at91samd.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2013 by Andrey Yurovsky                                 *
 *   Andrey Yurovsky <yurovsky@gmail.com>                                  *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "imp.h"
#include "helper/binarybuffer.h"
 
#include <helper/time_support.h>
#include <jtag/jtag.h>
#include <target/cortex_m.h>
 
#define SAMD_NUM_PROT_BLOCKS    16
#define SAMD_PAGE_SIZE_MAX  1024
 
#define SAMD_FLASH          ((uint32_t)0x00000000)  /* physical Flash memory */
#define SAMD_USER_ROW       ((uint32_t)0x00804000)  /* User Row of Flash */
#define SAMD_PAC1           0x41000000  /* Peripheral Access Control 1 */
#define SAMD_DSU            0x41002000  /* Device Service Unit */
#define SAMD_NVMCTRL        0x41004000  /* Non-volatile memory controller */
 
#define SAMD_DSU_STATUSA        1               /* DSU status register */
#define SAMD_DSU_DID        0x18        /* Device ID register */
#define SAMD_DSU_CTRL_EXT   0x100       /* CTRL register, external access */
 
#define SAMD_NVMCTRL_CTRLA      0x00    /* NVM control A register */
#define SAMD_NVMCTRL_CTRLB      0x04    /* NVM control B register */
#define SAMD_NVMCTRL_PARAM      0x08    /* NVM parameters register */
#define SAMD_NVMCTRL_INTFLAG    0x14    /* NVM Interrupt Flag Status & Clear */
#define SAMD_NVMCTRL_STATUS     0x18    /* NVM status register */
#define SAMD_NVMCTRL_ADDR       0x1C    /* NVM address register */
#define SAMD_NVMCTRL_LOCK       0x20    /* NVM Lock section register */
 
#define SAMD_CMDEX_KEY      0xA5UL
#define SAMD_NVM_CMD(n)     ((SAMD_CMDEX_KEY << 8) | (n & 0x7F))
 
/* NVMCTRL commands.  See Table 20-4 in 42129F–SAM–10/2013 */
#define SAMD_NVM_CMD_ER     0x02        /* Erase Row */
#define SAMD_NVM_CMD_WP     0x04        /* Write Page */
#define SAMD_NVM_CMD_EAR    0x05        /* Erase Auxiliary Row */
#define SAMD_NVM_CMD_WAP    0x06        /* Write Auxiliary Page */
#define SAMD_NVM_CMD_LR     0x40        /* Lock Region */
#define SAMD_NVM_CMD_UR     0x41        /* Unlock Region */
#define SAMD_NVM_CMD_SPRM   0x42        /* Set Power Reduction Mode */
#define SAMD_NVM_CMD_CPRM   0x43        /* Clear Power Reduction Mode */
#define SAMD_NVM_CMD_PBC    0x44        /* Page Buffer Clear */
#define SAMD_NVM_CMD_SSB    0x45        /* Set Security Bit */
#define SAMD_NVM_CMD_INVALL 0x46        /* Invalidate all caches */
 
/* NVMCTRL bits */
#define SAMD_NVM_CTRLB_MANW 0x80
 
/* NVMCTRL_INTFLAG bits */
#define SAMD_NVM_INTFLAG_READY 0x01
 
/* Known identifiers */
#define SAMD_PROCESSOR_M0   0x01
#define SAMD_FAMILY_D       0x00
#define SAMD_FAMILY_L       0x01
#define SAMD_FAMILY_C       0x02
#define SAMD_SERIES_20      0x00
#define SAMD_SERIES_21      0x01
#define SAMD_SERIES_22      0x02
#define SAMD_SERIES_10      0x02
#define SAMD_SERIES_11      0x03
#define SAMD_SERIES_09      0x04
 
/* Device ID macros */
#define SAMD_GET_PROCESSOR(id) (id >> 28)
#define SAMD_GET_FAMILY(id) (((id >> 23) & 0x1F))
#define SAMD_GET_SERIES(id) (((id >> 16) & 0x3F))
#define SAMD_GET_DEVSEL(id) (id & 0xFF)
 
/* Bits to mask out lockbits in user row */
#define NVMUSERROW_LOCKBIT_MASK 0x0000FFFFFFFFFFFFULL
 
struct samd_part {
    uint8_t id;
    const char *name;
    uint32_t flash_kb;
    uint32_t ram_kb;
};
 
/* Known SAMD09 parts. DID reset values missing in RM, see
 * https://github.com/avrxml/asf/blob/master/sam0/utils/cmsis/samd09/include/ */
static const struct samd_part samd09_parts[] = {
    { 0x0, "SAMD09D14A", 16, 4 },
    { 0x7, "SAMD09C13A", 8, 4 },
};
 
/* Known SAMD10 parts */
static const struct samd_part samd10_parts[] = {
    { 0x0, "SAMD10D14AMU", 16, 4 },
    { 0x1, "SAMD10D13AMU", 8, 4 },
    { 0x2, "SAMD10D12AMU", 4, 4 },
    { 0x3, "SAMD10D14ASU", 16, 4 },
    { 0x4, "SAMD10D13ASU", 8, 4 },
    { 0x5, "SAMD10D12ASU", 4, 4 },
    { 0x6, "SAMD10C14A", 16, 4 },
    { 0x7, "SAMD10C13A", 8, 4 },
    { 0x8, "SAMD10C12A", 4, 4 },
};
 
/* Known SAMD11 parts */
static const struct samd_part samd11_parts[] = {
    { 0x0, "SAMD11D14AM", 16, 4 },
    { 0x1, "SAMD11D13AMU", 8, 4 },
    { 0x2, "SAMD11D12AMU", 4, 4 },
    { 0x3, "SAMD11D14ASS", 16, 4 },
    { 0x4, "SAMD11D13ASU", 8, 4 },
    { 0x5, "SAMD11D12ASU", 4, 4 },
    { 0x6, "SAMD11C14A", 16, 4 },
    { 0x7, "SAMD11C13A", 8, 4 },
    { 0x8, "SAMD11C12A", 4, 4 },
    { 0x9, "SAMD11D14AU", 16, 4 },
};
 
