jlink: fix jlink regression introduced by ae8cdc commit
[fw/openocd] / src / jtag / drivers / jlink.c
index db211805243dfaf67a3e4ed82ca15e19a32d879d..30090582336029d8303f6f8bdba01763e032186f 100644 (file)
@@ -11,6 +11,9 @@
  *   Copyright (C) 2015 by Marc Schink                                     *
  *   openocd-dev@marcschink.de                                             *
  *                                                                         *
+ *   Copyright (C) 2015 by Paul Fertser                                    *
+ *   fercerpav@gmail.com                                                   *
+ *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
  *   the Free Software Foundation; either version 2 of the License, or     *
@@ -22,8 +25,7 @@
  *   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.,                                       *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  ***************************************************************************/
 
 #ifdef HAVE_CONFIG_H
@@ -48,9 +50,9 @@ static uint8_t caps[JAYLINK_DEV_EXT_CAPS_SIZE];
 
 static uint32_t serial_number;
 static bool use_serial_number;
-static uint8_t usb_address;
+static enum jaylink_usb_address usb_address;
 static bool use_usb_address;
-static uint8_t iface = JAYLINK_TIF_JTAG;
+static enum jaylink_target_interface iface = JAYLINK_TIF_JTAG;
 static bool trace_enabled;
 
 #define JLINK_MAX_SPEED                        12000
@@ -83,23 +85,34 @@ static struct device_config tmp_config;
 static void jlink_end_state(tap_state_t state);
 static void jlink_state_move(void);
 static void jlink_path_move(int num_states, tap_state_t *path);
+static void jlink_stableclocks(int num_cycles);
 static void jlink_runtest(int num_cycles);
-static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer,
-               int scan_size, struct scan_command *command);
 static void jlink_reset(int trst, int srst);
-static int jlink_swd_run_queue(struct adiv5_dap *dap);
-static void jlink_swd_queue_cmd(struct adiv5_dap *dap, uint8_t cmd,
-               uint32_t *dst, uint32_t data);
-static int jlink_swd_switch_seq(struct adiv5_dap *dap,
-               enum swd_special_seq seq);
+static int jlink_swd_run_queue(void);
+static void jlink_swd_queue_cmd(uint8_t cmd, uint32_t *dst, uint32_t data, uint32_t ap_delay_clk);
+static int jlink_swd_switch_seq(enum swd_special_seq seq);
 
 /* J-Link tap buffer functions */
 static void jlink_tap_init(void);
-static int jlink_tap_execute(void);
-static void jlink_tap_ensure_space(int scans, int bits);
-static void jlink_tap_append_step(int tms, int tdi);
-static void jlink_tap_append_scan(int length, uint8_t *buffer,
-               struct scan_command *command);
+static int jlink_flush(void);
+/**
+ * Queue data to go out and in, flushing the queue as many times as
+ * necessary.
+ *
+ * @param out A pointer to TDI data, if NULL, old stale data will be used.
+ * @param out_offset A bit offset for TDI data.
+ * @param tms_out A pointer to TMS data, if NULL, zeroes will be emitted.
+ * @param tms_offset A bit offset for TMS data.
+ * @param in A pointer to store TDO data to, if NULL the data will be discarded.
+ * @param in_offset A bit offset for TDO data.
+ * @param length Amount of bits to transfer out and in.
+ *
+ * @retval This function doesn't return any value.
+ */
+static void jlink_clock_data(const uint8_t *out, unsigned out_offset,
+                            const uint8_t *tms_out, unsigned tms_offset,
+                            uint8_t *in, unsigned in_offset,
+                            unsigned length);
 
 static enum tap_state jlink_last_state = TAP_RESET;
 static int queued_retval;
@@ -107,6 +120,12 @@ static int queued_retval;
 /***************************************************************************/
 /* External interface implementation */
 
