hw/ppc/pnv_lpc.c

   1 /*
   2  * QEMU PowerPC PowerNV LPC controller
   3  *
   4  * Copyright (c) 2016, IBM Corporation.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "sysemu/sysemu.h"
  22 #include "target/ppc/cpu.h"
  23 #include "qapi/error.h"
  24 #include "qemu/log.h"
  25
  26 #include "hw/ppc/pnv.h"
  27 #include "hw/ppc/pnv_lpc.h"
  28 #include "hw/ppc/pnv_xscom.h"
  29 #include "hw/ppc/fdt.h"
  30
  31 #include <libfdt.h>
  32
  33 enum {
  34     ECCB_CTL    = 0,
  35     ECCB_RESET  = 1,
  36     ECCB_STAT   = 2,
  37     ECCB_DATA   = 3,
  38 };
  39
  40 /* OPB Master LS registers */
  41 #define OPB_MASTER_LS_IRQ_STAT  0x50
  42 #define   OPB_MASTER_IRQ_LPC            0x00000800
  43 #define OPB_MASTER_LS_IRQ_MASK  0x54
  44 #define OPB_MASTER_LS_IRQ_POL   0x58
  45 #define OPB_MASTER_LS_IRQ_INPUT 0x5c
  46
  47 /* LPC HC registers */
  48 #define LPC_HC_FW_SEG_IDSEL     0x24
  49 #define LPC_HC_FW_RD_ACC_SIZE   0x28
  50 #define   LPC_HC_FW_RD_1B               0x00000000
  51 #define   LPC_HC_FW_RD_2B               0x01000000
  52 #define   LPC_HC_FW_RD_4B               0x02000000
  53 #define   LPC_HC_FW_RD_16B              0x04000000
  54 #define   LPC_HC_FW_RD_128B             0x07000000
  55 #define LPC_HC_IRQSER_CTRL      0x30
  56 #define   LPC_HC_IRQSER_EN              0x80000000
  57 #define   LPC_HC_IRQSER_QMODE           0x40000000
  58 #define   LPC_HC_IRQSER_START_MASK      0x03000000
  59 #define   LPC_HC_IRQSER_START_4CLK      0x00000000
  60 #define   LPC_HC_IRQSER_START_6CLK      0x01000000
  61 #define   LPC_HC_IRQSER_START_8CLK      0x02000000
  62 #define LPC_HC_IRQMASK          0x34    /* same bit defs as LPC_HC_IRQSTAT */
  63 #define LPC_HC_IRQSTAT          0x38
  64 #define   LPC_HC_IRQ_SERIRQ0            0x80000000 /* all bits down to ... */
  65 #define   LPC_HC_IRQ_SERIRQ16           0x00008000 /* IRQ16=IOCHK#, IRQ2=SMI# */
  66 #define   LPC_HC_IRQ_SERIRQ_ALL         0xffff8000
  67 #define   LPC_HC_IRQ_LRESET             0x00000400
  68 #define   LPC_HC_IRQ_SYNC_ABNORM_ERR    0x00000080
  69 #define   LPC_HC_IRQ_SYNC_NORESP_ERR    0x00000040
  70 #define   LPC_HC_IRQ_SYNC_NORM_ERR      0x00000020
  71 #define   LPC_HC_IRQ_SYNC_TIMEOUT_ERR   0x00000010
  72 #define   LPC_HC_IRQ_SYNC_TARG_TAR_ERR  0x00000008
  73 #define   LPC_HC_IRQ_SYNC_BM_TAR_ERR    0x00000004
  74 #define   LPC_HC_IRQ_SYNC_BM0_REQ       0x00000002
  75 #define   LPC_HC_IRQ_SYNC_BM1_REQ       0x00000001
  76 #define LPC_HC_ERROR_ADDRESS    0x40
  77
  78 #define LPC_OPB_SIZE            0x100000000ull
  79
  80 #define ISA_IO_SIZE             0x00010000
  81 #define ISA_MEM_SIZE            0x10000000
  82 #define LPC_IO_OPB_ADDR         0xd0010000
  83 #define LPC_IO_OPB_SIZE         0x00010000
  84 #define LPC_MEM_OPB_ADDR        0xe0010000
  85 #define LPC_MEM_OPB_SIZE        0x10000000
  86 #define LPC_FW_OPB_ADDR         0xf0000000
  87 #define LPC_FW_OPB_SIZE         0x10000000
  88
  89 #define LPC_OPB_REGS_OPB_ADDR   0xc0010000
  90 #define LPC_OPB_REGS_OPB_SIZE   0x00002000
  91 #define LPC_HC_REGS_OPB_ADDR    0xc0012000
  92 #define LPC_HC_REGS_OPB_SIZE    0x00001000
  93
  94
  95 static int pnv_lpc_populate(PnvXScomInterface *dev, void *fdt, int xscom_offset)
