[mirror_qemu.git] / hw / nvram / eeprom93xx.c

/*
 * QEMU EEPROM 93xx emulation
 *
 * Copyright (c) 2006-2007 Stefan Weil
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

/* Emulation for serial EEPROMs:
 * NMC93C06 256-Bit (16 x 16)
 * NMC93C46 1024-Bit (64 x 16)
 * NMC93C56 2028 Bit (128 x 16)
 * NMC93C66 4096 Bit (256 x 16)
 * Compatible devices include FM93C46 and others.
 *
 * Other drivers use these interface functions:
 * eeprom93xx_new   - add a new EEPROM (with 16, 64 or 256 words)
 * eeprom93xx_free  - destroy EEPROM
 * eeprom93xx_read  - read data from the EEPROM
 * eeprom93xx_write - write data to the EEPROM
 * eeprom93xx_data  - get EEPROM data array for external manipulation
 *
 * Todo list:
 * - No emulation of EEPROM timings.
 */

#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/nvram/eeprom93xx.h"
#include "migration/qemu-file-types.h"
#include "migration/vmstate.h"

/* Debug EEPROM emulation. */
//~ #define DEBUG_EEPROM

#ifdef DEBUG_EEPROM
#define logout(fmt, ...) fprintf(stderr, "EEPROM\t%-24s" fmt, __func__, ## __VA_ARGS__)
#else
#define logout(fmt, ...) ((void)0)
#endif

#define EEPROM_INSTANCE  0
#define OLD_EEPROM_VERSION 20061112
#define EEPROM_VERSION (OLD_EEPROM_VERSION + 1)

#if 0
typedef enum {
  eeprom_read  = 0x80,   /* read register xx */
  eeprom_write = 0x40,   /* write register xx */
  eeprom_erase = 0xc0,   /* erase register xx */
  eeprom_ewen  = 0x30,   /* erase / write enable */
  eeprom_ewds  = 0x00,   /* erase / write disable */
  eeprom_eral  = 0x20,   /* erase all registers */
  eeprom_wral  = 0x10,   /* write all registers */
  eeprom_amask = 0x0f,
  eeprom_imask = 0xf0
} eeprom_instruction_t;
#endif

#ifdef DEBUG_EEPROM
static const char *opstring[] = {
  "extended", "write", "read", "erase"
};
#endif

struct _eeprom_t {
    uint8_t  tick;
    uint8_t  address;
    uint8_t  command;
    uint8_t  writable;

    uint8_t eecs;
    uint8_t eesk;
    uint8_t eedo;

    uint8_t  addrbits;
    uint16_t size;
    uint16_t data;
    uint16_t contents[0];
};

/* Code for saving and restoring of EEPROM state. */

/* Restore an uint16_t from an uint8_t
   This is a Big hack, but it is how the old state did it.
 */

static int get_uint16_from_uint8(QEMUFile *f, void *pv, size_t size,
                                 const VMStateField *field)
{
    uint16_t *v = pv;
    *v = qemu_get_ubyte(f);
    return 0;
}

static int put_unused(QEMUFile *f, void *pv, size_t size,
                      const VMStateField *field, QJSON *vmdesc)
{
    fprintf(stderr, "uint16_from_uint8 is used only for backwards compatibility.\n");
    fprintf(stderr, "Never should be used to write a new state.\n");
    exit(0);

    return 0;
}

static const VMStateInfo vmstate_hack_uint16_from_uint8 = {
    .name = "uint16_from_uint8",
    .get  = get_uint16_from_uint8,
    .put  = put_unused,
};

#define VMSTATE_UINT16_HACK_TEST(_f, _s, _t)                           \
    VMSTATE_SINGLE_TEST(_f, _s, _t, 0, vmstate_hack_uint16_from_uint8, uint16_t)

static bool is_old_eeprom_version(void *opaque, int version_id)
{
    return version_id == OLD_EEPROM_VERSION;
}

static const VMStateDescription vmstate_eeprom = {
    .name = "eeprom",
    .version_id = EEPROM_VERSION,
    .minimum_version_id = OLD_EEPROM_VERSION,
    .fields = (VMStateField[]) {
        VMSTATE_UINT8(tick, eeprom_t),
        VMSTATE_UINT8(address, eeprom_t),
        VMSTATE_UINT8(command, eeprom_t),
        VMSTATE_UINT8(writable, eeprom_t),

