Merge tag 'for-linus-6.18-1' of https://github.com/cminyard/linux-ipmi

Pull IPMI updates from Corey Minyard:
 "Bug fixes and enhancements for IPMI

  This fixes a number of small bugs, but has some more major changes:

   - Loongson-2K BMC support is added. This is an MFD device and is
     dependent on the changes coming from that tree.

     The way the driver handles BMCs that have become non-functional has
     been completely redone. A number of changes in the past have
     attempted to handle various issues around this, but nothing has
     been very good. After working with some people on this, the code
     has been reworked to disable the driver and fail all pending
     operations if the BMC becomes non functional. It will retry the BMC
     once a second to see if it's back up"

* tag 'for-linus-6.18-1' of https://github.com/cminyard/linux-ipmi:
  ipmi: Add Loongson-2K BMC support
  ipmi:si: Gracefully handle if the BMC is non-functional
  ipmi: Rename "user_data" to "recv_msg" in an SMI message
  ipmi: Allow an SMI sender to return an error
  ipmi:si: Move flags get start to its own function
  ipmi:si: Merge some if statements
  ipmi: Set a timer for maintenance mode
  ipmi: Add a maintenance mode sysfs file
  ipmi: Disable sysfs access and requests in maintenance mode
  ipmi: Differentiate between reset and firmware update in maintenance
  dt-bindings: ipmi: aspeed,ast2400-kcs-bmc: Add missing "clocks" property
  ipmi: Rework user message limit handling
  Revert "ipmi: fix msg stack when IPMI is disconnected"
  ipmi:msghandler:Change seq_lock to a mutex

12 files changed, 600 insertions, 338 deletions

diff --git a/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml b/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml
index 129e32c4c774..610c79863208 100644
--- a/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml
+++ b/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml
@@ -40,6 +40,9 @@ properties:
       - description: ODR register
       - description: STR register
 
+  clocks:
+    maxItems: 1
+
   aspeed,lpc-io-reg:
     $ref: /schemas/types.yaml#/definitions/uint32-array
     minItems: 1
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index f4adc6feb3b2..92bed266d07c 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -84,6 +84,13 @@ config IPMI_IPMB
 	  bus, and it also supports direct messaging on the bus using
 	  IPMB direct messages.  This module requires I2C support.
 
+config IPMI_LS2K
+	bool 'Loongson-2K IPMI interface'
+	depends on LOONGARCH
+	select MFD_LS2K_BMC_CORE
+	help
+	  Provides a driver for Loongson-2K IPMI interfaces.
+
 config IPMI_POWERNV
 	depends on PPC_POWERNV
 	tristate 'POWERNV (OPAL firmware) IPMI interface'
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index e0944547c9d0..4ea450a82242 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -8,6 +8,7 @@ ipmi_si-y := ipmi_si_intf.o ipmi_kcs_sm.o ipmi_smic_sm.o ipmi_bt_sm.o \
 	ipmi_si_mem_io.o
 ipmi_si-$(CONFIG_HAS_IOPORT) += ipmi_si_port_io.o
 ipmi_si-$(CONFIG_PCI) += ipmi_si_pci.o
+ipmi_si-$(CONFIG_IPMI_LS2K) += ipmi_si_ls2k.o
 ipmi_si-$(CONFIG_PARISC) += ipmi_si_parisc.o
 
 obj-$(CONFIG_IPMI_HANDLER) += ipmi_msghandler.o
diff --git a/drivers/char/ipmi/ipmi_ipmb.c b/drivers/char/ipmi/ipmi_ipmb.c
index 6a4f279c7c1f..3a51e58b2487 100644
--- a/drivers/char/ipmi/ipmi_ipmb.c
+++ b/drivers/char/ipmi/ipmi_ipmb.c
@@ -404,8 +404,7 @@ static void ipmi_ipmb_shutdown(void *send_info)
 	ipmi_ipmb_stop_thread(iidev);
 }
 
-static void ipmi_ipmb_sender(void *send_info,
-			     struct ipmi_smi_msg *msg)
+static int ipmi_ipmb_sender(void *send_info, struct ipmi_smi_msg *msg)
 {
 	struct ipmi_ipmb_dev *iidev = send_info;
 	unsigned long flags;
@@ -417,6 +416,7 @@ static void ipmi_ipmb_sender(void *send_info,
 	spin_unlock_irqrestore(&iidev->lock, flags);
 
 	up(&iidev->wake_thread);
+	return IPMI_CC_NO_ERROR;
 }
 
 static void ipmi_ipmb_request_events(void *send_info)
diff --git a/drivers/char/ipmi/ipmi_kcs_sm.c b/drivers/char/ipmi/ipmi_kcs_sm.c
index ecfcb50302f6..efda90dcf5b3 100644
--- a/drivers/char/ipmi/ipmi_kcs_sm.c
+++ b/drivers/char/ipmi/ipmi_kcs_sm.c
@@ -122,10 +122,10 @@ struct si_sm_data {
 	unsigned long  error0_timeout;
 };
 
-static unsigned int init_kcs_data_with_state(struct si_sm_data *kcs,
-				  struct si_sm_io *io, enum kcs_states state)
+static unsigned int init_kcs_data(struct si_sm_data *kcs,
+				  struct si_sm_io *io)
 {
-	kcs->state = state;
+	kcs->state = KCS_IDLE;
 	kcs->io = io;
 	kcs->write_pos = 0;
 	kcs->write_count = 0;
@@ -140,12 +140,6 @@ static unsigned int init_kcs_data_with_state(struct si_sm_data *kcs,
 	return 2;
 }
 
-static unsigned int init_kcs_data(struct si_sm_data *kcs,
-				  struct si_sm_io *io)
-{
-	return init_kcs_data_with_state(kcs, io, KCS_IDLE);
-}
-
 static inline unsigned char read_status(struct si_sm_data *kcs)
 {
 	return kcs->io->inputb(kcs->io, 1);
@@ -276,7 +270,7 @@ static int start_kcs_transaction(struct si_sm_data *kcs, unsigned char *data,
 	if (size > MAX_KCS_WRITE_SIZE)
 		return IPMI_REQ_LEN_EXCEEDED_ERR;
 
-	if (kcs->state != KCS_IDLE) {
+	if ((kcs->state != KCS_IDLE) && (kcs->state != KCS_HOSED)) {
 		dev_warn(kcs->io->dev, "KCS in invalid state %d\n", kcs->state);
 		return IPMI_NOT_IN_MY_STATE_ERR;
 	}
@@ -501,7 +495,7 @@ static enum si_sm_result kcs_event(struct si_sm_data *kcs, long time)
 	}
 
 	if (kcs->state == KCS_HOSED) {
-		init_kcs_data_with_state(kcs, kcs->io, KCS_ERROR0);
+		init_kcs_data(kcs, kcs->io);
 		return SI_SM_HOSED;
 	}
 
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 8e9050f99e9e..a0b67a35a5f0 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -38,7 +38,9 @@
 
 #define IPMI_DRIVER_VERSION "39.2"
 
-static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
+static struct ipmi_recv_msg *ipmi_alloc_recv_msg(struct ipmi_user *user);
+static void ipmi_set_recv_msg_user(struct ipmi_recv_msg *msg,
+				   struct ipmi_user *user);
 static int ipmi_init_msghandler(void);
 static void smi_work(struct work_struct *t);
 static void handle_new_recv_msgs(struct ipmi_smi *intf);
@@ -50,6 +52,8 @@ static void intf_free(struct kref *ref);
 static bool initialized;
 static bool drvregistered;
 
+static struct timer_list ipmi_timer;
+
 /* Numbers in this enumerator should be mapped to ipmi_panic_event_str */
 enum ipmi_panic_event_op {
 	IPMI_SEND_PANIC_EVENT_NONE,
@@ -432,6 +436,7 @@ struct ipmi_smi {
 	atomic_t nr_users;
 	struct device_attribute nr_users_devattr;
 	struct device_attribute nr_msgs_devattr;
+	struct device_attribute maintenance_mode_devattr;
 
 
 	/* Used for wake ups at startup. */
@@ -464,7 +469,7 @@ struct ipmi_smi {
 	 * interface to match them up with their responses.  A routine
 	 * is called periodically to time the items in this list.
 	 */
-	spinlock_t       seq_lock;
+	struct mutex seq_lock;
 	struct seq_table seq_table[IPMI_IPMB_NUM_SEQ];
 	int curr_seq;
 
@@ -539,7 +544,11 @@ struct ipmi_smi {
 
 	/* For handling of maintenance mode. */
 	int maintenance_mode;
-	bool maintenance_mode_enable;
+
+#define IPMI_MAINTENANCE_MODE_STATE_OFF		0
+#define IPMI_MAINTENANCE_MODE_STATE_FIRMWARE	1
+#define IPMI_MAINTENANCE_MODE_STATE_RESET	2
+	int maintenance_mode_state;
 	int auto_maintenance_timeout;
 	spinlock_t maintenance_mode_lock; /* Used in a timer... */
 
@@ -955,7 +964,6 @@ static int deliver_response(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
 		 * risk.  At this moment, simply skip it in that case.
 		 */
 		ipmi_free_recv_msg(msg);
-		atomic_dec(&msg->user->nr_msgs);
 	} else {
 		/*
 		 * Deliver it in smi_work.  The message will hold a
@@ -1116,12 +1124,11 @@ static int intf_find_seq(struct ipmi_smi      *intf,
 			 struct ipmi_recv_msg **recv_msg)
 {
 	int           rv = -ENODEV;
-	unsigned long flags;
 
 	if (seq >= IPMI_IPMB_NUM_SEQ)
 		return -EINVAL;
 