/* Known SAMD20 parts. See Table 12-8 in 42129F–SAM–10/2013 */
static const struct samd_part samd20_parts[] = {
    { 0x0, "SAMD20J18A", 256, 32 },
    { 0x1, "SAMD20J17A", 128, 16 },
    { 0x2, "SAMD20J16A", 64, 8 },
    { 0x3, "SAMD20J15A", 32, 4 },
    { 0x4, "SAMD20J14A", 16, 2 },
    { 0x5, "SAMD20G18A", 256, 32 },
    { 0x6, "SAMD20G17A", 128, 16 },
    { 0x7, "SAMD20G16A", 64, 8 },
    { 0x8, "SAMD20G15A", 32, 4 },
    { 0x9, "SAMD20G14A", 16, 2 },
    { 0xA, "SAMD20E18A", 256, 32 },
    { 0xB, "SAMD20E17A", 128, 16 },
    { 0xC, "SAMD20E16A", 64, 8 },
    { 0xD, "SAMD20E15A", 32, 4 },
    { 0xE, "SAMD20E14A", 16, 2 },
};
 
/* Known SAMD21 parts. */
static const struct samd_part samd21_parts[] = {
    { 0x0, "SAMD21J18A", 256, 32 },
    { 0x1, "SAMD21J17A", 128, 16 },
    { 0x2, "SAMD21J16A", 64, 8 },
    { 0x3, "SAMD21J15A", 32, 4 },
    { 0x4, "SAMD21J14A", 16, 2 },
    { 0x5, "SAMD21G18A", 256, 32 },
    { 0x6, "SAMD21G17A", 128, 16 },
    { 0x7, "SAMD21G16A", 64, 8 },
    { 0x8, "SAMD21G15A", 32, 4 },
    { 0x9, "SAMD21G14A", 16, 2 },
    { 0xA, "SAMD21E18A", 256, 32 },
    { 0xB, "SAMD21E17A", 128, 16 },
    { 0xC, "SAMD21E16A", 64, 8 },
    { 0xD, "SAMD21E15A", 32, 4 },
    { 0xE, "SAMD21E14A", 16, 2 },
 
    /* SAMR21 parts have integrated SAMD21 with a radio */
    { 0x18, "SAMR21G19A", 256, 32 }, /* with 512k of serial flash */
    { 0x19, "SAMR21G18A", 256, 32 },
    { 0x1A, "SAMR21G17A", 128, 32 },
    { 0x1B, "SAMR21G16A",  64, 16 },
    { 0x1C, "SAMR21E18A", 256, 32 },
    { 0x1D, "SAMR21E17A", 128, 32 },
    { 0x1E, "SAMR21E16A",  64, 16 },
 
    /* SAMD21 B Variants (Table 3-7 from rev I of datasheet) */
    { 0x20, "SAMD21J16B", 64, 8 },
    { 0x21, "SAMD21J15B", 32, 4 },
    { 0x23, "SAMD21G16B", 64, 8 },
    { 0x24, "SAMD21G15B", 32, 4 },
    { 0x26, "SAMD21E16B", 64, 8 },
    { 0x27, "SAMD21E15B", 32, 4 },
 
    /* SAMD21 D and L Variants (from Errata)
       http://ww1.microchip.com/downloads/en/DeviceDoc/
       SAM-D21-Family-Silicon-Errata-and-DataSheet-Clarification-DS80000760D.pdf */
    { 0x55, "SAMD21E16BU", 64, 8 },
    { 0x56, "SAMD21E15BU", 32, 4 },
    { 0x57, "SAMD21G16L", 64, 8 },
    { 0x3E, "SAMD21E16L", 64, 8 },
    { 0x3F, "SAMD21E15L", 32, 4 },
    { 0x62, "SAMD21E16CU", 64, 8 },
    { 0x63, "SAMD21E15CU", 32, 4 },
    { 0x92, "SAMD21J17D", 128, 16 },
    { 0x93, "SAMD21G17D", 128, 16 },
    { 0x94, "SAMD21E17D", 128, 16 },
    { 0x95, "SAMD21E17DU", 128, 16 },
    { 0x96, "SAMD21G17L", 128, 16 },
    { 0x97, "SAMD21E17L", 128, 16 },
 
    /* Known SAMDA1 parts.
       SAMD-A1 series uses the same series identifier like the SAMD21
       taken from http://ww1.microchip.com/downloads/en/DeviceDoc/40001895A.pdf (pages 14-17) */
    { 0x29, "SAMDA1J16A", 64, 8 },
    { 0x2A, "SAMDA1J15A", 32, 4 },
    { 0x2B, "SAMDA1J14A", 16, 4 },
    { 0x2C, "SAMDA1G16A", 64, 8 },
    { 0x2D, "SAMDA1G15A", 32, 4 },
    { 0x2E, "SAMDA1G14A", 16, 4 },
    { 0x2F, "SAMDA1E16A", 64, 8 },
    { 0x30, "SAMDA1E15A", 32, 4 },
    { 0x31, "SAMDA1E14A", 16, 4 },
    { 0x64, "SAMDA1J16B", 64, 8 },
    { 0x65, "SAMDA1J15B", 32, 4 },
    { 0x66, "SAMDA1J14B", 16, 4 },
    { 0x67, "SAMDA1G16B", 64, 8 },
    { 0x68, "SAMDA1G15B", 32, 4 },
    { 0x69, "SAMDA1G14B", 16, 4 },
    { 0x6A, "SAMDA1E16B", 64, 8 },
    { 0x6B, "SAMDA1E15B", 32, 4 },
    { 0x6C, "SAMDA1E14B", 16, 4 },
};
 
