/*
 * DMM IOMMU driver support functions for TI OMAP processors.
 *
 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
 * Author: Rob Clark <rob@ti.com>
 *         Andy Gross <andy.gross@ti.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/platform_device.h> /* platform_device() */
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>

#include "omap_dmm_tiler.h"
#include "omap_dmm_priv.h"

#define DMM_DRIVER_NAME "dmm"

/* mappings for associating views to luts */
static struct tcm *containers[TILFMT_NFORMATS];
static struct dmm *omap_dmm;

#if defined(CONFIG_OF)
static const struct of_device_id dmm_of_match[];
#endif

/* global spinlock for protecting lists */
static DEFINE_SPINLOCK(list_lock);

/* Geometry table */
#define GEOM(xshift, yshift, bytes_per_pixel) { \
                .x_shft = (xshift), \
                .y_shft = (yshift), \
                .cpp    = (bytes_per_pixel), \
                .slot_w = 1 << (SLOT_WIDTH_BITS - (xshift)), \
                .slot_h = 1 << (SLOT_HEIGHT_BITS - (yshift)), \
        }

static const struct {
        u32 x_shft;     /* unused X-bits (as part of bpp) */
        u32 y_shft;     /* unused Y-bits (as part of bpp) */
        u32 cpp;                /* bytes/chars per pixel */
        u32 slot_w;     /* width of each slot (in pixels) */
        u32 slot_h;     /* height of each slot (in pixels) */
} geom[TILFMT_NFORMATS] = {
        [TILFMT_8BIT]  = GEOM(0, 0, 1),
        [TILFMT_16BIT] = GEOM(0, 1, 2),
        [TILFMT_32BIT] = GEOM(1, 1, 4),
        [TILFMT_PAGE]  = GEOM(SLOT_WIDTH_BITS, SLOT_HEIGHT_BITS, 1),
};


/* lookup table for registers w/ per-engine instances */
static const u32 reg[][4] = {
        [PAT_STATUS] = {DMM_PAT_STATUS__0, DMM_PAT_STATUS__1,
                        DMM_PAT_STATUS__2, DMM_PAT_STATUS__3},
        [PAT_DESCR]  = {DMM_PAT_DESCR__0, DMM_PAT_DESCR__1,
                        DMM_PAT_DESCR__2, DMM_PAT_DESCR__3},
};

static int dmm_dma_copy(struct dmm *dmm, dma_addr_t src, dma_addr_t dst)
{
        struct dma_async_tx_descriptor *tx;
        enum dma_status status;
        dma_cookie_t cookie;

        tx = dmaengine_prep_dma_memcpy(dmm->wa_dma_chan, dst, src, 4, 0);
        if (!tx) {
                dev_err(dmm->dev, "Failed to prepare DMA memcpy\n");
                return -EIO;
        }

        cookie = tx->tx_submit(tx);
        if (dma_submit_error(cookie)) {
                dev_err(dmm->dev, "Failed to do DMA tx_submit\n");
                return -EIO;
        }

        status = dma_sync_wait(dmm->wa_dma_chan, cookie);
        if (status != DMA_COMPLETE)
                dev_err(dmm->dev, "i878 wa DMA copy failure\n");

        dmaengine_terminate_all(dmm->wa_dma_chan);
        return 0;
}

static u32 dmm_read_wa(struct dmm *dmm, u32 reg)
{
        dma_addr_t src, dst;
        int r;

        src = dmm->phys_base + reg;
        dst = dmm->wa_dma_handle;

        r = dmm_dma_copy(dmm, src, dst);
        if (r) {
                dev_err(dmm->dev, "sDMA read transfer timeout\n");
                return readl(dmm->base + reg);
        }

        /*
         * As per i878 workaround, the DMA is used to access the DMM registers.
         * Make sure that the readl is not moved by the compiler or the CPU
         * earlier than the DMA finished writing the value to memory.
         */
        rmb();
        return readl(dmm->wa_dma_data);
}

static void dmm_write_wa(struct dmm *dmm, u32 val, u32 reg)
{
        dma_addr_t src, dst;
        int r;

        writel(val, dmm->wa_dma_data);
        /*
         * As per i878 workaround, the DMA is used to access the DMM registers.
         * Make sure that the writel is not moved by the compiler or the CPU, so
         * the data will be in place before we start the DMA to do the actual
         * register write.
         */
        wmb();

        src = dmm->wa_dma_handle;
        dst = dmm->phys_base + reg;

        r = dmm_dma_copy(dmm, src, dst);
        if (r) {
                dev_err(dmm->dev, "sDMA write transfer timeout\n");
                writel(val, dmm->base + reg);
        }
}

static u32 dmm_read(struct dmm *dmm, u32 reg)
{
        if (dmm->dmm_workaround) {
                u32 v;
                unsigned long flags;

                spin_lock_irqsave(&dmm->wa_lock, flags);
                v = dmm_read_wa(dmm, reg);
                spin_unlock_irqrestore(&dmm->wa_lock, flags);

                return v;
        } else {
                return readl(dmm->base + reg);
        }
}

static void dmm_write(struct dmm *dmm, u32 val, u32 reg)
{
        if (dmm->dmm_workaround) {
                unsigned long flags;