-	spin_lock_irqsave(&intf->seq_lock, flags);
+	mutex_lock(&intf->seq_lock);
 	if (intf->seq_table[seq].inuse) {
 		struct ipmi_recv_msg *msg = intf->seq_table[seq].recv_msg;
 
@@ -1134,7 +1141,7 @@ static int intf_find_seq(struct ipmi_smi      *intf,
 			rv = 0;
 		}
 	}
-	spin_unlock_irqrestore(&intf->seq_lock, flags);
+	mutex_unlock(&intf->seq_lock);
 
 	return rv;
 }
@@ -1145,14 +1152,13 @@ static int intf_start_seq_timer(struct ipmi_smi *intf,
 				long       msgid)
 {
 	int           rv = -ENODEV;
-	unsigned long flags;
 	unsigned char seq;
 	unsigned long seqid;
 
 
 	GET_SEQ_FROM_MSGID(msgid, seq, seqid);
 
-	spin_lock_irqsave(&intf->seq_lock, flags);
+	mutex_lock(&intf->seq_lock);
 	/*
 	 * We do this verification because the user can be deleted
 	 * while a message is outstanding.
@@ -1163,7 +1169,7 @@ static int intf_start_seq_timer(struct ipmi_smi *intf,
 		ent->timeout = ent->orig_timeout;
 		rv = 0;
 	}
-	spin_unlock_irqrestore(&intf->seq_lock, flags);
+	mutex_unlock(&intf->seq_lock);
 
 	return rv;
 }
@@ -1174,7 +1180,6 @@ static int intf_err_seq(struct ipmi_smi *intf,
 			unsigned int err)
 {
 	int                  rv = -ENODEV;
-	unsigned long        flags;
 	unsigned char        seq;
 	unsigned long        seqid;
 	struct ipmi_recv_msg *msg = NULL;
@@ -1182,7 +1187,7 @@ static int intf_err_seq(struct ipmi_smi *intf,
 
 	GET_SEQ_FROM_MSGID(msgid, seq, seqid);
 
-	spin_lock_irqsave(&intf->seq_lock, flags);
+	mutex_lock(&intf->seq_lock);
 	/*
 	 * We do this verification because the user can be deleted
 	 * while a message is outstanding.
@@ -1196,7 +1201,7 @@ static int intf_err_seq(struct ipmi_smi *intf,
 		msg = ent->recv_msg;
 		rv = 0;
 	}
-	spin_unlock_irqrestore(&intf->seq_lock, flags);
+	mutex_unlock(&intf->seq_lock);
 
 	if (msg)
 		deliver_err_response(intf, msg, err);
@@ -1209,7 +1214,6 @@ int ipmi_create_user(unsigned int          if_num,
 		     void                  *handler_data,
 		     struct ipmi_user      **user)
 {
-	unsigned long flags;
 	struct ipmi_user *new_user = NULL;
 	int           rv = 0;
 	struct ipmi_smi *intf;
@@ -1277,9 +1281,9 @@ int ipmi_create_user(unsigned int          if_num,
 	new_user->gets_events = false;
 
 	mutex_lock(&intf->users_mutex);
-	spin_lock_irqsave(&intf->seq_lock, flags);
+	mutex_lock(&intf->seq_lock);
 	list_add(&new_user->link, &intf->users);
-	spin_unlock_irqrestore(&intf->seq_lock, flags);
+	mutex_unlock(&intf->seq_lock);
 	mutex_unlock(&intf->users_mutex);
 
 	if (handler->ipmi_watchdog_pretimeout)
@@ -1325,7 +1329,6 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 {
 	struct ipmi_smi  *intf = user->intf;
 	int              i;
-	unsigned long    flags;
 	struct cmd_rcvr  *rcvr;
 	struct cmd_rcvr  *rcvrs = NULL;
 	struct ipmi_recv_msg *msg, *msg2;
@@ -1346,7 +1349,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 	list_del(&user->link);
 	atomic_dec(&intf->nr_users);
 
-	spin_lock_irqsave(&intf->seq_lock, flags);
+	mutex_lock(&intf->seq_lock);
 	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
 		if (intf->seq_table[i].inuse
 		    && (intf->seq_table[i].recv_msg->user == user)) {
@@ -1355,7 +1358,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 			ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
 		}
 	}
-	spin_unlock_irqrestore(&intf->seq_lock, flags);
+	mutex_unlock(&intf->seq_lock);
 
 	/*
 	 * Remove the user from the command receiver's table.  First
@@ -1534,8 +1537,15 @@ EXPORT_SYMBOL(ipmi_get_maintenance_mode);
 static void maintenance_mode_update(struct ipmi_smi *intf)
 {
 	if (intf->handlers->set_maintenance_mode)
+		/*
+		 * Lower level drivers only care about firmware mode
+		 * as it affects their timing.  They don't care about
+		 * reset, which disables all commands for a while.
+		 */
 		intf->handlers->set_maintenance_mode(
-			intf->send_info, intf->maintenance_mode_enable);
+			intf->send_info,
+			(intf->maintenance_mode_state ==
+			 IPMI_MAINTENANCE_MODE_STATE_FIRMWARE));
 }
 
 int ipmi_set_maintenance_mode(struct ipmi_user *user, int mode)
@@ -1552,16 +1562,17 @@ int ipmi_set_maintenance_mode(struct ipmi_user *user, int mode)
 	if (intf->maintenance_mode != mode) {
 		switch (mode) {
 		case IPMI_MAINTENANCE_MODE_AUTO:
-			intf->maintenance_mode_enable
-				= (intf->auto_maintenance_timeout > 0);
+			/* Just leave it alone. */
 			break;
 
 		case IPMI_MAINTENANCE_MODE_OFF:
-			intf->maintenance_mode_enable = false;
+			intf->maintenance_mode_state =
+				IPMI_MAINTENANCE_MODE_STATE_OFF;
 			break;
 
 		case IPMI_MAINTENANCE_MODE_ON:
-			intf->maintenance_mode_enable = true;
+			intf->maintenance_mode_state =
+				IPMI_MAINTENANCE_MODE_STATE_FIRMWARE;
 			break;
 
 		default:
@@ -1616,8 +1627,7 @@ int ipmi_set_gets_events(struct ipmi_user *user, bool val)
 		}
 
 		list_for_each_entry_safe(msg, msg2, &msgs, link) {
-			msg->user = user;
-			kref_get(&user->refcount);
+			ipmi_set_recv_msg_user(msg, user);
 			deliver_local_response(intf, msg);
 		}
 	}
@@ -1922,14 +1932,20 @@ static int i_ipmi_req_sysintf(struct ipmi_smi        *intf,
 
 	if (is_maintenance_mode_cmd(msg)) {
 		unsigned long flags;
+		int newst;
+
+		if (msg->netfn == IPMI_NETFN_FIRMWARE_REQUEST)
+			newst = IPMI_MAINTENANCE_MODE_STATE_FIRMWARE;
+		else
+			newst = IPMI_MAINTENANCE_MODE_STATE_RESET;
 
 		spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
-		intf->auto_maintenance_timeout
-			= maintenance_mode_timeout_ms;
+		intf->auto_maintenance_timeout = maintenance_mode_timeout_ms;
 		if (!intf->maintenance_mode
-		    && !intf->maintenance_mode_enable) {
-			intf->maintenance_mode_enable = true;
+				&& intf->maintenance_mode_state < newst) {
+			intf->maintenance_mode_state = newst;
 			maintenance_mode_update(intf);
+			mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
 		}
 		spin_unlock_irqrestore(&intf->maintenance_mode_lock,
 				       flags);
@@ -1943,7 +1959,7 @@ static int i_ipmi_req_sysintf(struct ipmi_smi        *intf,
 	smi_msg->data[0] = (msg->netfn << 2) | (smi_addr->lun & 0x3);
 	smi_msg->data[1] = msg->cmd;
 	smi_msg->msgid = msgid;
-	smi_msg->user_data = recv_msg;
+	smi_msg->recv_msg = recv_msg;
 	if (msg->data_len > 0)
 		memcpy(&smi_msg->data[2], msg->data, msg->data_len);
 	smi_msg->data_size = msg->data_len + 2;
@@ -2024,12 +2040,9 @@ static int i_ipmi_req_ipmb(struct ipmi_smi        *intf,
 		 * Save the receive message so we can use it
 		 * to deliver the response.
 		 */
-		smi_msg->user_data = recv_msg;
+		smi_msg->recv_msg = recv_msg;
 	} else {
-		/* It's a command, so get a sequence for it. */
-		unsigned long flags;
-
-		spin_lock_irqsave(&intf->seq_lock, flags);
+		mutex_lock(&intf->seq_lock);
 
 		if (is_maintenance_mode_cmd(msg))
 			intf->ipmb_maintenance_mode_timeout =
@@ -2087,7 +2100,7 @@ static int i_ipmi_req_ipmb(struct ipmi_smi        *intf,
 		 * to be correct.
 		 */
 out_err:
-		spin_unlock_irqrestore(&intf->seq_lock, flags);
+		mutex_unlock(&intf->seq_lock);
 	}
 
 	return rv;
@@ -2140,7 +2153,7 @@ static int i_ipmi_req_ipmb_direct(struct ipmi_smi        *intf,
 	memcpy(smi_msg->data + 4, msg->data, msg->data_len);
 	smi_msg->data_size = msg->data_len + 4;
 
