On Tue, Jan 8, 2019 at 11:57 AM Peter Maydell <peter.mayd...@linaro.org> wrote:
> 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.
Sure, will send v2. It should also be hooked up by the microbit
machine type instead of being hardcoded into the nRF51 SoC.
Stefan
