This has been useful when debugging when unsure if the guest is
generating i2c traffic.

Signed-off-by: Titus Rwantare <titusr@google.com>
---
 hw/misc/i2c-echo.c   | 13 +++++++++++++
 hw/misc/trace-events |  5 +++++
 2 files changed, 18 insertions(+)

diff --git a/hw/misc/i2c-echo.c b/hw/misc/i2c-echo.c
index 5ae3d0817e..06110e0f8e 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 +81,19 @@ 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_START_SEND_ASYNC:
+        state->pos = 0;
+
+        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_SEND_ASYNC");
         break;
 
     case I2C_FINISH:
@@ -92,9 +101,11 @@ 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:
@@ -112,6 +123,7 @@ 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 +131,7 @@ 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

Hi Titus,

On 21/1/25 11:36, Titus Rwantare wrote:
> This has been useful when debugging when unsure if the guest is
> generating i2c traffic.
> 
> Signed-off-by: Titus Rwantare <titusr@google.com>
> ---
>   hw/misc/i2c-echo.c   | 13 +++++++++++++
>   hw/misc/trace-events |  5 +++++
>   2 files changed, 18 insertions(+)
> 
> diff --git a/hw/misc/i2c-echo.c b/hw/misc/i2c-echo.c
> index 5ae3d0817e..06110e0f8e 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 +81,19 @@ 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_START_SEND_ASYNC:
> +        state->pos = 0;
> +
> +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_SEND_ASYNC");

This patch is doing a bit more that what it describes, since now
START_SEND_ASYNC returns 0x00 instead of 0xff (besides updating pos).

Please split as one patch per logical change.

Thanks!

Phil.

>           break;
>   
>       case I2C_FINISH:

On Tue, 21 Jan 2025 at 02:43, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>
> Hi Titus,
>
> On 21/1/25 11:36, Titus Rwantare wrote:
> > This has been useful when debugging when unsure if the guest is
> > generating i2c traffic.
> >
> > Signed-off-by: Titus Rwantare <titusr@google.com>
> > ---
> >   hw/misc/i2c-echo.c   | 13 +++++++++++++
> >   hw/misc/trace-events |  5 +++++
> >   2 files changed, 18 insertions(+)
> >
> > diff --git a/hw/misc/i2c-echo.c b/hw/misc/i2c-echo.c
> > index 5ae3d0817e..06110e0f8e 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 +81,19 @@ 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_START_SEND_ASYNC:
> > +        state->pos = 0;
> > +
> > +        trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_SEND_ASYNC");
>
> This patch is doing a bit more that what it describes, since now
> START_SEND_ASYNC returns 0x00 instead of 0xff (besides updating pos).
>
> Please split as one patch per logical change.
>
> Thanks!
>
> Phil.
>

I've removed the async case from the patch as it's not something that
has come up.
- Titus