                spin_lock_irqsave(&dmm->wa_lock, flags);
                dmm_write_wa(dmm, val, reg);
                spin_unlock_irqrestore(&dmm->wa_lock, flags);
        } else {
                writel(val, dmm->base + reg);
        }
}

static int dmm_workaround_init(struct dmm *dmm)
{
        dma_cap_mask_t mask;

        spin_lock_init(&dmm->wa_lock);

        dmm->wa_dma_data = dma_alloc_coherent(dmm->dev,  sizeof(u32),
                                              &dmm->wa_dma_handle, GFP_KERNEL);
        if (!dmm->wa_dma_data)
                return -ENOMEM;

        dma_cap_zero(mask);
        dma_cap_set(DMA_MEMCPY, mask);

        dmm->wa_dma_chan = dma_request_channel(mask, NULL, NULL);
        if (!dmm->wa_dma_chan) {
                dma_free_coherent(dmm->dev, 4, dmm->wa_dma_data, dmm->wa_dma_handle);
                return -ENODEV;
        }

        return 0;
}

static void dmm_workaround_uninit(struct dmm *dmm)
{
        dma_release_channel(dmm->wa_dma_chan);

        dma_free_coherent(dmm->dev, 4, dmm->wa_dma_data, dmm->wa_dma_handle);
}

/* simple allocator to grab next 16 byte aligned memory from txn */
static void *alloc_dma(struct dmm_txn *txn, size_t sz, dma_addr_t *pa)
{
        void *ptr;
        struct refill_engine *engine = txn->engine_handle;

        /* dmm programming requires 16 byte aligned addresses */
        txn->current_pa = round_up(txn->current_pa, 16);
        txn->current_va = (void *)round_up((long)txn->current_va, 16);

        ptr = txn->current_va;
        *pa = txn->current_pa;

        txn->current_pa += sz;
        txn->current_va += sz;

        BUG_ON((txn->current_va - engine->refill_va) > REFILL_BUFFER_SIZE);

        return ptr;
}

/* check status and spin until wait_mask comes true */
static int wait_status(struct refill_engine *engine, u32 wait_mask)
{
        struct dmm *dmm = engine->dmm;
        u32 r = 0, err, i;

        i = DMM_FIXED_RETRY_COUNT;
        while (true) {
                r = dmm_read(dmm, reg[PAT_STATUS][engine->id]);
                err = r & DMM_PATSTATUS_ERR;
                if (err) {
                        dev_err(dmm->dev,
                                "%s: error (engine%d). PAT_STATUS: 0x%08x\n",
                                __func__, engine->id, r);
                        return -EFAULT;
                }

                if ((r & wait_mask) == wait_mask)
                        break;

                if (--i == 0) {
                        dev_err(dmm->dev,
                                "%s: timeout (engine%d). PAT_STATUS: 0x%08x\n",
                                __func__, engine->id, r);
                        return -ETIMEDOUT;
                }

                udelay(1);
        }

        return 0;
}

static void release_engine(struct refill_engine *engine)
{
        unsigned long flags;

        spin_lock_irqsave(&list_lock, flags);
        list_add(&engine->idle_node, &omap_dmm->idle_head);
        spin_unlock_irqrestore(&list_lock, flags);

        atomic_inc(&omap_dmm->engine_counter);
        wake_up_interruptible(&omap_dmm->engine_queue);
}

static irqreturn_t omap_dmm_irq_handler(int irq, void *arg)
{
        struct dmm *dmm = arg;
        u32 status = dmm_read(dmm, DMM_PAT_IRQSTATUS);
        int i;

        /* ack IRQ */
        dmm_write(dmm, status, DMM_PAT_IRQSTATUS);

        for (i = 0; i < dmm->num_engines; i++) {
                if (status & DMM_IRQSTAT_ERR_MASK)
                        dev_err(dmm->dev,
                                "irq error(engine%d): IRQSTAT 0x%02x\n",
                                i, status & 0xff);

                if (status & DMM_IRQSTAT_LST) {
                        if (dmm->engines[i].async)
                                release_engine(&dmm->engines[i]);

                        complete(&dmm->engines[i].compl);
                }

                status >>= 8;
        }

        return IRQ_HANDLED;
}

/*
 * Get a handle for a DMM transaction
 */
static struct dmm_txn *dmm_txn_init(struct dmm *dmm, struct tcm *tcm)
{
        struct dmm_txn *txn = NULL;
        struct refill_engine *engine = NULL;
        int ret;
        unsigned long flags;


        /* wait until an engine is available */
        ret = wait_event_interruptible(omap_dmm->engine_queue,
                atomic_add_unless(&omap_dmm->engine_counter, -1, 0));
        if (ret)
                return ERR_PTR(ret);

        /* grab an idle engine */
        spin_lock_irqsave(&list_lock, flags);
        if (!list_empty(&dmm->idle_head)) {
                engine = list_entry(dmm->idle_head.next, struct refill_engine,
                                        idle_node);
                list_del(&engine->idle_node);
        }
        spin_unlock_irqrestore(&list_lock, flags);

        BUG_ON(!engine);

        txn = &engine->txn;
        engine->tcm = tcm;
        txn->engine_handle = engine;
        txn->last_pat = NULL;
        txn->current_va = engine->refill_va;
        txn->current_pa = engine->refill_pa;

        return txn;
}

/*
 * Add region to DMM transaction.  If pages or pages[i] is NULL, then the
 * corresponding slot is cleared (ie. dummy_pa is programmed)
 */
static void dmm_txn_append(struct dmm_txn *txn, struct pat_area *area,
                struct page **pages, u32 npages, u32 roll)
{
        dma_addr_t pat_pa = 0, data_pa = 0;
        u32 *data;
        struct pat *pat;
        struct refill_engine *engine = txn->engine_handle;
        int columns = (1 + area->x1 - area->x0);
        int rows = (1 + area->y1 - area->y0);
        int i = columns*rows;

        pat = alloc_dma(txn, sizeof(*pat), &pat_pa);

        if (txn->last_pat)
                txn->last_pat->next_pa = (u32)pat_pa;

        pat->area = *area;

        /* adjust Y coordinates based off of container parameters */
        pat->area.y0 += engine->tcm->y_offset;
        pat->area.y1 += engine->tcm->y_offset;

        pat->ctrl = (struct pat_ctrl){
                        .start = 1,
                        .lut_id = engine->tcm->lut_id,
                };

        data = alloc_dma(txn, 4*i, &data_pa);
        /* FIXME: what if data_pa is more than 32-bit ? */
        pat->data_pa = data_pa;

        while (i--) {
                int n = i + roll;
                if (n >= npages)
                        n -= npages;
                data[i] = (pages && pages[n]) ?
                        page_to_phys(pages[n]) : engine->dmm->dummy_pa;
        }

        txn->last_pat = pat;

        return;
}

/*
 * Commit the DMM transaction.
 */
static int dmm_txn_commit(struct dmm_txn *txn, bool wait)
{
        int ret = 0;
        struct refill_engine *engine = txn->engine_handle;
        struct dmm *dmm = engine->dmm;

        if (!txn->last_pat) {
                dev_err(engine->dmm->dev, "need at least one txn\n");
                ret = -EINVAL;
                goto cleanup;
        }

        txn->last_pat->next_pa = 0;
        /* ensure that the written descriptors are visible to DMM */
        wmb();

        /*
         * NOTE: the wmb() above should be enough, but there seems to be a bug
         * in OMAP's memory barrier implementation, which in some rare cases may
         * cause the writes not to be observable after wmb().
         */

        /* read back to ensure the data is in RAM */
        readl(&txn->last_pat->next_pa);

        /* write to PAT_DESCR to clear out any pending transaction */
        dmm_write(dmm, 0x0, reg[PAT_DESCR][engine->id]);

        /* wait for engine ready: */
        ret = wait_status(engine, DMM_PATSTATUS_READY);
        if (ret) {
                ret = -EFAULT;
                goto cleanup;
        }

        /* mark whether it is async to denote list management in IRQ handler */
        engine->async = wait ? false : true;
        reinit_completion(&engine->compl);
        /* verify that the irq handler sees the 'async' and completion value */
        smp_mb();

        /* kick reload */
        dmm_write(dmm, engine->refill_pa, reg[PAT_DESCR][engine->id]);

        if (wait) {
                if (!wait_for_completion_timeout(&engine->compl,
                                msecs_to_jiffies(100))) {
                        dev_err(dmm->dev, "timed out waiting for done\n");
                        ret = -ETIMEDOUT;
                        goto cleanup;
                }

                /* Check the engine status before continue */
                ret = wait_status(engine, DMM_PATSTATUS_READY |
                                  DMM_PATSTATUS_VALID | DMM_PATSTATUS_DONE);
        }

cleanup:
        /* only place engine back on list if we are done with it */
        if (ret || wait)
                release_engine(engine);

        return ret;
}

/*
 * DMM programming
 */
static int fill(struct tcm_area *area, struct page **pages,
                u32 npages, u32 roll, bool wait)
{
        int ret = 0;
        struct tcm_area slice, area_s;
        struct dmm_txn *txn;

        /*
         * FIXME
         *
         * Asynchronous fill does not work reliably, as the driver does not
         * handle errors in the async code paths. The fill operation may
         * silently fail, leading to leaking DMM engines, which may eventually
         * lead to deadlock if we run out of DMM engines.
         *
         * For now, always set 'wait' so that we only use sync fills. Async
         * fills should be fixed, or alternatively we could decide to only
         * support sync fills and so the whole async code path could be removed.
         */

        wait = true;

        txn = dmm_txn_init(omap_dmm, area->tcm);
        if (IS_ERR_OR_NULL(txn))
                return -ENOMEM;

        tcm_for_each_slice(slice, *area, area_s) {
                struct pat_area p_area = {
                                .x0 = slice.p0.x,  .y0 = slice.p0.y,
                                .x1 = slice.p1.x,  .y1 = slice.p1.y,
                };

                dmm_txn_append(txn, &p_area, pages, npages, roll);

                roll += tcm_sizeof(slice);
        }

        ret = dmm_txn_commit(txn, wait);

        return ret;
}

/*
 * Pin/unpin
 */

/* note: slots for which pages[i] == NULL are filled w/ dummy page
 */
int tiler_pin(struct tiler_block *block, struct page **pages,
                u32 npages, u32 roll, bool wait)
{
        int ret;

        ret = fill(&block->area, pages, npages, roll, wait);

        if (ret)
                tiler_unpin(block);

        return ret;
}

int tiler_unpin(struct tiler_block *block)
{
        return fill(&block->area, NULL, 0, 0, false);
}

