/*
 * linux/arch/arm/plat-omap/dma.c
 *
 * Copyright (C) 2003 - 2008 Nokia Corporation
 * Author: Juha Yrj\xC3\xB6l\xC3\xA4 <juha.yrjola@nokia.com>
 * DMA channel linking for 1610 by Samuel Ortiz <samuel.ortiz@nokia.com>
 * Graphics DMA and LCD DMA graphics tranformations
 * by Imre Deak <imre.deak@nokia.com>
 * OMAP2/3 support Copyright (C) 2004-2007 Texas Instruments, Inc.
 * Merged to support both OMAP1 and OMAP2 by Tony Lindgren <tony@atomide.com>
 * Some functions based on earlier dma-omap.c Copyright (C) 2001 RidgeRun, Inc.
 *
 * Support functions for the OMAP internal DMA channels.
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>

#include <asm/system.h>
#include <mach/hardware.h>
#include <asm/dma.h>

#include <mach/tc.h>

#undef DEBUG

#ifndef CONFIG_ARCH_OMAP1
enum { DMA_CH_ALLOC_DONE, DMA_CH_PARAMS_SET_DONE, DMA_CH_STARTED,
        DMA_CH_QUEUED, DMA_CH_NOTSTARTED, DMA_CH_PAUSED, DMA_CH_LINK_ENABLED
};

enum { DMA_CHAIN_STARTED, DMA_CHAIN_NOTSTARTED };
#endif

#define OMAP_DMA_ACTIVE                 0x01
#define OMAP_DMA_CCR_EN                 (1 << 7)
#define OMAP2_DMA_CSR_CLEAR_MASK        0xffe

#define OMAP_FUNC_MUX_ARM_BASE          (0xfffe1000 + 0xec)

static int enable_1510_mode;

struct omap_dma_lch {
        int next_lch;
        int dev_id;
        u16 saved_csr;
        u16 enabled_irqs;
        const char *dev_name;
        void (*callback)(int lch, u16 ch_status, void *data);
        void *data;

#ifndef CONFIG_ARCH_OMAP1
        /* required for Dynamic chaining */
        int prev_linked_ch;
        int next_linked_ch;
        int state;
        int chain_id;

        int status;
#endif
        long flags;
};

struct dma_link_info {
        int *linked_dmach_q;
        int no_of_lchs_linked;

        int q_count;
        int q_tail;
        int q_head;

        int chain_state;
        int chain_mode;

};

static struct dma_link_info *dma_linked_lch;

#ifndef CONFIG_ARCH_OMAP1

/* Chain handling macros */
#define OMAP_DMA_CHAIN_QINIT(chain_id)                                  \
        do {                                                            \
                dma_linked_lch[chain_id].q_head =                       \
                dma_linked_lch[chain_id].q_tail =                       \
                dma_linked_lch[chain_id].q_count = 0;                   \
        } while (0)
#define OMAP_DMA_CHAIN_QFULL(chain_id)                                  \
                (dma_linked_lch[chain_id].no_of_lchs_linked ==          \
                dma_linked_lch[chain_id].q_count)
#define OMAP_DMA_CHAIN_QLAST(chain_id)                                  \
        do {                                                            \
                ((dma_linked_lch[chain_id].no_of_lchs_linked-1) ==      \
                dma_linked_lch[chain_id].q_count)                       \
        } while (0)
#define OMAP_DMA_CHAIN_QEMPTY(chain_id)                                 \
                (0 == dma_linked_lch[chain_id].q_count)
#define __OMAP_DMA_CHAIN_INCQ(end)                                      \
        ((end) = ((end)+1) % dma_linked_lch[chain_id].no_of_lchs_linked)
#define OMAP_DMA_CHAIN_INCQHEAD(chain_id)                               \
        do {                                                            \
                __OMAP_DMA_CHAIN_INCQ(dma_linked_lch[chain_id].q_head); \
                dma_linked_lch[chain_id].q_count--;                     \
        } while (0)

#define OMAP_DMA_CHAIN_INCQTAIL(chain_id)                               \
        do {                                                            \
                __OMAP_DMA_CHAIN_INCQ(dma_linked_lch[chain_id].q_tail); \
                dma_linked_lch[chain_id].q_count++; \
        } while (0)
#endif

static int dma_lch_count;
static int dma_chan_count;

static spinlock_t dma_chan_lock;
static struct omap_dma_lch *dma_chan;
static void __iomem *omap_dma_base;

static const u8 omap1_dma_irq[OMAP1_LOGICAL_DMA_CH_COUNT] = {
        INT_DMA_CH0_6, INT_DMA_CH1_7, INT_DMA_CH2_8, INT_DMA_CH3,
        INT_DMA_CH4, INT_DMA_CH5, INT_1610_DMA_CH6, INT_1610_DMA_CH7,
        INT_1610_DMA_CH8, INT_1610_DMA_CH9, INT_1610_DMA_CH10,
        INT_1610_DMA_CH11, INT_1610_DMA_CH12, INT_1610_DMA_CH13,
        INT_1610_DMA_CH14, INT_1610_DMA_CH15, INT_DMA_LCD
};

static inline void disable_lnk(int lch);
static void omap_disable_channel_irq(int lch);
static inline void omap_enable_channel_irq(int lch);

#define REVISIT_24XX()          printk(KERN_ERR "FIXME: no %s on 24xx\n", \
                                                __func__);

#define dma_read(reg)                                                   \
({                                                                      \
        u32 __val;                                                      \
        if (cpu_class_is_omap1())                                       \
                __val = __raw_readw(omap_dma_base + OMAP1_DMA_##reg);   \
        else                                                            \
                __val = __raw_readl(omap_dma_base + OMAP_DMA4_##reg);   \
        __val;                                                          \
})

#define dma_write(val, reg)                                             \
({                                                                      \
        if (cpu_class_is_omap1())                                       \
                __raw_writew((u16)(val), omap_dma_base + OMAP1_DMA_##reg); \
        else                                                            \
                __raw_writel((val), omap_dma_base + OMAP_DMA4_##reg);   \
})

#ifdef CONFIG_ARCH_OMAP15XX
/* Returns 1 if the DMA module is in OMAP1510-compatible mode, 0 otherwise */
int omap_dma_in_1510_mode(void)
{
        return enable_1510_mode;
}
#else
#define omap_dma_in_1510_mode()         0
#endif

#ifdef CONFIG_ARCH_OMAP1
static inline int get_gdma_dev(int req)
{
        u32 reg = OMAP_FUNC_MUX_ARM_BASE + ((req - 1) / 5) * 4;
        int shift = ((req - 1) % 5) * 6;

        return ((omap_readl(reg) >> shift) & 0x3f) + 1;
}

static inline void set_gdma_dev(int req, int dev)
{
        u32 reg = OMAP_FUNC_MUX_ARM_BASE + ((req - 1) / 5) * 4;
        int shift = ((req - 1) % 5) * 6;
        u32 l;

        l = omap_readl(reg);
        l &= ~(0x3f << shift);
        l |= (dev - 1) << shift;
        omap_writel(l, reg);
}
#else
#define set_gdma_dev(req, dev)  do {} while (0)
#endif