/* Known SAML21 parts. */
static const struct samd_part saml21_parts[] = {
    { 0x00, "SAML21J18A", 256, 32 },
    { 0x01, "SAML21J17A", 128, 16 },
    { 0x02, "SAML21J16A", 64, 8 },
    { 0x05, "SAML21G18A", 256, 32 },
    { 0x06, "SAML21G17A", 128, 16 },
    { 0x07, "SAML21G16A", 64, 8 },
    { 0x0A, "SAML21E18A", 256, 32 },
    { 0x0B, "SAML21E17A", 128, 16 },
    { 0x0C, "SAML21E16A", 64, 8 },
    { 0x0D, "SAML21E15A", 32, 4 },
    { 0x0F, "SAML21J18B", 256, 32 },
    { 0x10, "SAML21J17B", 128, 16 },
    { 0x11, "SAML21J16B", 64, 8 },
    { 0x14, "SAML21G18B", 256, 32 },
    { 0x15, "SAML21G17B", 128, 16 },
    { 0x16, "SAML21G16B", 64, 8 },
    { 0x19, "SAML21E18B", 256, 32 },
    { 0x1A, "SAML21E17B", 128, 16 },
    { 0x1B, "SAML21E16B", 64, 8 },
    { 0x1C, "SAML21E15B", 32, 4 },
 
    /* SAMR30 parts have integrated SAML21 with a radio */
    { 0x1E, "SAMR30G18A", 256, 32 },
    { 0x1F, "SAMR30E18A", 256, 32 },
 
    /* SAMR34/R35 parts have integrated SAML21 with a lora radio */
    { 0x28, "SAMR34J18", 256, 40 },
    { 0x29, "SAMR34J17", 128, 24 },
    { 0x2A, "SAMR34J16", 64, 12 },
    { 0x2B, "SAMR35J18", 256, 40 },
    { 0x2C, "SAMR35J17", 128, 24 },
    { 0x2D, "SAMR35J16", 64, 12 },
};
 
/* Known SAML22 parts. */
static const struct samd_part saml22_parts[] = {
    { 0x00, "SAML22N18A", 256, 32 },
    { 0x01, "SAML22N17A", 128, 16 },
    { 0x02, "SAML22N16A", 64, 8 },
    { 0x05, "SAML22J18A", 256, 32 },
    { 0x06, "SAML22J17A", 128, 16 },
    { 0x07, "SAML22J16A", 64, 8 },
    { 0x0A, "SAML22G18A", 256, 32 },
    { 0x0B, "SAML22G17A", 128, 16 },
    { 0x0C, "SAML22G16A", 64, 8 },
};
 
/* Known SAMC20 parts. */
static const struct samd_part samc20_parts[] = {
    { 0x00, "SAMC20J18A", 256, 32 },
    { 0x01, "SAMC20J17A", 128, 16 },
    { 0x02, "SAMC20J16A", 64, 8 },
    { 0x03, "SAMC20J15A", 32, 4 },
    { 0x05, "SAMC20G18A", 256, 32 },
    { 0x06, "SAMC20G17A", 128, 16 },
    { 0x07, "SAMC20G16A", 64, 8 },
    { 0x08, "SAMC20G15A", 32, 4 },
    { 0x0A, "SAMC20E18A", 256, 32 },
    { 0x0B, "SAMC20E17A", 128, 16 },
    { 0x0C, "SAMC20E16A", 64, 8 },
    { 0x0D, "SAMC20E15A", 32, 4 },
    { 0x20, "SAMC20N18A", 256, 32 },
    { 0x21, "SAMC20N17A", 128, 16 },
};
 
/* Known SAMC21 parts. */
static const struct samd_part samc21_parts[] = {
    { 0x00, "SAMC21J18A", 256, 32 },
    { 0x01, "SAMC21J17A", 128, 16 },
    { 0x02, "SAMC21J16A", 64, 8 },
    { 0x03, "SAMC21J15A", 32, 4 },
    { 0x05, "SAMC21G18A", 256, 32 },
    { 0x06, "SAMC21G17A", 128, 16 },
    { 0x07, "SAMC21G16A", 64, 8 },
    { 0x08, "SAMC21G15A", 32, 4 },
    { 0x0A, "SAMC21E18A", 256, 32 },
    { 0x0B, "SAMC21E17A", 128, 16 },
    { 0x0C, "SAMC21E16A", 64, 8 },
    { 0x0D, "SAMC21E15A", 32, 4 },
    { 0x20, "SAMC21N18A", 256, 32 },
    { 0x21, "SAMC21N17A", 128, 16 },
};
 
/* Each family of parts contains a parts table in the DEVSEL field of DID.  The
 * processor ID, family ID, and series ID are used to determine which exact
 * family this is and then we can use the corresponding table. */
struct samd_family {
    uint8_t processor;
    uint8_t family;
    uint8_t series;
    const struct samd_part *parts;
    size_t num_parts;
    uint64_t nvm_userrow_res_mask; /* protect bits which are reserved, 0 -> protect */
};
 
/* Known SAMD families */
static const struct samd_family samd_families[] = {
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_D, SAMD_SERIES_20,
        samd20_parts, ARRAY_SIZE(samd20_parts),
        0xFFFF01FFFE01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_D, SAMD_SERIES_21,
        samd21_parts, ARRAY_SIZE(samd21_parts),
        0xFFFF01FFFE01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_D, SAMD_SERIES_09,
        samd09_parts, ARRAY_SIZE(samd09_parts),
        0xFFFF01FFFE01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_D, SAMD_SERIES_10,
        samd10_parts, ARRAY_SIZE(samd10_parts),
        0xFFFF01FFFE01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_D, SAMD_SERIES_11,
        samd11_parts, ARRAY_SIZE(samd11_parts),
        0xFFFF01FFFE01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_L, SAMD_SERIES_21,
        saml21_parts, ARRAY_SIZE(saml21_parts),
        0xFFFF03FFFC01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_L, SAMD_SERIES_22,
        saml22_parts, ARRAY_SIZE(saml22_parts),
        0xFFFF03FFFC01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_C, SAMD_SERIES_20,
        samc20_parts, ARRAY_SIZE(samc20_parts),
        0xFFFF03FFFC01FF77ULL },
    { SAMD_PROCESSOR_M0, SAMD_FAMILY_C, SAMD_SERIES_21,
        samc21_parts, ARRAY_SIZE(samc21_parts),
        0xFFFF03FFFC01FF77ULL },
};
 
struct samd_info {
    uint32_t page_size;
    int num_pages;
    int sector_size;
    int prot_block_size;
 
    bool probed;
    struct target *target;
};
 
 
static const struct samd_family *samd_find_family(uint32_t id)
{
    uint8_t processor = SAMD_GET_PROCESSOR(id);
    uint8_t family = SAMD_GET_FAMILY(id);
    uint8_t series = SAMD_GET_SERIES(id);
 
    for (unsigned i = 0; i < ARRAY_SIZE(samd_families); i++) {
        if (samd_families[i].processor == processor &&
            samd_families[i].series == series &&
            samd_families[i].family == family)
            return &samd_families[i];
    }
 
    return NULL;
}
 
static const struct samd_part *samd_find_part(uint32_t id)
{
    uint8_t devsel = SAMD_GET_DEVSEL(id);
    const struct samd_family *family = samd_find_family(id);
    if (!family)
        return NULL;
 
    for (unsigned i = 0; i < family->num_parts; i++) {
        if (family->parts[i].id == devsel)
            return &family->parts[i];
    }
 
    return NULL;
}
 
static int samd_protect_check(struct flash_bank *bank)
{
    int res;
    uint16_t lock;
 
    res = target_read_u16(bank->target,
            SAMD_NVMCTRL + SAMD_NVMCTRL_LOCK, &lock);
    if (res != ERROR_OK)
        return res;
 
    /* Lock bits are active-low */
    for (unsigned int prot_block = 0; prot_block < bank->num_prot_blocks; prot_block++)
        bank->prot_blocks[prot_block].is_protected = !(lock & (1u<<prot_block));
 
    return ERROR_OK;
}
 
static int samd_get_flash_page_info(struct target *target,
        uint32_t *sizep, int *nump)
{
    int res;
    uint32_t param;
 
    res = target_read_u32(target, SAMD_NVMCTRL + SAMD_NVMCTRL_PARAM, &param);
    if (res == ERROR_OK) {
        /* The PSZ field (bits 18:16) indicate the page size bytes as 2^(3+n)
         * so 0 is 8KB and 7 is 1024KB. */
        if (sizep)
            *sizep = (8 << ((param >> 16) & 0x7));
        /* The NVMP field (bits 15:0) indicates the total number of pages */
        if (nump)
            *nump = param & 0xFFFF;
    } else {
        LOG_ERROR("Couldn't read NVM Parameters register");
    }
 
    return res;
}
 
static int samd_probe(struct flash_bank *bank)
{
    uint32_t id;
    int res;
    struct samd_info *chip = (struct samd_info *)bank->driver_priv;
    const struct samd_part *part;
 
    if (chip->probed)
        return ERROR_OK;
 
    res = target_read_u32(bank->target, SAMD_DSU + SAMD_DSU_DID, &id);
    if (res != ERROR_OK) {
        LOG_ERROR("Couldn't read Device ID register");
        return res;
    }
 
    part = samd_find_part(id);
    if (!part) {
        LOG_ERROR("Couldn't find part corresponding to DID %08" PRIx32, id);
        return ERROR_FAIL;
    }
 
    bank->size = part->flash_kb * 1024;
 
    res = samd_get_flash_page_info(bank->target, &chip->page_size,
            &chip->num_pages);
    if (res != ERROR_OK) {
        LOG_ERROR("Couldn't determine Flash page size");
        return res;
    }
 
    /* Sanity check: the total flash size in the DSU should match the page size
     * multiplied by the number of pages. */
    if (bank->size != chip->num_pages * chip->page_size) {
        LOG_WARNING("SAMD: bank size doesn't match NVM parameters. "
                "Identified %" PRIu32 "KB Flash but NVMCTRL reports %u %" PRIu32 "B pages",
                part->flash_kb, chip->num_pages, chip->page_size);
    }
 
    /* Erase granularity = 1 row = 4 pages */
    chip->sector_size = chip->page_size * 4;
 
    /* Allocate the sector table */
    bank->num_sectors = chip->num_pages / 4;
    bank->sectors = alloc_block_array(0, chip->sector_size, bank->num_sectors);
    if (!bank->sectors)
        return ERROR_FAIL;
 
    /* 16 protection blocks per device */
    chip->prot_block_size = bank->size / SAMD_NUM_PROT_BLOCKS;
 
    /* Allocate the table of protection blocks */
    bank->num_prot_blocks = SAMD_NUM_PROT_BLOCKS;
    bank->prot_blocks = alloc_block_array(0, chip->prot_block_size, bank->num_prot_blocks);
    if (!bank->prot_blocks)
        return ERROR_FAIL;
 
    samd_protect_check(bank);
 
    /* Done */
    chip->probed = true;
 
    LOG_INFO("SAMD MCU: %s (%" PRIu32 "KB Flash, %" PRIu32 "KB RAM)", part->name,
            part->flash_kb, part->ram_kb);
 
    return ERROR_OK;
}
 
static int samd_check_error(struct target *target)
{
    int ret, ret2;
    uint8_t intflag;
    uint16_t status;
    int timeout_ms = 1000;
    int64_t ts_start = timeval_ms();
 
    do {
        ret = target_read_u8(target,
            SAMD_NVMCTRL + SAMD_NVMCTRL_INTFLAG, &intflag);
        if (ret != ERROR_OK) {
            LOG_ERROR("Can't read NVM intflag");
            return ret;
        }
        if (intflag & SAMD_NVM_INTFLAG_READY)
            break;
        keep_alive();
    } while (timeval_ms() - ts_start < timeout_ms);
 
    if (!(intflag & SAMD_NVM_INTFLAG_READY)) {
        LOG_ERROR("SAMD: NVM programming timed out");
        return ERROR_FLASH_OPERATION_FAILED;
    }
 
    ret = target_read_u16(target,
            SAMD_NVMCTRL + SAMD_NVMCTRL_STATUS, &status);
    if (ret != ERROR_OK) {
        LOG_ERROR("Can't read NVM status");
        return ret;
    }
 
    if ((status & 0x001C) == 0)
        return ERROR_OK;
 
    if (status & (1 << 4)) { /* NVME */
        LOG_ERROR("SAMD: NVM Error");
        ret = ERROR_FLASH_OPERATION_FAILED;
    }
 
    if (status & (1 << 3)) { /* LOCKE */
        LOG_ERROR("SAMD: NVM lock error");
        ret = ERROR_FLASH_PROTECTED;
    }
 
    if (status & (1 << 2)) { /* PROGE */
        LOG_ERROR("SAMD: NVM programming error");
        ret = ERROR_FLASH_OPER_UNSUPPORTED;
    }
 
