pcibr_ate.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) 2001-2006 Silicon Graphics, Inc. All rights reserved.
 */

#include <linux/types.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/pcibr_provider.h>
#include <asm/sn/pcibus_provider_defs.h>
#include <asm/sn/pcidev.h>

int pcibr_invalidate_ate;   /* by default don't invalidate ATE on free */

/*
 * mark_ate: Mark the ate as either free or inuse.
 */
static void mark_ate(struct ate_resource *ate_resource, int start, int number,
             u64 value)
{
    u64 *ate = ate_resource->ate;
    int index;
    int length = 0;

    for (index = start; length < number; index++, length++)
        ate[index] = value;
}

/*
 * find_free_ate:  Find the first free ate index starting from the given
 *         index for the desired consecutive count.
 */
static int find_free_ate(struct ate_resource *ate_resource, int start,
             int count)
{
    u64 *ate = ate_resource->ate;
    int index;
    int start_free;

    for (index = start; index < ate_resource->num_ate;) {
        if (!ate[index]) {
            int i;
            int free;
            free = 0;
            start_free = index; /* Found start free ate */
            for (i = start_free; i < ate_resource->num_ate; i++) {
                if (!ate[i]) {  /* This is free */
                    if (++free == count)
                        return start_free;
                } else {
                    index = i + 1;
                    break;
                }
            }
            if (i >= ate_resource->num_ate)
                return -1;
        } else
            index++;    /* Try next ate */
    }

    return -1;
}

/*
 * free_ate_resource:  Free the requested number of ATEs.
 */
static inline void free_ate_resource(struct ate_resource *ate_resource,
                     int start)
{
    mark_ate(ate_resource, start, ate_resource->ate[start], 0);
    if ((ate_resource->lowest_free_index > start) ||
        (ate_resource->lowest_free_index < 0))
        ate_resource->lowest_free_index = start;
}

/*
 * alloc_ate_resource:  Allocate the requested number of ATEs.
 */
static inline int alloc_ate_resource(struct ate_resource *ate_resource,
                     int ate_needed)
{
    int start_index;

    /*
     * Check for ate exhaustion.
     */
    if (ate_resource->lowest_free_index < 0)
        return -1;

    /*
     * Find the required number of free consecutive ates.
     */
    start_index =
        find_free_ate(ate_resource, ate_resource->lowest_free_index,
              ate_needed);
    if (start_index >= 0)
        mark_ate(ate_resource, start_index, ate_needed, ate_needed);

    ate_resource->lowest_free_index =
        find_free_ate(ate_resource, ate_resource->lowest_free_index, 1);

    return start_index;
}

/*
 * Allocate "count" contiguous Bridge Address Translation Entries
 * on the specified bridge to be used for PCI to XTALK mappings.
 * Indices in rm map range from 1..num_entries.  Indices returned
 * to caller range from 0..num_entries-1.
 *
 * Return the start index on success, -1 on failure.
 */
int pcibr_ate_alloc(struct pcibus_info *pcibus_info, int count)
{
    int status;
    unsigned long flags;

    spin_lock_irqsave(&pcibus_info->pbi_lock, flags);
    status = alloc_ate_resource(&pcibus_info->pbi_int_ate_resource, count);
    spin_unlock_irqrestore(&pcibus_info->pbi_lock, flags);

    return status;
}

/*
 * Setup an Address Translation Entry as specified.  Use either the Bridge
 * internal maps or the external map RAM, as appropriate.
 */
static inline u64 __iomem *pcibr_ate_addr(struct pcibus_info *pcibus_info,
                       int ate_index)
{
    if (ate_index < pcibus_info->pbi_int_ate_size) {
        return pcireg_int_ate_addr(pcibus_info, ate_index);
    }
    panic("pcibr_ate_addr: invalid ate_index 0x%x", ate_index);
}

/*
 * Update the ate.
 */
void inline
ate_write(struct pcibus_info *pcibus_info, int ate_index, int count,
      volatile u64 ate)
{
    while (count-- > 0) {
        if (ate_index < pcibus_info->pbi_int_ate_size) {
            pcireg_int_ate_set(pcibus_info, ate_index, ate);
        } else {
            panic("ate_write: invalid ate_index 0x%x", ate_index);
        }
        ate_index++;
        ate += IOPGSIZE;
    }

    pcireg_tflush_get(pcibus_info); /* wait until Bridge PIO complete */
}

void pcibr_ate_free(struct pcibus_info *pcibus_info, int index)
{

    volatile u64 ate;
    int count;
    unsigned long flags;

    if (pcibr_invalidate_ate) {
        /* For debugging purposes, clear the valid bit in the ATE */
        ate = *pcibr_ate_addr(pcibus_info, index);
        count = pcibus_info->pbi_int_ate_resource.ate[index];
        ate_write(pcibus_info, index, count, (ate & ~PCI32_ATE_V));
    }

    spin_lock_irqsave(&pcibus_info->pbi_lock, flags);
    free_ate_resource(&pcibus_info->pbi_int_ate_resource, index);
    spin_unlock_irqrestore(&pcibus_info->pbi_lock, flags);
}