arm11.c

/***************************************************************************
 *   Copyright (C) 2008 digenius technology GmbH.                          *
 *   
 *   Copyright (C) 2008 Oyvind Harboe oyvind.harboe@zylin.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     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   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.             *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "arm11.h"
#include "jtag.h"
#include "log.h"

#include <stdlib.h>
#include <string.h>

#if 0
#define _DEBUG_INSTRUCTION_EXECUTION_
#endif


#if 0
#define FNC_INFO    LOG_DEBUG("-")
#else
#define FNC_INFO
#endif

#if 1
#define FNC_INFO_NOTIMPLEMENTED    do { LOG_DEBUG("NOT IMPLEMENTED"); /*exit(-1);*/ } while (0)
#else
#define FNC_INFO_NOTIMPLEMENTED
#endif

static void arm11_on_enter_debug_state(arm11_common_t * arm11);


bool	arm11_config_memwrite_burst		= true;
bool	arm11_config_memwrite_error_fatal	= true;
u32	arm11_vcr				= 0;


#define ARM11_HANDLER(x)	\
    .x				= arm11_##x

target_type_t arm11_target =
{
    .name			= "arm11",

    ARM11_HANDLER(poll),
    ARM11_HANDLER(arch_state),

    ARM11_HANDLER(target_request_data),

    ARM11_HANDLER(halt),
    ARM11_HANDLER(resume),
    ARM11_HANDLER(step),

    ARM11_HANDLER(assert_reset),
    ARM11_HANDLER(deassert_reset),
    ARM11_HANDLER(soft_reset_halt),
	
    ARM11_HANDLER(get_gdb_reg_list),
	
    ARM11_HANDLER(read_memory),
    ARM11_HANDLER(write_memory),
	
    ARM11_HANDLER(bulk_write_memory),
	
    ARM11_HANDLER(checksum_memory),

    ARM11_HANDLER(add_breakpoint),
    ARM11_HANDLER(remove_breakpoint),
    ARM11_HANDLER(add_watchpoint),
    ARM11_HANDLER(remove_watchpoint),

    ARM11_HANDLER(run_algorithm),
	
    ARM11_HANDLER(register_commands),
    ARM11_HANDLER(target_create),
    ARM11_HANDLER(init_target),
    ARM11_HANDLER(examine),
    ARM11_HANDLER(quit),
};

int arm11_regs_arch_type = -1;


enum arm11_regtype
{
    ARM11_REGISTER_CORE,
    ARM11_REGISTER_CPSR,

    ARM11_REGISTER_FX,
    ARM11_REGISTER_FPS,

    ARM11_REGISTER_FIQ,
    ARM11_REGISTER_SVC,
    ARM11_REGISTER_ABT,
    ARM11_REGISTER_IRQ,
    ARM11_REGISTER_UND,
    ARM11_REGISTER_MON,

    ARM11_REGISTER_SPSR_FIQ,
    ARM11_REGISTER_SPSR_SVC,
    ARM11_REGISTER_SPSR_ABT,
    ARM11_REGISTER_SPSR_IRQ,
    ARM11_REGISTER_SPSR_UND,
    ARM11_REGISTER_SPSR_MON,

    /* debug regs */
    ARM11_REGISTER_DSCR,
    ARM11_REGISTER_WDTR,
    ARM11_REGISTER_RDTR,
};


typedef struct arm11_reg_defs_s
{
    char *			name;
    u32				num;
    int				gdb_num;
    enum arm11_regtype		type;
} arm11_reg_defs_t;

