stm8.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/*
*   OpenOCD STM8 target driver
*   Copyright (C) 2017  Ake Rehnman
*   ake.rehnman(at)gmail.com
*/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <helper/log.h>
#include "target.h"
#include "target_type.h"
#include "hello.h"
#include "jtag/interface.h"
#include "jtag/jtag.h"
#include "jtag/swim.h"
#include "register.h"
#include "breakpoints.h"
#include "algorithm.h"
#include "stm8.h"
 
static struct reg_cache *stm8_build_reg_cache(struct target *target);
static int stm8_read_core_reg(struct target *target, unsigned int num);
static int stm8_write_core_reg(struct target *target, unsigned int num);
static int stm8_save_context(struct target *target);
static void stm8_enable_breakpoints(struct target *target);
static int stm8_unset_breakpoint(struct target *target,
        struct breakpoint *breakpoint);
static int stm8_set_breakpoint(struct target *target,
        struct breakpoint *breakpoint);
static void stm8_enable_watchpoints(struct target *target);
static int stm8_unset_watchpoint(struct target *target,
        struct watchpoint *watchpoint);
static int (*adapter_speed)(int speed);
extern struct adapter_driver *adapter_driver;
 
static const struct {
    unsigned int id;
    const char *name;
    const uint8_t bits;
    enum reg_type type;
    const char *group;
    const char *feature;
    int flag;
} stm8_regs[] = {
    {  0,  "pc", 32, REG_TYPE_UINT32, "general", "org.gnu.gdb.stm8.core", 0 },
    {  1,  "a", 8, REG_TYPE_UINT8, "general", "org.gnu.gdb.stm8.core", 0 },
    {  2,  "x", 16, REG_TYPE_UINT16, "general", "org.gnu.gdb.stm8.core", 0 },
    {  3,  "y", 16, REG_TYPE_UINT16, "general", "org.gnu.gdb.stm8.core", 0 },
    {  4,  "sp", 16, REG_TYPE_UINT16, "general", "org.gnu.gdb.stm8.core", 0 },
    {  5,  "cc", 8, REG_TYPE_UINT8, "general", "org.gnu.gdb.stm8.core", 0 },
};
 
#define STM8_NUM_REGS ARRAY_SIZE(stm8_regs)
#define STM8_PC 0
#define STM8_A 1
#define STM8_X 2
#define STM8_Y 3
#define STM8_SP 4
#define STM8_CC 5
 
#define CC_I0 0x8
#define CC_I1 0x20
 
#define DM_REGS 0x7f00
#define DM_REG_A 0x7f00
#define DM_REG_PC 0x7f01
#define DM_REG_X 0x7f04
#define DM_REG_Y 0x7f06
#define DM_REG_SP 0x7f08
#define DM_REG_CC 0x7f0a
 
#define DM_BKR1E 0x7f90
#define DM_BKR2E 0x7f93
#define DM_CR1 0x7f96
#define DM_CR2 0x7f97
#define DM_CSR1 0x7f98
#define DM_CSR2 0x7f99
 
#define STE 0x40
#define STF 0x20
#define RST 0x10
#define BRW 0x08
#define BK2F 0x04
#define BK1F 0x02
 
#define SWBRK 0x20
#define SWBKF 0x10
#define STALL 0x08
#define FLUSH 0x01
 
#define FLASH_CR1_STM8S 0x505A
#define FLASH_CR2_STM8S 0x505B
#define FLASH_NCR2_STM8S 0x505C
#define FLASH_IAPSR_STM8S 0x505F
#define FLASH_PUKR_STM8S 0x5062
#define FLASH_DUKR_STM8S 0x5064
 
#define FLASH_CR1_STM8L 0x5050
#define FLASH_CR2_STM8L 0x5051
#define FLASH_NCR2_STM8L 0
#define FLASH_PUKR_STM8L 0x5052
#define FLASH_DUKR_STM8L 0x5053
#define FLASH_IAPSR_STM8L 0x5054
 
/* FLASH_IAPSR */
#define HVOFF 0x40
#define DUL 0x08
#define EOP 0x04
#define PUL 0x02
#define WR_PG_DIS 0x01
 
/* FLASH_CR2 */
#define OPT 0x80
#define WPRG 0x40
#define ERASE 0x20
#define FPRG 0x10
#define PRG 0x01
 
/* SWIM_CSR */
#define SAFE_MASK 0x80
#define NO_ACCESS 0x40
#define SWIM_DM 0x20
#define HS 0x10
#define OSCOFF 0x08
#define SWIM_RST 0x04
#define HSIT 0x02
#define PRI 0x01
 
#define SWIM_CSR 0x7f80
 
#define STM8_BREAK 0x8B
 
enum mem_type {
    RAM,
    FLASH,
    EEPROM,
    OPTION
};
 
struct stm8_algorithm {
    int common_magic;
};
 
struct stm8_core_reg {
    uint32_t num;
    struct target *target;
};
 
enum hw_break_type {
    /* break on execute */
    HWBRK_EXEC,
    /* break on read */
    HWBRK_RD,
    /* break on write */
    HWBRK_WR,
    /* break on read, write and execute */
    HWBRK_ACC
};
 
struct stm8_comparator {
    bool used;
    uint32_t bp_value;
    uint32_t reg_address;
    enum hw_break_type type;
};
 
static int stm8_adapter_read_memory(struct target *target,
        uint32_t addr, int size, int count, void *buf)
{
    return swim_read_mem(addr, size, count, buf);
}
 
static int stm8_adapter_write_memory(struct target *target,
        uint32_t addr, int size, int count, const void *buf)
{
    return swim_write_mem(addr, size, count, buf);
}
 
static int stm8_write_u8(struct target *target,
        uint32_t addr, uint8_t val)
{
    uint8_t buf[1];
 
    buf[0] = val;
    return swim_write_mem(addr, 1, 1, buf);
}
 
static int stm8_read_u8(struct target *target,
        uint32_t addr, uint8_t *val)
{
    return swim_read_mem(addr, 1, 1, val);
}
 
/*
    <enable == 0> Disables interrupts.
    If interrupts are enabled they are masked and the cc register
    is saved.
 
    <enable == 1> Enables interrupts.
    Enable interrupts is actually restoring I1 I0 state from previous
    call with enable == 0. Note that if stepping and breaking on a sim
    instruction will NOT work since the interrupt flags are restored on
    debug_entry. We don't have any way for the debugger to exclusively
    disable the interrupts
*/
static int stm8_enable_interrupts(struct target *target, int enable)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    uint8_t cc;
 
    if (enable) {
        if (!stm8->cc_valid)
            return ERROR_OK; /* cc was not stashed */
        /* fetch current cc */
        stm8_read_u8(target, DM_REG_CC, &cc);
        /* clear I1 I0 */
        cc &= ~(CC_I0 + CC_I1);
        /* restore I1 & I0 from stash*/
        cc |= (stm8->cc & (CC_I0+CC_I1));
        /* update current cc */
        stm8_write_u8(target, DM_REG_CC, cc);
        stm8->cc_valid = false;
    } else {
        stm8_read_u8(target, DM_REG_CC, &cc);
        if ((cc & CC_I0) && (cc & CC_I1))
            return ERROR_OK; /* interrupts already masked */
        /* stash cc */
        stm8->cc = cc;
        stm8->cc_valid = true;
        /* mask interrupts (disable) */
        cc |= (CC_I0 + CC_I1);
        stm8_write_u8(target, DM_REG_CC, cc);
    }
 
    return ERROR_OK;
}
 
static int stm8_set_hwbreak(struct target *target,
        struct stm8_comparator comparator_list[])
{
    uint8_t buf[3];
    int i, ret;
 
