hw/misc/nrf51_rng: Add NRF51 random number generator peripheral

Add a model of the NRF51 random number generator peripheral.
This is a simple random generator that continuously generates
new random values after startup.

Reference Manual: http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.pdf

Signed-off-by: Steffen Görtz <contrib@steffen-goertz.de>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190103091119.9367-4-stefanha@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 83 insertions, 0 deletions

diff --git a/include/hw/misc/nrf51_rng.h b/include/hw/misc/nrf51_rng.h
new file mode 100644
index 0000000000..3d6bf79997
--- /dev/null
+++ b/include/hw/misc/nrf51_rng.h
@@ -0,0 +1,83 @@
+/*
+ * nRF51 Random Number Generator
+ *
+ * QEMU interface:
+ * + Property "period_unfiltered_us": Time between two biased values in
+ *   microseconds.
+ * + Property "period_filtered_us": Time between two unbiased values in
+ *   microseconds.
+ * + sysbus MMIO regions 0: Memory Region with tasks, events and registers
+ *   to be mapped to the peripherals instance address by the SOC.
+ * + Named GPIO output "irq": Interrupt line of the peripheral. Must be
+ *   connected to the associated peripheral interrupt line of the NVIC.
+ * + Named GPIO output "eep_valrdy": Event set when new random value is ready
+ *   to be read.
+ * + Named GPIO input "tep_start": Task that triggers start of continuous
+ *   generation of random values.
+ * + Named GPIO input "tep_stop": Task that ends continuous generation of
+ *   random values.
+ *
+ * Accuracy of the peripheral model:
+ * + Stochastic properties of different configurations of the random source
+ *   are not modeled.
+ * + Generation of unfiltered and filtered random values take at least the
+ *   average generation time stated in the production specification;
+ *   non-deterministic generation times are not modeled.
+ *
+ * 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.
+ *
+ */
+#ifndef NRF51_RNG_H
+#define NRF51_RNG_H
+
+#include "hw/sysbus.h"
+#include "qemu/timer.h"
+#define TYPE_NRF51_RNG "nrf51_soc.rng"
+#define NRF51_RNG(obj) OBJECT_CHECK(NRF51RNGState, (obj), TYPE_NRF51_RNG)
+
+#define NRF51_RNG_SIZE         0x1000
+
+#define NRF51_RNG_TASK_START   0x000
+#define NRF51_RNG_TASK_STOP    0x004
+#define NRF51_RNG_EVENT_VALRDY 0x100
+#define NRF51_RNG_REG_SHORTS   0x200
+#define NRF51_RNG_REG_SHORTS_VALRDY_STOP 0
+#define NRF51_RNG_REG_INTEN    0x300
+#define NRF51_RNG_REG_INTEN_VALRDY 0
+#define NRF51_RNG_REG_INTENSET 0x304
+#define NRF51_RNG_REG_INTENCLR 0x308
+#define NRF51_RNG_REG_CONFIG   0x504
+#define NRF51_RNG_REG_CONFIG_DECEN 0
+#define NRF51_RNG_REG_VALUE    0x508
+
+typedef struct {
+    SysBusDevice parent_obj;
+
+    MemoryRegion mmio;
+    qemu_irq irq;
+
+    /* Event End Points */
+    qemu_irq eep_valrdy;
+
+    QEMUTimer timer;
+
+    /* Time between generation of successive unfiltered values in us */
+    uint16_t period_unfiltered_us;
+    /* Time between generation of successive filtered values in us */
+    uint16_t period_filtered_us;
+
+    uint8_t value;
+
+    uint32_t active;
+    uint32_t event_valrdy;
+    uint32_t shortcut_stop_on_valrdy;
+    uint32_t interrupt_enabled;
+    uint32_t filter_enabled;
+
+} NRF51RNGState;
+
+
+#endif /* NRF51_RNG_H_ */