/* Omap1 only */
static void clear_lch_regs(int lch)
{
        int i;
        void __iomem *lch_base = omap_dma_base + OMAP1_DMA_CH_BASE(lch);

        for (i = 0; i < 0x2c; i += 2)
                __raw_writew(0, lch_base + i);
}

void omap_set_dma_priority(int lch, int dst_port, int priority)
{
        unsigned long reg;
        u32 l;

        if (cpu_class_is_omap1()) {
                switch (dst_port) {
                case OMAP_DMA_PORT_OCP_T1:      /* FFFECC00 */
                        reg = OMAP_TC_OCPT1_PRIOR;
                        break;
                case OMAP_DMA_PORT_OCP_T2:      /* FFFECCD0 */
                        reg = OMAP_TC_OCPT2_PRIOR;
                        break;
                case OMAP_DMA_PORT_EMIFF:       /* FFFECC08 */
                        reg = OMAP_TC_EMIFF_PRIOR;
                        break;
                case OMAP_DMA_PORT_EMIFS:       /* FFFECC04 */
                        reg = OMAP_TC_EMIFS_PRIOR;
                        break;
                default:
                        BUG();
                        return;
                }
                l = omap_readl(reg);
                l &= ~(0xf << 8);
                l |= (priority & 0xf) << 8;
                omap_writel(l, reg);
        }

        if (cpu_class_is_omap2()) {
                u32 ccr;

                ccr = dma_read(CCR(lch));
                if (priority)
                        ccr |= (1 << 6);
                else
                        ccr &= ~(1 << 6);
                dma_write(ccr, CCR(lch));
        }
}
EXPORT_SYMBOL(omap_set_dma_priority);

void omap_set_dma_transfer_params(int lch, int data_type, int elem_count,
                                  int frame_count, int sync_mode,
                                  int dma_trigger, int src_or_dst_synch)
{
        u32 l;

        l = dma_read(CSDP(lch));
        l &= ~0x03;
        l |= data_type;
        dma_write(l, CSDP(lch));

        if (cpu_class_is_omap1()) {
                u16 ccr;

                ccr = dma_read(CCR(lch));
                ccr &= ~(1 << 5);
                if (sync_mode == OMAP_DMA_SYNC_FRAME)
                        ccr |= 1 << 5;
                dma_write(ccr, CCR(lch));

                ccr = dma_read(CCR2(lch));
                ccr &= ~(1 << 2);
                if (sync_mode == OMAP_DMA_SYNC_BLOCK)
                        ccr |= 1 << 2;
                dma_write(ccr, CCR2(lch));
        }

        if (cpu_class_is_omap2() && dma_trigger) {
                u32 val;

                val = dma_read(CCR(lch));
                val &= ~(3 << 19);
                if (dma_trigger > 63)
                        val |= 1 << 20;
                if (dma_trigger > 31)
                        val |= 1 << 19;

                val &= ~(0x1f);
                val |= (dma_trigger & 0x1f);

                if (sync_mode & OMAP_DMA_SYNC_FRAME)
                        val |= 1 << 5;
                else
                        val &= ~(1 << 5);

                if (sync_mode & OMAP_DMA_SYNC_BLOCK)
                        val |= 1 << 18;
                else
                        val &= ~(1 << 18);

                if (src_or_dst_synch)
                        val |= 1 << 24;         /* source synch */
                else
                        val &= ~(1 << 24);      /* dest synch */

                dma_write(val, CCR(lch));
        }

        dma_write(elem_count, CEN(lch));
        dma_write(frame_count, CFN(lch));
}
EXPORT_SYMBOL(omap_set_dma_transfer_params);

void omap_set_dma_color_mode(int lch, enum omap_dma_color_mode mode, u32 color)
{
        u16 w;

        BUG_ON(omap_dma_in_1510_mode());

        if (cpu_class_is_omap2()) {
                REVISIT_24XX();
                return;
        }

        w = dma_read(CCR2(lch));
        w &= ~0x03;

        switch (mode) {
        case OMAP_DMA_CONSTANT_FILL:
                w |= 0x01;
                break;
        case OMAP_DMA_TRANSPARENT_COPY:
                w |= 0x02;
                break;
        case OMAP_DMA_COLOR_DIS:
                break;
        default:
                BUG();
        }
        dma_write(w, CCR2(lch));

        w = dma_read(LCH_CTRL(lch));
        w &= ~0x0f;
        /* Default is channel type 2D */
        if (mode) {
                dma_write((u16)color, COLOR_L(lch));
                dma_write((u16)(color >> 16), COLOR_U(lch));
                w |= 1;         /* Channel type G */
        }
        dma_write(w, LCH_CTRL(lch));
}
EXPORT_SYMBOL(omap_set_dma_color_mode);

void omap_set_dma_write_mode(int lch, enum omap_dma_write_mode mode)
{
        if (cpu_class_is_omap2()) {
                u32 csdp;

                csdp = dma_read(CSDP(lch));
                csdp &= ~(0x3 << 16);
                csdp |= (mode << 16);
                dma_write(csdp, CSDP(lch));
        }
}
EXPORT_SYMBOL(omap_set_dma_write_mode);

void omap_set_dma_channel_mode(int lch, enum omap_dma_channel_mode mode)
{
        if (cpu_class_is_omap1() && !cpu_is_omap15xx()) {
                u32 l;

                l = dma_read(LCH_CTRL(lch));
                l &= ~0x7;
                l |= mode;
                dma_write(l, LCH_CTRL(lch));
        }
}
EXPORT_SYMBOL(omap_set_dma_channel_mode);

/* Note that src_port is only for omap1 */
void omap_set_dma_src_params(int lch, int src_port, int src_amode,
                             unsigned long src_start,
                             int src_ei, int src_fi)
{
        u32 l;

        if (cpu_class_is_omap1()) {
                u16 w;

                w = dma_read(CSDP(lch));
                w &= ~(0x1f << 2);
                w |= src_port << 2;
                dma_write(w, CSDP(lch));
        }

        l = dma_read(CCR(lch));
        l &= ~(0x03 << 12);
        l |= src_amode << 12;
        dma_write(l, CCR(lch));

        if (cpu_class_is_omap1()) {
                dma_write(src_start >> 16, CSSA_U(lch));
                dma_write((u16)src_start, CSSA_L(lch));
        }

        if (cpu_class_is_omap2())
                dma_write(src_start, CSSA(lch));

        dma_write(src_ei, CSEI(lch));
        dma_write(src_fi, CSFI(lch));
}
EXPORT_SYMBOL(omap_set_dma_src_params);

void omap_set_dma_params(int lch, struct omap_dma_channel_params *params)
{
        omap_set_dma_transfer_params(lch, params->data_type,
                                     params->elem_count, params->frame_count,
                                     params->sync_mode, params->trigger,
                                     params->src_or_dst_synch);
        omap_set_dma_src_params(lch, params->src_port,
                                params->src_amode, params->src_start,
                                params->src_ei, params->src_fi);

        omap_set_dma_dest_params(lch, params->dst_port,
                                 params->dst_amode, params->dst_start,
                                 params->dst_ei, params->dst_fi);
        if (params->read_prio || params->write_prio)
                omap_dma_set_prio_lch(lch, params->read_prio,
                                      params->write_prio);
}
EXPORT_SYMBOL(omap_set_dma_params);

void omap_set_dma_src_index(int lch, int eidx, int fidx)
{
        if (cpu_class_is_omap2())
                return;

        dma_write(eidx, CSEI(lch));
        dma_write(fidx, CSFI(lch));
}
EXPORT_SYMBOL(omap_set_dma_src_index);

void omap_set_dma_src_data_pack(int lch, int enable)
{
        u32 l;

        l = dma_read(CSDP(lch));
        l &= ~(1 << 6);
        if (enable)
                l |= (1 << 6);
        dma_write(l, CSDP(lch));
}
EXPORT_SYMBOL(omap_set_dma_src_data_pack);

void omap_set_dma_src_burst_mode(int lch, enum omap_dma_burst_mode burst_mode)
{
        unsigned int burst = 0;
        u32 l;

        l = dma_read(CSDP(lch));
        l &= ~(0x03 << 7);

        switch (burst_mode) {
        case OMAP_DMA_DATA_BURST_DIS:
                break;
        case OMAP_DMA_DATA_BURST_4:
                if (cpu_class_is_omap2())
                        burst = 0x1;
                else
                        burst = 0x2;
                break;
        case OMAP_DMA_DATA_BURST_8:
                if (cpu_class_is_omap2()) {
                        burst = 0x2;
                        break;
                }
                /* not supported by current hardware on OMAP1
                 * w |= (0x03 << 7);
                 * fall through
                 */
        case OMAP_DMA_DATA_BURST_16:
                if (cpu_class_is_omap2()) {
                        burst = 0x3;
                        break;
                }
                /* OMAP1 don't support burst 16
                 * fall through
                 */
        default:
                BUG();
        }

        l |= (burst << 7);
        dma_write(l, CSDP(lch));
}
EXPORT_SYMBOL(omap_set_dma_src_burst_mode);