    /* Refer to Table 4 in UM0470 */
    uint8_t bc = 0x5;
    uint8_t bir = 0;
    uint8_t biw = 0;
 
    uint32_t data;
    uint32_t addr;
 
    if (!comparator_list[0].used) {
        comparator_list[0].type = HWBRK_EXEC;
        comparator_list[0].bp_value = -1;
    }
 
    if (!comparator_list[1].used) {
        comparator_list[1].type = HWBRK_EXEC;
        comparator_list[1].bp_value = -1;
    }
 
    if ((comparator_list[0].type == HWBRK_EXEC)
            && (comparator_list[1].type == HWBRK_EXEC)) {
        comparator_list[0].reg_address = 0;
        comparator_list[1].reg_address = 1;
    }
 
    if ((comparator_list[0].type == HWBRK_EXEC)
            && (comparator_list[1].type != HWBRK_EXEC)) {
        comparator_list[0].reg_address = 0;
        comparator_list[1].reg_address = 1;
        switch (comparator_list[1].type) {
        case HWBRK_RD:
            bir = 1;
            break;
        case HWBRK_WR:
            biw = 1;
            break;
        default:
            bir = 1;
            biw = 1;
            break;
        }
    }
 
    if ((comparator_list[1].type == HWBRK_EXEC)
            && (comparator_list[0].type != HWBRK_EXEC)) {
        comparator_list[0].reg_address = 1;
        comparator_list[1].reg_address = 0;
        switch (comparator_list[0].type) {
        case HWBRK_RD:
            bir = 1;
            break;
        case HWBRK_WR:
            biw = 1;
            break;
        default:
            bir = 1;
            biw = 1;
            break;
        }
    }
 
    if ((comparator_list[0].type != HWBRK_EXEC)
            && (comparator_list[1].type != HWBRK_EXEC)) {
        if (comparator_list[0].type != comparator_list[1].type) {
            LOG_ERROR("data hw breakpoints must be of same type");
            return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
    }
 
    for (i = 0; i < 2; i++) {
        data = comparator_list[i].bp_value;
        addr = comparator_list[i].reg_address;
 
        buf[0] = data >> 16;
        buf[1] = data >> 8;
        buf[2] = data;
 
        if (addr == 0) {
            ret = stm8_adapter_write_memory(target, DM_BKR1E, 1, 3, buf);
            LOG_DEBUG("DM_BKR1E=%" PRIx32, data);
        } else if (addr == 1) {
            ret = stm8_adapter_write_memory(target, DM_BKR2E, 1, 3, buf);
            LOG_DEBUG("DM_BKR2E=%" PRIx32, data);
        } else {
            LOG_DEBUG("addr=%" PRIu32, addr);
            return ERROR_FAIL;
        }
 
        if (ret != ERROR_OK)
            return ret;
 
        ret = stm8_write_u8(target, DM_CR1,
            (bc << 3) + (bir << 2) + (biw << 1));
        LOG_DEBUG("DM_CR1=%" PRIx8, buf[0]);
        if (ret != ERROR_OK)
            return ret;
 
    }
    return ERROR_OK;
}
 
/* read DM control and status regs */
static int stm8_read_dm_csrx(struct target *target, uint8_t *csr1,
        uint8_t *csr2)
{
    int ret;
    uint8_t buf[2];
 
    ret =  stm8_adapter_read_memory(target, DM_CSR1, 1, sizeof(buf), buf);
    if (ret != ERROR_OK)
        return ret;
    if (csr1)
        *csr1 = buf[0];
    if (csr2)
        *csr2 = buf[1];
    return ERROR_OK;
}
 
/* set or clear the single step flag in DM */
static int stm8_config_step(struct target *target, int enable)
{
    int ret;
    uint8_t csr1, csr2;
 
    ret = stm8_read_dm_csrx(target, &csr1, &csr2);
    if (ret != ERROR_OK)
        return ret;
    if (enable)
        csr1 |= STE;
    else
        csr1 &= ~STE;
 
    ret =  stm8_write_u8(target, DM_CSR1, csr1);
    if (ret != ERROR_OK)
        return ret;
    return ERROR_OK;
}
 
/* set the stall flag in DM */
static int stm8_debug_stall(struct target *target)
{
    int ret;
    uint8_t csr1, csr2;
 
    ret = stm8_read_dm_csrx(target, &csr1, &csr2);
    if (ret != ERROR_OK)
        return ret;
    csr2 |= STALL;
    ret =  stm8_write_u8(target, DM_CSR2, csr2);
    if (ret != ERROR_OK)
        return ret;
    return ERROR_OK;
}
 
static int stm8_configure_break_unit(struct target *target)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (stm8->bp_scanned)
        return ERROR_OK;
 
    stm8->num_hw_bpoints = 2;
    stm8->num_hw_bpoints_avail = stm8->num_hw_bpoints;
 
    stm8->hw_break_list = calloc(stm8->num_hw_bpoints,
        sizeof(struct stm8_comparator));
 
    stm8->hw_break_list[0].reg_address = 0;
    stm8->hw_break_list[1].reg_address = 1;
 
    LOG_DEBUG("hw breakpoints: numinst %i numdata %i", stm8->num_hw_bpoints,
        stm8->num_hw_bpoints);
 
    stm8->bp_scanned = true;
 
    return ERROR_OK;
}
 
static int stm8_examine_debug_reason(struct target *target)
{
    int retval;
    uint8_t csr1, csr2;
 
    retval = stm8_read_dm_csrx(target, &csr1, &csr2);
    if (retval == ERROR_OK)
        LOG_DEBUG("csr1 = 0x%02X csr2 = 0x%02X", csr1, csr2);
 
    if ((target->debug_reason != DBG_REASON_DBGRQ)
        && (target->debug_reason != DBG_REASON_SINGLESTEP)) {
 
        if (retval != ERROR_OK)
            return retval;
 
        if (csr1 & RST)
            /* halted on reset */
            target->debug_reason = DBG_REASON_UNDEFINED;
 
        if (csr1 & (BK1F+BK2F))
            /* we have halted on a  breakpoint (or wp)*/
            target->debug_reason = DBG_REASON_BREAKPOINT;
 
        if (csr2 & SWBKF)
            /* we have halted on a  breakpoint */
            target->debug_reason = DBG_REASON_BREAKPOINT;
 
    }
 
    return ERROR_OK;
}
 
static int stm8_debug_entry(struct target *target)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    /* restore interrupts */
    stm8_enable_interrupts(target, 1);
 
    stm8_save_context(target);
 
    /* make sure stepping disabled STE bit in CSR1 cleared */
    stm8_config_step(target, 0);
 
    /* attempt to find halt reason */
    stm8_examine_debug_reason(target);
 
    LOG_DEBUG("entered debug state at PC 0x%" PRIx32 ", target->state: %s",
        buf_get_u32(stm8->core_cache->reg_list[STM8_PC].value, 0, 32),
        target_state_name(target));
 
    return ERROR_OK;
}
 
/* clear stall flag in DM and flush instruction pipe */
static int stm8_exit_debug(struct target *target)
{
    int ret;
    uint8_t csr1, csr2;
 
    ret = stm8_read_dm_csrx(target, &csr1, &csr2);
    if (ret != ERROR_OK)
        return ret;
    csr2 |= FLUSH;
    ret =  stm8_write_u8(target, DM_CSR2, csr2);
    if (ret != ERROR_OK)
        return ret;
 
    csr2 &= ~STALL;
    csr2 |= SWBRK;
    ret =  stm8_write_u8(target, DM_CSR2, csr2);
    if (ret != ERROR_OK)
        return ret;
    return ERROR_OK;
}
 
static int stm8_read_regs(struct target *target, uint32_t regs[])
{
    int ret;
    uint8_t buf[11];
 
    ret =  stm8_adapter_read_memory(target, DM_REGS, 1, sizeof(buf), buf);
    if (ret != ERROR_OK)
        return ret;
 
    regs[0] = be_to_h_u24(buf+DM_REG_PC-DM_REGS);
    regs[1] = buf[DM_REG_A-DM_REGS];
    regs[2] = be_to_h_u16(buf+DM_REG_X-DM_REGS);
    regs[3] = be_to_h_u16(buf+DM_REG_Y-DM_REGS);
    regs[4] = be_to_h_u16(buf+DM_REG_SP-DM_REGS);
    regs[5] = buf[DM_REG_CC-DM_REGS];
 
    return ERROR_OK;
}
 
static int stm8_write_regs(struct target *target, uint32_t regs[])
{
    int ret;
    uint8_t buf[11];
 
