MIPS: fastdata bulk write fallback
[fw/openocd] / src / target / mips32_pracc.c
index 604d34edbf2524d9183b69740fa6d85f00f1438e..ac1d1b39860504921fd9122616a037016b53ad37 100644 (file)
@@ -4,6 +4,8 @@
  *                                                                         *
  *   Copyright (C) 2008 by David T.L. Wong                                 *
  *                                                                         *
+ *   Copyright (C) 2009 by David N. Claffey <dnclaffey@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     *
@@ -31,7 +33,6 @@ instruction after a branch instruction (one delay slot).
 
 For example:
 
-
     LW $2, ($5 +10)
     B foo
     LW $1, ($2 +100)
@@ -69,7 +70,6 @@ OpenOCD is used as a flash programmer or as a debug tool.
 Nico Coesel
 */
 
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -128,7 +128,7 @@ static int mips32_pracc_exec_read(struct mips32_pracc_context *ctx, uint32_t add
                data = ctx->local_oparam[offset];
        }
        else if ((address >= MIPS32_PRACC_TEXT)
-               && (address <= MIPS32_PRACC_TEXT + ctx->code_len*4))
+               && (address <= MIPS32_PRACC_TEXT + ctx->code_len * 4))
        {
                offset = (address - MIPS32_PRACC_TEXT) / 4;
                data = ctx->code[offset];
@@ -144,7 +144,7 @@ static int mips32_pracc_exec_read(struct mips32_pracc_context *ctx, uint32_t add
                 * to start of debug vector */
 
                data = 0;
-               LOG_ERROR("Error reading unexpected address %8.8" PRIx32 "", address);
+               LOG_ERROR("Error reading unexpected address 0x%8.8" PRIx32 "", address);
                return ERROR_JTAG_DEVICE_ERROR;
        }
 
@@ -153,7 +153,6 @@ static int mips32_pracc_exec_read(struct mips32_pracc_context *ctx, uint32_t add
        mips_ejtag_drscan_32(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, NULL);
        mips_ejtag_drscan_32(ctx->ejtag_info, &ejtag_ctrl);
@@ -161,7 +160,6 @@ static int mips32_pracc_exec_read(struct mips32_pracc_context *ctx, uint32_t add
        jtag_add_clocks(5);
        jtag_execute_queue();
 
-
        return ERROR_OK;
 }
 
@@ -201,7 +199,7 @@ static int mips32_pracc_exec_write(struct mips32_pracc_context *ctx, uint32_t ad
        }
        else
        {
-               LOG_ERROR("Error writing unexpected address %8.8" PRIx32 "", address);
+               LOG_ERROR("Error writing unexpected address 0x%8.8" PRIx32 "", address);
                return ERROR_JTAG_DEVICE_ERROR;
        }
 
@@ -234,8 +232,6 @@ int mips32_pracc_exec(struct mips_ejtag *ejtag_info, int code_len, const uint32_
                mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);
                mips_ejtag_drscan_32(ejtag_info, &address);
 
-//             printf("Adres: %.8x\n", address);
-
                /* Check for read or write */
                if (ejtag_ctrl & EJTAG_CTRL_PRNW)
                {
@@ -254,7 +250,6 @@ int mips32_pracc_exec(struct mips_ejtag *ejtag_info, int code_len, const uint32_
 
                        if ((retval = mips32_pracc_exec_read(&ctx, address)) != ERROR_OK)
                                return retval;
-
                }
 
                if (cycle == 0)
@@ -306,9 +301,8 @@ int mips32_pracc_read_mem32(struct mips_ejtag *ejtag_info, uint32_t addr, int co
                MIPS32_LW(10,4,8),                                                                      /* $10 = mem[$8 + 4]; read count */
                MIPS32_LUI(11,UPPER16(MIPS32_PRACC_PARAM_OUT)),         /* $11 = MIPS32_PRACC_PARAM_OUT */
                MIPS32_ORI(11,11,LOWER16(MIPS32_PRACC_PARAM_OUT)),
-               MIPS32_NOP,
                                                                                                                        /* loop: */
-               MIPS32_BEQ(0,10,9),                                                                     /* beq 0, $10, end */
+               MIPS32_BEQ(0,10,8),                                                                     /* beq 0, $10, end */
                MIPS32_NOP,
 
