]> git.sur5r.net Git - openocd/blobdiff - src/target/mips_ejtag.c
Remove FSF address from GPL notices
[openocd] / src / target / mips_ejtag.c
index 84ad5294b0655ab65e80573bd1c313a0a89a74d4..594711fb53be06bede8400d3c48c4ee061c5aac5 100644 (file)
  *   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.,                                       *
- *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  ***************************************************************************/
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
 #include "mips32.h"
 #include "mips_ejtag.h"
+#include "mips32_dmaacc.h"
 
-int mips_ejtag_set_instr(struct mips_ejtag *ejtag_info, int new_instr)
+void mips_ejtag_set_instr(struct mips_ejtag *ejtag_info, int new_instr)
 {
        struct jtag_tap *tap;
 
        tap = ejtag_info->tap;
-       if (tap == NULL)
-               return ERROR_FAIL;
+       assert(tap != NULL);
 
-       if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) != (uint32_t)new_instr)
-       {
+       if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) != (uint32_t)new_instr) {
                struct scan_field field;
                uint8_t t[4];
 
@@ -48,57 +46,87 @@ int mips_ejtag_set_instr(struct mips_ejtag *ejtag_info, int new_instr)
 
                jtag_add_ir_scan(tap, &field, TAP_IDLE);
        }
-
-       return ERROR_OK;
 }
 
 int mips_ejtag_get_idcode(struct mips_ejtag *ejtag_info, uint32_t *idcode)
 {
        struct scan_field field;
+       uint8_t r[4];
 
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_IDCODE);
 
        field.num_bits = 32;
        field.out_value = NULL;
-       field.in_value = (void*)idcode;
+       field.in_value = r;
 
        jtag_add_dr_scan(ejtag_info->tap, 1, &field, TAP_IDLE);
 
-       if (jtag_execute_queue() != ERROR_OK)
-       {
+       int retval;
+       retval = jtag_execute_queue();
+       if (retval != ERROR_OK) {
                LOG_ERROR("register read failed");
+               return retval;
        }
 
+       *idcode = buf_get_u32(field.in_value, 0, 32);
+
        return ERROR_OK;
 }
 
 static int mips_ejtag_get_impcode(struct mips_ejtag *ejtag_info, uint32_t *impcode)
 {
        struct scan_field field;
+       uint8_t r[4];
 
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_IMPCODE);
 
        field.num_bits = 32;
        field.out_value = NULL;
-       field.in_value = (void*)impcode;
+       field.in_value = r;
 
        jtag_add_dr_scan(ejtag_info->tap, 1, &field, TAP_IDLE);
 
-       if (jtag_execute_queue() != ERROR_OK)
-       {
+       int retval;
+       retval = jtag_execute_queue();
+       if (retval != ERROR_OK) {
                LOG_ERROR("register read failed");
+               return retval;
        }
 
+       *impcode = buf_get_u32(field.in_value, 0, 32);
+
        return ERROR_OK;
 }
 
+void mips_ejtag_add_scan_96(struct mips_ejtag *ejtag_info, uint32_t ctrl, uint32_t data, uint8_t *in_scan_buf)
+{
+       assert(ejtag_info->tap != NULL);
+       struct jtag_tap *tap = ejtag_info->tap;
+
+       struct scan_field field;
+       uint8_t out_scan[12];
+
+       /* processor access "all" register 96 bit */
+       field.num_bits = 96;
+
+       field.out_value = out_scan;
+       buf_set_u32(out_scan, 0, 32, ctrl);
+       buf_set_u32(out_scan + 4, 0, 32, data);
+       buf_set_u32(out_scan + 8, 0, 32, 0);
+
+       field.in_value = in_scan_buf;
+
+       jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
+
+       keep_alive();
+}
+
 int mips_ejtag_drscan_32(struct mips_ejtag *ejtag_info, uint32_t *data)
 {
        struct jtag_tap *tap;
        tap  = ejtag_info->tap;
+       assert(tap != NULL);
 
