This commit implements the True Random Number Generator for the MAX78000 Signed-off-by: Jackson Donaldson <jc...@duck.com> Reviewed-by: Peter Maydell <peter.mayd...@linaro.org> --- hw/arm/Kconfig | 1 + hw/misc/Kconfig | 3 + hw/misc/max78000_gcr.c | 6 ++ hw/misc/max78000_trng.c | 139 ++++++++++++++++++++++++++++++++ hw/misc/meson.build | 1 + include/hw/misc/max78000_gcr.h | 1 + include/hw/misc/max78000_trng.h | 35 ++++++++ 7 files changed, 186 insertions(+) create mode 100644 hw/misc/max78000_trng.c create mode 100644 include/hw/misc/max78000_trng.h
diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig index 41bb64458f..fcac62be6f 100644 --- a/hw/arm/Kconfig +++ b/hw/arm/Kconfig @@ -369,6 +369,7 @@ config MAX78000_SOC select MAX78000_ICC select MAX78000_UART select MAX78000_GCR + select MAX78000_TRNG config RASPI bool diff --git a/hw/misc/Kconfig b/hw/misc/Kconfig index fde2266b8f..dd6a6e54da 100644 --- a/hw/misc/Kconfig +++ b/hw/misc/Kconfig @@ -53,6 +53,9 @@ config MAX78000_GCR config MAX78000_ICC bool +config MAX78000_TRNG + bool + config MOS6522 bool diff --git a/hw/misc/max78000_gcr.c b/hw/misc/max78000_gcr.c index 8c282f3916..5916ee615a 100644 --- a/hw/misc/max78000_gcr.c +++ b/hw/misc/max78000_gcr.c @@ -14,6 +14,7 @@ #include "migration/vmstate.h" #include "hw/qdev-properties.h" #include "hw/char/max78000_uart.h" +#include "hw/misc/max78000_trng.h" #include "hw/misc/max78000_gcr.h" @@ -157,6 +158,9 @@ static void max78000_gcr_write(void *opaque, hwaddr addr, if (val & UART0_RESET) { device_cold_reset(s->uart0); } + if (val & TRNG_RESET) { + device_cold_reset(s->trng); + } /* TODO: As other devices are implemented, add them here */ break; @@ -257,6 +261,8 @@ static const Property max78000_gcr_properties[] = { TYPE_MAX78000_UART, DeviceState*), DEFINE_PROP_LINK("uart2", Max78000GcrState, uart2, TYPE_MAX78000_UART, DeviceState*), + DEFINE_PROP_LINK("trng", Max78000GcrState, trng, + TYPE_MAX78000_TRNG, DeviceState*), }; static const MemoryRegionOps max78000_gcr_ops = { diff --git a/hw/misc/max78000_trng.c b/hw/misc/max78000_trng.c new file mode 100644 index 0000000000..ecdaef53b6 --- /dev/null +++ b/hw/misc/max78000_trng.c @@ -0,0 +1,139 @@ +/* + * MAX78000 True Random Number Generator + * + * Copyright (c) 2025 Jackson Donaldson <jc...@duck.com> + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "qemu/log.h" +#include "trace.h" +#include "hw/irq.h" +#include "migration/vmstate.h" +#include "hw/misc/max78000_trng.h" +#include "qemu/guest-random.h" + +static uint64_t max78000_trng_read(void *opaque, hwaddr addr, + unsigned int size) +{ + uint32_t data; + + Max78000TrngState *s = opaque; + switch (addr) { + case CTRL: + return s->ctrl; + + case STATUS: + return 1; + + case DATA: + /* + * When interrupts are enabled, reading random data should cause a + * new interrupt to be generated; since there's always a random number + * available, we could qemu_set_irq(s->irq, s->ctrl & RND_IE). Because + * of how trng_write is set up, this is always a noop, so don't + */ + qemu_guest_getrandom_nofail(&data, sizeof(data)); + return data; + + default: + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" + HWADDR_PRIx "\n", __func__, addr); + break; + } + return 0; +} + +static void max78000_trng_write(void *opaque, hwaddr addr, + uint64_t val64, unsigned int size) +{ + Max78000TrngState *s = opaque; + uint32_t val = val64; + switch (addr) { + case CTRL: + /* TODO: implement AES keygen */ + s->ctrl = val; + + /* + * This device models random number generation as taking 0 time. + * A new random number is always available, so the condition for the + * RND