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 000000000..1b9e8347a
--- /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 "hw/sysbus.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qemu/log.h"
+#include "qemu/guest-random.h"
+#include "qemu/module.h"
+#include "qom/object.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"
+OBJECT_DECLARE_SIMPLE_TYPE(Exynos4210RngState, 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
+
+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;
+};
+
+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;
+
+    /* 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 */
+    if (qemu_guest_getrandom(s->randr_value, sizeof(s->randr_value), &err)) {
+        error_report_err(err);
+    } else {
+        /* Notify that PRNG is ready */
+        s->reg_status |= EXYNOS4210_RNG_STATUS_PRNG_DONE;
+    }
+
+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)