/**************************************************************************
 * Copyright (c) 2007, Intel Corporation.
 *
 * 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.
 *
 **************************************************************************/
#include <drm/drmP.h>
#include "psb_drv.h"
#include "psb_reg.h"

/*
 * Code for the SGX MMU:
 */

/*
 * clflush on one processor only:
 * clflush should apparently flush the cache line on all processors in an
 * SMP system.
 */

/*
 * kmap atomic:
 * The usage of the slots must be completely encapsulated within a spinlock, and
 * no other functions that may be using the locks for other purposed may be
 * called from within the locked region.
 * Since the slots are per processor, this will guarantee that we are the only
 * user.
 */

/*
 * TODO: Inserting ptes from an interrupt handler:
 * This may be desirable for some SGX functionality where the GPU can fault in
 * needed pages. For that, we need to make an atomic insert_pages function, that
 * may fail.
 * If it fails, the caller need to insert the page using a workqueue function,
 * but on average it should be fast.
 */

struct psb_mmu_driver {
        /* protects driver- and pd structures. Always take in read mode
         * before taking the page table spinlock.
         */
        struct rw_semaphore sem;

        /* protects page tables, directory tables and pt tables.
         * and pt structures.
         */
        spinlock_t lock;

        atomic_t needs_tlbflush;

        uint8_t __iomem *register_map;
        struct psb_mmu_pd *default_pd;
        /*uint32_t bif_ctrl;*/
        int has_clflush;
        int clflush_add;
        unsigned long clflush_mask;

        struct drm_psb_private *dev_priv;
};

struct psb_mmu_pd;

struct psb_mmu_pt {
        struct psb_mmu_pd *pd;
        uint32_t index;
        uint32_t count;
        struct page *p;
        uint32_t *v;
};

struct psb_mmu_pd {
        struct psb_mmu_driver *driver;
        int hw_context;
        struct psb_mmu_pt **tables;
        struct page *p;
        struct page *dummy_pt;
        struct page *dummy_page;
        uint32_t pd_mask;
        uint32_t invalid_pde;
        uint32_t invalid_pte;
};

static inline uint32_t psb_mmu_pt_index(uint32_t offset)
{
        return (offset >> PSB_PTE_SHIFT) & 0x3FF;
}

static inline uint32_t psb_mmu_pd_index(uint32_t offset)
{
        return offset >> PSB_PDE_SHIFT;
}

static inline void psb_clflush(void *addr)
{
        __asm__ __volatile__("clflush (%0)\n" : : "r"(addr) : "memory");
}

static inline void psb_mmu_clflush(struct psb_mmu_driver *driver,
                                   void *addr)
{
        if (!driver->has_clflush)
                return;

        mb();
        psb_clflush(addr);
        mb();
}

static void psb_page_clflush(struct psb_mmu_driver *driver, struct page* page)
{
        uint32_t clflush_add = driver->clflush_add >> PAGE_SHIFT;
        uint32_t clflush_count = PAGE_SIZE / clflush_add;
        int i;
        uint8_t *clf;

        clf = kmap_atomic(page);
        mb();
        for (i = 0; i < clflush_count; ++i) {
                psb_clflush(clf);
                clf += clflush_add;
        }
        mb();
        kunmap_atomic(clf);
}

static void psb_pages_clflush(struct psb_mmu_driver *driver,
                                struct page *page[], unsigned long num_pages)
{
        int i;

        if (!driver->has_clflush)
                return ;

        for (i = 0; i < num_pages; i++)
                psb_page_clflush(driver, *page++);
}

static void psb_mmu_flush_pd_locked(struct psb_mmu_driver *driver,
                                    int force)
{
        atomic_set(&driver->needs_tlbflush, 0);
}

static void psb_mmu_flush_pd(struct psb_mmu_driver *driver, int force)
{
        down_write(&driver->sem);
        psb_mmu_flush_pd_locked(driver, force);
        up_write(&driver->sem);
}

void psb_mmu_flush(struct psb_mmu_driver *driver, int rc_prot)
{
        if (rc_prot)
                down_write(&driver->sem);
        if (rc_prot)
                up_write(&driver->sem);
}

void psb_mmu_set_pd_context(struct psb_mmu_pd *pd, int hw_context)
{
        /*ttm_tt_cache_flush(&pd->p, 1);*/
        psb_pages_clflush(pd->driver, &pd->p, 1);
        down_write(&pd->driver->sem);
        wmb();
        psb_mmu_flush_pd_locked(pd->driver, 1);
        pd->hw_context = hw_context;
        up_write(&pd->driver->sem);

