Merge branches 'for-4.11/upstream-fixes', 'for-4.12/accutouch', 'for-4.12/cp2112...

[mirror_ubuntu-artful-kernel.git] / arch / mips / alchemy / common / dbdma.c

/*
 *
 * BRIEF MODULE DESCRIPTION
 *      The Descriptor Based DMA channel manager that first appeared
 *      on the Au1550.  I started with dma.c, but I think all that is
 *      left is this initial comment :-)
 *
 * Copyright 2004 Embedded Edge, LLC
 *      dan@embeddededge.com
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/syscore_ops.h>
#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/au1xxx_dbdma.h>

/*
 * The Descriptor Based DMA supports up to 16 channels.
 *
 * There are 32 devices defined. We keep an internal structure
 * of devices using these channels, along with additional
 * information.
 *
 * We allocate the descriptors and allow access to them through various
 * functions.  The drivers allocate the data buffers and assign them
 * to the descriptors.
 */
static DEFINE_SPINLOCK(au1xxx_dbdma_spin_lock);

/* I couldn't find a macro that did this... */
#define ALIGN_ADDR(x, a)        ((((u32)(x)) + (a-1)) & ~(a-1))

static dbdma_global_t *dbdma_gptr =
                        (dbdma_global_t *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
static int dbdma_initialized;

static dbdev_tab_t *dbdev_tab;

static dbdev_tab_t au1550_dbdev_tab[] __initdata = {
        /* UARTS */
        { AU1550_DSCR_CMD0_UART0_TX, DEV_FLAGS_OUT, 0, 8, 0x11100004, 0, 0 },
        { AU1550_DSCR_CMD0_UART0_RX, DEV_FLAGS_IN,  0, 8, 0x11100000, 0, 0 },
        { AU1550_DSCR_CMD0_UART3_TX, DEV_FLAGS_OUT, 0, 8, 0x11400004, 0, 0 },
        { AU1550_DSCR_CMD0_UART3_RX, DEV_FLAGS_IN,  0, 8, 0x11400000, 0, 0 },

        /* EXT DMA */
        { AU1550_DSCR_CMD0_DMA_REQ0, 0, 0, 0, 0x00000000, 0, 0 },
        { AU1550_DSCR_CMD0_DMA_REQ1, 0, 0, 0, 0x00000000, 0, 0 },
        { AU1550_DSCR_CMD0_DMA_REQ2, 0, 0, 0, 0x00000000, 0, 0 },
        { AU1550_DSCR_CMD0_DMA_REQ3, 0, 0, 0, 0x00000000, 0, 0 },

        /* USB DEV */
        { AU1550_DSCR_CMD0_USBDEV_RX0, DEV_FLAGS_IN,  4, 8, 0x10200000, 0, 0 },
        { AU1550_DSCR_CMD0_USBDEV_TX0, DEV_FLAGS_OUT, 4, 8, 0x10200004, 0, 0 },
        { AU1550_DSCR_CMD0_USBDEV_TX1, DEV_FLAGS_OUT, 4, 8, 0x10200008, 0, 0 },
        { AU1550_DSCR_CMD0_USBDEV_TX2, DEV_FLAGS_OUT, 4, 8, 0x1020000c, 0, 0 },
        { AU1550_DSCR_CMD0_USBDEV_RX3, DEV_FLAGS_IN,  4, 8, 0x10200010, 0, 0 },
        { AU1550_DSCR_CMD0_USBDEV_RX4, DEV_FLAGS_IN,  4, 8, 0x10200014, 0, 0 },

        /* PSCs */
        { AU1550_DSCR_CMD0_PSC0_TX, DEV_FLAGS_OUT, 0, 0, 0x11a0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC0_RX, DEV_FLAGS_IN,  0, 0, 0x11a0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC1_TX, DEV_FLAGS_OUT, 0, 0, 0x11b0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC1_RX, DEV_FLAGS_IN,  0, 0, 0x11b0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC2_TX, DEV_FLAGS_OUT, 0, 0, 0x10a0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC2_RX, DEV_FLAGS_IN,  0, 0, 0x10a0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC3_TX, DEV_FLAGS_OUT, 0, 0, 0x10b0001c, 0, 0 },
        { AU1550_DSCR_CMD0_PSC3_RX, DEV_FLAGS_IN,  0, 0, 0x10b0001c, 0, 0 },

        { AU1550_DSCR_CMD0_PCI_WRITE,  0, 0, 0, 0x00000000, 0, 0 },  /* PCI */
        { AU1550_DSCR_CMD0_NAND_FLASH, 0, 0, 0, 0x00000000, 0, 0 }, /* NAND */