+static void jlink_execute_stableclocks(struct jtag_command *cmd)
+{
+       DEBUG_JTAG_IO("stableclocks %i cycles", cmd->cmd.runtest->num_cycles);
+       jlink_stableclocks(cmd->cmd.runtest->num_cycles);
+}
+
 static void jlink_execute_runtest(struct jtag_command *cmd)
 {
        DEBUG_JTAG_IO("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles,
@@ -135,19 +154,95 @@ static void jlink_execute_pathmove(struct jtag_command *cmd)
 
 static void jlink_execute_scan(struct jtag_command *cmd)
 {
-       int scan_size;
-       enum scan_type type;
-       uint8_t *buffer;
+       DEBUG_JTAG_IO("%s type:%d", cmd->cmd.scan->ir_scan ? "IRSCAN" : "DRSCAN",
+               jtag_scan_type(cmd->cmd.scan));
+
+       /* Make sure there are no trailing fields with num_bits == 0, or the logic below will fail. */
+       while (cmd->cmd.scan->num_fields > 0
+                       && cmd->cmd.scan->fields[cmd->cmd.scan->num_fields - 1].num_bits == 0) {
+               cmd->cmd.scan->num_fields--;
+               LOG_DEBUG("discarding trailing empty field");
+       }
+
+       if (cmd->cmd.scan->num_fields == 0) {
+               LOG_DEBUG("empty scan, doing nothing");
+               return;
+       }
 
-       DEBUG_JTAG_IO("scan end in %s", tap_state_name(cmd->cmd.scan->end_state));
+       if (cmd->cmd.scan->ir_scan) {
+               if (tap_get_state() != TAP_IRSHIFT) {
+                       jlink_end_state(TAP_IRSHIFT);
+                       jlink_state_move();
+               }
+       } else {
+               if (tap_get_state() != TAP_DRSHIFT) {
+                       jlink_end_state(TAP_DRSHIFT);
+                       jlink_state_move();
+               }
+       }
 
        jlink_end_state(cmd->cmd.scan->end_state);
 
-       scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
-       DEBUG_JTAG_IO("scan input, length = %d", scan_size);
+       struct scan_field *field = cmd->cmd.scan->fields;
+       unsigned scan_size = 0;
+
+       for (int i = 0; i < cmd->cmd.scan->num_fields; i++, field++) {
+               scan_size += field->num_bits;
+               DEBUG_JTAG_IO("%s%s field %d/%d %d bits",
+                       field->in_value ? "in" : "",
+                       field->out_value ? "out" : "",
+                       i,
+                       cmd->cmd.scan->num_fields,
+                       field->num_bits);
+
+               if (i == cmd->cmd.scan->num_fields - 1 && tap_get_state() != tap_get_end_state()) {
+                       /* Last field, and we're leaving IRSHIFT/DRSHIFT. Clock last bit during tap
+                        * movement. This last field can't have length zero, it was checked above. */
+                       jlink_clock_data(field->out_value,
+                                        0,
+                                        NULL,
+                                        0,
+                                        field->in_value,
+                                        0,
+                                        field->num_bits - 1);
+                       uint8_t last_bit = 0;
+                       if (field->out_value)
+                               bit_copy(&last_bit, 0, field->out_value, field->num_bits - 1, 1);
+                       uint8_t tms_bits = 0x01;
+                       jlink_clock_data(&last_bit,
+                                        0,
+                                        &tms_bits,
+                                        0,
+                                        field->in_value,
+                                        field->num_bits - 1,
+                                        1);
+                       tap_set_state(tap_state_transition(tap_get_state(), 1));
+                       jlink_clock_data(NULL,
+                                        0,
+                                        &tms_bits,
+                                        1,
+                                        NULL,
+                                        0,
+                                        1);
+                       tap_set_state(tap_state_transition(tap_get_state(), 0));
+               } else
+                       jlink_clock_data(field->out_value,
+                                        0,
+                                        NULL,
+                                        0,
+                                        field->in_value,
+                                        0,
+                                        field->num_bits);
+       }
+
+       if (tap_get_state() != tap_get_end_state()) {
+               jlink_end_state(tap_get_end_state());
+               jlink_state_move();
+       }
 
