ipmi_msghandler.c

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/*
 * ipmi_msghandler.c
 *
 * Incoming and outgoing message routing for an IPMI interface.
 *
 * Author: MontaVista Software, Inc.
 *         Corey Minyard <[e-mail]>
 *         [e-mail]
 *
 * Copyright 2002 MontaVista Software Inc.
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the
 *  Free Software Foundation; either version 2 of the License, or (at your
 *  option) any later version.
 *
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 *  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 *  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <asm/system.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/ipmi.h>
#include <linux/ipmi_smi.h>
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/rcupdate.h>

#define PFX "IPMI message handler: "

#define IPMI_DRIVER_VERSION "39.1"

static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
static int ipmi_init_msghandler(void);

static int initialized;

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_ipmi_root;
#endif /* CONFIG_PROC_FS */

/* Remain in auto-maintenance mode for this amount of time (in ms). */
#define IPMI_MAINTENANCE_MODE_TIMEOUT 30000

#define MAX_EVENTS_IN_QUEUE	25

/* Don't let a message sit in a queue forever, always time it with at lest
   the max message timer.  This is in milliseconds. */
#define MAX_MSG_TIMEOUT		60000


/*
 * The main "user" data structure.
 */
struct ipmi_user
{
	struct list_head link;

	/* Set to "0" when the user is destroyed. */
	int valid;

	struct kref refcount;

	/* The upper layer that handles receive messages. */
	struct ipmi_user_hndl *handler;
	void             *handler_data;

	/* The interface this user is bound to. */
	ipmi_smi_t intf;

	/* Does this interface receive IPMI events? */
	int gets_events;
};

struct cmd_rcvr
{
	struct list_head link;

	ipmi_user_t   user;
	unsigned char netfn;
	unsigned char cmd;
	unsigned int  chans;

	/*
	 * This is used to form a linked lised during mass deletion.
	 * Since this is in an RCU list, we cannot use the link above
	 * or change any data until the RCU period completes.  So we
	 * use this next variable during mass deletion so we can have
	 * a list and don't have to wait and restart the search on
	 * every individual deletion of a command. */
	struct cmd_rcvr *next;
};

struct seq_table
{
	unsigned int         inuse : 1;
	unsigned int         broadcast : 1;

	unsigned long        timeout;
	unsigned long        orig_timeout;
	unsigned int         retries_left;

	/* To verify on an incoming send message response that this is
           the message that the response is for, we keep a sequence id
           and increment it every time we send a message. */
	long                 seqid;

	/* This is held so we can properly respond to the message on a
           timeout, and it is used to hold the temporary data for
           retransmission, too. */
	struct ipmi_recv_msg *recv_msg;
};

/* Store the information in a msgid (long) to allow us to find a
   sequence table entry from the msgid. */
#define STORE_SEQ_IN_MSGID(seq, seqid) (((seq&0xff)<<26) | (seqid&0x3ffffff))

#define GET_SEQ_FROM_MSGID(msgid, seq, seqid) \
	do {								\
		seq = ((msgid >> 26) & 0x3f);				\
		seqid = (msgid & 0x3fffff);				\
        } while (0)

#define NEXT_SEQID(seqid) (((seqid) + 1) & 0x3fffff)

struct ipmi_channel
{
	unsigned char medium;
	unsigned char protocol;

	/* My slave address.  This is initialized to IPMI_BMC_SLAVE_ADDR,
	   but may be changed by the user. */
	unsigned char address;

	/* My LUN.  This should generally stay the SMS LUN, but just in
	   case... */
	unsigned char lun;
};

#ifdef CONFIG_PROC_FS
struct ipmi_proc_entry
{
	char                   *name;
	struct ipmi_proc_entry *next;
};
#endif

struct bmc_device
{
	struct platform_device *dev;
	struct ipmi_device_id  id;
	unsigned char          guid[16];
	int                    guid_set;

	struct kref	       refcount;

	/* bmc device attributes */
	struct device_attribute device_id_attr;
	struct device_attribute provides_dev_sdrs_attr;
	struct device_attribute revision_attr;
	struct device_attribute firmware_rev_attr;
	struct device_attribute version_attr;
	struct device_attribute add_dev_support_attr;
	struct device_attribute manufacturer_id_attr;
	struct device_attribute product_id_attr;
	struct device_attribute guid_attr;
	struct device_attribute aux_firmware_rev_attr;
};

#define IPMI_IPMB_NUM_SEQ	64
#define IPMI_MAX_CHANNELS       16
struct ipmi_smi
{
	/* What interface number are we? */
	int intf_num;

	struct kref refcount;

	/* Used for a list of interfaces. */
	struct list_head link;

