bte.c

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/*
 * 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) 2000-2007 Silicon Graphics, Inc.  All Rights Reserved.
 */

#include <linux/module.h>
#include <asm/sn/nodepda.h>
#include <asm/sn/addrs.h>
#include <asm/sn/arch.h>
#include <asm/sn/sn_cpuid.h>
#include <asm/sn/pda.h>
#include <asm/sn/shubio.h>
#include <asm/nodedata.h>
#include <asm/delay.h>

#include <linux/bootmem.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include <asm/sn/bte.h>

#ifndef L1_CACHE_MASK
#define L1_CACHE_MASK (L1_CACHE_BYTES - 1)
#endif

/* two interfaces on two btes */
#define MAX_INTERFACES_TO_TRY       4
#define MAX_NODES_TO_TRY        2

static struct bteinfo_s *bte_if_on_node(nasid_t nasid, int interface)
{
    nodepda_t *tmp_nodepda;

    if (nasid_to_cnodeid(nasid) == -1)
        return (struct bteinfo_s *)NULL;

    tmp_nodepda = NODEPDA(nasid_to_cnodeid(nasid));
    return &tmp_nodepda->bte_if[interface];

}

static inline void bte_start_transfer(struct bteinfo_s *bte, u64 len, u64 mode)
{
    if (is_shub2()) {
        BTE_CTRL_STORE(bte, (IBLS_BUSY | ((len) | (mode) << 24)));
    } else {
        BTE_LNSTAT_STORE(bte, len);
        BTE_CTRL_STORE(bte, mode);
    }
}

/************************************************************************
 * Block Transfer Engine copy related functions.
 *
 ***********************************************************************/

/*
 * bte_copy(src, dest, len, mode, notification)
 *
 * Use the block transfer engine to move kernel memory from src to dest
 * using the assigned mode.
 *
 * Parameters:
 *   src - physical address of the transfer source.
 *   dest - physical address of the transfer destination.
 *   len - number of bytes to transfer from source to dest.
 *   mode - hardware defined.  See reference information
 *          for IBCT0/1 in the SHUB Programmers Reference
 *   notification - kernel virtual address of the notification cache
 *                  line.  If NULL, the default is used and
 *                  the bte_copy is synchronous.
 *
 * NOTE:  This function requires src, dest, and len to
 * be cacheline aligned.
 */
bte_result_t bte_copy(u64 src, u64 dest, u64 len, u64 mode, void *notification)
{
    u64 transfer_size;
    u64 transfer_stat;
    u64 notif_phys_addr;
    struct bteinfo_s *bte;
    bte_result_t bte_status;
    unsigned long irq_flags;
    unsigned long itc_end = 0;
    int nasid_to_try[MAX_NODES_TO_TRY];
    int my_nasid = cpuid_to_nasid(raw_smp_processor_id());
    int bte_if_index, nasid_index;
    int bte_first, btes_per_node = BTES_PER_NODE;

    BTE_PRINTK(("bte_copy(0x%lx, 0x%lx, 0x%lx, 0x%lx, 0x%p)\n",
            src, dest, len, mode, notification));

    if (len == 0) {
        return BTE_SUCCESS;
    }

    BUG_ON(len & L1_CACHE_MASK);
    BUG_ON(src & L1_CACHE_MASK);
    BUG_ON(dest & L1_CACHE_MASK);
    BUG_ON(len > BTE_MAX_XFER);

    /*
     * Start with interface corresponding to cpu number
     */
    bte_first = raw_smp_processor_id() % btes_per_node;

    if (mode & BTE_USE_DEST) {
        /* try remote then local */
        nasid_to_try[0] = NASID_GET(dest);
        if (mode & BTE_USE_ANY) {
            nasid_to_try[1] = my_nasid;
        } else {
            nasid_to_try[1] = (int)NULL;
        }
    } else {
        /* try local then remote */
        nasid_to_try[0] = my_nasid;
        if (mode & BTE_USE_ANY) {
            nasid_to_try[1] = NASID_GET(dest);
        } else {
            nasid_to_try[1] = (int)NULL;
        }
    }

retry_bteop:
    do {
        local_irq_save(irq_flags);

        bte_if_index = bte_first;
        nasid_index = 0;

