Re: [PATCH v2 2/3] hw: allwinner-i2c: Fix TWI_CNTR_INT_FLAG on SUN6i SoCs

[Peter Maydell]

On Mon, 20 Feb 2023 at 08:13, <qianfanguijin@163.com> wrote:
>
> From: qianfan Zhao <qianfanguijin@163.com>
>
> TWI_CNTR_INT_FLAG is W1C(write 1 to clear and write 0 has non-effect)
> register on SUN6i based SoCs, we should lower interrupt when the guest
> set this bit.
>
> The linux kernel will hang in irq handler(mv64xxx_i2c_intr) if no
> device connected on the i2c bus, next is the trace log:
>
> allwinner_i2c_write write   CNTR(0x0c): 0xc4 A_ACK BUS_EN INT_EN
> allwinner_i2c_write write   CNTR(0x0c): 0xcc A_ACK INT_FLAG BUS_EN INT_EN
> allwinner_i2c_read  read    CNTR(0x0c): 0xcc A_ACK INT_FLAG BUS_EN INT_EN
> allwinner_i2c_read  read    STAT(0x10): 0x20 STAT_M_ADDR_WR_NACK
> allwinner_i2c_write write   CNTR(0x0c): 0x54 A_ACK M_STP BUS_EN
> allwinner_i2c_write write   CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
> allwinner_i2c_read  read    CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
> allwinner_i2c_read  read    STAT(0x10): 0xf8 STAT_IDLE
> allwinner_i2c_write write   CNTR(0x0c): 0x54 A_ACK M_STP BUS_EN
> allwinner_i2c_write write   CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
> allwinner_i2c_read  read    CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
> allwinner_i2c_read  read    STAT(0x10): 0xf8 STAT_IDLE
> ...
>
> Fix it.
>
> Signed-off-by: qianfan Zhao <qianfanguijin@163.com>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM