Re: [PATCH v2] hw/misc: i2c-echo: add tracing

[Corey Minyard <corey@minyard.net>]

On Tue, Jan 21, 2025 at 10:59:34AM +0000, Titus Rwantare wrote:
> This has been useful when debugging and unsure if the guest is
> generating i2c traffic.

Acked-by: Corey Minyard <cminyard@mvista.com>

> 
> Signed-off-by: Titus Rwantare <titusr@google.com>
> ---
>  hw/misc/i2c-echo.c   | 8 ++++++++
>  hw/misc/trace-events | 5 +++++
>  2 files changed, 13 insertions(+)
> 
> diff --git a/hw/misc/i2c-echo.c b/hw/misc/i2c-echo.c
> index 5ae3d0817e..65d10029dc 100644
> --- a/hw/misc/i2c-echo.c
> +++ b/hw/misc/i2c-echo.c
> @@ -13,6 +13,7 @@
>  #include "qemu/main-loop.h"
>  #include "block/aio.h"
>  #include "hw/i2c/i2c.h"
> +#include "trace.h"
>  
>  #define TYPE_I2C_ECHO "i2c-echo"
>  OBJECT_DECLARE_SIMPLE_TYPE(I2CEchoState, I2C_ECHO)
> @@ -80,11 +81,13 @@ static int i2c_echo_event(I2CSlave *s, enum i2c_event event)
>      case I2C_START_RECV:
>          state->pos = 0;
>  
> +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_RECV");
>          break;
>  
>      case I2C_START_SEND:
>          state->pos = 0;
>  
> +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_SEND");
>          break;
>  
>      case I2C_FINISH:
> @@ -92,12 +95,15 @@ static int i2c_echo_event(I2CSlave *s, enum i2c_event event)
>          state->state = I2C_ECHO_STATE_START_SEND;
>          i2c_bus_master(state->bus, state->bh);
>  
> +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_FINISH");
>          break;
>  
>      case I2C_NACK:
> +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_NACK");
>          break;
>  
>      default:
> +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "UNHANDLED");
>          return -1;
>      }
>  
> @@ -112,6 +118,7 @@ static uint8_t i2c_echo_recv(I2CSlave *s)
>          return 0xff;
>      }
>  
> +    trace_i2c_echo_recv(DEVICE(s)->canonical_path, state->data[state->pos]);
>      return state->data[state->pos++];
>  }
>  
> @@ -119,6 +126,7 @@ static int i2c_echo_send(I2CSlave *s, uint8_t data)
>  {
>      I2CEchoState *state = I2C_ECHO(s);
>  
> +    trace_i2c_echo_send(DEVICE(s)->canonical_path, data);
>      if (state->pos > 2) {
>          return -1;
>      }
> diff --git a/hw/misc/trace-events b/hw/misc/trace-events
> index cf1abe6928..d58dca2389 100644
> --- a/hw/misc/trace-events
> +++ b/hw/misc/trace-events
> @@ -390,3 +390,8 @@ ivshmem_flat_read_write_mmr_invalid(uint64_t addr_offset) "No ivshmem register m
>  ivshmem_flat_interrupt_invalid_peer(uint16_t peer_id) "Can't interrupt non-existing peer %u"
>  ivshmem_flat_write_mmr(uint64_t addr_offset) "Write access at offset %"PRIu64
>  ivshmem_flat_interrupt_peer(uint16_t peer_id, uint16_t vector_id) "Interrupting peer ID %u, vector %u..."
> +
> +#i2c-echo.c
> +i2c_echo_event(const char *id, const char *event) "%s: %s"
> +i2c_echo_recv(const char *id, uint8_t data) "%s: recv 0x%" PRIx8
> +i2c_echo_send(const char *id, uint8_t data) "%s: send 0x%" PRIx8
> -- 
> 2.48.0.rc2.279.g1de40edade-goog
>