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arm: Stub out NRF51 TWI magnetometer/accelerometer detection 

Recent microbit firmwares panic if the TWI magnetometer/accelerometer
devices are not detected during startup.  We don't implement TWI (I2C)
so let's stub out these devices just to let the firmware boot.

Signed-off by: Steffen Görtz <contrib@steffen-goertz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190110094020.18354-2-stefanha@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: fixed comment style]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Steffen Görtz 2019-01-29 11:46:03 +00:00 committed by Peter Maydell
parent ab65eed3f8
commit 9d68bf564e
6 changed files with 189 additions and 0 deletions
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16
hw/arm/microbit.c
View File

@ -16,11 +16,13 @@
#include "exec/address-spaces.h"
#include "hw/arm/nrf51_soc.h"
#include "hw/i2c/microbit_i2c.h"
typedef struct {
MachineState parent;
NRF51State nrf51;
MicrobitI2CState i2c;
} MicrobitMachineState;
#define TYPE_MICROBIT_MACHINE MACHINE_TYPE_NAME("microbit")
@ -32,7 +34,9 @@ static void microbit_init(MachineState *machine)
{
MicrobitMachineState *s = MICROBIT_MACHINE(machine);
MemoryRegion *system_memory = get_system_memory();
MemoryRegion *mr;
Object *soc = OBJECT(&s->nrf51);
Object *i2c = OBJECT(&s->i2c);
sysbus_init_child_obj(OBJECT(machine), "nrf51", soc, sizeof(s->nrf51),
TYPE_NRF51_SOC);
@ -41,6 +45,18 @@ static void microbit_init(MachineState *machine)
&error_fatal);
object_property_set_bool(soc, true, "realized", &error_fatal);
/*
* Overlap the TWI stub device into the SoC. This is a microbit-specific
* hack until we implement the nRF51 TWI controller properly and the
* magnetometer/accelerometer devices.
*/
sysbus_init_child_obj(OBJECT(machine), "microbit.twi", i2c,
sizeof(s->i2c), TYPE_MICROBIT_I2C);
object_property_set_bool(i2c, true, "realized", &error_fatal);
mr = sysbus_mmio_get_region(SYS_BUS_DEVICE(i2c), 0);
memory_region_add_subregion_overlap(&s->nrf51.container, NRF51_TWI_BASE,
mr, -1);
armv7m_load_kernel(ARM_CPU(first_cpu), machine->kernel_filename,
NRF51_SOC(soc)->flash_size);
}

1
hw/i2c/Makefile.objs
View File

@ -7,5 +7,6 @@ common-obj-$(CONFIG_BITBANG_I2C) += bitbang_i2c.o
common-obj-$(CONFIG_EXYNOS4) += exynos4210_i2c.o
common-obj-$(CONFIG_IMX_I2C) += imx_i2c.o
common-obj-$(CONFIG_ASPEED_SOC) += aspeed_i2c.o
common-obj-$(CONFIG_NRF51_SOC) += microbit_i2c.o
obj-$(CONFIG_OMAP) += omap_i2c.o
obj-$(CONFIG_PPC4XX) += ppc4xx_i2c.o

