sgi-xp: isolate xpc_vars_part structure to sn2 only

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / misc / sgi-xp / xpc_sn2.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
 */

/*
 * Cross Partition Communication (XPC) sn2-based functions.
 *
 *     Architecture specific implementation of common functions.
 *
 */

#include <linux/kernel.h>
#include <linux/delay.h>
#include <asm/uncached.h>
#include <asm/sn/sn_sal.h>
#include "xpc.h"

struct xpc_vars *xpc_vars;
static struct xpc_vars_part_sn2 *xpc_vars_part; /* >>> Add _sn2 suffix? */

static enum xp_retval
xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
{
        AMO_t *amos_page;
        u64 nasid_array = 0;
        int i;
        int ret;

        xpc_vars = XPC_RP_VARS(rp);

        rp->sn.vars_pa = __pa(xpc_vars);

        /* vars_part array follows immediately after vars */
        xpc_vars_part = (struct xpc_vars_part_sn2 *)((u8 *)XPC_RP_VARS(rp) +
                                                     XPC_RP_VARS_SIZE);


        /*
         * Before clearing xpc_vars, see if a page of AMOs had been previously
         * allocated. If not we'll need to allocate one and set permissions
         * so that cross-partition AMOs are allowed.
         *
         * The allocated AMO page needs MCA reporting to remain disabled after
         * XPC has unloaded.  To make this work, we keep a copy of the pointer
         * to this page (i.e., amos_page) in the struct xpc_vars structure,
         * which is pointed to by the reserved page, and re-use that saved copy
         * on subsequent loads of XPC. This AMO page is never freed, and its
         * memory protections are never restricted.
         */
        amos_page = xpc_vars->amos_page;
        if (amos_page == NULL) {
                amos_page = (AMO_t *)TO_AMO(uncached_alloc_page(0, 1));
                if (amos_page == NULL) {
                        dev_err(xpc_part, "can't allocate page of AMOs\n");
                        return xpNoMemory;
                }

                /*
                 * Open up AMO-R/W to cpu.  This is done for Shub 1.1 systems
                 * when xpc_allow_IPI_ops() is called via xpc_hb_init().
                 */
                if (!enable_shub_wars_1_1()) {
                        ret = sn_change_memprotect(ia64_tpa((u64)amos_page),
                                                   PAGE_SIZE,
                                                   SN_MEMPROT_ACCESS_CLASS_1,
                                                   &nasid_array);
                        if (ret != 0) {
                                dev_err(xpc_part, "can't change memory "
                                        "protections\n");
                                uncached_free_page(__IA64_UNCACHED_OFFSET |
                                                   TO_PHYS((u64)amos_page), 1);
                                return xpSalError;
                        }
                }
        }

        /* clear xpc_vars */
        memset(xpc_vars, 0, sizeof(struct xpc_vars));

        xpc_vars->version = XPC_V_VERSION;
        xpc_vars->act_nasid = cpuid_to_nasid(0);
        xpc_vars->act_phys_cpuid = cpu_physical_id(0);
        xpc_vars->vars_part_pa = __pa(xpc_vars_part);
        xpc_vars->amos_page_pa = ia64_tpa((u64)amos_page);
        xpc_vars->amos_page = amos_page;        /* save for next load of XPC */

        /* clear xpc_vars_part */
        memset((u64 *)xpc_vars_part, 0, sizeof(struct xpc_vars_part_sn2) *
               xp_max_npartitions);

        /* initialize the activate IRQ related AMO variables */
        for (i = 0; i < xp_nasid_mask_words; i++)
                (void)xpc_IPI_init(XPC_ACTIVATE_IRQ_AMOS + i);