-       type = jtag_scan_type(cmd->cmd.scan);
-       jlink_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size, cmd->cmd.scan);
+       DEBUG_JTAG_IO("%s scan, %i bits, end in %s",
+               (cmd->cmd.scan->ir_scan) ? "IR" : "DR", scan_size,
+               tap_state_name(tap_get_end_state()));
 }
 
 static void jlink_execute_reset(struct jtag_command *cmd)
@@ -155,21 +250,24 @@ static void jlink_execute_reset(struct jtag_command *cmd)
        DEBUG_JTAG_IO("reset trst: %i srst %i", cmd->cmd.reset->trst,
                cmd->cmd.reset->srst);
 
-       jlink_tap_execute();
+       jlink_flush();
        jlink_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
-       jlink_tap_execute();
+       jlink_flush();
 }
 
 static void jlink_execute_sleep(struct jtag_command *cmd)
 {
        DEBUG_JTAG_IO("sleep %" PRIi32 "", cmd->cmd.sleep->us);
-       jlink_tap_execute();
+       jlink_flush();
        jtag_sleep(cmd->cmd.sleep->us);
 }
 
 static int jlink_execute_command(struct jtag_command *cmd)
 {
        switch (cmd->type) {
+               case JTAG_STABLECLOCKS:
+                       jlink_execute_stableclocks(cmd);
+                       break;
                case JTAG_RUNTEST:
                        jlink_execute_runtest(cmd);
                        break;
@@ -210,18 +308,18 @@ static int jlink_execute_queue(void)
                cmd = cmd->next;
        }
 
-       return jlink_tap_execute();
+       return jlink_flush();
 }
 
 static int jlink_speed(int speed)
 {
        int ret;
        uint32_t freq;
-       uint16_t div;
+       uint16_t divider;
        int max_speed;
 
        if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_SPEEDS)) {
-               ret = jaylink_get_speeds(devh, &freq, &div);
+               ret = jaylink_get_speeds(devh, &freq, &divider);
 
                if (ret != JAYLINK_OK) {
                        LOG_ERROR("jaylink_get_speeds() failed: %s.",
@@ -230,7 +328,7 @@ static int jlink_speed(int speed)
                }
 
                freq = freq / 1000;
-               max_speed = freq / div;
+               max_speed = freq / divider;
        } else {
                max_speed = JLINK_MAX_SPEED;
        }
@@ -321,7 +419,7 @@ static int select_interface(void)
                return ERROR_JTAG_INIT_FAILED;
        }
 
-       ret = jaylink_select_interface(devh, iface);
+       ret = jaylink_select_interface(devh, iface, NULL);
 
        if (ret < 0) {
                LOG_ERROR("jaylink_select_interface() failed: %s.",
@@ -414,6 +512,8 @@ static int jlink_init(void)
        char *firmware_version;
        struct jaylink_hardware_version hwver;
        struct jaylink_hardware_status hwstatus;
+       enum jaylink_usb_address address;
+       size_t length;
 
        ret = jaylink_init(&jayctx);
 
@@ -438,24 +538,42 @@ static int jlink_init(void)
                LOG_INFO("No device selected, using first device.");
 
        for (i = 0; devs[i]; i++) {
-               jaylink_device_get_serial_number(devs[i], &tmp);
-               ret = jaylink_device_get_usb_address(devs[i]);
+               if (use_serial_number) {
+                       ret = jaylink_device_get_serial_number(devs[i], &tmp);
+
+                       if (ret == JAYLINK_ERR_NOT_AVAILABLE) {
+                               continue;
+                       } else if (ret != JAYLINK_OK) {
+                               LOG_WARNING("jaylink_device_get_serial_number() failed: %s.",
+                                       jaylink_strerror_name(ret));
+                               continue;
+                       }
 
-               if (use_usb_address && usb_address != ret)
-                       continue;
+                       if (serial_number != tmp)
+                               continue;
+               }
+
+               if (use_usb_address) {
+                       ret = jaylink_device_get_usb_address(devs[i], &address);
+
+                       if (ret != JAYLINK_OK) {
+                               LOG_WARNING("jaylink_device_get_usb_address() failed: %s.",
+                                       jaylink_strerror_name(ret));
+                               continue;
+                       }
 