    /* Clear the error conditions by writing a one to them */
    ret2 = target_write_u16(target,
            SAMD_NVMCTRL + SAMD_NVMCTRL_STATUS, status);
    if (ret2 != ERROR_OK)
        LOG_ERROR("Can't clear NVM error conditions");
 
    return ret;
}
 
static int samd_issue_nvmctrl_command(struct target *target, uint16_t cmd)
{
    int res;
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* Issue the NVM command */
    /* 32-bit write is used to ensure atomic operation on ST-Link */
    res = target_write_u32(target,
            SAMD_NVMCTRL + SAMD_NVMCTRL_CTRLA, SAMD_NVM_CMD(cmd));
    if (res != ERROR_OK)
        return res;
 
    /* Check to see if the NVM command resulted in an error condition. */
    return samd_check_error(target);
}
 
static int samd_erase_row(struct target *target, uint32_t address)
{
    int res;
 
    /* Set an address contained in the row to be erased */
    res = target_write_u32(target,
            SAMD_NVMCTRL + SAMD_NVMCTRL_ADDR, address >> 1);
 
    /* Issue the Erase Row command to erase that row. */
    if (res == ERROR_OK)
        res = samd_issue_nvmctrl_command(target,
                address == SAMD_USER_ROW ? SAMD_NVM_CMD_EAR : SAMD_NVM_CMD_ER);
 
    if (res != ERROR_OK)  {
        LOG_ERROR("Failed to erase row containing %08" PRIx32, address);
        return ERROR_FAIL;
    }
 
    return ERROR_OK;
}
 
static int samd_get_reservedmask(struct target *target, uint64_t *mask)
{
    int res;
    /* Get the devicetype */
    uint32_t id;
    res = target_read_u32(target, SAMD_DSU + SAMD_DSU_DID, &id);
    if (res != ERROR_OK) {
        LOG_ERROR("Couldn't read Device ID register");
        return res;
    }
    const struct samd_family *family;
    family = samd_find_family(id);
    if (!family) {
        LOG_ERROR("Couldn't determine device family");
        return ERROR_FAIL;
    }
    *mask = family->nvm_userrow_res_mask;
    return ERROR_OK;
}
 
static int read_userrow(struct target *target, uint64_t *userrow)
{
    int res;
    uint8_t buffer[8];
 
    res = target_read_memory(target, SAMD_USER_ROW, 4, 2, buffer);
    if (res != ERROR_OK)
        return res;
 
    *userrow = target_buffer_get_u64(target, buffer);
    return ERROR_OK;
}
 
static int samd_modify_user_row_masked(struct target *target,
        uint64_t value_input, uint64_t value_mask)
{
    int res;
    uint32_t nvm_ctrlb;
    bool manual_wp = true;
 
    /* Retrieve the MCU's page size, in bytes. This is also the size of the
     * entire User Row. */
    uint32_t page_size;
    res = samd_get_flash_page_info(target, &page_size, NULL);
    if (res != ERROR_OK) {
        LOG_ERROR("Couldn't determine Flash page size");
        return res;
    }
 
    /* Make sure the size is sane. */
    assert(page_size <= SAMD_PAGE_SIZE_MAX &&
        page_size >= sizeof(value_input));
 
    uint8_t buf[SAMD_PAGE_SIZE_MAX];
    /* Read the user row (comprising one page) by words. */
    res = target_read_memory(target, SAMD_USER_ROW, 4, page_size / 4, buf);
    if (res != ERROR_OK)
        return res;
 
    uint64_t value_device;
    res = read_userrow(target, &value_device);
    if (res != ERROR_OK)
        return res;
    uint64_t value_new = (value_input & value_mask) | (value_device & ~value_mask);
 
    /* We will need to erase before writing if the new value needs a '1' in any
     * position for which the current value had a '0'.  Otherwise we can avoid
     * erasing. */
    if ((~value_device) & value_new) {
        res = samd_erase_row(target, SAMD_USER_ROW);
        if (res != ERROR_OK) {
            LOG_ERROR("Couldn't erase user row");
            return res;
        }
    }
 
    /* Modify */
    target_buffer_set_u64(target, buf, value_new);
 
    /* Write the page buffer back out to the target. */
    res = target_write_memory(target, SAMD_USER_ROW, 4, page_size / 4, buf);
    if (res != ERROR_OK)
        return res;
 
    /* Check if we need to do manual page write commands */
    res = target_read_u32(target, SAMD_NVMCTRL + SAMD_NVMCTRL_CTRLB, &nvm_ctrlb);
    if (res == ERROR_OK)
        manual_wp = (nvm_ctrlb & SAMD_NVM_CTRLB_MANW) != 0;
    else {
        LOG_ERROR("Read of NVM register CTRKB failed.");
        return ERROR_FAIL;
    }
    if (manual_wp) {
        /* Trigger flash write */
        res = samd_issue_nvmctrl_command(target, SAMD_NVM_CMD_WAP);
    } else {
        res = samd_check_error(target);
    }
 
    return res;
}
 
static int samd_modify_user_row(struct target *target, uint64_t value,
        uint8_t startb, uint8_t endb)
{
    uint64_t mask = 0;
    int i;
    for (i = startb ; i <= endb ; i++)
        mask |= ((uint64_t)1) << i;
 
    return samd_modify_user_row_masked(target, value << startb, mask);
}
 
static int samd_protect(struct flash_bank *bank, int set,
        unsigned int first, unsigned int last)
{
    int res = ERROR_OK;
 
