/**************************************************************************
 *
 * Copyright © 2009-2011 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
 *
 **************************************************************************/

#include "vmwgfx_drv.h"
#include "drmP.h"
#include "ttm/ttm_bo_driver.h"

#define VMW_PPN_SIZE sizeof(unsigned long)

static int vmw_gmr2_bind(struct vmw_private *dev_priv,
                         struct page *pages[],
                         unsigned long num_pages,
                         int gmr_id)
{
        SVGAFifoCmdDefineGMR2 define_cmd;
        SVGAFifoCmdRemapGMR2 remap_cmd;
        uint32_t define_size = sizeof(define_cmd) + 4;
        uint32_t remap_size = VMW_PPN_SIZE * num_pages + sizeof(remap_cmd) + 4;
        uint32_t *cmd;
        uint32_t *cmd_orig;
        uint32_t i;

        cmd_orig = cmd = vmw_fifo_reserve(dev_priv, define_size + remap_size);
        if (unlikely(cmd == NULL))
                return -ENOMEM;

        define_cmd.gmrId = gmr_id;
        define_cmd.numPages = num_pages;

        remap_cmd.gmrId = gmr_id;
        remap_cmd.flags = (VMW_PPN_SIZE > sizeof(*cmd)) ?
                SVGA_REMAP_GMR2_PPN64 : SVGA_REMAP_GMR2_PPN32;
        remap_cmd.offsetPages = 0;
        remap_cmd.numPages = num_pages;

        *cmd++ = SVGA_CMD_DEFINE_GMR2;
        memcpy(cmd, &define_cmd, sizeof(define_cmd));
        cmd += sizeof(define_cmd) / sizeof(uint32);

        *cmd++ = SVGA_CMD_REMAP_GMR2;
        memcpy(cmd, &remap_cmd, sizeof(remap_cmd));
        cmd += sizeof(remap_cmd) / sizeof(uint32);

        for (i = 0; i < num_pages; ++i) {
                if (VMW_PPN_SIZE > 4)
                        *cmd = page_to_pfn(*pages++);
                else
                        *((uint64_t *)cmd) = page_to_pfn(*pages++);

                cmd += VMW_PPN_SIZE / sizeof(*cmd);
        }

        vmw_fifo_commit(dev_priv, define_size + remap_size);

        return 0;
}

static void vmw_gmr2_unbind(struct vmw_private *dev_priv,
                            int gmr_id)
{
        SVGAFifoCmdDefineGMR2 define_cmd;
        uint32_t define_size = sizeof(define_cmd) + 4;
        uint32_t *cmd;

        cmd = vmw_fifo_reserve(dev_priv, define_size);
        if (unlikely(cmd == NULL)) {
                DRM_ERROR("GMR2 unbind failed.\n");
                return;
        }
        define_cmd.gmrId = gmr_id;
        define_cmd.numPages = 0;

        *cmd++ = SVGA_CMD_DEFINE_GMR2;
        memcpy(cmd, &define_cmd, sizeof(define_cmd));

        vmw_fifo_commit(dev_priv, define_size);
}

/**
 * FIXME: Adjust to the ttm lowmem / highmem storage to minimize
 * the number of used descriptors.
 */

static int vmw_gmr_build_descriptors(struct list_head *desc_pages,
                                     struct page *pages[],
                                     unsigned long num_pages)
{
        struct page *page, *next;
        struct svga_guest_mem_descriptor *page_virtual = NULL;
        struct svga_guest_mem_descriptor *desc_virtual = NULL;
        unsigned int desc_per_page;
        unsigned long prev_pfn;
        unsigned long pfn;
        int ret;

        desc_per_page = PAGE_SIZE /
            sizeof(struct svga_guest_mem_descriptor) - 1;

        while (likely(num_pages != 0)) {
                page = alloc_page(__GFP_HIGHMEM);
                if (unlikely(page == NULL)) {
                        ret = -ENOMEM;
                        goto out_err;
                }

                list_add_tail(&page->lru, desc_pages);

                /*
                 * Point previous page terminating descriptor to this
                 * page before unmapping it.
                 */

                if (likely(page_virtual != NULL)) {
                        desc_virtual->ppn = page_to_pfn(page);
                        kunmap_atomic(page_virtual, KM_USER0);
                }

                page_virtual = kmap_atomic(page, KM_USER0);
                desc_virtual = page_virtual - 1;
                prev_pfn = ~(0UL);

                while (likely(num_pages != 0)) {
                        pfn = page_to_pfn(*pages);