  96 {
  97     const char compat[] = "ibm,power8-lpc\0ibm,lpc";
  98     char *name;
  99     int offset;
 100     uint32_t lpc_pcba = PNV_XSCOM_LPC_BASE;
 101     uint32_t reg[] = {
 102         cpu_to_be32(lpc_pcba),
 103         cpu_to_be32(PNV_XSCOM_LPC_SIZE)
 104     };
 105
 106     name = g_strdup_printf("isa@%x", lpc_pcba);
 107     offset = fdt_add_subnode(fdt, xscom_offset, name);
 108     _FDT(offset);
 109     g_free(name);
 110
 111     _FDT((fdt_setprop(fdt, offset, "reg", reg, sizeof(reg))));
 112     _FDT((fdt_setprop_cell(fdt, offset, "#address-cells", 2)));
 113     _FDT((fdt_setprop_cell(fdt, offset, "#size-cells", 1)));
 114     _FDT((fdt_setprop(fdt, offset, "compatible", compat, sizeof(compat))));
 115     return 0;
 116 }
 117
 118 /*
 119  * These read/write handlers of the OPB address space should be common
 120  * with the P9 LPC Controller which uses direct MMIOs.
 121  *
 122  * TODO: rework to use address_space_stq() and address_space_ldq()
 123  * instead.
 124  */
 125 static bool opb_read(PnvLpcController *lpc, uint32_t addr, uint8_t *data,
 126                      int sz)
 127 {
 128     bool success;
 129
 130     /* XXX Handle access size limits and FW read caching here */
 131     success = !address_space_rw(&lpc->opb_as, addr, MEMTXATTRS_UNSPECIFIED,
 132                                 data, sz, false);
 133
 134     return success;
 135 }
 136
 137 static bool opb_write(PnvLpcController *lpc, uint32_t addr, uint8_t *data,
 138                       int sz)
 139 {
 140     bool success;
 141
 142     /* XXX Handle access size limits here */
 143     success = !address_space_rw(&lpc->opb_as, addr, MEMTXATTRS_UNSPECIFIED,
 144                                 data, sz, true);
 145
 146     return success;
 147 }
 148
 149 #define ECCB_CTL_READ           (1ull << (63 - 15))
 150 #define ECCB_CTL_SZ_LSH         (63 - 7)
 151 #define ECCB_CTL_SZ_MASK        (0xfull << ECCB_CTL_SZ_LSH)
 152 #define ECCB_CTL_ADDR_MASK      0xffffffffu;
 153
 154 #define ECCB_STAT_OP_DONE       (1ull << (63 - 52))
 155 #define ECCB_STAT_OP_ERR        (1ull << (63 - 52))
 156 #define ECCB_STAT_RD_DATA_LSH   (63 - 37)
 157 #define ECCB_STAT_RD_DATA_MASK  (0xffffffff << ECCB_STAT_RD_DATA_LSH)
 158
 159 static void pnv_lpc_do_eccb(PnvLpcController *lpc, uint64_t cmd)
 160 {
 161     /* XXX Check for magic bits at the top, addr size etc... */
 162     unsigned int sz = (cmd & ECCB_CTL_SZ_MASK) >> ECCB_CTL_SZ_LSH;
 163     uint32_t opb_addr = cmd & ECCB_CTL_ADDR_MASK;
 164     uint8_t data[4];
 165     bool success;
 166
 167     if (cmd & ECCB_CTL_READ) {
 168         success = opb_read(lpc, opb_addr, data, sz);
 169         if (success) {
 170             lpc->eccb_stat_reg = ECCB_STAT_OP_DONE |
 171                     (((uint64_t)data[0]) << 24 |
 172                      ((uint64_t)data[1]) << 16 |
 173                      ((uint64_t)data[2]) <<  8 |
 174                      ((uint64_t)data[3])) << ECCB_STAT_RD_DATA_LSH;
 175         } else {
 176             lpc->eccb_stat_reg = ECCB_STAT_OP_DONE |
 177                     (0xffffffffull << ECCB_STAT_RD_DATA_LSH);
 178         }
 179     } else {
 180         data[0] = lpc->eccb_data_reg >> 24;