-	smi_msg->user_data = recv_msg;
+	smi_msg->recv_msg = recv_msg;
 
 	return 0;
 }
@@ -2203,12 +2216,9 @@ static int i_ipmi_req_lan(struct ipmi_smi        *intf,
 		 * Save the receive message so we can use it
 		 * to deliver the response.
 		 */
-		smi_msg->user_data = recv_msg;
+		smi_msg->recv_msg = recv_msg;
 	} else {
-		/* It's a command, so get a sequence for it. */
-		unsigned long flags;
-
-		spin_lock_irqsave(&intf->seq_lock, flags);
+		mutex_lock(&intf->seq_lock);
 
 		/*
 		 * Create a sequence number with a 1 second
@@ -2257,7 +2267,7 @@ static int i_ipmi_req_lan(struct ipmi_smi        *intf,
 		 * to be correct.
 		 */
 out_err:
-		spin_unlock_irqrestore(&intf->seq_lock, flags);
+		mutex_unlock(&intf->seq_lock);
 	}
 
 	return rv;
@@ -2288,22 +2298,15 @@ static int i_ipmi_request(struct ipmi_user     *user,
 	int run_to_completion = READ_ONCE(intf->run_to_completion);
 	int rv = 0;
 
-	if (user) {
-		if (atomic_add_return(1, &user->nr_msgs) > max_msgs_per_user) {
-			/* Decrement will happen at the end of the routine. */
-			rv = -EBUSY;
-			goto out;
-		}
-	}
-
-	if (supplied_recv)
+	if (supplied_recv) {
 		recv_msg = supplied_recv;
-	else {
-		recv_msg = ipmi_alloc_recv_msg();
-		if (recv_msg == NULL) {
-			rv = -ENOMEM;
-			goto out;
-		}
+		recv_msg->user = user;
+		if (user)
+			atomic_inc(&user->nr_msgs);
+	} else {
+		recv_msg = ipmi_alloc_recv_msg(user);
+		if (IS_ERR(recv_msg))
+			return PTR_ERR(recv_msg);
 	}
 	recv_msg->user_msg_data = user_msg_data;
 
@@ -2314,22 +2317,22 @@ static int i_ipmi_request(struct ipmi_user     *user,
 		if (smi_msg == NULL) {
 			if (!supplied_recv)
 				ipmi_free_recv_msg(recv_msg);
-			rv = -ENOMEM;
-			goto out;
+			return -ENOMEM;
 		}
 	}
 
 	if (!run_to_completion)
 		mutex_lock(&intf->users_mutex);
+	if (intf->maintenance_mode_state == IPMI_MAINTENANCE_MODE_STATE_RESET) {
+		/* No messages while the BMC is in reset. */
+		rv = -EBUSY;
+		goto out_err;
+	}
 	if (intf->in_shutdown) {
 		rv = -ENODEV;
 		goto out_err;
 	}
 
-	recv_msg->user = user;
-	if (user)
-		/* The put happens when the message is freed. */
-		kref_get(&user->refcount);
 	recv_msg->msgid = msgid;
 	/*
 	 * Store the message to send in the receive message so timeout
@@ -2358,8 +2361,10 @@ static int i_ipmi_request(struct ipmi_user     *user,
 
 	if (rv) {
 out_err:
-		ipmi_free_smi_msg(smi_msg);
-		ipmi_free_recv_msg(recv_msg);
+		if (!supplied_smi)
+			ipmi_free_smi_msg(smi_msg);
+		if (!supplied_recv)
+			ipmi_free_recv_msg(recv_msg);
 	} else {
 		dev_dbg(intf->si_dev, "Send: %*ph\n",
 			smi_msg->data_size, smi_msg->data);
@@ -2369,9 +2374,6 @@ out_err:
 	if (!run_to_completion)
 		mutex_unlock(&intf->users_mutex);
 
-out:
-	if (rv && user)
-		atomic_dec(&user->nr_msgs);
 	return rv;
 }
 
@@ -2622,6 +2624,12 @@ retry_bmc_lock:
 	    (bmc->dyn_id_set && time_is_after_jiffies(bmc->dyn_id_expiry)))
 		goto out_noprocessing;
 
+	/* Don't allow sysfs access when in maintenance mode. */
+	if (intf->maintenance_mode_state) {
+		rv = -EBUSY;
+		goto out_noprocessing;
+	}
+
 	prev_guid_set = bmc->dyn_guid_set;
 	__get_guid(intf);
 
@@ -3517,6 +3525,19 @@ static ssize_t nr_msgs_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(nr_msgs);
 
+static ssize_t maintenance_mode_show(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct ipmi_smi *intf = container_of(attr,
+					     struct ipmi_smi,
+					     maintenance_mode_devattr);
+
+	return sysfs_emit(buf, "%u %d\n", intf->maintenance_mode_state,
+			  intf->auto_maintenance_timeout);
+}
+static DEVICE_ATTR_RO(maintenance_mode);
+
 static void redo_bmc_reg(struct work_struct *work)
 {
 	struct ipmi_smi *intf = container_of(work, struct ipmi_smi,
@@ -3575,7 +3596,7 @@ int ipmi_add_smi(struct module         *owner,
 	atomic_set(&intf->nr_users, 0);
 	intf->handlers = handlers;
 	intf->send_info = send_info;
-	spin_lock_init(&intf->seq_lock);
+	mutex_init(&intf->seq_lock);
 	for (j = 0; j < IPMI_IPMB_NUM_SEQ; j++) {
 		intf->seq_table[j].inuse = 0;
 		intf->seq_table[j].seqid = 0;
@@ -3653,6 +3674,14 @@ int ipmi_add_smi(struct module         *owner,
 		goto out_err_bmc_reg;
 	}
 
+	intf->maintenance_mode_devattr = dev_attr_maintenance_mode;
+	sysfs_attr_init(&intf->maintenance_mode_devattr.attr);
+	rv = device_create_file(intf->si_dev, &intf->maintenance_mode_devattr);
+	if (rv) {
+		device_remove_file(intf->si_dev, &intf->nr_users_devattr);
+		goto out_err_bmc_reg;
+	}
+
 	intf->intf_num = i;
 	mutex_unlock(&ipmi_interfaces_mutex);
 
@@ -3760,6 +3789,7 @@ void ipmi_unregister_smi(struct ipmi_smi *intf)
 	if (intf->handlers->shutdown)
 		intf->handlers->shutdown(intf->send_info);
 
+	device_remove_file(intf->si_dev, &intf->maintenance_mode_devattr);
 	device_remove_file(intf->si_dev, &intf->nr_msgs_devattr);
 	device_remove_file(intf->si_dev, &intf->nr_users_devattr);
 
@@ -3862,7 +3892,7 @@ static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
 	unsigned char            chan;
 	struct ipmi_user         *user = NULL;
 	struct ipmi_ipmb_addr    *ipmb_addr;
-	struct ipmi_recv_msg     *recv_msg;
+	struct ipmi_recv_msg     *recv_msg = NULL;
 
 	if (msg->rsp_size < 10) {
 		/* Message not big enough, just ignore it. */
@@ -3883,9 +3913,8 @@ static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
 	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
 	if (rcvr) {
 		user = rcvr->user;
-		kref_get(&user->refcount);
-	} else
-		user = NULL;
+		recv_msg = ipmi_alloc_recv_msg(user);
+	}
 	rcu_read_unlock();
 
 	if (user == NULL) {
@@ -3915,47 +3944,41 @@ static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
 		 * causes it to not be freed or queued.
 		 */
 		rv = -1;
-	} else {
-		recv_msg = ipmi_alloc_recv_msg();
-		if (!recv_msg) {
-			/*
-			 * We couldn't allocate memory for the
-			 * message, so requeue it for handling
-			 * later.
-			 */
-			rv = 1;
-			kref_put(&user->refcount, free_ipmi_user);
-		} else {
-			/* Extract the source address from the data. */
-			ipmb_addr = (struct ipmi_ipmb_addr *) &recv_msg->addr;
-			ipmb_addr->addr_type = IPMI_IPMB_ADDR_TYPE;
-			ipmb_addr->slave_addr = msg->rsp[6];
-			ipmb_addr->lun = msg->rsp[7] & 3;
-			ipmb_addr->channel = msg->rsp[3] & 0xf;
+	} else if (!IS_ERR(recv_msg)) {
+		/* Extract the source address from the data. */
+		ipmb_addr = (struct ipmi_ipmb_addr *) &recv_msg->addr;
+		ipmb_addr->addr_type = IPMI_IPMB_ADDR_TYPE;
+		ipmb_addr->slave_addr = msg->rsp[6];
+		ipmb_addr->lun = msg->rsp[7] & 3;
+		ipmb_addr->channel = msg->rsp[3] & 0xf;
 