        VMSTATE_UINT8(eecs, eeprom_t),
        VMSTATE_UINT8(eesk, eeprom_t),
        VMSTATE_UINT8(eedo, eeprom_t),

        VMSTATE_UINT8(addrbits, eeprom_t),
        VMSTATE_UINT16_HACK_TEST(size, eeprom_t, is_old_eeprom_version),
        VMSTATE_UNUSED_TEST(is_old_eeprom_version, 1),
        VMSTATE_UINT16_EQUAL_V(size, eeprom_t, EEPROM_VERSION, NULL),
        VMSTATE_UINT16(data, eeprom_t),
        VMSTATE_VARRAY_UINT16_UNSAFE(contents, eeprom_t, size, 0,
                                     vmstate_info_uint16, uint16_t),
        VMSTATE_END_OF_LIST()
    }
};

void eeprom93xx_write(eeprom_t *eeprom, int eecs, int eesk, int eedi)
{
    uint8_t tick = eeprom->tick;
    uint8_t eedo = eeprom->eedo;
    uint16_t address = eeprom->address;
    uint8_t command = eeprom->command;

    logout("CS=%u SK=%u DI=%u DO=%u, tick = %u\n",
           eecs, eesk, eedi, eedo, tick);

    if (!eeprom->eecs && eecs) {
        /* Start chip select cycle. */
        logout("Cycle start, waiting for 1st start bit (0)\n");
        tick = 0;
        command = 0x0;
        address = 0x0;
    } else if (eeprom->eecs && !eecs) {
        /* End chip select cycle. This triggers write / erase. */
        if (eeprom->writable) {
            uint8_t subcommand = address >> (eeprom->addrbits - 2);
            if (command == 0 && subcommand == 2) {
                /* Erase all. */
                for (address = 0; address < eeprom->size; address++) {
                    eeprom->contents[address] = 0xffff;
                }
            } else if (command == 3) {
                /* Erase word. */
                eeprom->contents[address] = 0xffff;
            } else if (tick >= 2 + 2 + eeprom->addrbits + 16) {
                if (command == 1) {
                    /* Write word. */
                    eeprom->contents[address] &= eeprom->data;
                } else if (command == 0 && subcommand == 1) {
                    /* Write all. */
                    for (address = 0; address < eeprom->size; address++) {
                        eeprom->contents[address] &= eeprom->data;
                    }
                }
            }
        }
        /* Output DO is tristate, read results in 1. */
        eedo = 1;
    } else if (eecs && !eeprom->eesk && eesk) {
        /* Raising edge of clock shifts data in. */
        if (tick == 0) {
            /* Wait for 1st start bit. */
            if (eedi == 0) {
                logout("Got correct 1st start bit, waiting for 2nd start bit (1)\n");
                tick++;
            } else {
                logout("wrong 1st start bit (is 1, should be 0)\n");
                tick = 2;
                //~ assert(!"wrong start bit");
            }
        } else if (tick == 1) {
            /* Wait for 2nd start bit. */
            if (eedi != 0) {
                logout("Got correct 2nd start bit, getting command + address\n");
                tick++;
            } else {
                logout("1st start bit is longer than needed\n");
            }
        } else if (tick < 2 + 2) {
            /* Got 2 start bits, transfer 2 opcode bits. */
            tick++;
            command <<= 1;
            if (eedi) {
                command += 1;
            }
        } else if (tick < 2 + 2 + eeprom->addrbits) {
            /* Got 2 start bits and 2 opcode bits, transfer all address bits. */
            tick++;
            address = ((address << 1) | eedi);
            if (tick == 2 + 2 + eeprom->addrbits) {
                logout("%s command, address = 0x%02x (value 0x%04x)\n",
                       opstring[command], address, eeprom->contents[address]);
                if (command == 2) {
                    eedo = 0;
                }
                address = address % eeprom->size;
                if (command == 0) {
                    /* Command code in upper 2 bits of address. */
                    switch (address >> (eeprom->addrbits - 2)) {
                    case 0:
                        logout("write disable command\n");
                        eeprom->writable = 0;
                        break;
                    case 1:
                        logout("write all command\n");
                        break;
                    case 2:
                        logout("erase all command\n");
                        break;
                    case 3:
                        logout("write enable command\n");
                        eeprom->writable = 1;
                        break;
                    }
                } else {
                    /* Read, write or erase word. */
                    eeprom->data = eeprom->contents[address];
                }
            }
        } else if (tick < 2 + 2 + eeprom->addrbits + 16) {
            /* Transfer 16 data bits. */
            tick++;
            if (command == 2) {
                /* Read word. */
                eedo = ((eeprom->data & 0x8000) != 0);
            }
            eeprom->data <<= 1;
            eeprom->data += eedi;
        } else {
            logout("additional unneeded tick, not processed\n");
        }
    }
    /* Save status of EEPROM. */
    eeprom->tick = tick;
    eeprom->eecs = eecs;
    eeprom->eesk = eesk;
    eeprom->eedo = eedo;
    eeprom->address = address;
    eeprom->command = command;
}

uint16_t eeprom93xx_read(eeprom_t *eeprom)
{
    /* Return status of pin DO (0 or 1). */
    logout("CS=%u DO=%u\n", eeprom->eecs, eeprom->eedo);
    return eeprom->eedo;
}

#if 0
void eeprom93xx_reset(eeprom_t *eeprom)
{
    /* prepare eeprom */
    logout("eeprom = 0x%p\n", eeprom);
    eeprom->tick = 0;
    eeprom->command = 0;
}
#endif

eeprom_t *eeprom93xx_new(DeviceState *dev, uint16_t nwords)
{
    /* Add a new EEPROM (with 16, 64 or 256 words). */
    eeprom_t *eeprom;
    uint8_t addrbits;

    switch (nwords) {
    case 16:
    case 64:
        addrbits = 6;
        break;
    case 128:
    case 256:
        addrbits = 8;
        break;
    default:
        assert(!"Unsupported EEPROM size, fallback to 64 words!");
        nwords = 64;
        addrbits = 6;
    }

    eeprom = (eeprom_t *)g_malloc0(sizeof(*eeprom) + nwords * 2);
    eeprom->size = nwords;
    eeprom->addrbits = addrbits;
    /* Output DO is tristate, read results in 1. */
    eeprom->eedo = 1;
    logout("eeprom = 0x%p, nwords = %u\n", eeprom, nwords);
    vmstate_register(dev, 0, &vmstate_eeprom, eeprom);
    return eeprom;
}

void eeprom93xx_free(DeviceState *dev, eeprom_t *eeprom)
{
    /* Destroy EEPROM. */
    logout("eeprom = 0x%p\n", eeprom);
    vmstate_unregister(dev, &vmstate_eeprom, eeprom);
    g_free(eeprom);
}

uint16_t *eeprom93xx_data(eeprom_t *eeprom)
{
    /* Get EEPROM data array. */
    return &eeprom->contents[0];
}

