xref: /openbmc/qemu/hw/intc/riscv_imsic.c (revision 2f95279a) 
1 /*
2  * RISC-V IMSIC (Incoming Message Signaled Interrupt Controller)
3  *
4  * Copyright (c) 2021 Western Digital Corporation or its affiliates.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2 or later, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program.  If not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include "qemu/osdep.h"
20 #include "qapi/error.h"
21 #include "qemu/log.h"
22 #include "qemu/module.h"
23 #include "qemu/error-report.h"
24 #include "qemu/bswap.h"
25 #include "exec/address-spaces.h"
26 #include "hw/sysbus.h"
27 #include "hw/pci/msi.h"
28 #include "hw/boards.h"
29 #include "hw/qdev-properties.h"
30 #include "hw/intc/riscv_imsic.h"
31 #include "hw/irq.h"
32 #include "target/riscv/cpu.h"
33 #include "target/riscv/cpu_bits.h"
34 #include "sysemu/sysemu.h"
35 #include "sysemu/kvm.h"
36 #include "migration/vmstate.h"
37 
38 #define IMSIC_MMIO_PAGE_LE             0x00
39 #define IMSIC_MMIO_PAGE_BE             0x04
40 
41 #define IMSIC_MIN_ID                   ((IMSIC_EIPx_BITS * 2) - 1)
42 #define IMSIC_MAX_ID                   (IMSIC_TOPEI_IID_MASK)
43 
44 #define IMSIC_EISTATE_PENDING          (1U << 0)
45 #define IMSIC_EISTATE_ENABLED          (1U << 1)
46 #define IMSIC_EISTATE_ENPEND           (IMSIC_EISTATE_ENABLED | \
47                                         IMSIC_EISTATE_PENDING)
48 
49 static uint32_t riscv_imsic_topei(RISCVIMSICState *imsic, uint32_t page)
50 {
51     uint32_t i, max_irq, base;
52 
53     base = page * imsic->num_irqs;
54     max_irq = (imsic->eithreshold[page] &&
55                (imsic->eithreshold[page] <= imsic->num_irqs)) ?
56                imsic->eithreshold[page] : imsic->num_irqs;
57     for (i = 1; i < max_irq; i++) {
58         if ((imsic->eistate[base + i] & IMSIC_EISTATE_ENPEND) ==
59                 IMSIC_EISTATE_ENPEND) {
60             return (i << IMSIC_TOPEI_IID_SHIFT) | i;
61         }
62     }
63 
64     return 0;
65 }
66 
67 static void riscv_imsic_update(RISCVIMSICState *imsic, uint32_t page)
68 {
69     if (imsic->eidelivery[page] && riscv_imsic_topei(imsic, page)) {
70         qemu_irq_raise(imsic->external_irqs[page]);
71     } else {
72         qemu_irq_lower(imsic->external_irqs[page]);
73     }
74 }
75 
76 static int riscv_imsic_eidelivery_rmw(RISCVIMSICState *imsic, uint32_t page,
77                                       target_ulong *val,
78                                       target_ulong new_val,
79                                       target_ulong wr_mask)
80 {
81     target_ulong old_val = imsic->eidelivery[page];
82 
83     if (val) {
84         *val = old_val;
85     }
86 
87     wr_mask &= 0x1;
88     imsic->eidelivery[page] = (old_val & ~wr_mask) | (new_val & wr_mask);
89 
90     riscv_imsic_update(imsic, page);
91     return 0;
92 }
93 
94 static int riscv_imsic_eithreshold_rmw(RISCVIMSICState *imsic, uint32_t page,
95                                       target_ulong *val,
96                                       target_ulong new_val,
97                                       target_ulong wr_mask)
98 {
99     target_ulong old_val = imsic->eithreshold[page];
100 
101     if (val) {
102         *val = old_val;
103     }
104 
105     wr_mask &= IMSIC_MAX_ID;
106     imsic->eithreshold[page] = (old_val & ~wr_mask) | (new_val & wr_mask);
107 
108     riscv_imsic_update(imsic, page);
109     return 0;
110 }
111 
112 static int riscv_imsic_topei_rmw(RISCVIMSICState *imsic, uint32_t page,
113                                  target_ulong *val, target_ulong new_val,
114                                  target_ulong wr_mask)
115 {
116     uint32_t base, topei = riscv_imsic_topei(imsic, page);
117 
118     /* Read pending and enabled interrupt with highest priority */
119     if (val) {
120         *val = topei;
121     }
122 
123     /* Writes ignore value and clear top pending interrupt */
124     if (topei && wr_mask) {
