diff options
Diffstat (limited to 'hw/i2c')
| -rw-r--r-- | hw/i2c/Makefile.objs | 1 | ||||
| -rw-r--r-- | hw/i2c/microbit_i2c.c | 127 |
2 files changed, 128 insertions, 0 deletions
diff --git a/hw/i2c/Makefile.objs b/hw/i2c/Makefile.objs index 37cacde978..82e747e1cd 100644 --- a/hw/i2c/Makefile.objs +++ b/hw/i2c/Makefile.objs @@ -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 diff --git a/hw/i2c/microbit_i2c.c b/hw/i2c/microbit_i2c.c new file mode 100644 index 0000000000..793f1b0f8b --- /dev/null +++ b/hw/i2c/microbit_i2c.c @@ -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), µbit_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 = µbit_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(µbit_i2c_info); +} + +type_init(microbit_i2c_register_types) |