+       queued_retval = ERROR_OK;
+
+       /* Queue a new "blink" */
+       if (led && retval == ERROR_OK)
+               ftdi_set_signal(led, '1');
+
+       return retval;
+}
+
+static void ftdi_swd_queue_cmd(uint8_t cmd, uint32_t *dst, uint32_t data, uint32_t ap_delay_clk)
+{
+       if (swd_cmd_queue_length >= swd_cmd_queue_alloced) {
+               /* Not enough room in the queue. Run the queue and increase its size for next time.
+                * Note that it's not possible to avoid running the queue here, because mpsse contains
+                * pointers into the queue which may be invalid after the realloc. */
+               queued_retval = ftdi_swd_run_queue();
+               struct swd_cmd_queue_entry *q = realloc(swd_cmd_queue, swd_cmd_queue_alloced * 2 * sizeof(*swd_cmd_queue));
+               if (q != NULL) {
+                       swd_cmd_queue = q;
+                       swd_cmd_queue_alloced *= 2;
+                       LOG_DEBUG("Increased SWD command queue to %zu elements", swd_cmd_queue_alloced);
+               }
+       }
+
+       if (queued_retval != ERROR_OK)
+               return;
+
+       size_t i = swd_cmd_queue_length++;
+       swd_cmd_queue[i].cmd = cmd | SWD_CMD_START | SWD_CMD_PARK;
+
+       mpsse_clock_data_out(mpsse_ctx, &swd_cmd_queue[i].cmd, 0, 8, SWD_MODE);
+
+       if (swd_cmd_queue[i].cmd & SWD_CMD_RnW) {
+               /* Queue a read transaction */
+               swd_cmd_queue[i].dst = dst;
+
+               ftdi_swd_swdio_en(false);
+               mpsse_clock_data_in(mpsse_ctx, swd_cmd_queue[i].trn_ack_data_parity_trn,
+                               0, 1 + 3 + 32 + 1 + 1, SWD_MODE);
+               ftdi_swd_swdio_en(true);
+       } else {
+               /* Queue a write transaction */
+               ftdi_swd_swdio_en(false);
+
+               mpsse_clock_data_in(mpsse_ctx, swd_cmd_queue[i].trn_ack_data_parity_trn,
+                               0, 1 + 3 + 1, SWD_MODE);
+
+               ftdi_swd_swdio_en(true);
+
+               buf_set_u32(swd_cmd_queue[i].trn_ack_data_parity_trn, 1 + 3 + 1, 32, data);
+               buf_set_u32(swd_cmd_queue[i].trn_ack_data_parity_trn, 1 + 3 + 1 + 32, 1, parity_u32(data));
+
+               mpsse_clock_data_out(mpsse_ctx, swd_cmd_queue[i].trn_ack_data_parity_trn,
+                               1 + 3 + 1, 32 + 1, SWD_MODE);
+       }
+
+       /* Insert idle cycles after AP accesses to avoid WAIT */
+       if (cmd & SWD_CMD_APnDP)
+               mpsse_clock_data_out(mpsse_ctx, NULL, 0, ap_delay_clk, SWD_MODE);
+
+}
+
+static void ftdi_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay_clk)
+{
+       assert(cmd & SWD_CMD_RnW);
+       ftdi_swd_queue_cmd(cmd, value, 0, ap_delay_clk);
+}
+
+static void ftdi_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk)
+{
+       assert(!(cmd & SWD_CMD_RnW));
+       ftdi_swd_queue_cmd(cmd, NULL, value, ap_delay_clk);
+}
+
+static int_least32_t ftdi_swd_frequency(int_least32_t hz)
+{
+       if (hz > 0)
+               freq = mpsse_set_frequency(mpsse_ctx, hz);
+
+       return freq;
+}
+
+static int ftdi_swd_switch_seq(enum swd_special_seq seq)
+{
+       switch (seq) {
+       case LINE_RESET:
+               LOG_DEBUG("SWD line reset");
+               ftdi_swd_swdio_en(true);
+               mpsse_clock_data_out(mpsse_ctx, swd_seq_line_reset, 0, swd_seq_line_reset_len, SWD_MODE);
+               break;
+       case JTAG_TO_SWD:
+               LOG_DEBUG("JTAG-to-SWD");
+               ftdi_swd_swdio_en(true);
+               mpsse_clock_data_out(mpsse_ctx, swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len, SWD_MODE);
+               break;
+       case SWD_TO_JTAG:
+               LOG_DEBUG("SWD-to-JTAG");
+               ftdi_swd_swdio_en(true);
+               mpsse_clock_data_out(mpsse_ctx, swd_seq_swd_to_jtag, 0, swd_seq_swd_to_jtag_len, SWD_MODE);
+               break;
+       default:
+               LOG_ERROR("Sequence %d not supported", seq);
+               return ERROR_FAIL;
+       }
+
+       return ERROR_OK;
+}
+
+static const struct swd_driver ftdi_swd = {
+       .init = ftdi_swd_init,
+       .frequency = ftdi_swd_frequency,
+       .switch_seq = ftdi_swd_switch_seq,
+       .read_reg = ftdi_swd_read_reg,
+       .write_reg = ftdi_swd_write_reg,
+       .run = ftdi_swd_run_queue,
+};
+
+static const char * const ftdi_transports[] = { "jtag", "swd", NULL };
+
 struct jtag_interface ftdi_interface = {
        .name = "ftdi",
        .supported = DEBUG_CAP_TMS_SEQ,
        .commands = ftdi_command_handlers,
-       .transports = jtag_only,
+       .transports = ftdi_transports,
+       .swd = &ftdi_swd,
 
        .init = ftdi_initialize,
        .quit = ftdi_quit,