125         topei >>= IMSIC_TOPEI_IID_SHIFT;
126         base = page * imsic->num_irqs;
127         if (topei) {
128             imsic->eistate[base + topei] &= ~IMSIC_EISTATE_PENDING;
129         }
130 
131         riscv_imsic_update(imsic, page);
132     }
133 
134     return 0;
135 }
136 
137 static int riscv_imsic_eix_rmw(RISCVIMSICState *imsic,
138                                uint32_t xlen, uint32_t page,
139                                uint32_t num, bool pend, target_ulong *val,
140                                target_ulong new_val, target_ulong wr_mask)
141 {
142     uint32_t i, base;
143     target_ulong mask;
144     uint32_t state = (pend) ? IMSIC_EISTATE_PENDING : IMSIC_EISTATE_ENABLED;
145 
146     if (xlen != 32) {
147         if (num & 0x1) {
148             return -EINVAL;
149         }
150         num >>= 1;
151     }
152     if (num >= (imsic->num_irqs / xlen)) {
153         return -EINVAL;
154     }
155 
156     base = (page * imsic->num_irqs) + (num * xlen);
157 
158     if (val) {
159         *val = 0;
160         for (i = 0; i < xlen; i++) {
161             mask = (target_ulong)1 << i;
162             *val |= (imsic->eistate[base + i] & state) ? mask : 0;
163         }
164     }
165 
166     for (i = 0; i < xlen; i++) {
167         /* Bit0 of eip0 and eie0 are read-only zero */
168         if (!num && !i) {
169             continue;
170         }
171 
172         mask = (target_ulong)1 << i;
173         if (wr_mask & mask) {
174             if (new_val & mask) {
175                 imsic->eistate[base + i] |= state;
176             } else {
177                 imsic->eistate[base + i] &= ~state;
178             }
179         }
180     }
181 
182     riscv_imsic_update(imsic, page);
183     return 0;
184 }
185 
186 static int riscv_imsic_rmw(void *arg, target_ulong reg, target_ulong *val,
187                            target_ulong new_val, target_ulong wr_mask)
188 {
189     RISCVIMSICState *imsic = arg;
190     uint32_t isel, priv, virt, vgein, xlen, page;
191 
192     priv = AIA_IREG_PRIV(reg);
193     virt = AIA_IREG_VIRT(reg);
194     isel = AIA_IREG_ISEL(reg);
195     vgein = AIA_IREG_VGEIN(reg);
196     xlen = AIA_IREG_XLEN(reg);
197 
198     if (imsic->mmode) {
199         if (priv == PRV_M && !virt) {
200             page = 0;
201         } else {
202             goto err;
203         }
204     } else {
205         if (priv == PRV_S) {
206             if (virt) {
207                 if (vgein && vgein < imsic->num_pages) {
208                     page = vgein;
209                 } else {
210                     goto err;
211                 }
212             } else {
213                 page = 0;
214             }
215         } else {
216             goto err;
217         }
218     }
219 
220     switch (isel) {
221     case ISELECT_IMSIC_EIDELIVERY:
222         return riscv_imsic_eidelivery_rmw(imsic, page, val,
223                                           new_val, wr_mask);
224     case ISELECT_IMSIC_EITHRESHOLD:
225         return riscv_imsic_eithreshold_rmw(imsic, page, val,
226                                            new_val, wr_mask);
227     case ISELECT_IMSIC_TOPEI:
228         return riscv_imsic_topei_rmw(imsic, page, val, new_val, wr_mask);
229     case ISELECT_IMSIC_EIP0 ... ISELECT_IMSIC_EIP63:
230         return riscv_imsic_eix_rmw(imsic, xlen, page,
231                                    isel - ISELECT_IMSIC_EIP0,
232                                    true, val, new_val, wr_mask);
233     case ISELECT_IMSIC_EIE0 ... ISELECT_IMSIC_EIE63:
234         return riscv_imsic_eix_rmw(imsic, xlen, page,
235                                    isel - ISELECT_IMSIC_EIE0,
236                                    false, val, new_val, wr_mask);
237     default:
238         break;
239     };
240 
241 err:
242     qemu_log_mask(LOG_GUEST_ERROR,
243                   "%s: Invalid register priv=%d virt=%d isel=%d vgein=%d\n",