	/* The list of upper layers that are using me.  seq_lock
	 * protects this. */
	struct list_head users;

	/* Information to supply to users. */
	unsigned char ipmi_version_major;
	unsigned char ipmi_version_minor;

	/* Used for wake ups at startup. */
	wait_queue_head_t waitq;

	struct bmc_device *bmc;
	char *my_dev_name;
	char *sysfs_name;

	/* This is the lower-layer's sender routine.  Note that you
	 * must either be holding the ipmi_interfaces_mutex or be in
	 * an umpreemptible region to use this.  You must fetch the
	 * value into a local variable and make sure it is not NULL. */
	struct ipmi_smi_handlers *handlers;
	void                     *send_info;

#ifdef CONFIG_PROC_FS
	/* A list of proc entries for this interface. */
	struct mutex           proc_entry_lock;
	struct ipmi_proc_entry *proc_entries;
#endif

	/* Driver-model device for the system interface. */
	struct device          *si_dev;

	/* A table of sequence numbers for this interface.  We use the
           sequence numbers for IPMB messages that go out of the
           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 seq_table seq_table[IPMI_IPMB_NUM_SEQ];
	int curr_seq;

	/* Messages that were delayed for some reason (out of memory,
           for instance), will go in here to be processed later in a
           periodic timer interrupt. */
	spinlock_t       waiting_msgs_lock;
	struct list_head waiting_msgs;

	/* The list of command receivers that are registered for commands
	   on this interface. */
	struct mutex     cmd_rcvrs_mutex;
	struct list_head cmd_rcvrs;

	/* Events that were queues because no one was there to receive
           them. */
	spinlock_t       events_lock; /* For dealing with event stuff. */
	struct list_head waiting_events;
	unsigned int     waiting_events_count; /* How many events in queue? */
	int              delivering_events;

	/* The event receiver for my BMC, only really used at panic
	   shutdown as a place to store this. */
	unsigned char event_receiver;
	unsigned char event_receiver_lun;
	unsigned char local_sel_device;
	unsigned char local_event_generator;

	/* For handling of maintenance mode. */
	int maintenance_mode;
	int maintenance_mode_enable;
	int auto_maintenance_timeout;
	spinlock_t maintenance_mode_lock; /* Used in a timer... */

	/* A cheap hack, if this is non-null and a message to an
	   interface comes in with a NULL user, call this routine with
	   it.  Note that the message will still be freed by the
	   caller.  This only works on the system interface. */
	void (*null_user_handler)(ipmi_smi_t intf, struct ipmi_recv_msg *msg);

	/* When we are scanning the channels for an SMI, this will
	   tell which channel we are scanning. */
	int curr_channel;

	/* Channel information */
	struct ipmi_channel channels[IPMI_MAX_CHANNELS];

	/* Proc FS stuff. */
	struct proc_dir_entry *proc_dir;
	char                  proc_dir_name[10];

	spinlock_t   counter_lock; /* For making counters atomic. */

	/* Commands we got that were invalid. */
	unsigned int sent_invalid_commands;

	/* Commands we sent to the MC. */
	unsigned int sent_local_commands;
	/* Responses from the MC that were delivered to a user. */
	unsigned int handled_local_responses;
	/* Responses from the MC that were not delivered to a user. */
	unsigned int unhandled_local_responses;

	/* Commands we sent out to the IPMB bus. */
	unsigned int sent_ipmb_commands;
	/* Commands sent on the IPMB that had errors on the SEND CMD */
	unsigned int sent_ipmb_command_errs;
	/* Each retransmit increments this count. */
	unsigned int retransmitted_ipmb_commands;
	/* When a message times out (runs out of retransmits) this is
           incremented. */
	unsigned int timed_out_ipmb_commands;

	/* This is like above, but for broadcasts.  Broadcasts are
           *not* included in the above count (they are expected to
           time out). */
	unsigned int timed_out_ipmb_broadcasts;

	/* Responses I have sent to the IPMB bus. */
	unsigned int sent_ipmb_responses;

	/* The response was delivered to the user. */
	unsigned int handled_ipmb_responses;
	/* The response had invalid data in it. */
	unsigned int invalid_ipmb_responses;
	/* The response didn't have anyone waiting for it. */
	unsigned int unhandled_ipmb_responses;

	/* Commands we sent out to the IPMB bus. */
	unsigned int sent_lan_commands;
	/* Commands sent on the IPMB that had errors on the SEND CMD */
	unsigned int sent_lan_command_errs;
	/* Each retransmit increments this count. */
	unsigned int retransmitted_lan_commands;
	/* When a message times out (runs out of retransmits) this is
           incremented. */
	unsigned int timed_out_lan_commands;

