On Sat, 5 Jan 2019 at 15:02, Stefan Hajnoczi <stefa...@redhat.com> wrote: > > From: Steffen Görtz <cont...@steffen-goertz.de> > > 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: Stefan Hajnoczi <stefa...@redhat.com> > Based-on: <20190103091119.9367-1-stefa...@redhat.com> > --- > Steffen: Please post your Signed-off-by. I did some minor cleanups so > your patch can be merged. Thanks! > > include/hw/arm/nrf51.h | 1 + > include/hw/arm/nrf51_soc.h | 1 + > hw/arm/nrf51_soc.c | 62 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 64 insertions(+)
> > +/* Two-Wire Interface (TWI) is not implemented but the microbit-dal firmware > + * panics if the TWI accelerometer and magnetometer WHO_AM_I registers cannot > + * be read. Stub out this read sequence so microbit-dal starts up. > + */ > +static uint32_t twi_read_sequence[] = {0x5A, 0x5A, 0x40}; > +static uint32_t twi_regs[0x1000 / 4]; > + > +static uint64_t twi_read(void *opaque, hwaddr addr, unsigned int size) > +{ > + static int i; > + 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[i]; > + if (i < ARRAY_SIZE(twi_read_sequence)) { > + i++; > + } > + break; > + default: > + data = twi_regs[addr / 4]; > + break; > + } > + > + qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx " [%u] = %" PRIx32 "\n", > + __func__, addr, size, (uint32_t)data); > + > + > + return data; > +} > + > +static void twi_write(void *opaque, hwaddr addr, uint64_t data, > + unsigned int size) > +{ > + qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx " <- 0x%" PRIx64 " > [%u]\n", > + __func__, addr, data, size); > + twi_regs[addr / 4] = data; > +} > + > +static const MemoryRegionOps twi_ops = { > + .read = twi_read, > + .write = twi_write > +}; Can you put this in its own device in its own source file, please? This is too much device-specific code to have in the SoC's source file. thanks -- PMM