diff options
Diffstat (limited to 'hw/misc/exynos4210_rng.c')
| -rw-r--r-- | hw/misc/exynos4210_rng.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/hw/misc/exynos4210_rng.c b/hw/misc/exynos4210_rng.c new file mode 100644 index 0000000000..31ebe38e26 --- /dev/null +++ b/hw/misc/exynos4210_rng.c @@ -0,0 +1,277 @@ +/* + * Exynos4210 Pseudo Random Nubmer Generator Emulation + * + * Copyright (c) 2017 Krzysztof Kozlowski <krzk@kernel.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include "qemu/osdep.h" +#include "crypto/random.h" +#include "hw/sysbus.h" +#include "qemu/log.h" + +#define DEBUG_EXYNOS_RNG 0 + +#define DPRINTF(fmt, ...) \ + do { \ + if (DEBUG_EXYNOS_RNG) { \ + printf("exynos4210_rng: " fmt, ## __VA_ARGS__); \ + } \ + } while (0) + +#define TYPE_EXYNOS4210_RNG "exynos4210.rng" +#define EXYNOS4210_RNG(obj) \ + OBJECT_CHECK(Exynos4210RngState, (obj), TYPE_EXYNOS4210_RNG) + +/* + * Exynos4220, PRNG, only polling mode is supported. + */ + +/* RNG_CONTROL_1 register bitfields, reset value: 0x0 */ +#define EXYNOS4210_RNG_CONTROL_1_PRNG 0x8 +#define EXYNOS4210_RNG_CONTROL_1_START_INIT BIT(4) +/* RNG_STATUS register bitfields, reset value: 0x1 */ +#define EXYNOS4210_RNG_STATUS_PRNG_ERROR BIT(7) +#define EXYNOS4210_RNG_STATUS_PRNG_DONE BIT(5) +#define EXYNOS4210_RNG_STATUS_MSG_DONE BIT(4) +#define EXYNOS4210_RNG_STATUS_PARTIAL_DONE BIT(3) +#define EXYNOS4210_RNG_STATUS_PRNG_BUSY BIT(2) +#define EXYNOS4210_RNG_STATUS_SEED_SETTING_DONE BIT(1) +#define EXYNOS4210_RNG_STATUS_BUFFER_READY BIT(0) +#define EXYNOS4210_RNG_STATUS_WRITE_MASK (EXYNOS4210_RNG_STATUS_PRNG_DONE \ + | EXYNOS4210_RNG_STATUS_MSG_DONE \ + | EXYNOS4210_RNG_STATUS_PARTIAL_DONE) + +#define EXYNOS4210_RNG_CONTROL_1 0x0 +#define EXYNOS4210_RNG_STATUS 0x10 +#define EXYNOS4210_RNG_SEED_IN 0x140 +#define EXYNOS4210_RNG_SEED_IN_OFFSET(n) (EXYNOS4210_RNG_SEED_IN + (n * 0x4)) +#define EXYNOS4210_RNG_PRNG 0x160 +#define EXYNOS4210_RNG_PRNG_OFFSET(n) (EXYNOS4210_RNG_PRNG + (n * 0x4)) + +#define EXYNOS4210_RNG_PRNG_NUM 5 + +#define EXYNOS4210_RNG_REGS_MEM_SIZE 0x200 + +typedef struct Exynos4210RngState { + SysBusDevice parent_obj; + MemoryRegion iomem; + + int32_t randr_value[EXYNOS4210_RNG_PRNG_NUM]; + /* bits from 0 to EXYNOS4210_RNG_PRNG_NUM if given seed register was set */ + uint32_t seed_set; + + /* Register values */ + uint32_t reg_control; + uint32_t reg_status; +} Exynos4210RngState; + +static bool exynos4210_rng_seed_ready(const Exynos4210RngState *s) +{ + uint32_t mask = MAKE_64BIT_MASK(0, EXYNOS4210_RNG_PRNG_NUM); + + /* Return true if all the seed-set bits are set. */ + return (s->seed_set & mask) == mask; +} + +static void exynos4210_rng_set_seed(Exynos4210RngState *s, unsigned int i, + uint64_t val) +{ + /* + * We actually ignore the seed and always generate true random numbers. + * Theoretically this should not match the device as Exynos has + * a Pseudo Random Number Generator but testing shown that it always + * generates random numbers regardless of the seed value. + */ + s->seed_set |= BIT(i); + + /* If all seeds were written, update the status to reflect it */ + if (exynos4210_rng_seed_ready(s)) { + s->reg_status |= EXYNOS4210_RNG_STATUS_SEED_SETTING_DONE; + } else { + s->reg_status &= ~EXYNOS4210_RNG_STATUS_SEED_SETTING_DONE; + } +} + +static void exynos4210_rng_run_engine(Exynos4210RngState *s) +{ + Error *err = NULL; + int ret; + + /* Seed set? */ + if ((s->reg_status & EXYNOS4210_RNG_STATUS_SEED_SETTING_DONE) == 0) { + goto out; + } + + /* PRNG engine chosen? */ + if ((s->reg_control & EXYNOS4210_RNG_CONTROL_1_PRNG) == 0) { + goto out; + } + + /* PRNG engine started? */ + if ((s->reg_control & EXYNOS4210_RNG_CONTROL_1_START_INIT) == 0) { + goto out; + } + + /* Get randoms */ + ret = qcrypto_random_bytes((uint8_t *)s->randr_value, + sizeof(s->randr_value), &err); + if (!ret) { + /* Notify that PRNG is ready */ + s->reg_status |= EXYNOS4210_RNG_STATUS_PRNG_DONE; + } else { + error_report_err(err); + } + +out: + /* Always clear start engine bit */ + s->reg_control &= ~EXYNOS4210_RNG_CONTROL_1_START_INIT; +} + +static uint64_t exynos4210_rng_read(void *opaque, hwaddr offset, + unsigned size) +{ + Exynos4210RngState *s = (Exynos4210RngState *)opaque; + uint32_t val = 0; + + assert(size == 4); + + switch (offset) { + case EXYNOS4210_RNG_CONTROL_1: + val = s->reg_control; + break; + + case EXYNOS4210_RNG_STATUS: + val = s->reg_status; + break; + + case EXYNOS4210_RNG_PRNG_OFFSET(0): + case EXYNOS4210_RNG_PRNG_OFFSET(1): + case EXYNOS4210_RNG_PRNG_OFFSET(2): + case EXYNOS4210_RNG_PRNG_OFFSET(3): + case EXYNOS4210_RNG_PRNG_OFFSET(4): + val = s->randr_value[(offset - EXYNOS4210_RNG_PRNG_OFFSET(0)) / 4]; + DPRINTF("returning random @0x%" HWADDR_PRIx ": 0x%" PRIx32 "\n", + offset, val); + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: bad read offset 0x%" HWADDR_PRIx "\n", + __func__, offset); + } + + return val; +} + +static void exynos4210_rng_write(void *opaque, hwaddr offset, + uint64_t val, unsigned size) +{ + Exynos4210RngState *s = (Exynos4210RngState *)opaque; + + assert(size == 4); + + switch (offset) { + case EXYNOS4210_RNG_CONTROL_1: + DPRINTF("RNG_CONTROL_1 = 0x%" PRIx64 "\n", val); + s->reg_control = val; + exynos4210_rng_run_engine(s); + break; + + case EXYNOS4210_RNG_STATUS: + /* For clearing status fields */ + s->reg_status &= ~EXYNOS4210_RNG_STATUS_WRITE_MASK; + s->reg_status |= val & EXYNOS4210_RNG_STATUS_WRITE_MASK; + break; + + case EXYNOS4210_RNG_SEED_IN_OFFSET(0): + case EXYNOS4210_RNG_SEED_IN_OFFSET(1): + case EXYNOS4210_RNG_SEED_IN_OFFSET(2): + case EXYNOS4210_RNG_SEED_IN_OFFSET(3): + case EXYNOS4210_RNG_SEED_IN_OFFSET(4): + exynos4210_rng_set_seed(s, + (offset - EXYNOS4210_RNG_SEED_IN_OFFSET(0)) / 4, + val); + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: bad write offset 0x%" HWADDR_PRIx "\n", + __func__, offset); + } +} + +static const MemoryRegionOps exynos4210_rng_ops = { + .read = exynos4210_rng_read, + .write = exynos4210_rng_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static void exynos4210_rng_reset(DeviceState *dev) +{ + Exynos4210RngState *s = EXYNOS4210_RNG(dev); + + s->reg_control = 0; + s->reg_status = EXYNOS4210_RNG_STATUS_BUFFER_READY; + memset(s->randr_value, 0, sizeof(s->randr_value)); + s->seed_set = 0; +} + +static void exynos4210_rng_init(Object *obj) +{ + Exynos4210RngState *s = EXYNOS4210_RNG(obj); + SysBusDevice *dev = SYS_BUS_DEVICE(obj); + + memory_region_init_io(&s->iomem, obj, &exynos4210_rng_ops, s, + TYPE_EXYNOS4210_RNG, EXYNOS4210_RNG_REGS_MEM_SIZE); + sysbus_init_mmio(dev, &s->iomem); +} + +static const VMStateDescription exynos4210_rng_vmstate = { + .name = TYPE_EXYNOS4210_RNG, + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_INT32_ARRAY(randr_value, Exynos4210RngState, + EXYNOS4210_RNG_PRNG_NUM), + VMSTATE_UINT32(seed_set, Exynos4210RngState), + VMSTATE_UINT32(reg_status, Exynos4210RngState), + VMSTATE_UINT32(reg_control, Exynos4210RngState), + VMSTATE_END_OF_LIST() + } +}; + +static void exynos4210_rng_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = exynos4210_rng_reset; + dc->vmsd = &exynos4210_rng_vmstate; +} + +static const TypeInfo exynos4210_rng_info = { + .name = TYPE_EXYNOS4210_RNG, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(Exynos4210RngState), + .instance_init = exynos4210_rng_init, + .class_init = exynos4210_rng_class_init, +}; + +static void exynos4210_rng_register(void) +{ + type_register_static(&exynos4210_rng_info); +} + +type_init(exynos4210_rng_register) |