        /* MAC 0 */
        { AU1550_DSCR_CMD0_MAC0_RX, DEV_FLAGS_IN,  0, 0, 0x00000000, 0, 0 },
        { AU1550_DSCR_CMD0_MAC0_TX, DEV_FLAGS_OUT, 0, 0, 0x00000000, 0, 0 },

        /* MAC 1 */
        { AU1550_DSCR_CMD0_MAC1_RX, DEV_FLAGS_IN,  0, 0, 0x00000000, 0, 0 },
        { AU1550_DSCR_CMD0_MAC1_TX, DEV_FLAGS_OUT, 0, 0, 0x00000000, 0, 0 },

        { DSCR_CMD0_THROTTLE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { DSCR_CMD0_ALWAYS,   DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
};

static dbdev_tab_t au1200_dbdev_tab[] __initdata = {
        { AU1200_DSCR_CMD0_UART0_TX, DEV_FLAGS_OUT, 0, 8, 0x11100004, 0, 0 },
        { AU1200_DSCR_CMD0_UART0_RX, DEV_FLAGS_IN,  0, 8, 0x11100000, 0, 0 },
        { AU1200_DSCR_CMD0_UART1_TX, DEV_FLAGS_OUT, 0, 8, 0x11200004, 0, 0 },
        { AU1200_DSCR_CMD0_UART1_RX, DEV_FLAGS_IN,  0, 8, 0x11200000, 0, 0 },

        { AU1200_DSCR_CMD0_DMA_REQ0, 0, 0, 0, 0x00000000, 0, 0 },
        { AU1200_DSCR_CMD0_DMA_REQ1, 0, 0, 0, 0x00000000, 0, 0 },

        { AU1200_DSCR_CMD0_MAE_BE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { AU1200_DSCR_CMD0_MAE_FE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { AU1200_DSCR_CMD0_MAE_BOTH, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { AU1200_DSCR_CMD0_LCD, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },

        { AU1200_DSCR_CMD0_SDMS_TX0, DEV_FLAGS_OUT, 4, 8, 0x10600000, 0, 0 },
        { AU1200_DSCR_CMD0_SDMS_RX0, DEV_FLAGS_IN,  4, 8, 0x10600004, 0, 0 },
        { AU1200_DSCR_CMD0_SDMS_TX1, DEV_FLAGS_OUT, 4, 8, 0x10680000, 0, 0 },
        { AU1200_DSCR_CMD0_SDMS_RX1, DEV_FLAGS_IN,  4, 8, 0x10680004, 0, 0 },

        { AU1200_DSCR_CMD0_AES_RX, DEV_FLAGS_IN , 4, 32, 0x10300008, 0, 0 },
        { AU1200_DSCR_CMD0_AES_TX, DEV_FLAGS_OUT, 4, 32, 0x10300004, 0, 0 },

        { AU1200_DSCR_CMD0_PSC0_TX,   DEV_FLAGS_OUT, 0, 16, 0x11a0001c, 0, 0 },
        { AU1200_DSCR_CMD0_PSC0_RX,   DEV_FLAGS_IN,  0, 16, 0x11a0001c, 0, 0 },
        { AU1200_DSCR_CMD0_PSC0_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { AU1200_DSCR_CMD0_PSC1_TX,   DEV_FLAGS_OUT, 0, 16, 0x11b0001c, 0, 0 },
        { AU1200_DSCR_CMD0_PSC1_RX,   DEV_FLAGS_IN,  0, 16, 0x11b0001c, 0, 0 },
        { AU1200_DSCR_CMD0_PSC1_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },

        { AU1200_DSCR_CMD0_CIM_RXA,  DEV_FLAGS_IN, 0, 32, 0x14004020, 0, 0 },
        { AU1200_DSCR_CMD0_CIM_RXB,  DEV_FLAGS_IN, 0, 32, 0x14004040, 0, 0 },
        { AU1200_DSCR_CMD0_CIM_RXC,  DEV_FLAGS_IN, 0, 32, 0x14004060, 0, 0 },
        { AU1200_DSCR_CMD0_CIM_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },

        { AU1200_DSCR_CMD0_NAND_FLASH, DEV_FLAGS_IN, 0, 0, 0x00000000, 0, 0 },

        { DSCR_CMD0_THROTTLE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { DSCR_CMD0_ALWAYS,   DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
};

static dbdev_tab_t au1300_dbdev_tab[] __initdata = {
        { AU1300_DSCR_CMD0_UART0_TX, DEV_FLAGS_OUT, 0, 8,  0x10100004, 0, 0 },
        { AU1300_DSCR_CMD0_UART0_RX, DEV_FLAGS_IN,  0, 8,  0x10100000, 0, 0 },
        { AU1300_DSCR_CMD0_UART1_TX, DEV_FLAGS_OUT, 0, 8,  0x10101004, 0, 0 },
        { AU1300_DSCR_CMD0_UART1_RX, DEV_FLAGS_IN,  0, 8,  0x10101000, 0, 0 },
        { AU1300_DSCR_CMD0_UART2_TX, DEV_FLAGS_OUT, 0, 8,  0x10102004, 0, 0 },
        { AU1300_DSCR_CMD0_UART2_RX, DEV_FLAGS_IN,  0, 8,  0x10102000, 0, 0 },
        { AU1300_DSCR_CMD0_UART3_TX, DEV_FLAGS_OUT, 0, 8,  0x10103004, 0, 0 },
        { AU1300_DSCR_CMD0_UART3_RX, DEV_FLAGS_IN,  0, 8,  0x10103000, 0, 0 },

        { AU1300_DSCR_CMD0_SDMS_TX0, DEV_FLAGS_OUT, 4, 8,  0x10600000, 0, 0 },
        { AU1300_DSCR_CMD0_SDMS_RX0, DEV_FLAGS_IN,  4, 8,  0x10600004, 0, 0 },
        { AU1300_DSCR_CMD0_SDMS_TX1, DEV_FLAGS_OUT, 8, 8,  0x10601000, 0, 0 },
        { AU1300_DSCR_CMD0_SDMS_RX1, DEV_FLAGS_IN,  8, 8,  0x10601004, 0, 0 },

        { AU1300_DSCR_CMD0_AES_RX, DEV_FLAGS_IN ,   4, 32, 0x10300008, 0, 0 },
        { AU1300_DSCR_CMD0_AES_TX, DEV_FLAGS_OUT,   4, 32, 0x10300004, 0, 0 },

        { AU1300_DSCR_CMD0_PSC0_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0001c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC0_RX, DEV_FLAGS_IN,   0, 16, 0x10a0001c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC1_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0101c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC1_RX, DEV_FLAGS_IN,   0, 16, 0x10a0101c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC2_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0201c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC2_RX, DEV_FLAGS_IN,   0, 16, 0x10a0201c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC3_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0301c, 0, 0 },
        { AU1300_DSCR_CMD0_PSC3_RX, DEV_FLAGS_IN,   0, 16, 0x10a0301c, 0, 0 },

        { AU1300_DSCR_CMD0_LCD, DEV_FLAGS_ANYUSE,   0, 0,  0x00000000, 0, 0 },
        { AU1300_DSCR_CMD0_NAND_FLASH, DEV_FLAGS_IN, 0, 0, 0x00000000, 0, 0 },

        { AU1300_DSCR_CMD0_SDMS_TX2, DEV_FLAGS_OUT, 4, 8,  0x10602000, 0, 0 },
        { AU1300_DSCR_CMD0_SDMS_RX2, DEV_FLAGS_IN,  4, 8,  0x10602004, 0, 0 },

        { AU1300_DSCR_CMD0_CIM_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },

        { AU1300_DSCR_CMD0_UDMA, DEV_FLAGS_ANYUSE,  0, 32, 0x14001810, 0, 0 },

        { AU1300_DSCR_CMD0_DMA_REQ0, 0, 0, 0, 0x00000000, 0, 0 },
        { AU1300_DSCR_CMD0_DMA_REQ1, 0, 0, 0, 0x00000000, 0, 0 },

        { DSCR_CMD0_THROTTLE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
        { DSCR_CMD0_ALWAYS,   DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
};

/* 32 predefined plus 32 custom */
#define DBDEV_TAB_SIZE          64

static chan_tab_t *chan_tab_ptr[NUM_DBDMA_CHANS];

static dbdev_tab_t *find_dbdev_id(u32 id)
{
        int i;
        dbdev_tab_t *p;
        for (i = 0; i < DBDEV_TAB_SIZE; ++i) {
                p = &dbdev_tab[i];
                if (p->dev_id == id)
                        return p;
        }
        return NULL;
}

void *au1xxx_ddma_get_nextptr_virt(au1x_ddma_desc_t *dp)
{
        return phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
}
EXPORT_SYMBOL(au1xxx_ddma_get_nextptr_virt);

u32 au1xxx_ddma_add_device(dbdev_tab_t *dev)
{
        u32 ret = 0;
        dbdev_tab_t *p;
        static u16 new_id = 0x1000;

