Linux 5.7.7

[linux/fpc-iii.git] / arch / arm / plat-omap / dma.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/arch/arm/plat-omap/dma.c
 *
 * Copyright (C) 2003 - 2008 Nokia Corporation
 * Author: Juha Yrjölä <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.
 *
 * Copyright (C) 2009 Texas Instruments
 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
 *
 * Support functions for the OMAP internal DMA channels.
 *
 * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
 * Converted DMA library into DMA platform driver.
 *      - G, Manjunath Kondaiah <manjugk@ti.com>
 */

#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 <linux/slab.h>
#include <linux/delay.h>

#include <linux/omap-dma.h>

#ifdef CONFIG_ARCH_OMAP1
#include <mach/soc.h>
#endif

/*
 * MAX_LOGICAL_DMA_CH_COUNT: the maximum number of logical DMA
 * channels that an instance of the SDMA IP block can support.  Used
 * to size arrays.  (The actual maximum on a particular SoC may be less
 * than this -- for example, OMAP1 SDMA instances only support 17 logical
 * DMA channels.)
 */
#define MAX_LOGICAL_DMA_CH_COUNT                32

#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 OMAP2_DMA_CSR_CLEAR_MASK        0xffffffff

#define OMAP_FUNC_MUX_ARM_BASE          (0xfffe1000 + 0xec)

static struct omap_system_dma_plat_info *p;
static struct omap_dma_dev_attr *d;
static void omap_clear_dma(int lch);
static int enable_1510_mode;
static u32 errata;

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 int dma_lch_count;
static int dma_chan_count;
static int omap_dma_reserve_channels;

static spinlock_t dma_chan_lock;
static struct omap_dma_lch *dma_chan;

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

#ifdef CONFIG_ARCH_OMAP15XX
/* Returns 1 if the DMA module is in OMAP1510-compatible mode, 0 otherwise */
static 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 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)
#define omap_readl(reg)         0
#define omap_writel(val, reg)   do {} while (0)
#endif

#ifdef CONFIG_ARCH_OMAP1
void omap_set_dma_priority(int lch, int dst_port, int priority)
{
        unsigned long reg;
        u32 l;

        if (dma_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);
        }
}
#endif

#ifdef CONFIG_ARCH_OMAP2PLUS
void omap_set_dma_priority(int lch, int dst_port, int priority)
{
        u32 ccr;

        ccr = p->dma_read(CCR, lch);
        if (priority)
                ccr |= (1 << 6);
        else
                ccr &= ~(1 << 6);
        p->dma_write(ccr, CCR, lch);
}
#endif
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 = p->dma_read(CSDP, lch);
        l &= ~0x03;
        l |= data_type;
        p->dma_write(l, CSDP, lch);

        if (dma_omap1()) {
                u16 ccr;

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

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

        if (dma_omap2plus() && dma_trigger) {
                u32 val;

                val = p->dma_read(CCR, lch);

                /* DMA_SYNCHRO_CONTROL_UPPER depends on the channel number */
                val &= ~((1 << 23) | (3 << 19) | 0x1f);
                val |= (dma_trigger & ~0x1f) << 14;
                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 == OMAP_DMA_DST_SYNC_PREFETCH) {
                        val &= ~(1 << 24);      /* dest synch */
                        val |= (1 << 23);       /* Prefetch */
                } else if (src_or_dst_synch) {
                        val |= 1 << 24;         /* source synch */
                } else {
                        val &= ~(1 << 24);      /* dest synch */
                }
                p->dma_write(val, CCR, lch);
        }

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

void omap_set_dma_channel_mode(int lch, enum omap_dma_channel_mode mode)
{
        if (dma_omap1() && !dma_omap15xx()) {
                u32 l;

                l = p->dma_read(LCH_CTRL, lch);
                l &= ~0x7;
                l |= mode;
                p->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 (dma_omap1()) {
                u16 w;

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

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

        p->dma_write(src_start, CSSA, lch);