 181         data[1] = lpc->eccb_data_reg >> 16;
 182         data[2] = lpc->eccb_data_reg >>  8;
 183         data[3] = lpc->eccb_data_reg;
 184
 185         success = opb_write(lpc, opb_addr, data, sz);
 186         lpc->eccb_stat_reg = ECCB_STAT_OP_DONE;
 187     }
 188     /* XXX Which error bit (if any) to signal OPB error ? */
 189 }
 190
 191 static uint64_t pnv_lpc_xscom_read(void *opaque, hwaddr addr, unsigned size)
 192 {
 193     PnvLpcController *lpc = PNV_LPC(opaque);
 194     uint32_t offset = addr >> 3;
 195     uint64_t val = 0;
 196
 197     switch (offset & 3) {
 198     case ECCB_CTL:
 199     case ECCB_RESET:
 200         val = 0;
 201         break;
 202     case ECCB_STAT:
 203         val = lpc->eccb_stat_reg;
 204         lpc->eccb_stat_reg = 0;
 205         break;
 206     case ECCB_DATA:
 207         val = ((uint64_t)lpc->eccb_data_reg) << 32;
 208         break;
 209     }
 210     return val;
 211 }
 212
 213 static void pnv_lpc_xscom_write(void *opaque, hwaddr addr,
 214                                 uint64_t val, unsigned size)
 215 {
 216     PnvLpcController *lpc = PNV_LPC(opaque);
 217     uint32_t offset = addr >> 3;
 218
 219     switch (offset & 3) {
 220     case ECCB_CTL:
 221         pnv_lpc_do_eccb(lpc, val);
 222         break;
 223     case ECCB_RESET:
 224         /*  XXXX  */
 225         break;
 226     case ECCB_STAT:
 227         break;
 228     case ECCB_DATA:
 229         lpc->eccb_data_reg = val >> 32;
 230         break;
 231     }
 232 }
 233
 234 static const MemoryRegionOps pnv_lpc_xscom_ops = {
 235     .read = pnv_lpc_xscom_read,
 236     .write = pnv_lpc_xscom_write,
 237     .valid.min_access_size = 8,
 238     .valid.max_access_size = 8,
 239     .impl.min_access_size = 8,
 240     .impl.max_access_size = 8,
 241     .endianness = DEVICE_BIG_ENDIAN,
 242 };
 243
 244 static void pnv_lpc_eval_irqs(PnvLpcController *lpc)
 245 {
 246     bool lpc_to_opb_irq = false;
 247
 248     /* Update LPC controller to OPB line */
 249     if (lpc->lpc_hc_irqser_ctrl & LPC_HC_IRQSER_EN) {
 250         uint32_t irqs;
 251
 252         irqs = lpc->lpc_hc_irqstat & lpc->lpc_hc_irqmask;
 253         lpc_to_opb_irq = (irqs != 0);
 254     }
 255
 256     /* We don't honor the polarity register, it's pointless and unused
 257      * anyway
 258      */
 259     if (lpc_to_opb_irq) {
 260         lpc->opb_irq_input |= OPB_MASTER_IRQ_LPC;
 261     } else {
 262         lpc->opb_irq_input &= ~OPB_MASTER_IRQ_LPC;
 263     }
 264
 265     /* Update OPB internal latch */
 266     lpc->opb_irq_stat |= lpc->opb_irq_input & lpc->opb_irq_mask;
 267
 268     /* Reflect the interrupt */
 269     pnv_psi_irq_set(lpc->psi, PSIHB_IRQ_LPC_I2C, lpc->opb_irq_stat != 0);
 270 }
 271
 272 static uint64_t lpc_hc_read(void *opaque, hwaddr addr, unsigned size)
 273 {
 274     PnvLpcController *lpc = opaque;
 275     uint64_t val = 0xfffffffffffffffful;
 276
 277     switch (addr) {
 278     case LPC_HC_FW_SEG_IDSEL:
 279         val =  lpc->lpc_hc_fw_seg_idsel;
 280         break;
 281     case LPC_HC_FW_RD_ACC_SIZE:
 282         val =  lpc->lpc_hc_fw_rd_acc_size;
 283         break;
 284     case LPC_HC_IRQSER_CTRL:
 285         val =  lpc->lpc_hc_irqser_ctrl;
 286         break;
