/*
 * VRAM manager for OMAP
 *
 * Copyright (C) 2009 Nokia Corporation
 * Author: Tomi Valkeinen <tomi.valkeinen@nokia.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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.,
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

/*#define DEBUG*/

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/memblock.h>
#include <linux/completion.h>
#include <linux/debugfs.h>
#include <linux/jiffies.h>
#include <linux/module.h>

#include <asm/setup.h>

#include <plat/sram.h>
#include <plat/vram.h>
#include <plat/dma.h>

#ifdef DEBUG
#define DBG(format, ...) pr_debug("VRAM: " format, ## __VA_ARGS__)
#else
#define DBG(format, ...)
#endif

#define OMAP2_SRAM_START                0x40200000
/* Maximum size, in reality this is smaller if SRAM is partially locked. */
#define OMAP2_SRAM_SIZE                 0xa0000         /* 640k */

/* postponed regions are used to temporarily store region information at boot
 * time when we cannot yet allocate the region list */
#define MAX_POSTPONED_REGIONS 10

static bool vram_initialized;
static int postponed_cnt;
static struct {
        unsigned long paddr;
        size_t size;
} postponed_regions[MAX_POSTPONED_REGIONS];

struct vram_alloc {
        struct list_head list;
        unsigned long paddr;
        unsigned pages;
};

struct vram_region {
        struct list_head list;
        struct list_head alloc_list;
        unsigned long paddr;
        unsigned pages;
};

static DEFINE_MUTEX(region_mutex);
static LIST_HEAD(region_list);

static inline int region_mem_type(unsigned long paddr)
{
        if (paddr >= OMAP2_SRAM_START &&
            paddr < OMAP2_SRAM_START + OMAP2_SRAM_SIZE)
                return OMAP_VRAM_MEMTYPE_SRAM;
        else
                return OMAP_VRAM_MEMTYPE_SDRAM;
}

static struct vram_region *omap_vram_create_region(unsigned long paddr,
                unsigned pages)
{
        struct vram_region *rm;

        rm = kzalloc(sizeof(*rm), GFP_KERNEL);

        if (rm) {
                INIT_LIST_HEAD(&rm->alloc_list);
                rm->paddr = paddr;
                rm->pages = pages;
        }

        return rm;
}

#if 0
static void omap_vram_free_region(struct vram_region *vr)
{
        list_del(&vr->list);
        kfree(vr);
}
#endif

static struct vram_alloc *omap_vram_create_allocation(struct vram_region *vr,
                unsigned long paddr, unsigned pages)
{
        struct vram_alloc *va;
        struct vram_alloc *new;

        new = kzalloc(sizeof(*va), GFP_KERNEL);

        if (!new)
                return NULL;

        new->paddr = paddr;
        new->pages = pages;

        list_for_each_entry(va, &vr->alloc_list, list) {
                if (va->paddr > new->paddr)
                        break;
        }

        list_add_tail(&new->list, &va->list);

        return new;
}

static void omap_vram_free_allocation(struct vram_alloc *va)
{
        list_del(&va->list);
        kfree(va);
}

int omap_vram_add_region(unsigned long paddr, size_t size)
{
        struct vram_region *rm;
        unsigned pages;

        if (vram_initialized) {
                DBG("adding region paddr %08lx size %d\n",
                                paddr, size);

                size &= PAGE_MASK;
                pages = size >> PAGE_SHIFT;

                rm = omap_vram_create_region(paddr, pages);
                if (rm == NULL)
                        return -ENOMEM;

                list_add(&rm->list, &region_list);
        } else {
                if (postponed_cnt == MAX_POSTPONED_REGIONS)
                        return -ENOMEM;

                postponed_regions[postponed_cnt].paddr = paddr;
                postponed_regions[postponed_cnt].size = size;

                ++postponed_cnt;
        }
        return 0;
}

int omap_vram_free(unsigned long paddr, size_t size)
{
        struct vram_region *rm;
        struct vram_alloc *alloc;
        unsigned start, end;

        DBG("free mem paddr %08lx size %d\n", paddr, size);

        size = PAGE_ALIGN(size);

        mutex_lock(&region_mutex);

        list_for_each_entry(rm, &region_list, list) {
                list_for_each_entry(alloc, &rm->alloc_list, list) {
                        start = alloc->paddr;
                        end = alloc->paddr + (alloc->pages >> PAGE_SHIFT);