/* update arm11_regcache_ids when changing this */
static const arm11_reg_defs_t arm11_reg_defs[] =
{
    {"r0",	0,	0,	ARM11_REGISTER_CORE},
    {"r1",	1,	1,	ARM11_REGISTER_CORE},
    {"r2",	2,	2,	ARM11_REGISTER_CORE},
    {"r3",	3,	3,	ARM11_REGISTER_CORE},
    {"r4",	4,	4,	ARM11_REGISTER_CORE},
    {"r5",	5,	5,	ARM11_REGISTER_CORE},
    {"r6",	6,	6,	ARM11_REGISTER_CORE},
    {"r7",	7,	7,	ARM11_REGISTER_CORE},
    {"r8",	8,	8,	ARM11_REGISTER_CORE},
    {"r9",	9,	9,	ARM11_REGISTER_CORE},
    {"r10",	10,	10,	ARM11_REGISTER_CORE},
    {"r11",	11,	11,	ARM11_REGISTER_CORE},
    {"r12",	12,	12,	ARM11_REGISTER_CORE},
    {"sp",	13,	13,	ARM11_REGISTER_CORE},
    {"lr",	14,	14,	ARM11_REGISTER_CORE},
    {"pc",	15,	15,	ARM11_REGISTER_CORE},

#if ARM11_REGCACHE_FREGS
    {"f0",	0,	16,	ARM11_REGISTER_FX},
    {"f1",	1,	17,	ARM11_REGISTER_FX},
    {"f2",	2,	18,	ARM11_REGISTER_FX},
    {"f3",	3,	19,	ARM11_REGISTER_FX},
    {"f4",	4,	20,	ARM11_REGISTER_FX},
    {"f5",	5,	21,	ARM11_REGISTER_FX},
    {"f6",	6,	22,	ARM11_REGISTER_FX},
    {"f7",	7,	23,	ARM11_REGISTER_FX},
    {"fps",	0,	24,	ARM11_REGISTER_FPS},
#endif

    {"cpsr",	0,	25,	ARM11_REGISTER_CPSR},

#if ARM11_REGCACHE_MODEREGS
    {"r8_fiq",	8,	-1,	ARM11_REGISTER_FIQ},
    {"r9_fiq",	9,	-1,	ARM11_REGISTER_FIQ},
    {"r10_fiq",	10,	-1,	ARM11_REGISTER_FIQ},
    {"r11_fiq",	11,	-1,	ARM11_REGISTER_FIQ},
    {"r12_fiq",	12,	-1,	ARM11_REGISTER_FIQ},
    {"r13_fiq",	13,	-1,	ARM11_REGISTER_FIQ},
    {"r14_fiq",	14,	-1,	ARM11_REGISTER_FIQ},
    {"spsr_fiq", 0,	-1,	ARM11_REGISTER_SPSR_FIQ},

    {"r13_svc",	13,	-1,	ARM11_REGISTER_SVC},
    {"r14_svc",	14,	-1,	ARM11_REGISTER_SVC},
    {"spsr_svc", 0,	-1,	ARM11_REGISTER_SPSR_SVC},

    {"r13_abt",	13,	-1,	ARM11_REGISTER_ABT},
    {"r14_abt",	14,	-1,	ARM11_REGISTER_ABT},
    {"spsr_abt", 0,	-1,	ARM11_REGISTER_SPSR_ABT},

    {"r13_irq",	13,	-1,	ARM11_REGISTER_IRQ},
    {"r14_irq",	14,	-1,	ARM11_REGISTER_IRQ},
    {"spsr_irq", 0,	-1,	ARM11_REGISTER_SPSR_IRQ},

    {"r13_und",	13,	-1,	ARM11_REGISTER_UND},
    {"r14_und",	14,	-1,	ARM11_REGISTER_UND},
    {"spsr_und", 0,	-1,	ARM11_REGISTER_SPSR_UND},

    /* ARM1176 only */
    {"r13_mon",	13,	-1,	ARM11_REGISTER_MON},
    {"r14_mon",	14,	-1,	ARM11_REGISTER_MON},
    {"spsr_mon", 0,	-1,	ARM11_REGISTER_SPSR_MON},
#endif