/*
 * Reserve/release
 */
struct tiler_block *tiler_reserve_2d(enum tiler_fmt fmt, u16 w,
                u16 h, u16 align)
{
        struct tiler_block *block;
        u32 min_align = 128;
        int ret;
        unsigned long flags;
        u32 slot_bytes;

        block = kzalloc(sizeof(*block), GFP_KERNEL);
        if (!block)
                return ERR_PTR(-ENOMEM);

        BUG_ON(!validfmt(fmt));

        /* convert width/height to slots */
        w = DIV_ROUND_UP(w, geom[fmt].slot_w);
        h = DIV_ROUND_UP(h, geom[fmt].slot_h);

        /* convert alignment to slots */
        slot_bytes = geom[fmt].slot_w * geom[fmt].cpp;
        min_align = max(min_align, slot_bytes);
        align = (align > min_align) ? ALIGN(align, min_align) : min_align;
        align /= slot_bytes;

        block->fmt = fmt;

        ret = tcm_reserve_2d(containers[fmt], w, h, align, -1, slot_bytes,
                        &block->area);
        if (ret) {
                kfree(block);
                return ERR_PTR(-ENOMEM);
        }

        /* add to allocation list */
        spin_lock_irqsave(&list_lock, flags);
        list_add(&block->alloc_node, &omap_dmm->alloc_head);
        spin_unlock_irqrestore(&list_lock, flags);

        return block;
}

struct tiler_block *tiler_reserve_1d(size_t size)
{
        struct tiler_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
        int num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
        unsigned long flags;

        if (!block)
                return ERR_PTR(-ENOMEM);

        block->fmt = TILFMT_PAGE;

        if (tcm_reserve_1d(containers[TILFMT_PAGE], num_pages,
                                &block->area)) {
                kfree(block);
                return ERR_PTR(-ENOMEM);
        }

        spin_lock_irqsave(&list_lock, flags);
        list_add(&block->alloc_node, &omap_dmm->alloc_head);
        spin_unlock_irqrestore(&list_lock, flags);

        return block;
}

/* note: if you have pin'd pages, you should have already unpin'd first! */
int tiler_release(struct tiler_block *block)
{
        int ret = tcm_free(&block->area);
        unsigned long flags;

        if (block->area.tcm)
                dev_err(omap_dmm->dev, "failed to release block\n");

        spin_lock_irqsave(&list_lock, flags);
        list_del(&block->alloc_node);
        spin_unlock_irqrestore(&list_lock, flags);

        kfree(block);
        return ret;
}

/*
 * Utils
 */

/* calculate the tiler space address of a pixel in a view orientation...
 * below description copied from the display subsystem section of TRM:
 *
 * When the TILER is addressed, the bits:
 *   [28:27] = 0x0 for 8-bit tiled
 *             0x1 for 16-bit tiled
 *             0x2 for 32-bit tiled
 *             0x3 for page mode
 *   [31:29] = 0x0 for 0-degree view
 *             0x1 for 180-degree view + mirroring
 *             0x2 for 0-degree view + mirroring
 *             0x3 for 180-degree view
 *             0x4 for 270-degree view + mirroring
 *             0x5 for 270-degree view
 *             0x6 for 90-degree view
 *             0x7 for 90-degree view + mirroring
 * Otherwise the bits indicated the corresponding bit address to access
 * the SDRAM.
 */
static u32 tiler_get_address(enum tiler_fmt fmt, u32 orient, u32 x, u32 y)
{
        u32 x_bits, y_bits, tmp, x_mask, y_mask, alignment;

        x_bits = CONT_WIDTH_BITS - geom[fmt].x_shft;
        y_bits = CONT_HEIGHT_BITS - geom[fmt].y_shft;
        alignment = geom[fmt].x_shft + geom[fmt].y_shft;

        /* validate coordinate */
        x_mask = MASK(x_bits);
        y_mask = MASK(y_bits);

        if (x < 0 || x > x_mask || y < 0 || y > y_mask) {
                DBG("invalid coords: %u < 0 || %u > %u || %u < 0 || %u > %u",
                                x, x, x_mask, y, y, y_mask);
                return 0;
        }

        /* account for mirroring */
        if (orient & MASK_X_INVERT)
                x ^= x_mask;
        if (orient & MASK_Y_INVERT)
                y ^= y_mask;