                        if (start >= paddr && end < paddr + size)
                                goto found;
                }
        }

        mutex_unlock(&region_mutex);
        return -EINVAL;

found:
        omap_vram_free_allocation(alloc);

        mutex_unlock(&region_mutex);
        return 0;
}
EXPORT_SYMBOL(omap_vram_free);

static int _omap_vram_reserve(unsigned long paddr, unsigned pages)
{
        struct vram_region *rm;
        struct vram_alloc *alloc;
        size_t size;

        size = pages << PAGE_SHIFT;

        list_for_each_entry(rm, &region_list, list) {
                unsigned long start, end;

                DBG("checking region %lx %d\n", rm->paddr, rm->pages);

                if (region_mem_type(rm->paddr) != region_mem_type(paddr))
                        continue;

                start = rm->paddr;
                end = start + (rm->pages << PAGE_SHIFT) - 1;
                if (start > paddr || end < paddr + size - 1)
                        continue;

                DBG("block ok, checking allocs\n");

                list_for_each_entry(alloc, &rm->alloc_list, list) {
                        end = alloc->paddr - 1;

                        if (start <= paddr && end >= paddr + size - 1)
                                goto found;

                        start = alloc->paddr + (alloc->pages << PAGE_SHIFT);
                }

                end = rm->paddr + (rm->pages << PAGE_SHIFT) - 1;

                if (!(start <= paddr && end >= paddr + size - 1))
                        continue;
found:
                DBG("found area start %lx, end %lx\n", start, end);

                if (omap_vram_create_allocation(rm, paddr, pages) == NULL)
                        return -ENOMEM;

                return 0;
        }

        return -ENOMEM;
}

int omap_vram_reserve(unsigned long paddr, size_t size)
{
        unsigned pages;
        int r;

        DBG("reserve mem paddr %08lx size %d\n", paddr, size);

        size = PAGE_ALIGN(size);
        pages = size >> PAGE_SHIFT;

        mutex_lock(&region_mutex);

        r = _omap_vram_reserve(paddr, pages);

        mutex_unlock(&region_mutex);

        return r;
}
EXPORT_SYMBOL(omap_vram_reserve);

static void _omap_vram_dma_cb(int lch, u16 ch_status, void *data)
{
        struct completion *compl = data;
        complete(compl);
}

static int _omap_vram_clear(u32 paddr, unsigned pages)
{
        struct completion compl;
        unsigned elem_count;
        unsigned frame_count;
        int r;
        int lch;

        init_completion(&compl);

        r = omap_request_dma(OMAP_DMA_NO_DEVICE, "VRAM DMA",
                        _omap_vram_dma_cb,
                        &compl, &lch);
        if (r) {
                pr_err("VRAM: request_dma failed for memory clear\n");
                return -EBUSY;
        }

        elem_count = pages * PAGE_SIZE / 4;
        frame_count = 1;

        omap_set_dma_transfer_params(lch, OMAP_DMA_DATA_TYPE_S32,
                        elem_count, frame_count,
                        OMAP_DMA_SYNC_ELEMENT,
                        0, 0);

        omap_set_dma_dest_params(lch, 0, OMAP_DMA_AMODE_POST_INC,
                        paddr, 0, 0);

        omap_set_dma_color_mode(lch, OMAP_DMA_CONSTANT_FILL, 0x000000);

        omap_start_dma(lch);

        if (wait_for_completion_timeout(&compl, msecs_to_jiffies(1000)) == 0) {
                omap_stop_dma(lch);
                pr_err("VRAM: dma timeout while clearing memory\n");
                r = -EIO;
                goto err;
        }

        r = 0;
err:
        omap_free_dma(lch);

        return r;
}

static int _omap_vram_alloc(int mtype, unsigned pages, unsigned long *paddr)
{
        struct vram_region *rm;
        struct vram_alloc *alloc;

        list_for_each_entry(rm, &region_list, list) {
                unsigned long start, end;

                DBG("checking region %lx %d\n", rm->paddr, rm->pages);

                if (region_mem_type(rm->paddr) != mtype)
                        continue;

                start = rm->paddr;

                list_for_each_entry(alloc, &rm->alloc_list, list) {
                        end = alloc->paddr;

                        if (end - start >= pages << PAGE_SHIFT)
                                goto found;

