mips32: Sync Caches to Make Instr Writes Effective
[fw/openocd] / src / target / mips32_pracc.c
index 54274abfa477012f37464d99a714ceb5a769b73f..6b43479fccc601694b1c26afef71b7991498eacb 100644 (file)
@@ -6,6 +6,9 @@
  *                                                                         *
  *   Copyright (C) 2009 by David N. Claffey <dnclaffey@gmail.com>          *
  *                                                                         *
+ *   Copyright (C) 2011 by Drasko DRASKOVIC                                *
+ *   drasko.draskovic@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     *
@@ -74,6 +77,8 @@ Nico Coesel
 #include "config.h"
 #endif
 
+#include <helper/time_support.h>
+
 #include "mips32.h"
 #include "mips32_pracc.h"
 
@@ -108,19 +113,36 @@ static int mips32_pracc_write_mem32(struct mips_ejtag *ejtag_info,
 static int mips32_pracc_write_u32(struct mips_ejtag *ejtag_info,
                uint32_t addr, uint32_t *buf);
 
+static int mips32_pracc_sync_cache(struct mips_ejtag *ejtag_info,
+               uint32_t start_addr, uint32_t end_addr);
+static int mips32_pracc_clean_invalidate_cache(struct mips_ejtag *ejtag_info,
+                                                                                                       uint32_t start_addr, uint32_t end_addr);
+
 static int wait_for_pracc_rw(struct mips_ejtag *ejtag_info, uint32_t *ctrl)
 {
        uint32_t ejtag_ctrl;
+       long long then = timeval_ms();
+       int timeout;
+       int retval;
+
+       /* wait for the PrAcc to become "1" */
+       mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
+       ejtag_ctrl = ejtag_info->ejtag_ctrl;
 
        while (1)
        {
-               mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
-               ejtag_ctrl = ejtag_info->ejtag_ctrl;
-               mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
+               retval = mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
+               if (retval != ERROR_OK)
+                       return retval;
+
                if (ejtag_ctrl & EJTAG_CTRL_PRACC)
                        break;
-               LOG_DEBUG("DEBUGMODULE: No memory access in progress!");
-               return ERROR_JTAG_DEVICE_ERROR;
+
+               if ( (timeout = timeval_ms()-then) > 1000 )
+               {
+                       LOG_DEBUG("DEBUGMODULE: No memory access in progress!");
+                       return ERROR_JTAG_DEVICE_ERROR;
+               }
        }
 
        *ctrl = ejtag_ctrl;
@@ -168,14 +190,13 @@ static int mips32_pracc_exec_read(struct mips32_pracc_context *ctx, uint32_t add
 
        /* Send the data out */
        mips_ejtag_set_instr(ctx->ejtag_info, EJTAG_INST_DATA);
-       mips_ejtag_drscan_32(ctx->ejtag_info, &data);
+       mips_ejtag_drscan_32_out(ctx->ejtag_info, data);
 
        /* Clear the access pending bit (let the processor eat!) */
        ejtag_ctrl = ejtag_info->ejtag_ctrl & ~EJTAG_CTRL_PRACC;
        mips_ejtag_set_instr(ctx->ejtag_info, EJTAG_INST_CONTROL);
-       mips_ejtag_drscan_32(ctx->ejtag_info, &ejtag_ctrl);
+       mips_ejtag_drscan_32_out(ctx->ejtag_info, ejtag_ctrl);
 
-       jtag_add_clocks(5);
        return jtag_execute_queue();
 }
 
@@ -184,17 +205,21 @@ static int mips32_pracc_exec_write(struct mips32_pracc_context *ctx, uint32_t ad
        uint32_t ejtag_ctrl,data;
        int offset;
        struct mips_ejtag *ejtag_info = ctx->ejtag_info;
+       int retval;
 
        mips_ejtag_set_instr(ctx->ejtag_info, EJTAG_INST_DATA);
-       mips_ejtag_drscan_32(ctx->ejtag_info, &data);
+       retval = mips_ejtag_drscan_32(ctx->ejtag_info, &data);
+       if (retval != ERROR_OK)
+               return retval;
 