    h_u24_to_be(buf+DM_REG_PC-DM_REGS, regs[0]);
    buf[DM_REG_A-DM_REGS] = regs[1];
    h_u16_to_be(buf+DM_REG_X-DM_REGS, regs[2]);
    h_u16_to_be(buf+DM_REG_Y-DM_REGS, regs[3]);
    h_u16_to_be(buf+DM_REG_SP-DM_REGS, regs[4]);
    buf[DM_REG_CC-DM_REGS] = regs[5];
 
    ret =  stm8_adapter_write_memory(target, DM_REGS, 1, sizeof(buf), buf);
    if (ret != ERROR_OK)
        return ret;
 
    return ERROR_OK;
}
 
static int stm8_get_core_reg(struct reg *reg)
{
    int retval;
    struct stm8_core_reg *stm8_reg = reg->arch_info;
    struct target *target = stm8_reg->target;
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (target->state != TARGET_HALTED)
        return ERROR_TARGET_NOT_HALTED;
 
    retval = stm8->read_core_reg(target, stm8_reg->num);
 
    return retval;
}
 
static int stm8_set_core_reg(struct reg *reg, uint8_t *buf)
{
    struct stm8_core_reg *stm8_reg = reg->arch_info;
    struct target *target = stm8_reg->target;
    uint32_t value = buf_get_u32(buf, 0, reg->size);
 
    if (target->state != TARGET_HALTED)
        return ERROR_TARGET_NOT_HALTED;
 
    buf_set_u32(reg->value, 0, 32, value);
    reg->dirty = true;
    reg->valid = true;
 
    return ERROR_OK;
}
 
static int stm8_save_context(struct target *target)
{
    unsigned int i;
 
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    /* read core registers */
    stm8_read_regs(target, stm8->core_regs);
 
    for (i = 0; i < STM8_NUM_REGS; i++) {
        if (!stm8->core_cache->reg_list[i].valid)
            stm8->read_core_reg(target, i);
    }
 
    return ERROR_OK;
}
 
static int stm8_restore_context(struct target *target)
{
    unsigned int i;
 
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    for (i = 0; i < STM8_NUM_REGS; i++) {
        if (stm8->core_cache->reg_list[i].dirty)
            stm8->write_core_reg(target, i);
    }
 
    /* write core regs */
    stm8_write_regs(target, stm8->core_regs);
 
    return ERROR_OK;
}
 
static int stm8_unlock_flash(struct target *target)
{
    uint8_t data[1];
 
    struct stm8_common *stm8 = target_to_stm8(target);
 
    /* check if flash is unlocked */
    stm8_read_u8(target, stm8->flash_iapsr, data);
    if (~data[0] & PUL) {
        /* unlock flash */
        stm8_write_u8(target, stm8->flash_pukr, 0x56);
        stm8_write_u8(target, stm8->flash_pukr, 0xae);
    }
 
    stm8_read_u8(target, stm8->flash_iapsr, data);
    if (~data[0] & PUL)
        return ERROR_FAIL;
    return ERROR_OK;
}
 
static int stm8_unlock_eeprom(struct target *target)
{
    uint8_t data[1];
 
    struct stm8_common *stm8 = target_to_stm8(target);
 
    /* check if eeprom is unlocked */
    stm8_read_u8(target, stm8->flash_iapsr, data);
    if (~data[0] & DUL) {
        /* unlock eeprom */
        stm8_write_u8(target, stm8->flash_dukr, 0xae);
        stm8_write_u8(target, stm8->flash_dukr, 0x56);
    }
 
    stm8_read_u8(target, stm8->flash_iapsr, data);
    if (~data[0] & DUL)
        return ERROR_FAIL;
    return ERROR_OK;
}
 
static int stm8_write_flash(struct target *target, enum mem_type type,
        uint32_t address,
        uint32_t size, uint32_t count, uint32_t blocksize_param,
        const uint8_t *buffer)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    uint8_t iapsr;
    uint8_t opt = 0;
    unsigned int i;
    uint32_t blocksize = 0;
    uint32_t bytecnt;
    int res;
 
    switch (type) {
        case (FLASH):
            stm8_unlock_flash(target);
            break;
        case (EEPROM):
            stm8_unlock_eeprom(target);
            break;
        case (OPTION):
            stm8_unlock_eeprom(target);
            opt = OPT;
            break;
        default:
            LOG_ERROR("BUG: wrong mem_type %d", type);
            assert(0);
    }
 
    if (size == 2) {
        /* we don't support short writes */
        count = count * 2;
        size = 1;
    }
 
    bytecnt = count * size;
 
    while (bytecnt) {
        if ((bytecnt >= blocksize_param) && ((address & (blocksize_param-1)) == 0)) {
            if (stm8->flash_cr2)
                stm8_write_u8(target, stm8->flash_cr2, PRG + opt);
            if (stm8->flash_ncr2)
                stm8_write_u8(target, stm8->flash_ncr2, ~(PRG + opt));
            blocksize = blocksize_param;
        } else
        if ((bytecnt >= 4) && ((address & 0x3) == 0)) {
            if (stm8->flash_cr2)
                stm8_write_u8(target, stm8->flash_cr2, WPRG + opt);
            if (stm8->flash_ncr2)
                stm8_write_u8(target, stm8->flash_ncr2, ~(WPRG + opt));
            blocksize = 4;
        } else
        if (blocksize != 1) {
            if (stm8->flash_cr2)
                stm8_write_u8(target, stm8->flash_cr2, opt);
            if (stm8->flash_ncr2)
                stm8_write_u8(target, stm8->flash_ncr2, ~opt);
            blocksize = 1;
        }
 
        res = stm8_adapter_write_memory(target, address, 1, blocksize, buffer);
        if (res != ERROR_OK)
            return res;
        address += blocksize;
        buffer += blocksize;
        bytecnt -= blocksize;
 
        /* lets hang here until end of program (EOP) */
        for (i = 0; i < 16; i++) {
            stm8_read_u8(target, stm8->flash_iapsr, &iapsr);
            if (iapsr & EOP)
                break;
            else
                usleep(1000);
        }
        if (i == 16)
            return ERROR_FAIL;
    }
 
    /* disable write access */
    res = stm8_write_u8(target, stm8->flash_iapsr, 0x0);
 
    if (res != ERROR_OK)
        return ERROR_FAIL;
 
    return ERROR_OK;
}
 
static int stm8_write_memory(struct target *target, target_addr_t address,
        uint32_t size, uint32_t count,
        const uint8_t *buffer)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    LOG_DEBUG("address: 0x%8.8" TARGET_PRIxADDR
        ", size: 0x%8.8" PRIx32
        ", count: 0x%8.8" PRIx32,
        address, size, count);
 
    if (target->state != TARGET_HALTED)
        LOG_WARNING("target not halted");
 
    int retval;
 
    if ((address >= stm8->flashstart) && (address <= stm8->flashend))
        retval = stm8_write_flash(target, FLASH, address, size, count,
                stm8->blocksize, buffer);
    else if ((address >= stm8->eepromstart) && (address <= stm8->eepromend))
        retval = stm8_write_flash(target, EEPROM, address, size, count,
                stm8->blocksize, buffer);
    else if ((address >= stm8->optionstart) && (address <= stm8->optionend))
        retval = stm8_write_flash(target, OPTION, address, size, count, 0, buffer);
    else
        retval = stm8_adapter_write_memory(target, address, size, count,
                buffer);
 
    if (retval != ERROR_OK)
        return ERROR_TARGET_FAILURE;
 
    return retval;
}
 
static int stm8_read_memory(struct target *target, target_addr_t address,
        uint32_t size, uint32_t count, uint8_t *buffer)
{
    LOG_DEBUG("address: 0x%8.8" TARGET_PRIxADDR
        ", size: 0x%8.8" PRIx32
        ", count: 0x%8.8" PRIx32,
        address, size, count);
 
    if (target->state != TARGET_HALTED)
        LOG_WARNING("target not halted");
 
    int retval;
    retval = stm8_adapter_read_memory(target, address, size, count, buffer);
 
    if (retval != ERROR_OK)
        return ERROR_TARGET_FAILURE;
 
    return retval;
}
 
static int stm8_speed(int speed)
{
    int retval;
    uint8_t csr;
 
    LOG_DEBUG("stm8_speed: %d", speed);
 
    csr = SAFE_MASK | SWIM_DM;
    if (speed >= SWIM_FREQ_HIGH)
        csr |= HS;
 
