ioremap.c

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/*
 *          ioremap.c
 *
 * Support for mapping between dma_addr_t values a phys_addr_t values.
 *
 * Copyright (C) 2005-2009 Scientific-Atlanta, 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 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Author:       David VomLehn <[email protected]>
 *
 * Description:  Defines the platform resources for the SA settop.
 *
 * NOTE: The bootloader allocates persistent memory at an address which is
 * 16 MiB below the end of the highest address in KSEG0. All fixed
 * address memory reservations must avoid this region.
 */

#include <linux/kernel.h>
#include <linux/module.h>

#include <asm/mach-powertv/ioremap.h>

/*
 * Define the sizes of and masks for grains in physical and DMA space. The
 * values are the same but the types are not.
 */
#define IOR_PHYS_GRAIN      ((phys_addr_t) 1 << IOR_LSBITS)
#define IOR_PHYS_GRAIN_MASK (IOR_PHYS_GRAIN - 1)

#define IOR_DMA_GRAIN       ((dma_addr_t) 1 << IOR_LSBITS)
#define IOR_DMA_GRAIN_MASK  (IOR_DMA_GRAIN - 1)

/*
 * Values that, when accessed by an index derived from a phys_addr_t and
 * added to phys_addr_t value, yield a DMA address
 */
struct ior_phys_to_dma _ior_phys_to_dma[IOR_NUM_PHYS_TO_DMA];
EXPORT_SYMBOL(_ior_phys_to_dma);

/*
 * Values that, when accessed by an index derived from a dma_addr_t and
 * added to that dma_addr_t value, yield a physical address
 */
struct ior_dma_to_phys _ior_dma_to_phys[IOR_NUM_DMA_TO_PHYS];
EXPORT_SYMBOL(_ior_dma_to_phys);

static void setup_dma_to_phys(dma_addr_t dma, phys_addr_t delta, dma_addr_t s)
{
    int dma_idx, first_idx, last_idx;
    phys_addr_t first, last;

    /*
     * Calculate the first and last indices, rounding the first up and
     * the second down.
     */
    first = dma & ~IOR_DMA_GRAIN_MASK;
    last = (dma + s - 1) & ~IOR_DMA_GRAIN_MASK;
    first_idx = first >> IOR_LSBITS;        /* Convert to indices */
    last_idx = last >> IOR_LSBITS;

    for (dma_idx = first_idx; dma_idx <= last_idx; dma_idx++)
        _ior_dma_to_phys[dma_idx].offset = delta >> IOR_DMA_SHIFT;
}

static void setup_phys_to_dma(phys_addr_t phys, dma_addr_t delta, phys_addr_t s)
{
    int phys_idx, first_idx, last_idx;
    phys_addr_t first, last;

    /*
     * Calculate the first and last indices, rounding the first up and
     * the second down.
     */
    first = phys & ~IOR_PHYS_GRAIN_MASK;
    last = (phys + s - 1) & ~IOR_PHYS_GRAIN_MASK;
    first_idx = first >> IOR_LSBITS;        /* Convert to indices */
    last_idx = last >> IOR_LSBITS;

    for (phys_idx = first_idx; phys_idx <= last_idx; phys_idx++)
        _ior_phys_to_dma[phys_idx].offset = delta >> IOR_PHYS_SHIFT;
}

void ioremap_add_map(phys_addr_t phys, phys_addr_t dma, phys_addr_t size)
{
    if (size == 0)
        return;

    if ((dma & IOR_DMA_GRAIN_MASK) != 0 ||
        (phys & IOR_PHYS_GRAIN_MASK) != 0 ||
        (size & IOR_PHYS_GRAIN_MASK) != 0)
        pr_crit("Memory allocation must be in chunks of 0x%x bytes\n",
            IOR_PHYS_GRAIN);

    setup_dma_to_phys(dma, phys - dma, size);
    setup_phys_to_dma(phys, dma - phys, size);
}