/*
 * Copyright (c) 2007, Intel Corporation.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 * Authors: Thomas Hellstrom <thomas-at-tungstengraphics.com>
 *          Alan Cox <alan@linux.intel.com>
 */

#include <drm/drmP.h>
#include <linux/shmem_fs.h>
#include "psb_drv.h"


/*
 *      GTT resource allocator - manage page mappings in GTT space
 */

/**
 *      psb_gtt_mask_pte        -       generate GTT pte entry
 *      @pfn: page number to encode
 *      @type: type of memory in the GTT
 *
 *      Set the GTT entry for the appropriate memory type.
 */
static inline uint32_t psb_gtt_mask_pte(uint32_t pfn, int type)
{
        uint32_t mask = PSB_PTE_VALID;

        /* Ensure we explode rather than put an invalid low mapping of
           a high mapping page into the gtt */
        BUG_ON(pfn & ~(0xFFFFFFFF >> PAGE_SHIFT));

        if (type & PSB_MMU_CACHED_MEMORY)
                mask |= PSB_PTE_CACHED;
        if (type & PSB_MMU_RO_MEMORY)
                mask |= PSB_PTE_RO;
        if (type & PSB_MMU_WO_MEMORY)
                mask |= PSB_PTE_WO;

        return (pfn << PAGE_SHIFT) | mask;
}

/**
 *      psb_gtt_entry           -       find the GTT entries for a gtt_range
 *      @dev: our DRM device
 *      @r: our GTT range
 *
 *      Given a gtt_range object return the GTT offset of the page table
 *      entries for this gtt_range
 */
static u32 __iomem *psb_gtt_entry(struct drm_device *dev, struct gtt_range *r)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        unsigned long offset;

        offset = r->resource.start - dev_priv->gtt_mem->start;

        return dev_priv->gtt_map + (offset >> PAGE_SHIFT);
}

/**
 *      psb_gtt_insert  -       put an object into the GTT
 *      @dev: our DRM device
 *      @r: our GTT range
 *
 *      Take our preallocated GTT range and insert the GEM object into
 *      the GTT. This is protected via the gtt mutex which the caller
 *      must hold.
 */
static int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r,
                          int resume)
{
        u32 __iomem *gtt_slot;
        u32 pte;
        struct page **pages;
        int i;

        if (r->pages == NULL) {
                WARN_ON(1);
                return -EINVAL;
        }

        WARN_ON(r->stolen);     /* refcount these maybe ? */

        gtt_slot = psb_gtt_entry(dev, r);
        pages = r->pages;

        if (!resume) {
                /* Make sure changes are visible to the GPU */
                set_pages_array_wc(pages, r->npage);
        }

        /* Write our page entries into the GTT itself */
        for (i = r->roll; i < r->npage; i++) {
                pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]), 0);
                iowrite32(pte, gtt_slot++);
        }
        for (i = 0; i < r->roll; i++) {
                pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]), 0);
                iowrite32(pte, gtt_slot++);
        }
        /* Make sure all the entries are set before we return */
        ioread32(gtt_slot - 1);

        return 0;
}

/**
 *      psb_gtt_remove  -       remove an object from the GTT
 *      @dev: our DRM device
 *      @r: our GTT range
 *
 *      Remove a preallocated GTT range from the GTT. Overwrite all the
 *      page table entries with the dummy page. This is protected via the gtt
 *      mutex which the caller must hold.
 */
static void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 __iomem *gtt_slot;
        u32 pte;
        int i;

        WARN_ON(r->stolen);

        gtt_slot = psb_gtt_entry(dev, r);
        pte = psb_gtt_mask_pte(page_to_pfn(dev_priv->scratch_page), 0);

        for (i = 0; i < r->npage; i++)
                iowrite32(pte, gtt_slot++);
        ioread32(gtt_slot - 1);
        set_pages_array_wb(r->pages, r->npage);
}

/**
 *      psb_gtt_roll    -       set scrolling position
 *      @dev: our DRM device
 *      @r: the gtt mapping we are using
 *      @roll: roll offset
 *
 *      Roll an existing pinned mapping by moving the pages through the GTT.
 *      This allows us to implement hardware scrolling on the consoles without
 *      a 2D engine
 */
void psb_gtt_roll(struct drm_device *dev, struct gtt_range *r, int roll)
{
        u32 __iomem *gtt_slot;
        u32 pte;
        int i;

        if (roll >= r->npage) {
                WARN_ON(1);
                return;
        }

        r->roll = roll;

        /* Not currently in the GTT - no worry we will write the mapping at
           the right position when it gets pinned */
        if (!r->stolen && !r->in_gart)
                return;

        gtt_slot = psb_gtt_entry(dev, r);

        for (i = r->roll; i < r->npage; i++) {
                pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]), 0);
                iowrite32(pte, gtt_slot++);
        }
        for (i = 0; i < r->roll; i++) {
                pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]), 0);
                iowrite32(pte, gtt_slot++);
        }
        ioread32(gtt_slot - 1);
}