/* Note that dest_port is only for OMAP1 */
void omap_set_dma_dest_params(int lch, int dest_port, int dest_amode,
                              unsigned long dest_start,
                              int dst_ei, int dst_fi)
{
        u32 l;

        if (cpu_class_is_omap1()) {
                l = dma_read(CSDP(lch));
                l &= ~(0x1f << 9);
                l |= dest_port << 9;
                dma_write(l, CSDP(lch));
        }

        l = dma_read(CCR(lch));
        l &= ~(0x03 << 14);
        l |= dest_amode << 14;
        dma_write(l, CCR(lch));

        if (cpu_class_is_omap1()) {
                dma_write(dest_start >> 16, CDSA_U(lch));
                dma_write(dest_start, CDSA_L(lch));
        }

        if (cpu_class_is_omap2())
                dma_write(dest_start, CDSA(lch));

        dma_write(dst_ei, CDEI(lch));
        dma_write(dst_fi, CDFI(lch));
}
EXPORT_SYMBOL(omap_set_dma_dest_params);

void omap_set_dma_dest_index(int lch, int eidx, int fidx)
{
        if (cpu_class_is_omap2())
                return;

        dma_write(eidx, CDEI(lch));
        dma_write(fidx, CDFI(lch));
}
EXPORT_SYMBOL(omap_set_dma_dest_index);

void omap_set_dma_dest_data_pack(int lch, int enable)
{
        u32 l;

        l = dma_read(CSDP(lch));
        l &= ~(1 << 13);
        if (enable)
                l |= 1 << 13;
        dma_write(l, CSDP(lch));
}
EXPORT_SYMBOL(omap_set_dma_dest_data_pack);

void omap_set_dma_dest_burst_mode(int lch, enum omap_dma_burst_mode burst_mode)
{
        unsigned int burst = 0;
        u32 l;

        l = dma_read(CSDP(lch));
        l &= ~(0x03 << 14);

        switch (burst_mode) {
        case OMAP_DMA_DATA_BURST_DIS:
                break;
        case OMAP_DMA_DATA_BURST_4:
                if (cpu_class_is_omap2())
                        burst = 0x1;
                else
                        burst = 0x2;
                break;
        case OMAP_DMA_DATA_BURST_8:
                if (cpu_class_is_omap2())
                        burst = 0x2;
                else
                        burst = 0x3;
                break;
        case OMAP_DMA_DATA_BURST_16:
                if (cpu_class_is_omap2()) {
                        burst = 0x3;
                        break;
                }
                /* OMAP1 don't support burst 16
                 * fall through
                 */
        default:
                printk(KERN_ERR "Invalid DMA burst mode\n");
                BUG();
                return;
        }
        l |= (burst << 14);
        dma_write(l, CSDP(lch));
}
EXPORT_SYMBOL(omap_set_dma_dest_burst_mode);

static inline void omap_enable_channel_irq(int lch)
{
        u32 status;

        /* Clear CSR */
        if (cpu_class_is_omap1())
                status = dma_read(CSR(lch));
        else if (cpu_class_is_omap2())
                dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(lch));

        /* Enable some nice interrupts. */
        dma_write(dma_chan[lch].enabled_irqs, CICR(lch));
}

static void omap_disable_channel_irq(int lch)
{
        if (cpu_class_is_omap2())
                dma_write(0, CICR(lch));
}

void omap_enable_dma_irq(int lch, u16 bits)
{
        dma_chan[lch].enabled_irqs |= bits;
}
EXPORT_SYMBOL(omap_enable_dma_irq);

void omap_disable_dma_irq(int lch, u16 bits)
{
        dma_chan[lch].enabled_irqs &= ~bits;
}
EXPORT_SYMBOL(omap_disable_dma_irq);

static inline void enable_lnk(int lch)
{
        u32 l;

        l = dma_read(CLNK_CTRL(lch));

        if (cpu_class_is_omap1())
                l &= ~(1 << 14);

        /* Set the ENABLE_LNK bits */
        if (dma_chan[lch].next_lch != -1)
                l = dma_chan[lch].next_lch | (1 << 15);

#ifndef CONFIG_ARCH_OMAP1
        if (cpu_class_is_omap2())
                if (dma_chan[lch].next_linked_ch != -1)
                        l = dma_chan[lch].next_linked_ch | (1 << 15);
#endif

        dma_write(l, CLNK_CTRL(lch));
}

static inline void disable_lnk(int lch)
{
        u32 l;

        l = dma_read(CLNK_CTRL(lch));

        /* Disable interrupts */
        if (cpu_class_is_omap1()) {
                dma_write(0, CICR(lch));
                /* Set the STOP_LNK bit */
                l |= 1 << 14;
        }

        if (cpu_class_is_omap2()) {
                omap_disable_channel_irq(lch);
                /* Clear the ENABLE_LNK bit */
                l &= ~(1 << 15);
        }

        dma_write(l, CLNK_CTRL(lch));
        dma_chan[lch].flags &= ~OMAP_DMA_ACTIVE;
}

static inline void omap2_enable_irq_lch(int lch)
{
        u32 val;

        if (!cpu_class_is_omap2())
                return;

        val = dma_read(IRQENABLE_L0);
        val |= 1 << lch;
        dma_write(val, IRQENABLE_L0);
}

int omap_request_dma(int dev_id, const char *dev_name,
                     void (*callback)(int lch, u16 ch_status, void *data),
                     void *data, int *dma_ch_out)
{
        int ch, free_ch = -1;
        unsigned long flags;
        struct omap_dma_lch *chan;

        spin_lock_irqsave(&dma_chan_lock, flags);
        for (ch = 0; ch < dma_chan_count; ch++) {
                if (free_ch == -1 && dma_chan[ch].dev_id == -1) {
                        free_ch = ch;
                        if (dev_id == 0)
                                break;
                }
        }
        if (free_ch == -1) {
                spin_unlock_irqrestore(&dma_chan_lock, flags);
                return -EBUSY;
        }
        chan = dma_chan + free_ch;
        chan->dev_id = dev_id;

        if (cpu_class_is_omap1())
                clear_lch_regs(free_ch);

        if (cpu_class_is_omap2())
                omap_clear_dma(free_ch);

        spin_unlock_irqrestore(&dma_chan_lock, flags);

        chan->dev_name = dev_name;
        chan->callback = callback;
        chan->data = data;

#ifndef CONFIG_ARCH_OMAP1
        if (cpu_class_is_omap2()) {
                chan->chain_id = -1;
                chan->next_linked_ch = -1;
        }
#endif

        chan->enabled_irqs = OMAP_DMA_DROP_IRQ | OMAP_DMA_BLOCK_IRQ;

        if (cpu_class_is_omap1())
                chan->enabled_irqs |= OMAP1_DMA_TOUT_IRQ;
        else if (cpu_class_is_omap2())
                chan->enabled_irqs |= OMAP2_DMA_MISALIGNED_ERR_IRQ |
                        OMAP2_DMA_TRANS_ERR_IRQ;

        if (cpu_is_omap16xx()) {
                /* If the sync device is set, configure it dynamically. */
                if (dev_id != 0) {
                        set_gdma_dev(free_ch + 1, dev_id);
                        dev_id = free_ch + 1;
                }
                /*
                 * Disable the 1510 compatibility mode and set the sync device
                 * id.
                 */
                dma_write(dev_id | (1 << 10), CCR(free_ch));
        } else if (cpu_is_omap730() || cpu_is_omap15xx()) {
                dma_write(dev_id, CCR(free_ch));
        }

        if (cpu_class_is_omap2()) {
                omap2_enable_irq_lch(free_ch);
                omap_enable_channel_irq(free_ch);
                /* Clear the CSR register and IRQ status register */
                dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(free_ch));
                dma_write(1 << free_ch, IRQSTATUS_L0);
        }

