tce_64.c

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/*
 * This file manages the translation entries for the IBM Calgary IOMMU.
 *
 * Derived from arch/powerpc/platforms/pseries/iommu.c
 *
 * Copyright (C) IBM Corporation, 2006
 *
 * Author: Jon Mason <[email protected]>
 * Author: Muli Ben-Yehuda <[email protected]>
 *
 * 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 program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/bootmem.h>
#include <asm/tce.h>
#include <asm/calgary.h>
#include <asm/proto.h>
#include <asm/cacheflush.h>

/* flush a tce at 'tceaddr' to main memory */
static inline void flush_tce(void* tceaddr)
{
    /* a single tce can't cross a cache line */
    if (cpu_has_clflush)
        clflush(tceaddr);
    else
        wbinvd();
}

void tce_build(struct iommu_table *tbl, unsigned long index,
    unsigned int npages, unsigned long uaddr, int direction)
{
    u64* tp;
    u64 t;
    u64 rpn;

    t = (1 << TCE_READ_SHIFT);
    if (direction != DMA_TO_DEVICE)
        t |= (1 << TCE_WRITE_SHIFT);

    tp = ((u64*)tbl->it_base) + index;

    while (npages--) {
        rpn = (virt_to_bus((void*)uaddr)) >> PAGE_SHIFT;
        t &= ~TCE_RPN_MASK;
        t |= (rpn << TCE_RPN_SHIFT);

        *tp = cpu_to_be64(t);
        flush_tce(tp);

        uaddr += PAGE_SIZE;
        tp++;
    }
}

void tce_free(struct iommu_table *tbl, long index, unsigned int npages)
{
    u64* tp;

    tp  = ((u64*)tbl->it_base) + index;

    while (npages--) {
        *tp = cpu_to_be64(0);
        flush_tce(tp);
        tp++;
    }
}

static inline unsigned int table_size_to_number_of_entries(unsigned char size)
{
    /*
     * size is the order of the table, 0-7
     * smallest table is 8K entries, so shift result by 13 to
     * multiply by 8K
     */
    return (1 << size) << 13;
}

static int tce_table_setparms(struct pci_dev *dev, struct iommu_table *tbl)
{
    unsigned int bitmapsz;
    unsigned long bmppages;
    int ret;

    tbl->it_busno = dev->bus->number;

    /* set the tce table size - measured in entries */
    tbl->it_size = table_size_to_number_of_entries(specified_table_size);

    /*
     * number of bytes needed for the bitmap size in number of
     * entries; we need one bit per entry
     */
    bitmapsz = tbl->it_size / BITS_PER_BYTE;
    bmppages = __get_free_pages(GFP_KERNEL, get_order(bitmapsz));
    if (!bmppages) {
        printk(KERN_ERR "Calgary: cannot allocate bitmap\n");
        ret = -ENOMEM;
        goto done;
    }

    tbl->it_map = (unsigned long*)bmppages;

    memset(tbl->it_map, 0, bitmapsz);

    tbl->it_hint = 0;

    spin_lock_init(&tbl->it_lock);

    return 0;

done:
    return ret;
}

int __init build_tce_table(struct pci_dev *dev, void __iomem *bbar)
{
    struct iommu_table *tbl;
    int ret;

    if (pci_iommu(dev->bus)) {
        printk(KERN_ERR "Calgary: dev %p has sysdata->iommu %p\n",
               dev, pci_iommu(dev->bus));
        BUG();
    }

    tbl = kzalloc(sizeof(struct iommu_table), GFP_KERNEL);
    if (!tbl) {
        printk(KERN_ERR "Calgary: error allocating iommu_table\n");
        ret = -ENOMEM;
        goto done;
    }

    ret = tce_table_setparms(dev, tbl);
    if (ret)
        goto free_tbl;

    tbl->bbar = bbar;

    set_pci_iommu(dev->bus, tbl);

    return 0;

free_tbl:
    kfree(tbl);
done:
    return ret;
}

void * __init alloc_tce_table(void)
{
    unsigned int size;

    size = table_size_to_number_of_entries(specified_table_size);
    size *= TCE_ENTRY_SIZE;

    return __alloc_bootmem_low(size, size, 0);
}

void __init free_tce_table(void *tbl)
{
    unsigned int size;

    if (!tbl)
        return;

    size = table_size_to_number_of_entries(specified_table_size);
    size *= TCE_ENTRY_SIZE;

    free_bootmem(__pa(tbl), size);
}