Re: [Qemu-devel] [PATCH v2 2/2] tests/microbit-test: add TWI stub device test

[Thomas Huth <thuth@redhat.com>]

On 2019-01-10 10:40, Stefan Hajnoczi wrote:
> This test verifies that we read back the expected I2C WHO_AM_I register
> values for the accelerometer/magnetometer.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  tests/microbit-test.c | 44 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/tests/microbit-test.c b/tests/microbit-test.c
> index 0c125535f6..dcdc0cd41a 100644
> --- a/tests/microbit-test.c
> +++ b/tests/microbit-test.c
> @@ -21,6 +21,49 @@
>  #include "hw/arm/nrf51.h"
>  #include "hw/gpio/nrf51_gpio.h"
>  #include "hw/timer/nrf51_timer.h"
> +#include "hw/i2c/microbit_i2c.h"
> +
> +/* Read a byte from I2C device at @addr from register @reg */
> +static uint32_t i2c_read_byte(uint32_t addr, uint32_t reg)
> +{
> +    uint32_t val;
> +
> +    writel(NRF51_TWI_BASE + NRF51_TWI_REG_ADDRESS, addr);
> +    writel(NRF51_TWI_BASE + NRF51_TWI_TASK_STARTTX, 1);
> +    writel(NRF51_TWI_BASE + NRF51_TWI_REG_TXD, reg);
> +    val = readl(NRF51_TWI_BASE + NRF51_TWI_EVENT_TXDSENT);
> +    g_assert_cmpuint(val, ==, 1);
> +    writel(NRF51_TWI_BASE + NRF51_TWI_TASK_STOP, 1);
> +
> +    writel(NRF51_TWI_BASE + NRF51_TWI_TASK_STARTRX, 1);
> +    val = readl(NRF51_TWI_BASE + NRF51_TWI_EVENT_RXDREADY);
> +    g_assert_cmpuint(val, ==, 1);
> +    val = readl(NRF51_TWI_BASE + NRF51_TWI_REG_RXD);
> +    writel(NRF51_TWI_BASE + NRF51_TWI_TASK_STOP, 1);

Any chance that you could use qemu_writel() right from the start here?
That will make it easier to finally get rid of global_qtest one day...

 Thomas