[openocd.git] / src / target / cortex_a8.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2006 by Magnus Lundin                                   *
 *   lundin@mlu.mine.nu                                                    *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   Copyright (C) 2009 by Dirk Behme                                      *
 *   dirk.behme@gmail.com - copy from cortex_m3                            *
 *                                                                         *
 *   Copyright (C) 2010 Øyvind 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.             *
 *                                                                         *
 *   Cortex-A8(tm) TRM, ARM DDI 0344H                                      *
 *                                                                         *
 ***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "breakpoints.h"
#include "cortex_a8.h"
#include "register.h"
#include "target_request.h"
#include "target_type.h"
#include "arm_opcodes.h"
#include <helper/time_support.h>

static int cortex_a8_poll(struct target *target);
static int cortex_a8_debug_entry(struct target *target);
static int cortex_a8_restore_context(struct target *target, bool bpwp);
static int cortex_a8_set_breakpoint(struct target *target,
                struct breakpoint *breakpoint, uint8_t matchmode);
static int cortex_a8_unset_breakpoint(struct target *target,
                struct breakpoint *breakpoint);
static int cortex_a8_dap_read_coreregister_u32(struct target *target,
                uint32_t *value, int regnum);
static int cortex_a8_dap_write_coreregister_u32(struct target *target,
                uint32_t value, int regnum);
static int cortex_a8_mmu(struct target *target, int *enabled);
static int cortex_a8_virt2phys(struct target *target,
                uint32_t virt, uint32_t *phys);
static void cortex_a8_disable_mmu_caches(struct target *target, int mmu,
                int d_u_cache, int i_cache);
static void cortex_a8_enable_mmu_caches(struct target *target, int mmu,
                int d_u_cache, int i_cache);
static uint32_t cortex_a8_get_ttb(struct target *target);


/*
 * FIXME do topology discovery using the ROM; don't
 * assume this is an OMAP3.   Also, allow for multiple ARMv7-A
 * cores, with different AP numbering ... don't use a #define
 * for these numbers, use per-core armv7a state.
 */
#define swjdp_memoryap 0
#define swjdp_debugap 1
#define OMAP3530_DEBUG_BASE 0x54011000

/*
 * Cortex-A8 Basic debug access, very low level assumes state is saved
 */
static int cortex_a8_init_debug_access(struct target *target)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        int retval;
        uint32_t dummy;

        LOG_DEBUG(" ");

        /* Unlocking the debug registers for modification */
        /* The debugport might be uninitialised so try twice */
        retval = mem_ap_write_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_LOCKACCESS, 0xC5ACCE55);
        if (retval != ERROR_OK)
        {
                /* try again */
                retval = mem_ap_write_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_LOCKACCESS, 0xC5ACCE55);
                if (retval == ERROR_OK)
                {
                        LOG_USER("Locking debug access failed on first, but succeeded on second try.");
                }
        }
        if (retval != ERROR_OK)
                return retval;
        /* Clear Sticky Power Down status Bit in PRSR to enable access to
           the registers in the Core Power Domain */
        retval = mem_ap_read_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_PRSR, &dummy);
        if (retval != ERROR_OK)
                return retval;

        /* Enabling of instruction execution in debug mode is done in debug_entry code */

        /* Resync breakpoint registers */

        /* Since this is likely called from init or reset, update target state information*/
        retval = cortex_a8_poll(target);

        return retval;
}

/* To reduce needless round-trips, pass in a pointer to the current
 * DSCR value.  Initialize it to zero if you just need to know the
 * value on return from this function; or DSCR_INSTR_COMP if you
 * happen to know that no instruction is pending.
 */
static int cortex_a8_exec_opcode(struct target *target,
                uint32_t opcode, uint32_t *dscr_p)
{
        uint32_t dscr;
        int retval;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        dscr = dscr_p ? *dscr_p : 0;

        LOG_DEBUG("exec opcode 0x%08" PRIx32, opcode);

        /* Wait for InstrCompl bit to be set */
        while ((dscr & DSCR_INSTR_COMP) == 0)
        {
                retval = mem_ap_read_atomic_u32(swjdp,
                                armv7a->debug_base + CPUDBG_DSCR, &dscr);
                if (retval != ERROR_OK)
                {
                        LOG_ERROR("Could not read DSCR register, opcode = 0x%08" PRIx32, opcode);
                        return retval;
                }
        }

        mem_ap_write_u32(swjdp, armv7a->debug_base + CPUDBG_ITR, opcode);

        do
        {
                retval = mem_ap_read_atomic_u32(swjdp,
                                armv7a->debug_base + CPUDBG_DSCR, &dscr);
                if (retval != ERROR_OK)
                {
                        LOG_ERROR("Could not read DSCR register");
                        return retval;
                }
        }
        while ((dscr & DSCR_INSTR_COMP) == 0); /* Wait for InstrCompl bit to be set */

        if (dscr_p)
                *dscr_p = dscr;

        return retval;
}

/**************************************************************************
Read core register with very few exec_opcode, fast but needs work_area.
This can cause problems with MMU active.
**************************************************************************/
static int cortex_a8_read_regs_through_mem(struct target *target, uint32_t address,
                uint32_t * regfile)
{
        int retval = ERROR_OK;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        cortex_a8_dap_read_coreregister_u32(target, regfile, 0);
        cortex_a8_dap_write_coreregister_u32(target, address, 0);
        cortex_a8_exec_opcode(target, ARMV4_5_STMIA(0, 0xFFFE, 0, 0), NULL);
        dap_ap_select(swjdp, swjdp_memoryap);
        mem_ap_read_buf_u32(swjdp, (uint8_t *)(&regfile[1]), 4*15, address);
        dap_ap_select(swjdp, swjdp_debugap);

        return retval;
}

static int cortex_a8_dap_read_coreregister_u32(struct target *target,
                uint32_t *value, int regnum)
{
        int retval = ERROR_OK;
        uint8_t reg = regnum&0xFF;
        uint32_t dscr = 0;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        if (reg > 17)
                return retval;

        if (reg < 15)
        {
                /* Rn to DCCTX, "MCR p14, 0, Rn, c0, c5, 0"  0xEE00nE15 */
                cortex_a8_exec_opcode(target,
                                ARMV4_5_MCR(14, 0, reg, 0, 5, 0),
                                &dscr);
        }
        else if (reg == 15)
        {
                /* "MOV r0, r15"; then move r0 to DCCTX */
                cortex_a8_exec_opcode(target, 0xE1A0000F, &dscr);
                cortex_a8_exec_opcode(target,
                                ARMV4_5_MCR(14, 0, 0, 0, 5, 0),
                                &dscr);
        }
        else
        {
                /* "MRS r0, CPSR" or "MRS r0, SPSR"
                 * then move r0 to DCCTX
                 */
                cortex_a8_exec_opcode(target, ARMV4_5_MRS(0, reg & 1), &dscr);
                cortex_a8_exec_opcode(target,
                                ARMV4_5_MCR(14, 0, 0, 0, 5, 0),
                                &dscr);
        }

        /* Wait for DTRRXfull then read DTRRTX */
        while ((dscr & DSCR_DTR_TX_FULL) == 0)
        {
                retval = mem_ap_read_atomic_u32(swjdp,
                                armv7a->debug_base + CPUDBG_DSCR, &dscr);
                if (retval != ERROR_OK)
                        return retval;
        }

        retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DTRTX, value);
        LOG_DEBUG("read DCC 0x%08" PRIx32, *value);

        return retval;
}

static int cortex_a8_dap_write_coreregister_u32(struct target *target,
                uint32_t value, int regnum)
{
        int retval = ERROR_OK;
        uint8_t Rd = regnum&0xFF;
        uint32_t dscr;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        LOG_DEBUG("register %i, value 0x%08" PRIx32, regnum, value);

        /* Check that DCCRX is not full */
        retval = mem_ap_read_atomic_u32(swjdp,
                                armv7a->debug_base + CPUDBG_DSCR, &dscr);
        if (retval != ERROR_OK)
                return retval;
        if (dscr & DSCR_DTR_RX_FULL)
        {
                LOG_ERROR("DSCR_DTR_RX_FULL, dscr 0x%08" PRIx32, dscr);
                /* Clear DCCRX with MCR(p14, 0, Rd, c0, c5, 0), opcode  0xEE000E15 */
                cortex_a8_exec_opcode(target, ARMV4_5_MRC(14, 0, 0, 0, 5, 0),
                                &dscr);
        }

        if (Rd > 17)
                return retval;

