xref: /openbmc/qemu/hw/block/swim.c (revision 2a886794)
1 /*
2  * QEMU Macintosh floppy disk controller emulator (SWIM)
3  *
4  * Copyright (c) 2014-2018 Laurent Vivier <laurent@vivier.eu>
5  *
6  * This work is licensed under the terms of the GNU GPL, version 2.  See
7  * the COPYING file in the top-level directory.
8  *
9  * Only the basic support: it allows to switch from IWM (Integrated WOZ
10  * Machine) mode to the SWIM mode and makes the linux driver happy.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qemu/main-loop.h"
15 #include "qapi/error.h"
16 #include "sysemu/block-backend.h"
17 #include "hw/sysbus.h"
18 #include "migration/vmstate.h"
19 #include "hw/block/block.h"
20 #include "hw/block/swim.h"
21 #include "hw/qdev-properties.h"
22 
23 /* IWM registers */
24 
25 #define IWM_PH0L                0
26 #define IWM_PH0H                1
27 #define IWM_PH1L                2
28 #define IWM_PH1H                3
29 #define IWM_PH2L                4
30 #define IWM_PH2H                5
31 #define IWM_PH3L                6
32 #define IWM_PH3H                7
33 #define IWM_MTROFF              8
34 #define IWM_MTRON               9
35 #define IWM_INTDRIVE            10
36 #define IWM_EXTDRIVE            11
37 #define IWM_Q6L                 12
38 #define IWM_Q6H                 13
39 #define IWM_Q7L                 14
40 #define IWM_Q7H                 15
41 
42 /* SWIM registers */
43 
44 #define SWIM_WRITE_DATA         0
45 #define SWIM_WRITE_MARK         1
46 #define SWIM_WRITE_CRC          2
47 #define SWIM_WRITE_PARAMETER    3
48 #define SWIM_WRITE_PHASE        4
49 #define SWIM_WRITE_SETUP        5
50 #define SWIM_WRITE_MODE0        6
51 #define SWIM_WRITE_MODE1        7
52 
53 #define SWIM_READ_DATA          8
54 #define SWIM_READ_MARK          9
55 #define SWIM_READ_ERROR         10
56 #define SWIM_READ_PARAMETER     11
57 #define SWIM_READ_PHASE         12
58 #define SWIM_READ_SETUP         13
59 #define SWIM_READ_STATUS        14
60 #define SWIM_READ_HANDSHAKE     15
61 
62 #define REG_SHIFT               9
63 
64 #define SWIM_MODE_IWM  0
65 #define SWIM_MODE_SWIM 1
66 
67 /* bits in phase register */
68 
69 #define SWIM_SEEK_NEGATIVE   0x074
70 #define SWIM_STEP            0x071
71 #define SWIM_MOTOR_ON        0x072
72 #define SWIM_MOTOR_OFF       0x076
73 #define SWIM_INDEX           0x073
74 #define SWIM_EJECT           0x077
75 #define SWIM_SETMFM          0x171
76 #define SWIM_SETGCR          0x175
77 #define SWIM_RELAX           0x033
78 #define SWIM_LSTRB           0x008
79 #define SWIM_CA_MASK         0x077
80 
81 /* Select values for swim_select and swim_readbit */
82 
83 #define SWIM_READ_DATA_0     0x074
84 #define SWIM_TWOMEG_DRIVE    0x075
85 #define SWIM_SINGLE_SIDED    0x076
86 #define SWIM_DRIVE_PRESENT   0x077
87 #define SWIM_DISK_IN         0x170
88 #define SWIM_WRITE_PROT      0x171
89 #define SWIM_TRACK_ZERO      0x172
90 #define SWIM_TACHO           0x173
91 #define SWIM_READ_DATA_1     0x174
92 #define SWIM_MFM_MODE        0x175
93 #define SWIM_SEEK_COMPLETE   0x176
94 #define SWIM_ONEMEG_MEDIA    0x177
95 
96 /* Bits in handshake register */
97 
98 #define SWIM_MARK_BYTE       0x01
99 #define SWIM_CRC_ZERO        0x02
100 #define SWIM_RDDATA          0x04
101 #define SWIM_SENSE           0x08
102 #define SWIM_MOTEN           0x10
103 #define SWIM_ERROR           0x20
104 #define SWIM_DAT2BYTE        0x40
105 #define SWIM_DAT1BYTE        0x80
106 
107 /* bits in setup register */
108 
109 #define SWIM_S_INV_WDATA     0x01