                MIPS32_LW(8,0,9),                                                                       /* lw $8,0($9), Load $8 with the word @mem[$9] */
@@ -318,18 +312,15 @@ int mips32_pracc_read_mem32(struct mips_ejtag *ejtag_info, uint32_t addr, int co
                MIPS32_ADDI(9,9,4),                                                             /* $1 += 4 */
                MIPS32_ADDI(11,11,4),                                                           /* $11 += 4 */
 
-               MIPS32_NOP,
-               MIPS32_B(NEG16(9)),                                                                     /* b loop */
+               MIPS32_B(NEG16(8)),                                                                     /* b 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(27)),                                                            /* b start */
                MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(31)),                                                            /* b start */
-               MIPS32_NOP,
        };
 
        int retval = ERROR_OK;
@@ -371,15 +362,14 @@ int mips32_pracc_read_u32(struct mips_ejtag *ejtag_info, uint32_t addr, uint32_t
                MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)),
                MIPS32_SW(8,0,15),                                                                      /* sw $8,($15) */
 
-               MIPS32_LW(8,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN), 15),  //load R8 @ param_in[0] = address
+               MIPS32_LW(8,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN),15), /* load R8 @ param_in[0] = address */
 
                MIPS32_LW(8,0,8),                                                                       /* lw $8,0($8), Load $8 with the word @mem[$8] */
-               MIPS32_SW(8,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_OUT),15),                                                                       /* sw $8,0($9) */
+               MIPS32_SW(8,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_OUT),15), /* store R8 @ param_out[0] */
 
                MIPS32_LW(8,0,15),                                                                      /* lw $8,($15) */
-               MIPS32_B(NEG16(9)),     //was 17                                                        /* b start */
-               MIPS32_MFC0(15,31,0),   //this instruction will be executed (MIPS executes instruction after jump)                                                      /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
+               MIPS32_B(NEG16(9)),                                                                     /* b start */
+               MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
        };
 
        int retval = ERROR_OK;
@@ -388,7 +378,7 @@ int mips32_pracc_read_u32(struct mips_ejtag *ejtag_info, uint32_t addr, uint32_t
        param_in[0] = addr;
 
        if ((retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code,
-               ARRAY_SIZE(param_in), param_in, sizeof(uint32_t), buf, 1)) != ERROR_OK)
+               ARRAY_SIZE(param_in), param_in, 1, buf, 1)) != ERROR_OK)
        {
                return retval;
        }
@@ -414,9 +404,8 @@ int mips32_pracc_read_mem16(struct mips_ejtag *ejtag_info, uint32_t addr, int co
                MIPS32_LW(10,4,8),                                                                      /* $10 = mem[$8 + 4]; read count */
                MIPS32_LUI(11,UPPER16(MIPS32_PRACC_PARAM_OUT)),         /* $11 = MIPS32_PRACC_PARAM_OUT */
                MIPS32_ORI(11,11,LOWER16(MIPS32_PRACC_PARAM_OUT)),
-               MIPS32_NOP,
                                                                                                                        /* loop: */
-               MIPS32_BEQ(0,10,9),                                                             /* beq 0, $10, end */
+               MIPS32_BEQ(0,10,8),                                                             /* beq 0, $10, end */
                MIPS32_NOP,
 
                MIPS32_LHU(8,0,9),                                                                      /* lw $8,0($9), Load $8 with the halfword @mem[$9] */
@@ -425,21 +414,18 @@ int mips32_pracc_read_mem16(struct mips_ejtag *ejtag_info, uint32_t addr, int co
                MIPS32_ADDI(10,10,NEG16(1)),                                            /* $10-- */
                MIPS32_ADDI(9,9,2),                                                             /* $9 += 2 */
                MIPS32_ADDI(11,11,4),                                                           /* $11 += 4 */
+               MIPS32_B(NEG16(8)),                                                                     /* b loop */
                MIPS32_NOP,
-               MIPS32_B(NEG16(9)),                                                                     /* b 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_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(31)),                                                            /* b start */
-               MIPS32_NOP,
+               MIPS32_B(NEG16(27)),                                                            /* b start */
+               MIPS32_MFC0(15,30,0),                                                           /* move COP0 DeSave to $15 */
        };
 
