[qemu.git] / hw / 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/* 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 "hw.h"
#include "eeprom93xx.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  writeable;

    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. */

static void eeprom_save(QEMUFile *f, void *opaque)
{
    /* Save EEPROM data. */
    unsigned address;
    eeprom_t *eeprom = (eeprom_t *)opaque;

    qemu_put_byte(f, eeprom->tick);
    qemu_put_byte(f, eeprom->address);
    qemu_put_byte(f, eeprom->command);
    qemu_put_byte(f, eeprom->writeable);

    qemu_put_byte(f, eeprom->eecs);
    qemu_put_byte(f, eeprom->eesk);
    qemu_put_byte(f, eeprom->eedo);

    qemu_put_byte(f, eeprom->addrbits);
    qemu_put_be16(f, eeprom->size);
    qemu_put_be16(f, eeprom->data);
    for (address = 0; address < eeprom->size; address++) {
        qemu_put_be16(f, eeprom->contents[address]);
    }
}

static int eeprom_load(QEMUFile *f, void *opaque, int version_id)
{
    /* Load EEPROM data from saved data if version and EEPROM size
       of data and current EEPROM are identical. */
    eeprom_t *eeprom = (eeprom_t *)opaque;
    int result = -EINVAL;
    if (version_id >= OLD_EEPROM_VERSION) {
        unsigned address;
        int size = eeprom->size;

        eeprom->tick = qemu_get_byte(f);
        eeprom->address = qemu_get_byte(f);
        eeprom->command = qemu_get_byte(f);
        eeprom->writeable = qemu_get_byte(f);

        eeprom->eecs = qemu_get_byte(f);
        eeprom->eesk = qemu_get_byte(f);
        eeprom->eedo = qemu_get_byte(f);

        eeprom->addrbits = qemu_get_byte(f);
        if (version_id == OLD_EEPROM_VERSION) {
            eeprom->size = qemu_get_byte(f);
            qemu_get_byte(f);
        } else {
            eeprom->size = qemu_get_be16(f);
        }

        if (eeprom->size == size) {
            eeprom->data = qemu_get_be16(f);
            for (address = 0; address < eeprom->size; address++) {
                eeprom->contents[address] = qemu_get_be16(f);
            }
            result = 0;
        }
    }
    return result;
}

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->writeable) {
            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->writeable = 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->writeable = 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(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 *)qemu_mallocz(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);
    register_savevm("eeprom", EEPROM_INSTANCE, EEPROM_VERSION,
                    eeprom_save, eeprom_load, eeprom);
    return eeprom;
}