/**
 *      psb_gtt_attach_pages    -       attach and pin GEM pages
 *      @gt: the gtt range
 *
 *      Pin and build an in kernel list of the pages that back our GEM object.
 *      While we hold this the pages cannot be swapped out. This is protected
 *      via the gtt mutex which the caller must hold.
 */
static int psb_gtt_attach_pages(struct gtt_range *gt)
{
        struct inode *inode;
        struct address_space *mapping;
        int i;
        struct page *p;
        int pages = gt->gem.size / PAGE_SIZE;

        WARN_ON(gt->pages);

        /* This is the shared memory object that backs the GEM resource */
        inode = file_inode(gt->gem.filp);
        mapping = inode->i_mapping;

        gt->pages = kmalloc(pages * sizeof(struct page *), GFP_KERNEL);
        if (gt->pages == NULL)
                return -ENOMEM;
        gt->npage = pages;

        for (i = 0; i < pages; i++) {
                p = shmem_read_mapping_page(mapping, i);
                if (IS_ERR(p))
                        goto err;
                gt->pages[i] = p;
        }
        return 0;

err:
        while (i--)
                page_cache_release(gt->pages[i]);
        kfree(gt->pages);
        gt->pages = NULL;
        return PTR_ERR(p);
}

/**
 *      psb_gtt_detach_pages    -       attach and pin GEM pages
 *      @gt: the gtt range
 *
 *      Undo the effect of psb_gtt_attach_pages. At this point the pages
 *      must have been removed from the GTT as they could now be paged out
 *      and move bus address. This is protected via the gtt mutex which the
 *      caller must hold.
 */
static void psb_gtt_detach_pages(struct gtt_range *gt)
{
        int i;
        for (i = 0; i < gt->npage; i++) {
                /* FIXME: do we need to force dirty */
                set_page_dirty(gt->pages[i]);
                page_cache_release(gt->pages[i]);
        }
        kfree(gt->pages);
        gt->pages = NULL;
}

/**
 *      psb_gtt_pin             -       pin pages into the GTT
 *      @gt: range to pin
 *
 *      Pin a set of pages into the GTT. The pins are refcounted so that
 *      multiple pins need multiple unpins to undo.
 *
 *      Non GEM backed objects treat this as a no-op as they are always GTT
 *      backed objects.
 */
int psb_gtt_pin(struct gtt_range *gt)
{
        int ret = 0;
        struct drm_device *dev = gt->gem.dev;
        struct drm_psb_private *dev_priv = dev->dev_private;

        mutex_lock(&dev_priv->gtt_mutex);

        if (gt->in_gart == 0 && gt->stolen == 0) {
                ret = psb_gtt_attach_pages(gt);
                if (ret < 0)
                        goto out;
                ret = psb_gtt_insert(dev, gt, 0);
                if (ret < 0) {
                        psb_gtt_detach_pages(gt);
                        goto out;
                }
        }
        gt->in_gart++;
out:
        mutex_unlock(&dev_priv->gtt_mutex);
        return ret;
}

/**
 *      psb_gtt_unpin           -       Drop a GTT pin requirement
 *      @gt: range to pin
 *
 *      Undoes the effect of psb_gtt_pin. On the last drop the GEM object
 *      will be removed from the GTT which will also drop the page references
 *      and allow the VM to clean up or page stuff.
 *
 *      Non GEM backed objects treat this as a no-op as they are always GTT
 *      backed objects.
 */
void psb_gtt_unpin(struct gtt_range *gt)
{
        struct drm_device *dev = gt->gem.dev;
        struct drm_psb_private *dev_priv = dev->dev_private;

        mutex_lock(&dev_priv->gtt_mutex);

        WARN_ON(!gt->in_gart);

        gt->in_gart--;
        if (gt->in_gart == 0 && gt->stolen == 0) {
                psb_gtt_remove(dev, gt);
                psb_gtt_detach_pages(gt);
        }
        mutex_unlock(&dev_priv->gtt_mutex);
}