        /* Write DTRRX ... sets DSCR.DTRRXfull but exec_opcode() won't care */
        LOG_DEBUG("write DCC 0x%08" PRIx32, value);
        retval = mem_ap_write_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DTRRX, value);

        if (Rd < 15)
        {
                /* DCCRX to Rn, "MCR p14, 0, Rn, c0, c5, 0", 0xEE00nE15 */
                cortex_a8_exec_opcode(target, ARMV4_5_MRC(14, 0, Rd, 0, 5, 0),
                                &dscr);
        }
        else if (Rd == 15)
        {
                /* DCCRX to R0, "MCR p14, 0, R0, c0, c5, 0", 0xEE000E15
                 * then "mov r15, r0"
                 */
                cortex_a8_exec_opcode(target, ARMV4_5_MRC(14, 0, 0, 0, 5, 0),
                                &dscr);
                cortex_a8_exec_opcode(target, 0xE1A0F000, &dscr);
        }
        else
        {
                /* DCCRX to R0, "MCR p14, 0, R0, c0, c5, 0", 0xEE000E15
                 * then "MSR CPSR_cxsf, r0" or "MSR SPSR_cxsf, r0" (all fields)
                 */
                cortex_a8_exec_opcode(target, ARMV4_5_MRC(14, 0, 0, 0, 5, 0),
                                &dscr);
                cortex_a8_exec_opcode(target, ARMV4_5_MSR_GP(0, 0xF, Rd & 1),
                                &dscr);

                /* "Prefetch flush" after modifying execution status in CPSR */
                if (Rd == 16)
                        cortex_a8_exec_opcode(target,
                                        ARMV4_5_MCR(15, 0, 0, 7, 5, 4),
                                        &dscr);
        }

        return retval;
}

/* Write to memory mapped registers directly with no cache or mmu handling */
static int cortex_a8_dap_write_memap_register_u32(struct target *target, uint32_t address, uint32_t value)
{
        int retval;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        retval = mem_ap_write_atomic_u32(swjdp, address, value);

        return retval;
}

/*
 * Cortex-A8 implementation of Debug Programmer's Model
 *
 * NOTE the invariant:  these routines return with DSCR_INSTR_COMP set,
 * so there's no need to poll for it before executing an instruction.
 *
 * NOTE that in several of these cases the "stall" mode might be useful.
 * It'd let us queue a few operations together... prepare/finish might
 * be the places to enable/disable that mode.
 */

static inline struct cortex_a8_common *dpm_to_a8(struct arm_dpm *dpm)
{
        return container_of(dpm, struct cortex_a8_common, armv7a_common.dpm);
}

static int cortex_a8_write_dcc(struct cortex_a8_common *a8, uint32_t data)
{
        LOG_DEBUG("write DCC 0x%08" PRIx32, data);
        return mem_ap_write_u32(&a8->armv7a_common.dap,
                        a8->armv7a_common.debug_base + CPUDBG_DTRRX, data);
}

static int cortex_a8_read_dcc(struct cortex_a8_common *a8, uint32_t *data,
                uint32_t *dscr_p)
{
        struct adiv5_dap *swjdp = &a8->armv7a_common.dap;
        uint32_t dscr = DSCR_INSTR_COMP;
        int retval;

        if (dscr_p)
                dscr = *dscr_p;

        /* Wait for DTRRXfull */
        while ((dscr & DSCR_DTR_TX_FULL) == 0) {
                retval = mem_ap_read_atomic_u32(swjdp,
                                a8->armv7a_common.debug_base + CPUDBG_DSCR,
                                &dscr);
                if (retval != ERROR_OK)
                        return retval;
        }

        retval = mem_ap_read_atomic_u32(swjdp,
                        a8->armv7a_common.debug_base + CPUDBG_DTRTX, data);
        if (retval != ERROR_OK)
                return retval;
        //LOG_DEBUG("read DCC 0x%08" PRIx32, *data);

        if (dscr_p)
                *dscr_p = dscr;

        return retval;
}

static int cortex_a8_dpm_prepare(struct arm_dpm *dpm)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        struct adiv5_dap *swjdp = &a8->armv7a_common.dap;
        uint32_t dscr;
        int retval;

        /* set up invariant:  INSTR_COMP is set after ever DPM operation */
        long long then = timeval_ms();
        for (;;)
        {
                retval = mem_ap_read_atomic_u32(swjdp,
                                a8->armv7a_common.debug_base + CPUDBG_DSCR,
                                &dscr);
                if (retval != ERROR_OK)
                        return retval;
                if ((dscr & DSCR_INSTR_COMP) != 0)
                        break;
                if (timeval_ms() > then + 1000)
                {
                        LOG_ERROR("Timeout waiting for dpm prepare");
                        return ERROR_FAIL;
                }
        }

        /* this "should never happen" ... */
        if (dscr & DSCR_DTR_RX_FULL) {
                LOG_ERROR("DSCR_DTR_RX_FULL, dscr 0x%08" PRIx32, dscr);
                /* Clear DCCRX */
                retval = cortex_a8_exec_opcode(
                                a8->armv7a_common.armv4_5_common.target,
                                ARMV4_5_MRC(14, 0, 0, 0, 5, 0),
                                &dscr);
        }

        return retval;
}

static int cortex_a8_dpm_finish(struct arm_dpm *dpm)
{
        /* REVISIT what could be done here? */
        return ERROR_OK;
}

static int cortex_a8_instr_write_data_dcc(struct arm_dpm *dpm,
                uint32_t opcode, uint32_t data)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        int retval;
        uint32_t dscr = DSCR_INSTR_COMP;

        retval = cortex_a8_write_dcc(a8, data);

        return cortex_a8_exec_opcode(
                        a8->armv7a_common.armv4_5_common.target,
                        opcode,
                        &dscr);
}

static int cortex_a8_instr_write_data_r0(struct arm_dpm *dpm,
                uint32_t opcode, uint32_t data)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        uint32_t dscr = DSCR_INSTR_COMP;
        int retval;

        retval = cortex_a8_write_dcc(a8, data);

        /* DCCRX to R0, "MCR p14, 0, R0, c0, c5, 0", 0xEE000E15 */
        retval = cortex_a8_exec_opcode(
                        a8->armv7a_common.armv4_5_common.target,
                        ARMV4_5_MRC(14, 0, 0, 0, 5, 0),
                        &dscr);

        /* then the opcode, taking data from R0 */
        retval = cortex_a8_exec_opcode(
                        a8->armv7a_common.armv4_5_common.target,
                        opcode,
                        &dscr);

        return retval;
}

static int cortex_a8_instr_cpsr_sync(struct arm_dpm *dpm)
{
        struct target *target = dpm->arm->target;
        uint32_t dscr = DSCR_INSTR_COMP;

        /* "Prefetch flush" after modifying execution status in CPSR */
        return cortex_a8_exec_opcode(target,
                        ARMV4_5_MCR(15, 0, 0, 7, 5, 4),
                        &dscr);
}

static int cortex_a8_instr_read_data_dcc(struct arm_dpm *dpm,
                uint32_t opcode, uint32_t *data)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        int retval;
        uint32_t dscr = DSCR_INSTR_COMP;

        /* the opcode, writing data to DCC */
        retval = cortex_a8_exec_opcode(
                        a8->armv7a_common.armv4_5_common.target,
                        opcode,
                        &dscr);

        return cortex_a8_read_dcc(a8, data, &dscr);
}


static int cortex_a8_instr_read_data_r0(struct arm_dpm *dpm,
                uint32_t opcode, uint32_t *data)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        uint32_t dscr = DSCR_INSTR_COMP;
        int retval;

        /* the opcode, writing data to R0 */
        retval = cortex_a8_exec_opcode(
                        a8->armv7a_common.armv4_5_common.target,
                        opcode,
                        &dscr);