}

static inline unsigned long psb_pd_addr_end(unsigned long addr,
                                            unsigned long end)
{

        addr = (addr + PSB_PDE_MASK + 1) & ~PSB_PDE_MASK;
        return (addr < end) ? addr : end;
}

static inline uint32_t psb_mmu_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;
}

struct psb_mmu_pd *psb_mmu_alloc_pd(struct psb_mmu_driver *driver,
                                    int trap_pagefaults, int invalid_type)
{
        struct psb_mmu_pd *pd = kmalloc(sizeof(*pd), GFP_KERNEL);
        uint32_t *v;
        int i;

        if (!pd)
                return NULL;

        pd->p = alloc_page(GFP_DMA32);
        if (!pd->p)
                goto out_err1;
        pd->dummy_pt = alloc_page(GFP_DMA32);
        if (!pd->dummy_pt)
                goto out_err2;
        pd->dummy_page = alloc_page(GFP_DMA32);
        if (!pd->dummy_page)
                goto out_err3;

        if (!trap_pagefaults) {
                pd->invalid_pde =
                    psb_mmu_mask_pte(page_to_pfn(pd->dummy_pt),
                                     invalid_type);
                pd->invalid_pte =
                    psb_mmu_mask_pte(page_to_pfn(pd->dummy_page),
                                     invalid_type);
        } else {
                pd->invalid_pde = 0;
                pd->invalid_pte = 0;
        }

        v = kmap(pd->dummy_pt);
        for (i = 0; i < (PAGE_SIZE / sizeof(uint32_t)); ++i)
                v[i] = pd->invalid_pte;

        kunmap(pd->dummy_pt);

        v = kmap(pd->p);
        for (i = 0; i < (PAGE_SIZE / sizeof(uint32_t)); ++i)
                v[i] = pd->invalid_pde;

        kunmap(pd->p);

        clear_page(kmap(pd->dummy_page));
        kunmap(pd->dummy_page);

        pd->tables = vmalloc_user(sizeof(struct psb_mmu_pt *) * 1024);
        if (!pd->tables)
                goto out_err4;

        pd->hw_context = -1;
        pd->pd_mask = PSB_PTE_VALID;
        pd->driver = driver;

        return pd;

out_err4:
        __free_page(pd->dummy_page);
out_err3:
        __free_page(pd->dummy_pt);
out_err2:
        __free_page(pd->p);
out_err1:
        kfree(pd);
        return NULL;
}

static void psb_mmu_free_pt(struct psb_mmu_pt *pt)
{
        __free_page(pt->p);
        kfree(pt);
}

void psb_mmu_free_pagedir(struct psb_mmu_pd *pd)
{
        struct psb_mmu_driver *driver = pd->driver;
        struct psb_mmu_pt *pt;
        int i;

        down_write(&driver->sem);
        if (pd->hw_context != -1)
                psb_mmu_flush_pd_locked(driver, 1);

        /* Should take the spinlock here, but we don't need to do that
           since we have the semaphore in write mode. */

        for (i = 0; i < 1024; ++i) {
                pt = pd->tables[i];
                if (pt)
                        psb_mmu_free_pt(pt);
        }

        vfree(pd->tables);
        __free_page(pd->dummy_page);
        __free_page(pd->dummy_pt);
        __free_page(pd->p);
        kfree(pd);
        up_write(&driver->sem);
}