        *dma_ch_out = free_ch;

        return 0;
}
EXPORT_SYMBOL(omap_request_dma);

void omap_free_dma(int lch)
{
        unsigned long flags;

        spin_lock_irqsave(&dma_chan_lock, flags);
        if (dma_chan[lch].dev_id == -1) {
                pr_err("omap_dma: trying to free unallocated DMA channel %d\n",
                       lch);
                spin_unlock_irqrestore(&dma_chan_lock, flags);
                return;
        }

        dma_chan[lch].dev_id = -1;
        dma_chan[lch].next_lch = -1;
        dma_chan[lch].callback = NULL;
        spin_unlock_irqrestore(&dma_chan_lock, flags);

        if (cpu_class_is_omap1()) {
                /* Disable all DMA interrupts for the channel. */
                dma_write(0, CICR(lch));
                /* Make sure the DMA transfer is stopped. */
                dma_write(0, CCR(lch));
        }

        if (cpu_class_is_omap2()) {
                u32 val;
                /* Disable interrupts */
                val = dma_read(IRQENABLE_L0);
                val &= ~(1 << lch);
                dma_write(val, IRQENABLE_L0);

                /* Clear the CSR register and IRQ status register */
                dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(lch));
                dma_write(1 << lch, IRQSTATUS_L0);

                /* Disable all DMA interrupts for the channel. */
                dma_write(0, CICR(lch));

                /* Make sure the DMA transfer is stopped. */
                dma_write(0, CCR(lch));
                omap_clear_dma(lch);
        }
}
EXPORT_SYMBOL(omap_free_dma);

/**
 * @brief omap_dma_set_global_params : Set global priority settings for dma
 *
 * @param arb_rate
 * @param max_fifo_depth
 * @param tparams - Number of thereads to reserve : DMA_THREAD_RESERVE_NORM
 *                                                  DMA_THREAD_RESERVE_ONET
 *                                                  DMA_THREAD_RESERVE_TWOT
 *                                                  DMA_THREAD_RESERVE_THREET
 */
void
omap_dma_set_global_params(int arb_rate, int max_fifo_depth, int tparams)
{
        u32 reg;

        if (!cpu_class_is_omap2()) {
                printk(KERN_ERR "FIXME: no %s on 15xx/16xx\n", __func__);
                return;
        }

        if (arb_rate == 0)
                arb_rate = 1;

        reg = (arb_rate & 0xff) << 16;
        reg |= (0xff & max_fifo_depth);

        dma_write(reg, GCR);
}
EXPORT_SYMBOL(omap_dma_set_global_params);

/**
 * @brief omap_dma_set_prio_lch : Set channel wise priority settings
 *
 * @param lch
 * @param read_prio - Read priority
 * @param write_prio - Write priority
 * Both of the above can be set with one of the following values :
 *      DMA_CH_PRIO_HIGH/DMA_CH_PRIO_LOW
 */
int
omap_dma_set_prio_lch(int lch, unsigned char read_prio,
                      unsigned char write_prio)
{
        u32 l;

        if (unlikely((lch < 0 || lch >= dma_lch_count))) {
                printk(KERN_ERR "Invalid channel id\n");
                return -EINVAL;
        }
        l = dma_read(CCR(lch));
        l &= ~((1 << 6) | (1 << 26));
        if (cpu_is_omap2430() || cpu_is_omap34xx())
                l |= ((read_prio & 0x1) << 6) | ((write_prio & 0x1) << 26);
        else
                l |= ((read_prio & 0x1) << 6);

        dma_write(l, CCR(lch));

        return 0;
}
EXPORT_SYMBOL(omap_dma_set_prio_lch);

/*
 * Clears any DMA state so the DMA engine is ready to restart with new buffers
 * through omap_start_dma(). Any buffers in flight are discarded.
 */
void omap_clear_dma(int lch)
{
        unsigned long flags;

        local_irq_save(flags);

        if (cpu_class_is_omap1()) {
                u32 l;

                l = dma_read(CCR(lch));
                l &= ~OMAP_DMA_CCR_EN;
                dma_write(l, CCR(lch));

                /* Clear pending interrupts */
                l = dma_read(CSR(lch));
        }

        if (cpu_class_is_omap2()) {
                int i;
                void __iomem *lch_base = omap_dma_base + OMAP_DMA4_CH_BASE(lch);
                for (i = 0; i < 0x44; i += 4)
                        __raw_writel(0, lch_base + i);
        }

        local_irq_restore(flags);
}
EXPORT_SYMBOL(omap_clear_dma);

void omap_start_dma(int lch)
{
        u32 l;

        if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1) {
                int next_lch, cur_lch;
                char dma_chan_link_map[OMAP_DMA4_LOGICAL_DMA_CH_COUNT];

                dma_chan_link_map[lch] = 1;
                /* Set the link register of the first channel */
                enable_lnk(lch);

                memset(dma_chan_link_map, 0, sizeof(dma_chan_link_map));
                cur_lch = dma_chan[lch].next_lch;
                do {
                        next_lch = dma_chan[cur_lch].next_lch;

                        /* The loop case: we've been here already */
                        if (dma_chan_link_map[cur_lch])
                                break;
                        /* Mark the current channel */
                        dma_chan_link_map[cur_lch] = 1;

                        enable_lnk(cur_lch);
                        omap_enable_channel_irq(cur_lch);

                        cur_lch = next_lch;
                } while (next_lch != -1);
        } else if (cpu_class_is_omap2()) {
                /* Errata: Need to write lch even if not using chaining */
                dma_write(lch, CLNK_CTRL(lch));
        }

        omap_enable_channel_irq(lch);

        l = dma_read(CCR(lch));

        /*
         * Errata: On ES2.0 BUFFERING disable must be set.
         * This will always fail on ES1.0
         */
        if (cpu_is_omap24xx())
                l |= OMAP_DMA_CCR_EN;

        l |= OMAP_DMA_CCR_EN;
        dma_write(l, CCR(lch));

        dma_chan[lch].flags |= OMAP_DMA_ACTIVE;
}
EXPORT_SYMBOL(omap_start_dma);

void omap_stop_dma(int lch)
{
        u32 l;

        if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1) {
                int next_lch, cur_lch = lch;
                char dma_chan_link_map[OMAP_DMA4_LOGICAL_DMA_CH_COUNT];

                memset(dma_chan_link_map, 0, sizeof(dma_chan_link_map));
                do {
                        /* The loop case: we've been here already */
                        if (dma_chan_link_map[cur_lch])
                                break;
                        /* Mark the current channel */
                        dma_chan_link_map[cur_lch] = 1;

                        disable_lnk(cur_lch);

                        next_lch = dma_chan[cur_lch].next_lch;
                        cur_lch = next_lch;
                } while (next_lch != -1);

                return;
        }

        /* Disable all interrupts on the channel */
        if (cpu_class_is_omap1())
                dma_write(0, CICR(lch));

        l = dma_read(CCR(lch));
        l &= ~OMAP_DMA_CCR_EN;
        dma_write(l, CCR(lch));

        dma_chan[lch].flags &= ~OMAP_DMA_ACTIVE;
}
EXPORT_SYMBOL(omap_stop_dma);