    /* Debug Registers */
    {"dscr",	0,	-1,	ARM11_REGISTER_DSCR},
    {"wdtr",	0,	-1,	ARM11_REGISTER_WDTR},
    {"rdtr",	0,	-1,	ARM11_REGISTER_RDTR},
};

enum arm11_regcache_ids
{
    ARM11_RC_R0,
    ARM11_RC_RX			= ARM11_RC_R0,

    ARM11_RC_R1,
    ARM11_RC_R2,
    ARM11_RC_R3,
    ARM11_RC_R4,
    ARM11_RC_R5,
    ARM11_RC_R6,
    ARM11_RC_R7,
    ARM11_RC_R8,
    ARM11_RC_R9,
    ARM11_RC_R10,
    ARM11_RC_R11,
    ARM11_RC_R12,
    ARM11_RC_R13,
    ARM11_RC_SP			= ARM11_RC_R13,
    ARM11_RC_R14,
    ARM11_RC_LR			= ARM11_RC_R14,
    ARM11_RC_R15,
    ARM11_RC_PC			= ARM11_RC_R15,

#if ARM11_REGCACHE_FREGS
    ARM11_RC_F0,
    ARM11_RC_FX			= ARM11_RC_F0,
    ARM11_RC_F1,
    ARM11_RC_F2,
    ARM11_RC_F3,
    ARM11_RC_F4,
    ARM11_RC_F5,
    ARM11_RC_F6,
    ARM11_RC_F7,
    ARM11_RC_FPS,
#endif

    ARM11_RC_CPSR,

#if ARM11_REGCACHE_MODEREGS
    ARM11_RC_R8_FIQ,
    ARM11_RC_R9_FIQ,
    ARM11_RC_R10_FIQ,
    ARM11_RC_R11_FIQ,
    ARM11_RC_R12_FIQ,
    ARM11_RC_R13_FIQ,
    ARM11_RC_R14_FIQ,
    ARM11_RC_SPSR_FIQ,

    ARM11_RC_R13_SVC,
    ARM11_RC_R14_SVC,
    ARM11_RC_SPSR_SVC,

    ARM11_RC_R13_ABT,
    ARM11_RC_R14_ABT,
    ARM11_RC_SPSR_ABT,

    ARM11_RC_R13_IRQ,
    ARM11_RC_R14_IRQ,
    ARM11_RC_SPSR_IRQ,

    ARM11_RC_R13_UND,
    ARM11_RC_R14_UND,
    ARM11_RC_SPSR_UND,

    ARM11_RC_R13_MON,
    ARM11_RC_R14_MON,
    ARM11_RC_SPSR_MON,
#endif

    ARM11_RC_DSCR,
    ARM11_RC_WDTR,
    ARM11_RC_RDTR,

    ARM11_RC_MAX,
};

#define ARM11_GDB_REGISTER_COUNT	26

u8 arm11_gdb_dummy_fp_value[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

reg_t arm11_gdb_dummy_fp_reg =
{
    "GDB dummy floating-point register", arm11_gdb_dummy_fp_value, 0, 1, 96, NULL, 0, NULL, 0
};

u8 arm11_gdb_dummy_fps_value[] = {0, 0, 0, 0};

reg_t arm11_gdb_dummy_fps_reg =
{
    "GDB dummy floating-point status register", arm11_gdb_dummy_fps_value, 0, 1, 32, NULL, 0, NULL, 0
};



/** Check and if necessary take control of the system
 *
 * \param arm11		Target state variable.
 * \param dscr		If the current DSCR content is
 *		        available a pointer to a word holding the
 *		        DSCR can be passed. Otherwise use NULL.
 */
void arm11_check_init(arm11_common_t * arm11, u32 * dscr)
{
    FNC_INFO;

    u32			dscr_local_tmp_copy;

    if (!dscr)
    {
	dscr = &dscr_local_tmp_copy;
	*dscr = arm11_read_DSCR(arm11);
    }

    if (!(*dscr & ARM11_DSCR_MODE_SELECT))
    {
	LOG_DEBUG("Bringing target into debug mode");

	*dscr |= ARM11_DSCR_MODE_SELECT;		/* Halt debug-mode */
	arm11_write_DSCR(arm11, *dscr);