110 #define SWIM_S_3_5_SELECT    0x02
111 #define SWIM_S_GCR           0x04
112 #define SWIM_S_FCLK_DIV2     0x08
113 #define SWIM_S_ERROR_CORR    0x10
114 #define SWIM_S_IBM_DRIVE     0x20
115 #define SWIM_S_GCR_WRITE     0x40
116 #define SWIM_S_TIMEOUT       0x80
117 
118 /* bits in mode register */
119 
120 #define SWIM_CLFIFO          0x01
121 #define SWIM_ENBL1           0x02
122 #define SWIM_ENBL2           0x04
123 #define SWIM_ACTION          0x08
124 #define SWIM_WRITE_MODE      0x10
125 #define SWIM_HEDSEL          0x20
126 #define SWIM_MOTON           0x80
127 
128 static void fd_recalibrate(FDrive *drive)
129 {
130 }
131 
132 static void swim_change_cb(void *opaque, bool load, Error **errp)
133 {
134     FDrive *drive = opaque;
135 
136     if (!load) {
137         blk_set_perm(drive->blk, 0, BLK_PERM_ALL, &error_abort);
138     } else {
139         if (!blkconf_apply_backend_options(drive->conf,
140                                            blk_is_read_only(drive->blk), false,
141                                            errp)) {
142             return;
143         }
144     }
145 }
146 
147 static const BlockDevOps swim_block_ops = {
148     .change_media_cb = swim_change_cb,
149 };
150 
151 static Property swim_drive_properties[] = {
152     DEFINE_PROP_INT32("unit", SWIMDrive, unit, -1),
153     DEFINE_BLOCK_PROPERTIES(SWIMDrive, conf),
154     DEFINE_PROP_END_OF_LIST(),
155 };
156 
157 static void swim_drive_realize(DeviceState *qdev, Error **errp)
158 {
159     SWIMDrive *dev = SWIM_DRIVE(qdev);
160     SWIMBus *bus = SWIM_BUS(qdev->parent_bus);
161     FDrive *drive;
162     int ret;
163 
164     if (dev->unit == -1) {
165         for (dev->unit = 0; dev->unit < SWIM_MAX_FD; dev->unit++) {
166             drive = &bus->ctrl->drives[dev->unit];
167             if (!drive->blk) {
168                 break;
169             }
170         }
171     }
172 
173     if (dev->unit >= SWIM_MAX_FD) {
174         error_setg(errp, "Can't create floppy unit %d, bus supports "
175                    "only %d units", dev->unit, SWIM_MAX_FD);
176         return;
177     }
178 
179     drive = &bus->ctrl->drives[dev->unit];
180     if (drive->blk) {
181         error_setg(errp, "Floppy unit %d is in use", dev->unit);
182         return;
183     }
184 
185     if (!dev->conf.blk) {
186         /* Anonymous BlockBackend for an empty drive */
187         dev->conf.blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
188         ret = blk_attach_dev(dev->conf.blk, qdev);
189         assert(ret == 0);
190     }
191 
192     blkconf_blocksizes(&dev->conf);
193     if (dev->conf.logical_block_size != 512 ||
194         dev->conf.physical_block_size != 512)
195     {
196         error_setg(errp, "Physical and logical block size must "
197                    "be 512 for floppy");
198         return;
199     }
200 
201     /*
202      * rerror/werror aren't supported by fdc and therefore not even registered
203      * with qdev. So set the defaults manually before they are used in
204      * blkconf_apply_backend_options().
205      */
206     dev->conf.rerror = BLOCKDEV_ON_ERROR_AUTO;
207     dev->conf.werror = BLOCKDEV_ON_ERROR_AUTO;
208 
209     if (!blkconf_apply_backend_options(&dev->conf,
210                                        blk_is_read_only(dev->conf.blk),
211                                        false, errp)) {
212         return;
213     }
214 
215     /*
216      * 'enospc' is the default for -drive, 'report' is what blk_new() gives us
217      * for empty drives.