/*
 * Allows changing the DMA callback function or data. This may be needed if
 * the driver shares a single DMA channel for multiple dma triggers.
 */
int omap_set_dma_callback(int lch,
                          void (*callback)(int lch, u16 ch_status, void *data),
                          void *data)
{
        unsigned long flags;

        if (lch < 0)
                return -ENODEV;

        spin_lock_irqsave(&dma_chan_lock, flags);

        if (dma_chan[lch].dev_id == -1) {
                printk(KERN_ERR "DMA callback for not set for free channel\n");
                spin_unlock_irqrestore(&dma_chan_lock, flags);
                return -EINVAL;
        }
        dma_chan[lch].callback = callback;
        dma_chan[lch].data = data;
        spin_unlock_irqrestore(&dma_chan_lock, flags);

        return 0;
}
EXPORT_SYMBOL(omap_set_dma_callback);

/*
 * Returns current physical source address for the given DMA channel.
 * If the channel is running the caller must disable interrupts prior calling
 * this function and process the returned value before re-enabling interrupt to
 * prevent races with the interrupt handler. Note that in continuous mode there
 * is a chance for CSSA_L register overflow inbetween the two reads resulting
 * in incorrect return value.
 */
dma_addr_t omap_get_dma_src_pos(int lch)
{
        dma_addr_t offset = 0;

        if (cpu_is_omap15xx())
                offset = dma_read(CPC(lch));
        else
                offset = dma_read(CSAC(lch));

        /*
         * omap 3.2/3.3 erratum: sometimes 0 is returned if CSAC/CDAC is
         * read before the DMA controller finished disabling the channel.
         */
        if (!cpu_is_omap15xx() && offset == 0)
                offset = dma_read(CSAC(lch));

        if (cpu_class_is_omap1())
                offset |= (dma_read(CSSA_U(lch)) << 16);

        return offset;
}
EXPORT_SYMBOL(omap_get_dma_src_pos);

/*
 * Returns current physical destination address for the given DMA channel.
 * If the channel is running the caller must disable interrupts prior calling
 * this function and process the returned value before re-enabling interrupt to
 * prevent races with the interrupt handler. Note that in continuous mode there
 * is a chance for CDSA_L register overflow inbetween the two reads resulting
 * in incorrect return value.
 */
dma_addr_t omap_get_dma_dst_pos(int lch)
{
        dma_addr_t offset = 0;

        if (cpu_is_omap15xx())
                offset = dma_read(CPC(lch));
        else
                offset = dma_read(CDAC(lch));

        /*
         * omap 3.2/3.3 erratum: sometimes 0 is returned if CSAC/CDAC is
         * read before the DMA controller finished disabling the channel.
         */
        if (!cpu_is_omap15xx() && offset == 0)
                offset = dma_read(CDAC(lch));

        if (cpu_class_is_omap1())
                offset |= (dma_read(CDSA_U(lch)) << 16);

        return offset;
}
EXPORT_SYMBOL(omap_get_dma_dst_pos);

int omap_get_dma_active_status(int lch)
{
        return (dma_read(CCR(lch)) & OMAP_DMA_CCR_EN) != 0;
}
EXPORT_SYMBOL(omap_get_dma_active_status);

int omap_dma_running(void)
{
        int lch;

        /* Check if LCD DMA is running */
        if (cpu_is_omap16xx())
                if (omap_readw(OMAP1610_DMA_LCD_CCR) & OMAP_DMA_CCR_EN)
                        return 1;

        for (lch = 0; lch < dma_chan_count; lch++)
                if (dma_read(CCR(lch)) & OMAP_DMA_CCR_EN)
                        return 1;

        return 0;
}

/*
 * lch_queue DMA will start right after lch_head one is finished.
 * For this DMA link to start, you still need to start (see omap_start_dma)
 * the first one. That will fire up the entire queue.
 */
void omap_dma_link_lch(int lch_head, int lch_queue)
{
        if (omap_dma_in_1510_mode()) {
                printk(KERN_ERR "DMA linking is not supported in 1510 mode\n");
                BUG();
                return;
        }

        if ((dma_chan[lch_head].dev_id == -1) ||
            (dma_chan[lch_queue].dev_id == -1)) {
                printk(KERN_ERR "omap_dma: trying to link "
                       "non requested channels\n");
                dump_stack();
        }

        dma_chan[lch_head].next_lch = lch_queue;
}
EXPORT_SYMBOL(omap_dma_link_lch);

/*
 * Once the DMA queue is stopped, we can destroy it.
 */
void omap_dma_unlink_lch(int lch_head, int lch_queue)
{
        if (omap_dma_in_1510_mode()) {
                printk(KERN_ERR "DMA linking is not supported in 1510 mode\n");
                BUG();
                return;
        }

        if (dma_chan[lch_head].next_lch != lch_queue ||
            dma_chan[lch_head].next_lch == -1) {
                printk(KERN_ERR "omap_dma: trying to unlink "
                       "non linked channels\n");
                dump_stack();
        }

        if ((dma_chan[lch_head].flags & OMAP_DMA_ACTIVE) ||
            (dma_chan[lch_head].flags & OMAP_DMA_ACTIVE)) {
                printk(KERN_ERR "omap_dma: You need to stop the DMA channels "
                       "before unlinking\n");
                dump_stack();
        }

        dma_chan[lch_head].next_lch = -1;
}
EXPORT_SYMBOL(omap_dma_unlink_lch);

/*----------------------------------------------------------------------------*/

#ifndef CONFIG_ARCH_OMAP1
/* Create chain of DMA channesls */
static void create_dma_lch_chain(int lch_head, int lch_queue)
{
        u32 l;

        /* Check if this is the first link in chain */
        if (dma_chan[lch_head].next_linked_ch == -1) {
                dma_chan[lch_head].next_linked_ch = lch_queue;
                dma_chan[lch_head].prev_linked_ch = lch_queue;
                dma_chan[lch_queue].next_linked_ch = lch_head;
                dma_chan[lch_queue].prev_linked_ch = lch_head;
        }

        /* a link exists, link the new channel in circular chain */
        else {
                dma_chan[lch_queue].next_linked_ch =
                                        dma_chan[lch_head].next_linked_ch;
                dma_chan[lch_queue].prev_linked_ch = lch_head;
                dma_chan[lch_head].next_linked_ch = lch_queue;
                dma_chan[dma_chan[lch_queue].next_linked_ch].prev_linked_ch =
                                        lch_queue;
        }

        l = dma_read(CLNK_CTRL(lch_head));
        l &= ~(0x1f);
        l |= lch_queue;
        dma_write(l, CLNK_CTRL(lch_head));

        l = dma_read(CLNK_CTRL(lch_queue));
        l &= ~(0x1f);
        l |= (dma_chan[lch_queue].next_linked_ch);
        dma_write(l, CLNK_CTRL(lch_queue));
}

/**
 * @brief omap_request_dma_chain : Request a chain of DMA channels
 *
 * @param dev_id - Device id using the dma channel
 * @param dev_name - Device name
 * @param callback - Call back function
 * @chain_id -
 * @no_of_chans - Number of channels requested
 * @chain_mode - Dynamic or static chaining : OMAP_DMA_STATIC_CHAIN
 *                                            OMAP_DMA_DYNAMIC_CHAIN
 * @params - Channel parameters
 *
 * @return - Succes : 0
 *           Failure: -EINVAL/-ENOMEM
 */
int omap_request_dma_chain(int dev_id, const char *dev_name,
                           void (*callback) (int chain_id, u16 ch_status,
                                             void *data),
                           int *chain_id, int no_of_chans, int chain_mode,
                           struct omap_dma_channel_params params)
{
        int *channels;
        int i, err;