/*
 *      GTT resource allocator - allocate and manage GTT address space
 */

/**
 *      psb_gtt_alloc_range     -       allocate GTT address space
 *      @dev: Our DRM device
 *      @len: length (bytes) of address space required
 *      @name: resource name
 *      @backed: resource should be backed by stolen pages
 *
 *      Ask the kernel core to find us a suitable range of addresses
 *      to use for a GTT mapping.
 *
 *      Returns a gtt_range structure describing the object, or NULL on
 *      error. On successful return the resource is both allocated and marked
 *      as in use.
 */
struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,
                                                const char *name, int backed)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct gtt_range *gt;
        struct resource *r = dev_priv->gtt_mem;
        int ret;
        unsigned long start, end;

        if (backed) {
                /* The start of the GTT is the stolen pages */
                start = r->start;
                end = r->start + dev_priv->gtt.stolen_size - 1;
        } else {
                /* The rest we will use for GEM backed objects */
                start = r->start + dev_priv->gtt.stolen_size;
                end = r->end;
        }

        gt = kzalloc(sizeof(struct gtt_range), GFP_KERNEL);
        if (gt == NULL)
                return NULL;
        gt->resource.name = name;
        gt->stolen = backed;
        gt->in_gart = backed;
        gt->roll = 0;
        /* Ensure this is set for non GEM objects */
        gt->gem.dev = dev;
        ret = allocate_resource(dev_priv->gtt_mem, &gt->resource,
                                len, start, end, PAGE_SIZE, NULL, NULL);
        if (ret == 0) {
                gt->offset = gt->resource.start - r->start;
                return gt;
        }
        kfree(gt);
        return NULL;
}

/**
 *      psb_gtt_free_range      -       release GTT address space
 *      @dev: our DRM device
 *      @gt: a mapping created with psb_gtt_alloc_range
 *
 *      Release a resource that was allocated with psb_gtt_alloc_range. If the
 *      object has been pinned by mmap users we clean this up here currently.
 */
void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt)
{
        /* Undo the mmap pin if we are destroying the object */
        if (gt->mmapping) {
                psb_gtt_unpin(gt);
                gt->mmapping = 0;
        }
        WARN_ON(gt->in_gart && !gt->stolen);
        release_resource(&gt->resource);
        kfree(gt);
}

static void psb_gtt_alloc(struct drm_device *dev)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        init_rwsem(&dev_priv->gtt.sem);
}

void psb_gtt_takedown(struct drm_device *dev)
{
        struct drm_psb_private *dev_priv = dev->dev_private;

        if (dev_priv->gtt_map) {
                iounmap(dev_priv->gtt_map);
                dev_priv->gtt_map = NULL;
        }
        if (dev_priv->gtt_initialized) {
                pci_write_config_word(dev->pdev, PSB_GMCH_CTRL,
                                      dev_priv->gmch_ctrl);
                PSB_WVDC32(dev_priv->pge_ctl, PSB_PGETBL_CTL);
                (void) PSB_RVDC32(PSB_PGETBL_CTL);
        }
        if (dev_priv->vram_addr)
                iounmap(dev_priv->gtt_map);
}

int psb_gtt_init(struct drm_device *dev, int resume)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        unsigned gtt_pages;
        unsigned long stolen_size, vram_stolen_size;
        unsigned i, num_pages;
        unsigned pfn_base;
        struct psb_gtt *pg;

        int ret = 0;
        uint32_t pte;

        if (!resume) {
                mutex_init(&dev_priv->gtt_mutex);
                psb_gtt_alloc(dev);
        }

        pg = &dev_priv->gtt;

        /* Enable the GTT */
        pci_read_config_word(dev->pdev, PSB_GMCH_CTRL, &dev_priv->gmch_ctrl);
        pci_write_config_word(dev->pdev, PSB_GMCH_CTRL,
                              dev_priv->gmch_ctrl | _PSB_GMCH_ENABLED);

        dev_priv->pge_ctl = PSB_RVDC32(PSB_PGETBL_CTL);
        PSB_WVDC32(dev_priv->pge_ctl | _PSB_PGETBL_ENABLED, PSB_PGETBL_CTL);
        (void) PSB_RVDC32(PSB_PGETBL_CTL);

        /* The root resource we allocate address space from */
        dev_priv->gtt_initialized = 1;

        pg->gtt_phys_start = dev_priv->pge_ctl & PAGE_MASK;

        /*
         *      The video mmu has a hw bug when accessing 0x0D0000000.
         *      Make gatt start at 0x0e000,0000. This doesn't actually
         *      matter for us but may do if the video acceleration ever
         *      gets opened up.
         */
        pg->mmu_gatt_start = 0xE0000000;

        pg->gtt_start = pci_resource_start(dev->pdev, PSB_GTT_RESOURCE);
        gtt_pages = pci_resource_len(dev->pdev, PSB_GTT_RESOURCE)
                                                                >> PAGE_SHIFT;
        /* CDV doesn't report this. In which case the system has 64 gtt pages */
        if (pg->gtt_start == 0 || gtt_pages == 0) {
                dev_dbg(dev->dev, "GTT PCI BAR not initialized.\n");
                gtt_pages = 64;
                pg->gtt_start = dev_priv->pge_ctl;
        }