        /* write R0 to DCC */
        retval = cortex_a8_exec_opcode(
                        a8->armv7a_common.armv4_5_common.target,
                        ARMV4_5_MCR(14, 0, 0, 0, 5, 0),
                        &dscr);

        return cortex_a8_read_dcc(a8, data, &dscr);
}

static int cortex_a8_bpwp_enable(struct arm_dpm *dpm, unsigned index_t,
                uint32_t addr, uint32_t control)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        uint32_t vr = a8->armv7a_common.debug_base;
        uint32_t cr = a8->armv7a_common.debug_base;
        int retval;

        switch (index_t) {
        case 0 ... 15:          /* breakpoints */
                vr += CPUDBG_BVR_BASE;
                cr += CPUDBG_BCR_BASE;
                break;
        case 16 ... 31:         /* watchpoints */
                vr += CPUDBG_WVR_BASE;
                cr += CPUDBG_WCR_BASE;
                index_t -= 16;
                break;
        default:
                return ERROR_FAIL;
        }
        vr += 4 * index_t;
        cr += 4 * index_t;

        LOG_DEBUG("A8: bpwp enable, vr %08x cr %08x",
                        (unsigned) vr, (unsigned) cr);

        retval = cortex_a8_dap_write_memap_register_u32(dpm->arm->target,
                        vr, addr);
        if (retval != ERROR_OK)
                return retval;
        retval = cortex_a8_dap_write_memap_register_u32(dpm->arm->target,
                        cr, control);
        return retval;
}

static int cortex_a8_bpwp_disable(struct arm_dpm *dpm, unsigned index_t)
{
        struct cortex_a8_common *a8 = dpm_to_a8(dpm);
        uint32_t cr;

        switch (index_t) {
        case 0 ... 15:
                cr = a8->armv7a_common.debug_base + CPUDBG_BCR_BASE;
                break;
        case 16 ... 31:
                cr = a8->armv7a_common.debug_base + CPUDBG_WCR_BASE;
                index_t -= 16;
                break;
        default:
                return ERROR_FAIL;
        }
        cr += 4 * index_t;

        LOG_DEBUG("A8: bpwp disable, cr %08x", (unsigned) cr);

        /* clear control register */
        return cortex_a8_dap_write_memap_register_u32(dpm->arm->target, cr, 0);
}

static int cortex_a8_dpm_setup(struct cortex_a8_common *a8, uint32_t didr)
{
        struct arm_dpm *dpm = &a8->armv7a_common.dpm;
        int retval;

        dpm->arm = &a8->armv7a_common.armv4_5_common;
        dpm->didr = didr;

        dpm->prepare = cortex_a8_dpm_prepare;
        dpm->finish = cortex_a8_dpm_finish;

        dpm->instr_write_data_dcc = cortex_a8_instr_write_data_dcc;
        dpm->instr_write_data_r0 = cortex_a8_instr_write_data_r0;
        dpm->instr_cpsr_sync = cortex_a8_instr_cpsr_sync;

        dpm->instr_read_data_dcc = cortex_a8_instr_read_data_dcc;
        dpm->instr_read_data_r0 = cortex_a8_instr_read_data_r0;

        dpm->bpwp_enable = cortex_a8_bpwp_enable;
        dpm->bpwp_disable = cortex_a8_bpwp_disable;

        retval = arm_dpm_setup(dpm);
        if (retval == ERROR_OK)
                retval = arm_dpm_initialize(dpm);

        return retval;
}


/*
 * Cortex-A8 Run control
 */

static int cortex_a8_poll(struct target *target)
{
        int retval = ERROR_OK;
        uint32_t dscr;
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        struct adiv5_dap *swjdp = &armv7a->dap;
        enum target_state prev_target_state = target->state;
        uint8_t saved_apsel = dap_ap_get_select(swjdp);

        dap_ap_select(swjdp, swjdp_debugap);
        retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DSCR, &dscr);
        if (retval != ERROR_OK)
        {
                dap_ap_select(swjdp, saved_apsel);
                return retval;
        }
        cortex_a8->cpudbg_dscr = dscr;

        if ((dscr & 0x3) == 0x3)
        {
                if (prev_target_state != TARGET_HALTED)
                {
                        /* We have a halting debug event */
                        LOG_DEBUG("Target halted");
                        target->state = TARGET_HALTED;
                        if ((prev_target_state == TARGET_RUNNING)
                                        || (prev_target_state == TARGET_RESET))
                        {
                                retval = cortex_a8_debug_entry(target);
                                if (retval != ERROR_OK)
                                        return retval;

                                target_call_event_callbacks(target,
                                                TARGET_EVENT_HALTED);
                        }
                        if (prev_target_state == TARGET_DEBUG_RUNNING)
                        {
                                LOG_DEBUG(" ");

                                retval = cortex_a8_debug_entry(target);
                                if (retval != ERROR_OK)
                                        return retval;

                                target_call_event_callbacks(target,
                                                TARGET_EVENT_DEBUG_HALTED);
                        }
                }
        }
        else if ((dscr & 0x3) == 0x2)
        {
                target->state = TARGET_RUNNING;
        }
        else
        {
                LOG_DEBUG("Unknown target state dscr = 0x%08" PRIx32, dscr);
                target->state = TARGET_UNKNOWN;
        }

        dap_ap_select(swjdp, saved_apsel);

        return retval;
}

static int cortex_a8_halt(struct target *target)
{
        int retval = ERROR_OK;
        uint32_t dscr;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;
        uint8_t saved_apsel = dap_ap_get_select(swjdp);
        dap_ap_select(swjdp, swjdp_debugap);

        /*
         * Tell the core to be halted by writing DRCR with 0x1
         * and then wait for the core to be halted.
         */
        retval = mem_ap_write_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DRCR, 0x1);
        if (retval != ERROR_OK)
                goto out;

        /*
         * enter halting debug mode
         */
        retval = mem_ap_read_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_DSCR, &dscr);
        if (retval != ERROR_OK)
                goto out;

        retval = mem_ap_write_atomic_u32(swjdp,
                armv7a->debug_base + CPUDBG_DSCR, dscr | DSCR_HALT_DBG_MODE);
        if (retval != ERROR_OK)
                goto out;

        long long then = timeval_ms();
        for (;;)
        {
                retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DSCR, &dscr);
                if (retval != ERROR_OK)
                        goto out;
                if ((dscr & DSCR_CORE_HALTED) != 0)
                {
                        break;
                }
                if (timeval_ms() > then + 1000)
                {
                        LOG_ERROR("Timeout waiting for halt");
                        return ERROR_FAIL;
                }
        }

        target->debug_reason = DBG_REASON_DBGRQ;

out:
        dap_ap_select(swjdp, saved_apsel);
        return retval;
}

static int cortex_a8_resume(struct target *target, int current,
                uint32_t address, int handle_breakpoints, int debug_execution)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct arm *armv4_5 = &armv7a->armv4_5_common;
        struct adiv5_dap *swjdp = &armv7a->dap;
        int retval;

//      struct breakpoint *breakpoint = NULL;
        uint32_t resume_pc, dscr;

        uint8_t saved_apsel = dap_ap_get_select(swjdp);
        dap_ap_select(swjdp, swjdp_debugap);

        if (!debug_execution)
                target_free_all_working_areas(target);

#if 0
        if (debug_execution)
        {
                /* Disable interrupts */
                /* We disable interrupts in the PRIMASK register instead of
                 * masking with C_MASKINTS,
                 * This is probably the same issue as Cortex-M3 Errata 377493:
                 * C_MASKINTS in parallel with disabled interrupts can cause
                 * local faults to not be taken. */
                buf_set_u32(armv7m->core_cache->reg_list[ARMV7M_PRIMASK].value, 0, 32, 1);
                armv7m->core_cache->reg_list[ARMV7M_PRIMASK].dirty = 1;
                armv7m->core_cache->reg_list[ARMV7M_PRIMASK].valid = 1;

                /* Make sure we are in Thumb mode */
                buf_set_u32(armv7m->core_cache->reg_list[ARMV7M_xPSR].value, 0, 32,
                        buf_get_u32(armv7m->core_cache->reg_list[ARMV7M_xPSR].value, 0, 32) | (1 << 24));
                armv7m->core_cache->reg_list[ARMV7M_xPSR].dirty = 1;
                armv7m->core_cache->reg_list[ARMV7M_xPSR].valid = 1;
        }
#endif