    LOG_DEBUG("writing B0 to SWIM_CSR (SAFE_MASK + SWIM_DM + HS:%d)", csr & HS ? 1 : 0);
    retval = stm8_write_u8(NULL, SWIM_CSR, csr);
    if (retval != ERROR_OK)
        return retval;
    return adapter_speed(speed);
}
 
static int stm8_init(struct command_context *cmd_ctx, struct target *target)
{
    /*
     * FIXME: this is a temporarily hack that needs better implementation.
     * Being the only overwrite of adapter_driver, it prevents declaring const
     * the struct adapter_driver.
     * intercept adapter_driver->speed() calls
     */
    adapter_speed = adapter_driver->speed;
    adapter_driver->speed = stm8_speed;
 
    stm8_build_reg_cache(target);
 
    return ERROR_OK;
}
 
static int stm8_poll(struct target *target)
{
    int retval = ERROR_OK;
    uint8_t csr1, csr2;
 
#ifdef LOG_STM8
    LOG_DEBUG("target->state=%d", target->state);
#endif
 
    /* read dm_csrx control regs */
    retval = stm8_read_dm_csrx(target, &csr1, &csr2);
    if (retval != ERROR_OK) {
        LOG_DEBUG("stm8_read_dm_csrx failed retval=%d", retval);
        /*
           We return ERROR_OK here even if we didn't get an answer.
           openocd will call target_wait_state until we get target state TARGET_HALTED
        */
        return ERROR_OK;
    }
 
    /* check for processor halted */
    if (csr2 & STALL) {
        if (target->state != TARGET_HALTED) {
            if (target->state == TARGET_UNKNOWN)
                LOG_DEBUG("DM_CSR2_STALL already set during server startup.");
 
            retval = stm8_debug_entry(target);
            if (retval != ERROR_OK) {
                LOG_DEBUG("stm8_debug_entry failed retval=%d", retval);
                return ERROR_TARGET_FAILURE;
            }
 
            if (target->state == TARGET_DEBUG_RUNNING) {
                target->state = TARGET_HALTED;
                target_call_event_callbacks(target, TARGET_EVENT_DEBUG_HALTED);
            } else {
                target->state = TARGET_HALTED;
                target_call_event_callbacks(target, TARGET_EVENT_HALTED);
            }
        }
    } else
        target->state = TARGET_RUNNING;
#ifdef LOG_STM8
    LOG_DEBUG("csr1 = 0x%02X csr2 = 0x%02X", csr1, csr2);
#endif
    return ERROR_OK;
}
 
static int stm8_halt(struct target *target)
{
    LOG_DEBUG("target->state: %s", target_state_name(target));
 
    if (target->state == TARGET_HALTED) {
        LOG_DEBUG("target was already halted");
        return ERROR_OK;
    }
 
    if (target->state == TARGET_UNKNOWN)
        LOG_WARNING("target was in unknown state when halt was requested");
 
    if (target->state == TARGET_RESET) {
        /* we came here in a reset_halt or reset_init sequence
         * debug entry was already prepared in stm8_assert_reset()
         */
        target->debug_reason = DBG_REASON_DBGRQ;
 
        return ERROR_OK;
    }
 
 
    /* break processor */
    stm8_debug_stall(target);
 
    target->debug_reason = DBG_REASON_DBGRQ;
 
    return ERROR_OK;
}
 
static int stm8_reset_assert(struct target *target)
{
    int res = ERROR_OK;
    struct stm8_common *stm8 = target_to_stm8(target);
    bool use_srst_fallback = true;
 
    enum reset_types jtag_reset_config = jtag_get_reset_config();
 
    if (jtag_reset_config & RESET_HAS_SRST) {
        res = adapter_assert_reset();
        if (res == ERROR_OK)
            /* hardware srst supported */
            use_srst_fallback = false;
        else if (res != ERROR_COMMAND_NOTFOUND)
            /* some other failure */
            return res;
    }
 
    if (use_srst_fallback) {
        LOG_DEBUG("Hardware srst not supported, falling back to swim reset");
        res = swim_system_reset();
        if (res != ERROR_OK)
            return res;
    }
 
    /* registers are now invalid */
    register_cache_invalidate(stm8->core_cache);
 
    target->state = TARGET_RESET;
    target->debug_reason = DBG_REASON_NOTHALTED;
 
    if (target->reset_halt) {
        res = target_halt(target);
        if (res != ERROR_OK)
            return res;
    }
 
    return ERROR_OK;
}
 
static int stm8_reset_deassert(struct target *target)
{
    int res;
    enum reset_types jtag_reset_config = jtag_get_reset_config();
 
    if (jtag_reset_config & RESET_HAS_SRST) {
        res = adapter_deassert_reset();
        if ((res != ERROR_OK) && (res != ERROR_COMMAND_NOTFOUND))
            return res;
    }
 
    /* The cpu should now be stalled. If halt was requested
       let poll detect the stall */
    if (target->reset_halt)
        return ERROR_OK;
 
    /* Instead of going through saving context, polling and
       then resuming target again just clear stall and proceed. */
    target->state = TARGET_RUNNING;
    return stm8_exit_debug(target);
}
 
/* stm8_single_step_core() is only used for stepping over breakpoints
   from stm8_resume() */
static int stm8_single_step_core(struct target *target)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    /* configure single step mode */
    stm8_config_step(target, 1);
 
    /* disable interrupts while stepping */
    if (!stm8->enable_step_irq)
        stm8_enable_interrupts(target, 0);
 
    /* exit debug mode */
    stm8_exit_debug(target);
 
    stm8_debug_entry(target);
 
    return ERROR_OK;
}
 
static int stm8_resume(struct target *target, int current,
        target_addr_t address, int handle_breakpoints,
        int debug_execution)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    struct breakpoint *breakpoint = NULL;
    uint32_t resume_pc;
 
    LOG_DEBUG("%d " TARGET_ADDR_FMT " %d %d", current, address,
            handle_breakpoints, debug_execution);
 
    if (target->state != TARGET_HALTED) {
        LOG_TARGET_ERROR(target, "not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (!debug_execution) {
        target_free_all_working_areas(target);
        stm8_enable_breakpoints(target);
        stm8_enable_watchpoints(target);
        struct stm8_comparator *comparator_list = stm8->hw_break_list;
        stm8_set_hwbreak(target, comparator_list);
    }
 
    /* current = 1: continue on current pc,
       otherwise continue at <address> */
    if (!current) {
        buf_set_u32(stm8->core_cache->reg_list[STM8_PC].value,
            0, 32, address);
        stm8->core_cache->reg_list[STM8_PC].dirty = true;
        stm8->core_cache->reg_list[STM8_PC].valid = true;
    }
 
    if (!current)
        resume_pc = address;
    else
        resume_pc = buf_get_u32(
            stm8->core_cache->reg_list[STM8_PC].value,
            0, 32);
 
    stm8_restore_context(target);
 
    /* the front-end may request us not to handle breakpoints */
    if (handle_breakpoints) {
        /* Single step past breakpoint at current address */
        breakpoint = breakpoint_find(target, resume_pc);
        if (breakpoint) {
            LOG_DEBUG("unset breakpoint at " TARGET_ADDR_FMT,
                    breakpoint->address);
            stm8_unset_breakpoint(target, breakpoint);
            stm8_single_step_core(target);
            stm8_set_breakpoint(target, breakpoint);
        }
    }
 
    /* disable interrupts if we are debugging */
    if (debug_execution)
        stm8_enable_interrupts(target, 0);
 
    /* exit debug mode */
    stm8_exit_debug(target);
    target->debug_reason = DBG_REASON_NOTHALTED;
 
    /* registers are now invalid */
    register_cache_invalidate(stm8->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);
    }
 
    return ERROR_OK;
}
 
static int stm8_init_flash_regs(bool enable_stm8l, struct stm8_common *stm8)
{
    stm8->enable_stm8l = enable_stm8l;
 
    if (stm8->enable_stm8l) {
        stm8->flash_cr2 = FLASH_CR2_STM8L;
        stm8->flash_ncr2 = FLASH_NCR2_STM8L;
        stm8->flash_iapsr = FLASH_IAPSR_STM8L;
        stm8->flash_dukr = FLASH_DUKR_STM8L;
        stm8->flash_pukr = FLASH_PUKR_STM8L;
    } else {
        stm8->flash_cr2 = FLASH_CR2_STM8S;
        stm8->flash_ncr2 = FLASH_NCR2_STM8S;
        stm8->flash_iapsr = FLASH_IAPSR_STM8S;
        stm8->flash_dukr = FLASH_DUKR_STM8S;
        stm8->flash_pukr = FLASH_PUKR_STM8S;
    }
    return ERROR_OK;
}
 
static int stm8_init_arch_info(struct target *target,
        struct stm8_common *stm8, struct jtag_tap *tap)
{
    target->endianness = TARGET_BIG_ENDIAN;
    target->arch_info = stm8;
    stm8->common_magic = STM8_COMMON_MAGIC;
    stm8->fast_data_area = NULL;
    stm8->blocksize = 0x80;
    stm8->flashstart = 0x8000;
    stm8->flashend = 0xffff;
    stm8->eepromstart = 0x4000;
    stm8->eepromend = 0x43ff;
    stm8->optionstart = 0x4800;
    stm8->optionend = 0x487F;
 
    /* has breakpoint/watchpoint unit been scanned */
    stm8->bp_scanned = false;
    stm8->hw_break_list = NULL;
 
    stm8->read_core_reg = stm8_read_core_reg;
    stm8->write_core_reg = stm8_write_core_reg;
 
    stm8_init_flash_regs(0, stm8);
 
    return ERROR_OK;
}
 
static int stm8_target_create(struct target *target,
        Jim_Interp *interp)
{
 
    struct stm8_common *stm8 = calloc(1, sizeof(struct stm8_common));
 
    stm8_init_arch_info(target, stm8, target->tap);
    stm8_configure_break_unit(target);
 
    return ERROR_OK;
}
 
static int stm8_read_core_reg(struct target *target, unsigned int num)
{
    uint32_t reg_value;
 
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (num >= STM8_NUM_REGS)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    reg_value = stm8->core_regs[num];
    LOG_DEBUG("read core reg %i value 0x%" PRIx32 "", num, reg_value);
    buf_set_u32(stm8->core_cache->reg_list[num].value, 0, 32, reg_value);
    stm8->core_cache->reg_list[num].valid = true;
    stm8->core_cache->reg_list[num].dirty = false;
 
    return ERROR_OK;
}
 
static int stm8_write_core_reg(struct target *target, unsigned int num)
{
    uint32_t reg_value;
 
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (num >= STM8_NUM_REGS)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    reg_value = buf_get_u32(stm8->core_cache->reg_list[num].value, 0, 32);
    stm8->core_regs[num] = reg_value;
    LOG_DEBUG("write core reg %i value 0x%" PRIx32 "", num, reg_value);
    stm8->core_cache->reg_list[num].valid = true;
    stm8->core_cache->reg_list[num].dirty = false;
 
    return ERROR_OK;
}
 
static const char *stm8_get_gdb_arch(const struct target *target)
{
    return "stm8";
}
 
static int stm8_get_gdb_reg_list(struct target *target, struct reg **reg_list[],
        int *reg_list_size, enum target_register_class reg_class)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
    unsigned int i;
 
    *reg_list_size = STM8_NUM_REGS;
    *reg_list = malloc(sizeof(struct reg *) * (*reg_list_size));
 
    for (i = 0; i < STM8_NUM_REGS; i++)
        (*reg_list)[i] = &stm8->core_cache->reg_list[i];
 
    return ERROR_OK;
}
 
static const struct reg_arch_type stm8_reg_type = {
    .get = stm8_get_core_reg,
    .set = stm8_set_core_reg,
};
 
static struct reg_cache *stm8_build_reg_cache(struct target *target)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    int num_regs = STM8_NUM_REGS;
    struct reg_cache **cache_p = register_get_last_cache_p(&target->reg_cache);
    struct reg_cache *cache = malloc(sizeof(struct reg_cache));
    struct reg *reg_list = calloc(num_regs, sizeof(struct reg));
    struct stm8_core_reg *arch_info = malloc(
            sizeof(struct stm8_core_reg) * num_regs);
    struct reg_feature *feature;
    int i;
 
    /* Build the process context cache */
    cache->name = "stm8 registers";
    cache->next = NULL;
    cache->reg_list = reg_list;
    cache->num_regs = num_regs;
    (*cache_p) = cache;
    stm8->core_cache = cache;
 
    for (i = 0; i < num_regs; i++) {
        arch_info[i].num = stm8_regs[i].id;
        arch_info[i].target = target;
 
        reg_list[i].name = stm8_regs[i].name;
        reg_list[i].size = stm8_regs[i].bits;
 
        reg_list[i].value = calloc(1, 4);
        reg_list[i].valid = false;
        reg_list[i].type = &stm8_reg_type;
        reg_list[i].arch_info = &arch_info[i];
 
        reg_list[i].reg_data_type = calloc(1, sizeof(struct reg_data_type));
        if (reg_list[i].reg_data_type)
            reg_list[i].reg_data_type->type = stm8_regs[i].type;
        else {
            LOG_ERROR("unable to allocate reg type list");
            return NULL;
        }
 
        reg_list[i].dirty = false;
        reg_list[i].group = stm8_regs[i].group;
        reg_list[i].number = stm8_regs[i].id;
        reg_list[i].exist = true;
        reg_list[i].caller_save = true; /* gdb defaults to true */
 
        feature = calloc(1, sizeof(struct reg_feature));
        if (feature) {
            feature->name = stm8_regs[i].feature;
            reg_list[i].feature = feature;
        } else
            LOG_ERROR("unable to allocate feature list");
    }
 
    return cache;
}
 
static void stm8_free_reg_cache(struct target *target)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    struct reg_cache *cache;
    struct reg *reg;
    unsigned int i;
 
    cache = stm8->core_cache;
 
    if (!cache)
        return;
 
    for (i = 0; i < cache->num_regs; i++) {
        reg = &cache->reg_list[i];
 
        free(reg->feature);
        free(reg->reg_data_type);
        free(reg->value);
    }
 
    free(cache->reg_list[0].arch_info);
    free(cache->reg_list);
    free(cache);
 
    stm8->core_cache = NULL;
}
 
static void stm8_deinit(struct target *target)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    free(stm8->hw_break_list);
 
    stm8_free_reg_cache(target);
 
    free(stm8);
}
 
static int stm8_arch_state(struct target *target)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    LOG_USER("target halted due to %s, pc: 0x%8.8" PRIx32 "",
        debug_reason_name(target),
        buf_get_u32(stm8->core_cache->reg_list[STM8_PC].value, 0, 32));
 
    return ERROR_OK;
}
 
static int stm8_step(struct target *target, int current,
        target_addr_t address, int handle_breakpoints)
{
    LOG_DEBUG("%x " TARGET_ADDR_FMT " %x",
        current, address, handle_breakpoints);
 
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
    struct breakpoint *breakpoint = NULL;
 
    if (target->state != TARGET_HALTED) {
        LOG_TARGET_ERROR(target, "not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* current = 1: continue on current pc, otherwise continue at <address> */
    if (!current) {
        buf_set_u32(stm8->core_cache->reg_list[STM8_PC].value, 0, 32, address);
        stm8->core_cache->reg_list[STM8_PC].dirty = true;
        stm8->core_cache->reg_list[STM8_PC].valid = true;
    }
 
    /* the front-end may request us not to handle breakpoints */
    if (handle_breakpoints) {
        breakpoint = breakpoint_find(target,
                buf_get_u32(stm8->core_cache->reg_list[STM8_PC].value, 0, 32));
        if (breakpoint)
            stm8_unset_breakpoint(target, breakpoint);
    }
 
    /* restore context */
    stm8_restore_context(target);
 
    /* configure single step mode */
    stm8_config_step(target, 1);
 
    target->debug_reason = DBG_REASON_SINGLESTEP;
 
    target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
 
    /* disable interrupts while stepping */
    if (!stm8->enable_step_irq)
        stm8_enable_interrupts(target, 0);
 
    /* exit debug mode */
    stm8_exit_debug(target);
 
