[Skiboot] [PATCH 09/19] core/pldm: Implement PLDM requester

Christophe Lombard clombard at linux.vnet.ibm.com
Sat Feb 26 01:28:38 AEDT 2022


Implement a way for sending PLDM requests for specific PLDM commands.

Send a PLDM request message. Wait for corresponding response message,
which once received, is returned to the caller.

If there's data available, return success only if data is a PLDM response
message that matches instance, pldm_type and command code.

Signed-off-by: Christophe Lombard <clombard at linux.vnet.ibm.com>
---
 core/pldm/Makefile.inc     |   2 +-
 core/pldm/pldm-common.c    |   2 +
 core/pldm/pldm-requester.c | 268 +++++++++++++++++++++++++++++++++++++
 core/pldm/pldm.h           |   6 +
 4 files changed, 277 insertions(+), 1 deletion(-)
 create mode 100644 core/pldm/pldm-requester.c

diff --git a/core/pldm/Makefile.inc b/core/pldm/Makefile.inc
index 3909c86f..c431288f 100644
--- a/core/pldm/Makefile.inc
+++ b/core/pldm/Makefile.inc
@@ -7,7 +7,7 @@ SUBDIRS += $(PLDM_DIR)
 CPPFLAGS += -I$(SRC)/pldm/libpldm/
 CPPFLAGS += -I$(SRC)/pldm/ibm/libpldm/
 
-PLDM_OBJS = pldm-common.o pldm-responder.o
+PLDM_OBJS = pldm-common.o pldm-responder.o pldm-requester.o
 
 PLDM = $(PLDM_DIR)/built-in.a
 $(PLDM): $(PLDM_OBJS:%=$(PLDM_DIR)/%)
diff --git a/core/pldm/pldm-common.c b/core/pldm/pldm-common.c
index 76cb1aa5..15ee2af9 100644
--- a/core/pldm/pldm-common.c
+++ b/core/pldm/pldm-common.c
@@ -76,6 +76,8 @@ static int pldm_handle(uint8_t eid, const uint8_t *buf, int len)
 	}
 