    /* We can issue lock/unlock region commands with the target running but
     * the settings won't persist unless we're able to modify the LOCK regions
     * and that requires the target to be halted. */
    if (bank->target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    for (unsigned int prot_block = first; prot_block <= last; prot_block++) {
        if (set != bank->prot_blocks[prot_block].is_protected) {
            /* Load an address that is within this protection block (we use offset 0) */
            res = target_write_u32(bank->target,
                            SAMD_NVMCTRL + SAMD_NVMCTRL_ADDR,
                            bank->prot_blocks[prot_block].offset >> 1);
            if (res != ERROR_OK)
                goto exit;
 
            /* Tell the controller to lock that block */
            res = samd_issue_nvmctrl_command(bank->target,
                    set ? SAMD_NVM_CMD_LR : SAMD_NVM_CMD_UR);
            if (res != ERROR_OK)
                goto exit;
        }
    }
 
    /* We've now applied our changes, however they will be undone by the next
     * reset unless we also apply them to the LOCK bits in the User Page.  The
     * LOCK bits start at bit 48, corresponding to Sector 0 and end with bit 63,
     * corresponding to Sector 15.  A '1' means unlocked and a '0' means
     * locked.  See Table 9-3 in the SAMD20 datasheet for more details. */
 
    res = samd_modify_user_row(bank->target,
            set ? (uint64_t)0 : (uint64_t)UINT64_MAX,
            48 + first, 48 + last);
    if (res != ERROR_OK)
        LOG_WARNING("SAMD: protect settings were not made persistent!");
 
    res = ERROR_OK;
 
exit:
    samd_protect_check(bank);
 
    return res;
}
 
static int samd_erase(struct flash_bank *bank, unsigned int first,
        unsigned int last)
{
    int res;
    struct samd_info *chip = (struct samd_info *)bank->driver_priv;
 
    if (bank->target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
 
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (!chip->probed) {
        if (samd_probe(bank) != ERROR_OK)
            return ERROR_FLASH_BANK_NOT_PROBED;
    }
 
    /* For each sector to be erased */
    for (unsigned int s = first; s <= last; s++) {
        res = samd_erase_row(bank->target, bank->sectors[s].offset);
        if (res != ERROR_OK) {
            LOG_ERROR("SAMD: failed to erase sector %d at 0x%08" PRIx32, s, bank->sectors[s].offset);
            return res;
        }
    }
 
    return ERROR_OK;
}
 
 
static int samd_write(struct flash_bank *bank, const uint8_t *buffer,
        uint32_t offset, uint32_t count)
{
    int res;
    uint32_t nvm_ctrlb;
    uint32_t address;
    uint32_t pg_offset;
    uint32_t nb;
    uint32_t nw;
    struct samd_info *chip = (struct samd_info *)bank->driver_priv;
    uint8_t *pb = NULL;
    bool manual_wp;
 
    if (bank->target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (!chip->probed) {
        if (samd_probe(bank) != ERROR_OK)
            return ERROR_FLASH_BANK_NOT_PROBED;
    }
 
    /* Check if we need to do manual page write commands */
    res = target_read_u32(bank->target, SAMD_NVMCTRL + SAMD_NVMCTRL_CTRLB, &nvm_ctrlb);
 
    if (res != ERROR_OK)
        return res;
 
    if (nvm_ctrlb & SAMD_NVM_CTRLB_MANW)
        manual_wp = true;
    else
        manual_wp = false;
 
    res = samd_issue_nvmctrl_command(bank->target, SAMD_NVM_CMD_PBC);
    if (res != ERROR_OK) {
        LOG_ERROR("%s: %d", __func__, __LINE__);
        return res;
    }
 
    while (count) {
        nb = chip->page_size - offset % chip->page_size;
        if (count < nb)
            nb = count;
 
        address = bank->base + offset;
        pg_offset = offset % chip->page_size;
 
        if (offset % 4 || (offset + nb) % 4) {
            /* Either start or end of write is not word aligned */
            if (!pb) {
                pb = malloc(chip->page_size);
                if (!pb)
                    return ERROR_FAIL;
            }
 
            /* Set temporary page buffer to 0xff and overwrite the relevant part */
            memset(pb, 0xff, chip->page_size);
            memcpy(pb + pg_offset, buffer, nb);
 
            /* Align start address to a word boundary */
            address -= offset % 4;
            pg_offset -= offset % 4;
            assert(pg_offset % 4 == 0);
 
            /* Extend length to whole words */
            nw = (nb + offset % 4 + 3) / 4;
            assert(pg_offset + 4 * nw <= chip->page_size);
 
            /* Now we have original data extended by 0xff bytes
             * to the nearest word boundary on both start and end */
            res = target_write_memory(bank->target, address, 4, nw, pb + pg_offset);
        } else {
            assert(nb % 4 == 0);
            nw = nb / 4;
            assert(pg_offset + 4 * nw <= chip->page_size);
 
            /* Word aligned data, use direct write from buffer */
            res = target_write_memory(bank->target, address, 4, nw, buffer);
        }
        if (res != ERROR_OK) {
            LOG_ERROR("%s: %d", __func__, __LINE__);
            goto free_pb;
        }
 
        /* Devices with errata 13134 have automatic page write enabled by default
         * For other devices issue a write page CMD to the NVM
         * If the page has not been written up to the last word
         * then issue CMD_WP always */
        if (manual_wp || pg_offset + 4 * nw < chip->page_size) {
            res = samd_issue_nvmctrl_command(bank->target, SAMD_NVM_CMD_WP);
        } else {
            /* Access through AHB is stalled while flash is being programmed */
            usleep(200);
 
            res = samd_check_error(bank->target);
        }
 
        if (res != ERROR_OK) {
            LOG_ERROR("%s: write failed at address 0x%08" PRIx32, __func__, address);
            goto free_pb;
        }
 