-			/*
-			 * Extract the rest of the message information
-			 * from the IPMB header.
-			 */
-			recv_msg->user = user;
-			recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
-			recv_msg->msgid = msg->rsp[7] >> 2;
-			recv_msg->msg.netfn = msg->rsp[4] >> 2;
-			recv_msg->msg.cmd = msg->rsp[8];
-			recv_msg->msg.data = recv_msg->msg_data;
+		/*
+		 * Extract the rest of the message information
+		 * from the IPMB header.
+		 */
+		recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
+		recv_msg->msgid = msg->rsp[7] >> 2;
+		recv_msg->msg.netfn = msg->rsp[4] >> 2;
+		recv_msg->msg.cmd = msg->rsp[8];
+		recv_msg->msg.data = recv_msg->msg_data;
 
-			/*
-			 * We chop off 10, not 9 bytes because the checksum
-			 * at the end also needs to be removed.
-			 */
-			recv_msg->msg.data_len = msg->rsp_size - 10;
-			memcpy(recv_msg->msg_data, &msg->rsp[9],
-			       msg->rsp_size - 10);
-			if (deliver_response(intf, recv_msg))
-				ipmi_inc_stat(intf, unhandled_commands);
-			else
-				ipmi_inc_stat(intf, handled_commands);
-		}
+		/*
+		 * We chop off 10, not 9 bytes because the checksum
+		 * at the end also needs to be removed.
+		 */
+		recv_msg->msg.data_len = msg->rsp_size - 10;
+		memcpy(recv_msg->msg_data, &msg->rsp[9],
+		       msg->rsp_size - 10);
+		if (deliver_response(intf, recv_msg))
+			ipmi_inc_stat(intf, unhandled_commands);
+		else
+			ipmi_inc_stat(intf, handled_commands);
+	} else {
+		/*
+		 * We couldn't allocate memory for the message, so
+		 * requeue it for handling later.
+		 */
+		rv = 1;
 	}
 
 	return rv;
@@ -3968,7 +3991,7 @@ static int handle_ipmb_direct_rcv_cmd(struct ipmi_smi *intf,
 	int                      rv = 0;
 	struct ipmi_user         *user = NULL;
 	struct ipmi_ipmb_direct_addr *daddr;
-	struct ipmi_recv_msg     *recv_msg;
+	struct ipmi_recv_msg     *recv_msg = NULL;
 	unsigned char netfn = msg->rsp[0] >> 2;
 	unsigned char cmd = msg->rsp[3];
 
@@ -3977,9 +4000,8 @@ static int handle_ipmb_direct_rcv_cmd(struct ipmi_smi *intf,
 	rcvr = find_cmd_rcvr(intf, netfn, cmd, 0);
 	if (rcvr) {
 		user = rcvr->user;
-		kref_get(&user->refcount);
-	} else
-		user = NULL;
+		recv_msg = ipmi_alloc_recv_msg(user);
+	}
 	rcu_read_unlock();
 
 	if (user == NULL) {
@@ -4001,44 +4023,38 @@ static int handle_ipmb_direct_rcv_cmd(struct ipmi_smi *intf,
 		 * causes it to not be freed or queued.
 		 */
 		rv = -1;
-	} else {
-		recv_msg = ipmi_alloc_recv_msg();
-		if (!recv_msg) {
-			/*
-			 * We couldn't allocate memory for the
-			 * message, so requeue it for handling
-			 * later.
-			 */
-			rv = 1;
-			kref_put(&user->refcount, free_ipmi_user);
-		} else {
-			/* Extract the source address from the data. */
-			daddr = (struct ipmi_ipmb_direct_addr *)&recv_msg->addr;
-			daddr->addr_type = IPMI_IPMB_DIRECT_ADDR_TYPE;
-			daddr->channel = 0;
-			daddr->slave_addr = msg->rsp[1];
-			daddr->rs_lun = msg->rsp[0] & 3;
-			daddr->rq_lun = msg->rsp[2] & 3;
+	} else if (!IS_ERR(recv_msg)) {
+		/* Extract the source address from the data. */
+		daddr = (struct ipmi_ipmb_direct_addr *)&recv_msg->addr;
+		daddr->addr_type = IPMI_IPMB_DIRECT_ADDR_TYPE;
+		daddr->channel = 0;
+		daddr->slave_addr = msg->rsp[1];
+		daddr->rs_lun = msg->rsp[0] & 3;
+		daddr->rq_lun = msg->rsp[2] & 3;
 
-			/*
-			 * Extract the rest of the message information
-			 * from the IPMB header.
-			 */
-			recv_msg->user = user;
-			recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
-			recv_msg->msgid = (msg->rsp[2] >> 2);
-			recv_msg->msg.netfn = msg->rsp[0] >> 2;
-			recv_msg->msg.cmd = msg->rsp[3];
-			recv_msg->msg.data = recv_msg->msg_data;
-
-			recv_msg->msg.data_len = msg->rsp_size - 4;
-			memcpy(recv_msg->msg_data, msg->rsp + 4,
-			       msg->rsp_size - 4);
-			if (deliver_response(intf, recv_msg))
-				ipmi_inc_stat(intf, unhandled_commands);
-			else
-				ipmi_inc_stat(intf, handled_commands);
-		}
+		/*
+		 * Extract the rest of the message information
+		 * from the IPMB header.
+		 */
+		recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
+		recv_msg->msgid = (msg->rsp[2] >> 2);
+		recv_msg->msg.netfn = msg->rsp[0] >> 2;
+		recv_msg->msg.cmd = msg->rsp[3];
+		recv_msg->msg.data = recv_msg->msg_data;
+
+		recv_msg->msg.data_len = msg->rsp_size - 4;
+		memcpy(recv_msg->msg_data, msg->rsp + 4,
+		       msg->rsp_size - 4);
+		if (deliver_response(intf, recv_msg))
+			ipmi_inc_stat(intf, unhandled_commands);
+		else
+			ipmi_inc_stat(intf, handled_commands);
+	} else {
+		/*
+		 * We couldn't allocate memory for the message, so
+		 * requeue it for handling later.
+		 */
+		rv = 1;
 	}
 
 	return rv;
@@ -4050,7 +4066,7 @@ static int handle_ipmb_direct_rcv_rsp(struct ipmi_smi *intf,
 	struct ipmi_recv_msg *recv_msg;
 	struct ipmi_ipmb_direct_addr *daddr;
 
-	recv_msg = msg->user_data;
+	recv_msg = msg->recv_msg;
 	if (recv_msg == NULL) {
 		dev_warn(intf->si_dev,
 			 "IPMI direct message received with no owner. This could be because of a malformed message, or because of a hardware error.  Contact your hardware vendor for assistance.\n");
@@ -4152,7 +4168,7 @@ static int handle_lan_get_msg_cmd(struct ipmi_smi *intf,
 	unsigned char            chan;
 	struct ipmi_user         *user = NULL;
 	struct ipmi_lan_addr     *lan_addr;
-	struct ipmi_recv_msg     *recv_msg;
+	struct ipmi_recv_msg     *recv_msg = NULL;
 
 	if (msg->rsp_size < 12) {
 		/* Message not big enough, just ignore it. */
@@ -4173,9 +4189,8 @@ static int handle_lan_get_msg_cmd(struct ipmi_smi *intf,
 	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
 	if (rcvr) {
 		user = rcvr->user;
-		kref_get(&user->refcount);
-	} else
-		user = NULL;
+		recv_msg = ipmi_alloc_recv_msg(user);
+	}
 	rcu_read_unlock();
 
 	if (user == NULL) {
@@ -4206,49 +4221,44 @@ static int handle_lan_get_msg_cmd(struct ipmi_smi *intf,
 		 * causes it to not be freed or queued.
 		 */
 		rv = -1;
-	} else {
-		recv_msg = ipmi_alloc_recv_msg();
-		if (!recv_msg) {
-			/*
-			 * We couldn't allocate memory for the
-			 * message, so requeue it for handling later.
-			 */
-			rv = 1;
-			kref_put(&user->refcount, free_ipmi_user);
-		} else {
-			/* Extract the source address from the data. */
-			lan_addr = (struct ipmi_lan_addr *) &recv_msg->addr;
-			lan_addr->addr_type = IPMI_LAN_ADDR_TYPE;
-			lan_addr->session_handle = msg->rsp[4];
-			lan_addr->remote_SWID = msg->rsp[8];
-			lan_addr->local_SWID = msg->rsp[5];
-			lan_addr->lun = msg->rsp[9] & 3;
-			lan_addr->channel = msg->rsp[3] & 0xf;
-			lan_addr->privilege = msg->rsp[3] >> 4;
+	} else if (!IS_ERR(recv_msg)) {
+		/* Extract the source address from the data. */
+		lan_addr = (struct ipmi_lan_addr *) &recv_msg->addr;
+		lan_addr->addr_type = IPMI_LAN_ADDR_TYPE;
+		lan_addr->session_handle = msg->rsp[4];
+		lan_addr->remote_SWID = msg->rsp[8];
+		lan_addr->local_SWID = msg->rsp[5];
+		lan_addr->lun = msg->rsp[9] & 3;
+		lan_addr->channel = msg->rsp[3] & 0xf;
+		lan_addr->privilege = msg->rsp[3] >> 4;
 
-			/*
-			 * Extract the rest of the message information
-			 * from the IPMB header.
-			 */
-			recv_msg->user = user;
-			recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
-			recv_msg->msgid = msg->rsp[9] >> 2;
-			recv_msg->msg.netfn = msg->rsp[6] >> 2;
-			recv_msg->msg.cmd = msg->rsp[10];
-			recv_msg->msg.data = recv_msg->msg_data;
+		/*
+		 * Extract the rest of the message information
+		 * from the IPMB header.
+		 */
+		recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
+		recv_msg->msgid = msg->rsp[9] >> 2;
+		recv_msg->msg.netfn = msg->rsp[6] >> 2;
+		recv_msg->msg.cmd = msg->rsp[10];
+		recv_msg->msg.data = recv_msg->msg_data;
 
