hw/ssi/npcm_pspi.c

   1 /*
   2  * Nuvoton NPCM Peripheral SPI Module (PSPI)
   3  *
   4  * Copyright 2023 Google LLC
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  14  * for more details.
  15  */
  16
  17 #include "qemu/osdep.h"
  18
  19 #include "hw/irq.h"
  20 #include "hw/registerfields.h"
  21 #include "hw/ssi/npcm_pspi.h"
  22 #include "migration/vmstate.h"
  23 #include "qapi/error.h"
  24 #include "qemu/error-report.h"
  25 #include "qemu/log.h"
  26 #include "qemu/module.h"
  27 #include "qemu/units.h"
  28
  29 #include "trace.h"
  30
  31 REG16(PSPI_DATA, 0x0)
  32 REG16(PSPI_CTL1, 0x2)
  33     FIELD(PSPI_CTL1, SPIEN, 0,  1)
  34     FIELD(PSPI_CTL1, MOD,   2,  1)
  35     FIELD(PSPI_CTL1, EIR,   5,  1)
  36     FIELD(PSPI_CTL1, EIW,   6,  1)
  37     FIELD(PSPI_CTL1, SCM,   7,  1)
  38     FIELD(PSPI_CTL1, SCIDL, 8,  1)
  39     FIELD(PSPI_CTL1, SCDV,  9,  7)
  40 REG16(PSPI_STAT, 0x4)
  41     FIELD(PSPI_STAT, BSY,  0,  1)
  42     FIELD(PSPI_STAT, RBF,  1,  1)
  43
  44 static void npcm_pspi_update_irq(NPCMPSPIState *s)
  45 {
  46     int level = 0;
  47
  48     /* Only fire IRQ when the module is enabled. */
  49     if (FIELD_EX16(s->regs[R_PSPI_CTL1], PSPI_CTL1, SPIEN)) {
  50         /* Update interrupt as BSY is cleared. */
  51         if ((!FIELD_EX16(s->regs[R_PSPI_STAT], PSPI_STAT, BSY)) &&
  52             FIELD_EX16(s->regs[R_PSPI_CTL1], PSPI_CTL1, EIW)) {
  53             level = 1;
  54         }
  55
  56         /* Update interrupt as RBF is set. */
  57         if (FIELD_EX16(s->regs[R_PSPI_STAT], PSPI_STAT, RBF) &&
  58             FIELD_EX16(s->regs[R_PSPI_CTL1], PSPI_CTL1, EIR)) {
  59             level = 1;
  60         }
  61     }
  62     qemu_set_irq(s->irq, level);
  63 }
  64
  65 static uint16_t npcm_pspi_read_data(NPCMPSPIState *s)
  66 {
  67     uint16_t value = s->regs[R_PSPI_DATA];
  68
  69     /* Clear stat bits as the value are read out. */
  70     s->regs[R_PSPI_STAT] = 0;
  71
  72     return value;
  73 }
  74
  75 static void npcm_pspi_write_data(NPCMPSPIState *s, uint16_t data)
  76 {
  77     uint16_t value = 0;
  78
  79     if (FIELD_EX16(s->regs[R_PSPI_CTL1], PSPI_CTL1, MOD)) {
  80         value = ssi_transfer(s->spi, extract16(data, 8, 8)) << 8;
  81     }
  82     value |= ssi_transfer(s->spi, extract16(data, 0, 8));
  83     s->regs[R_PSPI_DATA] = value;
  84
  85     /* Mark data as available */
  86     s->regs[R_PSPI_STAT] = R_PSPI_STAT_BSY_MASK | R_PSPI_STAT_RBF_MASK;
  87 }
  88
  89 /* Control register read handler. */
  90 static uint64_t npcm_pspi_ctrl_read(void *opaque, hwaddr addr,
  91                                     unsigned int size)
  92 {
  93     NPCMPSPIState *s = opaque;
  94     uint16_t value;
  95
  96     switch (addr) {
  97     case A_PSPI_DATA:
  98         value = npcm_pspi_read_data(s);
  99         break;
 100
 101     case A_PSPI_CTL1:
 102         value = s->regs[R_PSPI_CTL1];
 103         break;
 104
 105     case A_PSPI_STAT:
 106         value = s->regs[R_PSPI_STAT];
 107         break;
 108
 109     default:
 110         qemu_log_mask(LOG_GUEST_ERROR,
 111                       "%s: write to invalid offset 0x%" PRIx64 "\n",
 112                       DEVICE(s)->canonical_path, addr);
 113         return 0;
 114     }
 115     trace_npcm_pspi_ctrl_read(DEVICE(s)->canonical_path, addr, value);