        pg->gatt_start = pci_resource_start(dev->pdev, PSB_GATT_RESOURCE);
        pg->gatt_pages = pci_resource_len(dev->pdev, PSB_GATT_RESOURCE)
                                                                >> PAGE_SHIFT;
        dev_priv->gtt_mem = &dev->pdev->resource[PSB_GATT_RESOURCE];

        if (pg->gatt_pages == 0 || pg->gatt_start == 0) {
                static struct resource fudge;   /* Preferably peppermint */
                /* This can occur on CDV systems. Fudge it in this case.
                   We really don't care what imaginary space is being allocated
                   at this point */
                dev_dbg(dev->dev, "GATT PCI BAR not initialized.\n");
                pg->gatt_start = 0x40000000;
                pg->gatt_pages = (128 * 1024 * 1024) >> PAGE_SHIFT;
                /* This is a little confusing but in fact the GTT is providing
                   a view from the GPU into memory and not vice versa. As such
                   this is really allocating space that is not the same as the
                   CPU address space on CDV */
                fudge.start = 0x40000000;
                fudge.end = 0x40000000 + 128 * 1024 * 1024 - 1;
                fudge.name = "fudge";
                fudge.flags = IORESOURCE_MEM;
                dev_priv->gtt_mem = &fudge;
        }

        pci_read_config_dword(dev->pdev, PSB_BSM, &dev_priv->stolen_base);
        vram_stolen_size = pg->gtt_phys_start - dev_priv->stolen_base
                                                                - PAGE_SIZE;

        stolen_size = vram_stolen_size;

        dev_dbg(dev->dev, "Stolen memory base 0x%x, size %luK\n",
                        dev_priv->stolen_base, vram_stolen_size / 1024);

        if (resume && (gtt_pages != pg->gtt_pages) &&
            (stolen_size != pg->stolen_size)) {
                dev_err(dev->dev, "GTT resume error.\n");
                ret = -EINVAL;
                goto out_err;
        }

        pg->gtt_pages = gtt_pages;
        pg->stolen_size = stolen_size;
        dev_priv->vram_stolen_size = vram_stolen_size;

        /*
         *      Map the GTT and the stolen memory area
         */
        if (!resume)
                dev_priv->gtt_map = ioremap_nocache(pg->gtt_phys_start,
                                                gtt_pages << PAGE_SHIFT);
        if (!dev_priv->gtt_map) {
                dev_err(dev->dev, "Failure to map gtt.\n");
                ret = -ENOMEM;
                goto out_err;
        }

        if (!resume)
                dev_priv->vram_addr = ioremap_wc(dev_priv->stolen_base,
                                                 stolen_size);
        if (!dev_priv->vram_addr) {
                dev_err(dev->dev, "Failure to map stolen base.\n");
                ret = -ENOMEM;
                goto out_err;
        }

        /*
         * Insert vram stolen pages into the GTT
         */

        pfn_base = dev_priv->stolen_base >> PAGE_SHIFT;
        num_pages = vram_stolen_size >> PAGE_SHIFT;
        dev_dbg(dev->dev, "Set up %d stolen pages starting at 0x%08x, GTT offset %dK\n",
                num_pages, pfn_base << PAGE_SHIFT, 0);
        for (i = 0; i < num_pages; ++i) {
                pte = psb_gtt_mask_pte(pfn_base + i, 0);
                iowrite32(pte, dev_priv->gtt_map + i);
        }

        /*
         * Init rest of GTT to the scratch page to avoid accidents or scribbles
         */

        pfn_base = page_to_pfn(dev_priv->scratch_page);
        pte = psb_gtt_mask_pte(pfn_base, 0);
        for (; i < gtt_pages; ++i)
                iowrite32(pte, dev_priv->gtt_map + i);

        (void) ioread32(dev_priv->gtt_map + i - 1);
        return 0;

out_err:
        psb_gtt_takedown(dev);
        return ret;
}

int psb_gtt_restore(struct drm_device *dev)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct resource *r = dev_priv->gtt_mem->child;
        struct gtt_range *range;
        unsigned int restored = 0, total = 0, size = 0;

        /* On resume, the gtt_mutex is already initialized */
        mutex_lock(&dev_priv->gtt_mutex);
        psb_gtt_init(dev, 1);

        while (r != NULL) {
                range = container_of(r, struct gtt_range, resource);
                if (range->pages) {
                        psb_gtt_insert(dev, range, 1);
                        size += range->resource.end - range->resource.start;
                        restored++;
                }
                r = r->sibling;
                total++;
        }
        mutex_unlock(&dev_priv->gtt_mutex);
        DRM_DEBUG_DRIVER("Restored %u of %u gtt ranges (%u KB)", restored,
                         total, (size / 1024));

        return 0;
}