From 54a5ba13a9ffe7d25fc649b0fa9f8314734c8ccc Mon Sep 17 00:00:00 2001 From: Marcin Chojnacki Date: Tue, 28 Feb 2017 12:08:13 +0000 Subject: [PATCH] target-arm: Implement BCM2835 hardware RNG Recent vanilla Raspberry Pi kernels started to make use of the hardware random number generator in BCM2835 SoC. As a result, those kernels wouldn't work anymore under QEMU but rather just freeze during the boot process. This patch implements a trivial BCM2835 compatible RNG, and adds it as a peripheral to BCM2835 platform, which allows to boot a vanilla Raspberry Pi kernel under Qemu. Changes since v1: * Prevented guest from writing [31..20] bits in rng_status * Removed redundant minimum_version_id_old * Added field entries for the state * Changed realize function to reset Signed-off-by: Marcin Chojnacki Message-id: 20170210210857.47893-1-marcinch7@gmail.com Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/arm/bcm2835_peripherals.c | 15 ++++ hw/misc/Makefile.objs | 1 + hw/misc/bcm2835_rng.c | 124 +++++++++++++++++++++++++++ include/hw/arm/bcm2835_peripherals.h | 2 + include/hw/misc/bcm2835_rng.h | 27 ++++++ 5 files changed, 169 insertions(+) create mode 100644 hw/misc/bcm2835_rng.c create mode 100644 include/hw/misc/bcm2835_rng.h diff --git a/hw/arm/bcm2835_peripherals.c b/hw/arm/bcm2835_peripherals.c index 2e641a3989..9ed22d5bc8 100644 --- a/hw/arm/bcm2835_peripherals.c +++ b/hw/arm/bcm2835_peripherals.c @@ -86,6 +86,11 @@ static void bcm2835_peripherals_init(Object *obj) object_property_add_const_link(OBJECT(&s->property), "dma-mr", OBJECT(&s->gpu_bus_mr), &error_abort); + /* Random Number Generator */ + object_initialize(&s->rng, sizeof(s->rng), TYPE_BCM2835_RNG); + object_property_add_child(obj, "rng", OBJECT(&s->rng), NULL); + qdev_set_parent_bus(DEVICE(&s->rng), sysbus_get_default()); + /* Extended Mass Media Controller */ object_initialize(&s->sdhci, sizeof(s->sdhci), TYPE_SYSBUS_SDHCI); object_property_add_child(obj, "sdhci", OBJECT(&s->sdhci), NULL); @@ -226,6 +231,16 @@ static void bcm2835_peripherals_realize(DeviceState *dev, Error **errp) sysbus_connect_irq(SYS_BUS_DEVICE(&s->property), 0, qdev_get_gpio_in(DEVICE(&s->mboxes), MBOX_CHAN_PROPERTY)); + /* Random Number Generator */ + object_property_set_bool(OBJECT(&s->rng), true, "realized", &err); + if (err) { + error_propagate(errp, err); + return; + } + + memory_region_add_subregion(&s->peri_mr, RNG_OFFSET, + sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->rng), 0)); + /* Extended Mass Media Controller */ object_property_set_int(OBJECT(&s->sdhci), BCM2835_SDHC_CAPAREG, "capareg", &err); diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs index 898e4ccfb1..57a4406581 100644 --- a/hw/misc/Makefile.objs +++ b/hw/misc/Makefile.objs @@ -42,6 +42,7 @@ obj-$(CONFIG_OMAP) += omap_sdrc.o obj-$(CONFIG_OMAP) += omap_tap.o obj-$(CONFIG_RASPI) += bcm2835_mbox.o obj-$(CONFIG_RASPI) += bcm2835_property.o +obj-$(CONFIG_RASPI) += bcm2835_rng.o obj-$(CONFIG_SLAVIO) += slavio_misc.o obj-$(CONFIG_ZYNQ) += zynq_slcr.o obj-$(CONFIG_ZYNQ) += zynq-xadc.o diff --git a/hw/misc/bcm2835_rng.c b/hw/misc/bcm2835_rng.c new file mode 100644 index 0000000000..2242bc5eb5 --- /dev/null +++ b/hw/misc/bcm2835_rng.c @@ -0,0 +1,124 @@ +/* + * BCM2835 Random Number Generator emulation + * + * Copyright (C) 2017 Marcin Chojnacki + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/log.h" +#include "hw/misc/bcm2835_rng.h" + +static uint64_t bcm2835_rng_read(void *opaque, hwaddr offset, + unsigned size) +{ + BCM2835RngState *s = (BCM2835RngState *)opaque; + uint32_t res = 0; + + assert(size == 4); + + switch (offset) { + case 0x0: /* rng_ctrl */ + res = s->rng_ctrl; + break; + case 0x4: /* rng_status */ + res = s->rng_status | (1 << 24); + break; + case 0x8: /* rng_data */ + res = rand(); + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, + "bcm2835_rng_read: Bad offset %x\n", + (int)offset); + res = 0; + break; + } + + return res; +} + +static void bcm2835_rng_write(void *opaque, hwaddr offset, + uint64_t value, unsigned size) +{ + BCM2835RngState *s = (BCM2835RngState *)opaque; + + assert(size == 4); + + switch (offset) { + case 0x0: /* rng_ctrl */ + s->rng_ctrl = value; + break; + case 0x4: /* rng_status */ + /* we shouldn't let the guest write to bits [31..20] */ + s->rng_status &= ~0xFFFFF; /* clear 20 lower bits */ + s->rng_status |= value & 0xFFFFF; /* set them to new value */ + break; + + default: + qemu_log_mask(LOG_GUEST_ERROR, + "bcm2835_rng_write: Bad offset %x\n", + (int)offset); + break; + } +} + +static const MemoryRegionOps bcm2835_rng_ops = { + .read = bcm2835_rng_read, + .write = bcm2835_rng_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static const VMStateDescription vmstate_bcm2835_rng = { + .name = TYPE_BCM2835_RNG, + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT32(rng_ctrl, BCM2835RngState), + VMSTATE_UINT32(rng_status, BCM2835RngState), + VMSTATE_END_OF_LIST() + } +}; + +static void bcm2835_rng_init(Object *obj) +{ + BCM2835RngState *s = BCM2835_RNG(obj); + + memory_region_init_io(&s->iomem, obj, &bcm2835_rng_ops, s, + TYPE_BCM2835_RNG, 0x10); + sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem); +} + +static void bcm2835_rng_reset(DeviceState *dev) +{ + BCM2835RngState *s = BCM2835_RNG(dev); + + s->rng_ctrl = 0; + s->rng_status = 0; +} + +static void bcm2835_rng_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = bcm2835_rng_reset; + dc->vmsd = &vmstate_bcm2835_rng; +} + +static TypeInfo bcm2835_rng_info = { + .name = TYPE_BCM2835_RNG, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(BCM2835RngState), + .class_init = bcm2835_rng_class_init, + .instance_init = bcm2835_rng_init, +}; + +static void bcm2835_rng_register_types(void) +{ + type_register_static(&bcm2835_rng_info); +} + +type_init(bcm2835_rng_register_types) diff --git a/include/hw/arm/bcm2835_peripherals.h b/include/hw/arm/bcm2835_peripherals.h index e12ae3721a..31241c799d 100644 --- a/include/hw/arm/bcm2835_peripherals.h +++ b/include/hw/arm/bcm2835_peripherals.h @@ -19,6 +19,7 @@ #include "hw/dma/bcm2835_dma.h" #include "hw/intc/bcm2835_ic.h" #include "hw/misc/bcm2835_property.h" +#include "hw/misc/bcm2835_rng.h" #include "hw/misc/bcm2835_mbox.h" #include "hw/sd/sdhci.h" @@ -41,6 +42,7 @@ typedef struct BCM2835PeripheralState { BCM2835DMAState dma; BCM2835ICState ic; BCM2835PropertyState property; + BCM2835RngState rng; BCM2835MboxState mboxes; SDHCIState sdhci; } BCM2835PeripheralState; diff --git a/include/hw/misc/bcm2835_rng.h b/include/hw/misc/bcm2835_rng.h new file mode 100644 index 0000000000..41a531bce7 --- /dev/null +++ b/include/hw/misc/bcm2835_rng.h @@ -0,0 +1,27 @@ +/* + * BCM2835 Random Number Generator emulation + * + * Copyright (C) 2017 Marcin Chojnacki + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef BCM2835_RNG_H +#define BCM2835_RNG_H + +#include "hw/sysbus.h" + +#define TYPE_BCM2835_RNG "bcm2835-rng" +#define BCM2835_RNG(obj) \ + OBJECT_CHECK(BCM2835RngState, (obj), TYPE_BCM2835_RNG) + +typedef struct { + SysBusDevice busdev; + MemoryRegion iomem; + + uint32_t rng_ctrl; + uint32_t rng_status; +} BCM2835RngState; + +#endif