        /* initialize the engaged remote partitions related AMO variables */
        (void)xpc_IPI_init(XPC_ENGAGED_PARTITIONS_AMO);
        (void)xpc_IPI_init(XPC_DISENGAGE_REQUEST_AMO);

        return xpSuccess;
}

/*
 * Setup the infrastructure necessary to support XPartition Communication
 * between the specified remote partition and the local one.
 */
static enum xp_retval
xpc_setup_infrastructure_sn2(struct xpc_partition *part)
{
        enum xp_retval retval;
        int ret;
        int cpuid;
        int ch_number;
        struct xpc_channel *ch;
        struct timer_list *timer;
        short partid = XPC_PARTID(part);

        /*
         * Allocate all of the channel structures as a contiguous chunk of
         * memory.
         */
        DBUG_ON(part->channels != NULL);
        part->channels = kzalloc(sizeof(struct xpc_channel) * XPC_MAX_NCHANNELS,
                                 GFP_KERNEL);
        if (part->channels == NULL) {
                dev_err(xpc_chan, "can't get memory for channels\n");
                return xpNoMemory;
        }

        /* allocate all the required GET/PUT values */

        part->local_GPs = xpc_kzalloc_cacheline_aligned(XPC_GP_SIZE,
                                                        GFP_KERNEL,
                                                        &part->local_GPs_base);
        if (part->local_GPs == NULL) {
                dev_err(xpc_chan, "can't get memory for local get/put "
                        "values\n");
                retval = xpNoMemory;
                goto out_1;
        }

        part->remote_GPs = xpc_kzalloc_cacheline_aligned(XPC_GP_SIZE,
                                                         GFP_KERNEL,
                                                         &part->
                                                         remote_GPs_base);
        if (part->remote_GPs == NULL) {
                dev_err(xpc_chan, "can't get memory for remote get/put "
                        "values\n");
                retval = xpNoMemory;
                goto out_2;
        }

        part->remote_GPs_pa = 0;

        /* allocate all the required open and close args */

        part->local_openclose_args =
            xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
                                          &part->local_openclose_args_base);
        if (part->local_openclose_args == NULL) {
                dev_err(xpc_chan, "can't get memory for local connect args\n");
                retval = xpNoMemory;
                goto out_3;
        }

        part->remote_openclose_args =
            xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
                                          &part->remote_openclose_args_base);
        if (part->remote_openclose_args == NULL) {
                dev_err(xpc_chan, "can't get memory for remote connect args\n");
                retval = xpNoMemory;
                goto out_4;
        }

        part->remote_openclose_args_pa = 0;

        part->local_IPI_amo_va = xpc_IPI_init(partid);
        part->local_IPI_amo = 0;
        spin_lock_init(&part->IPI_lock);

        part->remote_IPI_nasid = 0;
        part->remote_IPI_phys_cpuid = 0;
        part->remote_IPI_amo_va = NULL;

        atomic_set(&part->channel_mgr_requests, 1);
        init_waitqueue_head(&part->channel_mgr_wq);

        sprintf(part->IPI_owner, "xpc%02d", partid);
        ret = request_irq(SGI_XPC_NOTIFY, xpc_notify_IRQ_handler, IRQF_SHARED,
                          part->IPI_owner, (void *)(u64)partid);
        if (ret != 0) {
                dev_err(xpc_chan, "can't register NOTIFY IRQ handler, "
                        "errno=%d\n", -ret);
                retval = xpLackOfResources;
                goto out_5;
        }

        /* Setup a timer to check for dropped IPIs */
        timer = &part->dropped_IPI_timer;
        init_timer(timer);
        timer->function = (void (*)(unsigned long))xpc_dropped_IPI_check;
        timer->data = (unsigned long)part;
        timer->expires = jiffies + XPC_P_DROPPED_IPI_WAIT_INTERVAL;
        add_timer(timer);

        part->nchannels = XPC_MAX_NCHANNELS;

        atomic_set(&part->nchannels_active, 0);
        atomic_set(&part->nchannels_engaged, 0);

        for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
                ch = &part->channels[ch_number];

                ch->partid = partid;
                ch->number = ch_number;
                ch->flags = XPC_C_DISCONNECTED;

                ch->local_GP = &part->local_GPs[ch_number];
                ch->local_openclose_args =
                    &part->local_openclose_args[ch_number];