/* eof */
Commit	Line	Data
663e8e51 TS	1	/*
	2	* QEMU EEPROM 93xx emulation
	3	*
	4	* Copyright (c) 2006-2007 Stefan Weil
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
8167ee88	17	* along with this program; if not, see <http://www.gnu.org/licenses/>.
663e8e51 TS	18	*/
	19
	20	/* Emulation for serial EEPROMs:
	21	* NMC93C06 256-Bit (16 x 16)
	22	* NMC93C46 1024-Bit (64 x 16)
	23	* NMC93C56 2028 Bit (128 x 16)
	24	* NMC93C66 4096 Bit (256 x 16)
	25	* Compatible devices include FM93C46 and others.
	26	*
	27	* Other drivers use these interface functions:
	28	* eeprom93xx_new - add a new EEPROM (with 16, 64 or 256 words)
	29	* eeprom93xx_free - destroy EEPROM
	30	* eeprom93xx_read - read data from the EEPROM
	31	* eeprom93xx_write - write data to the EEPROM
	32	* eeprom93xx_data - get EEPROM data array for external manipulation
	33	*
	34	* Todo list:
	35	* - No emulation of EEPROM timings.
	36	*/
	37
0430891c	38	#include "qemu/osdep.h"
83c9f4ca	39	#include "hw/hw.h"
0d09e41a	40	#include "hw/nvram/eeprom93xx.h"
ca77ee28	41	#include "migration/qemu-file-types.h"
d6454270	42	#include "migration/vmstate.h"
663e8e51 TS	43
	44	/* Debug EEPROM emulation. */
	45	//~ #define DEBUG_EEPROM
	46
	47	#ifdef DEBUG_EEPROM
001faf32	48	#define logout(fmt, ...) fprintf(stderr, "EEPROM\t%-24s" fmt, __func__, ## __VA_ARGS__)
663e8e51	49	#else
001faf32	50	#define logout(fmt, ...) ((void)0)
663e8e51 TS	51	#endif
663e8e51 TS	52
7ab2589c AJ	53	#define EEPROM_INSTANCE 0
	54	#define OLD_EEPROM_VERSION 20061112
	55	#define EEPROM_VERSION (OLD_EEPROM_VERSION + 1)
663e8e51 TS	56
	57	#if 0
	58	typedef enum {
	59	eeprom_read = 0x80, /* read register xx */
	60	eeprom_write = 0x40, /* write register xx */
	61	eeprom_erase = 0xc0, /* erase register xx */
	62	eeprom_ewen = 0x30, /* erase / write enable */
	63	eeprom_ewds = 0x00, /* erase / write disable */
	64	eeprom_eral = 0x20, /* erase all registers */
	65	eeprom_wral = 0x10, /* write all registers */
	66	eeprom_amask = 0x0f,
	67	eeprom_imask = 0xf0
	68	} eeprom_instruction_t;
	69	#endif
	70
	71	#ifdef DEBUG_EEPROM
	72	static const char *opstring[] = {
	73	"extended", "write", "read", "erase"
	74	};
	75	#endif
	76
c227f099	77	struct _eeprom_t {
663e8e51 TS	78	uint8_t tick;
	79	uint8_t address;
	80	uint8_t command;
ebabb67a	81	uint8_t writable;
663e8e51 TS	82
	83	uint8_t eecs;
	84	uint8_t eesk;
	85	uint8_t eedo;
	86
	87	uint8_t addrbits;
7ab2589c	88	uint16_t size;
663e8e51 TS	89	uint16_t data;
	90	uint16_t contents[0];
	91	};
	92
	93	/* Code for saving and restoring of EEPROM state. */
	94
c4a0f2d3 JQ	95	/* Restore an uint16_t from an uint8_t
	96	This is a Big hack, but it is how the old state did it.
	97	*/
	98
2c21ee76	99	static int get_uint16_from_uint8(QEMUFile f, void pv, size_t size,
03fee66f	100	const VMStateField *field)
663e8e51	101	{
c4a0f2d3 JQ	102	uint16_t *v = pv;
	103	*v = qemu_get_ubyte(f);
	104	return 0;
	105	}
d4ae799c	106
03fee66f MAL	107	static int put_unused(QEMUFile f, void pv, size_t size,
03fee66f MAL	108	const VMStateField field, QJSON vmdesc)
c4a0f2d3 JQ	109	{
	110	fprintf(stderr, "uint16_from_uint8 is used only for backwards compatibility.\n");
	111	fprintf(stderr, "Never should be used to write a new state.\n");
	112	exit(0);
2c21ee76 JD	113
2c21ee76 JD	114	return 0;
c4a0f2d3	115	}
d4ae799c	116
d05ac8fa	117	static const VMStateInfo vmstate_hack_uint16_from_uint8 = {
c4a0f2d3 JQ	118	.name = "uint16_from_uint8",
	119	.get = get_uint16_from_uint8,
	120	.put = put_unused,
	121	};
d4ae799c	122