void eeprom93xx_free(eeprom_t *eeprom)
{
    /* Destroy EEPROM. */
    logout("eeprom = 0x%p\n", eeprom);
    qemu_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
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
	21	/* Emulation for serial EEPROMs:
	22	* NMC93C06 256-Bit (16 x 16)
	23	* NMC93C46 1024-Bit (64 x 16)
	24	* NMC93C56 2028 Bit (128 x 16)
	25	* NMC93C66 4096 Bit (256 x 16)
	26	* Compatible devices include FM93C46 and others.
	27	*
	28	* Other drivers use these interface functions:
	29	* eeprom93xx_new - add a new EEPROM (with 16, 64 or 256 words)
	30	* eeprom93xx_free - destroy EEPROM
	31	* eeprom93xx_read - read data from the EEPROM
	32	* eeprom93xx_write - write data to the EEPROM
	33	* eeprom93xx_data - get EEPROM data array for external manipulation
	34	*
	35	* Todo list:
	36	* - No emulation of EEPROM timings.
	37	*/
	38
87ecb68b	39	#include "hw.h"
663e8e51 TS	40	#include "eeprom93xx.h"
	41
	42	/* Debug EEPROM emulation. */
	43	//~ #define DEBUG_EEPROM
	44
	45	#ifdef DEBUG_EEPROM
001faf32	46	#define logout(fmt, ...) fprintf(stderr, "EEPROM\t%-24s" fmt, __func__, ## __VA_ARGS__)
663e8e51	47	#else
001faf32	48	#define logout(fmt, ...) ((void)0)
663e8e51 TS	49	#endif
663e8e51 TS	50
7ab2589c AJ	51	#define EEPROM_INSTANCE 0
	52	#define OLD_EEPROM_VERSION 20061112
	53	#define EEPROM_VERSION (OLD_EEPROM_VERSION + 1)
663e8e51 TS	54
	55	#if 0
	56	typedef enum {
	57	eeprom_read = 0x80, /* read register xx */
	58	eeprom_write = 0x40, /* write register xx */
	59	eeprom_erase = 0xc0, /* erase register xx */
	60	eeprom_ewen = 0x30, /* erase / write enable */
	61	eeprom_ewds = 0x00, /* erase / write disable */
	62	eeprom_eral = 0x20, /* erase all registers */
	63	eeprom_wral = 0x10, /* write all registers */
	64	eeprom_amask = 0x0f,
	65	eeprom_imask = 0xf0
	66	} eeprom_instruction_t;
	67	#endif
	68
	69	#ifdef DEBUG_EEPROM
	70	static const char *opstring[] = {
	71	"extended", "write", "read", "erase"
	72	};
	73	#endif
	74
	75	struct _eeprom_t {
	76	uint8_t tick;
	77	uint8_t address;
	78	uint8_t command;
	79	uint8_t writeable;
	80
	81	uint8_t eecs;
	82	uint8_t eesk;
	83	uint8_t eedo;
	84
	85	uint8_t addrbits;
7ab2589c	86	uint16_t size;
663e8e51 TS	87	uint16_t data;
	88	uint16_t contents[0];
	89	};
	90
	91	/* Code for saving and restoring of EEPROM state. */
	92
	93	static void eeprom_save(QEMUFile f, void opaque)
	94	{
	95	/* Save EEPROM data. */
	96	unsigned address;
	97	eeprom_t eeprom = (eeprom_t )opaque;
d4ae799c AJ	98
	99	qemu_put_byte(f, eeprom->tick);
	100	qemu_put_byte(f, eeprom->address);
	101	qemu_put_byte(f, eeprom->command);
	102	qemu_put_byte(f, eeprom->writeable);
	103
	104	qemu_put_byte(f, eeprom->eecs);
	105	qemu_put_byte(f, eeprom->eesk);
	106	qemu_put_byte(f, eeprom->eedo);
	107
	108	qemu_put_byte(f, eeprom->addrbits);
7ab2589c	109	qemu_put_be16(f, eeprom->size);
663e8e51 TS	110	qemu_put_be16(f, eeprom->data);
	111	for (address = 0; address < eeprom->size; address++) {
	112	qemu_put_be16(f, eeprom->contents[address]);
	113	}
	114	}
	115
	116	static int eeprom_load(QEMUFile f, void opaque, int version_id)
	117	{
	118	/* Load EEPROM data from saved data if version and EEPROM size
	119	of data and current EEPROM are identical. */
	120	eeprom_t eeprom = (eeprom_t )opaque;
	121	int result = -EINVAL;
7ab2589c	122	if (version_id >= OLD_EEPROM_VERSION) {
663e8e51	123	unsigned address;
7ab2589c	124	int size = eeprom->size;
d4ae799c AJ	125
	126	eeprom->tick = qemu_get_byte(f);
	127	eeprom->address = qemu_get_byte(f);
	128	eeprom->command = qemu_get_byte(f);
	129	eeprom->writeable = qemu_get_byte(f);
	130
	131	eeprom->eecs = qemu_get_byte(f);
	132	eeprom->eesk = qemu_get_byte(f);
	133	eeprom->eedo = qemu_get_byte(f);
	134
	135	eeprom->addrbits = qemu_get_byte(f);
7ab2589c AJ	136	if (version_id == OLD_EEPROM_VERSION) {
	137	eeprom->size = qemu_get_byte(f);
	138	qemu_get_byte(f);
	139	} else {
	140	eeprom->size = qemu_get_be16(f);
	141	}
d4ae799c	142
663e8e51 TS	143	if (eeprom->size == size) {
	144	eeprom->data = qemu_get_be16(f);
	145	for (address = 0; address < eeprom->size; address++) {
	146	eeprom->contents[address] = qemu_get_be16(f);
	147	}
	148	result = 0;
	149	}
	150	}
	151	return result;
	152	}
	153
	154	void eeprom93xx_write(eeprom_t *eeprom, int eecs, int eesk, int eedi)
	155	{
	156	uint8_t tick = eeprom->tick;
	157	uint8_t eedo = eeprom->eedo;
	158	uint16_t address = eeprom->address;
	159	uint8_t command = eeprom->command;
	160
	161	logout("CS=%u SK=%u DI=%u DO=%u, tick = %u\n",
	162	eecs, eesk, eedi, eedo, tick);
	163
	164	if (! eeprom->eecs && eecs) {
	165	/* Start chip select cycle. */
	166	logout("Cycle start, waiting for 1st start bit (0)\n");
	167	tick = 0;
	168	command = 0x0;