-			/*
-			 * We chop off 12, not 11 bytes because the checksum
-			 * at the end also needs to be removed.
-			 */
-			recv_msg->msg.data_len = msg->rsp_size - 12;
-			memcpy(recv_msg->msg_data, &msg->rsp[11],
-			       msg->rsp_size - 12);
-			if (deliver_response(intf, recv_msg))
-				ipmi_inc_stat(intf, unhandled_commands);
-			else
-				ipmi_inc_stat(intf, handled_commands);
-		}
+		/*
+		 * We chop off 12, not 11 bytes because the checksum
+		 * at the end also needs to be removed.
+		 */
+		recv_msg->msg.data_len = msg->rsp_size - 12;
+		memcpy(recv_msg->msg_data, &msg->rsp[11],
+		       msg->rsp_size - 12);
+		if (deliver_response(intf, recv_msg))
+			ipmi_inc_stat(intf, unhandled_commands);
+		else
+			ipmi_inc_stat(intf, handled_commands);
+	} else {
+		/*
+		 * We couldn't allocate memory for the message, so
+		 * requeue it for handling later.
+		 */
+		rv = 1;
 	}
 
 	return rv;
@@ -4270,7 +4280,7 @@ static int handle_oem_get_msg_cmd(struct ipmi_smi *intf,
 	unsigned char         chan;
 	struct ipmi_user *user = NULL;
 	struct ipmi_system_interface_addr *smi_addr;
-	struct ipmi_recv_msg  *recv_msg;
+	struct ipmi_recv_msg  *recv_msg = NULL;
 
 	/*
 	 * We expect the OEM SW to perform error checking
@@ -4299,9 +4309,8 @@ static int handle_oem_get_msg_cmd(struct ipmi_smi *intf,
 	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
 	if (rcvr) {
 		user = rcvr->user;
-		kref_get(&user->refcount);
-	} else
-		user = NULL;
+		recv_msg = ipmi_alloc_recv_msg(user);
+	}
 	rcu_read_unlock();
 
 	if (user == NULL) {
@@ -4314,48 +4323,42 @@ static int handle_oem_get_msg_cmd(struct ipmi_smi *intf,
 		 */
 
 		rv = 0;
-	} else {
-		recv_msg = ipmi_alloc_recv_msg();
-		if (!recv_msg) {
-			/*
-			 * We couldn't allocate memory for the
-			 * message, so requeue it for handling
-			 * later.
-			 */
-			rv = 1;
-			kref_put(&user->refcount, free_ipmi_user);
-		} else {
-			/*
-			 * OEM Messages are expected to be delivered via
-			 * the system interface to SMS software.  We might
-			 * need to visit this again depending on OEM
-			 * requirements
-			 */
-			smi_addr = ((struct ipmi_system_interface_addr *)
-				    &recv_msg->addr);
-			smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
-			smi_addr->channel = IPMI_BMC_CHANNEL;
-			smi_addr->lun = msg->rsp[0] & 3;
-
-			recv_msg->user = user;
-			recv_msg->user_msg_data = NULL;
-			recv_msg->recv_type = IPMI_OEM_RECV_TYPE;
-			recv_msg->msg.netfn = msg->rsp[0] >> 2;
-			recv_msg->msg.cmd = msg->rsp[1];
-			recv_msg->msg.data = recv_msg->msg_data;
+	} else if (!IS_ERR(recv_msg)) {
+		/*
+		 * OEM Messages are expected to be delivered via
+		 * the system interface to SMS software.  We might
+		 * need to visit this again depending on OEM
+		 * requirements
+		 */
+		smi_addr = ((struct ipmi_system_interface_addr *)
+			    &recv_msg->addr);
+		smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+		smi_addr->channel = IPMI_BMC_CHANNEL;
+		smi_addr->lun = msg->rsp[0] & 3;
+
+		recv_msg->user_msg_data = NULL;
+		recv_msg->recv_type = IPMI_OEM_RECV_TYPE;
+		recv_msg->msg.netfn = msg->rsp[0] >> 2;
+		recv_msg->msg.cmd = msg->rsp[1];
+		recv_msg->msg.data = recv_msg->msg_data;
 
-			/*
-			 * The message starts at byte 4 which follows the
-			 * Channel Byte in the "GET MESSAGE" command
-			 */
-			recv_msg->msg.data_len = msg->rsp_size - 4;
-			memcpy(recv_msg->msg_data, &msg->rsp[4],
-			       msg->rsp_size - 4);
-			if (deliver_response(intf, recv_msg))
-				ipmi_inc_stat(intf, unhandled_commands);
-			else
-				ipmi_inc_stat(intf, handled_commands);
-		}
+		/*
+		 * The message starts at byte 4 which follows the
+		 * Channel Byte in the "GET MESSAGE" command
+		 */
+		recv_msg->msg.data_len = msg->rsp_size - 4;
+		memcpy(recv_msg->msg_data, &msg->rsp[4],
+		       msg->rsp_size - 4);
+		if (deliver_response(intf, recv_msg))
+			ipmi_inc_stat(intf, unhandled_commands);
+		else
+			ipmi_inc_stat(intf, handled_commands);
+	} else {
+		/*
+		 * We couldn't allocate memory for the message, so
+		 * requeue it for handling later.
+		 */
+		rv = 1;
 	}
 
 	return rv;
@@ -4413,8 +4416,8 @@ static int handle_read_event_rsp(struct ipmi_smi *intf,
 		if (!user->gets_events)
 			continue;
 
-		recv_msg = ipmi_alloc_recv_msg();
-		if (!recv_msg) {
+		recv_msg = ipmi_alloc_recv_msg(user);
+		if (IS_ERR(recv_msg)) {
 			mutex_unlock(&intf->users_mutex);
 			list_for_each_entry_safe(recv_msg, recv_msg2, &msgs,
 						 link) {
@@ -4435,8 +4438,6 @@ static int handle_read_event_rsp(struct ipmi_smi *intf,
 		deliver_count++;
 
 		copy_event_into_recv_msg(recv_msg, msg);
-		recv_msg->user = user;
-		kref_get(&user->refcount);
 		list_add_tail(&recv_msg->link, &msgs);
 	}
 	mutex_unlock(&intf->users_mutex);
@@ -4452,8 +4453,8 @@ static int handle_read_event_rsp(struct ipmi_smi *intf,
 		 * No one to receive the message, put it in queue if there's
 		 * not already too many things in the queue.
 		 */
-		recv_msg = ipmi_alloc_recv_msg();
-		if (!recv_msg) {
+		recv_msg = ipmi_alloc_recv_msg(NULL);
+		if (IS_ERR(recv_msg)) {
 			/*
 			 * We couldn't allocate memory for the
 			 * message, so requeue it for handling
@@ -4488,7 +4489,7 @@ static int handle_bmc_rsp(struct ipmi_smi *intf,
 	struct ipmi_recv_msg *recv_msg;
 	struct ipmi_system_interface_addr *smi_addr;
 
-	recv_msg = msg->user_data;
+	recv_msg = msg->recv_msg;
 	if (recv_msg == NULL) {
 		dev_warn(intf->si_dev,
 			 "IPMI SMI message received with no owner. This could be because of a malformed message, or because of a hardware error.  Contact your hardware vendor for assistance.\n");
@@ -4529,9 +4530,10 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
 
 	if (msg->rsp_size < 2) {
 		/* Message is too small to be correct. */
-		dev_warn(intf->si_dev,
-			 "BMC returned too small a message for netfn %x cmd %x, got %d bytes\n",
-			 (msg->data[0] >> 2) | 1, msg->data[1], msg->rsp_size);
+		dev_warn_ratelimited(intf->si_dev,
+				     "BMC returned too small a message for netfn %x cmd %x, got %d bytes\n",
+				     (msg->data[0] >> 2) | 1,
+				     msg->data[1], msg->rsp_size);
 
 return_unspecified:
 		/* Generate an error response for the message. */
@@ -4561,14 +4563,14 @@ return_unspecified:
 	} else if ((msg->data_size >= 2)
 	    && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
 	    && (msg->data[1] == IPMI_SEND_MSG_CMD)
-	    && (msg->user_data == NULL)) {
+	    && (msg->recv_msg == NULL)) {
 
 		if (intf->in_shutdown || intf->run_to_completion)
 			goto out;
 
 		/*
 		 * This is the local response to a command send, start
-		 * the timer for these.  The user_data will not be
+		 * the timer for these.  The recv_msg will not be
 		 * NULL if this is a response send, and we will let
 		 * response sends just go through.
 		 */
@@ -4628,7 +4630,7 @@ return_unspecified:
 			requeue = handle_ipmb_direct_rcv_rsp(intf, msg);
 	} else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
 		   && (msg->rsp[1] == IPMI_SEND_MSG_CMD)
-		   && (msg->user_data != NULL)) {
+		   && (msg->recv_msg != NULL)) {
 		/*
 		 * It's a response to a response we sent.  For this we
 		 * deliver a send message response to the user.
@@ -4645,7 +4647,7 @@ return_unspecified:
 		cc = msg->rsp[2];
 
 process_response_response:
-		recv_msg = msg->user_data;
+		recv_msg = msg->recv_msg;
 
 		requeue = 0;
 		if (!recv_msg)
@@ -4801,6 +4803,7 @@ static void smi_work(struct work_struct *t)
 	int run_to_completion = READ_ONCE(intf->run_to_completion);
 	struct ipmi_smi_msg *newmsg = NULL;
 	struct ipmi_recv_msg *msg, *msg2;
+	int cc;
 