                atomic_set(&ch->kthreads_assigned, 0);
                atomic_set(&ch->kthreads_idle, 0);
                atomic_set(&ch->kthreads_active, 0);

                atomic_set(&ch->references, 0);
                atomic_set(&ch->n_to_notify, 0);

                spin_lock_init(&ch->lock);
                mutex_init(&ch->msg_to_pull_mutex);
                init_completion(&ch->wdisconnect_wait);

                atomic_set(&ch->n_on_msg_allocate_wq, 0);
                init_waitqueue_head(&ch->msg_allocate_wq);
                init_waitqueue_head(&ch->idle_wq);
        }

        /*
         * With the setting of the partition setup_state to XPC_P_SETUP, we're
         * declaring that this partition is ready to go.
         */
        part->setup_state = XPC_P_SETUP;

        /*
         * Setup the per partition specific variables required by the
         * remote partition to establish channel connections with us.
         *
         * The setting of the magic # indicates that these per partition
         * specific variables are ready to be used.
         */
        xpc_vars_part[partid].GPs_pa = __pa(part->local_GPs);
        xpc_vars_part[partid].openclose_args_pa =
            __pa(part->local_openclose_args);
        xpc_vars_part[partid].IPI_amo_pa = __pa(part->local_IPI_amo_va);
        cpuid = raw_smp_processor_id(); /* any CPU in this partition will do */
        xpc_vars_part[partid].IPI_nasid = cpuid_to_nasid(cpuid);
        xpc_vars_part[partid].IPI_phys_cpuid = cpu_physical_id(cpuid);
        xpc_vars_part[partid].nchannels = part->nchannels;
        xpc_vars_part[partid].magic = XPC_VP_MAGIC1;

        return xpSuccess;

        /* setup of infrastructure failed */
out_5:
        kfree(part->remote_openclose_args_base);
        part->remote_openclose_args = NULL;
out_4:
        kfree(part->local_openclose_args_base);
        part->local_openclose_args = NULL;
out_3:
        kfree(part->remote_GPs_base);
        part->remote_GPs = NULL;
out_2:
        kfree(part->local_GPs_base);
        part->local_GPs = NULL;
out_1:
        kfree(part->channels);
        part->channels = NULL;
        return retval;
}

/*
 * Teardown the infrastructure necessary to support XPartition Communication
 * between the specified remote partition and the local one.
 */
static void
xpc_teardown_infrastructure_sn2(struct xpc_partition *part)
{
        short partid = XPC_PARTID(part);

        /*
         * We start off by making this partition inaccessible to local
         * processes by marking it as no longer setup. Then we make it
         * inaccessible to remote processes by clearing the XPC per partition
         * specific variable's magic # (which indicates that these variables
         * are no longer valid) and by ignoring all XPC notify IPIs sent to
         * this partition.
         */

        DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
        DBUG_ON(atomic_read(&part->nchannels_active) != 0);
        DBUG_ON(part->setup_state != XPC_P_SETUP);
        part->setup_state = XPC_P_WTEARDOWN;

        xpc_vars_part[partid].magic = 0;

        free_irq(SGI_XPC_NOTIFY, (void *)(u64)partid);

        /*
         * Before proceeding with the teardown we have to wait until all
         * existing references cease.
         */
        wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));

        /* now we can begin tearing down the infrastructure */

        part->setup_state = XPC_P_TORNDOWN;

        /* in case we've still got outstanding timers registered... */
        del_timer_sync(&part->dropped_IPI_timer);

        kfree(part->remote_openclose_args_base);
        part->remote_openclose_args = NULL;
        kfree(part->local_openclose_args_base);
        part->local_openclose_args = NULL;
        kfree(part->remote_GPs_base);
        part->remote_GPs = NULL;
        kfree(part->local_GPs_base);
        part->local_GPs = NULL;
        kfree(part->channels);
        part->channels = NULL;
        part->local_IPI_amo_va = NULL;
}