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

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

        l = p->dma_read(CSDP, lch);
        l &= ~(1 << 6);
        if (enable)
                l |= (1 << 6);
        p->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 = p->dma_read(CSDP, lch);
        l &= ~(0x03 << 7);

        switch (burst_mode) {
        case OMAP_DMA_DATA_BURST_DIS:
                break;
        case OMAP_DMA_DATA_BURST_4:
                if (dma_omap2plus())
                        burst = 0x1;
                else
                        burst = 0x2;
                break;
        case OMAP_DMA_DATA_BURST_8:
                if (dma_omap2plus()) {
                        burst = 0x2;
                        break;
                }
                /*
                 * not supported by current hardware on OMAP1
                 * w |= (0x03 << 7);
                 */
                /* fall through */
        case OMAP_DMA_DATA_BURST_16:
                if (dma_omap2plus()) {
                        burst = 0x3;
                        break;
                }
                /* OMAP1 don't support burst 16 */
                /* fall through */
        default:
                BUG();
        }

        l |= (burst << 7);
        p->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 (dma_omap1()) {
                l = p->dma_read(CSDP, lch);
                l &= ~(0x1f << 9);
                l |= dest_port << 9;
                p->dma_write(l, CSDP, lch);
        }

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

        p->dma_write(dest_start, CDSA, lch);

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

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

        l = p->dma_read(CSDP, lch);
        l &= ~(1 << 13);
        if (enable)
                l |= 1 << 13;
        p->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 = p->dma_read(CSDP, lch);
        l &= ~(0x03 << 14);

        switch (burst_mode) {
        case OMAP_DMA_DATA_BURST_DIS:
                break;
        case OMAP_DMA_DATA_BURST_4:
                if (dma_omap2plus())
                        burst = 0x1;
                else
                        burst = 0x2;
                break;
        case OMAP_DMA_DATA_BURST_8:
                if (dma_omap2plus())
                        burst = 0x2;
                else
                        burst = 0x3;
                break;
        case OMAP_DMA_DATA_BURST_16:
                if (dma_omap2plus()) {
                        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);
        p->dma_write(l, CSDP, lch);
}
EXPORT_SYMBOL(omap_set_dma_dest_burst_mode);

static inline void omap_enable_channel_irq(int lch)
{
        /* Clear CSR */
        if (dma_omap1())
                p->dma_read(CSR, lch);
        else
                p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);

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

static inline void omap_disable_channel_irq(int lch)
{
        /* disable channel interrupts */
        p->dma_write(0, CICR, lch);
        /* Clear CSR */
        if (dma_omap1())
                p->dma_read(CSR, lch);
        else
                p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
}

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 = p->dma_read(CLNK_CTRL, lch);

        if (dma_omap1())
                l &= ~(1 << 14);

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

        p->dma_write(l, CLNK_CTRL, lch);
}

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

        l = p->dma_read(CLNK_CTRL, lch);

        /* Disable interrupts */
        omap_disable_channel_irq(lch);

        if (dma_omap1()) {
                /* Set the STOP_LNK bit */
                l |= 1 << 14;
        }

        if (dma_omap2plus()) {
                /* Clear the ENABLE_LNK bit */
                l &= ~(1 << 15);
        }

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

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;

        WARN(strcmp(dev_name, "DMA engine"), "Using deprecated platform DMA API - please update to DMA engine");

        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;
                        /* Exit after first free channel found */
                        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 (p->clear_lch_regs)
                p->clear_lch_regs(free_ch);

        spin_unlock_irqrestore(&dma_chan_lock, flags);

        chan->dev_name = dev_name;
        chan->callback = callback;
        chan->data = data;
        chan->flags = 0;

        chan->enabled_irqs = OMAP_DMA_DROP_IRQ | OMAP_DMA_BLOCK_IRQ;

        if (dma_omap1())
                chan->enabled_irqs |= OMAP1_DMA_TOUT_IRQ;

        if (dma_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.
                 */
                p->dma_write(dev_id | (1 << 10), CCR, free_ch);
        } else if (dma_omap1()) {
                p->dma_write(dev_id, CCR, free_ch);
        }

        *dma_ch_out = free_ch;

        return 0;
}
EXPORT_SYMBOL(omap_request_dma);

void omap_free_dma(int lch)
{
        unsigned long flags;

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

        /* Disable all DMA interrupts for the channel. */
        omap_disable_channel_irq(lch);

        /* Make sure the DMA transfer is stopped. */
        p->dma_write(0, CCR, lch);

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

/*
 * 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.
 */
static void omap_clear_dma(int lch)
{
        unsigned long flags;

        local_irq_save(flags);
        p->clear_dma(lch);
        local_irq_restore(flags);
}

void omap_start_dma(int lch)
{
        u32 l;

        /*
         * The CPC/CDAC register needs to be initialized to zero
         * before starting dma transfer.
         */
        if (dma_omap15xx())
                p->dma_write(0, CPC, lch);
        else
                p->dma_write(0, CDAC, lch);

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

                /* Set the link register of the first channel */
                enable_lnk(lch);

                memset(dma_chan_link_map, 0, sizeof(dma_chan_link_map));
                dma_chan_link_map[lch] = 1;