 	/*
 	 * Start the next message if available.
@@ -4809,7 +4812,7 @@ static void smi_work(struct work_struct *t)
 	 * because the lower layer is allowed to hold locks while calling
 	 * message delivery.
 	 */
-
+restart:
 	if (!run_to_completion)
 		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
 	if (intf->curr_msg == NULL && !intf->in_shutdown) {
@@ -4830,8 +4833,17 @@ static void smi_work(struct work_struct *t)
 	if (!run_to_completion)
 		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
 
-	if (newmsg)
-		intf->handlers->sender(intf->send_info, newmsg);
+	if (newmsg) {
+		cc = intf->handlers->sender(intf->send_info, newmsg);
+		if (cc) {
+			if (newmsg->recv_msg)
+				deliver_err_response(intf,
+						     newmsg->recv_msg, cc);
+			else
+				ipmi_free_smi_msg(newmsg);
+			goto restart;
+		}
+	}
 
 	handle_new_recv_msgs(intf);
 
@@ -4868,12 +4880,10 @@ static void smi_work(struct work_struct *t)
 
 		list_del(&msg->link);
 
-		if (refcount_read(&user->destroyed) == 0) {
+		if (refcount_read(&user->destroyed) == 0)
 			ipmi_free_recv_msg(msg);
-		} else {
-			atomic_dec(&user->nr_msgs);
+		else
 			user->handler->ipmi_recv_hndl(msg, user->handler_data);
-		}
 	}
 	mutex_unlock(&intf->user_msgs_mutex);
 
@@ -4951,8 +4961,7 @@ smi_from_recv_msg(struct ipmi_smi *intf, struct ipmi_recv_msg *recv_msg,
 static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 			      struct list_head *timeouts,
 			      unsigned long timeout_period,
-			      int slot, unsigned long *flags,
-			      bool *need_timer)
+			      int slot, bool *need_timer)
 {
 	struct ipmi_recv_msg *msg;
 
@@ -5004,7 +5013,7 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 			return;
 		}
 
-		spin_unlock_irqrestore(&intf->seq_lock, *flags);
+		mutex_unlock(&intf->seq_lock);
 
 		/*
 		 * Send the new message.  We send with a zero
@@ -5025,7 +5034,7 @@ static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
 		} else
 			ipmi_free_smi_msg(smi_msg);
 
-		spin_lock_irqsave(&intf->seq_lock, *flags);
+		mutex_lock(&intf->seq_lock);
 	}
 }
 
@@ -5052,7 +5061,7 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
 	 * list.
 	 */
 	INIT_LIST_HEAD(&timeouts);
-	spin_lock_irqsave(&intf->seq_lock, flags);
+	mutex_lock(&intf->seq_lock);
 	if (intf->ipmb_maintenance_mode_timeout) {
 		if (intf->ipmb_maintenance_mode_timeout <= timeout_period)
 			intf->ipmb_maintenance_mode_timeout = 0;
@@ -5062,8 +5071,8 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
 	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++)
 		check_msg_timeout(intf, &intf->seq_table[i],
 				  &timeouts, timeout_period, i,
-				  &flags, &need_timer);
-	spin_unlock_irqrestore(&intf->seq_lock, flags);
+				  &need_timer);
+	mutex_unlock(&intf->seq_lock);
 
 	list_for_each_entry_safe(msg, msg2, &timeouts, link)
 		deliver_err_response(intf, msg, IPMI_TIMEOUT_COMPLETION_CODE);
@@ -5083,7 +5092,9 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
 				-= timeout_period;
 			if (!intf->maintenance_mode
 			    && (intf->auto_maintenance_timeout <= 0)) {
-				intf->maintenance_mode_enable = false;
+				intf->maintenance_mode_state =
+					IPMI_MAINTENANCE_MODE_STATE_OFF;
+				intf->auto_maintenance_timeout = 0;
 				maintenance_mode_update(intf);
 			}
 		}
@@ -5099,15 +5110,13 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
 static void ipmi_request_event(struct ipmi_smi *intf)
 {
 	/* No event requests when in maintenance mode. */
-	if (intf->maintenance_mode_enable)
+	if (intf->maintenance_mode_state)
 		return;
 
 	if (!intf->in_shutdown)
 		intf->handlers->request_events(intf->send_info);
 }
 
-static struct timer_list ipmi_timer;
-
 static atomic_t stop_operation;
 
 static void ipmi_timeout_work(struct work_struct *work)
@@ -5131,6 +5140,8 @@ static void ipmi_timeout_work(struct work_struct *work)
 			}
 			need_timer = true;
 		}
+		if (intf->maintenance_mode_state)
+			need_timer = true;
 
 		need_timer |= ipmi_timeout_handler(intf, IPMI_TIMEOUT_TIME);
 	}
@@ -5174,7 +5185,7 @@ struct ipmi_smi_msg *ipmi_alloc_smi_msg(void)
 	rv = kmalloc(sizeof(struct ipmi_smi_msg), GFP_ATOMIC);
 	if (rv) {
 		rv->done = free_smi_msg;
-		rv->user_data = NULL;
+		rv->recv_msg = NULL;
 		rv->type = IPMI_SMI_MSG_TYPE_NORMAL;
 		atomic_inc(&smi_msg_inuse_count);
 	}
@@ -5190,27 +5201,51 @@ static void free_recv_msg(struct ipmi_recv_msg *msg)
 		kfree(msg);
 }
 
-static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
+static struct ipmi_recv_msg *ipmi_alloc_recv_msg(struct ipmi_user *user)
 {
 	struct ipmi_recv_msg *rv;
 
+	if (user) {
+		if (atomic_add_return(1, &user->nr_msgs) > max_msgs_per_user) {
+			atomic_dec(&user->nr_msgs);
+			return ERR_PTR(-EBUSY);
+		}
+	}
+
 	rv = kmalloc(sizeof(struct ipmi_recv_msg), GFP_ATOMIC);
-	if (rv) {
-		rv->user = NULL;
-		rv->done = free_recv_msg;
-		atomic_inc(&recv_msg_inuse_count);
+	if (!rv) {
+		if (user)
+			atomic_dec(&user->nr_msgs);
+		return ERR_PTR(-ENOMEM);
 	}
+
+	rv->user = user;
+	rv->done = free_recv_msg;
+	if (user)
+		kref_get(&user->refcount);
+	atomic_inc(&recv_msg_inuse_count);
 	return rv;
 }
 
 void ipmi_free_recv_msg(struct ipmi_recv_msg *msg)
 {
-	if (msg->user && !oops_in_progress)
+	if (msg->user && !oops_in_progress) {
+		atomic_dec(&msg->user->nr_msgs);
 		kref_put(&msg->user->refcount, free_ipmi_user);
+	}
 	msg->done(msg);
 }
 EXPORT_SYMBOL(ipmi_free_recv_msg);
 
+static void ipmi_set_recv_msg_user(struct ipmi_recv_msg *msg,
+				   struct ipmi_user *user)
+{
+	WARN_ON_ONCE(msg->user); /* User should not be set. */
+	msg->user = user;
+	atomic_inc(&user->nr_msgs);
+	kref_get(&user->refcount);
+}
+
 static atomic_t panic_done_count = ATOMIC_INIT(0);
 
 static void dummy_smi_done_handler(struct ipmi_smi_msg *msg)
diff --git a/drivers/char/ipmi/ipmi_powernv.c b/drivers/char/ipmi/ipmi_powernv.c
index 4a2efafcd1f8..52a1130defe5 100644
--- a/drivers/char/ipmi/ipmi_powernv.c
+++ b/drivers/char/ipmi/ipmi_powernv.c
@@ -51,7 +51,7 @@ static void send_error_reply(struct ipmi_smi_powernv *smi,
 	ipmi_smi_msg_received(smi->intf, msg);
 }
 
-static void ipmi_powernv_send(void *send_info, struct ipmi_smi_msg *msg)
+static int ipmi_powernv_send(void *send_info, struct ipmi_smi_msg *msg)
 {
 	struct ipmi_smi_powernv *smi = send_info;
 	struct opal_ipmi_msg *opal_msg;
@@ -93,18 +93,19 @@ static void ipmi_powernv_send(void *send_info, struct ipmi_smi_msg *msg)
 			smi->interface_id, opal_msg, size);
 	rc = opal_ipmi_send(smi->interface_id, opal_msg, size);
 	pr_devel("%s:  -> %d\n", __func__, rc);
-
-	if (!rc) {
-		smi->cur_msg = msg;
-		spin_unlock_irqrestore(&smi->msg_lock, flags);
-		return;
+	if (rc) {
+		comp = IPMI_ERR_UNSPECIFIED;
+		goto err_unlock;
 	}
 
