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qemu/hw/ppc/pnv_chiptod.c
Nicholas Piggin cde2ba34a9 ppc/pnv: Implement the ChipTOD to Core transfer 
One of the functions of the ChipTOD is to transfer TOD to the Core
(aka PC - Pervasive Core) timebase facility.

The ChipTOD can be programmed with a target address to send the TOD
value to. The hardware implementation seems to perform this by
sending the TOD value to a SCOM address.

This implementation grabs the core directly and manipulates the
timebase facility state in the core. This is a hack, but it works
enough for now. A better implementation would implement the transfer
to the PnvCore xscom register and drive the timebase state machine
from there.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
2024-02-23 23:24:43 +10:00

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/*
* QEMU PowerPC PowerNV Emulation of some ChipTOD behaviour
*
* Copyright (c) 2022-2023, IBM Corporation.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* ChipTOD (aka TOD) is a facility implemented in the nest / pervasive. The
* purpose is to keep time-of-day across chips and cores.
*
* There is a master chip TOD, which sends signals to slave chip TODs to
* keep them synchronized. There are two sets of configuration registers
* called primary and secondary, which can be used fail over.
*
* The chip TOD also distributes synchronisation signals to the timebase
* facility in each of the cores on the chip. In particular there is a
* feature that can move the TOD value in the ChipTOD to and from the TB.
*
* Initialisation typically brings all ChipTOD into sync (see tod_state),
* and then brings each core TB into sync with the ChipTODs (see timebase
* state and TFMR). This model is a very basic simulation of the init sequence
* performed by skiboot.
*/
#include "qemu/osdep.h"
#include "sysemu/reset.h"
#include "target/ppc/cpu.h"
#include "qapi/error.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "hw/irq.h"
#include "hw/qdev-properties.h"
#include "hw/ppc/fdt.h"
#include "hw/ppc/ppc.h"
#include "hw/ppc/pnv.h"
#include "hw/ppc/pnv_chip.h"
#include "hw/ppc/pnv_core.h"
#include "hw/ppc/pnv_xscom.h"
#include "hw/ppc/pnv_chiptod.h"
#include "trace.h"
#include <libfdt.h>
/* TOD chip XSCOM addresses */
#define TOD_M_PATH_CTRL_REG 0x00000000 /* Master Path ctrl reg */
#define TOD_PRI_PORT_0_CTRL_REG 0x00000001 /* Primary port0 ctrl reg */
#define TOD_PRI_PORT_1_CTRL_REG 0x00000002 /* Primary port1 ctrl reg */
#define TOD_SEC_PORT_0_CTRL_REG 0x00000003 /* Secondary p0 ctrl reg */
#define TOD_SEC_PORT_1_CTRL_REG 0x00000004 /* Secondary p1 ctrl reg */
#define TOD_S_PATH_CTRL_REG 0x00000005 /* Slave Path ctrl reg */
#define TOD_I_PATH_CTRL_REG 0x00000006 /* Internal Path ctrl reg */
/* -- TOD primary/secondary master/slave control register -- */
#define TOD_PSS_MSS_CTRL_REG 0x00000007
/* -- TOD primary/secondary master/slave status register -- */
#define TOD_PSS_MSS_STATUS_REG 0x00000008
/* TOD chip XSCOM addresses */
#define TOD_CHIP_CTRL_REG 0x00000010 /* Chip control reg */
#define TOD_TX_TTYPE_0_REG 0x00000011
#define TOD_TX_TTYPE_1_REG 0x00000012 /* PSS switch reg */
#define TOD_TX_TTYPE_2_REG 0x00000013 /* Enable step checkers */
#define TOD_TX_TTYPE_3_REG 0x00000014 /* Request TOD reg */
#define TOD_TX_TTYPE_4_REG 0x00000015 /* Send TOD reg */
#define TOD_TX_TTYPE_5_REG 0x00000016 /* Invalidate TOD reg */
#define TOD_MOVE_TOD_TO_TB_REG 0x00000017
#define TOD_LOAD_TOD_MOD_REG 0x00000018
#define TOD_LOAD_TOD_REG 0x00000021
#define TOD_START_TOD_REG 0x00000022
#define TOD_FSM_REG 0x00000024
#define TOD_TX_TTYPE_CTRL_REG 0x00000027 /* TX TTYPE Control reg */
#define TOD_TX_TTYPE_PIB_SLAVE_ADDR PPC_BITMASK(26, 31)
/* -- TOD Error interrupt register -- */
#define TOD_ERROR_REG 0x00000030
/* PC unit PIB address which recieves the timebase transfer from TOD */
#define PC_TOD 0x4A3
/*
* The TOD FSM:
* - The reset state is 0 error.