 	switch (rx.hdrinf.msg_type) {
+	case PLDM_RESPONSE:
+		return pldm_rx_handle_response(&rx);
 	case PLDM_REQUEST:
 		return pldm_rx_handle_request(&rx);
 	break;
diff --git a/core/pldm/pldm-requester.c b/core/pldm/pldm-requester.c
new file mode 100644
index 00000000..47b61869
--- /dev/null
+++ b/core/pldm/pldm-requester.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+// Copyright 2022 IBM Corp.
+
+#define pr_fmt(fmt) "PLDM: " fmt
+
+#include <cpu.h>
+#include <stdio.h>
+#include <string.h>
+#include <timebase.h>
+#include <pldm/libpldm/utils.h>
+#include "pldm.h"
+
+struct pldm_request {
+	/* originating request params */
+	int dest;
+	int instance;
+	int cmd_code;
+	int type;
+
+	uint64_t timeout_ms;
+	uint64_t start_time;
+
+	void *buf;
+	int len;
+
+	/* completion callback */
+	void (*complete)(struct pldm_request *req,
+			 struct pldm_rx_data *resp);
+	void *cb_data;
+	int rc;
+
+	struct list_node link;
+};
+
+/*
+ * Sent out and waiting on a response.
+ */
+static struct pldm_request *active_request;
+
+static bool matches_request(const struct pldm_rx_data *rx,
+			    const struct pldm_request *req)
+{
+	if (req->instance != rx->hdrinf.instance)
+		return false;
+	if (req->type != rx->hdrinf.pldm_type)
+		return false;
+	if (req->cmd_code != rx->hdrinf.command)
+		return false;
+
+	return true;
+}
+
+/*
+ * Requests that are ready to send.
+ */
+LIST_HEAD(pldm_request_queue);
+
+static bool request_timed_out(struct pldm_request *req)
+{
+	uint64_t deadline = req->start_time + msecs_to_tb(req->timeout_ms);
+
+	return tb_compare(mftb(), deadline) == TB_AAFTERB;
+}
+
+/*
+ * Send the PLDM request.
+ */
+static void start_req(struct pldm_request *r)
+{
+	if (active_request) {
+		prlog(PR_ERR, "%s: request already active?\n",
+			      __func__);
+		return;
+	}
+
+	r->start_time = mftb();
+	active_request = r;
+
+	pldm_send(r->buf, r->len);
+}
+
+static void complete_request(struct pldm_rx_data *rx)
+{
+	struct pldm_request *req = active_request;
+
+	if (req->complete)
+		req->complete(req, rx);
+
+	active_request = NULL;
+}
+
+/*
+ * Add PLDM request in the queue/
+ */
+static int queue_request(int dest_eid, void *buf, int len,
+			 uint64_t timeout_ms,
+			 void (*complete)(struct pldm_request *,
+					  struct pldm_rx_data *),
+			 void *cb_data)
+{
+	struct pldm_header_info hdrinf;
+	struct pldm_request *pending;
+
+	if (active_request)
+		return OPAL_BUSY;
+
+	if (unpack_pldm_header(buf, &hdrinf)) {
+		prlog(PR_ERR, "%s: error parsing pldm header\n",
+			      __func__);
+		return OPAL_PARAMETER;
+	}
+
+	pending = zalloc(sizeof(struct pldm_request));
+
+	pending->dest		= dest_eid;
+	pending->instance	= hdrinf.instance;
+	pending->type		= hdrinf.pldm_type;
+	pending->cmd_code	= hdrinf.command;
+	pending->timeout_ms	= timeout_ms;
+
+	pending->buf		= buf;
+	pending->len		= len;
+
+	pending->complete	= complete;
+	pending->cb_data	= cb_data;
+
+	start_req(pending);
+
+	return OPAL_SUCCESS;
+}
+
+/*
+ * Synchronus request handling.
+ */
+struct pldm_do_request_data {
+	void **buf;
+	size_t *len;
+	bool done;
+	int rc;
+};
+
+static void do_request_cb(struct pldm_request *req,
+			  struct pldm_rx_data *resp)
+{
+	struct pldm_do_request_data *cb_data = req->cb_data;
+	int len = resp->msg_len;
+
+	if (resp && !request_timed_out(req)) {
+		*cb_data->len = len;
+		*cb_data->buf = malloc(len);
+		memcpy(*cb_data->buf, resp->msg, len);
+
+		cb_data->rc = OPAL_SUCCESS;
+	} else {
+		*cb_data->len = 0;
+		*cb_data->buf = NULL;
+		cb_data->rc = OPAL_TIMEOUT;
+	}
+
+	cb_data->done = true;
+
+	free(req);
+}
+
+/*
+ * Timeout :(
+ */
+static void pldm_timeout_cb(struct timer *t __unused, void *data,
+			    uint64_t now __unused)
+{
+	struct pldm_do_request_data *cb_data = data;
+
+	if (cb_data->done)
+		return;
+
+	prlog(PR_ERR, "%s, request timedout!\n", __func__);
+	complete_request(NULL);
+}
+
+/*
+ * Send a PLDM request and spin until we get a reply.
+ */
+int pldm_do_request(uint8_t dest_eid,
+		    void *request_msg, size_t request_len,
+		    void **response_msg, size_t *response_len)
+{
+	uint64_t now, queue_start, resp_start;
+	struct pldm_do_request_data cb_data;
+	struct timer pldm_timeout;
+	uint64_t timeout_ms;
+	int retries = 5;
+	int rc;
+
+	/* Start timer ton control a timeout from the PLDM terminus */
+	init_timer(&pldm_timeout, pldm_timeout_cb, &cb_data);
+	timeout_ms = 8000;
+
+	memset(&cb_data, 0, sizeof(cb_data));
+	cb_data.buf = response_msg;
+	cb_data.len = response_len;
+
+	/* Send PLDM request */
+	queue_start = mftb();
+	do {
+		rc = queue_request(dest_eid,
+				   request_msg, request_len,
+				   timeout_ms, do_request_cb,
+				   &cb_data);
+		if (rc == OPAL_BUSY) {
+			time_wait_ms(10);
+			retries--;
+		}
+		if (!retries) {
+			prlog(PR_ERR, "%s, timed out trying to queue "
+				      "PLDM request\n", __func__);
+			return OPAL_BUSY;
+		}
+	} while (rc == OPAL_BUSY);
+
+	if (rc) {
+		prlog(PR_ERR, "%s: Error %d while queuing request\n",
+			      __func__, rc);
+		return rc;
+	}
+
+	/* Wait for answer from the PLDM terminus */
+	schedule_timer(&pldm_timeout, msecs_to_tb(timeout_ms));
+	resp_start = mftb();
+	do {
+		time_wait_ms(5);
+	} while (!cb_data.done);
+
+	cancel_timer(&pldm_timeout);
+	now = mftb();
+
+	prlog(PR_TRACE, "%s: Finished after %ldms, length: %ld "
+			"(queuing: %ldms, resp: %ldms)\n",
+			__func__,
+			tb_to_msecs(now        - queue_start),
+			*cb_data.len,
+			tb_to_msecs(resp_start - queue_start),
+			tb_to_msecs(now        - resp_start));
+
+	return cb_data.rc;
+}
+
+/*
+ * Handle PLDM message received from the PLDM terminus over MCTP.
+ */
+int pldm_rx_handle_response(struct pldm_rx_data *rx)
+{
+	/* check the message received */
+	if (!matches_request(rx, active_request)) {
+		prlog(PR_ERR, "%s: Unexpected response! t:%d c:%d i:%d want %d,%d,%d\n",
+			__func__,
+			rx->hdrinf.pldm_type,
+			rx->hdrinf.command,
+			rx->hdrinf.instance,
+			active_request->type,
+			active_request->cmd_code,
+			active_request->instance
+			);
+		return OPAL_WRONG_STATE;
+	}
+
+	complete_request(rx);
+	return OPAL_SUCCESS;
+}
diff --git a/core/pldm/pldm.h b/core/pldm/pldm.h
index 74f883d6..fd677742 100644
--- a/core/pldm/pldm.h
+++ b/core/pldm/pldm.h
@@ -46,4 +46,10 @@ void pldm_rx_message(uint8_t eid, void *data __unused, void *vmsg,
 int pldm_rx_handle_request(struct pldm_rx_data *rx);
 int pldm_mctp_responder_init(void);
 
+/* Requester support */
+int pldm_do_request(uint8_t dest_eid,
+		    void *request_msg, size_t request_len,
+		    void **response_msg, size_t *response_len);
+int pldm_rx_handle_response(struct pldm_rx_data *rx);
+
 #endif /* __COREPLDM_H__ */
-- 
2.35.1



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