	/* Responses I have sent to the IPMB bus. */
	unsigned int sent_lan_responses;

	/* The response was delivered to the user. */
	unsigned int handled_lan_responses;
	/* The response had invalid data in it. */
	unsigned int invalid_lan_responses;
	/* The response didn't have anyone waiting for it. */
	unsigned int unhandled_lan_responses;

	/* The command was delivered to the user. */
	unsigned int handled_commands;
	/* The command had invalid data in it. */
	unsigned int invalid_commands;
	/* The command didn't have anyone waiting for it. */
	unsigned int unhandled_commands;

	/* Invalid data in an event. */
	unsigned int invalid_events;
	/* Events that were received with the proper format. */
	unsigned int events;
};
#define to_si_intf_from_dev(device) container_of(device, struct ipmi_smi, dev)

/**
 * The driver model view of the IPMI messaging driver.
 */
static struct device_driver ipmidriver = {
	.name = "ipmi",
	.bus = &platform_bus_type
};
static DEFINE_MUTEX(ipmidriver_mutex);

static struct list_head ipmi_interfaces = LIST_HEAD_INIT(ipmi_interfaces);
static DEFINE_MUTEX(ipmi_interfaces_mutex);

/* List of watchers that want to know when smi's are added and
   deleted. */
static struct list_head smi_watchers = LIST_HEAD_INIT(smi_watchers);
static DEFINE_MUTEX(smi_watchers_mutex);


static void free_recv_msg_list(struct list_head *q)
{
	struct ipmi_recv_msg *msg, *msg2;

	list_for_each_entry_safe(msg, msg2, q, link) {
		list_del(&msg->link);
		ipmi_free_recv_msg(msg);
	}
}

static void free_smi_msg_list(struct list_head *q)
{
	struct ipmi_smi_msg *msg, *msg2;

	list_for_each_entry_safe(msg, msg2, q, link) {
		list_del(&msg->link);
		ipmi_free_smi_msg(msg);
	}
}

static void clean_up_interface_data(ipmi_smi_t intf)
{
	int              i;
	struct cmd_rcvr  *rcvr, *rcvr2;
	struct list_head list;

	free_smi_msg_list(&intf->waiting_msgs);
	free_recv_msg_list(&intf->waiting_events);

	/*
	 * Wholesale remove all the entries from the list in the
	 * interface and wait for RCU to know that none are in use.
	 */
	mutex_lock(&intf->cmd_rcvrs_mutex);
	INIT_LIST_HEAD(&list);
	list_splice_init_rcu(&intf->cmd_rcvrs, &list, synchronize_rcu);
	mutex_unlock(&intf->cmd_rcvrs_mutex);

	list_for_each_entry_safe(rcvr, rcvr2, &list, link)
		kfree(rcvr);

	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
		if ((intf->seq_table[i].inuse)
		    && (intf->seq_table[i].recv_msg))
		{
			ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
		}
	}
}

static void intf_free(struct kref *ref)
{
	ipmi_smi_t intf = container_of(ref, struct ipmi_smi, refcount);

	clean_up_interface_data(intf);
	kfree(intf);
}

struct watcher_entry {
	int              intf_num;
	ipmi_smi_t       intf;
	struct list_head link;
};

int ipmi_smi_watcher_register(struct ipmi_smi_watcher *watcher)
{
	ipmi_smi_t intf;
	struct list_head to_deliver = LIST_HEAD_INIT(to_deliver);
	struct watcher_entry *e, *e2;

	mutex_lock(&smi_watchers_mutex);

	mutex_lock(&ipmi_interfaces_mutex);

	/* Build a list of things to deliver. */
	list_for_each_entry(intf, &ipmi_interfaces, link) {
		if (intf->intf_num == -1)
			continue;
		e = kmalloc(sizeof(*e), GFP_KERNEL);
		if (!e)
			goto out_err;
		kref_get(&intf->refcount);
		e->intf = intf;
		e->intf_num = intf->intf_num;
		list_add_tail(&e->link, &to_deliver);
	}

	/* We will succeed, so add it to the list. */
	list_add(&watcher->link, &smi_watchers);

	mutex_unlock(&ipmi_interfaces_mutex);

	list_for_each_entry_safe(e, e2, &to_deliver, link) {
		list_del(&e->link);
		watcher->new_smi(e->intf_num, e->intf->si_dev);
		kref_put(&e->intf->refcount, intf_free);
		kfree(e);
	}

	mutex_unlock(&smi_watchers_mutex);

	return 0;

 out_err:
	mutex_unlock(&ipmi_interfaces_mutex);
	mutex_unlock(&smi_watchers_mutex);