 287     case LPC_HC_IRQMASK:
 288         val =  lpc->lpc_hc_irqmask;
 289         break;
 290     case LPC_HC_IRQSTAT:
 291         val =  lpc->lpc_hc_irqstat;
 292         break;
 293     case LPC_HC_ERROR_ADDRESS:
 294         val =  lpc->lpc_hc_error_addr;
 295         break;
 296     default:
 297         qemu_log_mask(LOG_UNIMP, "LPC HC Unimplemented register: Ox%"
 298                       HWADDR_PRIx "\n", addr);
 299     }
 300     return val;
 301 }
 302
 303 static void lpc_hc_write(void *opaque, hwaddr addr, uint64_t val,
 304                          unsigned size)
 305 {
 306     PnvLpcController *lpc = opaque;
 307
 308     /* XXX Filter out reserved bits */
 309
 310     switch (addr) {
 311     case LPC_HC_FW_SEG_IDSEL:
 312         /* XXX Actually figure out how that works as this impact
 313          * memory regions/aliases
 314          */
 315         lpc->lpc_hc_fw_seg_idsel = val;
 316         break;
 317     case LPC_HC_FW_RD_ACC_SIZE:
 318         lpc->lpc_hc_fw_rd_acc_size = val;
 319         break;
 320     case LPC_HC_IRQSER_CTRL:
 321         lpc->lpc_hc_irqser_ctrl = val;
 322         pnv_lpc_eval_irqs(lpc);
 323         break;
 324     case LPC_HC_IRQMASK:
 325         lpc->lpc_hc_irqmask = val;
 326         pnv_lpc_eval_irqs(lpc);
 327         break;
 328     case LPC_HC_IRQSTAT:
 329         lpc->lpc_hc_irqstat &= ~val;
 330         pnv_lpc_eval_irqs(lpc);
 331         break;
 332     case LPC_HC_ERROR_ADDRESS:
 333         break;
 334     default:
 335         qemu_log_mask(LOG_UNIMP, "LPC HC Unimplemented register: Ox%"
 336                       HWADDR_PRIx "\n", addr);
 337     }
 338 }
 339
 340 static const MemoryRegionOps lpc_hc_ops = {
 341     .read = lpc_hc_read,
 342     .write = lpc_hc_write,
 343     .endianness = DEVICE_BIG_ENDIAN,
 344     .valid = {
 345         .min_access_size = 4,
 346         .max_access_size = 4,
 347     },
 348     .impl = {
 349         .min_access_size = 4,
 350         .max_access_size = 4,
 351     },
 352 };
 353
 354 static uint64_t opb_master_read(void *opaque, hwaddr addr, unsigned size)
 355 {
 356     PnvLpcController *lpc = opaque;
 357     uint64_t val = 0xfffffffffffffffful;
 358
 359     switch (addr) {
 360     case OPB_MASTER_LS_IRQ_STAT:
 361         val = lpc->opb_irq_stat;
 362         break;
 363     case OPB_MASTER_LS_IRQ_MASK:
 364         val = lpc->opb_irq_mask;
 365         break;
 366     case OPB_MASTER_LS_IRQ_POL:
 367         val = lpc->opb_irq_pol;
 368         break;
 369     case OPB_MASTER_LS_IRQ_INPUT:
 370         val = lpc->opb_irq_input;
 371         break;
 372     default:
 373         qemu_log_mask(LOG_UNIMP, "OPB MASTER Unimplemented register: Ox%"
 374                       HWADDR_PRIx "\n", addr);
 375     }
 376
 377     return val;
 378 }
 379
 380 static void opb_master_write(void *opaque, hwaddr addr,
 381                              uint64_t val, unsigned size)
 382 {
 383     PnvLpcController *lpc = opaque;
 384
 385     switch (addr) {
 386     case OPB_MASTER_LS_IRQ_STAT:
 387         lpc->opb_irq_stat &= ~val;
 388         pnv_lpc_eval_irqs(lpc);
 389         break;
 390     case OPB_MASTER_LS_IRQ_MASK:
 391         lpc->opb_irq_mask = val;