static struct psb_mmu_pt *psb_mmu_alloc_pt(struct psb_mmu_pd *pd)
{
        struct psb_mmu_pt *pt = kmalloc(sizeof(*pt), GFP_KERNEL);
        void *v;
        uint32_t clflush_add = pd->driver->clflush_add >> PAGE_SHIFT;
        uint32_t clflush_count = PAGE_SIZE / clflush_add;
        spinlock_t *lock = &pd->driver->lock;
        uint8_t *clf;
        uint32_t *ptes;
        int i;

        if (!pt)
                return NULL;

        pt->p = alloc_page(GFP_DMA32);
        if (!pt->p) {
                kfree(pt);
                return NULL;
        }

        spin_lock(lock);

        v = kmap_atomic(pt->p);
        clf = (uint8_t *) v;
        ptes = (uint32_t *) v;
        for (i = 0; i < (PAGE_SIZE / sizeof(uint32_t)); ++i)
                *ptes++ = pd->invalid_pte;


        if (pd->driver->has_clflush && pd->hw_context != -1) {
                mb();
                for (i = 0; i < clflush_count; ++i) {
                        psb_clflush(clf);
                        clf += clflush_add;
                }
                mb();
        }

        kunmap_atomic(v);
        spin_unlock(lock);

        pt->count = 0;
        pt->pd = pd;
        pt->index = 0;

        return pt;
}

static struct psb_mmu_pt *psb_mmu_pt_alloc_map_lock(struct psb_mmu_pd *pd,
                                             unsigned long addr)
{
        uint32_t index = psb_mmu_pd_index(addr);
        struct psb_mmu_pt *pt;
        uint32_t *v;
        spinlock_t *lock = &pd->driver->lock;

        spin_lock(lock);
        pt = pd->tables[index];
        while (!pt) {
                spin_unlock(lock);
                pt = psb_mmu_alloc_pt(pd);
                if (!pt)
                        return NULL;
                spin_lock(lock);

                if (pd->tables[index]) {
                        spin_unlock(lock);
                        psb_mmu_free_pt(pt);
                        spin_lock(lock);
                        pt = pd->tables[index];
                        continue;
                }

                v = kmap_atomic(pd->p);
                pd->tables[index] = pt;
                v[index] = (page_to_pfn(pt->p) << 12) | pd->pd_mask;
                pt->index = index;
                kunmap_atomic((void *) v);

                if (pd->hw_context != -1) {
                        psb_mmu_clflush(pd->driver, (void *) &v[index]);
                        atomic_set(&pd->driver->needs_tlbflush, 1);
                }
        }
        pt->v = kmap_atomic(pt->p);
        return pt;
}

static struct psb_mmu_pt *psb_mmu_pt_map_lock(struct psb_mmu_pd *pd,
                                              unsigned long addr)
{
        uint32_t index = psb_mmu_pd_index(addr);
        struct psb_mmu_pt *pt;
        spinlock_t *lock = &pd->driver->lock;

        spin_lock(lock);
        pt = pd->tables[index];
        if (!pt) {
                spin_unlock(lock);
                return NULL;
        }
        pt->v = kmap_atomic(pt->p);
        return pt;
}

static void psb_mmu_pt_unmap_unlock(struct psb_mmu_pt *pt)
{
        struct psb_mmu_pd *pd = pt->pd;
        uint32_t *v;

        kunmap_atomic(pt->v);
        if (pt->count == 0) {
                v = kmap_atomic(pd->p);
                v[pt->index] = pd->invalid_pde;
                pd->tables[pt->index] = NULL;

                if (pd->hw_context != -1) {
                        psb_mmu_clflush(pd->driver,
                                        (void *) &v[pt->index]);
                        atomic_set(&pd->driver->needs_tlbflush, 1);
                }
                kunmap_atomic(pt->v);
                spin_unlock(&pd->driver->lock);
                psb_mmu_free_pt(pt);
                return;
        }
        spin_unlock(&pd->driver->lock);
}

static inline void psb_mmu_set_pte(struct psb_mmu_pt *pt,
                                   unsigned long addr, uint32_t pte)
{
        pt->v[psb_mmu_pt_index(addr)] = pte;
}

static inline void psb_mmu_invalidate_pte(struct psb_mmu_pt *pt,
                                          unsigned long addr)
{
        pt->v[psb_mmu_pt_index(addr)] = pt->pd->invalid_pte;
}