        /* current = 1: continue on current pc, otherwise continue at <address> */
        resume_pc = buf_get_u32(armv4_5->pc->value, 0, 32);
        if (!current)
                resume_pc = address;

        /* Make sure that the Armv7 gdb thumb fixups does not
         * kill the return address
         */
        switch (armv4_5->core_state)
        {
        case ARM_STATE_ARM:
                resume_pc &= 0xFFFFFFFC;
                break;
        case ARM_STATE_THUMB:
        case ARM_STATE_THUMB_EE:
                /* When the return address is loaded into PC
                 * bit 0 must be 1 to stay in Thumb state
                 */
                resume_pc |= 0x1;
                break;
        case ARM_STATE_JAZELLE:
                LOG_ERROR("How do I resume into Jazelle state??");
                return ERROR_FAIL;
        }
        LOG_DEBUG("resume pc = 0x%08" PRIx32, resume_pc);
        buf_set_u32(armv4_5->pc->value, 0, 32, resume_pc);
        armv4_5->pc->dirty = 1;
        armv4_5->pc->valid = 1;

        cortex_a8_restore_context(target, handle_breakpoints);

#if 0
        /* the front-end may request us not to handle breakpoints */
        if (handle_breakpoints)
        {
                /* Single step past breakpoint at current address */
                if ((breakpoint = breakpoint_find(target, resume_pc)))
                {
                        LOG_DEBUG("unset breakpoint at 0x%8.8x", breakpoint->address);
                        cortex_m3_unset_breakpoint(target, breakpoint);
                        cortex_m3_single_step_core(target);
                        cortex_m3_set_breakpoint(target, breakpoint);
                }
        }

#endif
        /* Restart core and wait for it to be started
         * NOTE: this clears DSCR_ITR_EN and other bits.
         *
         * REVISIT: for single stepping, we probably want to
         * disable IRQs by default, with optional override...
         */
        retval = mem_ap_write_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_DRCR, 0x2);
        if (retval != ERROR_OK)
                return retval;

        long long then = timeval_ms();
        for (;;)
        {
                retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DSCR, &dscr);
                if (retval != ERROR_OK)
                        return retval;
                if ((dscr & DSCR_CORE_RESTARTED) != 0)
                        break;
                if (timeval_ms() > then + 1000)
                {
                        LOG_ERROR("Timeout waiting for resume");
                        return ERROR_FAIL;
                }
        }

        target->debug_reason = DBG_REASON_NOTHALTED;
        target->state = TARGET_RUNNING;

        /* registers are now invalid */
        register_cache_invalidate(armv4_5->core_cache);

        if (!debug_execution)
        {
                target->state = TARGET_RUNNING;
                target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
                LOG_DEBUG("target resumed at 0x%" PRIx32, resume_pc);
        }
        else
        {
                target->state = TARGET_DEBUG_RUNNING;
                target_call_event_callbacks(target, TARGET_EVENT_DEBUG_RESUMED);
                LOG_DEBUG("target debug resumed at 0x%" PRIx32, resume_pc);
        }

        dap_ap_select(swjdp, saved_apsel);

        return ERROR_OK;
}

static int cortex_a8_debug_entry(struct target *target)
{
        int i;
        uint32_t regfile[16], cpsr, dscr;
        int retval = ERROR_OK;
        struct working_area *regfile_working_area = NULL;
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct arm *armv4_5 = &armv7a->armv4_5_common;
        struct adiv5_dap *swjdp = &armv7a->dap;
        struct reg *reg;

        LOG_DEBUG("dscr = 0x%08" PRIx32, cortex_a8->cpudbg_dscr);

        /* REVISIT surely we should not re-read DSCR !! */
        retval = mem_ap_read_atomic_u32(swjdp,
                                armv7a->debug_base + CPUDBG_DSCR, &dscr);
        if (retval != ERROR_OK)
                return retval;

        /* REVISIT see A8 TRM 12.11.4 steps 2..3 -- make sure that any
         * imprecise data aborts get discarded by issuing a Data
         * Synchronization Barrier:  ARMV4_5_MCR(15, 0, 0, 7, 10, 4).
         */

        /* Enable the ITR execution once we are in debug mode */
        dscr |= DSCR_ITR_EN;
        retval = mem_ap_write_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DSCR, dscr);
        if (retval != ERROR_OK)
                return retval;

        /* Examine debug reason */
        arm_dpm_report_dscr(&armv7a->dpm, cortex_a8->cpudbg_dscr);

        /* save address of instruction that triggered the watchpoint? */
        if (target->debug_reason == DBG_REASON_WATCHPOINT) {
                uint32_t wfar;

                retval = mem_ap_read_atomic_u32(swjdp,
                                armv7a->debug_base + CPUDBG_WFAR,
                                &wfar);
                if (retval != ERROR_OK)
                        return retval;
                arm_dpm_report_wfar(&armv7a->dpm, wfar);
        }

        /* REVISIT fast_reg_read is never set ... */

        /* Examine target state and mode */
        if (cortex_a8->fast_reg_read)
                target_alloc_working_area(target, 64, &regfile_working_area);

        /* First load register acessible through core debug port*/
        if (!regfile_working_area)
        {
                retval = arm_dpm_read_current_registers(&armv7a->dpm);
        }
        else
        {
                dap_ap_select(swjdp, swjdp_memoryap);
                cortex_a8_read_regs_through_mem(target,
                                regfile_working_area->address, regfile);
                dap_ap_select(swjdp, swjdp_memoryap);
                target_free_working_area(target, regfile_working_area);

                /* read Current PSR */
                cortex_a8_dap_read_coreregister_u32(target, &cpsr, 16);
                dap_ap_select(swjdp, swjdp_debugap);
                LOG_DEBUG("cpsr: %8.8" PRIx32, cpsr);

                arm_set_cpsr(armv4_5, cpsr);

                /* update cache */
                for (i = 0; i <= ARM_PC; i++)
                {
                        reg = arm_reg_current(armv4_5, i);

                        buf_set_u32(reg->value, 0, 32, regfile[i]);
                        reg->valid = 1;
                        reg->dirty = 0;
                }

                /* Fixup PC Resume Address */
                if (cpsr & (1 << 5))
                {
                        // T bit set for Thumb or ThumbEE state
                        regfile[ARM_PC] -= 4;
                }
                else
                {
                        // ARM state
                        regfile[ARM_PC] -= 8;
                }

                reg = armv4_5->pc;
                buf_set_u32(reg->value, 0, 32, regfile[ARM_PC]);
                reg->dirty = reg->valid;
        }

#if 0
/* TODO, Move this */
        uint32_t cp15_control_register, cp15_cacr, cp15_nacr;
        cortex_a8_read_cp(target, &cp15_control_register, 15, 0, 1, 0, 0);
        LOG_DEBUG("cp15_control_register = 0x%08x", cp15_control_register);

        cortex_a8_read_cp(target, &cp15_cacr, 15, 0, 1, 0, 2);
        LOG_DEBUG("cp15 Coprocessor Access Control Register = 0x%08x", cp15_cacr);

        cortex_a8_read_cp(target, &cp15_nacr, 15, 0, 1, 1, 2);
        LOG_DEBUG("cp15 Nonsecure Access Control Register = 0x%08x", cp15_nacr);
#endif

        /* Are we in an exception handler */
//      armv4_5->exception_number = 0;
        if (armv7a->post_debug_entry)
                armv7a->post_debug_entry(target);

        return retval;
}

static void cortex_a8_post_debug_entry(struct target *target)
{
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        int retval;

        /* MRC p15,0,<Rt>,c1,c0,0 ; Read CP15 System Control Register */
        retval = armv7a->armv4_5_common.mrc(target, 15,
                        0, 0,   /* op1, op2 */
                        1, 0,   /* CRn, CRm */
                        &cortex_a8->cp15_control_reg);
        LOG_DEBUG("cp15_control_reg: %8.8" PRIx32, cortex_a8->cp15_control_reg);

        if (armv7a->armv4_5_mmu.armv4_5_cache.ctype == -1)
        {
                uint32_t cache_type_reg;