        /* get coordinate address */
        if (orient & MASK_XY_FLIP)
                tmp = ((x << y_bits) + y);
        else
                tmp = ((y << x_bits) + x);

        return TIL_ADDR((tmp << alignment), orient, fmt);
}

dma_addr_t tiler_ssptr(struct tiler_block *block)
{
        BUG_ON(!validfmt(block->fmt));

        return TILVIEW_8BIT + tiler_get_address(block->fmt, 0,
                        block->area.p0.x * geom[block->fmt].slot_w,
                        block->area.p0.y * geom[block->fmt].slot_h);
}

dma_addr_t tiler_tsptr(struct tiler_block *block, u32 orient,
                u32 x, u32 y)
{
        struct tcm_pt *p = &block->area.p0;
        BUG_ON(!validfmt(block->fmt));

        return tiler_get_address(block->fmt, orient,
                        (p->x * geom[block->fmt].slot_w) + x,
                        (p->y * geom[block->fmt].slot_h) + y);
}

void tiler_align(enum tiler_fmt fmt, u16 *w, u16 *h)
{
        BUG_ON(!validfmt(fmt));
        *w = round_up(*w, geom[fmt].slot_w);
        *h = round_up(*h, geom[fmt].slot_h);
}

u32 tiler_stride(enum tiler_fmt fmt, u32 orient)
{
        BUG_ON(!validfmt(fmt));

        if (orient & MASK_XY_FLIP)
                return 1 << (CONT_HEIGHT_BITS + geom[fmt].x_shft);
        else
                return 1 << (CONT_WIDTH_BITS + geom[fmt].y_shft);
}

size_t tiler_size(enum tiler_fmt fmt, u16 w, u16 h)
{
        tiler_align(fmt, &w, &h);
        return geom[fmt].cpp * w * h;
}

size_t tiler_vsize(enum tiler_fmt fmt, u16 w, u16 h)
{
        BUG_ON(!validfmt(fmt));
        return round_up(geom[fmt].cpp * w, PAGE_SIZE) * h;
}

u32 tiler_get_cpu_cache_flags(void)
{
        return omap_dmm->plat_data->cpu_cache_flags;
}

bool dmm_is_available(void)
{
        return omap_dmm ? true : false;
}

static int omap_dmm_remove(struct platform_device *dev)
{
        struct tiler_block *block, *_block;
        int i;
        unsigned long flags;

        if (omap_dmm) {
                /* Disable all enabled interrupts */
                dmm_write(omap_dmm, 0x7e7e7e7e, DMM_PAT_IRQENABLE_CLR);
                free_irq(omap_dmm->irq, omap_dmm);

                /* free all area regions */
                spin_lock_irqsave(&list_lock, flags);
                list_for_each_entry_safe(block, _block, &omap_dmm->alloc_head,
                                        alloc_node) {
                        list_del(&block->alloc_node);
                        kfree(block);
                }
                spin_unlock_irqrestore(&list_lock, flags);

                for (i = 0; i < omap_dmm->num_lut; i++)
                        if (omap_dmm->tcm && omap_dmm->tcm[i])
                                omap_dmm->tcm[i]->deinit(omap_dmm->tcm[i]);
                kfree(omap_dmm->tcm);

                kfree(omap_dmm->engines);
                if (omap_dmm->refill_va)
                        dma_free_wc(omap_dmm->dev,
                                    REFILL_BUFFER_SIZE * omap_dmm->num_engines,
                                    omap_dmm->refill_va, omap_dmm->refill_pa);
                if (omap_dmm->dummy_page)
                        __free_page(omap_dmm->dummy_page);

                if (omap_dmm->dmm_workaround)
                        dmm_workaround_uninit(omap_dmm);

                iounmap(omap_dmm->base);
                kfree(omap_dmm);
                omap_dmm = NULL;
        }

        return 0;
}

static int omap_dmm_probe(struct platform_device *dev)
{
        int ret = -EFAULT, i;
        struct tcm_area area = {0};
        u32 hwinfo, pat_geom;
        struct resource *mem;

        omap_dmm = kzalloc(sizeof(*omap_dmm), GFP_KERNEL);
        if (!omap_dmm)
                goto fail;

        /* initialize lists */
        INIT_LIST_HEAD(&omap_dmm->alloc_head);
        INIT_LIST_HEAD(&omap_dmm->idle_head);

        init_waitqueue_head(&omap_dmm->engine_queue);

        if (dev->dev.of_node) {
                const struct of_device_id *match;

                match = of_match_node(dmm_of_match, dev->dev.of_node);
                if (!match) {
                        dev_err(&dev->dev, "failed to find matching device node\n");
                        ret = -ENODEV;
                        goto fail;
                }

                omap_dmm->plat_data = match->data;
        }

        /* lookup hwmod data - base address and irq */
        mem = platform_get_resource(dev, IORESOURCE_MEM, 0);
        if (!mem) {
                dev_err(&dev->dev, "failed to get base address resource\n");
                goto fail;
        }

        omap_dmm->phys_base = mem->start;
        omap_dmm->base = ioremap(mem->start, SZ_2K);

        if (!omap_dmm->base) {
                dev_err(&dev->dev, "failed to get dmm base address\n");
                goto fail;
        }

        omap_dmm->irq = platform_get_irq(dev, 0);
        if (omap_dmm->irq < 0) {
                dev_err(&dev->dev, "failed to get IRQ resource\n");
                goto fail;
        }

        omap_dmm->dev = &dev->dev;