                        start = alloc->paddr + (alloc->pages << PAGE_SHIFT);
                }

                end = rm->paddr + (rm->pages << PAGE_SHIFT);
found:
                if (end - start < pages << PAGE_SHIFT)
                        continue;

                DBG("found %lx, end %lx\n", start, end);

                alloc = omap_vram_create_allocation(rm, start, pages);
                if (alloc == NULL)
                        return -ENOMEM;

                *paddr = start;

                _omap_vram_clear(start, pages);

                return 0;
        }

        return -ENOMEM;
}

int omap_vram_alloc(int mtype, size_t size, unsigned long *paddr)
{
        unsigned pages;
        int r;

        BUG_ON(mtype > OMAP_VRAM_MEMTYPE_MAX || !size);

        DBG("alloc mem type %d size %d\n", mtype, size);

        size = PAGE_ALIGN(size);
        pages = size >> PAGE_SHIFT;

        mutex_lock(&region_mutex);

        r = _omap_vram_alloc(mtype, pages, paddr);

        mutex_unlock(&region_mutex);

        return r;
}
EXPORT_SYMBOL(omap_vram_alloc);

void omap_vram_get_info(unsigned long *vram,
                unsigned long *free_vram,
                unsigned long *largest_free_block)
{
        struct vram_region *vr;
        struct vram_alloc *va;

        *vram = 0;
        *free_vram = 0;
        *largest_free_block = 0;

        mutex_lock(&region_mutex);

        list_for_each_entry(vr, &region_list, list) {
                unsigned free;
                unsigned long pa;

                pa = vr->paddr;
                *vram += vr->pages << PAGE_SHIFT;

                list_for_each_entry(va, &vr->alloc_list, list) {
                        free = va->paddr - pa;
                        *free_vram += free;
                        if (free > *largest_free_block)
                                *largest_free_block = free;
                        pa = va->paddr + (va->pages << PAGE_SHIFT);
                }

                free = vr->paddr + (vr->pages << PAGE_SHIFT) - pa;
                *free_vram += free;
                if (free > *largest_free_block)
                        *largest_free_block = free;
        }

        mutex_unlock(&region_mutex);
}
EXPORT_SYMBOL(omap_vram_get_info);

#if defined(CONFIG_DEBUG_FS)
static int vram_debug_show(struct seq_file *s, void *unused)
{
        struct vram_region *vr;
        struct vram_alloc *va;
        unsigned size;

        mutex_lock(&region_mutex);

        list_for_each_entry(vr, &region_list, list) {
                size = vr->pages << PAGE_SHIFT;
                seq_printf(s, "%08lx-%08lx (%d bytes)\n",
                                vr->paddr, vr->paddr + size - 1,
                                size);

                list_for_each_entry(va, &vr->alloc_list, list) {
                        size = va->pages << PAGE_SHIFT;
                        seq_printf(s, "    %08lx-%08lx (%d bytes)\n",
                                        va->paddr, va->paddr + size - 1,
                                        size);
                }
        }

        mutex_unlock(&region_mutex);

        return 0;
}

static int vram_debug_open(struct inode *inode, struct file *file)
{
        return single_open(file, vram_debug_show, inode->i_private);
}

static const struct file_operations vram_debug_fops = {
        .open           = vram_debug_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static int __init omap_vram_create_debugfs(void)
{
        struct dentry *d;

        d = debugfs_create_file("vram", S_IRUGO, NULL,
                        NULL, &vram_debug_fops);
        if (IS_ERR(d))
                return PTR_ERR(d);

        return 0;
}
#endif

static __init int omap_vram_init(void)
{
        int i;

        vram_initialized = 1;

        for (i = 0; i < postponed_cnt; i++)
                omap_vram_add_region(postponed_regions[i].paddr,
                                postponed_regions[i].size);

#ifdef CONFIG_DEBUG_FS
        if (omap_vram_create_debugfs())
                pr_err("VRAM: Failed to create debugfs file\n");
#endif

        return 0;
}

arch_initcall(omap_vram_init);

/* boottime vram alloc stuff */

/* set from board file */
static u32 omap_vram_sram_start __initdata;
static u32 omap_vram_sram_size __initdata;

/* set from board file */
static u32 omap_vram_sdram_start __initdata;
static u32 omap_vram_sdram_size __initdata;