                /* MRC p15,0,<Rt>,c0,c0,1 ; Read CP15 Cache Type Register */
                retval = armv7a->armv4_5_common.mrc(target, 15,
                                0, 1,   /* op1, op2 */
                                0, 0,   /* CRn, CRm */
                                &cache_type_reg);
                LOG_DEBUG("cp15 cache type: %8.8x", (unsigned) cache_type_reg);

                /* FIXME the armv4_4 cache info DOES NOT APPLY to Cortex-A8 */
                armv4_5_identify_cache(cache_type_reg,
                                &armv7a->armv4_5_mmu.armv4_5_cache);
        }

        armv7a->armv4_5_mmu.mmu_enabled =
                        (cortex_a8->cp15_control_reg & 0x1U) ? 1 : 0;
        armv7a->armv4_5_mmu.armv4_5_cache.d_u_cache_enabled =
                        (cortex_a8->cp15_control_reg & 0x4U) ? 1 : 0;
        armv7a->armv4_5_mmu.armv4_5_cache.i_cache_enabled =
                        (cortex_a8->cp15_control_reg & 0x1000U) ? 1 : 0;


}

static int cortex_a8_step(struct target *target, int current, uint32_t address,
                int handle_breakpoints)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct arm *armv4_5 = &armv7a->armv4_5_common;
        struct breakpoint *breakpoint = NULL;
        struct breakpoint stepbreakpoint;
        struct reg *r;
        int retval;

        int timeout = 100;

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

        /* current = 1: continue on current pc, otherwise continue at <address> */
        r = armv4_5->pc;
        if (!current)
        {
                buf_set_u32(r->value, 0, 32, address);
        }
        else
        {
                address = buf_get_u32(r->value, 0, 32);
        }

        /* The front-end may request us not to handle breakpoints.
         * But since Cortex-A8 uses breakpoint for single step,
         * we MUST handle breakpoints.
         */
        handle_breakpoints = 1;
        if (handle_breakpoints) {
                breakpoint = breakpoint_find(target, address);
                if (breakpoint)
                        cortex_a8_unset_breakpoint(target, breakpoint);
        }

        /* Setup single step breakpoint */
        stepbreakpoint.address = address;
        stepbreakpoint.length = (armv4_5->core_state == ARM_STATE_THUMB)
                        ? 2 : 4;
        stepbreakpoint.type = BKPT_HARD;
        stepbreakpoint.set = 0;

        /* Break on IVA mismatch */
        cortex_a8_set_breakpoint(target, &stepbreakpoint, 0x04);

        target->debug_reason = DBG_REASON_SINGLESTEP;

        retval = cortex_a8_resume(target, 1, address, 0, 0);
        if (retval != ERROR_OK)
                return retval;

        while (target->state != TARGET_HALTED)
        {
                retval = cortex_a8_poll(target);
                if (retval != ERROR_OK)
                        return retval;
                if (--timeout == 0)
                {
                        LOG_ERROR("timeout waiting for target halt");
                        return ERROR_FAIL;
                }
        }

        cortex_a8_unset_breakpoint(target, &stepbreakpoint);
        if (timeout > 0)
                target->debug_reason = DBG_REASON_BREAKPOINT;

        if (breakpoint)
                cortex_a8_set_breakpoint(target, breakpoint, 0);

        if (target->state != TARGET_HALTED)
                LOG_DEBUG("target stepped");

        return ERROR_OK;
}

static int cortex_a8_restore_context(struct target *target, bool bpwp)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);

        LOG_DEBUG(" ");

        if (armv7a->pre_restore_context)
                armv7a->pre_restore_context(target);

        arm_dpm_write_dirty_registers(&armv7a->dpm, bpwp);

        return ERROR_OK;
}


/*
 * Cortex-A8 Breakpoint and watchpoint functions
 */

/* Setup hardware Breakpoint Register Pair */
static int cortex_a8_set_breakpoint(struct target *target,
                struct breakpoint *breakpoint, uint8_t matchmode)
{
        int retval;
        int brp_i=0;
        uint32_t control;
        uint8_t byte_addr_select = 0x0F;
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        struct cortex_a8_brp * brp_list = cortex_a8->brp_list;

        if (breakpoint->set)
        {
                LOG_WARNING("breakpoint already set");
                return ERROR_OK;
        }

        if (breakpoint->type == BKPT_HARD)
        {
                while (brp_list[brp_i].used && (brp_i < cortex_a8->brp_num))
                        brp_i++ ;
                if (brp_i >= cortex_a8->brp_num)
                {
                        LOG_ERROR("ERROR Can not find free Breakpoint Register Pair");
                        return ERROR_FAIL;
                }
                breakpoint->set = brp_i + 1;
                if (breakpoint->length == 2)
                {
                        byte_addr_select = (3 << (breakpoint->address & 0x02));
                }
                control = ((matchmode & 0x7) << 20)
                                | (byte_addr_select << 5)
                                | (3 << 1) | 1;
                brp_list[brp_i].used = 1;
                brp_list[brp_i].value = (breakpoint->address & 0xFFFFFFFC);
                brp_list[brp_i].control = control;
                cortex_a8_dap_write_memap_register_u32(target, armv7a->debug_base
                                + CPUDBG_BVR_BASE + 4 * brp_list[brp_i].BRPn,
                                brp_list[brp_i].value);
                cortex_a8_dap_write_memap_register_u32(target, armv7a->debug_base
                                + CPUDBG_BCR_BASE + 4 * brp_list[brp_i].BRPn,
                                brp_list[brp_i].control);
                LOG_DEBUG("brp %i control 0x%0" PRIx32 " value 0x%0" PRIx32, brp_i,
                                brp_list[brp_i].control,
                                brp_list[brp_i].value);
        }
        else if (breakpoint->type == BKPT_SOFT)
        {
                uint8_t code[4];
                if (breakpoint->length == 2)
                {
                        buf_set_u32(code, 0, 32, ARMV5_T_BKPT(0x11));
                }
                else
                {
                        buf_set_u32(code, 0, 32, ARMV5_BKPT(0x11));
                }
                retval = target->type->read_memory(target,
                                breakpoint->address & 0xFFFFFFFE,
                                breakpoint->length, 1,
                                breakpoint->orig_instr);
                if (retval != ERROR_OK)
                        return retval;
                retval = target->type->write_memory(target,
                                breakpoint->address & 0xFFFFFFFE,
                                breakpoint->length, 1, code);
                if (retval != ERROR_OK)
                        return retval;
                breakpoint->set = 0x11; /* Any nice value but 0 */
        }

        return ERROR_OK;
}

static int cortex_a8_unset_breakpoint(struct target *target, struct breakpoint *breakpoint)
{
        int retval;
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        struct cortex_a8_brp * brp_list = cortex_a8->brp_list;

        if (!breakpoint->set)
        {
                LOG_WARNING("breakpoint not set");
                return ERROR_OK;
        }

        if (breakpoint->type == BKPT_HARD)
        {
                int brp_i = breakpoint->set - 1;
                if ((brp_i < 0) || (brp_i >= cortex_a8->brp_num))
                {
                        LOG_DEBUG("Invalid BRP number in breakpoint");
                        return ERROR_OK;
                }
                LOG_DEBUG("rbp %i control 0x%0" PRIx32 " value 0x%0" PRIx32, brp_i,
                                brp_list[brp_i].control, brp_list[brp_i].value);
                brp_list[brp_i].used = 0;
                brp_list[brp_i].value = 0;
                brp_list[brp_i].control = 0;
                cortex_a8_dap_write_memap_register_u32(target, armv7a->debug_base
                                + CPUDBG_BCR_BASE + 4 * brp_list[brp_i].BRPn,
                                brp_list[brp_i].control);
                cortex_a8_dap_write_memap_register_u32(target, armv7a->debug_base
                                + CPUDBG_BVR_BASE + 4 * brp_list[brp_i].BRPn,
                                brp_list[brp_i].value);
        }
        else
        {
                /* restore original instruction (kept in target endianness) */
                if (breakpoint->length == 4)
                {
                        retval = target->type->write_memory(target,
                                        breakpoint->address & 0xFFFFFFFE,
                                        4, 1, breakpoint->orig_instr);
                        if (retval != ERROR_OK)
                                return retval;
                }
                else
                {
                        retval = target->type->write_memory(target,
                                        breakpoint->address & 0xFFFFFFFE,
                                        2, 1, breakpoint->orig_instr);
                        if (retval != ERROR_OK)
                                return retval;
                }
        }
        breakpoint->set = 0;

        return ERROR_OK;
}

static int cortex_a8_add_breakpoint(struct target *target,
                struct breakpoint *breakpoint)
{
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);

        if ((breakpoint->type == BKPT_HARD) && (cortex_a8->brp_num_available < 1))
        {
                LOG_INFO("no hardware breakpoint available");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        if (breakpoint->type == BKPT_HARD)
                cortex_a8->brp_num_available--;
        cortex_a8_set_breakpoint(target, breakpoint, 0x00); /* Exact match */

        return ERROR_OK;
}

static int cortex_a8_remove_breakpoint(struct target *target, struct breakpoint *breakpoint)
{
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);