        p = find_dbdev_id(~0);
        if (NULL != p) {
                memcpy(p, dev, sizeof(dbdev_tab_t));
                p->dev_id = DSCR_DEV2CUSTOM_ID(new_id, dev->dev_id);
                ret = p->dev_id;
                new_id++;
#if 0
                printk(KERN_DEBUG "add_device: id:%x flags:%x padd:%x\n",
                                  p->dev_id, p->dev_flags, p->dev_physaddr);
#endif
        }

        return ret;
}
EXPORT_SYMBOL(au1xxx_ddma_add_device);

void au1xxx_ddma_del_device(u32 devid)
{
        dbdev_tab_t *p = find_dbdev_id(devid);

        if (p != NULL) {
                memset(p, 0, sizeof(dbdev_tab_t));
                p->dev_id = ~0;
        }
}
EXPORT_SYMBOL(au1xxx_ddma_del_device);

/* Allocate a channel and return a non-zero descriptor if successful. */
u32 au1xxx_dbdma_chan_alloc(u32 srcid, u32 destid,
       void (*callback)(int, void *), void *callparam)
{
        unsigned long   flags;
        u32             used, chan;
        u32             dcp;
        int             i;
        dbdev_tab_t     *stp, *dtp;
        chan_tab_t      *ctp;
        au1x_dma_chan_t *cp;

        /*
         * We do the initialization on the first channel allocation.
         * We have to wait because of the interrupt handler initialization
         * which can't be done successfully during board set up.
         */
        if (!dbdma_initialized)
                return 0;

        stp = find_dbdev_id(srcid);
        if (stp == NULL)
                return 0;
        dtp = find_dbdev_id(destid);
        if (dtp == NULL)
                return 0;

        used = 0;

        /* Check to see if we can get both channels. */
        spin_lock_irqsave(&au1xxx_dbdma_spin_lock, flags);
        if (!(stp->dev_flags & DEV_FLAGS_INUSE) ||
             (stp->dev_flags & DEV_FLAGS_ANYUSE)) {
                /* Got source */
                stp->dev_flags |= DEV_FLAGS_INUSE;
                if (!(dtp->dev_flags & DEV_FLAGS_INUSE) ||
                     (dtp->dev_flags & DEV_FLAGS_ANYUSE)) {
                        /* Got destination */
                        dtp->dev_flags |= DEV_FLAGS_INUSE;
                } else {
                        /* Can't get dest.  Release src. */
                        stp->dev_flags &= ~DEV_FLAGS_INUSE;
                        used++;
                }
        } else
                used++;
        spin_unlock_irqrestore(&au1xxx_dbdma_spin_lock, flags);

        if (used)
                return 0;

        /* Let's see if we can allocate a channel for it. */
        ctp = NULL;
        chan = 0;
        spin_lock_irqsave(&au1xxx_dbdma_spin_lock, flags);
        for (i = 0; i < NUM_DBDMA_CHANS; i++)
                if (chan_tab_ptr[i] == NULL) {
                        /*
                         * If kmalloc fails, it is caught below same
                         * as a channel not available.
                         */
                        ctp = kmalloc(sizeof(chan_tab_t), GFP_ATOMIC);
                        chan_tab_ptr[i] = ctp;
                        break;
                }
        spin_unlock_irqrestore(&au1xxx_dbdma_spin_lock, flags);

        if (ctp != NULL) {
                memset(ctp, 0, sizeof(chan_tab_t));
                ctp->chan_index = chan = i;
                dcp = KSEG1ADDR(AU1550_DBDMA_PHYS_ADDR);
                dcp += (0x0100 * chan);
                ctp->chan_ptr = (au1x_dma_chan_t *)dcp;
                cp = (au1x_dma_chan_t *)dcp;
                ctp->chan_src = stp;
                ctp->chan_dest = dtp;
                ctp->chan_callback = callback;
                ctp->chan_callparam = callparam;

                /* Initialize channel configuration. */
                i = 0;
                if (stp->dev_intlevel)
                        i |= DDMA_CFG_SED;
                if (stp->dev_intpolarity)
                        i |= DDMA_CFG_SP;
                if (dtp->dev_intlevel)
                        i |= DDMA_CFG_DED;
                if (dtp->dev_intpolarity)
                        i |= DDMA_CFG_DP;
                if ((stp->dev_flags & DEV_FLAGS_SYNC) ||
                        (dtp->dev_flags & DEV_FLAGS_SYNC))
                                i |= DDMA_CFG_SYNC;
                cp->ddma_cfg = i;
                wmb(); /* drain writebuffer */