244                   __func__, priv, virt, isel, vgein);
245     return -EINVAL;
246 }
247 
248 static uint64_t riscv_imsic_read(void *opaque, hwaddr addr, unsigned size)
249 {
250     RISCVIMSICState *imsic = opaque;
251 
252     /* Reads must be 4 byte words */
253     if ((addr & 0x3) != 0) {
254         goto err;
255     }
256 
257     /* Reads cannot be out of range */
258     if (addr > IMSIC_MMIO_SIZE(imsic->num_pages)) {
259         goto err;
260     }
261 
262     return 0;
263 
264 err:
265     qemu_log_mask(LOG_GUEST_ERROR,
266                   "%s: Invalid register read 0x%" HWADDR_PRIx "\n",
267                   __func__, addr);
268     return 0;
269 }
270 
271 static void riscv_imsic_write(void *opaque, hwaddr addr, uint64_t value,
272         unsigned size)
273 {
274     RISCVIMSICState *imsic = opaque;
275     uint32_t page;
276 
277     /* Writes must be 4 byte words */
278     if ((addr & 0x3) != 0) {
279         goto err;
280     }
281 
282     /* Writes cannot be out of range */
283     if (addr > IMSIC_MMIO_SIZE(imsic->num_pages)) {
284         goto err;
285     }
286 
287 #if defined(CONFIG_KVM)
288     if (kvm_irqchip_in_kernel()) {
289         struct kvm_msi msi;
290 
291         msi.address_lo = extract64(imsic->mmio.addr + addr, 0, 32);
292         msi.address_hi = extract64(imsic->mmio.addr + addr, 32, 32);
293         msi.data = le32_to_cpu(value);
294 
295         kvm_vm_ioctl(kvm_state, KVM_SIGNAL_MSI, &msi);
296 
297         return;
298     }
299 #endif
300 
301     /* Writes only supported for MSI little-endian registers */
302     page = addr >> IMSIC_MMIO_PAGE_SHIFT;
303     if ((addr & (IMSIC_MMIO_PAGE_SZ - 1)) == IMSIC_MMIO_PAGE_LE) {
304         if (value && (value < imsic->num_irqs)) {
305             imsic->eistate[(page * imsic->num_irqs) + value] |=
306                                                     IMSIC_EISTATE_PENDING;
307         }
308     }
309 
310     /* Update CPU external interrupt status */
311     riscv_imsic_update(imsic, page);
312 
313     return;
314 
315 err:
316     qemu_log_mask(LOG_GUEST_ERROR,
317                   "%s: Invalid register write 0x%" HWADDR_PRIx "\n",
318                   __func__, addr);
319 }
320 
321 static const MemoryRegionOps riscv_imsic_ops = {
322     .read = riscv_imsic_read,
323     .write = riscv_imsic_write,
324     .endianness = DEVICE_LITTLE_ENDIAN,
325     .valid = {
326         .min_access_size = 4,
327         .max_access_size = 4
328     }
329 };
330 
331 static void riscv_imsic_realize(DeviceState *dev, Error **errp)
332 {
333     RISCVIMSICState *imsic = RISCV_IMSIC(dev);
334     RISCVCPU *rcpu = RISCV_CPU(cpu_by_arch_id(imsic->hartid));
335     CPUState *cpu = cpu_by_arch_id(imsic->hartid);
336     CPURISCVState *env = cpu ? cpu_env(cpu) : NULL;
337 
338     if (!kvm_irqchip_in_kernel()) {
339         imsic->num_eistate = imsic->num_pages * imsic->num_irqs;
340         imsic->eidelivery = g_new0(uint32_t, imsic->num_pages);
341         imsic->eithreshold = g_new0(uint32_t, imsic->num_pages);
342         imsic->eistate = g_new0(uint32_t, imsic->num_eistate);
343     }
344 
345     memory_region_init_io(&imsic->mmio, OBJECT(dev), &riscv_imsic_ops,
346                           imsic, TYPE_RISCV_IMSIC,
347                           IMSIC_MMIO_SIZE(imsic->num_pages));
348     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &imsic->mmio);
349 
350     /* Claim the CPU interrupt to be triggered by this IMSIC */
351     if (riscv_cpu_claim_interrupts(rcpu,
352             (imsic->mmode) ? MIP_MEIP : MIP_SEIP) < 0) {
353         error_setg(errp, "%s already claimed",
354                    (imsic->mmode) ? "MEIP" : "SEIP");
355         return;
356     }
357 
358     /* Create output IRQ lines */
359     imsic->external_irqs = g_malloc(sizeof(qemu_irq) * imsic->num_pages);
360     qdev_init_gpio_out(dev, imsic->external_irqs, imsic->num_pages);
361 
362     /* Force select AIA feature and setup CSR read-modify-write callback */