                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 (IS_DMA_ERRATA(DMA_ERRATA_PARALLEL_CHANNELS))
                p->dma_write(lch, CLNK_CTRL, lch);

        omap_enable_channel_irq(lch);

        l = p->dma_read(CCR, lch);

        if (IS_DMA_ERRATA(DMA_ERRATA_IFRAME_BUFFERING))
                        l |= OMAP_DMA_CCR_BUFFERING_DISABLE;
        l |= OMAP_DMA_CCR_EN;

        /*
         * As dma_write() uses IO accessors which are weakly ordered, there
         * is no guarantee that data in coherent DMA memory will be visible
         * to the DMA device.  Add a memory barrier here to ensure that any
         * such data is visible prior to enabling DMA.
         */
        mb();
        p->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;

        /* Disable all interrupts on the channel */
        omap_disable_channel_irq(lch);

        l = p->dma_read(CCR, lch);
        if (IS_DMA_ERRATA(DMA_ERRATA_i541) &&
                        (l & OMAP_DMA_CCR_SEL_SRC_DST_SYNC)) {
                int i = 0;
                u32 sys_cf;

                /* Configure No-Standby */
                l = p->dma_read(OCP_SYSCONFIG, lch);
                sys_cf = l;
                l &= ~DMA_SYSCONFIG_MIDLEMODE_MASK;
                l |= DMA_SYSCONFIG_MIDLEMODE(DMA_IDLEMODE_NO_IDLE);
                p->dma_write(l , OCP_SYSCONFIG, 0);

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

                /* Wait for sDMA FIFO drain */
                l = p->dma_read(CCR, lch);
                while (i < 100 && (l & (OMAP_DMA_CCR_RD_ACTIVE |
                                        OMAP_DMA_CCR_WR_ACTIVE))) {
                        udelay(5);
                        i++;
                        l = p->dma_read(CCR, lch);
                }
                if (i >= 100)
                        pr_err("DMA drain did not complete on lch %d\n", lch);
                /* Restore OCP_SYSCONFIG */
                p->dma_write(sys_cf, OCP_SYSCONFIG, lch);
        } else {
                l &= ~OMAP_DMA_CCR_EN;
                p->dma_write(l, CCR, lch);
        }

        /*
         * Ensure that data transferred by DMA is visible to any access
         * after DMA has been disabled.  This is important for coherent
         * DMA regions.
         */
        mb();

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

        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.
 */
/*
 * 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 between the two reads resulting
 * in incorrect return value.
 */
dma_addr_t omap_get_dma_src_pos(int lch)
{
        dma_addr_t offset = 0;

        if (dma_omap15xx())
                offset = p->dma_read(CPC, lch);
        else
                offset = p->dma_read(CSAC, lch);

        if (IS_DMA_ERRATA(DMA_ERRATA_3_3) && offset == 0)
                offset = p->dma_read(CSAC, lch);

        if (!dma_omap15xx()) {
                /*
                 * CDAC == 0 indicates that the DMA transfer on the channel has
                 * not been started (no data has been transferred so far).
                 * Return the programmed source start address in this case.
                 */
                if (likely(p->dma_read(CDAC, lch)))
                        offset = p->dma_read(CSAC, lch);
                else
                        offset = p->dma_read(CSSA, lch);
        }

        if (dma_omap1())
                offset |= (p->dma_read(CSSA, lch) & 0xFFFF0000);

        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 between the two reads resulting
 * in incorrect return value.
 */
dma_addr_t omap_get_dma_dst_pos(int lch)
{
        dma_addr_t offset = 0;

        if (dma_omap15xx())
                offset = p->dma_read(CPC, lch);
        else
                offset = p->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 (!dma_omap15xx() && offset == 0) {
                offset = p->dma_read(CDAC, lch);
                /*
                 * CDAC == 0 indicates that the DMA transfer on the channel has
                 * not been started (no data has been transferred so far).
                 * Return the programmed destination start address in this case.
                 */
                if (unlikely(!offset))
                        offset = p->dma_read(CDSA, lch);
        }

        if (dma_omap1())
                offset |= (p->dma_read(CDSA, lch) & 0xFFFF0000);

        return offset;
}
EXPORT_SYMBOL(omap_get_dma_dst_pos);

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

int omap_dma_running(void)
{
        int lch;

        if (dma_omap1())
                if (omap_lcd_dma_running())
                        return 1;