-	comp = IPMI_ERR_UNSPECIFIED;
+	smi->cur_msg = msg;
+	spin_unlock_irqrestore(&smi->msg_lock, flags);
+	return IPMI_CC_NO_ERROR;
+
 err_unlock:
 	spin_unlock_irqrestore(&smi->msg_lock, flags);
 err:
-	send_error_reply(smi, msg, comp);
+	return comp;
 }
 
 static int ipmi_powernv_recv(struct ipmi_smi_powernv *smi)
diff --git a/drivers/char/ipmi/ipmi_si.h b/drivers/char/ipmi/ipmi_si.h
index 508c3fd45877..687835b53da5 100644
--- a/drivers/char/ipmi/ipmi_si.h
+++ b/drivers/char/ipmi/ipmi_si.h
@@ -101,6 +101,13 @@ void ipmi_si_pci_shutdown(void);
 static inline void ipmi_si_pci_init(void) { }
 static inline void ipmi_si_pci_shutdown(void) { }
 #endif
+#ifdef CONFIG_IPMI_LS2K
+void ipmi_si_ls2k_init(void);
+void ipmi_si_ls2k_shutdown(void);
+#else
+static inline void ipmi_si_ls2k_init(void) { }
+static inline void ipmi_si_ls2k_shutdown(void) { }
+#endif
 #ifdef CONFIG_PARISC
 void ipmi_si_parisc_init(void);
 void ipmi_si_parisc_shutdown(void);
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 8b5524069c15..70e55f5ff85e 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -53,6 +53,7 @@
 #define SI_TIMEOUT_JIFFIES	(SI_TIMEOUT_TIME_USEC/SI_USEC_PER_JIFFY)
 #define SI_SHORT_TIMEOUT_USEC  250 /* .25ms when the SM request a
 				      short timeout */
+#define SI_TIMEOUT_HOSED	(HZ) /* 1 second when in hosed state. */
 
 enum si_intf_state {
 	SI_NORMAL,
@@ -61,7 +62,8 @@ enum si_intf_state {
 	SI_CLEARING_FLAGS,
 	SI_GETTING_MESSAGES,
 	SI_CHECKING_ENABLES,
-	SI_SETTING_ENABLES
+	SI_SETTING_ENABLES,
+	SI_HOSED
 	/* FIXME - add watchdog stuff. */
 };
 
@@ -313,7 +315,7 @@ static void return_hosed_msg(struct smi_info *smi_info, int cCode)
 
 static enum si_sm_result start_next_msg(struct smi_info *smi_info)
 {
-	int              rv;
+	int rv;
 
 	if (!smi_info->waiting_msg) {
 		smi_info->curr_msg = NULL;
@@ -390,6 +392,17 @@ static void start_clear_flags(struct smi_info *smi_info)
 	smi_info->si_state = SI_CLEARING_FLAGS;
 }
 
+static void start_get_flags(struct smi_info *smi_info)
+{
+	unsigned char msg[2];
+
+	msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
+	msg[1] = IPMI_GET_MSG_FLAGS_CMD;
+
+	start_new_msg(smi_info, msg, 2);
+	smi_info->si_state = SI_GETTING_FLAGS;
+}
+
 static void start_getting_msg_queue(struct smi_info *smi_info)
 {
 	smi_info->curr_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
@@ -742,6 +755,8 @@ static void handle_transaction_done(struct smi_info *smi_info)
 		}
 		break;
 	}
+	case SI_HOSED: /* Shouldn't happen. */
+		break;
 	}
 }
 
@@ -756,6 +771,10 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
 	enum si_sm_result si_sm_result;
 
 restart:
+	if (smi_info->si_state == SI_HOSED)
+		/* Just in case, hosed state is only left from the timeout. */
+		return SI_SM_HOSED;
+
 	/*
 	 * There used to be a loop here that waited a little while
 	 * (around 25us) before giving up.  That turned out to be
@@ -779,18 +798,20 @@ restart:
 
 		/*
 		 * Do the before return_hosed_msg, because that
-		 * releases the lock.
+		 * releases the lock.  We just disable operations for
+		 * a while and retry in hosed state.
 		 */
-		smi_info->si_state = SI_NORMAL;
+		smi_info->si_state = SI_HOSED;
 		if (smi_info->curr_msg != NULL) {
 			/*
 			 * If we were handling a user message, format
 			 * a response to send to the upper layer to
 			 * tell it about the error.
 			 */
-			return_hosed_msg(smi_info, IPMI_ERR_UNSPECIFIED);
+			return_hosed_msg(smi_info, IPMI_BUS_ERR);
 		}
-		goto restart;
+		smi_mod_timer(smi_info, jiffies + SI_TIMEOUT_HOSED);
+		goto out;
 	}
 
 	/*
@@ -798,8 +819,6 @@ restart:
 	 * this if there is not yet an upper layer to handle anything.
 	 */
 	if (si_sm_result == SI_SM_ATTN || smi_info->got_attn) {
-		unsigned char msg[2];
-
 		if (smi_info->si_state != SI_NORMAL) {
 			/*
 			 * We got an ATTN, but we are doing something else.
@@ -817,11 +836,7 @@ restart:
 			 * interrupts work with the SMI, that's not really
 			 * possible.
 			 */
-			msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
-			msg[1] = IPMI_GET_MSG_FLAGS_CMD;
-
-			start_new_msg(smi_info, msg, 2);
-			smi_info->si_state = SI_GETTING_FLAGS;
+			start_get_flags(smi_info);
 			goto restart;
 		}
 	}
@@ -894,27 +909,29 @@ static void flush_messages(void *send_info)
 	 * mode.  This means we are single-threaded, no need for locks.
 	 */
 	result = smi_event_handler(smi_info, 0);
-	while (result != SI_SM_IDLE) {
+	while (result != SI_SM_IDLE && result != SI_SM_HOSED) {
 		udelay(SI_SHORT_TIMEOUT_USEC);
 		result = smi_event_handler(smi_info, SI_SHORT_TIMEOUT_USEC);
 	}
 }
 
-static void sender(void                *send_info,
-		   struct ipmi_smi_msg *msg)
+static int sender(void *send_info, struct ipmi_smi_msg *msg)
 {
 	struct smi_info   *smi_info = send_info;
 	unsigned long     flags;
 
 	debug_timestamp(smi_info, "Enqueue");
 
+	if (smi_info->si_state == SI_HOSED)
+		return IPMI_BUS_ERR;
+
 	if (smi_info->run_to_completion) {
 		/*
 		 * If we are running to completion, start it.  Upper
 		 * layer will call flush_messages to clear it out.
 		 */
 		smi_info->waiting_msg = msg;
-		return;
+		return IPMI_CC_NO_ERROR;
 	}
 
 	spin_lock_irqsave(&smi_info->si_lock, flags);
@@ -929,6 +946,7 @@ static void sender(void                *send_info,
 	smi_info->waiting_msg = msg;
 	check_start_timer_thread(smi_info);
 	spin_unlock_irqrestore(&smi_info->si_lock, flags);
+	return IPMI_CC_NO_ERROR;
 }
 
 static void set_run_to_completion(void *send_info, bool i_run_to_completion)
@@ -1087,6 +1105,10 @@ static void smi_timeout(struct timer_list *t)
 	spin_lock_irqsave(&(smi_info->si_lock), flags);
 	debug_timestamp(smi_info, "Timer");
 
+	if (smi_info->si_state == SI_HOSED)
+		/* Try something to see if the BMC is now operational. */
+		start_get_flags(smi_info);
+
 	jiffies_now = jiffies;
 	time_diff = (((long)jiffies_now - (long)smi_info->last_timeout_jiffies)
 		     * SI_USEC_PER_JIFFY);
@@ -1096,14 +1118,11 @@ static void smi_timeout(struct timer_list *t)
 		/* Running with interrupts, only do long timeouts. */
 		timeout = jiffies + SI_TIMEOUT_JIFFIES;
 		smi_inc_stat(smi_info, long_timeouts);
-		goto do_mod_timer;
-	}
-
-	/*
-	 * If the state machine asks for a short delay, then shorten
-	 * the timer timeout.
-	 */
-	if (smi_result == SI_SM_CALL_WITH_DELAY) {
+	} else if (smi_result == SI_SM_CALL_WITH_DELAY) {
+		/*
+		 * If the state machine asks for a short delay, then shorten
+		 * the timer timeout.
+		 */
 		smi_inc_stat(smi_info, short_timeouts);
 		timeout = jiffies + 1;
 	} else {
@@ -1111,7 +1130,6 @@ static void smi_timeout(struct timer_list *t)
 		timeout = jiffies + SI_TIMEOUT_JIFFIES;
 	}
 
-do_mod_timer:
 	if (smi_result != SI_SM_IDLE)
 		smi_mod_timer(smi_info, timeout);
 	else
@@ -2120,6 +2138,8 @@ static int __init init_ipmi_si(void)
 
 	ipmi_si_pci_init();
 
+	ipmi_si_ls2k_init();
+
 	ipmi_si_parisc_init();
 
 	mutex_lock(&smi_infos_lock);
@@ -2331,6 +2351,8 @@ static void cleanup_ipmi_si(void)
 
 	ipmi_si_pci_shutdown();
 
