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/*
* Inter-Thread Communication Unit emulation.
*
* Copyright (c) 2016 Imagination Technologies
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "qapi/error.h"
#include "hw/core/cpu.h"
#include "hw/misc/mips_itu.h"
#include "hw/qdev-properties.h"
#include "target/mips/cpu.h"
#define ITC_TAG_ADDRSPACE_SZ (ITC_ADDRESSMAP_NUM * 8)
/* Initialize as 4kB area to fit all 32 cells with default 128B grain.
Storage may be resized by the software. */
#define ITC_STORAGE_ADDRSPACE_SZ 0x1000
#define ITC_FIFO_NUM_MAX 16
#define ITC_SEMAPH_NUM_MAX 16
#define ITC_AM1_NUMENTRIES_OFS 20
#define ITC_CELL_PV_MAX_VAL 0xFFFF
#define ITC_CELL_TAG_FIFO_DEPTH 28
#define ITC_CELL_TAG_FIFO_PTR 18
#define ITC_CELL_TAG_FIFO 17
#define ITC_CELL_TAG_T 16
#define ITC_CELL_TAG_F 1
#define ITC_CELL_TAG_E 0
#define ITC_AM0_BASE_ADDRESS_MASK 0xFFFFFC00ULL
#define ITC_AM0_EN_MASK 0x1
#define ITC_AM1_ADDR_MASK_MASK 0x1FC00
#define ITC_AM1_ENTRY_GRAIN_MASK 0x7
typedef enum ITCView {
ITCVIEW_BYPASS = 0,
ITCVIEW_CONTROL = 1,
ITCVIEW_EF_SYNC = 2,
ITCVIEW_EF_TRY = 3,
ITCVIEW_PV_SYNC = 4,
ITCVIEW_PV_TRY = 5,
ITCVIEW_PV_ICR0 = 15,
} ITCView;
#define ITC_ICR0_CELL_NUM 16
#define ITC_ICR0_BLK_GRAIN 8
#define ITC_ICR0_BLK_GRAIN_MASK 0x7
#define ITC_ICR0_ERR_AXI 2
#define ITC_ICR0_ERR_PARITY 1
#define ITC_ICR0_ERR_EXEC 0
MemoryRegion *mips_itu_get_tag_region(MIPSITUState *itu)
{
return &itu->tag_io;
}
static uint64_t itc_tag_read(void *opaque, hwaddr addr, unsigned size)
{
MIPSITUState *tag = (MIPSITUState *)opaque;
uint64_t index = addr >> 3;
if (index >= ITC_ADDRESSMAP_NUM) {
qemu_log_mask(LOG_GUEST_ERROR, "Read 0x%" PRIx64 "\n", addr);
return 0;
}
return tag->ITCAddressMap[index];
}
static void itc_reconfigure(MIPSITUState *tag)
{
uint64_t *am = &tag->ITCAddressMap[0];
MemoryRegion *mr = &tag->storage_io;
hwaddr address = am[0] & ITC_AM0_BASE_ADDRESS_MASK;
uint64_t size = (1 * KiB) + (am[1] & ITC_AM1_ADDR_MASK_MASK);
bool is_enabled = (am[0] & ITC_AM0_EN_MASK) != 0;
memory_region_transaction_begin();
if (!(size & (size - 1))) {
memory_region_set_size(mr, size);
}
memory_region_set_address(mr, address);
memory_region_set_enabled(mr, is_enabled);
memory_region_transaction_commit();
}
static void itc_tag_write(void *opaque, hwaddr addr,
uint64_t data, unsigned size)
{
MIPSITUState *tag = (MIPSITUState *)opaque;
uint64_t *am = &tag->ITCAddressMap[0];
uint64_t am_old, mask;
uint64_t index = addr >> 3;
switch (index) {
case 0:
mask = ITC_AM0_BASE_ADDRESS_MASK | ITC_AM0_EN_MASK;
break;
case 1:
mask = ITC_AM1_ADDR_MASK_MASK | ITC_AM1_ENTRY_GRAIN_MASK;
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "Bad write 0x%" PRIx64 "\n", addr);
return;
}
am_old = am[index];
am[index] = (data & mask) | (am_old & ~mask);
if (am_old != am[index]) {