        /* Clear access pending bit */
        ejtag_ctrl = ejtag_info->ejtag_ctrl & ~EJTAG_CTRL_PRACC;
        mips_ejtag_set_instr(ctx->ejtag_info, EJTAG_INST_CONTROL);
-       mips_ejtag_drscan_32(ctx->ejtag_info, &ejtag_ctrl);
+       mips_ejtag_drscan_32_out(ctx->ejtag_info, ejtag_ctrl);
 
-       jtag_add_clocks(5);
-       return jtag_execute_queue();
+       retval = jtag_execute_queue();
+       if (retval != ERROR_OK)
+               return retval;
 
        if ((address >= MIPS32_PRACC_PARAM_IN)
                && (address <= MIPS32_PRACC_PARAM_IN + ctx->num_iparam * 4))
@@ -247,7 +272,9 @@ int mips32_pracc_exec(struct mips_ejtag *ejtag_info, int code_len, const uint32_
 
                address = data = 0;
                mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS);
-               mips_ejtag_drscan_32(ejtag_info, &address);
+               retval = mips_ejtag_drscan_32(ejtag_info, &address);
+               if (retval != ERROR_OK)
+                       return retval;
 
                /* Check for read or write */
                if (ejtag_ctrl & EJTAG_CTRL_PRNW)
@@ -448,11 +475,8 @@ static int mips32_pracc_read_mem16(struct mips_ejtag *ejtag_info, uint32_t addr,
 
        int retval = ERROR_OK;
        int blocksize;
-       int bytesread;
        uint32_t param_in[2];
 
-       bytesread = 0;
-
        //while (count > 0)
        {
                blocksize = count;
@@ -467,7 +491,6 @@ static int mips32_pracc_read_mem16(struct mips_ejtag *ejtag_info, uint32_t addr,
 
 //             count -= blocksize;
 //             addr += blocksize;
-//             bytesread += blocksize;
        }
 
        for (i = 0; i < count; i++)
@@ -525,11 +548,8 @@ static int mips32_pracc_read_mem8(struct mips_ejtag *ejtag_info, uint32_t addr,
 
        int retval = ERROR_OK;
        int blocksize;
-       int bytesread;
        uint32_t param_in[2];
 
-       bytesread = 0;
-
 //     while (count > 0)
        {
                blocksize = count;
@@ -544,7 +564,6 @@ static int mips32_pracc_read_mem8(struct mips_ejtag *ejtag_info, uint32_t addr,
 
 //             count -= blocksize;
 //             addr += blocksize;
-//             bytesread += blocksize;
        }
 
        for (i = 0; i < count; i++)
@@ -557,22 +576,338 @@ static int mips32_pracc_read_mem8(struct mips_ejtag *ejtag_info, uint32_t addr,
        return retval;
 }
 
