[PATCH v2 2/5] firmware: arm_scmi: Add helper to trace bad messages

From: Cristian Marussi
Date: Mon Mar 25 2024 - 16:51:12 EST


Upon reception of malformed and unexpected timed-out SCMI messages, it is
not possible to trace those bad messages in their entirety, because usually
we cannot even retrieve the payload, or it is just not reliable.

Add a helper to trace at least the content of the header of the received
message while associating a meaningful tag and error code.

Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
---
drivers/firmware/arm_scmi/common.h | 11 +++++++++
drivers/firmware/arm_scmi/driver.c | 39 ++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 6affbfdd1dec..b5ac25dbc1ca 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -301,6 +301,17 @@ extern const struct scmi_desc scmi_optee_desc;

void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv);

+enum scmi_bad_msg {
+ MSG_UNEXPECTED = -1,
+ MSG_INVALID = -2,
+ MSG_UNKNOWN = -3,
+ MSG_NOMEM = -4,
+ MSG_MBOX_SPURIOUS = -5,
+};
+
+void scmi_bad_message_trace(struct scmi_chan_info *cinfo, u32 msg_hdr,
+ enum scmi_bad_msg err);
+
/* shmem related declarations */
struct scmi_shared_mem;

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 2709598f3008..7fc1c5b1a2a4 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -696,6 +696,45 @@ scmi_xfer_lookup_unlocked(struct scmi_xfers_info *minfo, u16 xfer_id)
return xfer ?: ERR_PTR(-EINVAL);
}

+/**
+ * scmi_bad_message_trace - A helper to trace weird messages
+ *
+ * @cinfo: A reference to the channel descriptor on which the message was
+ * received
+ * @msg_hdr: Message header to track
+ * @err: A specific error code used as a status value in traces.
+ *
+ * This helper can be used to trace any kind of weird, incomplete, unexpected,
+ * timed-out message that arrives and as such, can be traced only referring to
+ * the header content, since the payload is missing/unreliable.
+ */
+void scmi_bad_message_trace(struct scmi_chan_info *cinfo, u32 msg_hdr,
+ enum scmi_bad_msg err)
+{
+ char *tag;
+ struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+
+ switch (MSG_XTRACT_TYPE(msg_hdr)) {
+ case MSG_TYPE_COMMAND:
+ tag = "!RESP";
+ break;
+ case MSG_TYPE_DELAYED_RESP:
+ tag = "!DLYD";
+ break;
+ case MSG_TYPE_NOTIFICATION:
+ tag = "!NOTI";
+ break;
+ default:
+ tag = "!UNKN";
+ break;
+ }
+
+ trace_scmi_msg_dump(info->id, cinfo->id,
+ MSG_XTRACT_PROT_ID(msg_hdr),
+ MSG_XTRACT_ID(msg_hdr), tag,
+ MSG_XTRACT_TOKEN(msg_hdr), err, NULL, 0);
+}
+
/**
* scmi_msg_response_validate - Validate message type against state of related
* xfer
--
2.44.0