i915_gem_stolen.c

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/*
 * Copyright © 2008-2012 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eric Anholt <[email protected]>
 *    Chris Wilson <[email protected]>
 *
 */

#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"

/*
 * The BIOS typically reserves some of the system's memory for the exclusive
 * use of the integrated graphics. This memory is no longer available for
 * use by the OS and so the user finds that his system has less memory
 * available than he put in. We refer to this memory as stolen.
 *
 * The BIOS will allocate its framebuffer from the stolen memory. Our
 * goal is try to reuse that object for our own fbcon which must always
 * be available for panics. Anything else we can reuse the stolen memory
 * for is a boon.
 */

#define PTE_ADDRESS_MASK        0xfffff000
#define PTE_ADDRESS_MASK_HIGH       0x000000f0 /* i915+ */
#define PTE_MAPPING_TYPE_UNCACHED   (0 << 1)
#define PTE_MAPPING_TYPE_DCACHE     (1 << 1) /* i830 only */
#define PTE_MAPPING_TYPE_CACHED     (3 << 1)
#define PTE_MAPPING_TYPE_MASK       (3 << 1)
#define PTE_VALID           (1 << 0)

static unsigned long i915_stolen_to_phys(struct drm_device *dev, u32 offset)
{
    struct drm_i915_private *dev_priv = dev->dev_private;
    struct pci_dev *pdev = dev_priv->bridge_dev;
    u32 base;

#if 0
    /* On the machines I have tested the Graphics Base of Stolen Memory
     * is unreliable, so compute the base by subtracting the stolen memory
     * from the Top of Low Usable DRAM which is where the BIOS places
     * the graphics stolen memory.
     */
    if (INTEL_INFO(dev)->gen > 3 || IS_G33(dev)) {
        /* top 32bits are reserved = 0 */
        pci_read_config_dword(pdev, 0xA4, &base);
    } else {
        /* XXX presume 8xx is the same as i915 */
        pci_bus_read_config_dword(pdev->bus, 2, 0x5C, &base);
    }
#else
    if (INTEL_INFO(dev)->gen > 3 || IS_G33(dev)) {
        u16 val;
        pci_read_config_word(pdev, 0xb0, &val);
        base = val >> 4 << 20;
    } else {
        u8 val;
        pci_read_config_byte(pdev, 0x9c, &val);
        base = val >> 3 << 27;
    }
    base -= dev_priv->mm.gtt->stolen_size;
#endif

    return base + offset;
}

static void i915_warn_stolen(struct drm_device *dev)
{
    DRM_INFO("not enough stolen space for compressed buffer, disabling\n");
    DRM_INFO("hint: you may be able to increase stolen memory size in the BIOS to avoid this\n");
}

static void i915_setup_compression(struct drm_device *dev, int size)
{
    struct drm_i915_private *dev_priv = dev->dev_private;
    struct drm_mm_node *compressed_fb, *uninitialized_var(compressed_llb);
    unsigned long cfb_base;
    unsigned long ll_base = 0;

    /* Just in case the BIOS is doing something questionable. */
    intel_disable_fbc(dev);

    compressed_fb = drm_mm_search_free(&dev_priv->mm.stolen, size, 4096, 0);
    if (compressed_fb)
        compressed_fb = drm_mm_get_block(compressed_fb, size, 4096);
    if (!compressed_fb)
        goto err;

    cfb_base = i915_stolen_to_phys(dev, compressed_fb->start);
    if (!cfb_base)
        goto err_fb;

    if (!(IS_GM45(dev) || HAS_PCH_SPLIT(dev))) {
        compressed_llb = drm_mm_search_free(&dev_priv->mm.stolen,
                            4096, 4096, 0);
        if (compressed_llb)
            compressed_llb = drm_mm_get_block(compressed_llb,
                              4096, 4096);
        if (!compressed_llb)
            goto err_fb;

        ll_base = i915_stolen_to_phys(dev, compressed_llb->start);
        if (!ll_base)
            goto err_llb;
    }

    dev_priv->cfb_size = size;

    dev_priv->compressed_fb = compressed_fb;
    if (HAS_PCH_SPLIT(dev))
        I915_WRITE(ILK_DPFC_CB_BASE, compressed_fb->start);
    else if (IS_GM45(dev)) {
        I915_WRITE(DPFC_CB_BASE, compressed_fb->start);
    } else {
        I915_WRITE(FBC_CFB_BASE, cfb_base);
        I915_WRITE(FBC_LL_BASE, ll_base);
        dev_priv->compressed_llb = compressed_llb;
    }

    DRM_DEBUG_KMS("FBC base 0x%08lx, ll base 0x%08lx, size %dM\n",
              cfb_base, ll_base, size >> 20);
    return;

err_llb:
    drm_mm_put_block(compressed_llb);
err_fb:
    drm_mm_put_block(compressed_fb);
err:
    dev_priv->no_fbc_reason = FBC_STOLEN_TOO_SMALL;
    i915_warn_stolen(dev);
}

static void i915_cleanup_compression(struct drm_device *dev)
{
    struct drm_i915_private *dev_priv = dev->dev_private;

    drm_mm_put_block(dev_priv->compressed_fb);
    if (dev_priv->compressed_llb)
        drm_mm_put_block(dev_priv->compressed_llb);
}

void i915_gem_cleanup_stolen(struct drm_device *dev)
{
    if (I915_HAS_FBC(dev) && i915_powersave)
        i915_cleanup_compression(dev);
}

int i915_gem_init_stolen(struct drm_device *dev)
{
    struct drm_i915_private *dev_priv = dev->dev_private;
    unsigned long prealloc_size = dev_priv->mm.gtt->stolen_size;

    /* Basic memrange allocator for stolen space */
    drm_mm_init(&dev_priv->mm.stolen, 0, prealloc_size);

    /* Try to set up FBC with a reasonable compressed buffer size */
    if (I915_HAS_FBC(dev) && i915_powersave) {
        int cfb_size;

        /* Leave 1M for line length buffer & misc. */

        /* Try to get a 32M buffer... */
        if (prealloc_size > (36*1024*1024))
            cfb_size = 32*1024*1024;
        else /* fall back to 7/8 of the stolen space */
            cfb_size = prealloc_size * 7 / 8;
        i915_setup_compression(dev, cfb_size);
    }

    return 0;
}