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

[Strahinja Jankovic]

On Mon, Feb 20, 2023 at 9:13 AM <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>
> ---
>  hw/i2c/allwinner-i2c.c         | 26 ++++++++++++++++++++++++--
>  include/hw/i2c/allwinner-i2c.h |  6 ++++++
>  2 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/hw/i2c/allwinner-i2c.c b/hw/i2c/allwinner-i2c.c
> index fa650e7e02..819638d740 100644
> --- a/hw/i2c/allwinner-i2c.c
> +++ b/hw/i2c/allwinner-i2c.c
> @@ -463,10 +463,16 @@ static void allwinner_i2c_write(void *opaque, hwaddr 
> offset,
>                  s->stat = STAT_FROM_STA(STAT_IDLE);
>                  s->cntr &= ~TWI_CNTR_M_STP;
>              }
> -            if ((s->cntr & TWI_CNTR_INT_FLAG) == 0) {
> -                /* Interrupt flag cleared */
> +
> +            if (!s->irq_clear_inverted && !(s->cntr & TWI_CNTR_INT_FLAG)) {
> +                /* Write 0 to clear this flag */
> +                qemu_irq_lower(s->irq);
> +            } else if (s->irq_clear_inverted && (s->cntr & 
> TWI_CNTR_INT_FLAG)) {
> +                /* Write 1 to clear this flag */
> +                s->cntr &= ~TWI_CNTR_INT_FLAG;
>                  qemu_irq_lower(s->irq);
>              }
> +
>              if ((s->cntr & TWI_CNTR_A_ACK) == 0) {
>                  if (STAT_TO_STA(s->stat) == STAT_M_DATA_RX_ACK) {
>                      s->stat = STAT_FROM_STA(STAT_M_DATA_RX_NACK);
> @@ -557,9 +563,25 @@ static const TypeInfo allwinner_i2c_type_info = {
>      .class_init = allwinner_i2c_class_init,
>  };
>
> +static void allwinner_i2c_sun6i_init(Object *obj)
> +{
> +    AWI2CState *s = AW_I2C(obj);
> +
> +    s->irq_clear_inverted = true;
> +}
> +
> +static const TypeInfo allwinner_i2c_sun6i_type_info = {
> +    .name = TYPE_AW_I2C_SUN6I,
> +    .parent = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(AWI2CState),
> +    .instance_init = allwinner_i2c_sun6i_init,
> +    .class_init = allwinner_i2c_class_init,
> +};
> +
>  static void allwinner_i2c_register_types(void)
>  {
>      type_register_static(&allwinner_i2c_type_info);
> +    type_register_static(&allwinner_i2c_sun6i_type_info);
>  }
>
>  type_init(allwinner_i2c_register_types)
> diff --git a/include/hw/i2c/allwinner-i2c.h b/include/hw/i2c/allwinner-i2c.h
> index 4f378b86ba..0e325d265e 100644
> --- a/include/hw/i2c/allwinner-i2c.h
> +++ b/include/hw/i2c/allwinner-i2c.h
> @@ -28,6 +28,10 @@
>  #include "qom/object.h"
>
>  #define TYPE_AW_I2C "allwinner.i2c"
> +
> +/** Allwinner I2C sun6i family and newer (A31, H2+, H3, etc) */
> +#define TYPE_AW_I2C_SUN6I    TYPE_AW_I2C "-sun6i"
> +
>  OBJECT_DECLARE_SIMPLE_TYPE(AWI2CState, AW_I2C)
>
>  #define AW_I2C_MEM_SIZE         0x24
> @@ -50,6 +54,8 @@ struct AWI2CState {
>      uint8_t srst;
>      uint8_t efr;
>      uint8_t lcr;
> +
> +    bool irq_clear_inverted;
>  };
>
>  #endif /* ALLWINNER_I2C_H */
> --
> 2.25.1
>

Tried this patch with avocado for cubieboard and orangepi-pc, all
tests are passing.

So for me:

Reviewed-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
Tested-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>