        if (of_machine_is_compatible("ti,dra7")) {
                /*
                 * DRA7 Errata i878 says that MPU should not be used to access
                 * RAM and DMM at the same time. As it's not possible to prevent
                 * MPU accessing RAM, we need to access DMM via a proxy.
                 */
                if (!dmm_workaround_init(omap_dmm)) {
                        omap_dmm->dmm_workaround = true;
                        dev_info(&dev->dev,
                                "workaround for errata i878 in use\n");
                } else {
                        dev_warn(&dev->dev,
                                 "failed to initialize work-around for i878\n");
                }
        }

        hwinfo = dmm_read(omap_dmm, DMM_PAT_HWINFO);
        omap_dmm->num_engines = (hwinfo >> 24) & 0x1F;
        omap_dmm->num_lut = (hwinfo >> 16) & 0x1F;
        omap_dmm->container_width = 256;
        omap_dmm->container_height = 128;

        atomic_set(&omap_dmm->engine_counter, omap_dmm->num_engines);

        /* read out actual LUT width and height */
        pat_geom = dmm_read(omap_dmm, DMM_PAT_GEOMETRY);
        omap_dmm->lut_width = ((pat_geom >> 16) & 0xF) << 5;
        omap_dmm->lut_height = ((pat_geom >> 24) & 0xF) << 5;

        /* increment LUT by one if on OMAP5 */
        /* LUT has twice the height, and is split into a separate container */
        if (omap_dmm->lut_height != omap_dmm->container_height)
                omap_dmm->num_lut++;

        /* initialize DMM registers */
        dmm_write(omap_dmm, 0x88888888, DMM_PAT_VIEW__0);
        dmm_write(omap_dmm, 0x88888888, DMM_PAT_VIEW__1);
        dmm_write(omap_dmm, 0x80808080, DMM_PAT_VIEW_MAP__0);
        dmm_write(omap_dmm, 0x80000000, DMM_PAT_VIEW_MAP_BASE);
        dmm_write(omap_dmm, 0x88888888, DMM_TILER_OR__0);
        dmm_write(omap_dmm, 0x88888888, DMM_TILER_OR__1);

        omap_dmm->dummy_page = alloc_page(GFP_KERNEL | __GFP_DMA32);
        if (!omap_dmm->dummy_page) {
                dev_err(&dev->dev, "could not allocate dummy page\n");
                ret = -ENOMEM;
                goto fail;
        }

        /* set dma mask for device */
        ret = dma_set_coherent_mask(&dev->dev, DMA_BIT_MASK(32));
        if (ret)
                goto fail;

        omap_dmm->dummy_pa = page_to_phys(omap_dmm->dummy_page);

        /* alloc refill memory */
        omap_dmm->refill_va = dma_alloc_wc(&dev->dev,
                                           REFILL_BUFFER_SIZE * omap_dmm->num_engines,
                                           &omap_dmm->refill_pa, GFP_KERNEL);
        if (!omap_dmm->refill_va) {
                dev_err(&dev->dev, "could not allocate refill memory\n");
                ret = -ENOMEM;
                goto fail;
        }

        /* alloc engines */
        omap_dmm->engines = kcalloc(omap_dmm->num_engines,
                                    sizeof(*omap_dmm->engines), GFP_KERNEL);
        if (!omap_dmm->engines) {
                ret = -ENOMEM;
                goto fail;
        }

        for (i = 0; i < omap_dmm->num_engines; i++) {
                omap_dmm->engines[i].id = i;
                omap_dmm->engines[i].dmm = omap_dmm;
                omap_dmm->engines[i].refill_va = omap_dmm->refill_va +
                                                (REFILL_BUFFER_SIZE * i);
                omap_dmm->engines[i].refill_pa = omap_dmm->refill_pa +
                                                (REFILL_BUFFER_SIZE * i);
                init_completion(&omap_dmm->engines[i].compl);

                list_add(&omap_dmm->engines[i].idle_node, &omap_dmm->idle_head);
        }

        omap_dmm->tcm = kcalloc(omap_dmm->num_lut, sizeof(*omap_dmm->tcm),
                                GFP_KERNEL);
        if (!omap_dmm->tcm) {
                ret = -ENOMEM;
                goto fail;
        }

        /* init containers */
        /* Each LUT is associated with a TCM (container manager).  We use the
           lut_id to denote the lut_id used to identify the correct LUT for
           programming during reill operations */
        for (i = 0; i < omap_dmm->num_lut; i++) {
                omap_dmm->tcm[i] = sita_init(omap_dmm->container_width,
                                                omap_dmm->container_height);

                if (!omap_dmm->tcm[i]) {
                        dev_err(&dev->dev, "failed to allocate container\n");
                        ret = -ENOMEM;
                        goto fail;
                }

                omap_dmm->tcm[i]->lut_id = i;
        }

        /* assign access mode containers to applicable tcm container */
        /* OMAP 4 has 1 container for all 4 views */
        /* OMAP 5 has 2 containers, 1 for 2D and 1 for 1D */
        containers[TILFMT_8BIT] = omap_dmm->tcm[0];
        containers[TILFMT_16BIT] = omap_dmm->tcm[0];
        containers[TILFMT_32BIT] = omap_dmm->tcm[0];