-//     /* TODO remove array */
+       /* TODO remove array */
        uint32_t *param_out = malloc(count * sizeof(uint32_t));
        int i;
 
@@ -495,9 +481,8 @@ int mips32_pracc_read_mem8(struct mips_ejtag *ejtag_info, uint32_t addr, int cou
                MIPS32_LW(10,4,8),                                                                      /* $10 = mem[$8 + 4]; read count */
                MIPS32_LUI(11,UPPER16(MIPS32_PRACC_PARAM_OUT)),         /* $11 = MIPS32_PRACC_PARAM_OUT */
                MIPS32_ORI(11,11,LOWER16(MIPS32_PRACC_PARAM_OUT)),
-               MIPS32_NOP,
                                                                                                                        /* loop: */
-               MIPS32_BEQ(0,10,9),                                                             /* beq 0, $10, end */
+               MIPS32_BEQ(0,10,8),                                                             /* beq 0, $10, end */
                MIPS32_NOP,
 
                MIPS32_LBU(8,0,9),                                                                      /* lw $8,0($9), Load t4 with the byte @mem[t1] */
@@ -506,21 +491,18 @@ int mips32_pracc_read_mem8(struct mips_ejtag *ejtag_info, uint32_t addr, int cou
                MIPS32_ADDI(10,10,NEG16(1)),                                            /* $10-- */
                MIPS32_ADDI(9,9,1),                                                             /* $9 += 1 */
                MIPS32_ADDI(11,11,4),                                                           /* $11 += 4 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(9)),                                                                     /* b loop */
+               MIPS32_B(NEG16(8)),                                                                     /* b 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(27)),                                                            /* b start */
                MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(31)),                                                            /* b start */
-               MIPS32_NOP,
        };
 
-//     /* TODO remove array */
+       /* TODO remove array */
        uint32_t *param_out = malloc(count * sizeof(uint32_t));
        int i;
 
@@ -578,8 +560,6 @@ int mips32_pracc_write_mem(struct mips_ejtag *ejtag_info, uint32_t addr, int siz
 
 int mips32_pracc_write_mem32(struct mips_ejtag *ejtag_info, uint32_t addr, int count, uint32_t *buf)
 {
-
-//NC: use destination pointer as loop counter (last address is in $10)
        static const uint32_t code[] = {
                                                                                                                        /* start: */
                MIPS32_MTC0(15,31,0),                                                           /* move $15 to COP0 DeSave */
@@ -590,32 +570,32 @@ int mips32_pracc_write_mem32(struct mips_ejtag *ejtag_info, uint32_t addr, int c
                MIPS32_SW(10,0,15),                                                             /* sw $10,($15) */
                MIPS32_SW(11,0,15),                                                             /* sw $11,($15) */
 
-               MIPS32_ADDI(8,15,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN)),  //$8= MIPS32_PRACC_PARAM_IN
+               MIPS32_ADDI(8,15,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN)),  /* $8= MIPS32_PRACC_PARAM_IN */
                MIPS32_LW(9,0,8),                                                                       /* Load write addr to $9 */
-               MIPS32_LW(10,4,8),      //last address                                                                  /* Load write count to $10 */
-               MIPS32_ADDI(8,8,8),     // $8 += 8 beginning of data
+               MIPS32_LW(10,4,8),                                                                      /* Load write count to $10 */
+               MIPS32_ADDI(8,8,8),                                                                     /* $8 += 8 beginning of data */
 
-//loop:
+                                                                                                                       /* loop: */
                MIPS32_LW(11,0,8),                                                                      /* lw $11,0($8), Load $11 with the word @mem[$8] */
                MIPS32_SW(11,0,9),                                                                      /* sw $11,0($9) */
 
                MIPS32_ADDI(9,9,4),                                                             /* $9 += 4 */
-               MIPS32_BNE(10,9,NEG16(4)),  //was 9 BNE $10, 9, loop                                                                    /* b loop */
-               MIPS32_ADDI(8,8,4),  //this instruction is part of the loop (one delay slot)!   /* $8 += 4 */
+               MIPS32_BNE(10,9,NEG16(4)),                                                      /* bne $10, $9, loop */
+               MIPS32_ADDI(8,8,4),                                                                     /* $8 += 4 */
+
                                                                                                                        /* 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(21)),     //was 30                                                       /* b start */
+               MIPS32_B(NEG16(21)),                                                            /* b start */
                MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
-               MIPS32_NOP, //this one will not be executed
        };
 