void psb_mmu_mirror_gtt(struct psb_mmu_pd *pd,
                        uint32_t mmu_offset, uint32_t gtt_start,
                        uint32_t gtt_pages)
{
        uint32_t *v;
        uint32_t start = psb_mmu_pd_index(mmu_offset);
        struct psb_mmu_driver *driver = pd->driver;
        int num_pages = gtt_pages;

        down_read(&driver->sem);
        spin_lock(&driver->lock);

        v = kmap_atomic(pd->p);
        v += start;

        while (gtt_pages--) {
                *v++ = gtt_start | pd->pd_mask;
                gtt_start += PAGE_SIZE;
        }

        /*ttm_tt_cache_flush(&pd->p, num_pages);*/
        psb_pages_clflush(pd->driver, &pd->p, num_pages);
        kunmap_atomic(v);
        spin_unlock(&driver->lock);

        if (pd->hw_context != -1)
                atomic_set(&pd->driver->needs_tlbflush, 1);

        up_read(&pd->driver->sem);
        psb_mmu_flush_pd(pd->driver, 0);
}

struct psb_mmu_pd *psb_mmu_get_default_pd(struct psb_mmu_driver *driver)
{
        struct psb_mmu_pd *pd;

        /* down_read(&driver->sem); */
        pd = driver->default_pd;
        /* up_read(&driver->sem); */

        return pd;
}

void psb_mmu_driver_takedown(struct psb_mmu_driver *driver)
{
        psb_mmu_free_pagedir(driver->default_pd);
        kfree(driver);
}

struct psb_mmu_driver *psb_mmu_driver_init(uint8_t __iomem * registers,
                                        int trap_pagefaults,
                                        int invalid_type,
                                        struct drm_psb_private *dev_priv)
{
        struct psb_mmu_driver *driver;

        driver = kmalloc(sizeof(*driver), GFP_KERNEL);

        if (!driver)
                return NULL;
        driver->dev_priv = dev_priv;

        driver->default_pd = psb_mmu_alloc_pd(driver, trap_pagefaults,
                                              invalid_type);
        if (!driver->default_pd)
                goto out_err1;

        spin_lock_init(&driver->lock);
        init_rwsem(&driver->sem);
        down_write(&driver->sem);
        driver->register_map = registers;
        atomic_set(&driver->needs_tlbflush, 1);

        driver->has_clflush = 0;

        if (boot_cpu_has(X86_FEATURE_CLFLSH)) {
                uint32_t tfms, misc, cap0, cap4, clflush_size;

                /*
                 * clflush size is determined at kernel setup for x86_64
                 *  but not for i386. We have to do it here.
                 */

                cpuid(0x00000001, &tfms, &misc, &cap0, &cap4);
                clflush_size = ((misc >> 8) & 0xff) * 8;
                driver->has_clflush = 1;
                driver->clflush_add =
                    PAGE_SIZE * clflush_size / sizeof(uint32_t);
                driver->clflush_mask = driver->clflush_add - 1;
                driver->clflush_mask = ~driver->clflush_mask;
        }

        up_write(&driver->sem);
        return driver;

out_err1:
        kfree(driver);
        return NULL;
}

static void psb_mmu_flush_ptes(struct psb_mmu_pd *pd,
                               unsigned long address, uint32_t num_pages,
                               uint32_t desired_tile_stride,
                               uint32_t hw_tile_stride)
{
        struct psb_mmu_pt *pt;
        uint32_t rows = 1;
        uint32_t i;
        unsigned long addr;
        unsigned long end;
        unsigned long next;
        unsigned long add;
        unsigned long row_add;
        unsigned long clflush_add = pd->driver->clflush_add;
        unsigned long clflush_mask = pd->driver->clflush_mask;

        if (!pd->driver->has_clflush) {
                /*ttm_tt_cache_flush(&pd->p, num_pages);*/
                psb_pages_clflush(pd->driver, &pd->p, num_pages);
                return;
        }