-       if (tap == NULL)
-               return ERROR_FAIL;
        struct scan_field field;
        uint8_t t[4], r[4];
        int retval;
@@ -110,8 +138,8 @@ int mips_ejtag_drscan_32(struct mips_ejtag *ejtag_info, uint32_t *data)
 
        jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
 
-       if ((retval = jtag_execute_queue()) != ERROR_OK)
-       {
+       retval = jtag_execute_queue();
+       if (retval != ERROR_OK) {
                LOG_ERROR("register read failed");
                return retval;
        }
@@ -123,13 +151,30 @@ int mips_ejtag_drscan_32(struct mips_ejtag *ejtag_info, uint32_t *data)
        return ERROR_OK;
 }
 
+void mips_ejtag_drscan_32_out(struct mips_ejtag *ejtag_info, uint32_t data)
+{
+       uint8_t t[4];
+       struct jtag_tap *tap;
+       tap  = ejtag_info->tap;
+       assert(tap != NULL);
+
+       struct scan_field field;
+
+       field.num_bits = 32;
+       field.out_value = t;
+       buf_set_u32(t, 0, field.num_bits, data);
+
+       field.in_value = NULL;
+
+       jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
+}
+
 int mips_ejtag_drscan_8(struct mips_ejtag *ejtag_info, uint32_t *data)
 {
        struct jtag_tap *tap;
        tap  = ejtag_info->tap;
+       assert(tap != NULL);
 
-       if (tap == NULL)
-               return ERROR_FAIL;
        struct scan_field field;
        uint8_t t[4] = {0, 0, 0, 0}, r[4];
        int retval;
@@ -141,66 +186,79 @@ int mips_ejtag_drscan_8(struct mips_ejtag *ejtag_info, uint32_t *data)
 
        jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
 
-       if ((retval = jtag_execute_queue()) != ERROR_OK)
-       {
+       retval = jtag_execute_queue();
+       if (retval != ERROR_OK) {
                LOG_ERROR("register read failed");
                return retval;
        }
 
        *data = buf_get_u32(field.in_value, 0, 32);
 
-       keep_alive();
-
        return ERROR_OK;
 }
 
-static int mips_ejtag_step_enable(struct mips_ejtag *ejtag_info)
+void mips_ejtag_drscan_8_out(struct mips_ejtag *ejtag_info, uint8_t data)
 {
-       static const uint32_t code[] = {
-                       MIPS32_MTC0(1,31,0),                    /* move $1 to COP0 DeSave */
-                       MIPS32_MFC0(1,23,0),                    /* move COP0 Debug to $1 */
-                       MIPS32_ORI(1,1,0x0100),                 /* set SSt bit in debug reg */
-                       MIPS32_MTC0(1,23,0),                    /* move $1 to COP0 Debug */
-                       MIPS32_B(NEG16(5)),
-                       MIPS32_MFC0(1,31,0),                    /* move COP0 DeSave to $1 */
-       };
-
-       mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               0, NULL, 0, NULL, 1);
+       struct jtag_tap *tap;
+       tap  = ejtag_info->tap;
+       assert(tap != NULL);
 
-       return ERROR_OK;
-}
+       struct scan_field field;
 
-static int mips_ejtag_step_disable(struct mips_ejtag *ejtag_info)
-{
-       static const uint32_t code[] = {
-                       MIPS32_MTC0(15,31,0),                                                   /* move $15 to COP0 DeSave */
-                       MIPS32_LUI(15,UPPER16(MIPS32_PRACC_STACK)),             /* $15 = MIPS32_PRACC_STACK */
-                       MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)),
-                       MIPS32_SW(1,0,15),                                                              /* sw $1,($15) */
-                       MIPS32_SW(2,0,15),                                                              /* sw $2,($15) */
-                       MIPS32_MFC0(1,23,0),                                                    /* move COP0 Debug to $1 */
-                       MIPS32_LUI(2,0xFFFF),                                                   /* $2 = 0xfffffeff */
-                       MIPS32_ORI(2,2,0xFEFF),
-                       MIPS32_AND(1,1,2),
-                       MIPS32_MTC0(1,23,0),                                                    /* move $1 to COP0 Debug */
-                       MIPS32_LW(2,0,15),
-                       MIPS32_LW(1,0,15),
-                       MIPS32_B(NEG16(13)),
-                       MIPS32_MFC0(15,31,0),                                                   /* move COP0 DeSave to $15 */
-       };
-
-       mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               0, NULL, 0, NULL, 1);
+       field.num_bits = 8;
+       field.out_value = &data;
+       field.in_value = NULL;
 