c4a0f2d3 JQ	123	#define VMSTATE_UINT16_HACK_TEST(_f, _s, _t) \
c4a0f2d3 JQ	124	VMSTATE_SINGLE_TEST(_f, _s, _t, 0, vmstate_hack_uint16_from_uint8, uint16_t)
663e8e51	125
c4a0f2d3	126	static bool is_old_eeprom_version(void *opaque, int version_id)
663e8e51	127	{
c4a0f2d3 JQ	128	return version_id == OLD_EEPROM_VERSION;
c4a0f2d3 JQ	129	}
d4ae799c	130
c4a0f2d3 JQ	131	static const VMStateDescription vmstate_eeprom = {
	132	.name = "eeprom",
	133	.version_id = EEPROM_VERSION,
	134	.minimum_version_id = OLD_EEPROM_VERSION,
d49805ae	135	.fields = (VMStateField[]) {
c4a0f2d3 JQ	136	VMSTATE_UINT8(tick, eeprom_t),
	137	VMSTATE_UINT8(address, eeprom_t),
	138	VMSTATE_UINT8(command, eeprom_t),
ebabb67a	139	VMSTATE_UINT8(writable, eeprom_t),
d4ae799c	140
c4a0f2d3 JQ	141	VMSTATE_UINT8(eecs, eeprom_t),
	142	VMSTATE_UINT8(eesk, eeprom_t),
	143	VMSTATE_UINT8(eedo, eeprom_t),
d4ae799c	144
c4a0f2d3 JQ	145	VMSTATE_UINT8(addrbits, eeprom_t),
	146	VMSTATE_UINT16_HACK_TEST(size, eeprom_t, is_old_eeprom_version),
	147	VMSTATE_UNUSED_TEST(is_old_eeprom_version, 1),
d2164ad3	148	VMSTATE_UINT16_EQUAL_V(size, eeprom_t, EEPROM_VERSION, NULL),
c4a0f2d3 JQ	149	VMSTATE_UINT16(data, eeprom_t),
	150	VMSTATE_VARRAY_UINT16_UNSAFE(contents, eeprom_t, size, 0,
	151	vmstate_info_uint16, uint16_t),
	152	VMSTATE_END_OF_LIST()
663e8e51	153	}
c4a0f2d3	154	};
663e8e51	155
c227f099	156	void eeprom93xx_write(eeprom_t *eeprom, int eecs, int eesk, int eedi)
663e8e51 TS	157	{
	158	uint8_t tick = eeprom->tick;
	159	uint8_t eedo = eeprom->eedo;
	160	uint16_t address = eeprom->address;
	161	uint8_t command = eeprom->command;
	162
	163	logout("CS=%u SK=%u DI=%u DO=%u, tick = %u\n",
	164	eecs, eesk, eedi, eedo, tick);
	165
6fedcaa1	166	if (!eeprom->eecs && eecs) {
663e8e51 TS	167	/* Start chip select cycle. */
	168	logout("Cycle start, waiting for 1st start bit (0)\n");
	169	tick = 0;
	170	command = 0x0;
	171	address = 0x0;
6fedcaa1	172	} else if (eeprom->eecs && !eecs) {
663e8e51	173	/* End chip select cycle. This triggers write / erase. */
ebabb67a	174	if (eeprom->writable) {
663e8e51 TS	175	uint8_t subcommand = address >> (eeprom->addrbits - 2);
	176	if (command == 0 && subcommand == 2) {
	177	/* Erase all. */
	178	for (address = 0; address < eeprom->size; address++) {
	179	eeprom->contents[address] = 0xffff;
	180	}
	181	} else if (command == 3) {
	182	/* Erase word. */
	183	eeprom->contents[address] = 0xffff;
	184	} else if (tick >= 2 + 2 + eeprom->addrbits + 16) {
	185	if (command == 1) {
	186	/* Write word. */
	187	eeprom->contents[address] &= eeprom->data;
	188	} else if (command == 0 && subcommand == 1) {
	189	/* Write all. */
	190	for (address = 0; address < eeprom->size; address++) {
	191	eeprom->contents[address] &= eeprom->data;
	192	}
	193	}
	194	}
	195	}
	196	/* Output DO is tristate, read results in 1. */
	197	eedo = 1;
6fedcaa1	198	} else if (eecs && !eeprom->eesk && eesk) {
663e8e51 TS	199	/* Raising edge of clock shifts data in. */
	200	if (tick == 0) {
	201	/* Wait for 1st start bit. */
	202	if (eedi == 0) {
	203	logout("Got correct 1st start bit, waiting for 2nd start bit (1)\n");
	204	tick++;
	205	} else {
	206	logout("wrong 1st start bit (is 1, should be 0)\n");
	207	tick = 2;
	208	//~ assert(!"wrong start bit");
	209	}
	210	} else if (tick == 1) {
	211	/* Wait for 2nd start bit. */
	212	if (eedi != 0) {
	213	logout("Got correct 2nd start bit, getting command + address\n");
	214	tick++;
	215	} else {
	216	logout("1st start bit is longer than needed\n");
	217	}
	218	} else if (tick < 2 + 2) {