        /* We're done with the page contents */
        count -= nb;
        offset += nb;
        buffer += nb;
    }
 
free_pb:
    free(pb);
    return res;
}
 
FLASH_BANK_COMMAND_HANDLER(samd_flash_bank_command)
{
    if (bank->base != SAMD_FLASH) {
        LOG_ERROR("Address " TARGET_ADDR_FMT
                " invalid bank address (try 0x%08" PRIx32
                "[at91samd series] )",
                bank->base, SAMD_FLASH);
        return ERROR_FAIL;
    }
 
    struct samd_info *chip;
    chip = calloc(1, sizeof(*chip));
    if (!chip) {
        LOG_ERROR("No memory for flash bank chip info");
        return ERROR_FAIL;
    }
 
    chip->target = bank->target;
    chip->probed = false;
 
    bank->driver_priv = chip;
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(samd_handle_chip_erase_command)
{
    struct target *target = get_current_target(CMD_CTX);
    int res = ERROR_FAIL;
 
    if (target) {
        /* Enable access to the DSU by disabling the write protect bit */
        target_write_u32(target, SAMD_PAC1, (1<<1));
        /* intentionally without error checking - not accessible on secured chip */
 
        /* Tell the DSU to perform a full chip erase.  It takes about 240ms to
         * perform the erase. */
        res = target_write_u8(target, SAMD_DSU + SAMD_DSU_CTRL_EXT, (1<<4));
        if (res == ERROR_OK)
            command_print(CMD, "chip erase started");
        else
            command_print(CMD, "write to DSU CTRL failed");
    }
 
    return res;
}
 
COMMAND_HANDLER(samd_handle_set_security_command)
{
    int res = ERROR_OK;
    struct target *target = get_current_target(CMD_CTX);
 
    if (CMD_ARGC < 1 || (CMD_ARGC >= 1 && (strcmp(CMD_ARGV[0], "enable")))) {
        command_print(CMD, "supply the \"enable\" argument to proceed.");
        return ERROR_COMMAND_SYNTAX_ERROR;
    }
 
    if (target) {
        if (target->state != TARGET_HALTED) {
            LOG_ERROR("Target not halted");
            return ERROR_TARGET_NOT_HALTED;
        }
 
        res = samd_issue_nvmctrl_command(target, SAMD_NVM_CMD_SSB);
 
        /* Check (and clear) error conditions */
        if (res == ERROR_OK)
            command_print(CMD, "chip secured on next power-cycle");
        else
            command_print(CMD, "failed to secure chip");
    }
 
    return res;
}
 
COMMAND_HANDLER(samd_handle_eeprom_command)
{
    int res = ERROR_OK;
    struct target *target = get_current_target(CMD_CTX);
 
    if (target) {
        if (target->state != TARGET_HALTED) {
            LOG_ERROR("Target not halted");
            return ERROR_TARGET_NOT_HALTED;
        }
 
        if (CMD_ARGC >= 1) {
            int val = atoi(CMD_ARGV[0]);
            uint32_t code;
 
            if (val == 0)
                code = 7;
            else {
                /* Try to match size in bytes with corresponding size code */
                for (code = 0; code <= 6; code++) {
                    if (val == (2 << (13 - code)))
                        break;
                }
 
                if (code > 6) {
                    command_print(CMD, "Invalid EEPROM size.  Please see "
                            "datasheet for a list valid sizes.");
                    return ERROR_COMMAND_SYNTAX_ERROR;
                }
            }
 
            res = samd_modify_user_row(target, code, 4, 6);
        } else {
            uint16_t val;
            res = target_read_u16(target, SAMD_USER_ROW, &val);
            if (res == ERROR_OK) {
                uint32_t size = ((val >> 4) & 0x7); /* grab size code */
 
                if (size == 0x7)
                    command_print(CMD, "EEPROM is disabled");
                else {
                    /* Otherwise, 6 is 256B, 0 is 16KB */
                    command_print(CMD, "EEPROM size is %u bytes",
                            (2 << (13 - size)));
                }
            }
        }
    }
 
    return res;
}
 
COMMAND_HANDLER(samd_handle_nvmuserrow_command)
{
    int res = ERROR_OK;
    struct target *target = get_current_target(CMD_CTX);
 
    if (target) {
        if (CMD_ARGC > 2) {
            command_print(CMD, "Too much Arguments given.");
            return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
        if (CMD_ARGC > 0) {
            if (target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted.");
                return ERROR_TARGET_NOT_HALTED;
            }
 
            uint64_t mask;
            res = samd_get_reservedmask(target, &mask);
            if (res != ERROR_OK) {
                LOG_ERROR("Couldn't determine the mask for reserved bits.");
                return ERROR_FAIL;
            }
            mask &= NVMUSERROW_LOCKBIT_MASK;
 
            uint64_t value;
            COMMAND_PARSE_NUMBER(u64, CMD_ARGV[0], value);
 
            if (CMD_ARGC == 2) {
                uint64_t mask_temp;
                COMMAND_PARSE_NUMBER(u64, CMD_ARGV[1], mask_temp);
 
                mask &= mask_temp;
            }
            res = samd_modify_user_row_masked(target, value, mask);
            if (res != ERROR_OK)
                return res;
        }
 
        /* read register */
        uint64_t value;
        res = read_userrow(target, &value);
        if (res == ERROR_OK)
            command_print(CMD, "NVMUSERROW: 0x%016"PRIX64, value);
        else
            LOG_ERROR("NVMUSERROW could not be read.");
    }
    return res;
}
 
COMMAND_HANDLER(samd_handle_bootloader_command)
{
    int res = ERROR_OK;
    struct target *target = get_current_target(CMD_CTX);
 
    if (target) {
        if (target->state != TARGET_HALTED) {
            LOG_ERROR("Target not halted");
            return ERROR_TARGET_NOT_HALTED;
        }
 