 392         pnv_lpc_eval_irqs(lpc);
 393         break;
 394     case OPB_MASTER_LS_IRQ_POL:
 395         lpc->opb_irq_pol = val;
 396         pnv_lpc_eval_irqs(lpc);
 397         break;
 398     case OPB_MASTER_LS_IRQ_INPUT:
 399         /* Read only */
 400         break;
 401     default:
 402         qemu_log_mask(LOG_UNIMP, "OPB MASTER Unimplemented register: Ox%"
 403                       HWADDR_PRIx "\n", addr);
 404     }
 405 }
 406
 407 static const MemoryRegionOps opb_master_ops = {
 408     .read = opb_master_read,
 409     .write = opb_master_write,
 410     .endianness = DEVICE_BIG_ENDIAN,
 411     .valid = {
 412         .min_access_size = 4,
 413         .max_access_size = 4,
 414     },
 415     .impl = {
 416         .min_access_size = 4,
 417         .max_access_size = 4,
 418     },
 419 };
 420
 421 static void pnv_lpc_realize(DeviceState *dev, Error **errp)
 422 {
 423     PnvLpcController *lpc = PNV_LPC(dev);
 424     Object *obj;
 425     Error *error = NULL;
 426
 427     /* Reg inits */
 428     lpc->lpc_hc_fw_rd_acc_size = LPC_HC_FW_RD_4B;
 429
 430     /* Create address space and backing MR for the OPB bus */
 431     memory_region_init(&lpc->opb_mr, OBJECT(dev), "lpc-opb", 0x100000000ull);
 432     address_space_init(&lpc->opb_as, &lpc->opb_mr, "lpc-opb");
 433
 434     /* Create ISA IO and Mem space regions which are the root of
 435      * the ISA bus (ie, ISA address spaces). We don't create a
 436      * separate one for FW which we alias to memory.
 437      */
 438     memory_region_init(&lpc->isa_io, OBJECT(dev), "isa-io", ISA_IO_SIZE);
 439     memory_region_init(&lpc->isa_mem, OBJECT(dev), "isa-mem", ISA_MEM_SIZE);
 440
 441     /* Create windows from the OPB space to the ISA space */
 442     memory_region_init_alias(&lpc->opb_isa_io, OBJECT(dev), "lpc-isa-io",
 443                              &lpc->isa_io, 0, LPC_IO_OPB_SIZE);
 444     memory_region_add_subregion(&lpc->opb_mr, LPC_IO_OPB_ADDR,
 445                                 &lpc->opb_isa_io);
 446     memory_region_init_alias(&lpc->opb_isa_mem, OBJECT(dev), "lpc-isa-mem",
 447                              &lpc->isa_mem, 0, LPC_MEM_OPB_SIZE);
 448     memory_region_add_subregion(&lpc->opb_mr, LPC_MEM_OPB_ADDR,
 449                                 &lpc->opb_isa_mem);
 450     memory_region_init_alias(&lpc->opb_isa_fw, OBJECT(dev), "lpc-isa-fw",
 451                              &lpc->isa_mem, 0, LPC_FW_OPB_SIZE);
 452     memory_region_add_subregion(&lpc->opb_mr, LPC_FW_OPB_ADDR,
 453                                 &lpc->opb_isa_fw);
 454
 455     /* Create MMIO regions for LPC HC and OPB registers */
 456     memory_region_init_io(&lpc->opb_master_regs, OBJECT(dev), &opb_master_ops,
 457                           lpc, "lpc-opb-master", LPC_OPB_REGS_OPB_SIZE);
 458     memory_region_add_subregion(&lpc->opb_mr, LPC_OPB_REGS_OPB_ADDR,
 459                                 &lpc->opb_master_regs);
 460     memory_region_init_io(&lpc->lpc_hc_regs, OBJECT(dev), &lpc_hc_ops, lpc,
 461                           "lpc-hc", LPC_HC_REGS_OPB_SIZE);
 462     memory_region_add_subregion(&lpc->opb_mr, LPC_HC_REGS_OPB_ADDR,
 463                                 &lpc->lpc_hc_regs);
 464
 465     /* XScom region for LPC registers */