	/* add further reset initialization here */

	arm11->simulate_reset_on_next_halt = true;

	if (*dscr & ARM11_DSCR_CORE_HALTED)
	{
	    /** \todo TODO: this needs further scrutiny because
	      * arm11_on_enter_debug_state() never gets properly called
	      */

	    arm11->target->state	= TARGET_HALTED;
	    arm11->target->debug_reason	= arm11_get_DSCR_debug_reason(*dscr);
	}
	else
	{
	    arm11->target->state	= TARGET_RUNNING;
	    arm11->target->debug_reason	= DBG_REASON_NOTHALTED;
	}

	arm11_sc7_clear_vbw(arm11);
    }
}



#define R(x) \
    (arm11->reg_values[ARM11_RC_##x])

/** Save processor state.
  *
  * This is called when the HALT instruction has succeeded
  * or on other occasions that stop the processor.
  *
  */
static void arm11_on_enter_debug_state(arm11_common_t * arm11)
{
    FNC_INFO;

    {size_t i;
    for(i = 0; i < asizeof(arm11->reg_values); i++)
    {
	arm11->reg_list[i].valid	= 1;
	arm11->reg_list[i].dirty	= 0;
    }}

    /* Save DSCR */

    R(DSCR) = arm11_read_DSCR(arm11);

    /* Save wDTR */

    if (R(DSCR) & ARM11_DSCR_WDTR_FULL)
    {
	arm11_add_debug_SCAN_N(arm11, 0x05, -1);

	arm11_add_IR(arm11, ARM11_INTEST, -1);

	scan_field_t	chain5_fields[3];

	arm11_setup_field(arm11, 32, NULL, &R(WDTR),	chain5_fields + 0);
	arm11_setup_field(arm11,  1, NULL, NULL,	chain5_fields + 1);
	arm11_setup_field(arm11,  1, NULL, NULL,	chain5_fields + 2);

	arm11_add_dr_scan_vc(asizeof(chain5_fields), chain5_fields, TAP_PD);
    }
    else
    {
	arm11->reg_list[ARM11_RC_WDTR].valid	= 0;
    }


    /* DSCR: set ARM11_DSCR_EXECUTE_ARM_INSTRUCTION_ENABLE */
    /* ARM1176 spec says this is needed only for wDTR/rDTR's "ITR mode", but not to issue ITRs
       ARM1136 seems to require this to issue ITR's as well */

    u32 new_dscr = R(DSCR) | ARM11_DSCR_EXECUTE_ARM_INSTRUCTION_ENABLE;

    /* this executes JTAG queue: */ 

    arm11_write_DSCR(arm11, new_dscr);


    /* From the spec:
	Before executing any instruction in debug state you have to drain the write buffer.
        This ensures that no imprecise Data Aborts can return at a later point:*/

    /** \todo TODO: Test drain write buffer. */

#if 0
    while (1)
    {
	/* MRC p14,0,R0,c5,c10,0 */
//	arm11_run_instr_no_data1(arm11, /*0xee150e1a*/0xe320f000);

	/* mcr     15, 0, r0, cr7, cr10, {4} */
	arm11_run_instr_no_data1(arm11, 0xee070f9a);
	        
	u32 dscr = arm11_read_DSCR(arm11);

	LOG_DEBUG("DRAIN, DSCR %08x", dscr);

	if (dscr & ARM11_DSCR_STICKY_IMPRECISE_DATA_ABORT)
	{
	    arm11_run_instr_no_data1(arm11, 0xe320f000);

	    dscr = arm11_read_DSCR(arm11);

	    LOG_DEBUG("DRAIN, DSCR %08x (DONE)", dscr);

	    break;
	}
    }
#endif


    arm11_run_instr_data_prepare(arm11);

    /* save r0 - r14 */


    /** \todo TODO: handle other mode registers */

    {size_t i;
    for (i = 0; i < 15; i++)
    {
	/* MCR p14,0,R?,c0,c5,0 */
	arm11_run_instr_data_from_core(arm11, 0xEE000E15 | (i << 12), &R(RX + i), 1);
    }}


    /* save rDTR */

    /* check rDTRfull in DSCR */

    if (R(DSCR) & ARM11_DSCR_RDTR_FULL)
    {
	/* MRC p14,0,R0,c0,c5,0 (move rDTR -> r0 (-> wDTR -> local var)) */
	arm11_run_instr_data_from_core_via_r0(arm11, 0xEE100E15, &R(RDTR));
    }
    else
    {
	arm11->reg_list[ARM11_RC_RDTR].valid	= 0;
    }