    /* registers are now invalid */
    register_cache_invalidate(stm8->core_cache);
 
    LOG_DEBUG("target stepped ");
    stm8_debug_entry(target);
 
    if (breakpoint)
        stm8_set_breakpoint(target, breakpoint);
 
    target_call_event_callbacks(target, TARGET_EVENT_HALTED);
 
    return ERROR_OK;
}
 
static void stm8_enable_breakpoints(struct target *target)
{
    struct breakpoint *breakpoint = target->breakpoints;
 
    /* set any pending breakpoints */
    while (breakpoint) {
        if (!breakpoint->is_set)
            stm8_set_breakpoint(target, breakpoint);
        breakpoint = breakpoint->next;
    }
}
 
static int stm8_set_breakpoint(struct target *target,
        struct breakpoint *breakpoint)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    struct stm8_comparator *comparator_list = stm8->hw_break_list;
    int retval;
 
    if (breakpoint->is_set) {
        LOG_WARNING("breakpoint already set");
        return ERROR_OK;
    }
 
    if (breakpoint->type == BKPT_HARD) {
        int bp_num = 0;
 
        while (comparator_list[bp_num].used && (bp_num < stm8->num_hw_bpoints))
            bp_num++;
        if (bp_num >= stm8->num_hw_bpoints) {
            LOG_ERROR("Can not find free breakpoint register (bpid: %" PRIu32 ")",
                    breakpoint->unique_id);
            return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
        breakpoint_hw_set(breakpoint, bp_num);
        comparator_list[bp_num].used = true;
        comparator_list[bp_num].bp_value = breakpoint->address;
        comparator_list[bp_num].type = HWBRK_EXEC;
 
        retval = stm8_set_hwbreak(target, comparator_list);
        if (retval != ERROR_OK)
            return retval;
 
        LOG_DEBUG("bpid: %" PRIu32 ", bp_num %i bp_value 0x%" PRIx32 "",
                  breakpoint->unique_id,
                  bp_num, comparator_list[bp_num].bp_value);
    } else if (breakpoint->type == BKPT_SOFT) {
        LOG_DEBUG("bpid: %" PRIu32, breakpoint->unique_id);
        if (breakpoint->length == 1) {
            uint8_t verify = 0x55;
 
            retval = target_read_u8(target, breakpoint->address,
                    breakpoint->orig_instr);
            if (retval != ERROR_OK)
                return retval;
            retval = target_write_u8(target, breakpoint->address, STM8_BREAK);
            if (retval != ERROR_OK)
                return retval;
 
            retval = target_read_u8(target, breakpoint->address, &verify);
            if (retval != ERROR_OK)
                return retval;
            if (verify != STM8_BREAK) {
                LOG_ERROR("Unable to set breakpoint at address " TARGET_ADDR_FMT
                        " - check that memory is read/writable",
                        breakpoint->address);
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
            }
        } else {
            return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
        breakpoint->is_set = true;
    }
 
    return ERROR_OK;
}
 
static int stm8_add_breakpoint(struct target *target,
        struct breakpoint *breakpoint)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    int ret;
 
    if (breakpoint->type == BKPT_HARD) {
        if (stm8->num_hw_bpoints_avail < 1) {
            LOG_INFO("no hardware breakpoint available");
            return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
 
        ret = stm8_set_breakpoint(target, breakpoint);
        if (ret != ERROR_OK)
            return ret;
 
        stm8->num_hw_bpoints_avail--;
        return ERROR_OK;
    }
 
    ret = stm8_set_breakpoint(target, breakpoint);
    if (ret != ERROR_OK)
        return ret;
 
    return ERROR_OK;
}
 
static int stm8_unset_breakpoint(struct target *target,
        struct breakpoint *breakpoint)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
    struct stm8_comparator *comparator_list = stm8->hw_break_list;
    int retval;
 
    if (!breakpoint->is_set) {
        LOG_WARNING("breakpoint not set");
        return ERROR_OK;
    }
 
    if (breakpoint->type == BKPT_HARD) {
        int bp_num = breakpoint->number;
        if (bp_num >= stm8->num_hw_bpoints) {
            LOG_DEBUG("Invalid comparator number in breakpoint (bpid: %" PRIu32 ")",
                      breakpoint->unique_id);
            return ERROR_OK;
        }
        LOG_DEBUG("bpid: %" PRIu32 " - releasing hw: %d",
                breakpoint->unique_id,
                bp_num);
        comparator_list[bp_num].used = false;
        retval = stm8_set_hwbreak(target, comparator_list);
        if (retval != ERROR_OK)
            return retval;
    } else {
        /* restore original instruction (kept in target endianness) */
        LOG_DEBUG("bpid: %" PRIu32, breakpoint->unique_id);
        if (breakpoint->length == 1) {
            uint8_t current_instr;
 
            /* check that user program has not
              modified breakpoint instruction */
            retval = target_read_memory(target, breakpoint->address, 1, 1,
                    (uint8_t *)&current_instr);
            if (retval != ERROR_OK)
                return retval;
 
            if (current_instr == STM8_BREAK) {
                retval = target_write_memory(target, breakpoint->address, 1, 1,
                        breakpoint->orig_instr);
                if (retval != ERROR_OK)
                    return retval;
            }
        } else
            return ERROR_FAIL;
    }
    breakpoint->is_set = false;
 
    return ERROR_OK;
}
 
static int stm8_remove_breakpoint(struct target *target,
        struct breakpoint *breakpoint)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_TARGET_ERROR(target, "not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (breakpoint->is_set)
        stm8_unset_breakpoint(target, breakpoint);
 
    if (breakpoint->type == BKPT_HARD)
        stm8->num_hw_bpoints_avail++;
 
    return ERROR_OK;
}
 
static int stm8_set_watchpoint(struct target *target,
        struct watchpoint *watchpoint)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    struct stm8_comparator *comparator_list = stm8->hw_break_list;
    int wp_num = 0;
    int ret;
 
    if (watchpoint->is_set) {
        LOG_WARNING("watchpoint already set");
        return ERROR_OK;
    }
 
    while (comparator_list[wp_num].used && (wp_num < stm8->num_hw_bpoints))
        wp_num++;
    if (wp_num >= stm8->num_hw_bpoints) {
        LOG_ERROR("Can not find free hw breakpoint");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    if (watchpoint->length != 1) {
            LOG_ERROR("Only watchpoints of length 1 are supported");
            return ERROR_TARGET_UNALIGNED_ACCESS;
    }
 
    enum hw_break_type enable = 0;
 
    switch (watchpoint->rw) {
        case WPT_READ:
            enable = HWBRK_RD;
            break;
        case WPT_WRITE:
            enable = HWBRK_WR;
            break;
        case WPT_ACCESS:
            enable = HWBRK_ACC;
            break;
        default:
            LOG_ERROR("BUG: watchpoint->rw neither read, write nor access");
    }
 
    comparator_list[wp_num].used = true;
    comparator_list[wp_num].bp_value = watchpoint->address;
    comparator_list[wp_num].type = enable;
 
    ret = stm8_set_hwbreak(target, comparator_list);
    if (ret != ERROR_OK) {
        comparator_list[wp_num].used = false;
        return ret;
    }
 
    watchpoint_set(watchpoint, wp_num);
 
    LOG_DEBUG("wp_num %i bp_value 0x%" PRIx32 "",
            wp_num,
            comparator_list[wp_num].bp_value);
 
    return ERROR_OK;
}
 
static int stm8_add_watchpoint(struct target *target,
        struct watchpoint *watchpoint)
{
    int ret;
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (stm8->num_hw_bpoints_avail < 1) {
        LOG_INFO("no hardware watchpoints available");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    ret = stm8_set_watchpoint(target, watchpoint);
    if (ret != ERROR_OK)
        return ret;
 
    stm8->num_hw_bpoints_avail--;
    return ERROR_OK;
}
 
static void stm8_enable_watchpoints(struct target *target)
{
    struct watchpoint *watchpoint = target->watchpoints;
 
