discover/platform-powerpc: Implement direct IPMI interface

This change adds a direct IPMI interface to the /dev/ipmi0 device node,
which is present on OpenPower machines.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 181 insertions, 1 deletions

diff --git a/discover/ipmi.c b/discover/ipmi.c
index b8f1830..710a47d 100644
--- a/discover/ipmi.c
+++ b/discover/ipmi.c
@@ -1,6 +1,28 @@
 
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <sys/types.h>
+
+#include <linux/ipmi.h>
+
+#include <log/log.h>
+#include <talloc/talloc.h>
+
 #include "ipmi.h"
 
+struct ipmi {
+	int	fd;
+	long	seq;
+};
+
+static const char *ipmi_devnode = "/dev/ipmi0";
+
 bool ipmi_bootdev_is_valid(int x)
 {
 	switch (x) {
@@ -16,8 +38,166 @@ bool ipmi_bootdev_is_valid(int x)
 	return false;
 }
 
+static int ipmi_send(struct ipmi *ipmi, uint8_t netfn, uint8_t cmd,
+		uint8_t *buf, uint16_t len)
+{
+	struct ipmi_system_interface_addr addr;
+	struct ipmi_req req;
+	int rc;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+
+	memset(&req, 0, sizeof(req));
+	req.addr = (unsigned char *)&addr;
+	req.addr_len = sizeof(addr);
+
+	req.msgid = ipmi->seq++;
+
+	req.msg.data = buf;
+	req.msg.data_len = len;
+	req.msg.netfn = netfn;
+	req.msg.cmd = cmd;
+
+	rc = ioctl(ipmi->fd, IPMICTL_SEND_COMMAND, &req);
+	if (rc < 0) {
+		pb_log("IPMI: send (netfn %d, cmd %d, %d bytes) failed: %m\n",
+				netfn, cmd, len);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int ipmi_recv(struct ipmi *ipmi, uint8_t *netfn, uint8_t *cmd,
+		long *seq, uint8_t *buf, uint16_t *len)
+{
+	struct ipmi_recv recv;
+	struct ipmi_addr addr;
+	int rc;
+
+	recv.addr = (unsigned char *)&addr;
+	recv.addr_len = sizeof(addr);
+	recv.msg.data = buf;
+	recv.msg.data_len = *len;
+
+	rc = ioctl(ipmi->fd, IPMICTL_RECEIVE_MSG_TRUNC, &recv);
+	if (rc < 0 && errno != EMSGSIZE) {
+		pb_log("IPMI: recv (%d bytes) failed: %m\n", *len);
+		return -1;
+	} else if (rc < 0 && errno == EMSGSIZE) {
+		pb_debug("IPMI: truncated message (netfn %d, cmd %d, "
+				"size %d), continuing anyway\n",
+				recv.msg.netfn, recv.msg.cmd, *len);
+	}
+
+	*netfn = recv.msg.netfn;
+	*cmd = recv.msg.cmd;
+	*seq = recv.msgid;
+	*len = recv.msg.data_len;
+
+	return 0;
+}
+
+int ipmi_transaction(struct ipmi *ipmi, uint8_t netfn, uint8_t cmd,
+		uint8_t *req_buf, uint16_t req_len,
+		uint8_t *resp_buf, uint16_t *resp_len,
+		int timeout_ms)
+{
+	struct timeval start, now, delta;
+	struct pollfd pollfds[1];
+	int expired_ms, rc;
+
+	rc = ipmi_send(ipmi, netfn, cmd, req_buf, req_len);
+	if (rc)
+		return rc;
+
+	pollfds[0].fd = ipmi->fd;
+	pollfds[0].events = POLLIN;
+
+	gettimeofday(&start, NULL);
+	expired_ms = 0;
+
+	for (;;) {
+		uint8_t resp_netfn, resp_cmd;
+		long seq;
+
+		rc = poll(pollfds, 1, timeout_ms - expired_ms);
+
+		if (rc < 0) {
+			pb_log("IPMI: poll() error %m");
+			break;
+		}
+		if (rc == 0) {
+			pb_log("IPMI: timeout waiting for response "
+					"(netfn %d, cmd %d)\n", netfn, cmd);
+			break;
+		}
+
+		if (!(pollfds[0].revents & POLLIN)) {
+			pb_log("IPMI: unexpected fd status from poll?\n");
+			break;
+		}
+
+		rc = ipmi_recv(ipmi, &resp_netfn, &resp_cmd, &seq,
+				resp_buf, resp_len);
+		if (rc)
+			break;
+
+		if (seq != ipmi->seq - 1) {
+			pb_log("IPMI: out-of-sequence reply: "
+					"exp %ld, got %ld\n",
+					ipmi->seq, seq);
+
+			if (timeout_ms) {
+				gettimeofday(&now, NULL);
+				timersub(&now, &start, &delta);
+				expired_ms = (delta.tv_sec * 1000) +
+						(delta.tv_usec / 1000);
+
+				if (expired_ms >= timeout_ms)
+					break;
+			}
+		} else {
+			pb_debug("IPMI: netfn(%x->%x), cmd(%x->%x)\n",
+					netfn, resp_netfn, cmd, resp_cmd);
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+static int ipmi_destroy(void *p)
+{
+	struct ipmi *ipmi = p;
+	close(ipmi->fd);
+	return 1;
+}
+
+struct ipmi *ipmi_open(void *ctx)
+{
+	struct ipmi *ipmi;
+	int fd;
+
+	fd = open(ipmi_devnode, O_RDWR);
+	if (fd < 0) {
+		pb_log("IPMI: can't open IPMI device %s: %m\n", ipmi_devnode);
+		return NULL;
+	}
+
+	ipmi = talloc(ctx, struct ipmi);
+	ipmi->fd = fd;
+	ipmi->seq = 0;
+
+	talloc_set_destructor(ipmi, ipmi_destroy);
+
+	return ipmi;
+}
+
 bool ipmi_present(void)
 {
-	return false;
+	return !access(ipmi_devnode, R_OK | W_OK);
 }