        if (omap_dmm->container_height != omap_dmm->lut_height) {
                /* second LUT is used for PAGE mode.  Programming must use
                   y offset that is added to all y coordinates.  LUT id is still
                   0, because it is the same LUT, just the upper 128 lines */
                containers[TILFMT_PAGE] = omap_dmm->tcm[1];
                omap_dmm->tcm[1]->y_offset = OMAP5_LUT_OFFSET;
                omap_dmm->tcm[1]->lut_id = 0;
        } else {
                containers[TILFMT_PAGE] = omap_dmm->tcm[0];
        }

        area = (struct tcm_area) {
                .tcm = NULL,
                .p1.x = omap_dmm->container_width - 1,
                .p1.y = omap_dmm->container_height - 1,
        };

        ret = request_irq(omap_dmm->irq, omap_dmm_irq_handler, IRQF_SHARED,
                                "omap_dmm_irq_handler", omap_dmm);

        if (ret) {
                dev_err(&dev->dev, "couldn't register IRQ %d, error %d\n",
                        omap_dmm->irq, ret);
                omap_dmm->irq = -1;
                goto fail;
        }

        /* Enable all interrupts for each refill engine except
         * ERR_LUT_MISS<n> (which is just advisory, and we don't care
         * about because we want to be able to refill live scanout
         * buffers for accelerated pan/scroll) and FILL_DSC<n> which
         * we just generally don't care about.
         */
        dmm_write(omap_dmm, 0x7e7e7e7e, DMM_PAT_IRQENABLE_SET);

        /* initialize all LUTs to dummy page entries */
        for (i = 0; i < omap_dmm->num_lut; i++) {
                area.tcm = omap_dmm->tcm[i];
                if (fill(&area, NULL, 0, 0, true))
                        dev_err(omap_dmm->dev, "refill failed");
        }

        dev_info(omap_dmm->dev, "initialized all PAT entries\n");

        return 0;

fail:
        if (omap_dmm_remove(dev))
                dev_err(&dev->dev, "cleanup failed\n");
        return ret;
}

/*
 * debugfs support

 */

#ifdef CONFIG_DEBUG_FS

static const char *alphabet = "abcdefghijklmnopqrstuvwxyz"
                                "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
static const char *special = ".,:;'\"`~!^-+";

static void fill_map(char **map, int xdiv, int ydiv, struct tcm_area *a,
                                                        char c, bool ovw)
{
        int x, y;
        for (y = a->p0.y / ydiv; y <= a->p1.y / ydiv; y++)
                for (x = a->p0.x / xdiv; x <= a->p1.x / xdiv; x++)
                        if (map[y][x] == ' ' || ovw)
                                map[y][x] = c;
}

static void fill_map_pt(char **map, int xdiv, int ydiv, struct tcm_pt *p,
                                                                        char c)
{
        map[p->y / ydiv][p->x / xdiv] = c;
}

static char read_map_pt(char **map, int xdiv, int ydiv, struct tcm_pt *p)
{
        return map[p->y / ydiv][p->x / xdiv];
}

static int map_width(int xdiv, int x0, int x1)
{
        return (x1 / xdiv) - (x0 / xdiv) + 1;
}

static void text_map(char **map, int xdiv, char *nice, int yd, int x0, int x1)
{
        char *p = map[yd] + (x0 / xdiv);
        int w = (map_width(xdiv, x0, x1) - strlen(nice)) / 2;
        if (w >= 0) {
                p += w;
                while (*nice)
                        *p++ = *nice++;
        }
}

static void map_1d_info(char **map, int xdiv, int ydiv, char *nice,
                                                        struct tcm_area *a)
{
        sprintf(nice, "%dK", tcm_sizeof(*a) * 4);
        if (a->p0.y + 1 < a->p1.y) {
                text_map(map, xdiv, nice, (a->p0.y + a->p1.y) / 2 / ydiv, 0,
                                                        256 - 1);
        } else if (a->p0.y < a->p1.y) {
                if (strlen(nice) < map_width(xdiv, a->p0.x, 256 - 1))
                        text_map(map, xdiv, nice, a->p0.y / ydiv,
                                        a->p0.x + xdiv, 256 - 1);
                else if (strlen(nice) < map_width(xdiv, 0, a->p1.x))
                        text_map(map, xdiv, nice, a->p1.y / ydiv,
                                        0, a->p1.y - xdiv);
        } else if (strlen(nice) + 1 < map_width(xdiv, a->p0.x, a->p1.x)) {
                text_map(map, xdiv, nice, a->p0.y / ydiv, a->p0.x, a->p1.x);
        }
}

static void map_2d_info(char **map, int xdiv, int ydiv, char *nice,
                                                        struct tcm_area *a)
{
        sprintf(nice, "(%d*%d)", tcm_awidth(*a), tcm_aheight(*a));
        if (strlen(nice) + 1 < map_width(xdiv, a->p0.x, a->p1.x))
                text_map(map, xdiv, nice, (a->p0.y + a->p1.y) / 2 / ydiv,
                                                        a->p0.x, a->p1.x);
}

