i2c,trace: Add I2C operation trace events

Add support for tracing I2C transactions performed by skiboot. This covers
both internally initiated I2C ops and those that requested by the kernel
via the OPAL API.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/core/i2c.c b/core/i2c.c
index fd93081..b4313d4 100644
--- a/core/i2c.c
+++ b/core/i2c.c
@@ -13,6 +13,7 @@
 #include <timebase.h>
 #include <processor.h>
 #include <timer.h>
+#include <trace.h>
 
 static LIST_HEAD(i2c_bus_list);
 
@@ -38,6 +39,34 @@ struct i2c_bus *i2c_find_bus_by_id(uint32_t opal_id)
 	return NULL;
 }
 
+static inline void i2c_trace_req(struct i2c_request *req, int rc)
+{
+	struct trace_i2c t;
+
+	memset(&t, 0, sizeof(t));
+
+	t.bus = req->bus->opal_id;
+	t.type = req->op | (req->offset_bytes << 4);
+	t.i2c_addr = req->dev_addr;
+	t.smbus_reg = req->offset & 0xffff; // FIXME: log whole offset
+	t.size = req->rw_len;
+	t.rc = rc;
+
+	/* FIXME: trace should not be a union... */
+	trace_add((void *)&t, TRACE_I2C, sizeof(t));
+}
+
+int64_t i2c_queue_req(struct i2c_request *req)
+{
+	int64_t ret = req->bus->queue_req(req);
+
+	i2c_trace_req(req, OPAL_ASYNC_COMPLETION);
+
+	if (!ret)
+		req->req_state = i2c_req_queued;
+	return ret;
+}
+
 static void opal_i2c_request_complete(int rc, struct i2c_request *req)
 {
 	uint64_t token = (uint64_t)(unsigned long)req->user_data;
@@ -45,6 +74,8 @@ static void opal_i2c_request_complete(int rc, struct i2c_request *req)
 	opal_queue_msg(OPAL_MSG_ASYNC_COMP, NULL, NULL,
 			cpu_to_be64(token),
 			cpu_to_be64(rc));
+	i2c_trace_req(req, rc);
+
 	free(req);
 }
 
@@ -177,6 +208,7 @@ int64_t i2c_request_sync(struct i2c_request *req)
 		req->req_state = i2c_req_new;
 	}
 
+	i2c_trace_req(req, rc);
 	count = 0;
 	for (i = 0; i < req->rw_len && count < sizeof(buf); i++) {
 		count += snprintf(buf+count, sizeof(buf)-count, "%02x",