-       return ERROR_OK;
+       jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
 }
 
+/* Set (to enable) or clear (to disable stepping) the SSt bit (bit 8) in Cp0 Debug reg (reg 23, sel 0) */
 int mips_ejtag_config_step(struct mips_ejtag *ejtag_info, int enable_step)
 {
-       if (enable_step)
-               return mips_ejtag_step_enable(ejtag_info);
-       return mips_ejtag_step_disable(ejtag_info);
+       struct pracc_queue_info ctx = {.max_code = 7};
+       pracc_queue_init(&ctx);
+       if (ctx.retval != ERROR_OK)
+               goto exit;
+
+       pracc_add(&ctx, 0, MIPS32_MFC0(8, 23, 0));                      /* move COP0 Debug to $8 */
+       pracc_add(&ctx, 0, MIPS32_ORI(8, 8, 0x0100));                   /* set SSt bit in debug reg */
+       if (!enable_step)
+               pracc_add(&ctx, 0, MIPS32_XORI(8, 8, 0x0100));          /* clear SSt bit in debug reg */
+
+       pracc_add(&ctx, 0, MIPS32_MTC0(8, 23, 0));                      /* move $8 to COP0 Debug */
+       pracc_add(&ctx, 0, MIPS32_LUI(8, UPPER16(ejtag_info->reg8)));           /* restore upper 16 bits  of $8 */
+       pracc_add(&ctx, 0, MIPS32_B(NEG16((ctx.code_count + 1))));                      /* jump to start */
+       pracc_add(&ctx, 0, MIPS32_ORI(8, 8, LOWER16(ejtag_info->reg8)));        /* restore lower 16 bits of $8 */
+
+       ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL);
+exit:
+       pracc_queue_free(&ctx);
+       return ctx.retval;
+}
+
+/*
+ * Disable memory protection for 0xFF20.0000–0xFF3F.FFFF
+ * It is needed by EJTAG 1.5-2.0, especially for BMIPS CPUs
+ * For example bcm7401 and others. At leas on some
+ * CPUs, DebugMode wont start if this bit is not removed.
+ */
+static int disable_dcr_mp(struct mips_ejtag *ejtag_info)
+{
+       uint32_t dcr;
+       int retval;
+
+       retval = mips32_dmaacc_read_mem(ejtag_info, EJTAG_DCR, 4, 1, &dcr);
+       if (retval != ERROR_OK)
+               goto error;
+
+       dcr &= ~EJTAG_DCR_MP;
+       retval = mips32_dmaacc_write_mem(ejtag_info, EJTAG_DCR, 4, 1, &dcr);
+       if (retval != ERROR_OK)
+               goto error;
+       return ERROR_OK;
+error:
+       LOG_ERROR("Failed to remove DCR MPbit!");
+       return retval;
 }
 
 int mips_ejtag_enter_debug(struct mips_ejtag *ejtag_info)
@@ -208,6 +266,11 @@ int mips_ejtag_enter_debug(struct mips_ejtag *ejtag_info)
        uint32_t ejtag_ctrl;
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
 
+       if (ejtag_info->ejtag_version == EJTAG_VERSION_20) {
+               if (disable_dcr_mp(ejtag_info) != ERROR_OK)
+                       goto error;
+       }
+
        /* set debug break bit */
        ejtag_ctrl = ejtag_info->ejtag_ctrl | EJTAG_CTRL_JTAGBRK;
        mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
@@ -217,100 +280,174 @@ int mips_ejtag_enter_debug(struct mips_ejtag *ejtag_info)
        mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
        LOG_DEBUG("ejtag_ctrl: 0x%8.8" PRIx32 "", ejtag_ctrl);
        if ((ejtag_ctrl & EJTAG_CTRL_BRKST) == 0)
-               LOG_DEBUG("Failed to enter Debug Mode!");
+               goto error;
 
        return ERROR_OK;
+error:
+       LOG_ERROR("Failed to enter Debug Mode!");
+       return ERROR_FAIL;
 }
 
 int mips_ejtag_exit_debug(struct mips_ejtag *ejtag_info)
 {
-       uint32_t inst;
-       inst = MIPS32_DRET;
+       uint32_t pracc_list[] = {MIPS32_DRET, 0};
+       struct pracc_queue_info ctx = {.max_code = 1, .pracc_list = pracc_list, .code_count = 1, .store_count = 0};
 
        /* execute our dret instruction */
-       mips32_pracc_exec(ejtag_info, 1, &inst, 0, NULL, 0, NULL, 0);
+       ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL);
 
-       return ERROR_OK;
+       /* pic32mx workaround, false pending at low core clock */
+       jtag_add_sleep(1000);
+       return ctx.retval;
 }
 
-int mips_ejtag_read_debug(struct mips_ejtag *ejtag_info, uint32_t* debug_reg)
+/* mips_ejtag_init_mmr - asign Memory-Mapped Registers depending
+ *                     on EJTAG version.
+ */
+static void mips_ejtag_init_mmr(struct mips_ejtag *ejtag_info)
 {
-       /* read ejtag ECR */
-       static const uint32_t code[] = {
-                       MIPS32_MTC0(15,31,0),                                                   /* move $15 to COP0 DeSave */
-                       MIPS32_LUI(15,UPPER16(MIPS32_PRACC_STACK)),             /* $15 = MIPS32_PRACC_STACK */
-                       MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)),
-                       MIPS32_SW(1,0,15),                                                              /* sw $1,($15) */
-                       MIPS32_SW(2,0,15),                                                              /* sw $2,($15) */
-                       MIPS32_LUI(1,UPPER16(MIPS32_PRACC_PARAM_OUT)),  /* $1 = MIPS32_PRACC_PARAM_OUT */
-                       MIPS32_ORI(1,1,LOWER16(MIPS32_PRACC_PARAM_OUT)),
-                       MIPS32_MFC0(2,23,0),                                                    /* move COP0 Debug to $2 */
-                       MIPS32_SW(2,0,1),
-                       MIPS32_LW(2,0,15),
-                       MIPS32_LW(1,0,15),
-                       MIPS32_B(NEG16(12)),
-                       MIPS32_MFC0(15,31,0),                                                   /* move COP0 DeSave to $15 */
-       };
-
-       mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               0, NULL, 1, debug_reg, 1);
+       if (ejtag_info->ejtag_version == EJTAG_VERSION_20) {
+               ejtag_info->ejtag_ibs_addr      = EJTAG_V20_IBS;
+               ejtag_info->ejtag_iba0_addr     = EJTAG_V20_IBA0;
+               ejtag_info->ejtag_ibc_offs      = EJTAG_V20_IBC_OFFS;
+               ejtag_info->ejtag_ibm_offs      = EJTAG_V20_IBM_OFFS;
+
+               ejtag_info->ejtag_dbs_addr      = EJTAG_V20_DBS;
+               ejtag_info->ejtag_dba0_addr     = EJTAG_V20_DBA0;
+               ejtag_info->ejtag_dbc_offs      = EJTAG_V20_DBC_OFFS;
+               ejtag_info->ejtag_dbm_offs      = EJTAG_V20_DBM_OFFS;
+               ejtag_info->ejtag_dbv_offs      = EJTAG_V20_DBV_OFFS;
+
+               ejtag_info->ejtag_iba_step_size = EJTAG_V20_IBAn_STEP;
+               ejtag_info->ejtag_dba_step_size = EJTAG_V20_DBAn_STEP;
+       } else {
+               ejtag_info->ejtag_ibs_addr      = EJTAG_V25_IBS;
+               ejtag_info->ejtag_iba0_addr     = EJTAG_V25_IBA0;
+               ejtag_info->ejtag_ibm_offs      = EJTAG_V25_IBM_OFFS;
+               ejtag_info->ejtag_ibasid_offs   = EJTAG_V25_IBASID_OFFS;
+               ejtag_info->ejtag_ibc_offs      = EJTAG_V25_IBC_OFFS;
+
+               ejtag_info->ejtag_dbs_addr      = EJTAG_V25_DBS;
+               ejtag_info->ejtag_dba0_addr     = EJTAG_V25_DBA0;
+               ejtag_info->ejtag_dbm_offs      = EJTAG_V25_DBM_OFFS;
+               ejtag_info->ejtag_dbasid_offs   = EJTAG_V25_DBASID_OFFS;
+               ejtag_info->ejtag_dbc_offs      = EJTAG_V25_DBC_OFFS;
+               ejtag_info->ejtag_dbv_offs      = EJTAG_V25_DBV_OFFS;
+
+               ejtag_info->ejtag_iba_step_size = EJTAG_V25_IBAn_STEP;
+               ejtag_info->ejtag_dba_step_size = EJTAG_V25_DBAn_STEP;
+       }
+}
 