	169	address = 0x0;
	170	} else if (eeprom->eecs && ! eecs) {
	171	/* End chip select cycle. This triggers write / erase. */
	172	if (eeprom->writeable) {
	173	uint8_t subcommand = address >> (eeprom->addrbits - 2);
	174	if (command == 0 && subcommand == 2) {
	175	/* Erase all. */
	176	for (address = 0; address < eeprom->size; address++) {
	177	eeprom->contents[address] = 0xffff;
	178	}
	179	} else if (command == 3) {
	180	/* Erase word. */
	181	eeprom->contents[address] = 0xffff;
	182	} else if (tick >= 2 + 2 + eeprom->addrbits + 16) {
	183	if (command == 1) {
	184	/* Write word. */
	185	eeprom->contents[address] &= eeprom->data;
	186	} else if (command == 0 && subcommand == 1) {
	187	/* Write all. */
	188	for (address = 0; address < eeprom->size; address++) {
	189	eeprom->contents[address] &= eeprom->data;
	190	}
	191	}
	192	}
	193	}
	194	/* Output DO is tristate, read results in 1. */
	195	eedo = 1;
	196	} else if (eecs && ! eeprom->eesk && eesk) {
	197	/* Raising edge of clock shifts data in. */
	198	if (tick == 0) {
	199	/* Wait for 1st start bit. */
	200	if (eedi == 0) {
	201	logout("Got correct 1st start bit, waiting for 2nd start bit (1)\n");
	202	tick++;
	203	} else {
	204	logout("wrong 1st start bit (is 1, should be 0)\n");
	205	tick = 2;
	206	//~ assert(!"wrong start bit");
207	}
208	} else if (tick == 1) {
209	/* Wait for 2nd start bit. */
210	if (eedi != 0) {
211	logout("Got correct 2nd start bit, getting command + address\n");
212	tick++;
213	} else {
214	logout("1st start bit is longer than needed\n");
215	}
216	} else if (tick < 2 + 2) {
217	/* Got 2 start bits, transfer 2 opcode bits. */
218	tick++;
219	command <<= 1;
220	if (eedi) {
221	command += 1;
222	}
223	} else if (tick < 2 + 2 + eeprom->addrbits) {
224	/* Got 2 start bits and 2 opcode bits, transfer all address bits. */
225	tick++;
226	address = ((address << 1) \| eedi);
227	if (tick == 2 + 2 + eeprom->addrbits) {
228	logout("%s command, address = 0x%02x (value 0x%04x)\n",
229	opstring[command], address, eeprom->contents[address]);
230	if (command == 2) {
231	eedo = 0;
232	}
233	address = address % eeprom->size;
234	if (command == 0) {
235	/* Command code in upper 2 bits of address. */
236	switch (address >> (eeprom->addrbits - 2)) {
237	case 0:
238	logout("write disable command\n");
239	eeprom->writeable = 0;
240	break;
241	case 1:
242	logout("write all command\n");
243	break;
244	case 2:
245	logout("erase all command\n");
246	break;
247	case 3:
248	logout("write enable command\n");
249	eeprom->writeable = 1;
250	break;
251	}
252	} else {
253	/* Read, write or erase word. */
254	eeprom->data = eeprom->contents[address];
255	}
256	}
257	} else if (tick < 2 + 2 + eeprom->addrbits + 16) {
258	/* Transfer 16 data bits. */
259	tick++;
260	if (command == 2) {
261	/* Read word. */
262	eedo = ((eeprom->data & 0x8000) != 0);
263	}
264	eeprom->data <<= 1;
265	eeprom->data += eedi;
266	} else {
267	logout("additional unneeded tick, not processed\n");
268	}
269	}
270	/* Save status of EEPROM. */
271	eeprom->tick = tick;
272	eeprom->eecs = eecs;
273	eeprom->eesk = eesk;
274	eeprom->eedo = eedo;
275	eeprom->address = address;
276	eeprom->command = command;
277	}
278
279	uint16_t eeprom93xx_read(eeprom_t *eeprom)
280	{
281	/* Return status of pin DO (0 or 1). */
282	logout("CS=%u DO=%u\n", eeprom->eecs, eeprom->eedo);
283	return (eeprom->eedo);
284	}
285
286	#if 0
287	void eeprom93xx_reset(eeprom_t *eeprom)
288	{
289	/* prepare eeprom */
290	logout("eeprom = 0x%p\n", eeprom);
291	eeprom->tick = 0;
292	eeprom->command = 0;
293	}
294	#endif
295
296	eeprom_t *eeprom93xx_new(uint16_t nwords)
297	{
298	/* Add a new EEPROM (with 16, 64 or 256 words). */
299	eeprom_t *eeprom;
300	uint8_t addrbits;
301
302	switch (nwords) {
303	case 16:
304	case 64:
305	addrbits = 6;
306	break;
307	case 128:
308	case 256:
309	addrbits = 8;
310	break;
311	default:
312	assert(!"Unsupported EEPROM size, fallback to 64 words!");
313	nwords = 64;
314	addrbits = 6;
315	}
316
317	eeprom = (eeprom_t )qemu_mallocz(sizeof(eeprom) + nwords * 2);
318	eeprom->size = nwords;
319	eeprom->addrbits = addrbits;
320	/* Output DO is tristate, read results in 1. */
321	eeprom->eedo = 1;
322	logout("eeprom = 0x%p, nwords = %u\n", eeprom, nwords);
7ab2589c	323	register_savevm("eeprom", EEPROM_INSTANCE, EEPROM_VERSION,
663e8e51 TS	324	eeprom_save, eeprom_load, eeprom);
	325	return eeprom;
	326	}
	327
	328	void eeprom93xx_free(eeprom_t *eeprom)
	329	{
	330	/* Destroy EEPROM. */
	331	logout("eeprom = 0x%p\n", eeprom);
	332	qemu_free(eeprom);
	333	}
	334
	335	uint16_t eeprom93xx_data(eeprom_t eeprom)
	336	{
	337	/* Get EEPROM data array. */
	338	return &eeprom->contents[0];
	339	}
	340
	341	/* eof */