    /* set any pending watchpoints */
    while (watchpoint) {
        if (!watchpoint->is_set)
            stm8_set_watchpoint(target, watchpoint);
        watchpoint = watchpoint->next;
    }
}
 
static int stm8_unset_watchpoint(struct target *target,
        struct watchpoint *watchpoint)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
    struct stm8_comparator *comparator_list = stm8->hw_break_list;
 
    if (!watchpoint->is_set) {
        LOG_WARNING("watchpoint not set");
        return ERROR_OK;
    }
 
    int wp_num = watchpoint->number;
    if (wp_num >= stm8->num_hw_bpoints) {
        LOG_DEBUG("Invalid hw comparator number in watchpoint");
        return ERROR_OK;
    }
    comparator_list[wp_num].used = false;
    watchpoint->is_set = false;
 
    stm8_set_hwbreak(target, comparator_list);
 
    return ERROR_OK;
}
 
static int stm8_remove_watchpoint(struct target *target,
        struct watchpoint *watchpoint)
{
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_TARGET_ERROR(target, "not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (watchpoint->is_set)
        stm8_unset_watchpoint(target, watchpoint);
 
    stm8->num_hw_bpoints_avail++;
 
    return ERROR_OK;
}
 
static int stm8_examine(struct target *target)
{
    int retval;
    uint8_t csr1, csr2;
    /* get pointers to arch-specific information */
    struct stm8_common *stm8 = target_to_stm8(target);
    enum reset_types jtag_reset_config = jtag_get_reset_config();
 
    if (!target_was_examined(target)) {
        if (!stm8->swim_configured) {
            stm8->swim_configured = true;
            /*
                Now is the time to deassert reset if connect_under_reset.
                Releasing reset line will cause the option bytes to load.
                The core will still be stalled.
            */
            if (jtag_reset_config & RESET_CNCT_UNDER_SRST) {
                if (jtag_reset_config & RESET_SRST_NO_GATING)
                    stm8_reset_deassert(target);
                else
                    LOG_WARNING("\'srst_nogate\' reset_config option is required");
            }
        } else {
            LOG_INFO("trying to reconnect");
 
            retval = swim_reconnect();
            if (retval != ERROR_OK) {
                LOG_ERROR("reconnect failed");
                return ERROR_FAIL;
            }
 
            /* read dm_csrx control regs */
            retval = stm8_read_dm_csrx(target, &csr1, &csr2);
            if (retval != ERROR_OK) {
                LOG_ERROR("state query failed");
                return ERROR_FAIL;
            }
        }
 
        target_set_examined(target);
 
        return ERROR_OK;
    }
 
    return ERROR_OK;
}
 
static int stm8_blank_check_memory(struct target *target,
        struct target_memory_check_block *blocks, int num_blocks, uint8_t erased_value)
{
    struct working_area *erase_check_algorithm;
    struct reg_param reg_params[2];
    struct mem_param mem_params[2];
    struct stm8_algorithm stm8_info;
 
    static const uint8_t stm8_erase_check_code[] = {
#include "../../contrib/loaders/erase_check/stm8_erase_check.inc"
    };
 
    if (erased_value != 0xff) {
        LOG_ERROR("Erase value 0x%02" PRIx8 " not yet supported for STM8",
            erased_value);
        return ERROR_FAIL;
    }
 
    /* make sure we have a working area */
    if (target_alloc_working_area(target, sizeof(stm8_erase_check_code),
            &erase_check_algorithm) != ERROR_OK)
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 
    target_write_buffer(target, erase_check_algorithm->address,
            sizeof(stm8_erase_check_code), stm8_erase_check_code);
 
    stm8_info.common_magic = STM8_COMMON_MAGIC;
 
    init_mem_param(&mem_params[0], 0x0, 3, PARAM_OUT);
    buf_set_u32(mem_params[0].value, 0, 24, blocks[0].address);
 
    init_mem_param(&mem_params[1], 0x3, 3, PARAM_OUT);
    buf_set_u32(mem_params[1].value, 0, 24, blocks[0].size);
 
    init_reg_param(&reg_params[0], "a", 32, PARAM_IN_OUT);
    buf_set_u32(reg_params[0].value, 0, 32, erased_value);
 
    init_reg_param(&reg_params[1], "sp", 32, PARAM_OUT);
    buf_set_u32(reg_params[1].value, 0, 32, erase_check_algorithm->address);
 
    int retval = target_run_algorithm(target, 2, mem_params, 2, reg_params,
            erase_check_algorithm->address + 6,
            erase_check_algorithm->address + (sizeof(stm8_erase_check_code) - 1),
            10000, &stm8_info);
 
    if (retval == ERROR_OK)
        blocks[0].result = (*(reg_params[0].value) == 0xff);
 
    destroy_mem_param(&mem_params[0]);
    destroy_mem_param(&mem_params[1]);
    destroy_reg_param(&reg_params[0]);
    destroy_reg_param(&reg_params[1]);
 
    target_free_working_area(target, erase_check_algorithm);
 
    if (retval != ERROR_OK)
        return retval;
 
    return 1;   /* only one block has been checked */
}
 
static int stm8_checksum_memory(struct target *target, target_addr_t address,
        uint32_t count, uint32_t *checksum)
{
    /* let image_calculate_checksum() take care of business */
    return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
}
 
/* run to exit point. return error if exit point was not reached. */
static int stm8_run_and_wait(struct target *target, uint32_t entry_point,
        unsigned int timeout_ms, uint32_t exit_point, struct stm8_common *stm8)
{
    uint32_t pc;
    int retval;
    /* This code relies on the target specific resume() and
       poll()->debug_entry() sequence to write register values to the
       processor and the read them back */
    retval = target_resume(target, 0, entry_point, 0, 1);
    if (retval != ERROR_OK)
        return retval;
 
    retval = target_wait_state(target, TARGET_HALTED, timeout_ms);
    /* If the target fails to halt due to the breakpoint, force a halt */
    if (retval != ERROR_OK || target->state != TARGET_HALTED) {
        retval = target_halt(target);
        if (retval != ERROR_OK)
            return retval;
        retval = target_wait_state(target, TARGET_HALTED, 500);
        if (retval != ERROR_OK)
            return retval;
        return ERROR_TARGET_TIMEOUT;
    }
 
    pc = buf_get_u32(stm8->core_cache->reg_list[STM8_PC].value, 0, 32);
    if (exit_point && (pc != exit_point)) {
        LOG_DEBUG("failed algorithm halted at 0x%" PRIx32 " ", pc);
        return ERROR_TARGET_TIMEOUT;
    }
 
    return ERROR_OK;
}
 
static int stm8_run_algorithm(struct target *target, int num_mem_params,
        struct mem_param *mem_params, int num_reg_params,
        struct reg_param *reg_params, target_addr_t entry_point,
        target_addr_t exit_point, unsigned int timeout_ms, void *arch_info)
{
    struct stm8_common *stm8 = target_to_stm8(target);
 
    uint32_t context[STM8_NUM_REGS];
    int retval = ERROR_OK;
 
    LOG_DEBUG("Running algorithm");
 
    /* NOTE: stm8_run_algorithm requires that each
       algorithm uses a software breakpoint
       at the exit point */
 
    if (stm8->common_magic != STM8_COMMON_MAGIC) {
        LOG_ERROR("current target isn't a STM8 target");
        return ERROR_TARGET_INVALID;
    }
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* refresh core register cache */
    for (unsigned int i = 0; i < STM8_NUM_REGS; i++) {
        if (!stm8->core_cache->reg_list[i].valid)
            stm8->read_core_reg(target, i);
        context[i] = buf_get_u32(stm8->core_cache->reg_list[i].value, 0, 32);
    }
 
    for (int i = 0; i < num_mem_params; i++) {
        if (mem_params[i].direction == PARAM_IN)
            continue;
        retval = target_write_buffer(target, mem_params[i].address,
                mem_params[i].size, mem_params[i].value);
        if (retval != ERROR_OK)
            return retval;
    }
 
    for (int i = 0; i < num_reg_params; i++) {
        if (reg_params[i].direction == PARAM_IN)
            continue;
 
        struct reg *reg = register_get_by_name(stm8->core_cache,
                reg_params[i].reg_name, false);
 
        if (!reg) {
            LOG_ERROR("BUG: register '%s' not found", reg_params[i].reg_name);
            return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
        if (reg_params[i].size != 32) {
            LOG_ERROR("BUG: register '%s' size doesn't match reg_params[i].size",
                    reg_params[i].reg_name);
            return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
        stm8_set_core_reg(reg, reg_params[i].value);
    }
 