-       return ERROR_OK;
+static void ejtag_v20_print_imp(struct mips_ejtag *ejtag_info)
+{
+       LOG_DEBUG("EJTAG v2.0: features:%s%s%s%s%s%s%s%s",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_SDBBP) ? " SDBBP_SPECIAL2" : " SDBBP",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_EADDR_NO32BIT) ? " EADDR>32bit" : " EADDR=32bit",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_COMPLEX_BREAK) ? " COMPLEX_BREAK" : "",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_DCACHE_COH) ? " DCACHE_COH" : " DCACHE_NOT_COH",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_ICACHE_COH) ? " ICACHE_COH" : " ICACHE_NOT_COH",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_NOPB) ? " noPB" : " PB",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_NODB) ? " noDB" : " DB",
+               EJTAG_IMP_HAS(EJTAG_V20_IMP_NOIB) ? " noIB" : " IB");
+       LOG_DEBUG("EJTAG v2.0: Break Channels: %" PRIu8,
+               (uint8_t)((ejtag_info->impcode >> EJTAG_V20_IMP_BCHANNELS_SHIFT) &
+               EJTAG_V20_IMP_BCHANNELS_MASK));
+}
+
+static void ejtag_v26_print_imp(struct mips_ejtag *ejtag_info)
+{
+       LOG_DEBUG("EJTAG v2.6: features:%s%s",
+               EJTAG_IMP_HAS(EJTAG_V26_IMP_R3K) ? " R3k" : " R4k",
+               EJTAG_IMP_HAS(EJTAG_V26_IMP_DINT) ? " DINT" : "");
+}
+
+static void ejtag_main_print_imp(struct mips_ejtag *ejtag_info)
+{
+       LOG_DEBUG("EJTAG main: features:%s%s%s%s%s",
+               EJTAG_IMP_HAS(EJTAG_IMP_ASID8) ? " ASID_8" : "",
+               EJTAG_IMP_HAS(EJTAG_IMP_ASID6) ? " ASID_6" : "",
+               EJTAG_IMP_HAS(EJTAG_IMP_MIPS16) ? " MIPS16" : "",
+               EJTAG_IMP_HAS(EJTAG_IMP_NODMA) ? " noDMA" : " DMA",
+               EJTAG_IMP_HAS(EJTAG_DCR_MIPS64) ? " MIPS64" : " MIPS32");
+
+       switch (ejtag_info->ejtag_version) {
+               case EJTAG_VERSION_20:
+                       ejtag_v20_print_imp(ejtag_info);
+                       break;
+               case EJTAG_VERSION_25:
+               case EJTAG_VERSION_26:
+               case EJTAG_VERSION_31:
+               case EJTAG_VERSION_41:
+               case EJTAG_VERSION_51:
+                       ejtag_v26_print_imp(ejtag_info);
+                       break;
+               default:
+                       break;
+       }
 }
 
 int mips_ejtag_init(struct mips_ejtag *ejtag_info)
 {
-       uint32_t ejtag_version;
+       int retval;
 
-       mips_ejtag_get_impcode(ejtag_info, &ejtag_info->impcode);
+       retval = mips_ejtag_get_impcode(ejtag_info, &ejtag_info->impcode);
+       if (retval != ERROR_OK)
+               return retval;
        LOG_DEBUG("impcode: 0x%8.8" PRIx32 "", ejtag_info->impcode);
 
        /* get ejtag version */
-       ejtag_version = ((ejtag_info->impcode >> 29) & 0x07);
+       ejtag_info->ejtag_version = ((ejtag_info->impcode >> 29) & 0x07);
 