    /* save CPSR */

    /* MRS r0,CPSR (move CPSR -> r0 (-> wDTR -> local var)) */
    arm11_run_instr_data_from_core_via_r0(arm11, 0xE10F0000, &R(CPSR));

    /* save PC */

    /* MOV R0,PC (move PC -> r0 (-> wDTR -> local var)) */
    arm11_run_instr_data_from_core_via_r0(arm11, 0xE1A0000F, &R(PC));

    /* adjust PC depending on ARM state */

    if (R(CPSR) & ARM11_CPSR_J)	/* Java state */
    {
	arm11->reg_values[ARM11_RC_PC] -= 0;
    }
    else if (R(CPSR) & ARM11_CPSR_T)	/* Thumb state */
    {
	arm11->reg_values[ARM11_RC_PC] -= 4;
    }
    else					/* ARM state */
    {
	arm11->reg_values[ARM11_RC_PC] -= 8;
    }

    if (arm11->simulate_reset_on_next_halt)
    {
	arm11->simulate_reset_on_next_halt = false;

	LOG_DEBUG("Reset c1 Control Register");

	/* Write 0 (reset value) to Control register 0 to disable MMU/Cache etc. */

	/* MCR p15,0,R0,c1,c0,0 */
	arm11_run_instr_data_to_core_via_r0(arm11, 0xee010f10, 0);

    }

    arm11_run_instr_data_finish(arm11);

    arm11_dump_reg_changes(arm11);
}

void arm11_dump_reg_changes(arm11_common_t * arm11)
{
    {size_t i;
    for(i = 0; i < ARM11_REGCACHE_COUNT; i++)
    {
	if (!arm11->reg_list[i].valid)
	{
	    if (arm11->reg_history[i].valid)
		LOG_INFO("%8s INVALID    (%08x)", arm11_reg_defs[i].name, arm11->reg_history[i].value);
	}
	else
	{
	    if (arm11->reg_history[i].valid)
	    {
		if (arm11->reg_history[i].value != arm11->reg_values[i])
		    LOG_INFO("%8s %08x (%08x)", arm11_reg_defs[i].name, arm11->reg_values[i], arm11->reg_history[i].value);
	    }
	    else
	    {
		LOG_INFO("%8s %08x (INVALID)", arm11_reg_defs[i].name, arm11->reg_values[i]);
	    }
	}
    }}
}


/** Restore processor state
  *
  * This is called in preparation for the RESTART function.
  *
  */
void arm11_leave_debug_state(arm11_common_t * arm11)
{
    FNC_INFO;

    arm11_run_instr_data_prepare(arm11);

    /** \todo TODO: handle other mode registers */

    /* restore R1 - R14 */
    {size_t i;
    for (i = 1; i < 15; i++)
    {
	if (!arm11->reg_list[ARM11_RC_RX + i].dirty)
	    continue;

	/* MRC p14,0,r?,c0,c5,0 */
	arm11_run_instr_data_to_core1(arm11, 0xee100e15 | (i << 12), R(RX + i));

//	LOG_DEBUG("RESTORE R" ZU " %08x", i, R(RX + i));
    }}

    arm11_run_instr_data_finish(arm11);


    /* spec says clear wDTR and rDTR; we assume they are clear as
       otherwise our programming would be sloppy */

    {
	u32 DSCR = arm11_read_DSCR(arm11);

	if (DSCR & (ARM11_DSCR_RDTR_FULL | ARM11_DSCR_WDTR_FULL))
	{
	    LOG_ERROR("wDTR/rDTR inconsistent (DSCR %08x)", DSCR);
	}
    }

    arm11_run_instr_data_prepare(arm11);

    /* restore original wDTR */

    if ((R(DSCR) & ARM11_DSCR_WDTR_FULL) || arm11->reg_list[ARM11_RC_WDTR].dirty)
    {
	/* MCR p14,0,R0,c0,c5,0 */
	arm11_run_instr_data_to_core_via_r0(arm11, 0xee000e15, R(WDTR));
    }