-               if (use_serial_number && tmp != serial_number)
-                       continue;
+                       if (usb_address != address)
+                               continue;
+               }
 
                ret = jaylink_open(devs[i], &devh);
 
-               if (ret != JAYLINK_OK) {
-                       LOG_ERROR("Failed to open device: %s.", jaylink_strerror_name(ret));
-                       continue;
+               if (ret == JAYLINK_OK) {
+                       found_device = true;
+                       break;
                }
 
-               found_device = true;
-               break;
+               LOG_ERROR("Failed to open device: %s.", jaylink_strerror_name(ret));
        }
 
        jaylink_free_device_list(devs, 1);
@@ -471,19 +589,19 @@ static int jlink_init(void)
         * some devices are known to be sensitive regarding the order.
         */
 
-       ret = jaylink_get_firmware_version(devh, &firmware_version);
+       ret = jaylink_get_firmware_version(devh, &firmware_version, &length);
 
-       if (ret > 0) {
-               LOG_INFO("%s", firmware_version);
-               free(firmware_version);
-       } else if (!ret) {
-               LOG_WARNING("Device responds empty firmware version string.");
-       } else {
+       if (ret != JAYLINK_OK) {
                LOG_ERROR("jaylink_get_firmware_version() failed: %s.",
                        jaylink_strerror_name(ret));
                jaylink_close(devh);
                jaylink_exit(jayctx);
                return ERROR_JTAG_INIT_FAILED;
+       } else if (length > 0) {
+               LOG_INFO("%s", firmware_version);
+               free(firmware_version);
+       } else {
+               LOG_WARNING("Device responds empty firmware version string.");
        }
 
        memset(caps, 0, JAYLINK_DEV_EXT_CAPS_SIZE);
@@ -599,10 +717,10 @@ static int jlink_init(void)
                 * if the first tap move is not divisible by 8, so we send a TLR on
                 * first power up.
                 */
-               for (i = 0; i < 8; i++)
-                       jlink_tap_append_step(1, 0);
+               uint8_t tms = 0xff;
+               jlink_clock_data(NULL, 0, &tms, 0, NULL, 0, 8);
 
-               jlink_tap_execute();
+               jlink_flush();
        }
 
        return ERROR_OK;
@@ -650,18 +768,13 @@ static void jlink_end_state(tap_state_t state)
 /* Goes to the end state. */
 static void jlink_state_move(void)
 {
-       int i;
-       int tms = 0;
        uint8_t tms_scan;
        uint8_t tms_scan_bits;
 
        tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
        tms_scan_bits = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
 
-       for (i = 0; i < tms_scan_bits; i++) {
-               tms = (tms_scan >> i) & 1;
-               jlink_tap_append_step(tms, 0);
-       }
+       jlink_clock_data(NULL, 0, &tms_scan, 0, NULL, 0, tms_scan_bits);
 
        tap_set_state(tap_get_end_state());
 }
@@ -669,12 +782,13 @@ static void jlink_state_move(void)
 static void jlink_path_move(int num_states, tap_state_t *path)
 {
        int i;
+       uint8_t tms = 0xff;
 
        for (i = 0; i < num_states; i++) {
                if (path[i] == tap_state_transition(tap_get_state(), false))
-                       jlink_tap_append_step(0, 0);
+                       jlink_clock_data(NULL, 0, NULL, 0, NULL, 0, 1);
                else if (path[i] == tap_state_transition(tap_get_state(), true))
-                       jlink_tap_append_step(1, 0);
+                       jlink_clock_data(NULL, 0, &tms, 0, NULL, 0, 1);
                else {
                        LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition.",
                                tap_state_name(tap_get_state()), tap_state_name(path[i]));
@@ -687,13 +801,19 @@ static void jlink_path_move(int num_states, tap_state_t *path)
        tap_set_end_state(tap_get_state());
 }
 
