core/pldm: Encode GetTID response

A PLDM Terminus is defined as the point of communication termination for
PLDM messages and the PLDM functions associated with those messages.
Given a PLDM terminus, a mechanism is required that can uniquely identify
each terminus so that the semantic information can be bound to that
identification.
The Terminus ID (TID) is a value that identifies a PLDM terminus.
TIDs are used in PLDM messages when it is necessary to identify the PLDM
terminus that is the source of the PLDM Message.

The GetTID command is used to retrieve the present Terminus ID (TID)
setting for a PLDM Terminus.

Reviewed-by: Abhishek Singh Tomar <abhishek@linux.ibm.com>
Signed-off-by: Christophe Lombard <clombard@linux.ibm.com>
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>

2 files changed, 68 insertions, 0 deletions

diff --git a/core/pldm/pldm-responder.c b/core/pldm/pldm-responder.c
index 74376f1..061b5c3 100644
--- a/core/pldm/pldm-responder.c
+++ b/core/pldm/pldm-responder.c
@@ -105,6 +105,17 @@ static void add_type(struct pldm_type *new_type)
 	      new_type->name, new_type->pldm_type_id);
 }
 
+static void add_cmd(struct pldm_type *type, struct pldm_cmd *new_cmd)
+{
+	assert(new_cmd->pldm_cmd_id < 256); /* limited by GetPLDMCommands */
+	assert(new_cmd->handler);
+	assert(!find_cmd(type, new_cmd->pldm_cmd_id));
+
+	list_add_tail(&type->commands, &new_cmd->link);
+	prlog(PR_DEBUG, "Registered command %s (%d) under %s\n",
+		new_cmd->name, new_cmd->pldm_cmd_id, type->name);
+}
+
 /*
  * PLDM Base commands support
  */
@@ -114,6 +125,54 @@ static struct pldm_type pldm_base_type = {
 	.version = { 0xF1, 0xF0, 0xF0, 0x00 },
 };
 
+/*
+ * GetTID command (0x02)
+ * The GetTID command is used to retrieve the present Terminus ID (TID)
+ * setting for a PLDM Terminus.
+ */
+static int base_get_tid_handler(const struct pldm_rx_data *rx)
+{
+	size_t data_size = PLDM_MSG_SIZE(struct pldm_get_tid_resp);
+	struct pldm_tx_data *tx;
+	int rc;
+
+	/* create a PLDM response message for GetTID */
+	tx = zalloc(sizeof(struct pldm_tx_data) + data_size);
+	if (!tx)
+		return OPAL_NO_MEM;
+	tx->data_size = data_size;
+	tx->tag_owner = true;
+	tx->msg_tag = rx->msg_tag;
+
+	rc = encode_get_tid_resp(rx->hdrinf.instance,
+				 PLDM_SUCCESS,
+				 HOST_TID,
+				 (struct pldm_msg *)tx->data);
+	if (rc != PLDM_SUCCESS) {
+		prlog(PR_ERR, "Encode GetTID Error, rc: %d\n", rc);
+		cc_resp(rx, rx->hdrinf.pldm_type,
+			rx->hdrinf.command, PLDM_ERROR);
+		free(tx);
+		return OPAL_PARAMETER;
+	}
+
+	rc = pldm_mctp_message_tx(tx);
+	if (rc) {
+		prlog(PR_ERR, "Failed to send GetTID response, rc = %d\n", rc);
+		free(tx);
+		return OPAL_HARDWARE;
+	}
+
+	free(tx);
+	return OPAL_SUCCESS;
+}
+
+static struct pldm_cmd pldm_base_get_tid = {
+	.name = "PLDM_GET_TID",
+	.pldm_cmd_id = PLDM_GET_TID,
+	.handler = base_get_tid_handler,
+};
+
 int pldm_responder_handle_request(struct pldm_rx_data *rx)
 {
 	const struct pldm_type *type;
@@ -149,6 +208,7 @@ int pldm_responder_init(void)
 {
 	/* Register mandatory commands we'll respond to - DSP0240 */
 	add_type(&pldm_base_type);
+	add_cmd(&pldm_base_type, &pldm_base_get_tid);
 
 	return OPAL_SUCCESS;
 }
diff --git a/include/ast.h b/include/ast.h
index 79efe4f..71237fb 100644
--- a/include/ast.h
+++ b/include/ast.h
@@ -101,6 +101,14 @@ void ast_setup_sio_mbox(uint16_t io_base, uint8_t irq);
 #define BMC_EID  8
 #define HOST_EID 9
 
+/*
+ * Skiboot's PLDM Terminus ID.
+ * BMC TID is 1, HB is 2, Skiboot is 3.
+ */
+#define BMC_TID  1
+#define HB_TID   2
+#define HOST_TID 3
+
 enum mctp_msg_type {
 	MCTP_MSG_TYPE_CONTROL = 0x00,
 	MCTP_MSG_TYPE_PLDM    = 0x01,