Bug fixes and enhancements for IPMI

This request 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.  There is a
 conflict in the MAINTAINERS file and the MFD tree changes must be
 there before this is applied.
 
 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.
 
 -corey
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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

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

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'

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

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)

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;
 	}
 

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)

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);

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 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
 
 		/*
 		 * 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 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
 	 * 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 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
 			 * 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();

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);
+}

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)

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