acpi-ext.c

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/*
 * (c) Copyright 2003, 2006 Hewlett-Packard Development Company, L.P.
 *  Alex Williamson <[email protected]>
 *  Bjorn Helgaas <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/acpi.h>

#include <asm/acpi-ext.h>

/*
 * Device CSRs that do not appear in PCI config space should be described
 * via ACPI.  This would normally be done with Address Space Descriptors
 * marked as "consumer-only," but old versions of Windows and Linux ignore
 * the producer/consumer flag, so HP invented a vendor-defined resource to
 * describe the location and size of CSR space.
 */

struct acpi_vendor_uuid hp_ccsr_uuid = {
    .subtype = 2,
    .data = { 0xf9, 0xad, 0xe9, 0x69, 0x4f, 0x92, 0x5f, 0xab, 0xf6, 0x4a,
        0x24, 0xd2, 0x01, 0x37, 0x0e, 0xad },
};

static acpi_status hp_ccsr_locate(acpi_handle obj, u64 *base, u64 *length)
{
    acpi_status status;
    struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
    struct acpi_resource *resource;
    struct acpi_resource_vendor_typed *vendor;

    status = acpi_get_vendor_resource(obj, METHOD_NAME__CRS, &hp_ccsr_uuid,
        &buffer);

    resource = buffer.pointer;
    vendor = &resource->data.vendor_typed;

    if (ACPI_FAILURE(status) || vendor->byte_length < 16) {
        status = AE_NOT_FOUND;
        goto exit;
    }

    memcpy(base, vendor->byte_data, sizeof(*base));
    memcpy(length, vendor->byte_data + 8, sizeof(*length));

  exit:
    kfree(buffer.pointer);
    return status;
}

struct csr_space {
    u64 base;
    u64 length;
};

static acpi_status find_csr_space(struct acpi_resource *resource, void *data)
{
    struct csr_space *space = data;
    struct acpi_resource_address64 addr;
    acpi_status status;

    status = acpi_resource_to_address64(resource, &addr);
    if (ACPI_SUCCESS(status) &&
        addr.resource_type == ACPI_MEMORY_RANGE &&
        addr.address_length &&
        addr.producer_consumer == ACPI_CONSUMER) {
        space->base = addr.minimum;
        space->length = addr.address_length;
        return AE_CTRL_TERMINATE;
    }
    return AE_OK;       /* keep looking */
}

static acpi_status hp_crs_locate(acpi_handle obj, u64 *base, u64 *length)
{
    struct csr_space space = { 0, 0 };

    acpi_walk_resources(obj, METHOD_NAME__CRS, find_csr_space, &space);
    if (!space.length)
        return AE_NOT_FOUND;

    *base = space.base;
    *length = space.length;
    return AE_OK;
}

acpi_status hp_acpi_csr_space(acpi_handle obj, u64 *csr_base, u64 *csr_length)
{
    acpi_status status;

    status = hp_ccsr_locate(obj, csr_base, csr_length);
    if (ACPI_SUCCESS(status))
        return status;

    return hp_crs_locate(obj, csr_base, csr_length);
}
EXPORT_SYMBOL(hp_acpi_csr_space);