+	ipmi_si_ls2k_shutdown();
+
 	ipmi_si_parisc_shutdown();
 
 	ipmi_si_platform_shutdown();
diff --git a/drivers/char/ipmi/ipmi_si_ls2k.c b/drivers/char/ipmi/ipmi_si_ls2k.c
new file mode 100644
index 000000000000..45442c257efd
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_si_ls2k.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Loongson-2K BMC IPMI interface
+ *
+ * Copyright (C) 2024-2025 Loongson Technology Corporation Limited.
+ *
+ * Authors:
+ *	Chong Qiao <qiaochong@loongson.cn>
+ *	Binbin Zhou <zhoubinbin@loongson.cn>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include "ipmi_si.h"
+
+#define LS2K_KCS_FIFO_IBFH	0x0
+#define LS2K_KCS_FIFO_IBFT	0x1
+#define LS2K_KCS_FIFO_OBFH	0x2
+#define LS2K_KCS_FIFO_OBFT	0x3
+
+/* KCS registers */
+#define LS2K_KCS_REG_STS	0x4
+#define LS2K_KCS_REG_DATA_OUT	0x5
+#define LS2K_KCS_REG_DATA_IN	0x6
+#define LS2K_KCS_REG_CMD	0x8
+
+#define LS2K_KCS_CMD_DATA	0xa
+#define LS2K_KCS_VERSION	0xb
+#define LS2K_KCS_WR_REQ		0xc
+#define LS2K_KCS_WR_ACK		0x10
+
+#define LS2K_KCS_STS_OBF	BIT(0)
+#define LS2K_KCS_STS_IBF	BIT(1)
+#define LS2K_KCS_STS_SMS_ATN	BIT(2)
+#define LS2K_KCS_STS_CMD	BIT(3)
+
+#define LS2K_KCS_DATA_MASK	(LS2K_KCS_STS_OBF | LS2K_KCS_STS_IBF | LS2K_KCS_STS_CMD)
+
+static bool ls2k_registered;
+
+static unsigned char ls2k_mem_inb_v0(const struct si_sm_io *io, unsigned int offset)
+{
+	void __iomem *addr = io->addr;
+	int reg_offset;
+
+	if (offset & BIT(0)) {
+		reg_offset = LS2K_KCS_REG_STS;
+	} else {
+		writeb(readb(addr + LS2K_KCS_REG_STS) & ~LS2K_KCS_STS_OBF, addr + LS2K_KCS_REG_STS);
+		reg_offset = LS2K_KCS_REG_DATA_OUT;
+	}
+
+	return readb(addr + reg_offset);
+}
+
+static unsigned char ls2k_mem_inb_v1(const struct si_sm_io *io, unsigned int offset)
+{
+	void __iomem *addr = io->addr;
+	unsigned char inb = 0, cmd;
+	bool obf, ibf;
+
+	obf = readb(addr + LS2K_KCS_FIFO_OBFH) ^ readb(addr + LS2K_KCS_FIFO_OBFT);
+	ibf = readb(addr + LS2K_KCS_FIFO_IBFH) ^ readb(addr + LS2K_KCS_FIFO_IBFT);
+	cmd = readb(addr + LS2K_KCS_CMD_DATA);
+
+	if (offset & BIT(0)) {
+		inb = readb(addr + LS2K_KCS_REG_STS) & ~LS2K_KCS_DATA_MASK;
+		inb |= FIELD_PREP(LS2K_KCS_STS_OBF, obf)
+		    | FIELD_PREP(LS2K_KCS_STS_IBF, ibf)
+		    | FIELD_PREP(LS2K_KCS_STS_CMD, cmd);
+	} else {
+		inb = readb(addr + LS2K_KCS_REG_DATA_OUT);
+		writeb(readb(addr + LS2K_KCS_FIFO_OBFH), addr + LS2K_KCS_FIFO_OBFT);
+	}
+
+	return inb;
+}
+
+static void ls2k_mem_outb_v0(const struct si_sm_io *io, unsigned int offset,
+			     unsigned char val)
+{
+	void __iomem *addr = io->addr;
+	unsigned char sts = readb(addr + LS2K_KCS_REG_STS);
+	int reg_offset;
+
+	if (sts & LS2K_KCS_STS_IBF)
+		return;
+
+	if (offset & BIT(0)) {
+		reg_offset = LS2K_KCS_REG_CMD;
+		sts |= LS2K_KCS_STS_CMD;
+	} else {
+		reg_offset = LS2K_KCS_REG_DATA_IN;
+		sts &= ~LS2K_KCS_STS_CMD;
+	}
+
+	writew(val, addr + reg_offset);
+	writeb(sts | LS2K_KCS_STS_IBF, addr + LS2K_KCS_REG_STS);
+	writel(readl(addr + LS2K_KCS_WR_REQ) + 1, addr + LS2K_KCS_WR_REQ);
+}
+
+static void ls2k_mem_outb_v1(const struct si_sm_io *io, unsigned int offset,
+			     unsigned char val)
+{
+	void __iomem *addr = io->addr;
+	unsigned char ibfh, ibft;
+	int reg_offset;
+
+	ibfh = readb(addr + LS2K_KCS_FIFO_IBFH);
+	ibft = readb(addr + LS2K_KCS_FIFO_IBFT);
+
+	if (ibfh ^ ibft)
+		return;
+
+	reg_offset = (offset & BIT(0)) ? LS2K_KCS_REG_CMD : LS2K_KCS_REG_DATA_IN;
+	writew(val, addr + reg_offset);
+
+	writeb(offset & BIT(0), addr + LS2K_KCS_CMD_DATA);
+	writeb(!ibft, addr + LS2K_KCS_FIFO_IBFH);
+	writel(readl(addr + LS2K_KCS_WR_REQ) + 1, addr + LS2K_KCS_WR_REQ);
+}
+
+static void ls2k_mem_cleanup(struct si_sm_io *io)
+{
+	if (io->addr)
+		iounmap(io->addr);
+}
+
+static int ipmi_ls2k_mem_setup(struct si_sm_io *io)
+{
+	unsigned char version;
+
+	io->addr = ioremap(io->addr_data, io->regspacing);
+	if (!io->addr)
+		return -EIO;
+
+	version = readb(io->addr + LS2K_KCS_VERSION);
+
+	io->inputb = version ? ls2k_mem_inb_v1 : ls2k_mem_inb_v0;
+	io->outputb = version ? ls2k_mem_outb_v1 : ls2k_mem_outb_v0;
+	io->io_cleanup = ls2k_mem_cleanup;
+
+	return 0;
+}
+
+static int ipmi_ls2k_probe(struct platform_device *pdev)
+{
+	struct si_sm_io io;
+
+	memset(&io, 0, sizeof(io));
+
+	io.si_info	= &ipmi_kcs_si_info;
+	io.io_setup	= ipmi_ls2k_mem_setup;
+	io.addr_data	= pdev->resource[0].start;
+	io.regspacing	= resource_size(&pdev->resource[0]);
+	io.dev		= &pdev->dev;
+
+	dev_dbg(&pdev->dev, "addr 0x%lx, spacing %d.\n", io.addr_data, io.regspacing);
+
+	return ipmi_si_add_smi(&io);
+}
+
+static void ipmi_ls2k_remove(struct platform_device *pdev)
+{
+	ipmi_si_remove_by_dev(&pdev->dev);
+}
+
+struct platform_driver ipmi_ls2k_platform_driver = {
+	.driver = {
+		.name = "ls2k-ipmi-si",
+	},
+	.probe	= ipmi_ls2k_probe,
+	.remove	= ipmi_ls2k_remove,
+};
+
+void ipmi_si_ls2k_init(void)
+{
+	platform_driver_register(&ipmi_ls2k_platform_driver);
+	ls2k_registered = true;
+}
+
+void ipmi_si_ls2k_shutdown(void)
+{
+	if (ls2k_registered)
+		platform_driver_unregister(&ipmi_ls2k_platform_driver);
+}
diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 1bc42830444d..1b63f7d2fcda 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1068,8 +1068,7 @@ static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags)
 	}
 }
 
-static void sender(void                *send_info,
-		   struct ipmi_smi_msg *msg)
+static int sender(void *send_info, struct ipmi_smi_msg *msg)
 {
 	struct ssif_info *ssif_info = send_info;
 	unsigned long oflags, *flags;
@@ -1089,6 +1088,7 @@ static void sender(void                *send_info,
 			msg->data[0], msg->data[1],
 			(long long)t.tv_sec, (long)t.tv_nsec / NSEC_PER_USEC);
 	}
+	return IPMI_CC_NO_ERROR;
 }
 
 static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
index 5d69820d8b02..892e2d656e1e 100644
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -109,8 +109,9 @@ struct ipmi_smi_msg {
 
 	enum ipmi_smi_msg_type type;
 
-	long    msgid;
-	void    *user_data;
+	long msgid;
+	/* Response to this message, will be NULL if not from a user request. */
+	struct ipmi_recv_msg *recv_msg;
 
 	int           data_size;
 	unsigned char data[IPMI_MAX_MSG_LENGTH];
@@ -168,9 +169,11 @@ struct ipmi_smi_handlers {
 	 * are held when this is run.  Message are delivered one at
 	 * a time by the message handler, a new message will not be
 	 * delivered until the previous message is returned.
+	 *
+	 * This can return an error if the SMI is not in a state where it
+	 * can send a message.
 	 */
-	void (*sender)(void                *send_info,
-		       struct ipmi_smi_msg *msg);
+	int (*sender)(void *send_info, struct ipmi_smi_msg *msg);
 
 	/*
 	 * Called by the upper layer to request that we try to get