363     if (env) {
364         if (!imsic->mmode) {
365             rcpu->cfg.ext_ssaia = true;
366             riscv_cpu_set_geilen(env, imsic->num_pages - 1);
367         } else {
368             rcpu->cfg.ext_smaia = true;
369         }
370         riscv_cpu_set_aia_ireg_rmw_fn(env, (imsic->mmode) ? PRV_M : PRV_S,
371                                       riscv_imsic_rmw, imsic);
372     }
373 
374     msi_nonbroken = true;
375 }
376 
377 static Property riscv_imsic_properties[] = {
378     DEFINE_PROP_BOOL("mmode", RISCVIMSICState, mmode, 0),
379     DEFINE_PROP_UINT32("hartid", RISCVIMSICState, hartid, 0),
380     DEFINE_PROP_UINT32("num-pages", RISCVIMSICState, num_pages, 0),
381     DEFINE_PROP_UINT32("num-irqs", RISCVIMSICState, num_irqs, 0),
382     DEFINE_PROP_END_OF_LIST(),
383 };
384 
385 static const VMStateDescription vmstate_riscv_imsic = {
386     .name = "riscv_imsic",
387     .version_id = 1,
388     .minimum_version_id = 1,
389     .fields = (const VMStateField[]) {
390             VMSTATE_VARRAY_UINT32(eidelivery, RISCVIMSICState,
391                                   num_pages, 0,
392                                   vmstate_info_uint32, uint32_t),
393             VMSTATE_VARRAY_UINT32(eithreshold, RISCVIMSICState,
394                                   num_pages, 0,
395                                   vmstate_info_uint32, uint32_t),
396             VMSTATE_VARRAY_UINT32(eistate, RISCVIMSICState,
397                                   num_eistate, 0,
398                                   vmstate_info_uint32, uint32_t),
399             VMSTATE_END_OF_LIST()
400         }
401 };
402 
403 static void riscv_imsic_class_init(ObjectClass *klass, void *data)
404 {
405     DeviceClass *dc = DEVICE_CLASS(klass);
406 
407     device_class_set_props(dc, riscv_imsic_properties);
408     dc->realize = riscv_imsic_realize;
409     dc->vmsd = &vmstate_riscv_imsic;
410 }
411 
412 static const TypeInfo riscv_imsic_info = {
413     .name          = TYPE_RISCV_IMSIC,
414     .parent        = TYPE_SYS_BUS_DEVICE,
415     .instance_size = sizeof(RISCVIMSICState),
416     .class_init    = riscv_imsic_class_init,
417 };
418 
419 static void riscv_imsic_register_types(void)
420 {
421     type_register_static(&riscv_imsic_info);
422 }
423 
424 type_init(riscv_imsic_register_types)
425 
426 /*
427  * Create IMSIC device.
428  */
429 DeviceState *riscv_imsic_create(hwaddr addr, uint32_t hartid, bool mmode,
430                                 uint32_t num_pages, uint32_t num_ids)
431 {
432     DeviceState *dev = qdev_new(TYPE_RISCV_IMSIC);
433     CPUState *cpu = cpu_by_arch_id(hartid);
434     uint32_t i;
435 
436     assert(!(addr & (IMSIC_MMIO_PAGE_SZ - 1)));
437     if (mmode) {
438         assert(num_pages == 1);
439     } else {
440         assert(num_pages >= 1 && num_pages <= (IRQ_LOCAL_GUEST_MAX + 1));
441     }
442     assert(IMSIC_MIN_ID <= num_ids);
443     assert(num_ids <= IMSIC_MAX_ID);
444     assert((num_ids & IMSIC_MIN_ID) == IMSIC_MIN_ID);
445 
446     qdev_prop_set_bit(dev, "mmode", mmode);
447     qdev_prop_set_uint32(dev, "hartid", hartid);
448     qdev_prop_set_uint32(dev, "num-pages", num_pages);
449     qdev_prop_set_uint32(dev, "num-irqs", num_ids + 1);
450 
451     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
452     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
453 
454     for (i = 0; i < num_pages; i++) {
455         if (!i) {
456             qdev_connect_gpio_out_named(dev, NULL, i,
457                                         qdev_get_gpio_in(DEVICE(cpu),
458                                             (mmode) ? IRQ_M_EXT : IRQ_S_EXT));
459         } else {
460             qdev_connect_gpio_out_named(dev, NULL, i,
461                                         qdev_get_gpio_in(DEVICE(cpu),
462                                             IRQ_LOCAL_MAX + i - 1));
463         }
464     }
465 
466     return dev;
467 }
468