218      */
219     if (blk_get_on_error(dev->conf.blk, 0) != BLOCKDEV_ON_ERROR_ENOSPC &&
220         blk_get_on_error(dev->conf.blk, 0) != BLOCKDEV_ON_ERROR_REPORT) {
221         error_setg(errp, "fdc doesn't support drive option werror");
222         return;
223     }
224     if (blk_get_on_error(dev->conf.blk, 1) != BLOCKDEV_ON_ERROR_REPORT) {
225         error_setg(errp, "fdc doesn't support drive option rerror");
226         return;
227     }
228 
229     drive->conf = &dev->conf;
230     drive->blk = dev->conf.blk;
231     drive->swimctrl = bus->ctrl;
232 
233     blk_set_dev_ops(drive->blk, &swim_block_ops, drive);
234 }
235 
236 static void swim_drive_class_init(ObjectClass *klass, void *data)
237 {
238     DeviceClass *k = DEVICE_CLASS(klass);
239     k->realize = swim_drive_realize;
240     set_bit(DEVICE_CATEGORY_STORAGE, k->categories);
241     k->bus_type = TYPE_SWIM_BUS;
242     k->props = swim_drive_properties;
243     k->desc = "virtual SWIM drive";
244 }
245 
246 static const TypeInfo swim_drive_info = {
247     .name = TYPE_SWIM_DRIVE,
248     .parent = TYPE_DEVICE,
249     .instance_size = sizeof(SWIMDrive),
250     .class_init = swim_drive_class_init,
251 };
252 
253 static const TypeInfo swim_bus_info = {
254     .name = TYPE_SWIM_BUS,
255     .parent = TYPE_BUS,
256     .instance_size = sizeof(SWIMBus),
257 };
258 
259 static void iwmctrl_write(void *opaque, hwaddr reg, uint64_t value,
260                           unsigned size)
261 {
262     SWIMCtrl *swimctrl = opaque;
263 
264     reg >>= REG_SHIFT;
265 
266     swimctrl->regs[reg >> 1] = reg & 1;
267 
268     if (swimctrl->regs[IWM_Q6] &&
269         swimctrl->regs[IWM_Q7]) {
270         if (swimctrl->regs[IWM_MTR]) {
271             /* data register */
272             swimctrl->iwm_data = value;
273         } else {
274             /* mode register */
275             swimctrl->iwm_mode = value;
276             /* detect sequence to switch from IWM mode to SWIM mode */
277             switch (swimctrl->iwm_switch) {
278             case 0:
279                 if (value == 0x57) {
280                     swimctrl->iwm_switch++;
281                 }
282                 break;
283             case 1:
284                 if (value == 0x17) {
285                     swimctrl->iwm_switch++;
286                 }
287                 break;
288             case 2:
289                 if (value == 0x57) {
290                     swimctrl->iwm_switch++;
291                 }
292                 break;
293             case 3:
294                 if (value == 0x57) {
295                     swimctrl->mode = SWIM_MODE_SWIM;
296                     swimctrl->iwm_switch = 0;
297                 }
298                 break;
299             }
300         }
301     }
302 }
303 
304 static uint64_t iwmctrl_read(void *opaque, hwaddr reg, unsigned size)
305 {
306     SWIMCtrl *swimctrl = opaque;
307 
308     reg >>= REG_SHIFT;
309 
310     swimctrl->regs[reg >> 1] = reg & 1;
311 
312     return 0;
313 }
314 
315 static void swimctrl_write(void *opaque, hwaddr reg, uint64_t value,
316                            unsigned size)
317 {
318     SWIMCtrl *swimctrl = opaque;
319 
320     if (swimctrl->mode == SWIM_MODE_IWM) {
321         iwmctrl_write(opaque, reg, value, size);
322         return;
323     }
324 
325     reg >>= REG_SHIFT;
326 
327     switch (reg) {
328     case SWIM_WRITE_PHASE:
329         swimctrl->swim_phase = value;
330         break;
331     case SWIM_WRITE_MODE0:
332         swimctrl->swim_mode &= ~value;
333         break;
334     case SWIM_WRITE_MODE1:
335         swimctrl->swim_mode |= value;
336         break;
337     case SWIM_WRITE_DATA:
338     case SWIM_WRITE_MARK:
339     case SWIM_WRITE_CRC:
340     case SWIM_WRITE_PARAMETER:
341     case SWIM_WRITE_SETUP:
342         break;
343     }
344 }
345 
346 static uint64_t swimctrl_read(void *opaque, hwaddr reg, unsigned size)
347 {
348     SWIMCtrl *swimctrl = opaque;
349     uint32_t value = 0;
350 
351     if (swimctrl->mode == SWIM_MODE_IWM) {