/*
 * Create a wrapper that hides the underlying mechanism for pulling a cacheline
 * (or multiple cachelines) from a remote partition.
 *
 * src must be a cacheline aligned physical address on the remote partition.
 * dst must be a cacheline aligned virtual address on this partition.
 * cnt must be cacheline sized
 */
/* >>> Replace this function by call to xp_remote_memcpy() or bte_copy()? */
static enum xp_retval
xpc_pull_remote_cachelines_sn2(struct xpc_partition *part, void *dst,
                               const void *src, size_t cnt)
{
        enum xp_retval ret;

        DBUG_ON((u64)src != L1_CACHE_ALIGN((u64)src));
        DBUG_ON((u64)dst != L1_CACHE_ALIGN((u64)dst));
        DBUG_ON(cnt != L1_CACHE_ALIGN(cnt));

        if (part->act_state == XPC_P_DEACTIVATING)
                return part->reason;

        ret = xp_remote_memcpy(dst, src, cnt);
        if (ret != xpSuccess) {
                dev_dbg(xpc_chan, "xp_remote_memcpy() from partition %d failed,"
                        " ret=%d\n", XPC_PARTID(part), ret);
        }
        return ret;
}

/*
 * Pull the remote per partition specific variables from the specified
 * partition.
 */
static enum xp_retval
xpc_pull_remote_vars_part_sn2(struct xpc_partition *part)
{
        u8 buffer[L1_CACHE_BYTES * 2];
        struct xpc_vars_part_sn2 *pulled_entry_cacheline =
            (struct xpc_vars_part_sn2 *)L1_CACHE_ALIGN((u64)buffer);
        struct xpc_vars_part_sn2 *pulled_entry;
        u64 remote_entry_cacheline_pa, remote_entry_pa;
        short partid = XPC_PARTID(part);
        enum xp_retval ret;

        /* pull the cacheline that contains the variables we're interested in */

        DBUG_ON(part->remote_vars_part_pa !=
                L1_CACHE_ALIGN(part->remote_vars_part_pa));
        DBUG_ON(sizeof(struct xpc_vars_part_sn2) != L1_CACHE_BYTES / 2);

        remote_entry_pa = part->remote_vars_part_pa +
            sn_partition_id * sizeof(struct xpc_vars_part_sn2);

        remote_entry_cacheline_pa = (remote_entry_pa & ~(L1_CACHE_BYTES - 1));

        pulled_entry = (struct xpc_vars_part_sn2 *)((u64)pulled_entry_cacheline
                                                    + (remote_entry_pa &
                                                    (L1_CACHE_BYTES - 1)));

        ret = xpc_pull_remote_cachelines_sn2(part, pulled_entry_cacheline,
                                             (void *)remote_entry_cacheline_pa,
                                             L1_CACHE_BYTES);
        if (ret != xpSuccess) {
                dev_dbg(xpc_chan, "failed to pull XPC vars_part from "
                        "partition %d, ret=%d\n", partid, ret);
                return ret;
        }

        /* see if they've been set up yet */

        if (pulled_entry->magic != XPC_VP_MAGIC1 &&
            pulled_entry->magic != XPC_VP_MAGIC2) {

                if (pulled_entry->magic != 0) {
                        dev_dbg(xpc_chan, "partition %d's XPC vars_part for "
                                "partition %d has bad magic value (=0x%lx)\n",
                                partid, sn_partition_id, pulled_entry->magic);
                        return xpBadMagic;
                }

                /* they've not been initialized yet */
                return xpRetry;
        }

        if (xpc_vars_part[partid].magic == XPC_VP_MAGIC1) {

                /* validate the variables */

                if (pulled_entry->GPs_pa == 0 ||
                    pulled_entry->openclose_args_pa == 0 ||
                    pulled_entry->IPI_amo_pa == 0) {

                        dev_err(xpc_chan, "partition %d's XPC vars_part for "
                                "partition %d are not valid\n", partid,
                                sn_partition_id);
                        return xpInvalidAddress;
                }