                /*
                 * Return a non-zero value that can be used to find the channel
                 * information in subsequent operations.
                 */
                return (u32)(&chan_tab_ptr[chan]);
        }

        /* Release devices */
        stp->dev_flags &= ~DEV_FLAGS_INUSE;
        dtp->dev_flags &= ~DEV_FLAGS_INUSE;

        return 0;
}
EXPORT_SYMBOL(au1xxx_dbdma_chan_alloc);

/*
 * Set the device width if source or destination is a FIFO.
 * Should be 8, 16, or 32 bits.
 */
u32 au1xxx_dbdma_set_devwidth(u32 chanid, int bits)
{
        u32             rv;
        chan_tab_t      *ctp;
        dbdev_tab_t     *stp, *dtp;

        ctp = *((chan_tab_t **)chanid);
        stp = ctp->chan_src;
        dtp = ctp->chan_dest;
        rv = 0;

        if (stp->dev_flags & DEV_FLAGS_IN) {    /* Source in fifo */
                rv = stp->dev_devwidth;
                stp->dev_devwidth = bits;
        }
        if (dtp->dev_flags & DEV_FLAGS_OUT) {   /* Destination out fifo */
                rv = dtp->dev_devwidth;
                dtp->dev_devwidth = bits;
        }

        return rv;
}
EXPORT_SYMBOL(au1xxx_dbdma_set_devwidth);

/* Allocate a descriptor ring, initializing as much as possible. */
u32 au1xxx_dbdma_ring_alloc(u32 chanid, int entries)
{
        int                     i;
        u32                     desc_base, srcid, destid;
        u32                     cmd0, cmd1, src1, dest1;
        u32                     src0, dest0;
        chan_tab_t              *ctp;
        dbdev_tab_t             *stp, *dtp;
        au1x_ddma_desc_t        *dp;

        /*
         * I guess we could check this to be within the
         * range of the table......
         */
        ctp = *((chan_tab_t **)chanid);
        stp = ctp->chan_src;
        dtp = ctp->chan_dest;

        /*
         * The descriptors must be 32-byte aligned.  There is a
         * possibility the allocation will give us such an address,
         * and if we try that first we are likely to not waste larger
         * slabs of memory.
         */
        desc_base = (u32)kmalloc(entries * sizeof(au1x_ddma_desc_t),
                                 GFP_KERNEL|GFP_DMA);
        if (desc_base == 0)
                return 0;

        if (desc_base & 0x1f) {
                /*
                 * Lost....do it again, allocate extra, and round
                 * the address base.
                 */
                kfree((const void *)desc_base);
                i = entries * sizeof(au1x_ddma_desc_t);
                i += (sizeof(au1x_ddma_desc_t) - 1);
                desc_base = (u32)kmalloc(i, GFP_KERNEL|GFP_DMA);
                if (desc_base == 0)
                        return 0;

                ctp->cdb_membase = desc_base;
                desc_base = ALIGN_ADDR(desc_base, sizeof(au1x_ddma_desc_t));
        } else
                ctp->cdb_membase = desc_base;

        dp = (au1x_ddma_desc_t *)desc_base;

        /* Keep track of the base descriptor. */
        ctp->chan_desc_base = dp;

        /* Initialize the rings with as much information as we know. */
        srcid = stp->dev_id;
        destid = dtp->dev_id;

        cmd0 = cmd1 = src1 = dest1 = 0;
        src0 = dest0 = 0;

        cmd0 |= DSCR_CMD0_SID(srcid);
        cmd0 |= DSCR_CMD0_DID(destid);
        cmd0 |= DSCR_CMD0_IE | DSCR_CMD0_CV;
        cmd0 |= DSCR_CMD0_ST(DSCR_CMD0_ST_NOCHANGE);

        /* Is it mem to mem transfer? */
        if (((DSCR_CUSTOM2DEV_ID(srcid) == DSCR_CMD0_THROTTLE) ||
             (DSCR_CUSTOM2DEV_ID(srcid) == DSCR_CMD0_ALWAYS)) &&
            ((DSCR_CUSTOM2DEV_ID(destid) == DSCR_CMD0_THROTTLE) ||
             (DSCR_CUSTOM2DEV_ID(destid) == DSCR_CMD0_ALWAYS)))
                cmd0 |= DSCR_CMD0_MEM;

        switch (stp->dev_devwidth) {
        case 8:
                cmd0 |= DSCR_CMD0_SW(DSCR_CMD0_BYTE);
                break;
        case 16:
                cmd0 |= DSCR_CMD0_SW(DSCR_CMD0_HALFWORD);
                break;
        case 32:
        default:
                cmd0 |= DSCR_CMD0_SW(DSCR_CMD0_WORD);
                break;
        }

        switch (dtp->dev_devwidth) {
        case 8:
                cmd0 |= DSCR_CMD0_DW(DSCR_CMD0_BYTE);
                break;
        case 16:
                cmd0 |= DSCR_CMD0_DW(DSCR_CMD0_HALFWORD);
                break;
        case 32:
        default:
                cmd0 |= DSCR_CMD0_DW(DSCR_CMD0_WORD);
                break;
        }

