On Wed, Sep 24, 2025 at 7:25 PM Djordje Todorovic
<[email protected]> wrote:
>
> Add RISC-V implementation of the Coherent Manager Global Control
> Register (CMGCR) device. It is based on the existing MIPS CMGCR
> implementation but adapted for RISC-V systems.
>
> The CMGCR device provides global system control for multi-core
> configurations in RISC-V systems.
>
> This is needed for the MIPS BOSTON AIA board.
>
> Signed-off-by: Chao-ying Fu <[email protected]>
> Signed-off-by: Djordje Todorovic <[email protected]>
> Reviewed-by: Daniel Henrique Barboza <[email protected]>
> ---
> hw/misc/Kconfig | 9 ++
> hw/misc/meson.build | 2 +
> hw/misc/riscv_cmgcr.c | 246 ++++++++++++++++++++++++++++++++++
> include/hw/misc/riscv_cmgcr.h | 50 +++++++
> 4 files changed, 307 insertions(+)
> create mode 100644 hw/misc/riscv_cmgcr.c
> create mode 100644 include/hw/misc/riscv_cmgcr.h
>
> diff --git a/hw/misc/Kconfig b/hw/misc/Kconfig
> index 4e35657468..c72927c3ff 100644
> --- a/hw/misc/Kconfig
> +++ b/hw/misc/Kconfig
> @@ -121,6 +121,15 @@ config MIPS_ITU
> bool
> depends on TCG
>
> +config RISCV_CMGCR
> + bool
> +
> +config MIPS_BOSTON_AIA
> + bool
> + default y
> + depends on RISCV64
> + select RISCV_CMGCR
> +
> config MPS2_FPGAIO
> bool
> select LED
> diff --git a/hw/misc/meson.build b/hw/misc/meson.build
> index b1d8d8e5d2..ef891e465b 100644
> --- a/hw/misc/meson.build
> +++ b/hw/misc/meson.build
> @@ -157,6 +157,8 @@ specific_ss.add(when: 'CONFIG_MAC_VIA', if_true:
> files('mac_via.c'))
> specific_ss.add(when: 'CONFIG_MIPS_CPS', if_true: files('mips_cmgcr.c',
> 'mips_cpc.c'))
> specific_ss.add(when: 'CONFIG_MIPS_ITU', if_true: files('mips_itu.c'))
>
> +specific_ss.add(when: 'CONFIG_RISCV_CMGCR', if_true: files('riscv_cmgcr.c'))
> +
> system_ss.add(when: 'CONFIG_SBSA_REF', if_true: files('sbsa_ec.c'))
>
> # HPPA devices
> diff --git a/hw/misc/riscv_cmgcr.c b/hw/misc/riscv_cmgcr.c
> new file mode 100644
> index 0000000000..cb8351a3bf
> --- /dev/null
> +++ b/hw/misc/riscv_cmgcr.c
> @@ -0,0 +1,246 @@
> +/*
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License. See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
> + * Authors: Sanjay Lal <[email protected]>
> + *
> + * Copyright (C) 2015 Imagination Technologies
> + *
> + * Copyright (C) 2025 MIPS
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
Can you link to a datasheet
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/log.h"
> +#include "qemu/module.h"
> +#include "qapi/error.h"
> +#include "hw/sysbus.h"
> +#include "migration/vmstate.h"
> +#include "hw/misc/riscv_cmgcr.h"
> +#include "hw/qdev-properties.h"
> +
> +#include "cpu.h"
> +
> +#define CM_RESET_VEC 0x1FC00000
> +#define GCR_ADDRSPACE_SZ 0x8000
> +
> +/* Offsets to register blocks */
> +#define RISCV_GCB_OFS 0x0000 /* Global Control Block */
> +#define RISCV_CLCB_OFS 0x2000 /* Core Control Block */
> +#define RISCV_CORE_REG_STRIDE 0x100 /* Stride between core-specific
> registers */
> +
> +/* Global Control Block Register Map */
> +#define GCR_CONFIG_OFS 0x0000
> +#define GCR_BASE_OFS 0x0008
> +#define GCR_REV_OFS 0x0030
> +#define GCR_CPC_STATUS_OFS 0x00F0
> +#define GCR_L2_CONFIG_OFS 0x0130
> +
> +/* GCR_L2_CONFIG register fields */
> +#define GCR_L2_CONFIG_BYPASS_SHF 20
> +#define GCR_L2_CONFIG_BYPASS_MSK ((0x1ULL) << GCR_L2_CONFIG_BYPASS_SHF)
> +
> +/* GCR_BASE register fields */
> +#define GCR_BASE_GCRBASE_MSK 0xffffffff8000ULL
> +
> +/* GCR_CPC_BASE register fields */
> +#define GCR_CPC_BASE_CPCEN_MSK 1
> +#define GCR_CPC_BASE_CPCBASE_MSK 0xFFFFFFFF8000ULL