 466     pnv_xscom_region_init(&lpc->xscom_regs, OBJECT(dev),
 467                           &pnv_lpc_xscom_ops, lpc, "xscom-lpc",
 468                           PNV_XSCOM_LPC_SIZE);
 469
 470     /* get PSI object from chip */
 471     obj = object_property_get_link(OBJECT(dev), "psi", &error);
 472     if (!obj) {
 473         error_setg(errp, "%s: required link 'psi' not found: %s",
 474                    __func__, error_get_pretty(error));
 475         return;
 476     }
 477     lpc->psi = PNV_PSI(obj);
 478 }
 479
 480 static void pnv_lpc_class_init(ObjectClass *klass, void *data)
 481 {
 482     DeviceClass *dc = DEVICE_CLASS(klass);
 483     PnvXScomInterfaceClass *xdc = PNV_XSCOM_INTERFACE_CLASS(klass);
 484
 485     xdc->populate = pnv_lpc_populate;
 486
 487     dc->realize = pnv_lpc_realize;
 488 }
 489
 490 static const TypeInfo pnv_lpc_info = {
 491     .name          = TYPE_PNV_LPC,
 492     .parent        = TYPE_DEVICE,
 493     .instance_size = sizeof(PnvLpcController),
 494     .class_init    = pnv_lpc_class_init,
 495     .interfaces = (InterfaceInfo[]) {
 496         { TYPE_PNV_XSCOM_INTERFACE },
 497         { }
 498     }
 499 };
 500
 501 static void pnv_lpc_register_types(void)
 502 {
 503     type_register_static(&pnv_lpc_info);
 504 }
 505
 506 type_init(pnv_lpc_register_types)
 507
 508 /* If we don't use the built-in LPC interrupt deserializer, we need
 509  * to provide a set of qirqs for the ISA bus or things will go bad.
 510  *
 511  * Most machines using pre-Naples chips (without said deserializer)
 512  * have a CPLD that will collect the SerIRQ and shoot them as a
 513  * single level interrupt to the P8 chip. So let's setup a hook
 514  * for doing just that.
 515  */
 516 static void pnv_lpc_isa_irq_handler_cpld(void *opaque, int n, int level)
 517 {
 518     PnvMachineState *pnv = POWERNV_MACHINE(qdev_get_machine());
 519     uint32_t old_state = pnv->cpld_irqstate;
 520     PnvLpcController *lpc = PNV_LPC(opaque);
 521
 522     if (level) {
 523         pnv->cpld_irqstate |= 1u << n;
 524     } else {
 525         pnv->cpld_irqstate &= ~(1u << n);
 526     }
 527
 528     if (pnv->cpld_irqstate != old_state) {
 529         pnv_psi_irq_set(lpc->psi, PSIHB_IRQ_EXTERNAL, pnv->cpld_irqstate != 0);
 530     }
 531 }
 532
 533 static void pnv_lpc_isa_irq_handler(void *opaque, int n, int level)
 534 {
 535     PnvLpcController *lpc = PNV_LPC(opaque);
 536
 537     /* The Naples HW latches the 1 levels, clearing is done by SW */
 538     if (level) {
 539         lpc->lpc_hc_irqstat |= LPC_HC_IRQ_SERIRQ0 >> n;
 540         pnv_lpc_eval_irqs(lpc);
 541     }
 542 }
 543
 544 qemu_irq *pnv_lpc_isa_irq_create(PnvLpcController *lpc, int chip_type,
 545                                  int nirqs)
 546 {
 547     /* Not all variants have a working serial irq decoder. If not,
 548      * handling of LPC interrupts becomes a platform issue (some
 549      * platforms have a CPLD to do it).
 550      */
 551     if (chip_type == PNV_CHIP_POWER8NVL) {
 552         return qemu_allocate_irqs(pnv_lpc_isa_irq_handler, lpc, nirqs);
 553     } else {
 554         return qemu_allocate_irqs(pnv_lpc_isa_irq_handler_cpld, lpc, nirqs);
 555     }
 556 }