        /*
         * If the device is marked as an in/out FIFO, ensure it is
         * set non-coherent.
         */
        if (stp->dev_flags & DEV_FLAGS_IN)
                cmd0 |= DSCR_CMD0_SN;           /* Source in FIFO */
        if (dtp->dev_flags & DEV_FLAGS_OUT)
                cmd0 |= DSCR_CMD0_DN;           /* Destination out FIFO */

        /*
         * Set up source1.  For now, assume no stride and increment.
         * A channel attribute update can change this later.
         */
        switch (stp->dev_tsize) {
        case 1:
                src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE1);
                break;
        case 2:
                src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE2);
                break;
        case 4:
                src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE4);
                break;
        case 8:
        default:
                src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE8);
                break;
        }

        /* If source input is FIFO, set static address. */
        if (stp->dev_flags & DEV_FLAGS_IN) {
                if (stp->dev_flags & DEV_FLAGS_BURSTABLE)
                        src1 |= DSCR_SRC1_SAM(DSCR_xAM_BURST);
                else
                        src1 |= DSCR_SRC1_SAM(DSCR_xAM_STATIC);
        }

        if (stp->dev_physaddr)
                src0 = stp->dev_physaddr;

        /*
         * Set up dest1.  For now, assume no stride and increment.
         * A channel attribute update can change this later.
         */
        switch (dtp->dev_tsize) {
        case 1:
                dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE1);
                break;
        case 2:
                dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE2);
                break;
        case 4:
                dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE4);
                break;
        case 8:
        default:
                dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE8);
                break;
        }

        /* If destination output is FIFO, set static address. */
        if (dtp->dev_flags & DEV_FLAGS_OUT) {
                if (dtp->dev_flags & DEV_FLAGS_BURSTABLE)
                        dest1 |= DSCR_DEST1_DAM(DSCR_xAM_BURST);
                else
                        dest1 |= DSCR_DEST1_DAM(DSCR_xAM_STATIC);
        }

        if (dtp->dev_physaddr)
                dest0 = dtp->dev_physaddr;

#if 0
                printk(KERN_DEBUG "did:%x sid:%x cmd0:%x cmd1:%x source0:%x "
                                  "source1:%x dest0:%x dest1:%x\n",
                                  dtp->dev_id, stp->dev_id, cmd0, cmd1, src0,
                                  src1, dest0, dest1);
#endif
        for (i = 0; i < entries; i++) {
                dp->dscr_cmd0 = cmd0;
                dp->dscr_cmd1 = cmd1;
                dp->dscr_source0 = src0;
                dp->dscr_source1 = src1;
                dp->dscr_dest0 = dest0;
                dp->dscr_dest1 = dest1;
                dp->dscr_stat = 0;
                dp->sw_context = 0;
                dp->sw_status = 0;
                dp->dscr_nxtptr = DSCR_NXTPTR(virt_to_phys(dp + 1));
                dp++;
        }

        /* Make last descrptor point to the first. */
        dp--;
        dp->dscr_nxtptr = DSCR_NXTPTR(virt_to_phys(ctp->chan_desc_base));
        ctp->get_ptr = ctp->put_ptr = ctp->cur_ptr = ctp->chan_desc_base;

        return (u32)ctp->chan_desc_base;
}
EXPORT_SYMBOL(au1xxx_dbdma_ring_alloc);

/*
 * Put a source buffer into the DMA ring.
 * This updates the source pointer and byte count.  Normally used
 * for memory to fifo transfers.
 */
u32 au1xxx_dbdma_put_source(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
{
        chan_tab_t              *ctp;
        au1x_ddma_desc_t        *dp;

        /*
         * I guess we could check this to be within the
         * range of the table......
         */
        ctp = *(chan_tab_t **)chanid;

        /*
         * We should have multiple callers for a particular channel,
         * an interrupt doesn't affect this pointer nor the descriptor,
         * so no locking should be needed.
         */
        dp = ctp->put_ptr;