itc_reconfigure(tag);
}
}
static const MemoryRegionOps itc_tag_ops = {
.read = itc_tag_read,
.write = itc_tag_write,
.impl = {
.max_access_size = 8,
},
.endianness = DEVICE_NATIVE_ENDIAN,
};
static inline uint32_t get_num_cells(MIPSITUState *s)
{
return s->num_fifo + s->num_semaphores;
}
static inline ITCView get_itc_view(hwaddr addr)
{
return (addr >> 3) & 0xf;
}
static inline int get_cell_stride_shift(const MIPSITUState *s)
{
/* Minimum interval (for EntryGain = 0) is 128 B */
return 7 + (s->ITCAddressMap[1] & ITC_AM1_ENTRY_GRAIN_MASK);
}
static inline ITCStorageCell *get_cell(MIPSITUState *s,
hwaddr addr)
{
uint32_t cell_idx = addr >> get_cell_stride_shift(s);
uint32_t num_cells = get_num_cells(s);
if (cell_idx >= num_cells) {
cell_idx = num_cells - 1;
}
return &s->cell[cell_idx];
}
static void wake_blocked_threads(ITCStorageCell *c)
{
CPUState *cs;
CPU_FOREACH(cs) {
if (cs->halted && (c->blocked_threads & (1ULL << cs->cpu_index))) {
cpu_interrupt(cs, CPU_INTERRUPT_WAKE);
}
}
c->blocked_threads = 0;
}
static G_NORETURN
void block_thread_and_exit(ITCStorageCell *c)
{
c->blocked_threads |= 1ULL << current_cpu->cpu_index;
current_cpu->halted = 1;
current_cpu->exception_index = EXCP_HLT;
cpu_loop_exit_restore(current_cpu, current_cpu->mem_io_pc);
}
/* ITC Bypass View */
static inline uint64_t view_bypass_read(ITCStorageCell *c)
{
if (c->tag.FIFO) {
return c->data[c->fifo_out];
} else {
return c->data[0];
}
}
static inline void view_bypass_write(ITCStorageCell *c, uint64_t val)
{
if (c->tag.FIFO && (c->tag.FIFOPtr > 0)) {
int idx = (c->fifo_out + c->tag.FIFOPtr - 1) % ITC_CELL_DEPTH;
c->data[idx] = val;
}
/* ignore a write to the semaphore cell */
}
/* ITC Control View */
static inline uint64_t view_control_read(ITCStorageCell *c)
{
return ((uint64_t)c->tag.FIFODepth << ITC_CELL_TAG_FIFO_DEPTH) |
(c->tag.FIFOPtr << ITC_CELL_TAG_FIFO_PTR) |
(c->tag.FIFO << ITC_CELL_TAG_FIFO) |
(c->tag.T << ITC_CELL_TAG_T) |
(c->tag.E << ITC_CELL_TAG_E) |
(c->tag.F << ITC_CELL_TAG_F);
}
static inline void view_control_write(ITCStorageCell *c, uint64_t val)
{
c->tag.T = (val >> ITC_CELL_TAG_T) & 1;
c->tag.E = (val >> ITC_CELL_TAG_E) & 1;
c->tag.F = (val >> ITC_CELL_TAG_F) & 1;
if (c->tag.E) {
c->tag.FIFOPtr = 0;
}
}
/* ITC Empty/Full View */
static uint64_t view_ef_common_read(ITCStorageCell *c, bool blocking)
{
uint64_t ret = 0;
if (!c->tag.FIFO) {
return 0;
}
c->tag.F = 0;
if (blocking && c->tag.E) {
block_thread_and_exit(c);
}
if (c->blocked_threads) {
wake_blocked_threads(c);
}
if (c->tag.FIFOPtr > 0) {
ret = c->data[c->fifo_out];
c->fifo_out = (c->fifo_out + 1) % ITC_CELL_DEPTH;
c->tag.FIFOPtr--;
}
if (c->tag.FIFOPtr == 0) {
c->tag.E = 1;
}
return ret;
}
static uint64_t view_ef_sync_read(ITCStorageCell *c)
{
return view_ef_common_read(c, true);
}
static uint64_t view_ef_try_read(ITCStorageCell *c)