127
hw/i2c/microbit_i2c.c Normal file
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@ -0,0 +1,127 @@
/*
* Microbit stub for Nordic Semiconductor nRF51 SoC Two-Wire Interface
* http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.1.pdf
*
* This is a microbit-specific stub for the TWI controller on the nRF51 SoC.
* We don't emulate I2C devices but the firmware probes the
* accelerometer/magnetometer on startup and panics if they are not found.
* Therefore we stub out the probing.
*
* In the future this file could evolve into a full nRF51 TWI controller
* device.
*
* Copyright 2018 Steffen Görtz <contrib@steffen-goertz.de>
* Copyright 2019 Red Hat, Inc.
*
* 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 "hw/i2c/microbit_i2c.h"
static const uint32_t twi_read_sequence[] = {0x5A, 0x5A, 0x40};
static uint64_t microbit_i2c_read(void *opaque, hwaddr addr, unsigned int size)
{
MicrobitI2CState *s = opaque;
uint64_t data = 0x00;
switch (addr) {
case NRF51_TWI_EVENT_STOPPED:
data = 0x01;
break;
case NRF51_TWI_EVENT_RXDREADY:
data = 0x01;
break;
case NRF51_TWI_EVENT_TXDSENT:
data = 0x01;
break;
case NRF51_TWI_REG_RXD:
data = twi_read_sequence[s->read_idx];
if (s->read_idx < G_N_ELEMENTS(twi_read_sequence)) {
s->read_idx++;
}
break;
default:
data = s->regs[addr / sizeof(s->regs[0])];
break;
}
qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx " [%u] = %" PRIx32 "\n",
__func__, addr, size, (uint32_t)data);
return data;
}
static void microbit_i2c_write(void *opaque, hwaddr addr, uint64_t data,
unsigned int size)
{
MicrobitI2CState *s = opaque;
qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx " <- 0x%" PRIx64 " [%u]\n",
__func__, addr, data, size);
s->regs[addr / sizeof(s->regs[0])] = data;
}
static const MemoryRegionOps microbit_i2c_ops = {
.read = microbit_i2c_read,
.write = microbit_i2c_write,
.endianness = DEVICE_LITTLE_ENDIAN,
.impl.min_access_size = 4,
.impl.max_access_size = 4,
};
static const VMStateDescription microbit_i2c_vmstate = {
.name = TYPE_MICROBIT_I2C,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT32_ARRAY(regs, MicrobitI2CState, MICROBIT_I2C_NREGS),
VMSTATE_UINT32(read_idx, MicrobitI2CState),
},
};
static void microbit_i2c_reset(DeviceState *dev)
{
MicrobitI2CState *s = MICROBIT_I2C(dev);
memset(s->regs, 0, sizeof(s->regs));
s->read_idx = 0;
}
static void microbit_i2c_realize(DeviceState *dev, Error **errp)
{
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
MicrobitI2CState *s = MICROBIT_I2C(dev);
memory_region_init_io(&s->iomem, OBJECT(s), &microbit_i2c_ops, s,
"microbit.twi", NRF51_TWI_SIZE);
sysbus_init_mmio(sbd, &s->iomem);
}
static void microbit_i2c_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->vmsd = &microbit_i2c_vmstate;
dc->reset = microbit_i2c_reset;
dc->realize = microbit_i2c_realize;
dc->desc = "Microbit I2C controller";
}
static const TypeInfo microbit_i2c_info = {
.name = TYPE_MICROBIT_I2C,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(MicrobitI2CState),
.class_init = microbit_i2c_class_init,
};
static void microbit_i2c_register_types(void)
{
type_register_static(&microbit_i2c_info);
}
type_init(microbit_i2c_register_types)

2
include/hw/arm/nrf51.h
View File

@ -25,6 +25,8 @@
#define NRF51_IOMEM_SIZE 0x20000000
#define NRF51_UART_BASE 0x40002000
#define NRF51_TWI_BASE 0x40003000
#define NRF51_TWI_SIZE 0x00001000
#define NRF51_TIMER_BASE 0x40008000
#define NRF51_TIMER_SIZE 0x00001000
#define NRF51_RNG_BASE 0x4000D000

1
include/hw/arm/nrf51_soc.h
View File

@ -39,6 +39,7 @@ typedef struct NRF51State {
MemoryRegion sram;
MemoryRegion flash;
MemoryRegion clock;
MemoryRegion twi;
uint32_t sram_size;
uint32_t flash_size;

42
include/hw/i2c/microbit_i2c.h Normal file
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@ -0,0 +1,42 @@
/*
* Microbit stub for Nordic Semiconductor nRF51 SoC Two-Wire Interface
* http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.1.pdf
*
* Copyright 2019 Red Hat, Inc.
*
* This code is licensed under the GPL version 2 or later. See
* the COPYING file in the top-level directory.
*/
#ifndef MICROBIT_I2C_H
#define MICROBIT_I2C_H
#include "hw/sysbus.h"
#include "hw/arm/nrf51.h"
#define NRF51_TWI_TASK_STARTRX 0x000
#define NRF51_TWI_TASK_STARTTX 0x008
#define NRF51_TWI_TASK_STOP 0x014
#define NRF51_TWI_EVENT_STOPPED 0x104
#define NRF51_TWI_EVENT_RXDREADY 0x108
#define NRF51_TWI_EVENT_TXDSENT 0x11c
#define NRF51_TWI_REG_ENABLE 0x500
#define NRF51_TWI_REG_RXD 0x518
#define NRF51_TWI_REG_TXD 0x51c
#define NRF51_TWI_REG_ADDRESS 0x588
#define TYPE_MICROBIT_I2C "microbit.i2c"
#define MICROBIT_I2C(obj) \
OBJECT_CHECK(MicrobitI2CState, (obj), TYPE_MICROBIT_I2C)
#define MICROBIT_I2C_NREGS (NRF51_TWI_SIZE / sizeof(uint32_t))
typedef struct {
SysBusDevice parent_obj;
MemoryRegion iomem;
uint32_t regs[MICROBIT_I2C_NREGS];
uint32_t read_idx;
} MicrobitI2CState;
#endif /* MICROBIT_I2C_H */