        /*
         * If the descriptor is valid, we are way ahead of the DMA
         * engine, so just return an error condition.
         */
        if (dp->dscr_cmd0 & DSCR_CMD0_V)
                return 0;

        /* Load up buffer address and byte count. */
        dp->dscr_source0 = buf & ~0UL;
        dp->dscr_cmd1 = nbytes;
        /* Check flags */
        if (flags & DDMA_FLAGS_IE)
                dp->dscr_cmd0 |= DSCR_CMD0_IE;
        if (flags & DDMA_FLAGS_NOIE)
                dp->dscr_cmd0 &= ~DSCR_CMD0_IE;

        /*
         * There is an errata on the Au1200/Au1550 parts that could result
         * in "stale" data being DMA'ed. It has to do with the snoop logic on
         * the cache eviction buffer.  DMA_NONCOHERENT is on by default for
         * these parts. If it is fixed in the future, these dma_cache_inv will
         * just be nothing more than empty macros. See io.h.
         */
        dma_cache_wback_inv((unsigned long)buf, nbytes);
        dp->dscr_cmd0 |= DSCR_CMD0_V;   /* Let it rip */
        wmb(); /* drain writebuffer */
        dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
        ctp->chan_ptr->ddma_dbell = 0;

        /* Get next descriptor pointer. */
        ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));

        /* Return something non-zero. */
        return nbytes;
}
EXPORT_SYMBOL(au1xxx_dbdma_put_source);

/* Put a destination buffer into the DMA ring.
 * This updates the destination pointer and byte count.  Normally used
 * to place an empty buffer into the ring for fifo to memory transfers.
 */
u32 au1xxx_dbdma_put_dest(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
{
        chan_tab_t              *ctp;
        au1x_ddma_desc_t        *dp;

        /* I guess we could check this to be within the
         * range of the table......
         */
        ctp = *((chan_tab_t **)chanid);

        /* We should have multiple callers for a particular channel,
         * an interrupt doesn't affect this pointer nor the descriptor,
         * so no locking should be needed.
         */
        dp = ctp->put_ptr;

        /* If the descriptor is valid, we are way ahead of the DMA
         * engine, so just return an error condition.
         */
        if (dp->dscr_cmd0 & DSCR_CMD0_V)
                return 0;

        /* Load up buffer address and byte count */

        /* Check flags  */
        if (flags & DDMA_FLAGS_IE)
                dp->dscr_cmd0 |= DSCR_CMD0_IE;
        if (flags & DDMA_FLAGS_NOIE)
                dp->dscr_cmd0 &= ~DSCR_CMD0_IE;

        dp->dscr_dest0 = buf & ~0UL;
        dp->dscr_cmd1 = nbytes;
#if 0
        printk(KERN_DEBUG "cmd0:%x cmd1:%x source0:%x source1:%x dest0:%x dest1:%x\n",
                          dp->dscr_cmd0, dp->dscr_cmd1, dp->dscr_source0,
                          dp->dscr_source1, dp->dscr_dest0, dp->dscr_dest1);
#endif
        /*
         * There is an errata on the Au1200/Au1550 parts that could result in
         * "stale" data being DMA'ed. It has to do with the snoop logic on the
         * cache eviction buffer.  DMA_NONCOHERENT is on by default for these
         * parts. If it is fixed in the future, these dma_cache_inv will just
         * be nothing more than empty macros. See io.h.
         */
        dma_cache_inv((unsigned long)buf, nbytes);
        dp->dscr_cmd0 |= DSCR_CMD0_V;   /* Let it rip */
        wmb(); /* drain writebuffer */
        dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
        ctp->chan_ptr->ddma_dbell = 0;

        /* Get next descriptor pointer. */
        ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));

        /* Return something non-zero. */
        return nbytes;
}
EXPORT_SYMBOL(au1xxx_dbdma_put_dest);

/*
 * Get a destination buffer into the DMA ring.
 * Normally used to get a full buffer from the ring during fifo
 * to memory transfers.  This does not set the valid bit, you will
 * have to put another destination buffer to keep the DMA going.
 */
u32 au1xxx_dbdma_get_dest(u32 chanid, void **buf, int *nbytes)
{
        chan_tab_t              *ctp;
        au1x_ddma_desc_t        *dp;
        u32                     rv;

        /*
         * I guess we could check this to be within the
         * range of the table......
         */
        ctp = *((chan_tab_t **)chanid);

        /*
         * We should have multiple callers for a particular channel,
         * an interrupt doesn't affect this pointer nor the descriptor,
         * so no locking should be needed.
         */
        dp = ctp->get_ptr;