-static void jlink_runtest(int num_cycles)
+static void jlink_stableclocks(int num_cycles)
 {
        int i;
 
-       tap_state_t saved_end_state = tap_get_end_state();
+       uint8_t tms = tap_get_state() == TAP_RESET;
+       /* Execute num_cycles. */
+       for (i = 0; i < num_cycles; i++)
+               jlink_clock_data(NULL, 0, &tms, 0, NULL, 0, 1);
+}
 
-       jlink_tap_ensure_space(1, num_cycles + 16);
+static void jlink_runtest(int num_cycles)
+{
+       tap_state_t saved_end_state = tap_get_end_state();
 
        /* Only do a state_move when we're not already in IDLE. */
        if (tap_get_state() != TAP_IDLE) {
@@ -702,9 +822,7 @@ static void jlink_runtest(int num_cycles)
                /* num_cycles--; */
        }
 
-       /* Execute num_cycles. */
-       for (i = 0; i < num_cycles; i++)
-               jlink_tap_append_step(0, 0);
+       jlink_stableclocks(num_cycles);
 
        /* Finish in end_state. */
        jlink_end_state(saved_end_state);
@@ -713,36 +831,6 @@ static void jlink_runtest(int num_cycles)
                jlink_state_move();
 }
 
-static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer,
-               int scan_size, struct scan_command *command)
-{
-       tap_state_t saved_end_state;
-
-       jlink_tap_ensure_space(1, scan_size + 16);
-
-       saved_end_state = tap_get_end_state();
-
-       /* Move to appropriate scan state. */
-       jlink_end_state(ir_scan ? TAP_IRSHIFT : TAP_DRSHIFT);
-
-       /* Only move if we're not already there. */
-       if (tap_get_state() != tap_get_end_state())
-               jlink_state_move();
-
-       jlink_end_state(saved_end_state);
-
-       /* Scan. */
-       jlink_tap_append_scan(scan_size, buffer, command);
-
-       /* We are in Exit1, go to Pause. */
-       jlink_tap_append_step(0, 0);
-
-       tap_set_state(ir_scan ? TAP_IRPAUSE : TAP_DRPAUSE);
-
-       if (tap_get_state() != tap_get_end_state())
-               jlink_state_move();
-}
-
 static void jlink_reset(int trst, int srst)
 {
        LOG_DEBUG("TRST: %i, SRST: %i.", trst, srst);
@@ -763,21 +851,25 @@ static void jlink_reset(int trst, int srst)
 
 COMMAND_HANDLER(jlink_usb_command)
 {
+       int tmp;
+
        if (CMD_ARGC != 1) {
                command_print(CMD_CTX, "Need exactly one argument for jlink usb.");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
-       if (sscanf(CMD_ARGV[0], "%" SCNd8, &usb_address) != 1) {
+       if (sscanf(CMD_ARGV[0], "%i", &tmp) != 1) {
                command_print(CMD_CTX, "Invalid USB address: %s.", CMD_ARGV[0]);
                return ERROR_FAIL;
        }
 
-       if (usb_address > JAYLINK_USB_ADDRESS_3) {
+       if (tmp < JAYLINK_USB_ADDRESS_0 || tmp > JAYLINK_USB_ADDRESS_3) {
                command_print(CMD_CTX, "Invalid USB address: %s.", CMD_ARGV[0]);
                return ERROR_FAIL;
        }
 
+       usb_address = tmp;
+
        use_serial_number = false;
        use_usb_address = true;
 
@@ -1064,26 +1156,26 @@ static uint32_t calculate_trace_buffer_size(void)
        return tmp & 0xffffff00;
 }
 
-static bool check_trace_freq(uint32_t freq, uint32_t div, uint32_t trace_freq)
+static bool check_trace_freq(struct jaylink_swo_speed speed,
+               uint32_t trace_freq)
 {
        double min;
        double deviation;
+       uint32_t divider;
 
-       min = fabs(1.0 - (freq / ((double)trace_freq * div)));
+       min = fabs(1.0 - (speed.freq / ((double)trace_freq * speed.min_div)));
 