                /* the variables we imported look to be valid */

                part->remote_GPs_pa = pulled_entry->GPs_pa;
                part->remote_openclose_args_pa =
                    pulled_entry->openclose_args_pa;
                part->remote_IPI_amo_va =
                    (AMO_t *)__va(pulled_entry->IPI_amo_pa);
                part->remote_IPI_nasid = pulled_entry->IPI_nasid;
                part->remote_IPI_phys_cpuid = pulled_entry->IPI_phys_cpuid;

                if (part->nchannels > pulled_entry->nchannels)
                        part->nchannels = pulled_entry->nchannels;

                /* let the other side know that we've pulled their variables */

                xpc_vars_part[partid].magic = XPC_VP_MAGIC2;
        }

        if (pulled_entry->magic == XPC_VP_MAGIC1)
                return xpRetry;

        return xpSuccess;
}

/*
 * Establish first contact with the remote partititon. This involves pulling
 * the XPC per partition variables from the remote partition and waiting for
 * the remote partition to pull ours.
 */
static enum xp_retval
xpc_make_first_contact_sn2(struct xpc_partition *part)
{
        enum xp_retval ret;

        while ((ret = xpc_pull_remote_vars_part_sn2(part)) != xpSuccess) {
                if (ret != xpRetry) {
                        XPC_DEACTIVATE_PARTITION(part, ret);
                        return ret;
                }

                dev_dbg(xpc_part, "waiting to make first contact with "
                        "partition %d\n", XPC_PARTID(part));

                /* wait a 1/4 of a second or so */
                (void)msleep_interruptible(250);

                if (part->act_state == XPC_P_DEACTIVATING)
                        return part->reason;
        }

        return xpSuccess;
}

/*
 * Get the IPI flags and pull the openclose args and/or remote GPs as needed.
 */
static u64
xpc_get_IPI_flags_sn2(struct xpc_partition *part)
{
        unsigned long irq_flags;
        u64 IPI_amo;
        enum xp_retval ret;

        /*
         * See if there are any IPI flags to be handled.
         */

        spin_lock_irqsave(&part->IPI_lock, irq_flags);
        IPI_amo = part->local_IPI_amo;
        if (IPI_amo != 0)
                part->local_IPI_amo = 0;

        spin_unlock_irqrestore(&part->IPI_lock, irq_flags);

        if (XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(IPI_amo)) {
                ret = xpc_pull_remote_cachelines_sn2(part,
                                                    part->remote_openclose_args,
                                                     (void *)part->
                                                     remote_openclose_args_pa,
                                                     XPC_OPENCLOSE_ARGS_SIZE);
                if (ret != xpSuccess) {
                        XPC_DEACTIVATE_PARTITION(part, ret);

                        dev_dbg(xpc_chan, "failed to pull openclose args from "
                                "partition %d, ret=%d\n", XPC_PARTID(part),
                                ret);

                        /* don't bother processing IPIs anymore */
                        IPI_amo = 0;
                }
        }

        if (XPC_ANY_MSG_IPI_FLAGS_SET(IPI_amo)) {
                ret = xpc_pull_remote_cachelines_sn2(part, part->remote_GPs,
                                                    (void *)part->remote_GPs_pa,
                                                     XPC_GP_SIZE);
                if (ret != xpSuccess) {
                        XPC_DEACTIVATE_PARTITION(part, ret);

                        dev_dbg(xpc_chan, "failed to pull GPs from partition "
                                "%d, ret=%d\n", XPC_PARTID(part), ret);

                        /* don't bother processing IPIs anymore */
                        IPI_amo = 0;
                }
        }

        return IPI_amo;
}

static struct xpc_msg *
xpc_pull_remote_msg_sn2(struct xpc_channel *ch, s64 get)
{
        struct xpc_partition *part = &xpc_partitions[ch->partid];
        struct xpc_msg *remote_msg, *msg;
        u32 msg_index, nmsgs;
        u64 msg_offset;
        enum xp_retval ret;

        if (mutex_lock_interruptible(&ch->msg_to_pull_mutex) != 0) {
                /* we were interrupted by a signal */
                return NULL;
        }

        while (get >= ch->next_msg_to_pull) {

                /* pull as many messages as are ready and able to be pulled */

                msg_index = ch->next_msg_to_pull % ch->remote_nentries;