        /* Retrieve the MCU's page size, in bytes. */
        uint32_t page_size;
        res = samd_get_flash_page_info(target, &page_size, NULL);
        if (res != ERROR_OK) {
            LOG_ERROR("Couldn't determine Flash page size");
            return res;
        }
 
        if (CMD_ARGC >= 1) {
            int val = atoi(CMD_ARGV[0]);
            uint32_t code;
 
            if (val == 0)
                code = 7;
            else {
                /* Try to match size in bytes with corresponding size code */
                for (code = 0; code <= 6; code++) {
                    if ((unsigned int)val == (2UL << (8UL - code)) * page_size)
                        break;
                }
 
                if (code > 6) {
                    command_print(CMD, "Invalid bootloader size.  Please "
                            "see datasheet for a list valid sizes.");
                    return ERROR_COMMAND_SYNTAX_ERROR;
                }
 
            }
 
            res = samd_modify_user_row(target, code, 0, 2);
        } else {
            uint16_t val;
            res = target_read_u16(target, SAMD_USER_ROW, &val);
            if (res == ERROR_OK) {
                uint32_t size = (val & 0x7); /* grab size code */
                uint32_t nb;
 
                if (size == 0x7)
                    nb = 0;
                else
                    nb = (2 << (8 - size)) * page_size;
 
                /* There are 4 pages per row */
                command_print(CMD, "Bootloader size is %" PRIu32 " bytes (%" PRIu32 " rows)",
                       nb, (uint32_t)(nb / (page_size * 4)));
            }
        }
    }
 
    return res;
}
 
 
 
COMMAND_HANDLER(samd_handle_reset_deassert)
{
    struct target *target = get_current_target(CMD_CTX);
    int retval = ERROR_OK;
    enum reset_types jtag_reset_config = jtag_get_reset_config();
 
    /* If the target has been unresponsive before, try to re-establish
     * communication now - CPU is held in reset by DSU, DAP is working */
    if (!target_was_examined(target))
        target_examine_one(target);
    target_poll(target);
 
    /* In case of sysresetreq, debug retains state set in cortex_m_assert_reset()
     * so we just release reset held by DSU
     *
     * n_RESET (srst) clears the DP, so reenable debug and set vector catch here
     *
     * After vectreset DSU release is not needed however makes no harm
     */
    if (target->reset_halt && (jtag_reset_config & RESET_HAS_SRST)) {
        retval = target_write_u32(target, DCB_DHCSR, DBGKEY | C_HALT | C_DEBUGEN);
        if (retval == ERROR_OK)
            retval = target_write_u32(target, DCB_DEMCR,
                TRCENA | VC_HARDERR | VC_BUSERR | VC_CORERESET);
        /* do not return on error here, releasing DSU reset is more important */
    }
 
    /* clear CPU Reset Phase Extension bit */
    int retval2 = target_write_u8(target, SAMD_DSU + SAMD_DSU_STATUSA, (1<<1));
    if (retval2 != ERROR_OK)
        return retval2;
 
    return retval;
}
 
static const struct command_registration at91samd_exec_command_handlers[] = {
    {
        .name = "dsu_reset_deassert",
        .handler = samd_handle_reset_deassert,
        .mode = COMMAND_EXEC,
        .help = "Deassert internal reset held by DSU.",
        .usage = "",
    },
    {
        .name = "chip-erase",
        .handler = samd_handle_chip_erase_command,
        .mode = COMMAND_EXEC,
        .help = "Erase the entire Flash by using the Chip-"
            "Erase feature in the Device Service Unit (DSU).",
        .usage = "",
    },
    {
        .name = "set-security",
        .handler = samd_handle_set_security_command,
        .mode = COMMAND_EXEC,
        .help = "Secure the chip's Flash by setting the Security Bit. "
            "This makes it impossible to read the Flash contents. "
            "The only way to undo this is to issue the chip-erase "
            "command.",
        .usage = "'enable'",
    },
    {
        .name = "eeprom",
        .usage = "[size_in_bytes]",
        .handler = samd_handle_eeprom_command,
        .mode = COMMAND_EXEC,
        .help = "Show or set the EEPROM size setting, stored in the User Row. "
            "Please see Table 20-3 of the SAMD20 datasheet for allowed values. "
            "Changes are stored immediately but take affect after the MCU is "
            "reset.",
    },
    {
        .name = "bootloader",
        .usage = "[size_in_bytes]",
        .handler = samd_handle_bootloader_command,
        .mode = COMMAND_EXEC,
        .help = "Show or set the bootloader size, stored in the User Row. "
            "Please see Table 20-2 of the SAMD20 datasheet for allowed values. "
            "Changes are stored immediately but take affect after the MCU is "
            "reset.",
    },
    {
        .name = "nvmuserrow",
        .usage = "[value] [mask]",
        .handler = samd_handle_nvmuserrow_command,
        .mode = COMMAND_EXEC,
        .help = "Show or set the nvmuserrow register. It is 64 bit wide "
            "and located at address 0x804000. Use the optional mask argument "
            "to prevent changes at positions where the bitvalue is zero. "
            "For security reasons the lock- and reserved-bits are masked out "
            "in background and therefore cannot be changed.",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration at91samd_command_handlers[] = {
    {
        .name = "at91samd",
        .mode = COMMAND_ANY,
        .help = "at91samd flash command group",
        .usage = "",
        .chain = at91samd_exec_command_handlers,
    },
    COMMAND_REGISTRATION_DONE
};
 
const struct flash_driver at91samd_flash = {
    .name = "at91samd",
    .commands = at91samd_command_handlers,
    .flash_bank_command = samd_flash_bank_command,
    .erase = samd_erase,
    .protect = samd_protect,
    .write = samd_write,
    .read = default_flash_read,
    .probe = samd_probe,
    .auto_probe = samd_probe,
    .erase_check = default_flash_blank_check,
    .protect_check = samd_protect_check,
    .free_driver_priv = default_flash_free_driver_priv,
};