-       while (freq / div > 0) {
-               deviation = fabs(1.0 - (freq / ((double)trace_freq * div)));
+       for (divider = speed.min_div; divider < speed.max_div; divider++) {
+               deviation = fabs(1.0 - (speed.freq / ((double)trace_freq * divider)));
 
                if (deviation < 0.03) {
                        LOG_DEBUG("Found suitable frequency divider %u with deviation of "
-                               "%.02f %%.", div, deviation);
+                               "%.02f %%.", divider, deviation);
                        return true;
                }
 
                if (deviation < min)
                        min = deviation;
-
-               div++;
        }
 
        LOG_ERROR("Selected trace frequency is not supported by the device. "
@@ -1099,8 +1191,7 @@ static int config_trace(bool enabled, enum tpio_pin_protocol pin_protocol,
 {
        int ret;
        uint32_t buffer_size;
-       uint32_t freq;
-       uint32_t div;
+       struct jaylink_swo_speed speed;
 
        if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_SWO)) {
                LOG_ERROR("Trace capturing is not supported by the device.");
@@ -1139,7 +1230,7 @@ static int config_trace(bool enabled, enum tpio_pin_protocol pin_protocol,
                return ERROR_FAIL;
        }
 
-       ret = jaylink_swo_get_speeds(devh, JAYLINK_SWO_MODE_UART, &freq, &div);
+       ret = jaylink_swo_get_speeds(devh, JAYLINK_SWO_MODE_UART, &speed);
 
        if (ret != JAYLINK_OK) {
                LOG_ERROR("jaylink_swo_get_speeds() failed: %s.",
@@ -1148,9 +1239,9 @@ static int config_trace(bool enabled, enum tpio_pin_protocol pin_protocol,
        }
 
        if (!*trace_freq)
-               *trace_freq = freq / div;
+               *trace_freq = speed.freq / speed.min_div;
 
-       if (!check_trace_freq(freq, div, *trace_freq))
+       if (!check_trace_freq(speed, *trace_freq))
                return ERROR_FAIL;
 
        LOG_DEBUG("Using %u bytes device memory for trace capturing.", buffer_size);
@@ -1568,22 +1659,19 @@ static int jlink_swd_init(void)
        return ERROR_OK;
 }
 
-static void jlink_swd_write_reg(struct adiv5_dap *dap, uint8_t cmd,
-               uint32_t value)
+static void jlink_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk)
 {
        assert(!(cmd & SWD_CMD_RnW));
-       jlink_swd_queue_cmd(dap, cmd, NULL, value);
+       jlink_swd_queue_cmd(cmd, NULL, value, ap_delay_clk);
 }
 
-static void jlink_swd_read_reg(struct adiv5_dap *dap, uint8_t cmd,
-               uint32_t *value)
+static void jlink_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay_clk)
 {
        assert(cmd & SWD_CMD_RnW);
-       jlink_swd_queue_cmd(dap, cmd, value, 0);
+       jlink_swd_queue_cmd(cmd, value, 0, ap_delay_clk);
 }
 
-static int_least32_t jlink_swd_frequency(struct adiv5_dap *dap,
-               int_least32_t hz)
+static int_least32_t jlink_swd_frequency(int_least32_t hz)
 {
        if (hz > 0)
                jlink_speed(hz / 1000);
@@ -1601,10 +1689,14 @@ static uint8_t tdi_buffer[JLINK_TAP_BUFFER_SIZE];
 static uint8_t tdo_buffer[JLINK_TAP_BUFFER_SIZE];
 
 struct pending_scan_result {
-       int first; /* First bit position in tdo_buffer to read. */
-       int length; /* Number of bits to read. */
-       struct scan_command *command; /* Corresponding scan command. */
+       /** First bit position in tdo_buffer to read. */
+       unsigned first;
+       /** Number of bits to read. */
+       unsigned length;
+       /** Location to store the result */
        void *buffer;
+       /** Offset in the destination buffer */
+       unsigned buffer_offset;
 };
 