> +#define GCR_CPC_BASE_MSK (GCR_CPC_BASE_CPCEN_MSK | GCR_CPC_BASE_CPCBASE_MSK)
> +
> +/* GCR_CL_RESETBASE_OFS register fields */
> +#define GCR_CL_RESET_BASE_RESETBASE_MSK 0xFFFFFFFFFFFFF000U
> +#define GCR_CL_RESET_BASE_MSK GCR_CL_RESET_BASE_RESETBASE_MSK
> +
> +static inline bool is_cpc_connected(RISCVGCRState *s)
> +{
> + return s->cpc_mr != NULL;
> +}
> +
> +static inline void update_cpc_base(RISCVGCRState *gcr, uint64_t val)
> +{
> + if (is_cpc_connected(gcr)) {
> + gcr->cpc_base = val & GCR_CPC_BASE_MSK;
> + memory_region_transaction_begin();
> + memory_region_set_address(gcr->cpc_mr,
> + gcr->cpc_base & GCR_CPC_BASE_CPCBASE_MSK);
> + memory_region_set_enabled(gcr->cpc_mr,
> + gcr->cpc_base & GCR_CPC_BASE_CPCEN_MSK);
> + memory_region_transaction_commit();
> + }
> +}
> +
> +static inline void update_gcr_base(RISCVGCRState *gcr, uint64_t val)
> +{
> + gcr->gcr_base = val & GCR_BASE_GCRBASE_MSK;
> + memory_region_set_address(&gcr->iomem, gcr->gcr_base);
> +
> + /*
> + * For boston-aia, cpc_base is set to gcr_base + 0x8001 to enable
> + * cpc automatically.
> + */
> + update_cpc_base(gcr, val + 0x8001);
Will this break with future boards?
Alistair
> +}
> +
> +/* Read GCR registers */
> +static uint64_t gcr_read(void *opaque, hwaddr addr, unsigned size)
> +{
> + RISCVGCRState *gcr = (RISCVGCRState *) opaque;
> +
> + switch (addr) {
> + /* Global Control Block Register */
> + case GCR_CONFIG_OFS:
> + /* Set PCORES to 0 */
> + return 0;
> + case GCR_BASE_OFS:
> + return gcr->gcr_base;
> + case GCR_REV_OFS:
> + return gcr->gcr_rev;
> + case GCR_CPC_STATUS_OFS:
> + return is_cpc_connected(gcr);
> + case GCR_L2_CONFIG_OFS:
> + /* L2 BYPASS */
> + return GCR_L2_CONFIG_BYPASS_MSK;
> + default:
> + qemu_log_mask(LOG_UNIMP, "Read %d bytes at GCR offset 0x%"
> HWADDR_PRIx
> + "\n", size, addr);
> + }
> + return 0;
> +}
> +
> +static inline target_ulong get_exception_base(RISCVGCRVPState *vps)
> +{
> + return vps->reset_base & GCR_CL_RESET_BASE_RESETBASE_MSK;
> +}
> +
> +/* Write GCR registers */
> +static void gcr_write(void *opaque, hwaddr addr, uint64_t data, unsigned
> size)
> +{
> + RISCVGCRState *gcr = (RISCVGCRState *)opaque;
> + RISCVGCRVPState *current_vps;
> + int cpu_index, c, h;
> +
> + for (c = 0; c < gcr->num_core; c++) {
> + for (h = 0; h < gcr->num_hart; h++) {
> + if (addr == RISCV_CLCB_OFS + c * RISCV_CORE_REG_STRIDE + h * 8) {
> + cpu_index = c * gcr->num_hart + h;
> + current_vps = &gcr->vps[cpu_index];
> + current_vps->reset_base = data & GCR_CL_RESET_BASE_MSK;
> + cpu_set_exception_base(cpu_index + gcr->cluster_id *
> + gcr->num_core * gcr->num_hart,
> + get_exception_base(current_vps));
> + return;
> + }
> + }
> + }
> +
> + switch (addr) {
> + case GCR_BASE_OFS:
> + update_gcr_base(gcr, data);
> + break;
> + default:
> + qemu_log_mask(LOG_UNIMP, "Write %d bytes at GCR offset 0x%"
> HWADDR_PRIx
> + " 0x%" PRIx64 "\n", size, addr, data);
> + break;
> + }
> +}
> +
> +static const MemoryRegionOps gcr_ops = {
> + .read = gcr_read,
> + .write = gcr_write,
> + .endianness = DEVICE_NATIVE_ENDIAN,
> + .impl = {
> + .max_access_size = 8,
> + },
> +};
> +
> +static void riscv_gcr_init(Object *obj)
> +{
> + SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
> + RISCVGCRState *s = RISCV_GCR(obj);
> +
> + memory_region_init_io(&s->iomem, OBJECT(s), &gcr_ops, s,
> + "riscv-gcr", GCR_ADDRSPACE_SZ);
> + sysbus_init_mmio(sbd, &s->iomem);
> +}
> +
> +static void riscv_gcr_reset(DeviceState *dev)
> +{
> + RISCVGCRState *s = RISCV_GCR(dev);
> + int i;
> +