+int mips32_cp0_read(struct mips_ejtag *ejtag_info, uint32_t *val, uint32_t cp0_reg, uint32_t cp0_sel)
+{
+       /**
+        * Do not make this code static, but regenerate it every time,
+        * as 5th element has to be changed to add parameters
+        */
+       uint32_t code[] = {
+                                                                                                                       /* start: */
+               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(8,0,15),                                                                      /* sw $8,($15) */
+               MIPS32_SW(9,0,15),                                                                      /* sw $9,($15) */
+
+               /* 5 */ MIPS32_MFC0(8,0,0),                                                     /* move COP0 [cp0_reg select] to $8 */
+
+               MIPS32_LUI(9,UPPER16(MIPS32_PRACC_PARAM_OUT)),          /* $11 = MIPS32_PRACC_PARAM_OUT */
+               MIPS32_ORI(9,9,LOWER16(MIPS32_PRACC_PARAM_OUT)),
+               MIPS32_SW(8,0,9),                                                                       /* sw $8,0($9) */
+
+               MIPS32_LW(9,0,15),                                                                      /* lw $9,($15) */
+               MIPS32_LW(8,0,15),                                                                      /* lw $8,($15) */
+               MIPS32_B(NEG16(12)),                                                            /* b start */
+               MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
+       };
+
+       /**
+        * Note that our input parametes cp0_reg and cp0_sel
+        * are numbers (not gprs) which make part of mfc0 instruction opcode.
+        *
+        * These are not fix, but can be different for each mips32_cp0_read() function call,
+        * and that is why we must insert them directly into opcode,
+        * i.e. we can not pass it on EJTAG microprogram stack (via param_in),
+        * and put them into the gprs later from MIPS32_PRACC_STACK
+        * because mfc0 do not use gpr as a parameter for the cp0_reg and select part,
+        * but plain (immediate) number.
+        *
+        * MIPS32_MTC0 is implemented via MIPS32_R_INST macro.
+        * In order to insert our parameters, we must change rd and funct fields.
+        */
+       code[5] |= (cp0_reg << 11) | cp0_sel;  /* change rd and funct of MIPS32_R_INST macro */
+
+       /* TODO remove array */
+       uint32_t *param_out = val;
+       int retval;
+
+       retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 0, NULL, 1, param_out, 1);
+
+       return retval;
+}
+
+int mips32_cp0_write(struct mips_ejtag *ejtag_info,
+                                                                                       uint32_t val, uint32_t cp0_reg, uint32_t cp0_sel)
+{
+       uint32_t code[] = {
+                                                                                                                       /* start: */
+               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(8,0,15),                                                                      /* sw $8,($15) */
+               MIPS32_SW(9,0,15),                                                                      /* sw $9,($15) */
+
+               MIPS32_LUI(8,UPPER16(MIPS32_PRACC_PARAM_IN)),           /* $8 = MIPS32_PRACC_PARAM_IN */
+               MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_PARAM_IN)),
+               MIPS32_LW(9,0,8),                                                                       /* Load write val to $9 */
+
+               /* 8 */ MIPS32_MTC0(9,0,0),                                                     /* move $9 to COP0 [cp0_reg select] */
+
+               MIPS32_LW(9,0,15),                                                                      /* lw $9,($15) */
+               MIPS32_LW(8,0,15),                                                                      /* lw $8,($15) */
+               MIPS32_B(NEG16(12)),                                                            /* b start */
+               MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
+       };
+
+       /**
+        * Note that MIPS32_MTC0 macro is implemented via MIPS32_R_INST macro.
+        * In order to insert our parameters, we must change rd and funct fields.
+        */
+       code[8] |= (cp0_reg << 11) | cp0_sel;  /* change rd and funct fields of MIPS32_R_INST macro */
+
+       /* TODO remove array */
+       uint32_t *param_in = malloc(1 * sizeof(uint32_t));
+       int retval;
+       param_in[0] = val;
+
+       retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 1, param_in, 0, NULL, 1);
+
+       free(param_in);
+
+       return retval;
+}
+
+/**
+ * \b mips32_pracc_sync_cache
+ *
+ * Synchronize Caches to Make Instruction Writes Effective
+ * (ref. doc. MIPS32 Architecture For Programmers Volume II: The MIPS32 Instruction Set,
+ *  Document Number: MD00086, Revision 2.00, June 9, 2003)
+ *
+ * When the instruction stream is written, the SYNCI instruction should be used
+ * in conjunction with other instructions to make the newly-written instructions effective.
+ *
+ * Explanation :
+ * A program that loads another program into memory is actually writing the D- side cache.
+ * The instructions it has loaded can't be executed until they reach the I-cache.
+ *
+ * After the instructions have been written, the loader should arrange
+ * to write back any containing D-cache line and invalidate any locations
+ * already in the I-cache.
+ *
+ * You can do that with cache instructions, but those instructions are only available in kernel mode,
+ * and a loader writing instructions for the use of its own process need not be privileged software.
+ *
+ * In the latest MIPS32/64 CPUs, MIPS provides the synci instruction,
+ * which does the whole job for a cache-line-sized chunk of the memory you just loaded:
+ * That is, it arranges a D-cache write-back and an I-cache invalidate.
+ *
+ * To employ synci at user level, you need to know the size of a cache line,
+ * and that can be obtained with a rdhwr SYNCI_Step
+ * from one of the standard “hardware registers”.
+ */
+static int mips32_pracc_sync_cache(struct mips_ejtag *ejtag_info,
+                                                                                       uint32_t start_addr, uint32_t end_addr)
+{
+       static const uint32_t code[] = {
+                                                                                                                       /* start: */
+               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(8,0,15),                                                                      /* sw $8,($15) */
+               MIPS32_SW(9,0,15),                                                                      /* sw $9,($15) */
+               MIPS32_SW(10,0,15),                                                                     /* sw $10,($15) */
+               MIPS32_SW(11,0,15),                                                                     /* sw $11,($15) */
+
+               MIPS32_LUI(8,UPPER16(MIPS32_PRACC_PARAM_IN)),           /* $8 = MIPS32_PRACC_PARAM_IN */
+               MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_PARAM_IN)),
+               MIPS32_LW(9,0,8),                                                                       /* Load write start_addr to $9 */
+               MIPS32_LW(10,4,8),                                                                      /* Load write end_addr to $10 */