352         return iwmctrl_read(opaque, reg, size);
353     }
354 
355     reg >>= REG_SHIFT;
356 
357     switch (reg) {
358     case SWIM_READ_PHASE:
359         value = swimctrl->swim_phase;
360         break;
361     case SWIM_READ_HANDSHAKE:
362         if (swimctrl->swim_phase == SWIM_DRIVE_PRESENT) {
363             /* always answer "no drive present" */
364             value = SWIM_SENSE;
365         }
366         break;
367     case SWIM_READ_DATA:
368     case SWIM_READ_MARK:
369     case SWIM_READ_ERROR:
370     case SWIM_READ_PARAMETER:
371     case SWIM_READ_SETUP:
372     case SWIM_READ_STATUS:
373         break;
374     }
375 
376     return value;
377 }
378 
379 static const MemoryRegionOps swimctrl_mem_ops = {
380     .write = swimctrl_write,
381     .read = swimctrl_read,
382     .endianness = DEVICE_NATIVE_ENDIAN,
383 };
384 
385 static void sysbus_swim_reset(DeviceState *d)
386 {
387     SWIM *sys = SWIM(d);
388     SWIMCtrl *ctrl = &sys->ctrl;
389     int i;
390 
391     ctrl->mode = 0;
392     ctrl->iwm_switch = 0;
393     for (i = 0; i < 8; i++) {
394         ctrl->regs[i] = 0;
395     }
396     ctrl->iwm_data = 0;
397     ctrl->iwm_mode = 0;
398     ctrl->swim_phase = 0;
399     ctrl->swim_mode = 0;
400     for (i = 0; i < SWIM_MAX_FD; i++) {
401         fd_recalibrate(&ctrl->drives[i]);
402     }
403 }
404 
405 static void sysbus_swim_init(Object *obj)
406 {
407     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
408     SWIM *sbs = SWIM(obj);
409     SWIMCtrl *swimctrl = &sbs->ctrl;
410 
411     memory_region_init_io(&swimctrl->iomem, obj, &swimctrl_mem_ops, swimctrl,
412                           "swim", 0x2000);
413     sysbus_init_mmio(sbd, &swimctrl->iomem);
414 }
415 
416 static void sysbus_swim_realize(DeviceState *dev, Error **errp)
417 {
418     SWIM *sys = SWIM(dev);
419     SWIMCtrl *swimctrl = &sys->ctrl;
420 
421     qbus_create_inplace(&swimctrl->bus, sizeof(SWIMBus), TYPE_SWIM_BUS, dev,
422                         NULL);
423     swimctrl->bus.ctrl = swimctrl;
424 }
425 
426 static const VMStateDescription vmstate_fdrive = {
427     .name = "fdrive",
428     .version_id = 1,
429     .minimum_version_id = 1,
430     .fields = (VMStateField[]) {
431         VMSTATE_END_OF_LIST()
432     },
433 };
434 
435 static const VMStateDescription vmstate_swim = {
436     .name = "swim",
437     .version_id = 1,
438     .minimum_version_id = 1,
439     .fields = (VMStateField[]) {
440         VMSTATE_INT32(mode, SWIMCtrl),
441         /* IWM mode */
442         VMSTATE_INT32(iwm_switch, SWIMCtrl),
443         VMSTATE_UINT16_ARRAY(regs, SWIMCtrl, 8),
444         VMSTATE_UINT8(iwm_data, SWIMCtrl),
445         VMSTATE_UINT8(iwm_mode, SWIMCtrl),
446         /* SWIM mode */
447         VMSTATE_UINT8(swim_phase, SWIMCtrl),
448         VMSTATE_UINT8(swim_mode, SWIMCtrl),
449         /* Drives */
450         VMSTATE_STRUCT_ARRAY(drives, SWIMCtrl, SWIM_MAX_FD, 1,
451                              vmstate_fdrive, FDrive),
452         VMSTATE_END_OF_LIST()
453     },
454 };
455 
456 static const VMStateDescription vmstate_sysbus_swim = {
457     .name = "SWIM",
458     .version_id = 1,
459     .fields = (VMStateField[]) {
460         VMSTATE_STRUCT(ctrl, SWIM, 0, vmstate_swim, SWIMCtrl),
461         VMSTATE_END_OF_LIST()
462     }
463 };
464 
465 static void sysbus_swim_class_init(ObjectClass *oc, void *data)
466 {
467     DeviceClass *dc = DEVICE_CLASS(oc);
468 
469     dc->realize = sysbus_swim_realize;
470     dc->reset = sysbus_swim_reset;
471     dc->vmsd = &vmstate_sysbus_swim;
472 }
473 
474 static const TypeInfo sysbus_swim_info = {
475     .name          = TYPE_SWIM,
476     .parent        = TYPE_SYS_BUS_DEVICE,
477     .instance_size = sizeof(SWIM),
478     .instance_init = sysbus_swim_init,
479     .class_init    = sysbus_swim_class_init,
480 };
481 
482 static void swim_register_types(void)
483 {
484     type_register_static(&sysbus_swim_info);
485     type_register_static(&swim_bus_info);
486     type_register_static(&swim_drive_info);
487 }
488 
489 type_init(swim_register_types)
490