#if 0
/* It is perfectly possible to remove breakpoints while the target is running */
        if (target->state != TARGET_HALTED)
        {
                LOG_WARNING("target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }
#endif

        if (breakpoint->set)
        {
                cortex_a8_unset_breakpoint(target, breakpoint);
                if (breakpoint->type == BKPT_HARD)
                        cortex_a8->brp_num_available++ ;
        }


        return ERROR_OK;
}



/*
 * Cortex-A8 Reset functions
 */

static int cortex_a8_assert_reset(struct target *target)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);

        LOG_DEBUG(" ");

        /* FIXME when halt is requested, make it work somehow... */

        /* Issue some kind of warm reset. */
        if (target_has_event_action(target, TARGET_EVENT_RESET_ASSERT)) {
                target_handle_event(target, TARGET_EVENT_RESET_ASSERT);
        } else if (jtag_get_reset_config() & RESET_HAS_SRST) {
                /* REVISIT handle "pulls" cases, if there's
                 * hardware that needs them to work.
                 */
                jtag_add_reset(0, 1);
        } else {
                LOG_ERROR("%s: how to reset?", target_name(target));
                return ERROR_FAIL;
        }

        /* registers are now invalid */
        register_cache_invalidate(armv7a->armv4_5_common.core_cache);

        target->state = TARGET_RESET;

        return ERROR_OK;
}

static int cortex_a8_deassert_reset(struct target *target)
{
        int retval;

        LOG_DEBUG(" ");

        /* be certain SRST is off */
        jtag_add_reset(0, 0);

        retval = cortex_a8_poll(target);
        if (retval != ERROR_OK)
                return retval;

        if (target->reset_halt) {
                if (target->state != TARGET_HALTED) {
                        LOG_WARNING("%s: ran after reset and before halt ...",
                                        target_name(target));
                        if ((retval = target_halt(target)) != ERROR_OK)
                                return retval;
                }
        }

        return ERROR_OK;
}

/*
 * Cortex-A8 Memory access
 *
 * This is same Cortex M3 but we must also use the correct
 * ap number for every access.
 */

static int cortex_a8_read_phys_memory(struct target *target,
                uint32_t address, uint32_t size,
                uint32_t count, uint8_t *buffer)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;
        int retval = ERROR_INVALID_ARGUMENTS;

        /* cortex_a8 handles unaligned memory access */

// ???  dap_ap_select(swjdp, swjdp_memoryap);
        LOG_DEBUG("Reading memory at real address 0x%x; size %d; count %d", address, size, count);
        if (count && buffer) {
                switch (size) {
                case 4:
                        retval = mem_ap_read_buf_u32(swjdp, buffer, 4 * count, address);
                        break;
                case 2:
                        retval = mem_ap_read_buf_u16(swjdp, buffer, 2 * count, address);
                        break;
                case 1:
                        retval = mem_ap_read_buf_u8(swjdp, buffer, count, address);
                        break;
                }
        }

        return retval;
}

static int cortex_a8_read_memory(struct target *target, uint32_t address,
                uint32_t size, uint32_t count, uint8_t *buffer)
{
        int enabled = 0;
        uint32_t virt, phys;
        int retval;

        /* cortex_a8 handles unaligned memory access */

// ???  dap_ap_select(swjdp, swjdp_memoryap);
        LOG_DEBUG("Reading memory at address 0x%x; size %d; count %d", address, size, count);
        retval = cortex_a8_mmu(target, &enabled);
        if (retval != ERROR_OK)
                return retval;

        if(enabled)
        {
            virt = address;
            cortex_a8_virt2phys(target, virt, &phys);
            LOG_DEBUG("Reading at virtual address. Translating v:0x%x to r:0x%x", virt, phys);
            address = phys;
        }

        return cortex_a8_read_phys_memory(target, address, size, count, buffer);
}

static int cortex_a8_write_phys_memory(struct target *target,
                uint32_t address, uint32_t size,
                uint32_t count, uint8_t *buffer)
{
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;
        int retval = ERROR_INVALID_ARGUMENTS;

// ???  dap_ap_select(swjdp, swjdp_memoryap);

        LOG_DEBUG("Writing memory to real address 0x%x; size %d; count %d", address, size, count);
        if (count && buffer) {
                switch (size) {
                case 4:
                        retval = mem_ap_write_buf_u32(swjdp, buffer, 4 * count, address);
                        break;
                case 2:
                        retval = mem_ap_write_buf_u16(swjdp, buffer, 2 * count, address);
                        break;
                case 1:
                        retval = mem_ap_write_buf_u8(swjdp, buffer, count, address);
                        break;
                }
        }

        /* REVISIT this op is generic ARMv7-A/R stuff */
        if (retval == ERROR_OK && target->state == TARGET_HALTED)
        {
                struct arm_dpm *dpm = armv7a->armv4_5_common.dpm;

                retval = dpm->prepare(dpm);
                if (retval != ERROR_OK)
                        return retval;

                /* The Cache handling will NOT work with MMU active, the
                 * wrong addresses will be invalidated!
                 *
                 * For both ICache and DCache, walk all cache lines in the
                 * address range. Cortex-A8 has fixed 64 byte line length.
                 *
                 * REVISIT per ARMv7, these may trigger watchpoints ...
                 */

                /* invalidate I-Cache */
                if (armv7a->armv4_5_mmu.armv4_5_cache.i_cache_enabled)
                {
                        /* ICIMVAU - Invalidate Cache single entry
                         * with MVA to PoU
                         *      MCR p15, 0, r0, c7, c5, 1
                         */
                        for (uint32_t cacheline = address;
                                        cacheline < address + size * count;
                                        cacheline += 64) {
                                retval = dpm->instr_write_data_r0(dpm,
                                        ARMV4_5_MCR(15, 0, 0, 7, 5, 1),
                                        cacheline);
                        }
                }

                /* invalidate D-Cache */
                if (armv7a->armv4_5_mmu.armv4_5_cache.d_u_cache_enabled)
                {
                        /* DCIMVAC - Invalidate data Cache line
                         * with MVA to PoC
                         *      MCR p15, 0, r0, c7, c6, 1
                         */
                        for (uint32_t cacheline = address;
                                        cacheline < address + size * count;
                                        cacheline += 64) {
                                retval = dpm->instr_write_data_r0(dpm,
                                        ARMV4_5_MCR(15, 0, 0, 7, 6, 1),
                                        cacheline);
                        }
                }

                /* (void) */ dpm->finish(dpm);
        }

        return retval;
}

static int cortex_a8_write_memory(struct target *target, uint32_t address,
                uint32_t size, uint32_t count, uint8_t *buffer)
{
        int enabled = 0;
        uint32_t virt, phys;
        int retval;

// ???  dap_ap_select(swjdp, swjdp_memoryap);

        LOG_DEBUG("Writing memory to address 0x%x; size %d; count %d", address, size, count);
        retval = cortex_a8_mmu(target, &enabled);
        if (retval != ERROR_OK)
                return retval;
        if(enabled)
        {
            virt = address;
            cortex_a8_virt2phys(target, virt, &phys);
            LOG_DEBUG("Writing to virtual address. Translating v:0x%x to r:0x%x", virt, phys);
            address = phys;
        }

        return cortex_a8_write_phys_memory(target, address, size, 
                count, buffer);
}

static int cortex_a8_bulk_write_memory(struct target *target, uint32_t address,
                uint32_t count, uint8_t *buffer)
{
        return cortex_a8_write_memory(target, address, 4, count, buffer);
}


static int cortex_a8_dcc_read(struct adiv5_dap *swjdp, uint8_t *value, uint8_t *ctrl)
{
#if 0
        u16 dcrdr;

        mem_ap_read_buf_u16(swjdp, (uint8_t*)&dcrdr, 1, DCB_DCRDR);
        *ctrl = (uint8_t)dcrdr;
        *value = (uint8_t)(dcrdr >> 8);