    retval = stm8_run_and_wait(target, entry_point,
            timeout_ms, exit_point, stm8);
 
    if (retval != ERROR_OK)
        return retval;
 
    for (int i = 0; i < num_mem_params; i++) {
        if (mem_params[i].direction != PARAM_OUT) {
            retval = target_read_buffer(target, mem_params[i].address,
                    mem_params[i].size, mem_params[i].value);
            if (retval != ERROR_OK)
                return retval;
        }
    }
 
    for (int i = 0; i < num_reg_params; i++) {
        if (reg_params[i].direction != PARAM_OUT) {
            struct reg *reg = register_get_by_name(stm8->core_cache,
                    reg_params[i].reg_name, false);
            if (!reg) {
                LOG_ERROR("BUG: register '%s' not found",
                        reg_params[i].reg_name);
                return ERROR_COMMAND_SYNTAX_ERROR;
            }
 
            if (reg_params[i].size != 32) {
                LOG_ERROR("BUG: register '%s' size doesn't match reg_params[i].size",
                        reg_params[i].reg_name);
                return ERROR_COMMAND_SYNTAX_ERROR;
            }
 
            buf_set_u32(reg_params[i].value,
                    0, 32, buf_get_u32(reg->value, 0, 32));
        }
    }
 
    /* restore everything we saved before */
    for (unsigned int i = 0; i < STM8_NUM_REGS; i++) {
        uint32_t regvalue;
        regvalue = buf_get_u32(stm8->core_cache->reg_list[i].value, 0, 32);
        if (regvalue != context[i]) {
            LOG_DEBUG("restoring register %s with value 0x%8.8" PRIx32,
                stm8->core_cache->reg_list[i].name, context[i]);
            buf_set_u32(stm8->core_cache->reg_list[i].value,
                    0, 32, context[i]);
            stm8->core_cache->reg_list[i].valid = true;
            stm8->core_cache->reg_list[i].dirty = true;
        }
    }
 
    return ERROR_OK;
}
 
static int stm8_jim_configure(struct target *target, struct jim_getopt_info *goi)
{
    struct stm8_common *stm8 = target_to_stm8(target);
    jim_wide w;
    int e;
    const char *arg;
 
    arg = Jim_GetString(goi->argv[0], NULL);
    if (!strcmp(arg, "-blocksize")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-blocksize ?bytes? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->blocksize = w;
        LOG_DEBUG("blocksize=%8.8" PRIx32, stm8->blocksize);
        return JIM_OK;
    }
    if (!strcmp(arg, "-flashstart")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-flashstart ?address? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->flashstart = w;
        LOG_DEBUG("flashstart=%8.8" PRIx32, stm8->flashstart);
        return JIM_OK;
    }
    if (!strcmp(arg, "-flashend")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-flashend ?address? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->flashend = w;
        LOG_DEBUG("flashend=%8.8" PRIx32, stm8->flashend);
        return JIM_OK;
    }
    if (!strcmp(arg, "-eepromstart")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-eepromstart ?address? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->eepromstart = w;
        LOG_DEBUG("eepromstart=%8.8" PRIx32, stm8->eepromstart);
        return JIM_OK;
    }
    if (!strcmp(arg, "-eepromend")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-eepromend ?address? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->eepromend = w;
        LOG_DEBUG("eepromend=%8.8" PRIx32, stm8->eepromend);
        return JIM_OK;
    }
    if (!strcmp(arg, "-optionstart")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-optionstart ?address? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->optionstart = w;
        LOG_DEBUG("optionstart=%8.8" PRIx32, stm8->optionstart);
        return JIM_OK;
    }
    if (!strcmp(arg, "-optionend")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        if (goi->argc == 0) {
            Jim_WrongNumArgs(goi->interp, goi->argc, goi->argv,
                    "-optionend ?address? ...");
            return JIM_ERR;
        }
 
        e = jim_getopt_wide(goi, &w);
        if (e != JIM_OK)
            return e;
 
        stm8->optionend = w;
        LOG_DEBUG("optionend=%8.8" PRIx32, stm8->optionend);
        return JIM_OK;
    }
    if (!strcmp(arg, "-enable_step_irq")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        stm8->enable_step_irq = true;
        LOG_DEBUG("enable_step_irq=%8.8x", stm8->enable_step_irq);
        return JIM_OK;
    }
    if (!strcmp(arg, "-enable_stm8l")) {
        e = jim_getopt_string(goi, &arg, NULL);
        if (e != JIM_OK)
            return e;
 
        stm8->enable_stm8l = true;
        LOG_DEBUG("enable_stm8l=%8.8x", stm8->enable_stm8l);
        stm8_init_flash_regs(stm8->enable_stm8l, stm8);
        return JIM_OK;
    }
    return JIM_CONTINUE;
}
 
COMMAND_HANDLER(stm8_handle_enable_step_irq_command)
{
    const char *msg;
    struct target *target = get_current_target(CMD_CTX);
    struct stm8_common *stm8 = target_to_stm8(target);
    bool enable = stm8->enable_step_irq;
 
    if (CMD_ARGC > 0) {
        COMMAND_PARSE_ENABLE(CMD_ARGV[0], enable);
        stm8->enable_step_irq = enable;
    }
    msg = stm8->enable_step_irq ? "enabled" : "disabled";
    command_print(CMD, "enable_step_irq = %s", msg);
    return ERROR_OK;
}
 
COMMAND_HANDLER(stm8_handle_enable_stm8l_command)
{
    const char *msg;
    struct target *target = get_current_target(CMD_CTX);
    struct stm8_common *stm8 = target_to_stm8(target);
    bool enable = stm8->enable_stm8l;
 
    if (CMD_ARGC > 0) {
        COMMAND_PARSE_ENABLE(CMD_ARGV[0], enable);
        stm8->enable_stm8l = enable;
    }
    msg = stm8->enable_stm8l ? "enabled" : "disabled";
    command_print(CMD, "enable_stm8l = %s", msg);
    stm8_init_flash_regs(stm8->enable_stm8l, stm8);
    return ERROR_OK;
}
 
static const struct command_registration stm8_exec_command_handlers[] = {
    {
        .name = "enable_step_irq",
        .handler = stm8_handle_enable_step_irq_command,
        .mode = COMMAND_ANY,
        .help = "Enable/disable irq handling during step",
        .usage = "[1/0]",
    },
    {
        .name = "enable_stm8l",
        .handler = stm8_handle_enable_stm8l_command,
        .mode = COMMAND_ANY,
        .help = "Enable/disable STM8L flash programming",
        .usage = "[1/0]",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration stm8_command_handlers[] = {
    {
        .name = "stm8",
        .mode = COMMAND_ANY,
        .help = "stm8 command group",
        .usage = "",
        .chain = stm8_exec_command_handlers,
    },
    COMMAND_REGISTRATION_DONE
};
 
struct target_type stm8_target = {
    .name = "stm8",
 
    .poll = stm8_poll,
    .arch_state = stm8_arch_state,
 
    .halt = stm8_halt,
    .resume = stm8_resume,
    .step = stm8_step,
 
    .assert_reset = stm8_reset_assert,
    .deassert_reset = stm8_reset_deassert,
 
    .get_gdb_arch = stm8_get_gdb_arch,
    .get_gdb_reg_list = stm8_get_gdb_reg_list,
 
    .read_memory = stm8_read_memory,
    .write_memory = stm8_write_memory,
    .checksum_memory = stm8_checksum_memory,
    .blank_check_memory = stm8_blank_check_memory,
 
    .run_algorithm = stm8_run_algorithm,
 
    .add_breakpoint = stm8_add_breakpoint,
    .remove_breakpoint = stm8_remove_breakpoint,
    .add_watchpoint = stm8_add_watchpoint,
    .remove_watchpoint = stm8_remove_watchpoint,
 
    .commands = stm8_command_handlers,
    .target_create = stm8_target_create,
    .init_target = stm8_init,
    .examine = stm8_examine,
 
    .deinit_target = stm8_deinit,
    .target_jim_configure = stm8_jim_configure,
};