 #define MAX_PENDING_SCAN_RESULTS 256
@@ -1616,69 +1708,53 @@ static void jlink_tap_init(void)
 {
        tap_length = 0;
        pending_scan_results_length = 0;
+       memset(tms_buffer, 0, sizeof(tms_buffer));
+       memset(tdi_buffer, 0, sizeof(tdi_buffer));
 }
 
-static void jlink_tap_ensure_space(int scans, int bits)
-{
-       int available_scans = MAX_PENDING_SCAN_RESULTS - pending_scan_results_length;
-       int available_bits = JLINK_TAP_BUFFER_SIZE * 8 - tap_length - 32;
-
-       if (scans > available_scans || bits > available_bits)
-               jlink_tap_execute();
-}
-
-static void jlink_tap_append_step(int tms, int tdi)
+static void jlink_clock_data(const uint8_t *out, unsigned out_offset,
+                            const uint8_t *tms_out, unsigned tms_offset,
+                            uint8_t *in, unsigned in_offset,
+                            unsigned length)
 {
-       int index_var = tap_length / 8;
-
-       assert(index_var < JLINK_TAP_BUFFER_SIZE);
-
-       int bit_index = tap_length % 8;
-       uint8_t bit = 1 << bit_index;
-
-       /* We do not pad TMS, so be sure to initialize all bits. */
-       if (0 == bit_index)
-               tms_buffer[index_var] = tdi_buffer[index_var] = 0;
-
-       if (tms)
-               tms_buffer[index_var] |= bit;
-       else
-               tms_buffer[index_var] &= ~bit;
-
-       if (tdi)
-               tdi_buffer[index_var] |= bit;
-       else
-               tdi_buffer[index_var] &= ~bit;
+       do {
+               unsigned available_length = JLINK_TAP_BUFFER_SIZE - tap_length / 8;
+
+               if (!available_length ||
+                   (in && pending_scan_results_length == MAX_PENDING_SCAN_RESULTS)) {
+                       if (jlink_flush() != ERROR_OK)
+                               return;
+                       available_length = JLINK_TAP_BUFFER_SIZE;
+               }
 
-       tap_length++;
-}
+               struct pending_scan_result *pending_scan_result =
+                       &pending_scan_results_buffer[pending_scan_results_length];
 
-static void jlink_tap_append_scan(int length, uint8_t *buffer,
-               struct scan_command *command)
-{
-       struct pending_scan_result *pending_scan_result =
-               &pending_scan_results_buffer[pending_scan_results_length];
-       int i;
+               unsigned scan_length = length > available_length ?
+                       available_length : length;
 
-       pending_scan_result->first = tap_length;
-       pending_scan_result->length = length;
-       pending_scan_result->command = command;
-       pending_scan_result->buffer = buffer;
+               if (out)
+                       buf_set_buf(out, out_offset, tdi_buffer, tap_length, scan_length);
+               if (tms_out)
+                       buf_set_buf(tms_out, tms_offset, tms_buffer, tap_length, scan_length);
 
-       for (i = 0; i < length; i++) {
-               int tms = (i < (length - 1)) ? 0 : 1;
-               int tdi = (buffer[i / 8] & (1 << (i % 8))) != 0;
-               jlink_tap_append_step(tms, tdi);
-       }
+               if (in) {
+                       pending_scan_result->first = tap_length;
+                       pending_scan_result->length = scan_length;
+                       pending_scan_result->buffer = in;
+                       pending_scan_result->buffer_offset = in_offset;
+                       pending_scan_results_length++;
+               }
 
-       pending_scan_results_length++;
+               tap_length += scan_length;
+               out_offset += scan_length;
+               tms_offset += scan_length;
+               in_offset += scan_length;
+               length -= scan_length;
+       } while (length > 0);
 }
 
-/*
- * Pad and send a tap sequence to the device, and receive the answer. For the
- * purpose of padding we assume that we are in idle or pause state.
- */
-static int jlink_tap_execute(void)
+static int jlink_flush(void)
 {
        int i;
        int ret;
@@ -1689,9 +1765,6 @@ static int jlink_tap_execute(void)
        jlink_last_state = jtag_debug_state_machine(tms_buffer, tdi_buffer,
                tap_length, jlink_last_state);
 