+
+               MIPS32_RDHWR(11, MIPS32_SYNCI_STEP),                            /* $11 = MIPS32_SYNCI_STEP */
+               MIPS32_BEQ(11,0,6),                                                                     /* beq $11, $0, end */
+               MIPS32_NOP,
+                                                                                                                       /* synci_loop : */
+               MIPS32_SYNCI(0,9),                                                                      /* synci 0($9) */
+               MIPS32_SLTU(8,10,9),                                                            /* sltu $8, $10, $9  # $8 = $10 < $9 ? 1 : 0 */
+               MIPS32_BNE(8,0,NEG16(3)),                                                       /* bne $8, $0, synci_loop */
+               MIPS32_ADDU(9, 9, 11),                                                          /* $9 += MIPS32_SYNCI_STEP */
+               MIPS32_SYNC,
+                                                                                                                       /* end: */
+               MIPS32_LW(11,0,15),                                                                     /* lw $11,($15) */
+               MIPS32_LW(10,0,15),                                                                     /* lw $10,($15) */
+               MIPS32_LW(9,0,15),                                                                      /* lw $9,($15) */
+               MIPS32_LW(8,0,15),                                                                      /* lw $8,($15) */
+               MIPS32_B(NEG16(24)),                                                            /* b start */
+               MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
+       };
+
+       /* TODO remove array */
+       uint32_t *param_in = malloc(2 * sizeof(uint32_t));
+       int retval;
+       param_in[0] = start_addr;
+       param_in[1] = end_addr;
+
+       retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 2, param_in, 0, NULL, 1);
+
+       free(param_in);
+
+       return retval;
+}
+
+/**
+ * \b mips32_pracc_clean_invalidate_cache
+ *
+ * Writeback D$ and Invalidate I$
+ * so that the instructions written can be visible to CPU
+ */
+static int mips32_pracc_clean_invalidate_cache(struct mips_ejtag *ejtag_info,
+                                                                                                       uint32_t start_addr, uint32_t end_addr)
+{
+       static const uint32_t code[] = {
+                                                                                                                       /* start: */
+               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(8,0,15),                                                                      /* sw $8,($15) */
+               MIPS32_SW(9,0,15),                                                                      /* sw $9,($15) */
+               MIPS32_SW(10,0,15),                                                                     /* sw $10,($15) */
+               MIPS32_SW(11,0,15),                                                                     /* sw $11,($15) */
+
+               MIPS32_LUI(8,UPPER16(MIPS32_PRACC_PARAM_IN)),           /* $8 = MIPS32_PRACC_PARAM_IN */
+               MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_PARAM_IN)),
+               MIPS32_LW(9,0,8),                                                                       /* Load write start_addr to $9 */
+               MIPS32_LW(10,4,8),                                                                      /* Load write end_addr to $10 */
+               MIPS32_LW(11,8,8),                                                                      /* Load write clsiz to $11 */
+
+                                                                                                                       /* cache_loop: */
+               MIPS32_SLTU(8,10,9),                                                            /* sltu $8, $10, $9  :  $8 <- $10 < $9 ? */
+               MIPS32_BGTZ(8,6),                                                                       /* bgtz $8, end */
+               MIPS32_NOP,
+
+               MIPS32_CACHE(MIPS32_CACHE_D_HIT_WRITEBACK,0,9),         /* cache Hit_Writeback_D, 0($9) */
+               MIPS32_CACHE(MIPS32_CACHE_I_HIT_INVALIDATE,0,9),        /* cache Hit_Invalidate_I, 0($9) */
+
+               MIPS32_ADDU(9,9,11),                                                            /* $9 += $11 */
+
+               MIPS32_B(NEG16(7)),                                                                     /* b cache_loop */
+               MIPS32_NOP,
+                                                                                                                       /* end: */
+               MIPS32_LW(11,0,15),                                                                     /* lw $11,($15) */
+               MIPS32_LW(10,0,15),                                                                     /* lw $10,($15) */
+               MIPS32_LW(9,0,15),                                                                      /* lw $9,($15) */
+               MIPS32_LW(8,0,15),                                                                      /* lw $8,($15) */
+               MIPS32_B(NEG16(25)),                                                            /* b start */
+               MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
+       };
+
+       /**
+        * Find cache line size in bytes
+        */
+       uint32_t conf;
+       uint32_t dl, clsiz;
+
+       mips32_cp0_read(ejtag_info, &conf, 16, 1);
+       dl = (conf & MIPS32_CONFIG1_DL_MASK) >> MIPS32_CONFIG1_DL_SHIFT;
+
+       /* dl encoding : dl=1 => 4 bytes, dl=2 => 8 bytes, etc... */
+       clsiz = 0x2 << dl;
+
+       /* TODO remove array */
+       uint32_t *param_in = malloc(3 * sizeof(uint32_t));
+       int retval;
+       param_in[0] = start_addr;
+       param_in[1] = end_addr;
+       param_in[2] = clsiz;
+
+       retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 3, param_in, 0, NULL, 1);
+
+       free(param_in);
+
+       return retval;
+}
+
+
 int mips32_pracc_write_mem(struct mips_ejtag *ejtag_info, uint32_t addr, int size, int count, void *buf)
 {
+       int retval;
+
        switch (size)
        {
                case 1:
-                       return mips32_pracc_write_mem8(ejtag_info, addr, count, (uint8_t*)buf);
+                       retval = mips32_pracc_write_mem8(ejtag_info, addr, count, (uint8_t*)buf);
+                       break;
                case 2:
-                       return mips32_pracc_write_mem16(ejtag_info, addr, count,(uint16_t*)buf);
+                       retval = mips32_pracc_write_mem16(ejtag_info, addr, count,(uint16_t*)buf);
+                       break;
                case 4:
                        if (count == 1)
-                               return mips32_pracc_write_u32(ejtag_info, addr, (uint32_t*)buf);
+                       {
+                               retval = mips32_pracc_write_u32(ejtag_info, addr, (uint32_t*)buf);
+                       }
                        else
-                               return mips32_pracc_write_mem32(ejtag_info, addr, count, (uint32_t*)buf);
+                       {
+                               retval = mips32_pracc_write_mem32(ejtag_info, addr, count, (uint32_t*)buf);
+                       }
+                       break;
+               default:
+                       retval = ERROR_FAIL;
        }
 