/* set from kernel cmdline */
static u32 omap_vram_def_sdram_size __initdata;
static u32 omap_vram_def_sdram_start __initdata;

static int __init omap_vram_early_vram(char *p)
{
        omap_vram_def_sdram_size = memparse(p, &p);
        if (*p == ',')
                omap_vram_def_sdram_start = simple_strtoul(p + 1, &p, 16);
        return 0;
}
early_param("vram", omap_vram_early_vram);

/*
 * Called from map_io. We need to call to this early enough so that we
 * can reserve the fixed SDRAM regions before VM could get hold of them.
 */
void __init omap_vram_reserve_sdram_memblock(void)
{
        u32 paddr;
        u32 size = 0;

        /* cmdline arg overrides the board file definition */
        if (omap_vram_def_sdram_size) {
                size = omap_vram_def_sdram_size;
                paddr = omap_vram_def_sdram_start;
        }

        if (!size) {
                size = omap_vram_sdram_size;
                paddr = omap_vram_sdram_start;
        }

#ifdef CONFIG_OMAP2_VRAM_SIZE
        if (!size) {
                size = CONFIG_OMAP2_VRAM_SIZE * 1024 * 1024;
                paddr = 0;
        }
#endif

        if (!size)
                return;

        size = ALIGN(size, SZ_2M);

        if (paddr) {
                if (paddr & ~PAGE_MASK) {
                        pr_err("VRAM start address 0x%08x not page aligned\n",
                                        paddr);
                        return;
                }

                if (!memblock_is_region_memory(paddr, size)) {
                        pr_err("Illegal SDRAM region 0x%08x..0x%08x for VRAM\n",
                                        paddr, paddr + size - 1);
                        return;
                }

                if (memblock_is_region_reserved(paddr, size)) {
                        pr_err("FB: failed to reserve VRAM - busy\n");
                        return;
                }

                if (memblock_reserve(paddr, size) < 0) {
                        pr_err("FB: failed to reserve VRAM - no memory\n");
                        return;
                }
        } else {
                paddr = memblock_alloc(size, SZ_2M);
        }

        memblock_free(paddr, size);
        memblock_remove(paddr, size);

        omap_vram_add_region(paddr, size);

        pr_info("Reserving %u bytes SDRAM for VRAM\n", size);
}

/*
 * Called at sram init time, before anything is pushed to the SRAM stack.
 * Because of the stack scheme, we will allocate everything from the
 * start of the lowest address region to the end of SRAM. This will also
 * include padding for page alignment and possible holes between regions.
 *
 * As opposed to the SDRAM case, we'll also do any dynamic allocations at
 * this point, since the driver built as a module would have problem with
 * freeing / reallocating the regions.
 */
unsigned long __init omap_vram_reserve_sram(unsigned long sram_pstart,
                                  unsigned long sram_vstart,
                                  unsigned long sram_size,
                                  unsigned long pstart_avail,
                                  unsigned long size_avail)
{
        unsigned long                   pend_avail;
        unsigned long                   reserved;
        u32 paddr;
        u32 size;

        paddr = omap_vram_sram_start;
        size = omap_vram_sram_size;

        if (!size)
                return 0;

        reserved = 0;
        pend_avail = pstart_avail + size_avail;

        if (!paddr) {
                /* Dynamic allocation */
                if ((size_avail & PAGE_MASK) < size) {
                        pr_err("Not enough SRAM for VRAM\n");
                        return 0;
                }
                size_avail = (size_avail - size) & PAGE_MASK;
                paddr = pstart_avail + size_avail;
        }

        if (paddr < sram_pstart ||
                        paddr + size > sram_pstart + sram_size) {
                pr_err("Illegal SRAM region for VRAM\n");
                return 0;
        }

        /* Reserve everything above the start of the region. */
        if (pend_avail - paddr > reserved)
                reserved = pend_avail - paddr;
        size_avail = pend_avail - reserved - pstart_avail;

        omap_vram_add_region(paddr, size);

        if (reserved)
                pr_info("Reserving %lu bytes SRAM for VRAM\n", reserved);

        return reserved;
}

void __init omap_vram_set_sdram_vram(u32 size, u32 start)
{
        omap_vram_sdram_start = start;
        omap_vram_sdram_size = size;
}

void __init omap_vram_set_sram_vram(u32 size, u32 start)
{
        omap_vram_sram_start = start;
        omap_vram_sram_size = size;
}