        /* Is the chain mode valid ? */
        if (chain_mode != OMAP_DMA_STATIC_CHAIN
                        && chain_mode != OMAP_DMA_DYNAMIC_CHAIN) {
                printk(KERN_ERR "Invalid chain mode requested\n");
                return -EINVAL;
        }

        if (unlikely((no_of_chans < 1
                        || no_of_chans > dma_lch_count))) {
                printk(KERN_ERR "Invalid Number of channels requested\n");
                return -EINVAL;
        }

        /* Allocate a queue to maintain the status of the channels
         * in the chain */
        channels = kmalloc(sizeof(*channels) * no_of_chans, GFP_KERNEL);
        if (channels == NULL) {
                printk(KERN_ERR "omap_dma: No memory for channel queue\n");
                return -ENOMEM;
        }

        /* request and reserve DMA channels for the chain */
        for (i = 0; i < no_of_chans; i++) {
                err = omap_request_dma(dev_id, dev_name,
                                        callback, 0, &channels[i]);
                if (err < 0) {
                        int j;
                        for (j = 0; j < i; j++)
                                omap_free_dma(channels[j]);
                        kfree(channels);
                        printk(KERN_ERR "omap_dma: Request failed %d\n", err);
                        return err;
                }
                dma_chan[channels[i]].prev_linked_ch = -1;
                dma_chan[channels[i]].state = DMA_CH_NOTSTARTED;

                /*
                 * Allowing client drivers to set common parameters now,
                 * so that later only relevant (src_start, dest_start
                 * and element count) can be set
                 */
                omap_set_dma_params(channels[i], &params);
        }

        *chain_id = channels[0];
        dma_linked_lch[*chain_id].linked_dmach_q = channels;
        dma_linked_lch[*chain_id].chain_mode = chain_mode;
        dma_linked_lch[*chain_id].chain_state = DMA_CHAIN_NOTSTARTED;
        dma_linked_lch[*chain_id].no_of_lchs_linked = no_of_chans;

        for (i = 0; i < no_of_chans; i++)
                dma_chan[channels[i]].chain_id = *chain_id;

        /* Reset the Queue pointers */
        OMAP_DMA_CHAIN_QINIT(*chain_id);

        /* Set up the chain */
        if (no_of_chans == 1)
                create_dma_lch_chain(channels[0], channels[0]);
        else {
                for (i = 0; i < (no_of_chans - 1); i++)
                        create_dma_lch_chain(channels[i], channels[i + 1]);
        }

        return 0;
}
EXPORT_SYMBOL(omap_request_dma_chain);

/**
 * @brief omap_modify_dma_chain_param : Modify the chain's params - Modify the
 * params after setting it. Dont do this while dma is running!!
 *
 * @param chain_id - Chained logical channel id.
 * @param params
 *
 * @return - Success : 0
 *           Failure : -EINVAL
 */
int omap_modify_dma_chain_params(int chain_id,
                                struct omap_dma_channel_params params)
{
        int *channels;
        u32 i;

        /* Check for input params */
        if (unlikely((chain_id < 0
                        || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }
        channels = dma_linked_lch[chain_id].linked_dmach_q;

        for (i = 0; i < dma_linked_lch[chain_id].no_of_lchs_linked; i++) {
                /*
                 * Allowing client drivers to set common parameters now,
                 * so that later only relevant (src_start, dest_start
                 * and element count) can be set
                 */
                omap_set_dma_params(channels[i], &params);
        }

        return 0;
}
EXPORT_SYMBOL(omap_modify_dma_chain_params);

/**
 * @brief omap_free_dma_chain - Free all the logical channels in a chain.
 *
 * @param chain_id
 *
 * @return - Success : 0
 *           Failure : -EINVAL
 */
int omap_free_dma_chain(int chain_id)
{
        int *channels;
        u32 i;

        /* Check for input params */
        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }

        channels = dma_linked_lch[chain_id].linked_dmach_q;
        for (i = 0; i < dma_linked_lch[chain_id].no_of_lchs_linked; i++) {
                dma_chan[channels[i]].next_linked_ch = -1;
                dma_chan[channels[i]].prev_linked_ch = -1;
                dma_chan[channels[i]].chain_id = -1;
                dma_chan[channels[i]].state = DMA_CH_NOTSTARTED;
                omap_free_dma(channels[i]);
        }

        kfree(channels);

        dma_linked_lch[chain_id].linked_dmach_q = NULL;
        dma_linked_lch[chain_id].chain_mode = -1;
        dma_linked_lch[chain_id].chain_state = -1;

        return (0);
}
EXPORT_SYMBOL(omap_free_dma_chain);

/**
 * @brief omap_dma_chain_status - Check if the chain is in
 * active / inactive state.
 * @param chain_id
 *
 * @return - Success : OMAP_DMA_CHAIN_ACTIVE/OMAP_DMA_CHAIN_INACTIVE
 *           Failure : -EINVAL
 */
int omap_dma_chain_status(int chain_id)
{
        /* Check for input params */
        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }
        pr_debug("CHAINID=%d, qcnt=%d\n", chain_id,
                        dma_linked_lch[chain_id].q_count);

        if (OMAP_DMA_CHAIN_QEMPTY(chain_id))
                return OMAP_DMA_CHAIN_INACTIVE;

        return OMAP_DMA_CHAIN_ACTIVE;
}
EXPORT_SYMBOL(omap_dma_chain_status);

/**
 * @brief omap_dma_chain_a_transfer - Get a free channel from a chain,
 * set the params and start the transfer.
 *
 * @param chain_id
 * @param src_start - buffer start address
 * @param dest_start - Dest address
 * @param elem_count
 * @param frame_count
 * @param callbk_data - channel callback parameter data.
 *
 * @return  - Success : 0
 *            Failure: -EINVAL/-EBUSY
 */
int omap_dma_chain_a_transfer(int chain_id, int src_start, int dest_start,
                        int elem_count, int frame_count, void *callbk_data)
{
        int *channels;
        u32 l, lch;
        int start_dma = 0;

        /*
         * if buffer size is less than 1 then there is
         * no use of starting the chain
         */
        if (elem_count < 1) {
                printk(KERN_ERR "Invalid buffer size\n");
                return -EINVAL;
        }

        /* Check for input params */
        if (unlikely((chain_id < 0
                        || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exist\n");
                return -EINVAL;
        }

        /* Check if all the channels in chain are in use */
        if (OMAP_DMA_CHAIN_QFULL(chain_id))
                return -EBUSY;

        /* Frame count may be negative in case of indexed transfers */
        channels = dma_linked_lch[chain_id].linked_dmach_q;

        /* Get a free channel */
        lch = channels[dma_linked_lch[chain_id].q_tail];

        /* Store the callback data */
        dma_chan[lch].data = callbk_data;

        /* Increment the q_tail */
        OMAP_DMA_CHAIN_INCQTAIL(chain_id);

        /* Set the params to the free channel */
        if (src_start != 0)
                dma_write(src_start, CSSA(lch));
        if (dest_start != 0)
                dma_write(dest_start, CDSA(lch));

        /* Write the buffer size */
        dma_write(elem_count, CEN(lch));
        dma_write(frame_count, CFN(lch));

        /*
         * If the chain is dynamically linked,
         * then we may have to start the chain if its not active
         */
        if (dma_linked_lch[chain_id].chain_mode == OMAP_DMA_DYNAMIC_CHAIN) {

                /*
                 * In Dynamic chain, if the chain is not started,
                 * queue the channel
                 */
                if (dma_linked_lch[chain_id].chain_state ==
                                                DMA_CHAIN_NOTSTARTED) {
                        /* Enable the link in previous channel */
                        if (dma_chan[dma_chan[lch].prev_linked_ch].state ==
                                                                DMA_CH_QUEUED)
                                enable_lnk(dma_chan[lch].prev_linked_ch);
                        dma_chan[lch].state = DMA_CH_QUEUED;
                }

