/*
 * 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 "psb_drv.h"


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

/**
 *      psb_gtt_mask_pte        -       generate GART pte entry
 *      @pfn: page number to encode
 *      @type: type of memory in the GART
 *
 *      Set the GART 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;

        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 GART entries for a gtt_range
 *      @dev: our DRM device
 *      @r: our GTT range
 * 
 *      Given a gtt_range object return the GART offset of the page table
 *      entries for this gtt_range
 */
u32 *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 GART
 *      @dev: our DRM device
 *      @r: our GTT range
 *
 *      Take our preallocated GTT range and insert the GEM object into
 *      the GART.
 *
 *      FIXME: gtt lock ?
 */
static int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 *gtt_slot, pte;
        int numpages = (r->resource.end + 1 - r->resource.start) >> PAGE_SHIFT;
        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;

        /* Make sure we have no alias present */
        wbinvd();

        /* Write our page entries into the GART itself */
        for (i = 0; i < numpages; i++) {
                pte = psb_gtt_mask_pte(page_to_pfn(*pages++), 0/*type*/);
                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 GART
 *      @dev: our DRM device
 *      @r: our GTT range
 *
 *      Remove a preallocated GTT range from the GART. Overwrite all the
 *      page table entries with the dummy page
 */

static void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 *gtt_slot, pte;
        int numpages = (r->resource.end + 1 - r->resource.start) >> PAGE_SHIFT;
        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 < numpages; i++)
                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
 *
 *      FIXME: Do we need to cache flush when we update the GTT
 */
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->resource.end + 1 - gt->resource.start) >> PAGE_SHIFT;

        WARN_ON(gt->pages);

        /* This is the shared memory object that backs the GEM resource */
        inode = gt->gem.filp->f_path.dentry->d_inode;
        mapping = inode->i_mapping;

        gt->pages = kmalloc(pages * sizeof(struct page *), GFP_KERNEL);
        if (gt->pages == NULL)
                return -ENOMEM;
        for (i = 0; i < pages; i++) {
                /* FIXME: review flags later */
                p = read_cache_page_gfp(mapping, i,
                                        __GFP_COLD | GFP_KERNEL);
                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 GART as they could now be paged out
 *      and move bus address.
 *
 *      FIXME: Do we need to cache flush when we update the GTT
 */
static void psb_gtt_detach_pages(struct gtt_range *gt)
{
        int i;
        int pages = (gt->resource.end + 1 - gt->resource.start) >> PAGE_SHIFT;

        for (i = 0; i < pages; i++) {
                /* FIXME: do we need to force dirty */
                set_page_dirty(gt->pages[i]);
                /* Undo the reference we took when populating the table */
                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;
        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);
                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->pg->stolen_size - 1;
        } else {
                /* The rest we will use for GEM backed objects */
                start = r->start + dev_priv->pg->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;
        /* Ensure this is set for non GEM objects */
        gt->gem.dev = dev;
        kref_init(&gt->kref);

        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_destroy         -       final free up of a gtt
 *      @kref: the kref of the gtt
 *
 *      Called from the kernel kref put when the final reference to our
 *      GTT object is dropped. At that point we can free up the resources.
 *
 *      For now we handle mmap clean up here to work around limits in GEM
 */
static void psb_gtt_destroy(struct kref *kref)
{
        struct gtt_range *gt = container_of(kref, struct gtt_range, kref);

        /* 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);
}

/**
 *      psb_gtt_kref_put        -       drop reference to a GTT object
 *      @gt: the GT being dropped
 *
 *      Drop a reference to a psb gtt
 */
void psb_gtt_kref_put(struct gtt_range *gt)
{
        kref_put(&gt->kref, psb_gtt_destroy);
}

/**
 *      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
 */
void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt)
{
        psb_gtt_kref_put(gt);
}


struct psb_gtt *psb_gtt_alloc(struct drm_device *dev)
{
        struct psb_gtt *tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);

        if (!tmp)
                return NULL;

        init_rwsem(&tmp->sem);
        tmp->dev = dev;

        return tmp;
}

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

        /* FIXME: iounmap dev_priv->vram_addr etc */
        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);
        }
        kfree(dev_priv->pg);
        dev_priv->pg = NULL;
}