interrupt is always fulfilled; we can just set irq to 1. + */ + if (val & RND_IE) { + qemu_set_irq(s->irq, 1); + } else{ + qemu_set_irq(s->irq, 0); + } + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" + HWADDR_PRIx "\n", __func__, addr); + break; + } +} + +static void max78000_trng_reset_hold(Object *obj, ResetType type) +{ + Max78000TrngState *s = MAX78000_TRNG(obj); + s->ctrl = 0; + s->status = 0; + s->data = 0; +} + +static const MemoryRegionOps max78000_trng_ops = { + .read = max78000_trng_read, + .write = max78000_trng_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .valid.min_access_size = 4, + .valid.max_access_size = 4, +}; + +static const VMStateDescription max78000_trng_vmstate = { + .name = TYPE_MAX78000_TRNG, + .version_id = 1, + .minimum_version_id = 1, + .fields = (const VMStateField[]) { + VMSTATE_UINT32(ctrl, Max78000TrngState), + VMSTATE_UINT32(status, Max78000TrngState), + VMSTATE_UINT32(data, Max78000TrngState), + VMSTATE_END_OF_LIST() + } +}; + +static void max78000_trng_init(Object *obj) +{ + Max78000TrngState *s = MAX78000_TRNG(obj); + sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq); + + memory_region_init_io(&s->mmio, obj, &max78000_trng_ops, s, + TYPE_MAX78000_TRNG, 0x1000); + sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio); + +} + +static void max78000_trng_class_init(ObjectClass *klass, const void *data) +{ + ResettableClass *rc = RESETTABLE_CLASS(klass); + DeviceClass *dc = DEVICE_CLASS(klass); + + rc->phases.hold = max78000_trng_reset_hold; + dc->vmsd = &max78000_trng_vmstate; + +} + +static const TypeInfo max78000_trng_info = { + .name = TYPE_MAX78000_TRNG, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(Max78000TrngState), + .instance_init = max78000_trng_init, + .class_init = max78000_trng_class_init, +}; + +static void max78000_trng_register_types(void) +{ + type_register_static(&max78000_trng_info); +} + +type_init(max78000_trng_register_types) diff --git a/hw/misc/meson.build b/hw/misc/meson.build index 283d06dad4..c7c57d924b 100644 --- a/hw/misc/meson.build +++ b/hw/misc/meson.build @@ -72,6 +72,7 @@ system_ss.add(when: 'CONFIG_IMX', if_true: files( )) system_ss.add(when: 'CONFIG_MAX78000_GCR', if_true: files('max78000_gcr.c')) system_ss.add(when: 'CONFIG_MAX78000_ICC', if_true: files('max78000_icc.c')) +system_ss.add(when: 'CONFIG_MAX78000_TRNG', if_true: files('max78000_trng.c')) system_ss.add(when: 'CONFIG_NPCM7XX', if_true: files( 'npcm_clk.c', 'npcm_gcr.c', diff --git a/include/hw/misc/max78000_gcr.h b/include/hw/misc/max78000_gcr.h index f04c8a3ee7..23ddf0885b 100644 --- a/include/hw/misc/max78000_gcr.h +++ b/include/hw/misc/max78000_gcr.h @@ -123,6 +123,7 @@ struct Max78000GcrState { DeviceState *uart0; DeviceState *uart1; DeviceState *uart2; + DeviceState *trng; }; diff --git a/include/hw/misc/max78000_trng.h b/include/hw/misc/max78000_trng.h new file mode 100644 index 0000000000..c5a8129b6a --- /dev/null +++ b/include/hw/misc/max78000_trng.h @@ -0,0 +1,35 @@ +/* + * MAX78000 True Random Number Generator + * + * Copyright (c) 2025 Jackson Donaldson <jc...@duck.com> + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ +#ifndef HW_MAX78000_TRNG_H +#define HW_MAX78000_TRNG_H + +#include "hw/sysbus.h" +#include "qom/object.h" + +#define TYPE_MAX78000_TRNG "max78000-trng" +OBJECT_DECLARE_SIMPLE_TYPE(Max78000TrngState, MAX78000_TRNG) + +#define CTRL 0 +#define STATUS 4 +#define DATA 8 + +#define RND_IE (1 << 1) + +struct Max78000TrngState { + SysBusDevice parent_obj; + + MemoryRegion mmio; + + uint32_t ctrl; + uint32_t status; + uint32_t data; + + qemu_irq irq; +}; + +#endif -- 2.34.1