                /*
                 * Chain is already started, make sure its active,
                 * if not then start the chain
                 */
                else {
                        start_dma = 1;

                        if (dma_chan[dma_chan[lch].prev_linked_ch].state ==
                                                        DMA_CH_STARTED) {
                                enable_lnk(dma_chan[lch].prev_linked_ch);
                                dma_chan[lch].state = DMA_CH_QUEUED;
                                start_dma = 0;
                                if (0 == ((1 << 7) & dma_read(
                                        CCR(dma_chan[lch].prev_linked_ch)))) {
                                        disable_lnk(dma_chan[lch].
                                                    prev_linked_ch);
                                        pr_debug("\n prev ch is stopped\n");
                                        start_dma = 1;
                                }
                        }

                        else if (dma_chan[dma_chan[lch].prev_linked_ch].state
                                                        == DMA_CH_QUEUED) {
                                enable_lnk(dma_chan[lch].prev_linked_ch);
                                dma_chan[lch].state = DMA_CH_QUEUED;
                                start_dma = 0;
                        }
                        omap_enable_channel_irq(lch);

                        l = dma_read(CCR(lch));

                        if ((0 == (l & (1 << 24))))
                                l &= ~(1 << 25);
                        else
                                l |= (1 << 25);
                        if (start_dma == 1) {
                                if (0 == (l & (1 << 7))) {
                                        l |= (1 << 7);
                                        dma_chan[lch].state = DMA_CH_STARTED;
                                        pr_debug("starting %d\n", lch);
                                        dma_write(l, CCR(lch));
                                } else
                                        start_dma = 0;
                        } else {
                                if (0 == (l & (1 << 7)))
                                        dma_write(l, CCR(lch));
                        }
                        dma_chan[lch].flags |= OMAP_DMA_ACTIVE;
                }
        }

        return 0;
}
EXPORT_SYMBOL(omap_dma_chain_a_transfer);

/**
 * @brief omap_start_dma_chain_transfers - Start the chain
 *
 * @param chain_id
 *
 * @return - Success : 0
 *           Failure : -EINVAL/-EBUSY
 */
int omap_start_dma_chain_transfers(int chain_id)
{
        int *channels;
        u32 l, i;

        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        channels = dma_linked_lch[chain_id].linked_dmach_q;

        if (dma_linked_lch[channels[0]].chain_state == DMA_CHAIN_STARTED) {
                printk(KERN_ERR "Chain is already started\n");
                return -EBUSY;
        }

        if (dma_linked_lch[chain_id].chain_mode == OMAP_DMA_STATIC_CHAIN) {
                for (i = 0; i < dma_linked_lch[chain_id].no_of_lchs_linked;
                                                                        i++) {
                        enable_lnk(channels[i]);
                        omap_enable_channel_irq(channels[i]);
                }
        } else {
                omap_enable_channel_irq(channels[0]);
        }

        l = dma_read(CCR(channels[0]));
        l |= (1 << 7);
        dma_linked_lch[chain_id].chain_state = DMA_CHAIN_STARTED;
        dma_chan[channels[0]].state = DMA_CH_STARTED;

        if ((0 == (l & (1 << 24))))
                l &= ~(1 << 25);
        else
                l |= (1 << 25);
        dma_write(l, CCR(channels[0]));

        dma_chan[channels[0]].flags |= OMAP_DMA_ACTIVE;

        return 0;
}
EXPORT_SYMBOL(omap_start_dma_chain_transfers);

/**
 * @brief omap_stop_dma_chain_transfers - Stop the dma transfer of a chain.
 *
 * @param chain_id
 *
 * @return - Success : 0
 *           Failure : EINVAL
 */
int omap_stop_dma_chain_transfers(int chain_id)
{
        int *channels;
        u32 l, i;
        u32 sys_cf;

        /* Check for input params */
        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }
        channels = dma_linked_lch[chain_id].linked_dmach_q;

        /*
         * DMA Errata:
         * Special programming model needed to disable DMA before end of block
         */
        sys_cf = dma_read(OCP_SYSCONFIG);
        l = sys_cf;
        /* Middle mode reg set no Standby */
        l &= ~((1 << 12)|(1 << 13));
        dma_write(l, OCP_SYSCONFIG);

        for (i = 0; i < dma_linked_lch[chain_id].no_of_lchs_linked; i++) {

                /* Stop the Channel transmission */
                l = dma_read(CCR(channels[i]));
                l &= ~(1 << 7);
                dma_write(l, CCR(channels[i]));

                /* Disable the link in all the channels */
                disable_lnk(channels[i]);
                dma_chan[channels[i]].state = DMA_CH_NOTSTARTED;

        }
        dma_linked_lch[chain_id].chain_state = DMA_CHAIN_NOTSTARTED;

        /* Reset the Queue pointers */
        OMAP_DMA_CHAIN_QINIT(chain_id);

        /* Errata - put in the old value */
        dma_write(sys_cf, OCP_SYSCONFIG);

        return 0;
}
EXPORT_SYMBOL(omap_stop_dma_chain_transfers);

/* Get the index of the ongoing DMA in chain */
/**
 * @brief omap_get_dma_chain_index - Get the element and frame index
 * of the ongoing DMA in chain
 *
 * @param chain_id
 * @param ei - Element index
 * @param fi - Frame index
 *
 * @return - Success : 0
 *           Failure : -EINVAL
 */
int omap_get_dma_chain_index(int chain_id, int *ei, int *fi)
{
        int lch;
        int *channels;

        /* Check for input params */
        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }
        if ((!ei) || (!fi))
                return -EINVAL;

        channels = dma_linked_lch[chain_id].linked_dmach_q;

        /* Get the current channel */
        lch = channels[dma_linked_lch[chain_id].q_head];

        *ei = dma_read(CCEN(lch));
        *fi = dma_read(CCFN(lch));

        return 0;
}
EXPORT_SYMBOL(omap_get_dma_chain_index);

/**
 * @brief omap_get_dma_chain_dst_pos - Get the destination position of the
 * ongoing DMA in chain
 *
 * @param chain_id
 *
 * @return - Success : Destination position
 *           Failure : -EINVAL
 */
int omap_get_dma_chain_dst_pos(int chain_id)
{
        int lch;
        int *channels;

        /* Check for input params */
        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }

        channels = dma_linked_lch[chain_id].linked_dmach_q;

        /* Get the current channel */
        lch = channels[dma_linked_lch[chain_id].q_head];

        return dma_read(CDAC(lch));
}
EXPORT_SYMBOL(omap_get_dma_chain_dst_pos);

/**
 * @brief omap_get_dma_chain_src_pos - Get the source position
 * of the ongoing DMA in chain
 * @param chain_id
 *
 * @return - Success : Destination position
 *           Failure : -EINVAL
 */
int omap_get_dma_chain_src_pos(int chain_id)
{
        int lch;
        int *channels;

        /* Check for input params */
        if (unlikely((chain_id < 0 || chain_id >= dma_lch_count))) {
                printk(KERN_ERR "Invalid chain id\n");
                return -EINVAL;
        }

        /* Check if the chain exists */
        if (dma_linked_lch[chain_id].linked_dmach_q == NULL) {
                printk(KERN_ERR "Chain doesn't exists\n");
                return -EINVAL;
        }

        channels = dma_linked_lch[chain_id].linked_dmach_q;

        /* Get the current channel */
        lch = channels[dma_linked_lch[chain_id].q_head];

        return dma_read(CSAC(lch));
}
EXPORT_SYMBOL(omap_get_dma_chain_src_pos);
#endif  /* ifndef CONFIG_ARCH_OMAP1 */