 116     npcm_pspi_update_irq(s);
 117
 118     return value;
 119 }
 120
 121 /* Control register write handler. */
 122 static void npcm_pspi_ctrl_write(void *opaque, hwaddr addr, uint64_t v,
 123                                  unsigned int size)
 124 {
 125     NPCMPSPIState *s = opaque;
 126     uint16_t value = v;
 127
 128     trace_npcm_pspi_ctrl_write(DEVICE(s)->canonical_path, addr, value);
 129
 130     switch (addr) {
 131     case A_PSPI_DATA:
 132         npcm_pspi_write_data(s, value);
 133         break;
 134
 135     case A_PSPI_CTL1:
 136         s->regs[R_PSPI_CTL1] = value;
 137         break;
 138
 139     case A_PSPI_STAT:
 140         qemu_log_mask(LOG_GUEST_ERROR,
 141                       "%s: write to read-only register PSPI_STAT: 0x%08"
 142                       PRIx64 "\n", DEVICE(s)->canonical_path, v);
 143         break;
 144
 145     default:
 146         qemu_log_mask(LOG_GUEST_ERROR,
 147                       "%s: write to invalid offset 0x%" PRIx64 "\n",
 148                       DEVICE(s)->canonical_path, addr);
 149         return;
 150     }
 151     npcm_pspi_update_irq(s);
 152 }
 153
 154 static const MemoryRegionOps npcm_pspi_ctrl_ops = {
 155     .read = npcm_pspi_ctrl_read,
 156     .write = npcm_pspi_ctrl_write,
 157     .endianness = DEVICE_LITTLE_ENDIAN,
 158     .valid = {
 159         .min_access_size = 1,
 160         .max_access_size = 2,
 161         .unaligned = false,
 162     },
 163     .impl = {
 164         .min_access_size = 2,
 165         .max_access_size = 2,
 166         .unaligned = false,
 167     },
 168 };
 169
 170 static void npcm_pspi_enter_reset(Object *obj, ResetType type)
 171 {
 172     NPCMPSPIState *s = NPCM_PSPI(obj);
 173
 174     trace_npcm_pspi_enter_reset(DEVICE(obj)->canonical_path, type);
 175     memset(s->regs, 0, sizeof(s->regs));
 176 }
 177
 178 static void npcm_pspi_realize(DeviceState *dev, Error **errp)
 179 {
 180     NPCMPSPIState *s = NPCM_PSPI(dev);
 181     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 182     Object *obj = OBJECT(dev);
 183
 184     s->spi = ssi_create_bus(dev, "pspi");
 185     memory_region_init_io(&s->mmio, obj, &npcm_pspi_ctrl_ops, s,
 186                           "mmio", 4 * KiB);
 187     sysbus_init_mmio(sbd, &s->mmio);
 188     sysbus_init_irq(sbd, &s->irq);
 189 }
 190
 191 static const VMStateDescription vmstate_npcm_pspi = {
 192     .name = "npcm-pspi",
 193     .version_id = 0,
 194     .minimum_version_id = 0,
 195     .fields = (VMStateField[]) {
 196         VMSTATE_UINT16_ARRAY(regs, NPCMPSPIState, NPCM_PSPI_NR_REGS),
 197         VMSTATE_END_OF_LIST(),
 198     },
 199 };
 200
 201
 202 static void npcm_pspi_class_init(ObjectClass *klass, void *data)
 203 {
 204     ResettableClass *rc = RESETTABLE_CLASS(klass);
 205     DeviceClass *dc = DEVICE_CLASS(klass);
 206
 207     dc->desc = "NPCM Peripheral SPI Module";
 208     dc->realize = npcm_pspi_realize;
 209     dc->vmsd = &vmstate_npcm_pspi;
 210     rc->phases.enter = npcm_pspi_enter_reset;
 211 }
 212
 213 static const TypeInfo npcm_pspi_types[] = {
 214     {
 215         .name = TYPE_NPCM_PSPI,
 216         .parent = TYPE_SYS_BUS_DEVICE,
 217         .instance_size = sizeof(NPCMPSPIState),
 218         .class_init = npcm_pspi_class_init,
 219     },
 220 };
 221 DEFINE_TYPES(npcm_pspi_types);