xref: /openbmc/qemu/hw/ssi/xilinx_spi.c (revision 979a8902) 
1 /*
2  * QEMU model of the Xilinx SPI Controller
3  *
4  * Copyright (C) 2010 Edgar E. Iglesias.
5  * Copyright (C) 2012 Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
6  * Copyright (C) 2012 PetaLogix
7  *
8  * Permission is hereby granted, free of charge, to any person obtaining a copy
9  * of this software and associated documentation files (the "Software"), to deal
10  * in the Software without restriction, including without limitation the rights
11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12  * copies of the Software, and to permit persons to whom the Software is
13  * furnished to do so, subject to the following conditions:
14  *
15  * The above copyright notice and this permission notice shall be included in
16  * all copies or substantial portions of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24  * THE SOFTWARE.
25  */
26 
27 #include "qemu/osdep.h"
28 #include "hw/sysbus.h"
29 #include "migration/vmstate.h"
30 #include "qemu/log.h"
31 #include "qemu/module.h"
32 #include "qemu/fifo8.h"
33 
34 #include "hw/irq.h"
35 #include "hw/qdev-properties.h"
36 #include "hw/ssi/ssi.h"
37 
38 #ifdef XILINX_SPI_ERR_DEBUG
39 #define DB_PRINT(...) do { \
40     fprintf(stderr,  ": %s: ", __func__); \
41     fprintf(stderr, ## __VA_ARGS__); \
42     } while (0)
43 #else
44     #define DB_PRINT(...)
45 #endif
46 
47 #define R_DGIER     (0x1c / 4)
48 #define R_DGIER_IE  (1 << 31)
49 
50 #define R_IPISR     (0x20 / 4)
51 #define IRQ_DRR_NOT_EMPTY    (1 << (31 - 23))
52 #define IRQ_DRR_OVERRUN      (1 << (31 - 26))
53 #define IRQ_DRR_FULL         (1 << (31 - 27))
54 #define IRQ_TX_FF_HALF_EMPTY (1 << 6)
55 #define IRQ_DTR_UNDERRUN     (1 << 3)
56 #define IRQ_DTR_EMPTY        (1 << (31 - 29))
57 
58 #define R_IPIER     (0x28 / 4)
59 #define R_SRR       (0x40 / 4)
60 #define R_SPICR     (0x60 / 4)
61 #define R_SPICR_TXFF_RST     (1 << 5)
62 #define R_SPICR_RXFF_RST     (1 << 6)
63 #define R_SPICR_MTI          (1 << 8)
64 
65 #define R_SPISR     (0x64 / 4)
66 #define SR_TX_FULL    (1 << 3)
67 #define SR_TX_EMPTY   (1 << 2)
68 #define SR_RX_FULL    (1 << 1)
69 #define SR_RX_EMPTY   (1 << 0)
70 
71 #define R_SPIDTR    (0x68 / 4)
72 #define R_SPIDRR    (0x6C / 4)
73 #define R_SPISSR    (0x70 / 4)
74 #define R_TX_FF_OCY (0x74 / 4)
75 #define R_RX_FF_OCY (0x78 / 4)
76 #define R_MAX       (0x7C / 4)
77 
78 #define FIFO_CAPACITY 256
79 
80 #define TYPE_XILINX_SPI "xlnx.xps-spi"
81 #define XILINX_SPI(obj) OBJECT_CHECK(XilinxSPI, (obj), TYPE_XILINX_SPI)
82 
83 typedef struct XilinxSPI {
84     SysBusDevice parent_obj;
85 
86     MemoryRegion mmio;
87 
88     qemu_irq irq;
89     int irqline;
90 
91     uint8_t num_cs;
92     qemu_irq *cs_lines;
93 
94     SSIBus *spi;
95 
96     Fifo8 rx_fifo;
97     Fifo8 tx_fifo;
98 
99     uint32_t regs[R_MAX];
100 } XilinxSPI;
101 
102 static void txfifo_reset(XilinxSPI *s)
103 {
104     fifo8_reset(&s->tx_fifo);
105 
106     s->regs[R_SPISR] &= ~SR_TX_FULL;
107     s->regs[R_SPISR] |= SR_TX_EMPTY;
108 }
109 
110 static void rxfifo_reset(XilinxSPI *s)
111 {
112     fifo8_reset(&s->rx_fifo);
113 
114     s->regs[R_SPISR] |= SR_RX_EMPTY;
115     s->regs[R_SPISR] &= ~SR_RX_FULL;
116 }
117 
118 static void xlx_spi_update_cs(XilinxSPI *s)
119 {
120     int i;
121 
122     for (i = 0; i < s->num_cs; ++i) {
123         qemu_set_irq(s->cs_lines[i], !(~s->regs[R_SPISSR] & 1 << i));
124     }
125 }
126 
127 static void xlx_spi_update_irq(XilinxSPI *s)
128 {
129     uint32_t pending;
130 
131     s->regs[R_IPISR] |=
132             (!fifo8_is_empty(&s->rx_fifo) ? IRQ_DRR_NOT_EMPTY : 0) |