int tiler_map_show(struct seq_file *s, void *arg)
{
        int xdiv = 2, ydiv = 1;
        char **map = NULL, *global_map;
        struct tiler_block *block;
        struct tcm_area a, p;
        int i;
        const char *m2d = alphabet;
        const char *a2d = special;
        const char *m2dp = m2d, *a2dp = a2d;
        char nice[128];
        int h_adj;
        int w_adj;
        unsigned long flags;
        int lut_idx;


        if (!omap_dmm) {
                /* early return if dmm/tiler device is not initialized */
                return 0;
        }

        h_adj = omap_dmm->container_height / ydiv;
        w_adj = omap_dmm->container_width / xdiv;

        map = kmalloc_array(h_adj, sizeof(*map), GFP_KERNEL);
        global_map = kmalloc_array(w_adj + 1, h_adj, GFP_KERNEL);

        if (!map || !global_map)
                goto error;

        for (lut_idx = 0; lut_idx < omap_dmm->num_lut; lut_idx++) {
                memset(map, 0, h_adj * sizeof(*map));
                memset(global_map, ' ', (w_adj + 1) * h_adj);

                for (i = 0; i < omap_dmm->container_height; i++) {
                        map[i] = global_map + i * (w_adj + 1);
                        map[i][w_adj] = 0;
                }

                spin_lock_irqsave(&list_lock, flags);

                list_for_each_entry(block, &omap_dmm->alloc_head, alloc_node) {
                        if (block->area.tcm == omap_dmm->tcm[lut_idx]) {
                                if (block->fmt != TILFMT_PAGE) {
                                        fill_map(map, xdiv, ydiv, &block->area,
                                                *m2dp, true);
                                        if (!*++a2dp)
                                                a2dp = a2d;
                                        if (!*++m2dp)
                                                m2dp = m2d;
                                        map_2d_info(map, xdiv, ydiv, nice,
                                                        &block->area);
                                } else {
                                        bool start = read_map_pt(map, xdiv,
                                                ydiv, &block->area.p0) == ' ';
                                        bool end = read_map_pt(map, xdiv, ydiv,
                                                        &block->area.p1) == ' ';

                                        tcm_for_each_slice(a, block->area, p)
                                                fill_map(map, xdiv, ydiv, &a,
                                                        '=', true);
                                        fill_map_pt(map, xdiv, ydiv,
                                                        &block->area.p0,
                                                        start ? '<' : 'X');
                                        fill_map_pt(map, xdiv, ydiv,
                                                        &block->area.p1,
                                                        end ? '>' : 'X');
                                        map_1d_info(map, xdiv, ydiv, nice,
                                                        &block->area);
                                }
                        }
                }

                spin_unlock_irqrestore(&list_lock, flags);

                if (s) {
                        seq_printf(s, "CONTAINER %d DUMP BEGIN\n", lut_idx);
                        for (i = 0; i < 128; i++)
                                seq_printf(s, "%03d:%s\n", i, map[i]);
                        seq_printf(s, "CONTAINER %d DUMP END\n", lut_idx);
                } else {
                        dev_dbg(omap_dmm->dev, "CONTAINER %d DUMP BEGIN\n",
                                lut_idx);
                        for (i = 0; i < 128; i++)
                                dev_dbg(omap_dmm->dev, "%03d:%s\n", i, map[i]);
                        dev_dbg(omap_dmm->dev, "CONTAINER %d DUMP END\n",
                                lut_idx);
                }
        }

error:
        kfree(map);
        kfree(global_map);

        return 0;
}
#endif

#ifdef CONFIG_PM_SLEEP
static int omap_dmm_resume(struct device *dev)
{
        struct tcm_area area;
        int i;

        if (!omap_dmm)
                return -ENODEV;

        area = (struct tcm_area) {
                .tcm = NULL,
                .p1.x = omap_dmm->container_width - 1,
                .p1.y = omap_dmm->container_height - 1,
        };

        /* initialize all LUTs to dummy page entries */
        for (i = 0; i < omap_dmm->num_lut; i++) {
                area.tcm = omap_dmm->tcm[i];
                if (fill(&area, NULL, 0, 0, true))
                        dev_err(dev, "refill failed");
        }

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(omap_dmm_pm_ops, NULL, omap_dmm_resume);

#if defined(CONFIG_OF)
static const struct dmm_platform_data dmm_omap4_platform_data = {
        .cpu_cache_flags = OMAP_BO_WC,
};

static const struct dmm_platform_data dmm_omap5_platform_data = {
        .cpu_cache_flags = OMAP_BO_UNCACHED,
};

static const struct of_device_id dmm_of_match[] = {
        {
                .compatible = "ti,omap4-dmm",
                .data = &dmm_omap4_platform_data,
        },
        {
                .compatible = "ti,omap5-dmm",
                .data = &dmm_omap5_platform_data,
        },
        {},
};
#endif

struct platform_driver omap_dmm_driver = {
        .probe = omap_dmm_probe,
        .remove = omap_dmm_remove,
        .driver = {
                .owner = THIS_MODULE,
                .name = DMM_DRIVER_NAME,
                .of_match_table = of_match_ptr(dmm_of_match),
                .pm = &omap_dmm_pm_ops,
        },
};

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Andy Gross <andy.gross@ti.com>");
MODULE_DESCRIPTION("OMAP DMM/Tiler Driver");