-       switch (ejtag_version)
-       {
-               case 0:
+       switch (ejtag_info->ejtag_version) {
+               case EJTAG_VERSION_20:
                        LOG_DEBUG("EJTAG: Version 1 or 2.0 Detected");
                        break;
-               case 1:
+               case EJTAG_VERSION_25:
                        LOG_DEBUG("EJTAG: Version 2.5 Detected");
                        break;
-               case 2:
+               case EJTAG_VERSION_26:
                        LOG_DEBUG("EJTAG: Version 2.6 Detected");
                        break;
-               case 3:
+               case EJTAG_VERSION_31:
                        LOG_DEBUG("EJTAG: Version 3.1 Detected");
                        break;
+               case EJTAG_VERSION_41:
+                       LOG_DEBUG("EJTAG: Version 4.1 Detected");
+                       break;
+               case EJTAG_VERSION_51:
+                       LOG_DEBUG("EJTAG: Version 5.1 Detected");
+                       break;
                default:
                        LOG_DEBUG("EJTAG: Unknown Version Detected");
                        break;
        }
-       LOG_DEBUG("EJTAG: features:%s%s%s%s%s%s%s",
-               ejtag_info->impcode & EJTAG_IMP_R3K ? " R3k" : " R4k",
-               ejtag_info->impcode & EJTAG_IMP_DINT ? " DINT" : "",
-               ejtag_info->impcode & (1 << 22) ? " ASID_8" : "",
-               ejtag_info->impcode & (1 << 21) ? " ASID_6" : "",
-               ejtag_info->impcode & EJTAG_IMP_MIPS16 ? " MIPS16" : "",
-               ejtag_info->impcode & EJTAG_IMP_NODMA ? " noDMA" : " DMA",
-               ejtag_info->impcode & EJTAG_DCR_MIPS64  ? " MIPS64" : " MIPS32");
+       ejtag_main_print_imp(ejtag_info);
 
-       if ((ejtag_info->impcode & EJTAG_IMP_NODMA) == 0)
-               LOG_DEBUG("EJTAG: DMA Access Mode Support Enabled");
+       if ((ejtag_info->impcode & EJTAG_IMP_NODMA) == 0) {
+               LOG_DEBUG("EJTAG: DMA Access Mode detected. Disabling to "
+                         "workaround current broken code.");
+               ejtag_info->impcode |= EJTAG_IMP_NODMA;
+       }
+
+       ejtag_info->ejtag_ctrl = EJTAG_CTRL_PRACC | EJTAG_CTRL_PROBEN;
+
+       if (ejtag_info->ejtag_version != EJTAG_VERSION_20)
+               ejtag_info->ejtag_ctrl |= EJTAG_CTRL_ROCC | EJTAG_CTRL_SETDEV;
 
-       /* set initial state for ejtag control reg */
-       ejtag_info->ejtag_ctrl = EJTAG_CTRL_ROCC | EJTAG_CTRL_PRACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_SETDEV;
+       ejtag_info->fast_access_save = -1;
+
+       mips_ejtag_init_mmr(ejtag_info);
 
        return ERROR_OK;
 }
 
-int mips_ejtag_fastdata_scan(struct mips_ejtag *ejtag_info, int write, uint32_t *data)
+int mips_ejtag_fastdata_scan(struct mips_ejtag *ejtag_info, int write_t, uint32_t *data)
 {
        struct jtag_tap *tap;
-       tap = ejtag_info->tap;
 
-       if (tap == NULL)
-               return ERROR_FAIL;
+       tap = ejtag_info->tap;
+       assert(tap != NULL);
 
        struct scan_field fields[2];
        uint8_t spracc = 0;
@@ -325,17 +462,18 @@ int mips_ejtag_fastdata_scan(struct mips_ejtag *ejtag_info, int write, uint32_t
        fields[1].num_bits = 32;
        fields[1].out_value = t;
 
-       if (write)
-       {
+       if (write_t) {
                fields[1].in_value = NULL;
                buf_set_u32(t, 0, 32, *data);
-       }
-       else
-       {
+       } else
                fields[1].in_value = (uint8_t *) data;
-       }
 
        jtag_add_dr_scan(tap, 2, fields, TAP_IDLE);
+
+       if (!write_t && data)
+               jtag_add_callback(mips_le_to_h_u32,
+                       (jtag_callback_data_t) data);
+
        keep_alive();
 
        return ERROR_OK;