    /* restore CPSR */

    /* MSR CPSR,R0*/
    arm11_run_instr_data_to_core_via_r0(arm11, 0xe129f000, R(CPSR));


    /* restore PC */

    /* MOV PC,R0 */
    arm11_run_instr_data_to_core_via_r0(arm11, 0xe1a0f000, R(PC));


    /* restore R0 */

    /* MRC p14,0,r0,c0,c5,0 */
    arm11_run_instr_data_to_core1(arm11, 0xee100e15, R(R0));

    arm11_run_instr_data_finish(arm11);


    /* restore DSCR */

    arm11_write_DSCR(arm11, R(DSCR));


    /* restore rDTR */
    
    if (R(DSCR) & ARM11_DSCR_RDTR_FULL || arm11->reg_list[ARM11_RC_RDTR].dirty)
    {
	arm11_add_debug_SCAN_N(arm11, 0x05, -1);

	arm11_add_IR(arm11, ARM11_EXTEST, -1);

	scan_field_t	chain5_fields[3];

	u8			Ready	    = 0;	/* ignored */
	u8			Valid	    = 0;	/* ignored */

	arm11_setup_field(arm11, 32, &R(RDTR),	NULL, chain5_fields + 0);
	arm11_setup_field(arm11,  1, &Ready,	NULL, chain5_fields + 1);
	arm11_setup_field(arm11,  1, &Valid,	NULL, chain5_fields + 2);

	arm11_add_dr_scan_vc(asizeof(chain5_fields), chain5_fields, TAP_PD);
    }

    arm11_record_register_history(arm11);
}

void arm11_record_register_history(arm11_common_t * arm11)
{
    {size_t i;
    for(i = 0; i < ARM11_REGCACHE_COUNT; i++)
    {
	arm11->reg_history[i].value	= arm11->reg_values[i];
	arm11->reg_history[i].valid	= arm11->reg_list[i].valid;

	arm11->reg_list[i].valid	= 0;
	arm11->reg_list[i].dirty	= 0;
    }}
}


/* poll current target status */
int arm11_poll(struct target_s *target)
{
    FNC_INFO;

    arm11_common_t * arm11 = target->arch_info;

    if (arm11->trst_active)
	return ERROR_OK;

    u32	dscr = arm11_read_DSCR(arm11);

    LOG_DEBUG("DSCR %08x", dscr);

    arm11_check_init(arm11, &dscr);

    if (dscr & ARM11_DSCR_CORE_HALTED)
    {
	if (target->state != TARGET_HALTED)
	{
	    enum target_state old_state = target->state;

	    LOG_DEBUG("enter TARGET_HALTED");
	    target->state		= TARGET_HALTED;
	    target->debug_reason	= arm11_get_DSCR_debug_reason(dscr);
	    arm11_on_enter_debug_state(arm11);

	    target_call_event_callbacks(target,
		old_state == TARGET_DEBUG_RUNNING ? TARGET_EVENT_DEBUG_HALTED : TARGET_EVENT_HALTED);
	}
    }
    else
    {
	if (target->state != TARGET_RUNNING && target->state != TARGET_DEBUG_RUNNING)
	{
	    LOG_DEBUG("enter TARGET_RUNNING");
	    target->state		= TARGET_RUNNING;
	    target->debug_reason	= DBG_REASON_NOTHALTED;
	}
    }

    return ERROR_OK;
}
/* architecture specific status reply */
int arm11_arch_state(struct target_s *target)
{
    FNC_INFO_NOTIMPLEMENTED;

    return ERROR_OK;
}


/* target request support */
int arm11_target_request_data(struct target_s *target, u32 size, u8 *buffer)
{
    FNC_INFO_NOTIMPLEMENTED;

    return ERROR_OK;
}



/* target execution control */
int arm11_halt(struct target_s *target)
{
    FNC_INFO;

    arm11_common_t * arm11 = target->arch_info;