	219	/* Got 2 start bits, transfer 2 opcode bits. */
	220	tick++;
	221	command <<= 1;
	222	if (eedi) {
	223	command += 1;
	224	}
	225	} else if (tick < 2 + 2 + eeprom->addrbits) {
	226	/* Got 2 start bits and 2 opcode bits, transfer all address bits. */
	227	tick++;
	228	address = ((address << 1) \| eedi);
	229	if (tick == 2 + 2 + eeprom->addrbits) {
	230	logout("%s command, address = 0x%02x (value 0x%04x)\n",
	231	opstring[command], address, eeprom->contents[address]);
	232	if (command == 2) {
	233	eedo = 0;
	234	}
	235	address = address % eeprom->size;
	236	if (command == 0) {
	237	/* Command code in upper 2 bits of address. */
	238	switch (address >> (eeprom->addrbits - 2)) {
6fedcaa1 AP	239	case 0:
	240	logout("write disable command\n");
	241	eeprom->writable = 0;
	242	break;
	243	case 1:
	244	logout("write all command\n");
	245	break;
	246	case 2:
	247	logout("erase all command\n");
	248	break;
	249	case 3:
	250	logout("write enable command\n");
	251	eeprom->writable = 1;
	252	break;
663e8e51 TS	253	}
	254	} else {
	255	/* Read, write or erase word. */
	256	eeprom->data = eeprom->contents[address];
	257	}
	258	}
	259	} else if (tick < 2 + 2 + eeprom->addrbits + 16) {
	260	/* Transfer 16 data bits. */
	261	tick++;
	262	if (command == 2) {
	263	/* Read word. */
	264	eedo = ((eeprom->data & 0x8000) != 0);
	265	}
	266	eeprom->data <<= 1;
	267	eeprom->data += eedi;
	268	} else {
	269	logout("additional unneeded tick, not processed\n");
	270	}
	271	}
	272	/* Save status of EEPROM. */
	273	eeprom->tick = tick;
	274	eeprom->eecs = eecs;
	275	eeprom->eesk = eesk;
	276	eeprom->eedo = eedo;
	277	eeprom->address = address;
	278	eeprom->command = command;
	279	}
	280
c227f099	281	uint16_t eeprom93xx_read(eeprom_t *eeprom)
663e8e51 TS	282	{
	283	/* Return status of pin DO (0 or 1). */
	284	logout("CS=%u DO=%u\n", eeprom->eecs, eeprom->eedo);
6fedcaa1	285	return eeprom->eedo;
663e8e51 TS	286	}
	287
	288	#if 0
	289	void eeprom93xx_reset(eeprom_t *eeprom)
	290	{
	291	/* prepare eeprom */
	292	logout("eeprom = 0x%p\n", eeprom);
	293	eeprom->tick = 0;
	294	eeprom->command = 0;
	295	}
	296	#endif
	297
5fce2b3e	298	eeprom_t eeprom93xx_new(DeviceState dev, uint16_t nwords)
663e8e51 TS	299	{
663e8e51 TS	300	/* Add a new EEPROM (with 16, 64 or 256 words). */
c227f099	301	eeprom_t *eeprom;
663e8e51 TS	302	uint8_t addrbits;
	303
	304	switch (nwords) {
6fedcaa1 AP	305	case 16:
	306	case 64:
	307	addrbits = 6;
	308	break;
	309	case 128:
	310	case 256:
	311	addrbits = 8;
	312	break;
	313	default:
	314	assert(!"Unsupported EEPROM size, fallback to 64 words!");
	315	nwords = 64;
	316	addrbits = 6;
663e8e51 TS	317	}
663e8e51 TS	318
7267c094	319	eeprom = (eeprom_t )g_malloc0(sizeof(eeprom) + nwords * 2);
663e8e51 TS	320	eeprom->size = nwords;
	321	eeprom->addrbits = addrbits;
	322	/* Output DO is tristate, read results in 1. */
	323	eeprom->eedo = 1;
	324	logout("eeprom = 0x%p, nwords = %u\n", eeprom, nwords);
5fce2b3e	325	vmstate_register(dev, 0, &vmstate_eeprom, eeprom);
663e8e51 TS	326	return eeprom;
	327	}
	328
5fce2b3e	329	void eeprom93xx_free(DeviceState dev, eeprom_t eeprom)
663e8e51 TS	330	{
	331	/* Destroy EEPROM. */
	332	logout("eeprom = 0x%p\n", eeprom);
5fce2b3e	333	vmstate_unregister(dev, &vmstate_eeprom, eeprom);
7267c094	334	g_free(eeprom);
663e8e51 TS	335	}
663e8e51 TS	336
c227f099	337	uint16_t eeprom93xx_data(eeprom_t eeprom)
663e8e51 TS	338	{
	339	/* Get EEPROM data array. */
	340	return &eeprom->contents[0];
	341	}
	342
	343	/* eof */