133             (fifo8_is_full(&s->rx_fifo) ? IRQ_DRR_FULL : 0);
134 
135     pending = s->regs[R_IPISR] & s->regs[R_IPIER];
136 
137     pending = pending && (s->regs[R_DGIER] & R_DGIER_IE);
138     pending = !!pending;
139 
140     /* This call lies right in the data paths so don't call the
141        irq chain unless things really changed.  */
142     if (pending != s->irqline) {
143         s->irqline = pending;
144         DB_PRINT("irq_change of state %d ISR:%x IER:%X\n",
145                     pending, s->regs[R_IPISR], s->regs[R_IPIER]);
146         qemu_set_irq(s->irq, pending);
147     }
148 
149 }
150 
151 static void xlx_spi_do_reset(XilinxSPI *s)
152 {
153     memset(s->regs, 0, sizeof s->regs);
154 
155     rxfifo_reset(s);
156     txfifo_reset(s);
157 
158     s->regs[R_SPISSR] = ~0;
159     xlx_spi_update_irq(s);
160     xlx_spi_update_cs(s);
161 }
162 
163 static void xlx_spi_reset(DeviceState *d)
164 {
165     xlx_spi_do_reset(XILINX_SPI(d));
166 }
167 
168 static inline int spi_master_enabled(XilinxSPI *s)
169 {
170     return !(s->regs[R_SPICR] & R_SPICR_MTI);
171 }
172 
173 static void spi_flush_txfifo(XilinxSPI *s)
174 {
175     uint32_t tx;
176     uint32_t rx;
177 
178     while (!fifo8_is_empty(&s->tx_fifo)) {
179         tx = (uint32_t)fifo8_pop(&s->tx_fifo);
180         DB_PRINT("data tx:%x\n", tx);
181         rx = ssi_transfer(s->spi, tx);
182         DB_PRINT("data rx:%x\n", rx);
183         if (fifo8_is_full(&s->rx_fifo)) {
184             s->regs[R_IPISR] |= IRQ_DRR_OVERRUN;
185         } else {
186             fifo8_push(&s->rx_fifo, (uint8_t)rx);
187             if (fifo8_is_full(&s->rx_fifo)) {
188                 s->regs[R_SPISR] |= SR_RX_FULL;
189                 s->regs[R_IPISR] |= IRQ_DRR_FULL;
190             }
191         }
192 
193         s->regs[R_SPISR] &= ~SR_RX_EMPTY;
194         s->regs[R_SPISR] &= ~SR_TX_FULL;
195         s->regs[R_SPISR] |= SR_TX_EMPTY;
196 
197         s->regs[R_IPISR] |= IRQ_DTR_EMPTY;
198         s->regs[R_IPISR] |= IRQ_DRR_NOT_EMPTY;
199     }
200 
201 }
202 
203 static uint64_t
204 spi_read(void *opaque, hwaddr addr, unsigned int size)
205 {
206     XilinxSPI *s = opaque;
207     uint32_t r = 0;
208 
209     addr >>= 2;
210     switch (addr) {
211     case R_SPIDRR:
212         if (fifo8_is_empty(&s->rx_fifo)) {
213             DB_PRINT("Read from empty FIFO!\n");
214             return 0xdeadbeef;
215         }
216 
217         s->regs[R_SPISR] &= ~SR_RX_FULL;
218         r = fifo8_pop(&s->rx_fifo);
219         if (fifo8_is_empty(&s->rx_fifo)) {
220             s->regs[R_SPISR] |= SR_RX_EMPTY;
221         }
222         break;
223 
224     case R_SPISR:
225         r = s->regs[addr];
226         break;
227 
228     default:
229         if (addr < ARRAY_SIZE(s->regs)) {
230             r = s->regs[addr];
231         }
232         break;
233 
234     }
235     DB_PRINT("addr=" TARGET_FMT_plx " = %x\n", addr * 4, r);
236     xlx_spi_update_irq(s);
237     return r;
238 }
239 
240 static void
241 spi_write(void *opaque, hwaddr addr,
242             uint64_t val64, unsigned int size)
243 {
244     XilinxSPI *s = opaque;
245     uint32_t value = val64;
246 
247     DB_PRINT("addr=" TARGET_FMT_plx " = %x\n", addr, value);
248     addr >>= 2;
249     switch (addr) {
250     case R_SRR:
251         if (value != 0xa) {
252             DB_PRINT("Invalid write to SRR %x\n", value);
253         } else {
254             xlx_spi_do_reset(s);
255         }
256         break;
257 
258     case R_SPIDTR:
259         s->regs[R_SPISR] &= ~SR_TX_EMPTY;
260         fifo8_push(&s->tx_fifo, (uint8_t)value);
261         if (fifo8_is_full(&s->tx_fifo)) {
262             s->regs[R_SPISR] |= SR_TX_FULL;