{
return view_ef_common_read(c, false);
}
static inline void view_ef_common_write(ITCStorageCell *c, uint64_t val,
bool blocking)
{
if (!c->tag.FIFO) {
return;
}
c->tag.E = 0;
if (blocking && c->tag.F) {
block_thread_and_exit(c);
}
if (c->blocked_threads) {
wake_blocked_threads(c);
}
if (c->tag.FIFOPtr < ITC_CELL_DEPTH) {
int idx = (c->fifo_out + c->tag.FIFOPtr) % ITC_CELL_DEPTH;
c->data[idx] = val;
c->tag.FIFOPtr++;
}
if (c->tag.FIFOPtr == ITC_CELL_DEPTH) {
c->tag.F = 1;
}
}
static void view_ef_sync_write(ITCStorageCell *c, uint64_t val)
{
view_ef_common_write(c, val, true);
}
static void view_ef_try_write(ITCStorageCell *c, uint64_t val)
{
view_ef_common_write(c, val, false);
}
/* ITC P/V View */
static uint64_t view_pv_common_read(ITCStorageCell *c, bool blocking)
{
uint64_t ret = c->data[0];
if (c->tag.FIFO) {
return 0;
}
if (c->data[0] > 0) {
c->data[0]--;
} else if (blocking) {
block_thread_and_exit(c);
}
return ret;
}
static uint64_t view_pv_sync_read(ITCStorageCell *c)
{
return view_pv_common_read(c, true);
}
static uint64_t view_pv_try_read(ITCStorageCell *c)
{
return view_pv_common_read(c, false);
}
static inline void view_pv_common_write(ITCStorageCell *c)
{
if (c->tag.FIFO) {
return;
}
if (c->data[0] < ITC_CELL_PV_MAX_VAL) {
c->data[0]++;
}
if (c->blocked_threads) {
wake_blocked_threads(c);
}
}
static void view_pv_sync_write(ITCStorageCell *c)
{
view_pv_common_write(c);
}
static void view_pv_try_write(ITCStorageCell *c)
{
view_pv_common_write(c);
}
static void raise_exception(int excp)
{
current_cpu->exception_index = excp;
cpu_loop_exit(current_cpu);
}
static uint64_t itc_storage_read(void *opaque, hwaddr addr, unsigned size)
{
MIPSITUState *s = (MIPSITUState *)opaque;
ITCStorageCell *cell = get_cell(s, addr);
ITCView view = get_itc_view(addr);
uint64_t ret = -1;
switch (size) {
case 1:
case 2:
s->icr0 |= 1 << ITC_ICR0_ERR_AXI;
raise_exception(EXCP_DBE);
return 0;
}
switch (view) {
case ITCVIEW_BYPASS:
ret = view_bypass_read(cell);
break;
case ITCVIEW_CONTROL:
ret = view_control_read(cell);
break;
case ITCVIEW_EF_SYNC:
ret = view_ef_sync_read(cell);
break;
case ITCVIEW_EF_TRY:
ret = view_ef_try_read(cell);
break;
case ITCVIEW_PV_SYNC:
ret = view_pv_sync_read(cell);
break;
case ITCVIEW_PV_TRY:
ret = view_pv_try_read(cell);
break;
case ITCVIEW_PV_ICR0:
ret = s->icr0;
break;
default:
qemu_log_mask(LOG_GUEST_ERROR,
"itc_storage_read: Bad ITC View %d\n", (int)view);
break;
}
return ret;
}
static void itc_storage_write(void *opaque, hwaddr addr, uint64_t data,
unsigned size)
{
MIPSITUState *s = (MIPSITUState *)opaque;
ITCStorageCell *cell = get_cell(s, addr);
ITCView view = get_itc_view(addr);
switch (size) {
case 1:
case 2:
s->icr0 |= 1 << ITC_ICR0_ERR_AXI;
raise_exception(EXCP_DBE);
return;
}
switch (view) {
case ITCVIEW_BYPASS:
view_bypass_write(cell, data);
break;
case ITCVIEW_CONTROL:
view_control_write(cell, data);
break;
case ITCVIEW_EF_SYNC:
view_ef_sync_write(cell, data);
break;
case ITCVIEW_EF_TRY:
view_ef_try_write(cell, data);
break;
case ITCVIEW_PV_SYNC:
view_pv_sync_write(cell);
break;
case ITCVIEW_PV_TRY:
view_pv_try_write(cell);
break;
case ITCVIEW_PV_ICR0:
if (data & 0x7) {
/* clear ERROR bits */
s->icr0 &= ~(data & 0x7);
}
/* set BLK_GRAIN */
s->icr0 &= ~0x700;
s->icr0 |= data & 0x700;
break;
default:
qemu_log_mask(LOG_GUEST_ERROR,
"itc_storage_write: Bad ITC View %d\n", (int)view);
break;
}
}
static const MemoryRegionOps itc_storage_ops = {
.read = itc_storage_read,
.write = itc_storage_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static void itc_reset_cells(MIPSITUState *s)
{
int i;
memset(s->cell, 0, get_num_cells(s) * sizeof(s->cell[0]));
for (i = 0; i < s->num_fifo; i++) {
s->cell[i].tag.E = 1;
s->cell[i].tag.FIFO = 1;
s->cell[i].tag.FIFODepth = ITC_CELL_DEPTH_SHIFT;
}
}
static void mips_itu_init(Object *obj)
{
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
MIPSITUState *s = MIPS_ITU(obj);
memory_region_init_io(&s->storage_io, OBJECT(s), &itc_storage_ops, s,
"mips-itc-storage", ITC_STORAGE_ADDRSPACE_SZ);
sysbus_init_mmio(sbd, &s->storage_io);
memory_region_init_io(&s->tag_io, OBJECT(s), &itc_tag_ops, s,
"mips-itc-tag", ITC_TAG_ADDRSPACE_SZ);
}
static void mips_itu_realize(DeviceState *dev, Error **errp)
{
MIPSITUState *s = MIPS_ITU(dev);
if (s->num_fifo > ITC_FIFO_NUM_MAX) {
error_setg(errp, "Exceed maximum number of FIFO cells: %d",
s->num_fifo);
return;
}
if (s->num_semaphores > ITC_SEMAPH_NUM_MAX) {
error_setg(errp, "Exceed maximum number of Semaphore cells: %d",
s->num_semaphores);
return;
}
s->cell = g_new(ITCStorageCell, get_num_cells(s));
}
static void mips_itu_reset(DeviceState *dev)
{
MIPSITUState *s = MIPS_ITU(dev);
s->ITCAddressMap[0] = 0;
s->ITCAddressMap[1] =
((ITC_STORAGE_ADDRSPACE_SZ - 1) & ITC_AM1_ADDR_MASK_MASK) |
(get_num_cells(s) << ITC_AM1_NUMENTRIES_OFS);
itc_reconfigure(s);
itc_reset_cells(s);
}
static Property mips_itu_properties[] = {
DEFINE_PROP_UINT32("num-fifo", MIPSITUState, num_fifo,
ITC_FIFO_NUM_MAX),
DEFINE_PROP_UINT32("num-semaphores", MIPSITUState, num_semaphores,
ITC_SEMAPH_NUM_MAX),
DEFINE_PROP_END_OF_LIST(),
};
static void mips_itu_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
device_class_set_props(dc, mips_itu_properties);
dc->realize = mips_itu_realize;
dc->reset = mips_itu_reset;
}
static const TypeInfo mips_itu_info = {
.name = TYPE_MIPS_ITU,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(MIPSITUState),
.instance_init = mips_itu_init,
.class_init = mips_itu_class_init,
};
static void mips_itu_register_types(void)
{
type_register_static(&mips_itu_info);
}
type_init(mips_itu_register_types)