        LOG_DEBUG("data 0x%x ctrl 0x%x", *value, *ctrl);

        /* write ack back to software dcc register
         * signify we have read data */
        if (dcrdr & (1 << 0))
        {
                dcrdr = 0;
                mem_ap_write_buf_u16(swjdp, (uint8_t*)&dcrdr, 1, DCB_DCRDR);
        }
#endif
        return ERROR_OK;
}


static int cortex_a8_handle_target_request(void *priv)
{
        struct target *target = priv;
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct adiv5_dap *swjdp = &armv7a->dap;

        if (!target_was_examined(target))
                return ERROR_OK;
        if (!target->dbg_msg_enabled)
                return ERROR_OK;

        if (target->state == TARGET_RUNNING)
        {
                uint8_t data = 0;
                uint8_t ctrl = 0;

                cortex_a8_dcc_read(swjdp, &data, &ctrl);

                /* check if we have data */
                if (ctrl & (1 << 0))
                {
                        uint32_t request;

                        /* we assume target is quick enough */
                        request = data;
                        cortex_a8_dcc_read(swjdp, &data, &ctrl);
                        request |= (data << 8);
                        cortex_a8_dcc_read(swjdp, &data, &ctrl);
                        request |= (data << 16);
                        cortex_a8_dcc_read(swjdp, &data, &ctrl);
                        request |= (data << 24);
                        target_request(target, request);
                }
        }

        return ERROR_OK;
}

/*
 * Cortex-A8 target information and configuration
 */

static int cortex_a8_examine_first(struct target *target)
{
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        struct adiv5_dap *swjdp = &armv7a->dap;
        int i;
        int retval = ERROR_OK;
        uint32_t didr, ctypr, ttypr, cpuid;

        /* stop assuming this is an OMAP! */
        LOG_DEBUG("TODO - autoconfigure");

        /* Here we shall insert a proper ROM Table scan */
        armv7a->debug_base = OMAP3530_DEBUG_BASE;

        /* We do one extra read to ensure DAP is configured,
         * we call ahbap_debugport_init(swjdp) instead
         */
        retval = ahbap_debugport_init(swjdp);
        if (retval != ERROR_OK)
                return retval;

        retval = mem_ap_read_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_CPUID, &cpuid);
        if (retval != ERROR_OK)
                return retval;

        if ((retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_CPUID, &cpuid)) != ERROR_OK)
        {
                LOG_DEBUG("Examine %s failed", "CPUID");
                return retval;
        }

        if ((retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_CTYPR, &ctypr)) != ERROR_OK)
        {
                LOG_DEBUG("Examine %s failed", "CTYPR");
                return retval;
        }

        if ((retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_TTYPR, &ttypr)) != ERROR_OK)
        {
                LOG_DEBUG("Examine %s failed", "TTYPR");
                return retval;
        }

        if ((retval = mem_ap_read_atomic_u32(swjdp,
                        armv7a->debug_base + CPUDBG_DIDR, &didr)) != ERROR_OK)
        {
                LOG_DEBUG("Examine %s failed", "DIDR");
                return retval;
        }

        LOG_DEBUG("cpuid = 0x%08" PRIx32, cpuid);
        LOG_DEBUG("ctypr = 0x%08" PRIx32, ctypr);
        LOG_DEBUG("ttypr = 0x%08" PRIx32, ttypr);
        LOG_DEBUG("didr = 0x%08" PRIx32, didr);

        armv7a->armv4_5_common.core_type = ARM_MODE_MON;
        retval = cortex_a8_dpm_setup(cortex_a8, didr);
        if (retval != ERROR_OK)
                return retval;

        /* Setup Breakpoint Register Pairs */
        cortex_a8->brp_num = ((didr >> 24) & 0x0F) + 1;
        cortex_a8->brp_num_context = ((didr >> 20) & 0x0F) + 1;
        cortex_a8->brp_num_available = cortex_a8->brp_num;
        cortex_a8->brp_list = calloc(cortex_a8->brp_num, sizeof(struct cortex_a8_brp));
//      cortex_a8->brb_enabled = ????;
        for (i = 0; i < cortex_a8->brp_num; i++)
        {
                cortex_a8->brp_list[i].used = 0;
                if (i < (cortex_a8->brp_num-cortex_a8->brp_num_context))
                        cortex_a8->brp_list[i].type = BRP_NORMAL;
                else
                        cortex_a8->brp_list[i].type = BRP_CONTEXT;
                cortex_a8->brp_list[i].value = 0;
                cortex_a8->brp_list[i].control = 0;
                cortex_a8->brp_list[i].BRPn = i;
        }

        LOG_DEBUG("Configured %i hw breakpoints", cortex_a8->brp_num);

        target_set_examined(target);
        return ERROR_OK;
}

static int cortex_a8_examine(struct target *target)
{
        int retval = ERROR_OK;

        /* don't re-probe hardware after each reset */
        if (!target_was_examined(target))
                retval = cortex_a8_examine_first(target);

        /* Configure core debug access */
        if (retval == ERROR_OK)
                retval = cortex_a8_init_debug_access(target);

        return retval;
}

/*
 *      Cortex-A8 target creation and initialization
 */

static int cortex_a8_init_target(struct command_context *cmd_ctx,
                struct target *target)
{
        /* examine_first() does a bunch of this */
        return ERROR_OK;
}

static int cortex_a8_init_arch_info(struct target *target,
                struct cortex_a8_common *cortex_a8, struct jtag_tap *tap)
{
        struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        struct arm *armv4_5 = &armv7a->armv4_5_common;
        struct adiv5_dap *dap = &armv7a->dap;

        armv7a->armv4_5_common.dap = dap;

        /* Setup struct cortex_a8_common */
        cortex_a8->common_magic = CORTEX_A8_COMMON_MAGIC;
        armv4_5->arch_info = armv7a;

        /* prepare JTAG information for the new target */
        cortex_a8->jtag_info.tap = tap;
        cortex_a8->jtag_info.scann_size = 4;

        /* Leave (only) generic DAP stuff for debugport_init() */
        dap->jtag_info = &cortex_a8->jtag_info;
        dap->memaccess_tck = 80;

        /* Number of bits for tar autoincrement, impl. dep. at least 10 */
        dap->tar_autoincr_block = (1 << 10);

        cortex_a8->fast_reg_read = 0;

        /* Set default value */
        cortex_a8->current_address_mode = ARM_MODE_ANY;

        /* register arch-specific functions */
        armv7a->examine_debug_reason = NULL;

        armv7a->post_debug_entry = cortex_a8_post_debug_entry;

        armv7a->pre_restore_context = NULL;
        armv7a->armv4_5_mmu.armv4_5_cache.ctype = -1;
        armv7a->armv4_5_mmu.get_ttb = cortex_a8_get_ttb;
        armv7a->armv4_5_mmu.read_memory = cortex_a8_read_phys_memory;
        armv7a->armv4_5_mmu.write_memory = cortex_a8_write_phys_memory;
        armv7a->armv4_5_mmu.disable_mmu_caches = cortex_a8_disable_mmu_caches;
        armv7a->armv4_5_mmu.enable_mmu_caches = cortex_a8_enable_mmu_caches;
        armv7a->armv4_5_mmu.has_tiny_pages = 1;
        armv7a->armv4_5_mmu.mmu_enabled = 0;


//      arm7_9->handle_target_request = cortex_a8_handle_target_request;

        /* REVISIT v7a setup should be in a v7a-specific routine */
        arm_init_arch_info(target, armv4_5);
        armv7a->common_magic = ARMV7_COMMON_MAGIC;

        target_register_timer_callback(cortex_a8_handle_target_request, 1, 1, target);

        return ERROR_OK;
}

static int cortex_a8_target_create(struct target *target, Jim_Interp *interp)
{
        struct cortex_a8_common *cortex_a8 = calloc(1, sizeof(struct cortex_a8_common));

        cortex_a8_init_arch_info(target, cortex_a8, target->tap);

        return ERROR_OK;
}

static uint32_t cortex_a8_get_ttb(struct target *target)
{
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
    struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
    uint32_t ttb = 0, retval = ERROR_OK;