        if (hw_tile_stride)
                rows = num_pages / desired_tile_stride;
        else
                desired_tile_stride = num_pages;

        add = desired_tile_stride << PAGE_SHIFT;
        row_add = hw_tile_stride << PAGE_SHIFT;
        mb();
        for (i = 0; i < rows; ++i) {

                addr = address;
                end = addr + add;

                do {
                        next = psb_pd_addr_end(addr, end);
                        pt = psb_mmu_pt_map_lock(pd, addr);
                        if (!pt)
                                continue;
                        do {
                                psb_clflush(&pt->v
                                            [psb_mmu_pt_index(addr)]);
                        } while (addr +=
                                 clflush_add,
                                 (addr & clflush_mask) < next);

                        psb_mmu_pt_unmap_unlock(pt);
                } while (addr = next, next != end);
                address += row_add;
        }
        mb();
}

void psb_mmu_remove_pfn_sequence(struct psb_mmu_pd *pd,
                                 unsigned long address, uint32_t num_pages)
{
        struct psb_mmu_pt *pt;
        unsigned long addr;
        unsigned long end;
        unsigned long next;
        unsigned long f_address = address;

        down_read(&pd->driver->sem);

        addr = address;
        end = addr + (num_pages << PAGE_SHIFT);

        do {
                next = psb_pd_addr_end(addr, end);
                pt = psb_mmu_pt_alloc_map_lock(pd, addr);
                if (!pt)
                        goto out;
                do {
                        psb_mmu_invalidate_pte(pt, addr);
                        --pt->count;
                } while (addr += PAGE_SIZE, addr < next);
                psb_mmu_pt_unmap_unlock(pt);

        } while (addr = next, next != end);

out:
        if (pd->hw_context != -1)
                psb_mmu_flush_ptes(pd, f_address, num_pages, 1, 1);

        up_read(&pd->driver->sem);

        if (pd->hw_context != -1)
                psb_mmu_flush(pd->driver, 0);

        return;
}

void psb_mmu_remove_pages(struct psb_mmu_pd *pd, unsigned long address,
                          uint32_t num_pages, uint32_t desired_tile_stride,
                          uint32_t hw_tile_stride)
{
        struct psb_mmu_pt *pt;
        uint32_t rows = 1;
        uint32_t i;
        unsigned long addr;
        unsigned long end;
        unsigned long next;
        unsigned long add;
        unsigned long row_add;
        unsigned long f_address = address;

        if (hw_tile_stride)
                rows = num_pages / desired_tile_stride;
        else
                desired_tile_stride = num_pages;

        add = desired_tile_stride << PAGE_SHIFT;
        row_add = hw_tile_stride << PAGE_SHIFT;

        /* down_read(&pd->driver->sem); */

        /* Make sure we only need to flush this processor's cache */

        for (i = 0; i < rows; ++i) {

                addr = address;
                end = addr + add;

                do {
                        next = psb_pd_addr_end(addr, end);
                        pt = psb_mmu_pt_map_lock(pd, addr);
                        if (!pt)
                                continue;
                        do {
                                psb_mmu_invalidate_pte(pt, addr);
                                --pt->count;

                        } while (addr += PAGE_SIZE, addr < next);
                        psb_mmu_pt_unmap_unlock(pt);

                } while (addr = next, next != end);
                address += row_add;
        }
        if (pd->hw_context != -1)
                psb_mmu_flush_ptes(pd, f_address, num_pages,
                                   desired_tile_stride, hw_tile_stride);

        /* up_read(&pd->driver->sem); */

        if (pd->hw_context != -1)
                psb_mmu_flush(pd->driver, 0);
}

int psb_mmu_insert_pfn_sequence(struct psb_mmu_pd *pd, uint32_t start_pfn,
                                unsigned long address, uint32_t num_pages,
                                int type)
{
        struct psb_mmu_pt *pt;
        uint32_t pte;
        unsigned long addr;
        unsigned long end;
        unsigned long next;
        unsigned long f_address = address;
        int ret = 0;

        down_read(&pd->driver->sem);

        addr = address;
        end = addr + (num_pages << PAGE_SHIFT);

        do {
                next = psb_pd_addr_end(addr, end);
                pt = psb_mmu_pt_alloc_map_lock(pd, addr);
                if (!pt) {
                        ret = -ENOMEM;
                        goto out;
                }
                do {
                        pte = psb_mmu_mask_pte(start_pfn++, type);
                        psb_mmu_set_pte(pt, addr, pte);
                        pt->count++;
                } while (addr += PAGE_SIZE, addr < next);
                psb_mmu_pt_unmap_unlock(pt);