* - A hardware error detected will transition to state 0 from any state.
* - LOAD_TOD_MOD and TTYPE5 will transition to state 7 from any state.
*
* | state | action | new |
* |------------+------------------------------+-----|
* | 0 error | LOAD_TOD_MOD | 7 |
* | 0 error | Recv TTYPE5 (invalidate TOD) | 7 |
* | 7 not_set | LOAD_TOD (bit-63 = 0) | 2 |
* | 7 not_set | LOAD_TOD (bit-63 = 1) | 1 |
* | 7 not_set | Recv TTYPE4 (send TOD) | 2 |
* | 2 running | | |
* | 1 stopped | START_TOD | 2 |
*
* Note the hardware has additional states but they relate to the sending
* and receiving and waiting on synchronisation signals between chips and
* are not described or modeled here.
*/
static uint64_t pnv_chiptod_xscom_read(void *opaque, hwaddr addr,
unsigned size)
{
PnvChipTOD *chiptod = PNV_CHIPTOD(opaque);
uint32_t offset = addr >> 3;
uint64_t val = 0;
switch (offset) {
case TOD_PSS_MSS_STATUS_REG:
/*
* ChipTOD does not support configurations other than primary
* master, does not support errors, etc.
*/
val |= PPC_BITMASK(6, 10); /* STEP checker validity */
val |= PPC_BIT(12); /* Primary config master path select */
if (chiptod->tod_state == tod_running) {
val |= PPC_BIT(20); /* Is running */
}
val |= PPC_BIT(21); /* Is using primary config */
val |= PPC_BIT(26); /* Is using master path select */
if (chiptod->primary) {
val |= PPC_BIT(23); /* Is active master */
} else if (chiptod->secondary) {
val |= PPC_BIT(24); /* Is backup master */
} else {
val |= PPC_BIT(25); /* Is slave (should backup master set this?) */
}
break;
case TOD_PSS_MSS_CTRL_REG:
val = chiptod->pss_mss_ctrl_reg;
break;
case TOD_TX_TTYPE_CTRL_REG:
val = 0;
break;
case TOD_ERROR_REG:
val = chiptod->tod_error;
break;
case TOD_FSM_REG:
if (chiptod->tod_state == tod_running) {
val |= PPC_BIT(4);
}
break;
default:
qemu_log_mask(LOG_UNIMP, "pnv_chiptod: unimplemented register: Ox%"
HWADDR_PRIx "\n", addr >> 3);
}
trace_pnv_chiptod_xscom_read(addr >> 3, val);
return val;
}
static void chiptod_receive_ttype(PnvChipTOD *chiptod, uint32_t trigger)
{
switch (trigger) {
case TOD_TX_TTYPE_4_REG:
if (chiptod->tod_state != tod_not_set) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: received TTYPE4 in "
" state %d, should be in 7 (TOD_NOT_SET)\n",
chiptod->tod_state);
} else {
chiptod->tod_state = tod_running;
}
break;
case TOD_TX_TTYPE_5_REG:
/* Works from any state */
chiptod->tod_state = tod_not_set;
break;
default:
qemu_log_mask(LOG_UNIMP, "pnv_chiptod: received unimplemented "
" TTYPE %u\n", trigger);
break;
}
}
static void chiptod_power9_broadcast_ttype(PnvChipTOD *sender,
uint32_t trigger)
{
PnvMachineState *pnv = PNV_MACHINE(qdev_get_machine());
int i;
for (i = 0; i < pnv->num_chips; i++) {
Pnv9Chip *chip9 = PNV9_CHIP(pnv->chips[i]);
PnvChipTOD *chiptod = &chip9->chiptod;
if (chiptod != sender) {
chiptod_receive_ttype(chiptod, trigger);
}
}
}
static void chiptod_power10_broadcast_ttype(PnvChipTOD *sender,
uint32_t trigger)
{
PnvMachineState *pnv = PNV_MACHINE(qdev_get_machine());
int i;
for (i = 0; i < pnv->num_chips; i++) {
Pnv10Chip *chip10 = PNV10_CHIP(pnv->chips[i]);
PnvChipTOD *chiptod = &chip10->chiptod;
if (chiptod != sender) {
chiptod_receive_ttype(chiptod, trigger);
}
}
}
static PnvCore *pnv_chip_get_core_by_xscom_base(PnvChip *chip,
uint32_t xscom_base)
{
PnvChipClass *pcc = PNV_CHIP_GET_CLASS(chip);
int i;
for (i = 0; i < chip->nr_cores; i++) {
PnvCore *pc = chip->cores[i];
CPUCore *cc = CPU_CORE(pc);
int core_hwid = cc->core_id;
if (pcc->xscom_core_base(chip, core_hwid) == xscom_base) {
return pc;
}
}
return NULL;
}
static PnvCore *chiptod_power9_tx_ttype_target(PnvChipTOD *chiptod,
uint64_t val)
{
/*
* skiboot uses Core ID for P9, though SCOM should work too.