    /* current_address_mode is set inside cortex_a8_virt2phys()
       where we can determine if address belongs to user or kernel */
    if(cortex_a8->current_address_mode == ARM_MODE_SVC)
    {
        /* MRC p15,0,<Rt>,c1,c0,0 ; Read CP15 System Control Register */
        retval = armv7a->armv4_5_common.mrc(target, 15,
                    0, 1,   /* op1, op2 */
                    2, 0,   /* CRn, CRm */
                    &ttb);
    }
    else if(cortex_a8->current_address_mode == ARM_MODE_USR)
    {
        /* MRC p15,0,<Rt>,c1,c0,0 ; Read CP15 System Control Register */
        retval = armv7a->armv4_5_common.mrc(target, 15,
                    0, 0,   /* op1, op2 */
                    2, 0,   /* CRn, CRm */
                    &ttb);
    }
    /* we don't know whose address is: user or kernel
       we assume that if we are in kernel mode then
       address belongs to kernel else if in user mode
       - to user */
    else if(armv7a->armv4_5_common.core_mode == ARM_MODE_SVC)
    {
        /* MRC p15,0,<Rt>,c1,c0,0 ; Read CP15 System Control Register */
        retval = armv7a->armv4_5_common.mrc(target, 15,
                    0, 1,   /* op1, op2 */
                    2, 0,   /* CRn, CRm */
                    &ttb);
    }
    else if(armv7a->armv4_5_common.core_mode == ARM_MODE_USR)
    {
        /* MRC p15,0,<Rt>,c1,c0,0 ; Read CP15 System Control Register */
        retval = armv7a->armv4_5_common.mrc(target, 15,
                    0, 0,   /* op1, op2 */
                    2, 0,   /* CRn, CRm */
                    &ttb);
    }
    /* finally we don't know whose ttb to use: user or kernel */
    else
        LOG_ERROR("Don't know how to get ttb for current mode!!!");

    ttb &= 0xffffc000;

    return ttb;
}

static void cortex_a8_disable_mmu_caches(struct target *target, int mmu,
                int d_u_cache, int i_cache)
{
    struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
    struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
    uint32_t cp15_control;

    /* read cp15 control register */
    armv7a->armv4_5_common.mrc(target, 15,
                    0, 0,   /* op1, op2 */
                    1, 0,   /* CRn, CRm */
                    &cp15_control);


    if (mmu)
            cp15_control &= ~0x1U;

    if (d_u_cache)
            cp15_control &= ~0x4U;

    if (i_cache)
            cp15_control &= ~0x1000U;

    armv7a->armv4_5_common.mcr(target, 15,
                    0, 0,   /* op1, op2 */
                    1, 0,   /* CRn, CRm */
                    cp15_control);
}

static void cortex_a8_enable_mmu_caches(struct target *target, int mmu,
                int d_u_cache, int i_cache)
{
    struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
    struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
    uint32_t cp15_control;

    /* read cp15 control register */
    armv7a->armv4_5_common.mrc(target, 15,
                    0, 0,   /* op1, op2 */
                    1, 0,   /* CRn, CRm */
                    &cp15_control);

    if (mmu)
            cp15_control |= 0x1U;

    if (d_u_cache)
            cp15_control |= 0x4U;

    if (i_cache)
            cp15_control |= 0x1000U;

    armv7a->armv4_5_common.mcr(target, 15,
                    0, 0,   /* op1, op2 */
                    1, 0,   /* CRn, CRm */
                    cp15_control);
}


static int cortex_a8_mmu(struct target *target, int *enabled)
{
        if (target->state != TARGET_HALTED) {
                LOG_ERROR("%s: target not halted", __func__);
                return ERROR_TARGET_INVALID;
        }

        *enabled = target_to_cortex_a8(target)->armv7a_common.armv4_5_mmu.mmu_enabled;
        return ERROR_OK;
}

static int cortex_a8_virt2phys(struct target *target,
                uint32_t virt, uint32_t *phys)
{
        uint32_t cb;
        struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
        // struct armv7a_common *armv7a = &cortex_a8->armv7a_common;
        struct armv7a_common *armv7a = target_to_armv7a(target);

    /* We assume that virtual address is separated
       between user and kernel in Linux style:
       0x00000000-0xbfffffff - User space
       0xc0000000-0xffffffff - Kernel space */
    if( virt < 0xc0000000 ) /* Linux user space */
        cortex_a8->current_address_mode = ARM_MODE_USR;
    else /* Linux kernel */
        cortex_a8->current_address_mode = ARM_MODE_SVC;
        uint32_t ret;
        int retval = armv4_5_mmu_translate_va(target,
                        &armv7a->armv4_5_mmu, virt, &cb, &ret);
        if (retval != ERROR_OK)
                return retval;
    /* Reset the flag. We don't want someone else to use it by error */
    cortex_a8->current_address_mode = ARM_MODE_ANY;

        *phys = ret;
        return ERROR_OK;
}

COMMAND_HANDLER(cortex_a8_handle_cache_info_command)
{
        struct target *target = get_current_target(CMD_CTX);
        struct armv7a_common *armv7a = target_to_armv7a(target);

        return armv4_5_handle_cache_info_command(CMD_CTX,
                        &armv7a->armv4_5_mmu.armv4_5_cache);
}


COMMAND_HANDLER(cortex_a8_handle_dbginit_command)
{
        struct target *target = get_current_target(CMD_CTX);
        if (!target_was_examined(target))
        {
                LOG_ERROR("target not examined yet");
                return ERROR_FAIL;
        }

        return cortex_a8_init_debug_access(target);
}

static const struct command_registration cortex_a8_exec_command_handlers[] = {
        {
                .name = "cache_info",
                .handler = cortex_a8_handle_cache_info_command,
                .mode = COMMAND_EXEC,
                .help = "display information about target caches",
        },
        {
                .name = "dbginit",
                .handler = cortex_a8_handle_dbginit_command,
                .mode = COMMAND_EXEC,
                .help = "Initialize core debug",
        },
        COMMAND_REGISTRATION_DONE
};
static const struct command_registration cortex_a8_command_handlers[] = {
        {
                .chain = arm_command_handlers,
        },
        {
                .chain = armv7a_command_handlers,
        },
        {
                .name = "cortex_a8",
                .mode = COMMAND_ANY,
                .help = "Cortex-A8 command group",
                .chain = cortex_a8_exec_command_handlers,
        },
        COMMAND_REGISTRATION_DONE
};

struct target_type cortexa8_target = {
        .name = "cortex_a8",

        .poll = cortex_a8_poll,
        .arch_state = armv7a_arch_state,

        .target_request_data = NULL,

        .halt = cortex_a8_halt,
        .resume = cortex_a8_resume,
        .step = cortex_a8_step,

        .assert_reset = cortex_a8_assert_reset,
        .deassert_reset = cortex_a8_deassert_reset,
        .soft_reset_halt = NULL,

        /* REVISIT allow exporting VFP3 registers ... */
        .get_gdb_reg_list = arm_get_gdb_reg_list,

        .read_memory = cortex_a8_read_memory,
        .write_memory = cortex_a8_write_memory,
        .bulk_write_memory = cortex_a8_bulk_write_memory,

        .checksum_memory = arm_checksum_memory,
        .blank_check_memory = arm_blank_check_memory,

        .run_algorithm = armv4_5_run_algorithm,

        .add_breakpoint = cortex_a8_add_breakpoint,
        .remove_breakpoint = cortex_a8_remove_breakpoint,
        .add_watchpoint = NULL,
        .remove_watchpoint = NULL,

        .commands = cortex_a8_command_handlers,
        .target_create = cortex_a8_target_create,
        .init_target = cortex_a8_init_target,
        .examine = cortex_a8_examine,

        .read_phys_memory = cortex_a8_read_phys_memory,
        .write_phys_memory = cortex_a8_write_phys_memory,
        .mmu = cortex_a8_mmu,
        .virt2phys = cortex_a8_virt2phys,

};