diff options
Diffstat (limited to 'hw/misc/nrf51_rng.c')
| -rw-r--r-- | hw/misc/nrf51_rng.c | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/hw/misc/nrf51_rng.c b/hw/misc/nrf51_rng.c new file mode 100644 index 0000000000..d188f044f4 --- /dev/null +++ b/hw/misc/nrf51_rng.c @@ -0,0 +1,262 @@ +/* + * nRF51 Random Number Generator + * + * Reference Manual: http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.1.pdf + * + * Copyright 2018 Steffen Görtz <contrib@steffen-goertz.de> + * + * This code is licensed under the GPL version 2 or later. See + * the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/log.h" +#include "qapi/error.h" +#include "hw/arm/nrf51.h" +#include "hw/misc/nrf51_rng.h" +#include "crypto/random.h" + +static void update_irq(NRF51RNGState *s) +{ + bool irq = s->interrupt_enabled && s->event_valrdy; + qemu_set_irq(s->irq, irq); +} + +static uint64_t rng_read(void *opaque, hwaddr offset, unsigned int size) +{ + NRF51RNGState *s = NRF51_RNG(opaque); + uint64_t r = 0; + + switch (offset) { + case NRF51_RNG_EVENT_VALRDY: + r = s->event_valrdy; + break; + case NRF51_RNG_REG_SHORTS: + r = s->shortcut_stop_on_valrdy; + break; + case NRF51_RNG_REG_INTEN: + case NRF51_RNG_REG_INTENSET: + case NRF51_RNG_REG_INTENCLR: + r = s->interrupt_enabled; + break; + case NRF51_RNG_REG_CONFIG: + r = s->filter_enabled; + break; + case NRF51_RNG_REG_VALUE: + r = s->value; + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: bad read offset 0x%" HWADDR_PRIx "\n", + __func__, offset); + } + + return r; +} + +static int64_t calc_next_timeout(NRF51RNGState *s) +{ + int64_t timeout = qemu_clock_get_us(QEMU_CLOCK_VIRTUAL); + if (s->filter_enabled) { + timeout += s->period_filtered_us; + } else { + timeout += s->period_unfiltered_us; + } + + return timeout; +} + + +static void rng_update_timer(NRF51RNGState *s) +{ + if (s->active) { + timer_mod(&s->timer, calc_next_timeout(s)); + } else { + timer_del(&s->timer); + } +} + + +static void rng_write(void *opaque, hwaddr offset, + uint64_t value, unsigned int size) +{ + NRF51RNGState *s = NRF51_RNG(opaque); + + switch (offset) { + case NRF51_RNG_TASK_START: + if (value == NRF51_TRIGGER_TASK) { + s->active = 1; + rng_update_timer(s); + } + break; + case NRF51_RNG_TASK_STOP: + if (value == NRF51_TRIGGER_TASK) { + s->active = 0; + rng_update_timer(s); + } + break; + case NRF51_RNG_EVENT_VALRDY: + if (value == NRF51_EVENT_CLEAR) { + s->event_valrdy = 0; + } + break; + case NRF51_RNG_REG_SHORTS: + s->shortcut_stop_on_valrdy = + (value & BIT_MASK(NRF51_RNG_REG_SHORTS_VALRDY_STOP)) ? 1 : 0; + break; + case NRF51_RNG_REG_INTEN: + s->interrupt_enabled = + (value & BIT_MASK(NRF51_RNG_REG_INTEN_VALRDY)) ? 1 : 0; + break; + case NRF51_RNG_REG_INTENSET: + if (value & BIT_MASK(NRF51_RNG_REG_INTEN_VALRDY)) { + s->interrupt_enabled = 1; + } + break; + case NRF51_RNG_REG_INTENCLR: + if (value & BIT_MASK(NRF51_RNG_REG_INTEN_VALRDY)) { + s->interrupt_enabled = 0; + } + break; + case NRF51_RNG_REG_CONFIG: + s->filter_enabled = + (value & BIT_MASK(NRF51_RNG_REG_CONFIG_DECEN)) ? 