> + /* Update cpc_base to gcr_base + 0x8001 to enable cpc automatically. */
> + update_cpc_base(s, s->gcr_base + 0x8001);
> +
> + for (i = 0; i < s->num_vps; i++) {
> + s->vps[i].reset_base = CM_RESET_VEC & GCR_CL_RESET_BASE_MSK;
> + cpu_set_exception_base(i, get_exception_base(&s->vps[i]));
> + }
> +}
> +
> +static const VMStateDescription vmstate_riscv_gcr = {
> + .name = "riscv-gcr",
> + .version_id = 0,
> + .minimum_version_id = 0,
> + .fields = (VMStateField[]) {
> + VMSTATE_UINT64(cpc_base, RISCVGCRState),
> + VMSTATE_END_OF_LIST()
> + },
> +};
> +
> +static const Property riscv_gcr_properties[] = {
> + DEFINE_PROP_UINT32("cluster-id", RISCVGCRState, cluster_id, 0),
> + DEFINE_PROP_UINT32("num-vp", RISCVGCRState, num_vps, 1),
> + DEFINE_PROP_UINT32("num-hart", RISCVGCRState, num_hart, 1),
> + DEFINE_PROP_UINT32("num-core", RISCVGCRState, num_core, 1),
> + DEFINE_PROP_INT32("gcr-rev", RISCVGCRState, gcr_rev, 0xa00),
> + DEFINE_PROP_UINT64("gcr-base", RISCVGCRState, gcr_base, GCR_BASE_ADDR),
> + DEFINE_PROP_LINK("cpc", RISCVGCRState, cpc_mr, TYPE_MEMORY_REGION,
> + MemoryRegion *),
> +};
> +
> +static void riscv_gcr_realize(DeviceState *dev, Error **errp)
> +{
> + RISCVGCRState *s = RISCV_GCR(dev);
> +
> + /* Validate num_vps */
> + if (s->num_vps == 0) {
> + error_setg(errp, "num-vp must be at least 1");
> + return;
> + }
> + if (s->num_vps > GCR_MAX_VPS) {
> + error_setg(errp, "num-vp cannot exceed %d", GCR_MAX_VPS);
> + return;
> + }
> +
> + /* Create local set of registers for each VP */
> + s->vps = g_new(RISCVGCRVPState, s->num_vps);
> +}
> +
> +static void riscv_gcr_class_init(ObjectClass *klass, const void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> + device_class_set_props(dc, riscv_gcr_properties);
> + dc->vmsd = &vmstate_riscv_gcr;
> + device_class_set_legacy_reset(dc, riscv_gcr_reset);
> + dc->realize = riscv_gcr_realize;
> +}
> +
> +static const TypeInfo riscv_gcr_info = {
> + .name = TYPE_RISCV_GCR,
> + .parent = TYPE_SYS_BUS_DEVICE,
> + .instance_size = sizeof(RISCVGCRState),
> + .instance_init = riscv_gcr_init,
> + .class_init = riscv_gcr_class_init,
> +};
> +
> +static void riscv_gcr_register_types(void)
> +{
> + type_register_static(&riscv_gcr_info);
> +}
> +
> +type_init(riscv_gcr_register_types)
> diff --git a/include/hw/misc/riscv_cmgcr.h b/include/hw/misc/riscv_cmgcr.h
> new file mode 100644
> index 0000000000..c57d4ada1c
> --- /dev/null
> +++ b/include/hw/misc/riscv_cmgcr.h
> @@ -0,0 +1,50 @@
> +/*
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License. See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Copyright (C) 2015 Imagination Technologies
> + *
> + * Copyright (C) 2025 MIPS
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + *
> + */
> +
> +#ifndef RISCV_CMGCR_H
> +#define RISCV_CMGCR_H
> +
> +#include "hw/sysbus.h"
> +#include "qom/object.h"
> +
> +#define TYPE_RISCV_GCR "riscv-gcr"
> +OBJECT_DECLARE_SIMPLE_TYPE(RISCVGCRState, RISCV_GCR)
> +
> +#define GCR_BASE_ADDR 0x1fb80000ULL
> +#define GCR_MAX_VPS 256
> +
> +typedef struct RISCVGCRVPState RISCVGCRVPState;
> +struct RISCVGCRVPState {
> + uint64_t reset_base;
> +};
> +
> +typedef struct RISCVGCRState RISCVGCRState;
> +struct RISCVGCRState {
> + SysBusDevice parent_obj;
> +
> + int32_t gcr_rev;
> + uint32_t cluster_id;
> + uint32_t num_vps;
> + uint32_t num_hart;
> + uint32_t num_core;
> + hwaddr gcr_base;
> + MemoryRegion iomem;
> + MemoryRegion *cpc_mr;
> +
> + uint64_t cpc_base;
> +
> + /* VP Local/Other Registers */
> + RISCVGCRVPState *vps;
> +};
> +
> +#endif /* RISCV_CMGCR_H */
> --
> 2.34.1
>