        /* TODO remove array */
        uint32_t *param_in = malloc((count + 2) * sizeof(uint32_t));
        param_in[0] = addr;
-       param_in[1] = addr + count * sizeof(uint32_t);  //last address
+       param_in[1] = addr + (count * sizeof(uint32_t));        /* last address */
 
        memcpy(&param_in[2], buf, count * sizeof(uint32_t));
 
@@ -637,16 +617,15 @@ int mips32_pracc_write_u32(struct mips_ejtag *ejtag_info, uint32_t addr, uint32_
                MIPS32_SW(8,0,15),                                                                      /* sw $8,($15) */
                MIPS32_SW(9,0,15),                                                                      /* sw $9,($15) */
 
-               MIPS32_LW(8,NEG16((MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN)-4), 15),  //load R8 @ param_in[1] = data
-               MIPS32_LW(9,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN), 15),  //load R9 @ param_in[0] = address
+               MIPS32_LW(8,NEG16((MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN)-4), 15),   /* load R8 @ param_in[1] = data */
+               MIPS32_LW(9,NEG16(MIPS32_PRACC_STACK-MIPS32_PRACC_PARAM_IN), 15),               /* load R9 @ param_in[0] = address */
 
                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(11)),                                                            /* b start */
-               MIPS32_MFC0(15,31,0),                                                   /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
+               MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
        };
 
        /* TODO remove array */
@@ -655,7 +634,7 @@ int mips32_pracc_write_u32(struct mips_ejtag *ejtag_info, uint32_t addr, uint32_
        param_in[1] = *buf;
 
        mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               ARRAY_SIZE(param_in),param_in, 0, NULL, 1);
+               ARRAY_SIZE(param_in), param_in, 0, NULL, 1);
 
        return ERROR_OK;
 }
@@ -677,9 +656,8 @@ int mips32_pracc_write_mem16(struct mips_ejtag *ejtag_info, uint32_t addr, int c
                MIPS32_LW(9,0,8),                                                                       /* Load write addr to $9 */
                MIPS32_LW(10,4,8),                                                                      /* Load write count to $10 */
                MIPS32_ADDI(8,8,8),                                                             /* $8 += 8 */
-               MIPS32_NOP,
                                                                                                                        /* loop: */
-               MIPS32_BEQ(0,10,9),                                                                     /* beq $0, $10, end */
+               MIPS32_BEQ(0,10,8),                                                                     /* beq $0, $10, end */
                MIPS32_NOP,
 
                MIPS32_LW(11,0,8),                                                                      /* lw $11,0($8), Load $11 with the word @mem[$8] */
@@ -689,18 +667,15 @@ int mips32_pracc_write_mem16(struct mips_ejtag *ejtag_info, uint32_t addr, int c
                MIPS32_ADDI(9,9,2),                                                             /* $9 += 2 */
                MIPS32_ADDI(8,8,4),                                                             /* $8 += 4 */
 
-               MIPS32_NOP,
-               MIPS32_B(NEG16(9)),                                                                     /* b loop */
+               MIPS32_B(NEG16(8)),                                                                     /* b 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(26)),                                                            /* b start */
                MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(30)),                                                            /* b start */
-               MIPS32_NOP,
        };
 
        /* TODO remove array */
@@ -739,9 +714,8 @@ int mips32_pracc_write_mem8(struct mips_ejtag *ejtag_info, uint32_t addr, int co
                MIPS32_LW(9,0,8),                                                                       /* Load write addr to $9 */
                MIPS32_LW(10,4,8),                                                                      /* Load write count to $10 */
                MIPS32_ADDI(8,8,8),                                                             /* $8 += 8 */
-               MIPS32_NOP,
                                                                                                                        /* loop: */
-               MIPS32_BEQ(0,10,9),                                                                     /* beq $0, $10, end */
+               MIPS32_BEQ(0,10,8),                                                                     /* beq $0, $10, end */
                MIPS32_NOP,
 