/*----------------------------------------------------------------------------*/

#ifdef CONFIG_ARCH_OMAP1

static int omap1_dma_handle_ch(int ch)
{
        u32 csr;

        if (enable_1510_mode && ch >= 6) {
                csr = dma_chan[ch].saved_csr;
                dma_chan[ch].saved_csr = 0;
        } else
                csr = dma_read(CSR(ch));
        if (enable_1510_mode && ch <= 2 && (csr >> 7) != 0) {
                dma_chan[ch + 6].saved_csr = csr >> 7;
                csr &= 0x7f;
        }
        if ((csr & 0x3f) == 0)
                return 0;
        if (unlikely(dma_chan[ch].dev_id == -1)) {
                printk(KERN_WARNING "Spurious interrupt from DMA channel "
                       "%d (CSR %04x)\n", ch, csr);
                return 0;
        }
        if (unlikely(csr & OMAP1_DMA_TOUT_IRQ))
                printk(KERN_WARNING "DMA timeout with device %d\n",
                       dma_chan[ch].dev_id);
        if (unlikely(csr & OMAP_DMA_DROP_IRQ))
                printk(KERN_WARNING "DMA synchronization event drop occurred "
                       "with device %d\n", dma_chan[ch].dev_id);
        if (likely(csr & OMAP_DMA_BLOCK_IRQ))
                dma_chan[ch].flags &= ~OMAP_DMA_ACTIVE;
        if (likely(dma_chan[ch].callback != NULL))
                dma_chan[ch].callback(ch, csr, dma_chan[ch].data);

        return 1;
}

static irqreturn_t omap1_dma_irq_handler(int irq, void *dev_id)
{
        int ch = ((int) dev_id) - 1;
        int handled = 0;

        for (;;) {
                int handled_now = 0;

                handled_now += omap1_dma_handle_ch(ch);
                if (enable_1510_mode && dma_chan[ch + 6].saved_csr)
                        handled_now += omap1_dma_handle_ch(ch + 6);
                if (!handled_now)
                        break;
                handled += handled_now;
        }

        return handled ? IRQ_HANDLED : IRQ_NONE;
}

#else
#define omap1_dma_irq_handler   NULL
#endif

#if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3)

static int omap2_dma_handle_ch(int ch)
{
        u32 status = dma_read(CSR(ch));

        if (!status) {
                if (printk_ratelimit())
                        printk(KERN_WARNING "Spurious DMA IRQ for lch %d\n",
                                ch);
                dma_write(1 << ch, IRQSTATUS_L0);
                return 0;
        }
        if (unlikely(dma_chan[ch].dev_id == -1)) {
                if (printk_ratelimit())
                        printk(KERN_WARNING "IRQ %04x for non-allocated DMA"
                                        "channel %d\n", status, ch);
                return 0;
        }
        if (unlikely(status & OMAP_DMA_DROP_IRQ))
                printk(KERN_INFO
                       "DMA synchronization event drop occurred with device "
                       "%d\n", dma_chan[ch].dev_id);
        if (unlikely(status & OMAP2_DMA_TRANS_ERR_IRQ))
                printk(KERN_INFO "DMA transaction error with device %d\n",
                       dma_chan[ch].dev_id);
        if (unlikely(status & OMAP2_DMA_SECURE_ERR_IRQ))
                printk(KERN_INFO "DMA secure error with device %d\n",
                       dma_chan[ch].dev_id);
        if (unlikely(status & OMAP2_DMA_MISALIGNED_ERR_IRQ))
                printk(KERN_INFO "DMA misaligned error with device %d\n",
                       dma_chan[ch].dev_id);

        dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(ch));
        dma_write(1 << ch, IRQSTATUS_L0);

        /* If the ch is not chained then chain_id will be -1 */
        if (dma_chan[ch].chain_id != -1) {
                int chain_id = dma_chan[ch].chain_id;
                dma_chan[ch].state = DMA_CH_NOTSTARTED;
                if (dma_read(CLNK_CTRL(ch)) & (1 << 15))
                        dma_chan[dma_chan[ch].next_linked_ch].state =
                                                        DMA_CH_STARTED;
                if (dma_linked_lch[chain_id].chain_mode ==
                                                OMAP_DMA_DYNAMIC_CHAIN)
                        disable_lnk(ch);

                if (!OMAP_DMA_CHAIN_QEMPTY(chain_id))
                        OMAP_DMA_CHAIN_INCQHEAD(chain_id);

                status = dma_read(CSR(ch));
        }

        if (likely(dma_chan[ch].callback != NULL))
                dma_chan[ch].callback(ch, status, dma_chan[ch].data);

        dma_write(status, CSR(ch));

        return 0;
}

/* STATUS register count is from 1-32 while our is 0-31 */
static irqreturn_t omap2_dma_irq_handler(int irq, void *dev_id)
{
        u32 val;
        int i;

        val = dma_read(IRQSTATUS_L0);
        if (val == 0) {
                if (printk_ratelimit())
                        printk(KERN_WARNING "Spurious DMA IRQ\n");
                return IRQ_HANDLED;
        }
        for (i = 0; i < dma_lch_count && val != 0; i++) {
                if (val & 1)
                        omap2_dma_handle_ch(i);
                val >>= 1;
        }

        return IRQ_HANDLED;
}

static struct irqaction omap24xx_dma_irq = {
        .name = "DMA",
        .handler = omap2_dma_irq_handler,
        .flags = IRQF_DISABLED
};

#else
static struct irqaction omap24xx_dma_irq;
#endif

/*----------------------------------------------------------------------------*/

static struct lcd_dma_info {
        spinlock_t lock;
        int reserved;
        void (*callback)(u16 status, void *data);
        void *cb_data;

        int active;
        unsigned long addr, size;
        int rotate, data_type, xres, yres;
        int vxres;
        int mirror;
        int xscale, yscale;
        int ext_ctrl;
        int src_port;
        int single_transfer;
} lcd_dma;

void omap_set_lcd_dma_b1(unsigned long addr, u16 fb_xres, u16 fb_yres,
                         int data_type)
{
        lcd_dma.addr = addr;
        lcd_dma.data_type = data_type;
        lcd_dma.xres = fb_xres;
        lcd_dma.yres = fb_yres;
}
EXPORT_SYMBOL(omap_set_lcd_dma_b1);

void omap_set_lcd_dma_src_port(int port)
{
        lcd_dma.src_port = port;
}

void omap_set_lcd_dma_ext_controller(int external)
{
        lcd_dma.ext_ctrl = external;
}
EXPORT_SYMBOL(omap_set_lcd_dma_ext_controller);

void omap_set_lcd_dma_single_transfer(int single)
{
        lcd_dma.single_transfer = single;
}
EXPORT_SYMBOL(omap_set_lcd_dma_single_transfer);

void omap_set_lcd_dma_b1_rotation(int rotate)
{
        if (omap_dma_in_1510_mode()) {
                printk(KERN_ERR "DMA rotation is not supported in 1510 mode\n");
                BUG();
                return;
        }
        lcd_dma.rotate = rotate;
}
EXPORT_SYMBOL(omap_set_lcd_dma_b1_rotation);

void omap_set_lcd_dma_b1_mirror(int mirror)
{
        if (omap_dma_in_1510_mode()) {
                printk(KERN_ERR "DMA mirror is not supported in 1510 mode\n");
                BUG();
        }
        lcd_dma.mirror = mirror;
}
EXPORT_SYMBOL(omap_set_lcd_dma_b1_mirror);

void omap_set_lcd_dma_b1_vxres(unsigned long vxres)
{
        if (omap_dma_in_1510_mode()) {
                printk(KERN_ERR "DMA virtual resulotion is not supported "
                                "in 1510 mode\n");
                BUG();
        }
        lcd_dma.vxres = vxres;
}
EXPORT_SYMBOL(omap_set_lcd_dma_b1_vxres);

void omap_set_lcd_dma_b1_scale(unsigned int xscale, unsigned int yscale)
{
        if (omap_dma_in_1510_mode()) {