                        if (pfn != prev_pfn + 1) {

                                if (desc_virtual - page_virtual ==
                                    desc_per_page - 1)
                                        break;

                                (++desc_virtual)->ppn = cpu_to_le32(pfn);
                                desc_virtual->num_pages = cpu_to_le32(1);
                        } else {
                                uint32_t tmp =
                                    le32_to_cpu(desc_virtual->num_pages);
                                desc_virtual->num_pages = cpu_to_le32(tmp + 1);
                        }
                        prev_pfn = pfn;
                        --num_pages;
                        ++pages;
                }

                (++desc_virtual)->ppn = cpu_to_le32(0);
                desc_virtual->num_pages = cpu_to_le32(0);
        }

        if (likely(page_virtual != NULL))
                kunmap_atomic(page_virtual, KM_USER0);

        return 0;
out_err:
        list_for_each_entry_safe(page, next, desc_pages, lru) {
                list_del_init(&page->lru);
                __free_page(page);
        }
        return ret;
}

static inline void vmw_gmr_free_descriptors(struct list_head *desc_pages)
{
        struct page *page, *next;

        list_for_each_entry_safe(page, next, desc_pages, lru) {
                list_del_init(&page->lru);
                __free_page(page);
        }
}

static void vmw_gmr_fire_descriptors(struct vmw_private *dev_priv,
                                     int gmr_id, struct list_head *desc_pages)
{
        struct page *page;

        if (unlikely(list_empty(desc_pages)))
                return;

        page = list_entry(desc_pages->next, struct page, lru);

        mutex_lock(&dev_priv->hw_mutex);

        vmw_write(dev_priv, SVGA_REG_GMR_ID, gmr_id);
        wmb();
        vmw_write(dev_priv, SVGA_REG_GMR_DESCRIPTOR, page_to_pfn(page));
        mb();

        mutex_unlock(&dev_priv->hw_mutex);

}

/**
 * FIXME: Adjust to the ttm lowmem / highmem storage to minimize
 * the number of used descriptors.
 */

static unsigned long vmw_gmr_count_descriptors(struct page *pages[],
                                        unsigned long num_pages)
{
        unsigned long prev_pfn = ~(0UL);
        unsigned long pfn;
        unsigned long descriptors = 0;

        while (num_pages--) {
                pfn = page_to_pfn(*pages++);
                if (prev_pfn + 1 != pfn)
                        ++descriptors;
                prev_pfn = pfn;
        }

        return descriptors;
}

int vmw_gmr_bind(struct vmw_private *dev_priv,
                 struct page *pages[],
                 unsigned long num_pages,
                 int gmr_id)
{
        struct list_head desc_pages;
        int ret;

        if (likely(dev_priv->capabilities & SVGA_CAP_GMR2))
                return vmw_gmr2_bind(dev_priv, pages, num_pages, gmr_id);

        if (unlikely(!(dev_priv->capabilities & SVGA_CAP_GMR)))
                return -EINVAL;

        if (vmw_gmr_count_descriptors(pages, num_pages) >
            dev_priv->max_gmr_descriptors)
                return -EINVAL;

        INIT_LIST_HEAD(&desc_pages);

        ret = vmw_gmr_build_descriptors(&desc_pages, pages, num_pages);
        if (unlikely(ret != 0))
                return ret;

        vmw_gmr_fire_descriptors(dev_priv, gmr_id, &desc_pages);
        vmw_gmr_free_descriptors(&desc_pages);

        return 0;
}


void vmw_gmr_unbind(struct vmw_private *dev_priv, int gmr_id)
{
        if (likely(dev_priv->capabilities & SVGA_CAP_GMR2)) {
                vmw_gmr2_unbind(dev_priv, gmr_id);
                return;
        }

        mutex_lock(&dev_priv->hw_mutex);
        vmw_write(dev_priv, SVGA_REG_GMR_ID, gmr_id);
        wmb();
        vmw_write(dev_priv, SVGA_REG_GMR_DESCRIPTOR, 0);
        mb();
        mutex_unlock(&dev_priv->hw_mutex);
}