        } while (addr = next, next != end);

out:
        if (pd->hw_context != -1)
                psb_mmu_flush_ptes(pd, f_address, num_pages, 1, 1);

        up_read(&pd->driver->sem);

        if (pd->hw_context != -1)
                psb_mmu_flush(pd->driver, 1);

        return ret;
}

int psb_mmu_insert_pages(struct psb_mmu_pd *pd, struct page **pages,
                         unsigned long address, uint32_t num_pages,
                         uint32_t desired_tile_stride,
                         uint32_t hw_tile_stride, int type)
{
        struct psb_mmu_pt *pt;
        uint32_t rows = 1;
        uint32_t i;
        uint32_t pte;
        unsigned long addr;
        unsigned long end;
        unsigned long next;
        unsigned long add;
        unsigned long row_add;
        unsigned long f_address = address;
        int ret = 0;

        if (hw_tile_stride) {
                if (num_pages % desired_tile_stride != 0)
                        return -EINVAL;
                rows = num_pages / desired_tile_stride;
        } else {
                desired_tile_stride = num_pages;
        }

        add = desired_tile_stride << PAGE_SHIFT;
        row_add = hw_tile_stride << PAGE_SHIFT;

        down_read(&pd->driver->sem);

        for (i = 0; i < rows; ++i) {

                addr = address;
                end = addr + add;

                do {
                        next = psb_pd_addr_end(addr, end);
                        pt = psb_mmu_pt_alloc_map_lock(pd, addr);
                        if (!pt) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        do {
                                pte =
                                    psb_mmu_mask_pte(page_to_pfn(*pages++),
                                                     type);
                                psb_mmu_set_pte(pt, addr, pte);
                                pt->count++;
                        } while (addr += PAGE_SIZE, addr < next);
                        psb_mmu_pt_unmap_unlock(pt);

                } while (addr = next, next != end);

                address += row_add;
        }
out:
        if (pd->hw_context != -1)
                psb_mmu_flush_ptes(pd, f_address, num_pages,
                                   desired_tile_stride, hw_tile_stride);

        up_read(&pd->driver->sem);

        if (pd->hw_context != -1)
                psb_mmu_flush(pd->driver, 1);

        return ret;
}

int psb_mmu_virtual_to_pfn(struct psb_mmu_pd *pd, uint32_t virtual,
                           unsigned long *pfn)
{
        int ret;
        struct psb_mmu_pt *pt;
        uint32_t tmp;
        spinlock_t *lock = &pd->driver->lock;

        down_read(&pd->driver->sem);
        pt = psb_mmu_pt_map_lock(pd, virtual);
        if (!pt) {
                uint32_t *v;

                spin_lock(lock);
                v = kmap_atomic(pd->p);
                tmp = v[psb_mmu_pd_index(virtual)];
                kunmap_atomic(v);
                spin_unlock(lock);

                if (tmp != pd->invalid_pde || !(tmp & PSB_PTE_VALID) ||
                    !(pd->invalid_pte & PSB_PTE_VALID)) {
                        ret = -EINVAL;
                        goto out;
                }
                ret = 0;
                *pfn = pd->invalid_pte >> PAGE_SHIFT;
                goto out;
        }
        tmp = pt->v[psb_mmu_pt_index(virtual)];
        if (!(tmp & PSB_PTE_VALID)) {
                ret = -EINVAL;
        } else {
                ret = 0;
                *pfn = tmp >> PAGE_SHIFT;
        }
        psb_mmu_pt_unmap_unlock(pt);
out:
        up_read(&pd->driver->sem);
        return ret;
}