                DBUG_ON(ch->next_msg_to_pull >= ch->w_remote_GP.put);
                nmsgs = ch->w_remote_GP.put - ch->next_msg_to_pull;
                if (msg_index + nmsgs > ch->remote_nentries) {
                        /* ignore the ones that wrap the msg queue for now */
                        nmsgs = ch->remote_nentries - msg_index;
                }

                msg_offset = msg_index * ch->msg_size;
                msg = (struct xpc_msg *)((u64)ch->remote_msgqueue + msg_offset);
                remote_msg = (struct xpc_msg *)(ch->remote_msgqueue_pa +
                                                msg_offset);

                ret = xpc_pull_remote_cachelines_sn2(part, msg, remote_msg,
                                                     nmsgs * ch->msg_size);
                if (ret != xpSuccess) {

                        dev_dbg(xpc_chan, "failed to pull %d msgs starting with"
                                " msg %ld from partition %d, channel=%d, "
                                "ret=%d\n", nmsgs, ch->next_msg_to_pull,
                                ch->partid, ch->number, ret);

                        XPC_DEACTIVATE_PARTITION(part, ret);

                        mutex_unlock(&ch->msg_to_pull_mutex);
                        return NULL;
                }

                ch->next_msg_to_pull += nmsgs;
        }

        mutex_unlock(&ch->msg_to_pull_mutex);

        /* return the message we were looking for */
        msg_offset = (get % ch->remote_nentries) * ch->msg_size;
        msg = (struct xpc_msg *)((u64)ch->remote_msgqueue + msg_offset);

        return msg;
}

/*
 * Get a message to be delivered.
 */
static struct xpc_msg *
xpc_get_deliverable_msg_sn2(struct xpc_channel *ch)
{
        struct xpc_msg *msg = NULL;
        s64 get;

        do {
                if (ch->flags & XPC_C_DISCONNECTING)
                        break;

                get = ch->w_local_GP.get;
                rmb();  /* guarantee that .get loads before .put */
                if (get == ch->w_remote_GP.put)
                        break;

                /* There are messages waiting to be pulled and delivered.
                 * We need to try to secure one for ourselves. We'll do this
                 * by trying to increment w_local_GP.get and hope that no one
                 * else beats us to it. If they do, we'll we'll simply have
                 * to try again for the next one.
                 */

                if (cmpxchg(&ch->w_local_GP.get, get, get + 1) == get) {
                        /* we got the entry referenced by get */

                        dev_dbg(xpc_chan, "w_local_GP.get changed to %ld, "
                                "partid=%d, channel=%d\n", get + 1,
                                ch->partid, ch->number);

                        /* pull the message from the remote partition */

                        msg = xpc_pull_remote_msg_sn2(ch, get);

                        DBUG_ON(msg != NULL && msg->number != get);
                        DBUG_ON(msg != NULL && (msg->flags & XPC_M_DONE));
                        DBUG_ON(msg != NULL && !(msg->flags & XPC_M_READY));

                        break;
                }

        } while (1);

        return msg;
}

void
xpc_init_sn2(void)
{
        xpc_rsvd_page_init = xpc_rsvd_page_init_sn2;
        xpc_setup_infrastructure = xpc_setup_infrastructure_sn2;
        xpc_teardown_infrastructure = xpc_teardown_infrastructure_sn2;
        xpc_make_first_contact = xpc_make_first_contact_sn2;
        xpc_get_IPI_flags = xpc_get_IPI_flags_sn2;
        xpc_get_deliverable_msg = xpc_get_deliverable_msg_sn2;
}

void
xpc_exit_sn2(void)
{
}