1 : 0; + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: bad write offset 0x%" HWADDR_PRIx "\n", + __func__, offset); + } + + update_irq(s); +} + +static const MemoryRegionOps rng_ops = { + .read = rng_read, + .write = rng_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .impl.min_access_size = 4, + .impl.max_access_size = 4 +}; + +static void nrf51_rng_timer_expire(void *opaque) +{ + NRF51RNGState *s = NRF51_RNG(opaque); + + qcrypto_random_bytes(&s->value, 1, &error_abort); + + s->event_valrdy = 1; + qemu_set_irq(s->eep_valrdy, 1); + + if (s->shortcut_stop_on_valrdy) { + s->active = 0; + } + + rng_update_timer(s); + update_irq(s); +} + +static void nrf51_rng_tep_start(void *opaque, int n, int level) +{ + NRF51RNGState *s = NRF51_RNG(opaque); + + if (level) { + s->active = 1; + rng_update_timer(s); + } +} + +static void nrf51_rng_tep_stop(void *opaque, int n, int level) +{ + NRF51RNGState *s = NRF51_RNG(opaque); + + if (level) { + s->active = 0; + rng_update_timer(s); + } +} + + +static void nrf51_rng_init(Object *obj) +{ + NRF51RNGState *s = NRF51_RNG(obj); + SysBusDevice *sbd = SYS_BUS_DEVICE(obj); + + memory_region_init_io(&s->mmio, obj, &rng_ops, s, + TYPE_NRF51_RNG, NRF51_RNG_SIZE); + sysbus_init_mmio(sbd, &s->mmio); + + timer_init_us(&s->timer, QEMU_CLOCK_VIRTUAL, nrf51_rng_timer_expire, s); + + sysbus_init_irq(sbd, &s->irq); + + /* Tasks */ + qdev_init_gpio_in_named(DEVICE(s), nrf51_rng_tep_start, "tep_start", 1); + qdev_init_gpio_in_named(DEVICE(s), nrf51_rng_tep_stop, "tep_stop", 1); + + /* Events */ + qdev_init_gpio_out_named(DEVICE(s), &s->eep_valrdy, "eep_valrdy", 1); +} + +static void nrf51_rng_reset(DeviceState *dev) +{ + NRF51RNGState *s = NRF51_RNG(dev); + + s->value = 0; + s->active = 0; + s->event_valrdy = 0; + s->shortcut_stop_on_valrdy = 0; + s->interrupt_enabled = 0; + s->filter_enabled = 0; + + rng_update_timer(s); +} + + +static Property nrf51_rng_properties[] = { + DEFINE_PROP_UINT16("period_unfiltered_us", NRF51RNGState, + period_unfiltered_us, 167), + DEFINE_PROP_UINT16("period_filtered_us", NRF51RNGState, + period_filtered_us, 660), + DEFINE_PROP_END_OF_LIST(), +}; + +static const VMStateDescription vmstate_rng = { + .name = "nrf51_soc.rng", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT32(active, NRF51RNGState), + VMSTATE_UINT32(event_valrdy, NRF51RNGState), + VMSTATE_UINT32(shortcut_stop_on_valrdy, NRF51RNGState), + VMSTATE_UINT32(interrupt_enabled, NRF51RNGState), + VMSTATE_UINT32(filter_enabled, NRF51RNGState), + VMSTATE_END_OF_LIST() + } +}; + +static void nrf51_rng_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->props = nrf51_rng_properties; + dc->vmsd = &vmstate_rng; + dc->reset = nrf51_rng_reset; +} + +static const TypeInfo nrf51_rng_info = { + .name = TYPE_NRF51_RNG, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(NRF51RNGState), + .instance_init = nrf51_rng_init, + .class_init = nrf51_rng_class_init +}; + +static void nrf51_rng_register_types(void) +{ + type_register_static(&nrf51_rng_info); +} + +type_init(nrf51_rng_register_types) |