--- /dev/null
+/*
+ * 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 "hw/hw.h"
+#include "hw/nvram/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 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)
+{
+ uint16_t *v = pv;
+ *v = qemu_get_ubyte(f);
+ return 0;
+}
+
+static void put_unused(QEMUFile *f, void *pv, size_t size)
+{
+ 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);
+}
+
+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),
+ 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 */
Code Review / kvmfornfv.git / blobdiff