    LOG_DEBUG("target->state: %s", 
	      Jim_Nvp_value2name_simple( nvp_target_state, target->state )->name );

    if (target->state == TARGET_UNKNOWN)
    {
	arm11->simulate_reset_on_next_halt = true;
    }

    if (target->state == TARGET_HALTED)
    {
		LOG_DEBUG("target was already halted");
		return ERROR_OK;
    }

    if (arm11->trst_active)
    {
	arm11->halt_requested = true;
	return ERROR_OK;
    }

    arm11_add_IR(arm11, ARM11_HALT, TAP_RTI);

    jtag_execute_queue();

    u32 dscr;

    while (1)
    {
	dscr = arm11_read_DSCR(arm11);

	if (dscr & ARM11_DSCR_CORE_HALTED)
	    break;
    }

    arm11_on_enter_debug_state(arm11);

    enum target_state old_state	= target->state;

    target->state		= TARGET_HALTED;
    target->debug_reason	= arm11_get_DSCR_debug_reason(dscr);

    target_call_event_callbacks(target,
	old_state == TARGET_DEBUG_RUNNING ? TARGET_EVENT_DEBUG_HALTED : TARGET_EVENT_HALTED);

    return ERROR_OK;
}


int arm11_resume(struct target_s *target, int current, u32 address, int handle_breakpoints, int debug_execution)
{
    FNC_INFO;

//    LOG_DEBUG("current %d  address %08x  handle_breakpoints %d  debug_execution %d",
//	current, address, handle_breakpoints, debug_execution);

    arm11_common_t * arm11 = target->arch_info;

    LOG_DEBUG("target->state: %s", 
	      Jim_Nvp_value2name_simple( nvp_target_state, target->state )->name );


    if (target->state != TARGET_HALTED)
	{
		LOG_ERROR("Target not halted");
		return ERROR_TARGET_NOT_HALTED;
	}

    if (!current)
	R(PC) = address;

    LOG_INFO("RESUME PC %08x%s", R(PC), !current ? "!" : "");

    /* clear breakpoints/watchpoints and VCR*/
    arm11_sc7_clear_vbw(arm11);

    /* Set up breakpoints */
    if (!debug_execution)
    {
	/* check if one matches PC and step over it if necessary */

	breakpoint_t *	bp;

	for (bp = target->breakpoints; bp; bp = bp->next)
	{
	    if (bp->address == R(PC))
	    {
		LOG_DEBUG("must step over %08x", bp->address);
		arm11_step(target, 1, 0, 0);
		break;
	    }
	}

	/* set all breakpoints */

	size_t		brp_num = 0;
	
	for (bp = target->breakpoints; bp; bp = bp->next)
	{
	    arm11_sc7_action_t	brp[2];

	    brp[0].write	= 1;
	    brp[0].address	= ARM11_SC7_BVR0 + brp_num;
	    brp[0].value	= bp->address;
	    brp[1].write	= 1;
	    brp[1].address	= ARM11_SC7_BCR0 + brp_num;
	    brp[1].value	= 0x1 | (3 << 1) | (0x0F << 5) | (0 << 14) | (0 << 16) | (0 << 20) | (0 << 21);
    
	    arm11_sc7_run(arm11, brp, asizeof(brp));

	    LOG_DEBUG("Add BP " ZU " at %08x", brp_num, bp->address);

	    brp_num++;
	}

	arm11_sc7_set_vcr(arm11, arm11_vcr);
    }


    arm11_leave_debug_state(arm11);

    arm11_add_IR(arm11, ARM11_RESTART, TAP_RTI);

    jtag_execute_queue();

    while (1)
    {
	u32 dscr = arm11_read_DSCR(arm11);

	LOG_DEBUG("DSCR %08x", dscr);

	if (dscr & ARM11_DSCR_CORE_RESTARTED)
	    break;
    }

    if (!debug_execution)
    {
	target->state		= TARGET_RUNNING;
	target->debug_reason	= DBG_REASON_NOTHALTED;
	target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
    }
    else
    {
	target->state		= TARGET_DEBUG_RUNNING;
	target->debug_reason	= DBG_REASON_NOTHALTED;
	target_call_event_callbacks(target, TARGET_EVENT_DEBUG_RESUMED);
    }

    return ERROR_OK;
}

int arm11_step(struct target_s *target, int current, u32 address, int handle_breakpoints)
{
    FNC_INFO;