        /* Attempt to lock one of the BTE interfaces. */
        while (nasid_index < MAX_NODES_TO_TRY) {
            bte = bte_if_on_node(nasid_to_try[nasid_index],bte_if_index);

            if (bte == NULL) {
                nasid_index++;
                continue;
            }

            if (spin_trylock(&bte->spinlock)) {
                if (!(*bte->most_rcnt_na & BTE_WORD_AVAILABLE) ||
                    (BTE_LNSTAT_LOAD(bte) & BTE_ACTIVE)) {
                    /* Got the lock but BTE still busy */
                    spin_unlock(&bte->spinlock);
                } else {
                    /* we got the lock and it's not busy */
                    break;
                }
            }

            bte_if_index = (bte_if_index + 1) % btes_per_node; /* Next interface */
            if (bte_if_index == bte_first) {
                /*
                 * We've tried all interfaces on this node
                 */
                nasid_index++;
            }

            bte = NULL;
        }

        if (bte != NULL) {
            break;
        }

        local_irq_restore(irq_flags);

        if (!(mode & BTE_WACQUIRE)) {
            return BTEFAIL_NOTAVAIL;
        }
    } while (1);

    if (notification == NULL) {
        /* User does not want to be notified. */
        bte->most_rcnt_na = &bte->notify;
    } else {
        bte->most_rcnt_na = notification;
    }

    /* Calculate the number of cache lines to transfer. */
    transfer_size = ((len >> L1_CACHE_SHIFT) & BTE_LEN_MASK);

    /* Initialize the notification to a known value. */
    *bte->most_rcnt_na = BTE_WORD_BUSY;
    notif_phys_addr = (u64)bte->most_rcnt_na;

    /* Set the source and destination registers */
    BTE_PRINTKV(("IBSA = 0x%lx)\n", src));
    BTE_SRC_STORE(bte, src);
    BTE_PRINTKV(("IBDA = 0x%lx)\n", dest));
    BTE_DEST_STORE(bte, dest);

    /* Set the notification register */
    BTE_PRINTKV(("IBNA = 0x%lx)\n", notif_phys_addr));
    BTE_NOTIF_STORE(bte, notif_phys_addr);

    /* Initiate the transfer */
    BTE_PRINTK(("IBCT = 0x%lx)\n", BTE_VALID_MODE(mode)));
    bte_start_transfer(bte, transfer_size, BTE_VALID_MODE(mode));

    itc_end = ia64_get_itc() + (40000000 * local_cpu_data->cyc_per_usec);

    spin_unlock_irqrestore(&bte->spinlock, irq_flags);

    if (notification != NULL) {
        return BTE_SUCCESS;
    }

    while ((transfer_stat = *bte->most_rcnt_na) == BTE_WORD_BUSY) {
        cpu_relax();
        if (ia64_get_itc() > itc_end) {
            BTE_PRINTK(("BTE timeout nasid 0x%x bte%d IBLS = 0x%lx na 0x%lx\n",
                NASID_GET(bte->bte_base_addr), bte->bte_num,
                BTE_LNSTAT_LOAD(bte), *bte->most_rcnt_na) );
            bte->bte_error_count++;
            bte->bh_error = IBLS_ERROR;
            bte_error_handler((unsigned long)NODEPDA(bte->bte_cnode));
            *bte->most_rcnt_na = BTE_WORD_AVAILABLE;
            goto retry_bteop;
        }
    }

    BTE_PRINTKV((" Delay Done.  IBLS = 0x%lx, most_rcnt_na = 0x%lx\n",
             BTE_LNSTAT_LOAD(bte), *bte->most_rcnt_na));

    if (transfer_stat & IBLS_ERROR) {
        bte_status = BTE_GET_ERROR_STATUS(transfer_stat);
    } else {
        bte_status = BTE_SUCCESS;
    }
    *bte->most_rcnt_na = BTE_WORD_AVAILABLE;