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;
        uint32_t vram_pages;
        uint32_t tt_pages;
        uint32_t *ttm_gtt_map;
        uint32_t dvmt_mode = 0;
        struct psb_gtt *pg;

        int ret = 0;
        uint32_t pte;

        mutex_init(&dev_priv->gtt_mutex);

        dev_priv->pg = pg = psb_gtt_alloc(dev);
        if (pg == NULL)
                return -ENOMEM;

        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_mem = &dev->pdev->resource[PSB_GATT_RESOURCE];

        dev_priv->gtt_initialized = 1;

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

        pg->gatt_start = pci_resource_start(dev->pdev, PSB_GATT_RESOURCE);
        /* fix me: video mmu has hw bug to access 0x0D0000000,
         * then make gatt start at 0x0e000,0000 */
        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;
        pg->gatt_pages = pci_resource_len(dev->pdev, PSB_GATT_RESOURCE)
            >> PAGE_SHIFT;

        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;

        printk(KERN_INFO"GMMADR(region 0) start: 0x%08x (%dM).\n",
                pg->gatt_start, pg->gatt_pages/256);
        printk(KERN_INFO"GTTADR(region 3) start: 0x%08x (can map %dM RAM), and actual RAM base 0x%08x.\n",
                pg->gtt_start, gtt_pages * 4, pg->gtt_phys_start);
        printk(KERN_INFO "Stolen memory information\n");
        printk(KERN_INFO "       base in RAM: 0x%x\n", dev_priv->stolen_base);
        printk(KERN_INFO "       size: %luK, calculated by (GTT RAM base) - (Stolen base), seems wrong\n",
                vram_stolen_size/1024);
        dvmt_mode = (dev_priv->gmch_ctrl >> 4) & 0x7;
        printk(KERN_INFO "      the correct size should be: %dM(dvmt mode=%d)\n",
                (dvmt_mode == 1) ? 1 : (2 << (dvmt_mode - 1)), dvmt_mode);

        if (resume && (gtt_pages != pg->gtt_pages) &&
            (stolen_size != pg->stolen_size)) {
                DRM_ERROR("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;
        dev_priv->gtt_map =
            ioremap_nocache(pg->gtt_phys_start, gtt_pages << PAGE_SHIFT);
        if (!dev_priv->gtt_map) {
                DRM_ERROR("Failure to map gtt.\n");
                ret = -ENOMEM;
                goto out_err;
        }

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

        DRM_DEBUG("%s: vram kernel virtual address %p\n", dev_priv->vram_addr);

        tt_pages = (pg->gatt_pages < PSB_TT_PRIV0_PLIMIT) ?
                (pg->gatt_pages) : PSB_TT_PRIV0_PLIMIT;

        ttm_gtt_map = dev_priv->gtt_map + tt_pages / 2;

        /*
         * insert vram stolen pages.
         */

        pfn_base = dev_priv->stolen_base >> PAGE_SHIFT;
        vram_pages = num_pages = vram_stolen_size >> PAGE_SHIFT;
        printk(KERN_INFO"Set up %d stolen pages starting at 0x%08x, GTT offset %dK\n",
                num_pages, pfn_base, 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 managed by IMG.
         */
        pfn_base = page_to_pfn(dev_priv->scratch_page);
        pte = psb_gtt_mask_pte(pfn_base, 0);
        for (; i < tt_pages / 2 - 1; ++i)
                iowrite32(pte, dev_priv->gtt_map + i);

        /*
         * Init rest of gtt managed by TTM.
         */

        pfn_base = page_to_pfn(dev_priv->scratch_page);
        pte = psb_gtt_mask_pte(pfn_base, 0);
        PSB_DEBUG_INIT("Initializing the rest of a total "
                       "of %d gtt pages.\n", pg->gatt_pages);

        for (; i < pg->gatt_pages - tt_pages / 2; ++i)
                iowrite32(pte, ttm_gtt_map + i);
        (void) ioread32(dev_priv->gtt_map + i - 1);

        return 0;

out_err:
        psb_gtt_takedown(dev);
        return ret;
}