    LOG_DEBUG("target->state: %s", 
	      Jim_Nvp_value2name_simple( nvp_target_state, target->state )->name );

    if (target->state != TARGET_HALTED)
    {
	LOG_WARNING("target was not halted");
	return ERROR_TARGET_NOT_HALTED;
    }

    arm11_common_t * arm11 = target->arch_info;

    if (!current)
	R(PC) = address;

    LOG_INFO("STEP PC %08x%s", R(PC), !current ? "!" : "");

    /** \todo TODO: Thumb not supported here */

    u32	next_instruction;

    arm11_read_memory_word(arm11, R(PC), &next_instruction);

    /* skip over BKPT */
    if ((next_instruction & 0xFFF00070) == 0xe1200070)
    {
	R(PC) += 4;
	arm11->reg_list[ARM11_RC_PC].valid = 1;
	arm11->reg_list[ARM11_RC_PC].dirty = 0;
	LOG_INFO("Skipping BKPT");
    }
    /* skip over Wait for interrupt / Standby */
    /* mcr	15, 0, r?, cr7, cr0, {4} */
    else if ((next_instruction & 0xFFFF0FFF) == 0xee070f90)
    {
	R(PC) += 4;
	arm11->reg_list[ARM11_RC_PC].valid = 1;
	arm11->reg_list[ARM11_RC_PC].dirty = 0;
	LOG_INFO("Skipping WFI");
    }
    /* ignore B to self */
    else if ((next_instruction & 0xFEFFFFFF) == 0xeafffffe)
    {
	LOG_INFO("Not stepping jump to self");
    }
    else
    {
	/** \todo TODO: check if break-/watchpoints make any sense at all in combination
	  * with this. */

	/** \todo TODO: check if disabling IRQs might be a good idea here. Alternatively
	  * the VCR might be something worth looking into. */


	/* Set up breakpoint for stepping */

	arm11_sc7_action_t	brp[2];

	brp[0].write	= 1;
	brp[0].address	= ARM11_SC7_BVR0;
	brp[0].value	= R(PC);
	brp[1].write	= 1;
	brp[1].address	= ARM11_SC7_BCR0;
	brp[1].value	= 0x1 | (3 << 1) | (0x0F << 5) | (0 << 14) | (0 << 16) | (0 << 20) | (2 << 21);

	arm11_sc7_run(arm11, brp, asizeof(brp));

	/* resume */

	arm11_leave_debug_state(arm11);

	arm11_add_IR(arm11, ARM11_RESTART, TAP_RTI);

	jtag_execute_queue();

	/** \todo TODO: add a timeout */

	/* wait for halt */

	while (1)
	{
	    u32 dscr = arm11_read_DSCR(arm11);

	    LOG_DEBUG("DSCR %08x", dscr);

	    if ((dscr & (ARM11_DSCR_CORE_RESTARTED | ARM11_DSCR_CORE_HALTED)) ==
		(ARM11_DSCR_CORE_RESTARTED | ARM11_DSCR_CORE_HALTED))
		break;
	}

	/* clear breakpoint */
	arm11_sc7_clear_vbw(arm11);

	/* save state */
	arm11_on_enter_debug_state(arm11);
    }

//    target->state		= TARGET_HALTED;
    target->debug_reason	= DBG_REASON_SINGLESTEP;

    target_call_event_callbacks(target, TARGET_EVENT_HALTED);

    return ERROR_OK;
}


/* target reset control */
int arm11_assert_reset(struct target_s *target)
{
    FNC_INFO;

#if 0
    /* assert reset lines */
    /* resets only the DBGTAP, not the ARM */

    jtag_add_reset(1, 0);
    jtag_add_sleep(5000);

    arm11_common_t * arm11 = target->arch_info;