    BTE_PRINTK(("Returning status is 0x%lx and most_rcnt_na is 0x%lx\n",
            BTE_LNSTAT_LOAD(bte), *bte->most_rcnt_na));

    return bte_status;
}

EXPORT_SYMBOL(bte_copy);

/*
 * bte_unaligned_copy(src, dest, len, mode)
 *
 * use the block transfer engine to move kernel
 * memory from src to dest using the assigned mode.
 *
 * Parameters:
 *   src - physical address of the transfer source.
 *   dest - physical address of the transfer destination.
 *   len - number of bytes to transfer from source to dest.
 *   mode - hardware defined.  See reference information
 *          for IBCT0/1 in the SGI documentation.
 *
 * NOTE: If the source, dest, and len are all cache line aligned,
 * then it would be _FAR_ preferable to use bte_copy instead.
 */
bte_result_t bte_unaligned_copy(u64 src, u64 dest, u64 len, u64 mode)
{
    int destFirstCacheOffset;
    u64 headBteSource;
    u64 headBteLen;
    u64 headBcopySrcOffset;
    u64 headBcopyDest;
    u64 headBcopyLen;
    u64 footBteSource;
    u64 footBteLen;
    u64 footBcopyDest;
    u64 footBcopyLen;
    bte_result_t rv;
    char *bteBlock, *bteBlock_unaligned;

    if (len == 0) {
        return BTE_SUCCESS;
    }

    /* temporary buffer used during unaligned transfers */
    bteBlock_unaligned = kmalloc(len + 3 * L1_CACHE_BYTES, GFP_KERNEL);
    if (bteBlock_unaligned == NULL) {
        return BTEFAIL_NOTAVAIL;
    }
    bteBlock = (char *)L1_CACHE_ALIGN((u64) bteBlock_unaligned);

    headBcopySrcOffset = src & L1_CACHE_MASK;
    destFirstCacheOffset = dest & L1_CACHE_MASK;

    /*
     * At this point, the transfer is broken into
     * (up to) three sections.  The first section is
     * from the start address to the first physical
     * cache line, the second is from the first physical
     * cache line to the last complete cache line,
     * and the third is from the last cache line to the
     * end of the buffer.  The first and third sections
     * are handled by bte copying into a temporary buffer
     * and then bcopy'ing the necessary section into the
     * final location.  The middle section is handled with
     * a standard bte copy.
     *
     * One nasty exception to the above rule is when the
     * source and destination are not symmetrically
     * mis-aligned.  If the source offset from the first
     * cache line is different from the destination offset,
     * we make the first section be the entire transfer
     * and the bcopy the entire block into place.
     */
    if (headBcopySrcOffset == destFirstCacheOffset) {

        /*
         * Both the source and destination are the same
         * distance from a cache line boundary so we can
         * use the bte to transfer the bulk of the
         * data.
         */
        headBteSource = src & ~L1_CACHE_MASK;
        headBcopyDest = dest;
        if (headBcopySrcOffset) {
            headBcopyLen =
                (len >
                 (L1_CACHE_BYTES -
                  headBcopySrcOffset) ? L1_CACHE_BYTES
                 - headBcopySrcOffset : len);
            headBteLen = L1_CACHE_BYTES;
        } else {
            headBcopyLen = 0;
            headBteLen = 0;
        }

        if (len > headBcopyLen) {
            footBcopyLen = (len - headBcopyLen) & L1_CACHE_MASK;
            footBteLen = L1_CACHE_BYTES;

            footBteSource = src + len - footBcopyLen;
            footBcopyDest = dest + len - footBcopyLen;

            if (footBcopyDest == (headBcopyDest + headBcopyLen)) {
                /*
                 * We have two contiguous bcopy
                 * blocks.  Merge them.
                 */
                headBcopyLen += footBcopyLen;
                headBteLen += footBteLen;
            } else if (footBcopyLen > 0) {
                rv = bte_copy(footBteSource,
                          ia64_tpa((unsigned long)bteBlock),
                          footBteLen, mode, NULL);
                if (rv != BTE_SUCCESS) {
                    kfree(bteBlock_unaligned);
                    return rv;
                }