                MIPS32_LW(11,0,8),                                                                      /* lw $11,0($8), Load $11 with the word @mem[$8] */
@@ -751,18 +725,15 @@ int mips32_pracc_write_mem8(struct mips_ejtag *ejtag_info, uint32_t addr, int co
                MIPS32_ADDI(9,9,1),                                                             /* $9 += 1 */
                MIPS32_ADDI(8,8,4),                                                             /* $8 += 4 */
 
-               MIPS32_NOP,
-               MIPS32_B(NEG16(9)),                                                                     /* b loop */
+               MIPS32_B(NEG16(8)),                                                                     /* b 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(26)),                                                            /* b start */
                MIPS32_MFC0(15,31,0),                                                           /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(30)),                                                            /* b start */
-               MIPS32_NOP,
        };
 
        /* TODO remove array */
@@ -778,7 +749,7 @@ int mips32_pracc_write_mem8(struct mips_ejtag *ejtag_info, uint32_t addr, int co
        }
 
        retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               count +2, param_in, 0, NULL, 1);
+               count + 2, param_in, 0, NULL, 1);
 
        free(param_in);
 
@@ -843,16 +814,14 @@ int mips32_pracc_write_regs(struct mips_ejtag *ejtag_info, uint32_t *regs)
 
                MIPS32_LW(2,2*4,1),                                                     /* lw $2,2*4($1) */
                MIPS32_LW(1,0,15),                                                              /* lw $1,($15) */
+               MIPS32_B(NEG16(53)),                                                    /* b start */
                MIPS32_MFC0(15,31,0),                                                   /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(55)),                                                    /* b start */
-               MIPS32_NOP,
        };
 
        int retval;
 
        retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               38, regs, 0, NULL, 1);
+                       MIPS32NUMCOREREGS, regs, 0, NULL, 1);
 
        return retval;
 }
@@ -920,16 +889,147 @@ int mips32_pracc_read_regs(struct mips_ejtag *ejtag_info, uint32_t *regs)
 
                MIPS32_LW(2,0,15),                                                              /* lw $2,($15) */
                MIPS32_LW(1,0,15),                                                              /* lw $1,($15) */
+               MIPS32_B(NEG16(58)),                                                    /* b start */
                MIPS32_MFC0(15,31,0),                                                   /* move COP0 DeSave to $15 */
-               MIPS32_NOP,
-               MIPS32_B(NEG16(60)),                                                    /* b start */
-               MIPS32_NOP,
        };
 
        int retval;
 
        retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, \
-               0, NULL, 38, regs, 1);
+               0, NULL, MIPS32NUMCOREREGS, regs, 1);
+
+       return retval;
+}
+
+/* fastdata upload/download requires an initialized working area
+ * to load the download code; it should not be called otherwise
+ * fetch order from the fastdata area
+ * 1. start addr
+ * 2. end addr
+ * 3. data ...
+ */
+int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_area *source,
+                                                               int write, uint32_t addr, int count, uint32_t *buf)
+{
+       uint32_t handler_code[] = {
+               /* caution when editing, table is modified below */
+               /* r15 points to the start of this code */
+               MIPS32_SW(8,MIPS32_FASTDATA_HANDLER_SIZE - 4,15),
+               MIPS32_SW(9,MIPS32_FASTDATA_HANDLER_SIZE - 8,15),
+               MIPS32_SW(10,MIPS32_FASTDATA_HANDLER_SIZE - 12,15),
+               MIPS32_SW(11,MIPS32_FASTDATA_HANDLER_SIZE - 16,15),
+               /* start of fastdata area in t0 */
+               MIPS32_LUI(8,UPPER16(MIPS32_PRACC_FASTDATA_AREA)),
+               MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_FASTDATA_AREA)),
+               MIPS32_LW(9,0,8),                                                               /* start addr in t1 */
+               MIPS32_LW(10,0,8),                                                              /* end addr to t2 */
+                                                                                                               /* loop: */
+               /* 8 */ MIPS32_LW(11,0,0),                                              /* lw t3,[t8 | r9] */
+               /* 9 */ MIPS32_SW(11,0,0),                                              /* sw t3,[r9 | r8] */
+               MIPS32_BNE(10,9,NEG16(3)),                                              /* bne $t2,t1,loop */
+               MIPS32_ADDI(9,9,4),                                                             /* addi t1,t1,4 */
+
+               MIPS32_LW(8,MIPS32_FASTDATA_HANDLER_SIZE - 4,15),
+               MIPS32_LW(9,MIPS32_FASTDATA_HANDLER_SIZE - 8,15),
+               MIPS32_LW(10,MIPS32_FASTDATA_HANDLER_SIZE - 12,15),
+               MIPS32_LW(11,MIPS32_FASTDATA_HANDLER_SIZE - 16,15),
+
+               MIPS32_LUI(15,UPPER16(MIPS32_PRACC_TEXT)),
+               MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_TEXT)),
+               MIPS32_JR(15),                                                                  /* jr start */
+               MIPS32_MFC0(15,31,0),                                                   /* move COP0 DeSave to $15 */
+       };
+
+       uint32_t jmp_code[] = {
+               MIPS32_MTC0(15,31,0),                   /* move $15 to COP0 DeSave */
+               /* 1 */ MIPS32_LUI(15,0),               /* addr of working area added below */
+               /* 2 */ MIPS32_ORI(15,15,0),    /* addr of working area added below */
+               MIPS32_JR(15),                                  /* jump to ram program */
+               MIPS32_NOP,
+       };
+
+       int retval, i;
+       uint32_t val, ejtag_ctrl, address;
+
+       if (source->size < MIPS32_FASTDATA_HANDLER_SIZE)
+               return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
+
+       if (write)
+       {
+               handler_code[8] = MIPS32_LW(11,0,8);    /* load data from probe at fastdata area */
+               handler_code[9] = MIPS32_SW(11,0,9);    /* store data to RAM @ r9 */
+       }
+       else
+       {
+               handler_code[8] = MIPS32_LW(11,0,9);    /* load data from RAM @ r9 */
+               handler_code[9] = MIPS32_SW(11,0,8);    /* store data to probe at fastdata area */
+       }
+
+       /* write program into RAM */
+       mips32_pracc_write_mem32(ejtag_info, source->address, ARRAY_SIZE(handler_code), handler_code);
+
+       LOG_DEBUG("%s using 0x%.8x for write handler\n", __func__, source->address);
+
+       jmp_code[1] |= UPPER16(source->address);
+       jmp_code[2] |= LOWER16(source->address);
+
+       for (i = 0; i < (int) ARRAY_SIZE(jmp_code); i++)
+       {
+               if ((retval = wait_for_pracc_rw(ejtag_info, &ejtag_ctrl)) != ERROR_OK)
+                       return retval;
+
+               mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);
+               mips_ejtag_drscan_32(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, NULL);
+               mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
+       }
+
+       if ((retval = wait_for_pracc_rw(ejtag_info, &ejtag_ctrl)) != ERROR_OK)
+               return retval;
+
+       /* next fetch to dmseg should be in FASTDATA_AREA, check */
+       address = 0;
+       mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);
+       mips_ejtag_drscan_32(ejtag_info, &address);
+
+       if (address != MIPS32_PRACC_FASTDATA_AREA)
+               return ERROR_FAIL;
+
+       /* Send the load start address */
+       val = addr;
+       mips_ejtag_set_instr(ejtag_info, EJTAG_INST_FASTDATA, NULL);
+       mips_ejtag_fastdata_scan(ejtag_info, 1, &val);
+
+       /* Send the load end address */
+       val = addr + (count - 1) * 4;
+       mips_ejtag_set_instr(ejtag_info, EJTAG_INST_FASTDATA, NULL);
+       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, buf++)) != ERROR_OK)
+                       return retval;
+       }
+
+       if ((retval = jtag_execute_queue()) != ERROR_OK)
+       {
+               LOG_ERROR("fastdata load failed");
+               return retval;
+       }
+
+       if ((retval = wait_for_pracc_rw(ejtag_info, &ejtag_ctrl)) != ERROR_OK)
+               return retval;
+
+       address = 0;
+       mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);
+       mips_ejtag_drscan_32(ejtag_info, &address);
+
+       if (address != MIPS32_PRACC_TEXT)
+               LOG_ERROR("mini program did not return to start\n");
 
        return retval;
 }