-       jlink_last_state = jtag_debug_state_machine(tms_buffer, tdi_buffer,
-               tap_length, jlink_last_state);
-
        ret = jaylink_jtag_io(devh, tms_buffer, tdi_buffer, tdo_buffer,
                tap_length, jtag_command_version);
 
@@ -1702,24 +1775,12 @@ static int jlink_tap_execute(void)
        }
 
        for (i = 0; i < pending_scan_results_length; i++) {
-               struct pending_scan_result *pending_scan_result = &pending_scan_results_buffer[i];
-               uint8_t *buffer = pending_scan_result->buffer;
-               int length = pending_scan_result->length;
-               int first = pending_scan_result->first;
-               struct scan_command *command = pending_scan_result->command;
-
-               /* Copy to buffer. */
-               buf_set_buf(tdo_buffer, first, buffer, 0, length);
-
-               DEBUG_JTAG_IO("Pending scan result, length = %d.", length);
+               struct pending_scan_result *p = &pending_scan_results_buffer[i];
 
-               if (jtag_read_buffer(buffer, command) != ERROR_OK) {
-                       jlink_tap_init();
-                       return ERROR_JTAG_QUEUE_FAILED;
-               }
+               buf_set_buf(tdo_buffer, p->first, p->buffer,
+                           p->buffer_offset, p->length);
 
-               if (pending_scan_result->buffer != NULL)
-                       free(pending_scan_result->buffer);
+               DEBUG_JTAG_IO("Pending scan result, length = %d.", p->length);
        }
 
        jlink_tap_init();
@@ -1762,7 +1823,7 @@ static void jlink_queue_data_in(uint32_t len)
        tap_length += len;
 }
 
-static int jlink_swd_switch_seq(struct adiv5_dap *dap, enum swd_special_seq seq)
+static int jlink_swd_switch_seq(enum swd_special_seq seq)
 {
        const uint8_t *s;
        unsigned int s_len;
@@ -1793,7 +1854,7 @@ static int jlink_swd_switch_seq(struct adiv5_dap *dap, enum swd_special_seq seq)
        return ERROR_OK;
 }
 
-static int jlink_swd_run_queue(struct adiv5_dap *dap)
+static int jlink_swd_run_queue(void)
 {
        int i;
        int ret;
@@ -1849,14 +1910,13 @@ skip:
        return ret;
 }
 
-static void jlink_swd_queue_cmd(struct adiv5_dap *dap, uint8_t cmd,
-               uint32_t *dst, uint32_t data)
+static void jlink_swd_queue_cmd(uint8_t cmd, uint32_t *dst, uint32_t data, uint32_t ap_delay_clk)
 {
        uint8_t data_parity_trn[DIV_ROUND_UP(32 + 1, 8)];
-       if (tap_length + 46 + 8 + dap->ap[dap_ap_get_select(dap)].memaccess_tck >= sizeof(tdi_buffer) * 8 ||
+       if (tap_length + 46 + 8 + ap_delay_clk >= sizeof(tdi_buffer) * 8 ||
            pending_scan_results_length == MAX_PENDING_SCAN_RESULTS) {
                /* Not enough room in the queue. Run the queue. */
-               queued_retval = jlink_swd_run_queue(dap);
+               queued_retval = jlink_swd_run_queue();
        }
 
        if (queued_retval != ERROR_OK)
@@ -1889,7 +1949,7 @@ static void jlink_swd_queue_cmd(struct adiv5_dap *dap, uint8_t cmd,
 
        /* Insert idle cycles after AP accesses to avoid WAIT. */
        if (cmd & SWD_CMD_APnDP)
-               jlink_queue_data_out(NULL, dap->ap[dap_ap_get_select(dap)].memaccess_tck);
+               jlink_queue_data_out(NULL, ap_delay_clk);
 }
 
 static const struct swd_driver jlink_swd = {