263         }
264         if (!spi_master_enabled(s)) {
265             goto done;
266         } else {
267             DB_PRINT("DTR and master enabled\n");
268         }
269         spi_flush_txfifo(s);
270         break;
271 
272     case R_SPISR:
273         DB_PRINT("Invalid write to SPISR %x\n", value);
274         break;
275 
276     case R_IPISR:
277         /* Toggle the bits.  */
278         s->regs[addr] ^= value;
279         break;
280 
281     /* Slave Select Register.  */
282     case R_SPISSR:
283         s->regs[addr] = value;
284         xlx_spi_update_cs(s);
285         break;
286 
287     case R_SPICR:
288         /* FIXME: reset irq and sr state to empty queues.  */
289         if (value & R_SPICR_RXFF_RST) {
290             rxfifo_reset(s);
291         }
292 
293         if (value & R_SPICR_TXFF_RST) {
294             txfifo_reset(s);
295         }
296         value &= ~(R_SPICR_RXFF_RST | R_SPICR_TXFF_RST);
297         s->regs[addr] = value;
298 
299         if (!(value & R_SPICR_MTI)) {
300             spi_flush_txfifo(s);
301         }
302         break;
303 
304     default:
305         if (addr < ARRAY_SIZE(s->regs)) {
306             s->regs[addr] = value;
307         }
308         break;
309     }
310 
311 done:
312     xlx_spi_update_irq(s);
313 }
314 
315 static const MemoryRegionOps spi_ops = {
316     .read = spi_read,
317     .write = spi_write,
318     .endianness = DEVICE_NATIVE_ENDIAN,
319     .valid = {
320         .min_access_size = 4,
321         .max_access_size = 4
322     }
323 };
324 
325 static void xilinx_spi_realize(DeviceState *dev, Error **errp)
326 {
327     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
328     XilinxSPI *s = XILINX_SPI(dev);
329     int i;
330 
331     DB_PRINT("\n");
332 
333     s->spi = ssi_create_bus(dev, "spi");
334 
335     sysbus_init_irq(sbd, &s->irq);
336     s->cs_lines = g_new0(qemu_irq, s->num_cs);
337     ssi_auto_connect_slaves(dev, s->cs_lines, s->spi);
338     for (i = 0; i < s->num_cs; ++i) {
339         sysbus_init_irq(sbd, &s->cs_lines[i]);
340     }
341 
342     memory_region_init_io(&s->mmio, OBJECT(s), &spi_ops, s,
343                           "xilinx-spi", R_MAX * 4);
344     sysbus_init_mmio(sbd, &s->mmio);
345 
346     s->irqline = -1;
347 
348     fifo8_create(&s->tx_fifo, FIFO_CAPACITY);
349     fifo8_create(&s->rx_fifo, FIFO_CAPACITY);
350 }
351 
352 static const VMStateDescription vmstate_xilinx_spi = {
353     .name = "xilinx_spi",
354     .version_id = 1,
355     .minimum_version_id = 1,
356     .fields = (VMStateField[]) {
357         VMSTATE_FIFO8(tx_fifo, XilinxSPI),
358         VMSTATE_FIFO8(rx_fifo, XilinxSPI),
359         VMSTATE_UINT32_ARRAY(regs, XilinxSPI, R_MAX),
360         VMSTATE_END_OF_LIST()
361     }
362 };
363 
364 static Property xilinx_spi_properties[] = {
365     DEFINE_PROP_UINT8("num-ss-bits", XilinxSPI, num_cs, 1),
366     DEFINE_PROP_END_OF_LIST(),
367 };
368 
369 static void xilinx_spi_class_init(ObjectClass *klass, void *data)
370 {
371     DeviceClass *dc = DEVICE_CLASS(klass);
372 
373     dc->realize = xilinx_spi_realize;
374     dc->reset = xlx_spi_reset;
375     device_class_set_props(dc, xilinx_spi_properties);
376     dc->vmsd = &vmstate_xilinx_spi;
377 }
378 
379 static const TypeInfo xilinx_spi_info = {
380     .name           = TYPE_XILINX_SPI,
381     .parent         = TYPE_SYS_BUS_DEVICE,
382     .instance_size  = sizeof(XilinxSPI),
383     .class_init     = xilinx_spi_class_init,
384 };
385 
386 static void xilinx_spi_register_types(void)
387 {
388     type_register_static(&xilinx_spi_info);
389 }
390 
391 type_init(xilinx_spi_register_types)
392