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

        return 0;
}

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

#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 = p->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)) {
                pr_warn("Spurious interrupt from DMA channel %d (CSR %04x)\n",
                        ch, csr);
                return 0;
        }
        if (unlikely(csr & OMAP1_DMA_TOUT_IRQ))
                pr_warn("DMA timeout with device %d\n", dma_chan[ch].dev_id);
        if (unlikely(csr & OMAP_DMA_DROP_IRQ))
                pr_warn("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

struct omap_system_dma_plat_info *omap_get_plat_info(void)
{
        return p;
}
EXPORT_SYMBOL_GPL(omap_get_plat_info);

static int omap_system_dma_probe(struct platform_device *pdev)
{
        int ch, ret = 0;
        int dma_irq;
        char irq_name[4];

        p = pdev->dev.platform_data;
        if (!p) {
                dev_err(&pdev->dev,
                        "%s: System DMA initialized without platform data\n",
                        __func__);
                return -EINVAL;
        }

        d                       = p->dma_attr;
        errata                  = p->errata;

        if ((d->dev_caps & RESERVE_CHANNEL) && omap_dma_reserve_channels
                        && (omap_dma_reserve_channels < d->lch_count))
                d->lch_count    = omap_dma_reserve_channels;

        dma_lch_count           = d->lch_count;
        dma_chan_count          = dma_lch_count;
        enable_1510_mode        = d->dev_caps & ENABLE_1510_MODE;

        dma_chan = devm_kcalloc(&pdev->dev, dma_lch_count,
                                sizeof(*dma_chan), GFP_KERNEL);
        if (!dma_chan)
                return -ENOMEM;

        spin_lock_init(&dma_chan_lock);
        for (ch = 0; ch < dma_chan_count; ch++) {
                omap_clear_dma(ch);

                dma_chan[ch].dev_id = -1;
                dma_chan[ch].next_lch = -1;

                if (ch >= 6 && enable_1510_mode)
                        continue;

                if (dma_omap1()) {
                        /*
                         * request_irq() doesn't like dev_id (ie. ch) being
                         * zero, so we have to kludge around this.
                         */
                        sprintf(&irq_name[0], "%d", ch);
                        dma_irq = platform_get_irq_byname(pdev, irq_name);

                        if (dma_irq < 0) {
                                ret = dma_irq;
                                goto exit_dma_irq_fail;
                        }

                        /* INT_DMA_LCD is handled in lcd_dma.c */
                        if (dma_irq == INT_DMA_LCD)
                                continue;

                        ret = request_irq(dma_irq,
                                        omap1_dma_irq_handler, 0, "DMA",
                                        (void *) (ch + 1));
                        if (ret != 0)
                                goto exit_dma_irq_fail;
                }
        }

        /* reserve dma channels 0 and 1 in high security devices on 34xx */
        if (d->dev_caps & HS_CHANNELS_RESERVED) {
                pr_info("Reserving DMA channels 0 and 1 for HS ROM code\n");
                dma_chan[0].dev_id = 0;
                dma_chan[1].dev_id = 1;
        }
        p->show_dma_caps();
        return 0;

exit_dma_irq_fail:
        return ret;
}

static int omap_system_dma_remove(struct platform_device *pdev)
{
        int dma_irq, irq_rel = 0;

        if (dma_omap2plus())
                return 0;

        for ( ; irq_rel < dma_chan_count; irq_rel++) {
                dma_irq = platform_get_irq(pdev, irq_rel);
                free_irq(dma_irq, (void *)(irq_rel + 1));
        }

        return 0;
}

static struct platform_driver omap_system_dma_driver = {
        .probe          = omap_system_dma_probe,
        .remove         = omap_system_dma_remove,
        .driver         = {
                .name   = "omap_dma_system"
        },
};

static int __init omap_system_dma_init(void)
{
        return platform_driver_register(&omap_system_dma_driver);
}
arch_initcall(omap_system_dma_init);

static void __exit omap_system_dma_exit(void)
{
        platform_driver_unregister(&omap_system_dma_driver);
}

MODULE_DESCRIPTION("OMAP SYSTEM DMA DRIVER");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Texas Instruments Inc");

/*
 * Reserve the omap SDMA channels using cmdline bootarg
 * "omap_dma_reserve_ch=". The valid range is 1 to 32
 */
static int __init omap_dma_cmdline_reserve_ch(char *str)
{
        if (get_option(&str, &omap_dma_reserve_channels) != 1)
                omap_dma_reserve_channels = 0;
        return 1;
}

__setup("omap_dma_reserve_ch=", omap_dma_cmdline_reserve_ch);