                memcpy(__va(footBcopyDest),
                       (char *)bteBlock, footBcopyLen);
            }
        } else {
            footBcopyLen = 0;
            footBteLen = 0;
        }

        if (len > (headBcopyLen + footBcopyLen)) {
            /* now transfer the middle. */
            rv = bte_copy((src + headBcopyLen),
                      (dest +
                       headBcopyLen),
                      (len - headBcopyLen -
                       footBcopyLen), mode, NULL);
            if (rv != BTE_SUCCESS) {
                kfree(bteBlock_unaligned);
                return rv;
            }

        }
    } else {

        /*
         * The transfer is not symmetric, we will
         * allocate a buffer large enough for all the
         * data, bte_copy into that buffer and then
         * bcopy to the destination.
         */

        headBcopySrcOffset = src & L1_CACHE_MASK;
        headBcopyDest = dest;
        headBcopyLen = len;

        headBteSource = src - headBcopySrcOffset;
        /* Add the leading and trailing bytes from source */
        headBteLen = L1_CACHE_ALIGN(len + headBcopySrcOffset);
    }

    if (headBcopyLen > 0) {
        rv = bte_copy(headBteSource,
                  ia64_tpa((unsigned long)bteBlock), headBteLen,
                  mode, NULL);
        if (rv != BTE_SUCCESS) {
            kfree(bteBlock_unaligned);
            return rv;
        }

        memcpy(__va(headBcopyDest), ((char *)bteBlock +
                         headBcopySrcOffset), headBcopyLen);
    }
    kfree(bteBlock_unaligned);
    return BTE_SUCCESS;
}

EXPORT_SYMBOL(bte_unaligned_copy);

/************************************************************************
 * Block Transfer Engine initialization functions.
 *
 ***********************************************************************/

/*
 * bte_init_node(nodepda, cnode)
 *
 * Initialize the nodepda structure with BTE base addresses and
 * spinlocks.
 */
void bte_init_node(nodepda_t * mynodepda, cnodeid_t cnode)
{
    int i;

    /*
     * Indicate that all the block transfer engines on this node
     * are available.
     */

    /*
     * Allocate one bte_recover_t structure per node.  It holds
     * the recovery lock for node.  All the bte interface structures
     * will point at this one bte_recover structure to get the lock.
     */
    spin_lock_init(&mynodepda->bte_recovery_lock);
    init_timer(&mynodepda->bte_recovery_timer);
    mynodepda->bte_recovery_timer.function = bte_error_handler;
    mynodepda->bte_recovery_timer.data = (unsigned long)mynodepda;

    for (i = 0; i < BTES_PER_NODE; i++) {
        u64 *base_addr;

        /* Which link status register should we use? */
        base_addr = (u64 *)
            REMOTE_HUB_ADDR(cnodeid_to_nasid(cnode), BTE_BASE_ADDR(i));
        mynodepda->bte_if[i].bte_base_addr = base_addr;
        mynodepda->bte_if[i].bte_source_addr = BTE_SOURCE_ADDR(base_addr);
        mynodepda->bte_if[i].bte_destination_addr = BTE_DEST_ADDR(base_addr);
        mynodepda->bte_if[i].bte_control_addr = BTE_CTRL_ADDR(base_addr);
        mynodepda->bte_if[i].bte_notify_addr = BTE_NOTIF_ADDR(base_addr);

        /*
         * Initialize the notification and spinlock
         * so the first transfer can occur.
         */
        mynodepda->bte_if[i].most_rcnt_na =
            &(mynodepda->bte_if[i].notify);
        mynodepda->bte_if[i].notify = BTE_WORD_AVAILABLE;
        spin_lock_init(&mynodepda->bte_if[i].spinlock);

        mynodepda->bte_if[i].bte_cnode = cnode;
        mynodepda->bte_if[i].bte_error_count = 0;
        mynodepda->bte_if[i].bte_num = i;
        mynodepda->bte_if[i].cleanup_active = 0;
        mynodepda->bte_if[i].bh_error = 0;
    }

}