-       return ERROR_OK;
+       /**
+        * If we are in the cachable regoion and cache is activated,
+        * we must clean D$ + invalidate I$ after we did the write,
+        * so that changes do not continue to live only in D$, but to be
+        * replicated in I$ also (maybe we wrote the istructions)
+        */
+       uint32_t conf = 0;
+       int cached = 0;
+
+       mips32_cp0_read(ejtag_info, &conf, 16, 0);
+
+       switch (KSEGX(addr))
+       {
+               case KUSEG:
+                       cached = (conf & MIPS32_CONFIG0_KU_MASK) >> MIPS32_CONFIG0_KU_SHIFT;
+                       break;
+               case KSEG0 :
+                       cached = (conf & MIPS32_CONFIG0_K0_MASK) >> MIPS32_CONFIG0_K0_SHIFT;
+                       break;
+               case KSEG1:
+                       /* uncachable segment - nothing to do */
+                       break;
+               case KSEG2:
+               case KSEG3:
+                       cached = (conf & MIPS32_CONFIG0_K23_MASK) >> MIPS32_CONFIG0_K23_SHIFT;
+                       break;
+               default:
+                       /* what ? */
+                       break;
+       }
+
+       /**
+        * Check cachablitiy bits coherency algorithm -
+        * is the region cacheable or uncached.
+        * If cacheable we have to synchronize the cache
+        */
+       if (cached == 0x3)
+       {
+               uint32_t start_addr, end_addr;
+               uint32_t rel;
+
+               start_addr = addr;
+               end_addr = addr + count * size;
+
+               /** select cache synchronisation mechanism based on Architecture Release */
+               rel = (conf & MIPS32_CONFIG0_AR_MASK) >> MIPS32_CONFIG0_AR_SHIFT;
+               switch (rel)
+               {
+                       case MIPS32_ARCH_REL1 :
+                               /* MIPS32/64 Release 1 - we must use cache instruction */
+                               mips32_pracc_clean_invalidate_cache(ejtag_info, start_addr, end_addr);
+                               break;
+                       case MIPS32_ARCH_REL2 :
+                               /* MIPS32/64 Release 2 - we can use synci instruction */
+                               mips32_pracc_sync_cache(ejtag_info, start_addr, end_addr);
+                               break;
+                       default :
+                               /* what ? */
+                               break;
+               }
+       }
+
+       return retval;
 }
 