*/
if (val & PPC_BIT(35)) { /* SCOM addressing */
uint32_t addr = val >> 32;
uint32_t reg = addr & 0xfff;
if (reg != PC_TOD) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: SCOM addressing: "
"unimplemented slave register 0x%" PRIx32 "\n", reg);
return NULL;
}
return pnv_chip_get_core_by_xscom_base(chiptod->chip, addr & ~0xfff);
} else { /* Core ID addressing */
uint32_t core_id = GETFIELD(TOD_TX_TTYPE_PIB_SLAVE_ADDR, val) & 0x1f;
return pnv_chip_find_core(chiptod->chip, core_id);
}
}
static PnvCore *chiptod_power10_tx_ttype_target(PnvChipTOD *chiptod,
uint64_t val)
{
/*
* skiboot uses SCOM for P10 because Core ID was unable to be made to
* work correctly. For this reason only SCOM addressing is implemented.
*/
if (val & PPC_BIT(35)) { /* SCOM addressing */
uint32_t addr = val >> 32;
uint32_t reg = addr & 0xfff;
if (reg != PC_TOD) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: SCOM addressing: "
"unimplemented slave register 0x%" PRIx32 "\n", reg);
return NULL;
}
/*
* This may not deal with P10 big-core addressing at the moment.
* The big-core code in skiboot syncs small cores, but it targets
* the even PIR (first small-core) when syncing second small-core.
*/
return pnv_chip_get_core_by_xscom_base(chiptod->chip, addr & ~0xfff);
} else { /* Core ID addressing */
qemu_log_mask(LOG_UNIMP, "pnv_chiptod: TX TTYPE Core ID "
"addressing is not implemented for POWER10\n");
return NULL;
}
}
static void pnv_chiptod_xscom_write(void *opaque, hwaddr addr,
uint64_t val, unsigned size)
{
PnvChipTOD *chiptod = PNV_CHIPTOD(opaque);
PnvChipTODClass *pctc = PNV_CHIPTOD_GET_CLASS(chiptod);
uint32_t offset = addr >> 3;
trace_pnv_chiptod_xscom_write(addr >> 3, val);
switch (offset) {
case TOD_PSS_MSS_CTRL_REG:
/* Is this correct? */
if (chiptod->primary) {
val |= PPC_BIT(1); /* TOD is master */
} else {
val &= ~PPC_BIT(1);
}
val |= PPC_BIT(2); /* Drawer is master (don't simulate multi-drawer) */
chiptod->pss_mss_ctrl_reg = val & PPC_BITMASK(0, 31);
break;
case TOD_TX_TTYPE_CTRL_REG:
/*
* This register sets the target of the TOD value transfer initiated
* by TOD_MOVE_TOD_TO_TB. The TOD is able to send the address to
* any target register, though in practice only the PC TOD register
* should be used. ChipTOD has a "SCOM addressing" mode which fully
* specifies the SCOM address, and a core-ID mode which uses the
* core ID to target the PC TOD for a given core.
*/
chiptod->slave_pc_target = pctc->tx_ttype_target(chiptod, val);
if (!chiptod->slave_pc_target) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: xscom write reg"
" TOD_TX_TTYPE_CTRL_REG val 0x%" PRIx64
" invalid slave address\n", val);
}
break;
case TOD_ERROR_REG:
chiptod->tod_error &= ~val;
break;
case TOD_LOAD_TOD_MOD_REG:
if (!(val & PPC_BIT(0))) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: xscom write reg"
" TOD_LOAD_TOD_MOD_REG with bad val 0x%" PRIx64"\n",
val);
} else {
chiptod->tod_state = tod_not_set;
}
break;
case TOD_LOAD_TOD_REG:
if (chiptod->tod_state != tod_not_set) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: LOAD_TOG_REG in "
" state %d, should be in 7 (TOD_NOT_SET)\n",
chiptod->tod_state);
} else {
if (val & PPC_BIT(63)) {
chiptod->tod_state = tod_stopped;
} else {
chiptod->tod_state = tod_running;
}
}
break;
case TOD_MOVE_TOD_TO_TB_REG:
/*
* XXX: it should be a cleaner model to have this drive a SCOM
* transaction to the target address, and implement the state machine
* in the PnvCore. For now, this hack makes things work.