 static int mips32_pracc_write_mem32(struct mips_ejtag *ejtag_info, uint32_t addr, int count, uint32_t *buf)
@@ -1001,12 +1336,12 @@ int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_are
                        return retval;
 
                mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA);
-               mips_ejtag_drscan_32(ejtag_info, &jmp_code[i]);
+               mips_ejtag_drscan_32_out(ejtag_info, jmp_code[i]);
 
                /* Clear the access pending bit (let the processor eat!) */
                ejtag_ctrl = ejtag_info->ejtag_ctrl & ~EJTAG_CTRL_PRACC;
                mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
-               mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
+               mips_ejtag_drscan_32_out(ejtag_info, ejtag_ctrl);
        }
 
        if ((retval = wait_for_pracc_rw(ejtag_info, &ejtag_ctrl)) != ERROR_OK)
@@ -1015,11 +1350,17 @@ int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_are
        /* next fetch to dmseg should be in FASTDATA_AREA, check */
        address = 0;
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS);
-       mips_ejtag_drscan_32(ejtag_info, &address);
+       retval = mips_ejtag_drscan_32(ejtag_info, &address);
+       if (retval != ERROR_OK)
+               return retval;
 
        if (address != MIPS32_PRACC_FASTDATA_AREA)
                return ERROR_FAIL;
 
+       /* wait PrAcc pending bit for FASTDATA write */
+       if ((retval = wait_for_pracc_rw(ejtag_info, &ejtag_ctrl)) != ERROR_OK)
+               return retval;
+
        /* Send the load start address */
        val = addr;
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_FASTDATA);
@@ -1027,12 +1368,10 @@ int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_are
 
        /* Send the load end address */
        val = addr + (count - 1) * 4;
-       mips_ejtag_set_instr(ejtag_info, EJTAG_INST_FASTDATA);
        mips_ejtag_fastdata_scan(ejtag_info, 1, &val);
 
        for (i = 0; i < count; i++)
        {
-               /* Send the data out using fastdata (clears the access pending bit) */
                if ((retval = mips_ejtag_fastdata_scan(ejtag_info, write_t, buf++)) != ERROR_OK)
                        return retval;
        }
@@ -1048,7 +1387,9 @@ int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_are
 
        address = 0;
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS);
-       mips_ejtag_drscan_32(ejtag_info, &address);
+       retval = mips_ejtag_drscan_32(ejtag_info, &address);
+       if (retval != ERROR_OK)
+               return retval;
 
        if (address != MIPS32_PRACC_TEXT)
                LOG_ERROR("mini program did not return to start");