*/
if (chiptod->tod_state != tod_running) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: xscom write reg"
" TOD_MOVE_TOD_TO_TB_REG in bad state %d\n",
chiptod->tod_state);
} else if (!(val & PPC_BIT(0))) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: xscom write reg"
" TOD_MOVE_TOD_TO_TB_REG with bad val 0x%" PRIx64"\n",
val);
} else if (chiptod->slave_pc_target == NULL) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: xscom write reg"
" TOD_MOVE_TOD_TO_TB_REG with no slave target\n");
} else {
PowerPCCPU *cpu = chiptod->slave_pc_target->threads[0];
CPUPPCState *env = &cpu->env;
/*
* Moving TOD to TB will set the TB of all threads in a
* core, so skiboot only does this once per thread0, so
* that is where we keep the timebase state machine.
*
* It is likely possible for TBST to be driven from other
* threads in the core, but for now we only implement it for
* thread 0.
*/
if (env->pnv_tod_tbst.tb_ready_for_tod) {
env->pnv_tod_tbst.tod_sent_to_tb = 1;
} else {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: xscom write reg"
" TOD_MOVE_TOD_TO_TB_REG with TB not ready to"
" receive TOD\n");
}
}
break;
case TOD_START_TOD_REG:
if (chiptod->tod_state != tod_stopped) {
qemu_log_mask(LOG_GUEST_ERROR, "pnv_chiptod: LOAD_TOG_REG in "
" state %d, should be in 1 (TOD_STOPPED)\n",
chiptod->tod_state);
} else {
chiptod->tod_state = tod_running;
}
break;
case TOD_TX_TTYPE_4_REG:
case TOD_TX_TTYPE_5_REG:
pctc->broadcast_ttype(chiptod, offset);
break;
default:
qemu_log_mask(LOG_UNIMP, "pnv_chiptod: unimplemented register: Ox%"
HWADDR_PRIx "\n", addr >> 3);
}
}
static const MemoryRegionOps pnv_chiptod_xscom_ops = {
.read = pnv_chiptod_xscom_read,
.write = pnv_chiptod_xscom_write,
.valid.min_access_size = 8,
.valid.max_access_size = 8,
.impl.min_access_size = 8,
.impl.max_access_size = 8,
.endianness = DEVICE_BIG_ENDIAN,
};
static int pnv_chiptod_dt_xscom(PnvXScomInterface *dev, void *fdt,
int xscom_offset,
const char compat[], size_t compat_size)
{
PnvChipTOD *chiptod = PNV_CHIPTOD(dev);
g_autofree char *name = NULL;
int offset;
uint32_t chiptod_pcba = PNV9_XSCOM_CHIPTOD_BASE;
uint32_t reg[] = {
cpu_to_be32(chiptod_pcba),
cpu_to_be32(PNV9_XSCOM_CHIPTOD_SIZE)
};
name = g_strdup_printf("chiptod@%x", chiptod_pcba);
offset = fdt_add_subnode(fdt, xscom_offset, name);
_FDT(offset);
if (chiptod->primary) {
_FDT((fdt_setprop(fdt, offset, "primary", NULL, 0)));
} else if (chiptod->secondary) {
_FDT((fdt_setprop(fdt, offset, "secondary", NULL, 0)));
}
_FDT((fdt_setprop(fdt, offset, "reg", reg, sizeof(reg))));
_FDT((fdt_setprop(fdt, offset, "compatible", compat, compat_size)));
return 0;
}
static int pnv_chiptod_power9_dt_xscom(PnvXScomInterface *dev, void *fdt,
int xscom_offset)
{
const char compat[] = "ibm,power-chiptod\0ibm,power9-chiptod";
return pnv_chiptod_dt_xscom(dev, fdt, xscom_offset, compat, sizeof(compat));
}
static Property pnv_chiptod_properties[] = {
DEFINE_PROP_BOOL("primary", PnvChipTOD, primary, false),
DEFINE_PROP_BOOL("secondary", PnvChipTOD, secondary, false),
DEFINE_PROP_LINK("chip", PnvChipTOD , chip, TYPE_PNV_CHIP, PnvChip *),
DEFINE_PROP_END_OF_LIST(),
};
static void pnv_chiptod_power9_class_init(ObjectClass *klass, void *data)
{
PnvChipTODClass *pctc = PNV_CHIPTOD_CLASS(klass);
DeviceClass *dc = DEVICE_CLASS(klass);
PnvXScomInterfaceClass *xdc = PNV_XSCOM_INTERFACE_CLASS(klass);
dc->desc = "PowerNV ChipTOD Controller (POWER9)";
device_class_set_props(dc, pnv_chiptod_properties);
xdc->dt_xscom = pnv_chiptod_power9_dt_xscom;
pctc->broadcast_ttype = chiptod_power9_broadcast_ttype;
pctc->tx_ttype_target = chiptod_power9_tx_ttype_target;
pctc->xscom_size = PNV_XSCOM_CHIPTOD_SIZE;
}
static const TypeInfo pnv_chiptod_power9_type_info = {
.name = TYPE_PNV9_CHIPTOD,
.parent = TYPE_PNV_CHIPTOD,
.instance_size = sizeof(PnvChipTOD),
.class_init = pnv_chiptod_power9_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_PNV_XSCOM_INTERFACE },
{ }
}
};
static int pnv_chiptod_power10_dt_xscom(PnvXScomInterface *dev, void *fdt,
int xscom_offset)
{
const char compat[] = "ibm,power-chiptod\0ibm,power10-chiptod";
return pnv_chiptod_dt_xscom(dev, fdt, xscom_offset, compat, sizeof(compat));
}
static void pnv_chiptod_power10_class_init(ObjectClass *klass, void *data)
{
PnvChipTODClass *pctc = PNV_CHIPTOD_CLASS(klass);
DeviceClass *dc = DEVICE_CLASS(klass);
PnvXScomInterfaceClass *xdc = PNV_XSCOM_INTERFACE_CLASS(klass);
dc->desc = "PowerNV ChipTOD Controller (POWER10)";
device_class_set_props(dc, pnv_chiptod_properties);
xdc->dt_xscom = pnv_chiptod_power10_dt_xscom;
pctc->broadcast_ttype = chiptod_power10_broadcast_ttype;
pctc->tx_ttype_target = chiptod_power10_tx_ttype_target;
pctc->xscom_size = PNV_XSCOM_CHIPTOD_SIZE;
}
static const TypeInfo pnv_chiptod_power10_type_info = {
.name = TYPE_PNV10_CHIPTOD,
.parent = TYPE_PNV_CHIPTOD,
.instance_size = sizeof(PnvChipTOD),
.class_init = pnv_chiptod_power10_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_PNV_XSCOM_INTERFACE },
{ }
}
};
static void pnv_chiptod_reset(void *dev)
{
PnvChipTOD *chiptod = PNV_CHIPTOD(dev);
chiptod->pss_mss_ctrl_reg = 0;
if (chiptod->primary) {
chiptod->pss_mss_ctrl_reg |= PPC_BIT(1); /* TOD is master */
}
/* Drawer is master (we do not simulate multi-drawer) */
chiptod->pss_mss_ctrl_reg |= PPC_BIT(2);
chiptod->tod_error = 0;
chiptod->tod_state = tod_error;
}
static void pnv_chiptod_realize(DeviceState *dev, Error **errp)
{
PnvChipTOD *chiptod = PNV_CHIPTOD(dev);
PnvChipTODClass *pctc = PNV_CHIPTOD_GET_CLASS(chiptod);
/* XScom regions for ChipTOD registers */
pnv_xscom_region_init(&chiptod->xscom_regs, OBJECT(dev),
&pnv_chiptod_xscom_ops, chiptod, "xscom-chiptod",
pctc->xscom_size);
qemu_register_reset(pnv_chiptod_reset, chiptod);
}
static void pnv_chiptod_unrealize(DeviceState *dev)
{
PnvChipTOD *chiptod = PNV_CHIPTOD(dev);
qemu_unregister_reset(pnv_chiptod_reset, chiptod);
}
static void pnv_chiptod_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = pnv_chiptod_realize;
dc->unrealize = pnv_chiptod_unrealize;
dc->desc = "PowerNV ChipTOD Controller";
dc->user_creatable = false;
}
static const TypeInfo pnv_chiptod_type_info = {
.name = TYPE_PNV_CHIPTOD,
.parent = TYPE_DEVICE,
.instance_size = sizeof(PnvChipTOD),
.class_init = pnv_chiptod_class_init,
.class_size = sizeof(PnvChipTODClass),
.abstract = true,
};
static void pnv_chiptod_register_types(void)
{
type_register_static(&pnv_chiptod_type_info);
type_register_static(&pnv_chiptod_power9_type_info);
type_register_static(&pnv_chiptod_power10_type_info);
}
type_init(pnv_chiptod_register_types);
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