        /*
         * If the descriptor is valid, we are way ahead of the DMA
         * engine, so just return an error condition.
         */
        if (dp->dscr_cmd0 & DSCR_CMD0_V)
                return 0;

        /* Return buffer address and byte count. */
        *buf = (void *)(phys_to_virt(dp->dscr_dest0));
        *nbytes = dp->dscr_cmd1;
        rv = dp->dscr_stat;

        /* Get next descriptor pointer. */
        ctp->get_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));

        /* Return something non-zero. */
        return rv;
}
EXPORT_SYMBOL_GPL(au1xxx_dbdma_get_dest);

void au1xxx_dbdma_stop(u32 chanid)
{
        chan_tab_t      *ctp;
        au1x_dma_chan_t *cp;
        int halt_timeout = 0;

        ctp = *((chan_tab_t **)chanid);

        cp = ctp->chan_ptr;
        cp->ddma_cfg &= ~DDMA_CFG_EN;   /* Disable channel */
        wmb(); /* drain writebuffer */
        while (!(cp->ddma_stat & DDMA_STAT_H)) {
                udelay(1);
                halt_timeout++;
                if (halt_timeout > 100) {
                        printk(KERN_WARNING "warning: DMA channel won't halt\n");
                        break;
                }
        }
        /* clear current desc valid and doorbell */
        cp->ddma_stat |= (DDMA_STAT_DB | DDMA_STAT_V);
        wmb(); /* drain writebuffer */
}
EXPORT_SYMBOL(au1xxx_dbdma_stop);

/*
 * Start using the current descriptor pointer.  If the DBDMA encounters
 * a non-valid descriptor, it will stop.  In this case, we can just
 * continue by adding a buffer to the list and starting again.
 */
void au1xxx_dbdma_start(u32 chanid)
{
        chan_tab_t      *ctp;
        au1x_dma_chan_t *cp;

        ctp = *((chan_tab_t **)chanid);
        cp = ctp->chan_ptr;
        cp->ddma_desptr = virt_to_phys(ctp->cur_ptr);
        cp->ddma_cfg |= DDMA_CFG_EN;    /* Enable channel */
        wmb(); /* drain writebuffer */
        cp->ddma_dbell = 0;
        wmb(); /* drain writebuffer */
}
EXPORT_SYMBOL(au1xxx_dbdma_start);

void au1xxx_dbdma_reset(u32 chanid)
{
        chan_tab_t              *ctp;
        au1x_ddma_desc_t        *dp;

        au1xxx_dbdma_stop(chanid);

        ctp = *((chan_tab_t **)chanid);
        ctp->get_ptr = ctp->put_ptr = ctp->cur_ptr = ctp->chan_desc_base;

        /* Run through the descriptors and reset the valid indicator. */
        dp = ctp->chan_desc_base;

        do {
                dp->dscr_cmd0 &= ~DSCR_CMD0_V;
                /*
                 * Reset our software status -- this is used to determine
                 * if a descriptor is in use by upper level software. Since
                 * posting can reset 'V' bit.
                 */
                dp->sw_status = 0;
                dp = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
        } while (dp != ctp->chan_desc_base);
}
EXPORT_SYMBOL(au1xxx_dbdma_reset);

u32 au1xxx_get_dma_residue(u32 chanid)
{
        chan_tab_t      *ctp;
        au1x_dma_chan_t *cp;
        u32             rv;

        ctp = *((chan_tab_t **)chanid);
        cp = ctp->chan_ptr;

        /* This is only valid if the channel is stopped. */
        rv = cp->ddma_bytecnt;
        wmb(); /* drain writebuffer */

        return rv;
}
EXPORT_SYMBOL_GPL(au1xxx_get_dma_residue);

void au1xxx_dbdma_chan_free(u32 chanid)
{
        chan_tab_t      *ctp;
        dbdev_tab_t     *stp, *dtp;

        ctp = *((chan_tab_t **)chanid);
        stp = ctp->chan_src;
        dtp = ctp->chan_dest;

        au1xxx_dbdma_stop(chanid);

        kfree((void *)ctp->cdb_membase);

        stp->dev_flags &= ~DEV_FLAGS_INUSE;
        dtp->dev_flags &= ~DEV_FLAGS_INUSE;
        chan_tab_ptr[ctp->chan_index] = NULL;

        kfree(ctp);
}
EXPORT_SYMBOL(au1xxx_dbdma_chan_free);

static irqreturn_t dbdma_interrupt(int irq, void *dev_id)
{
        u32 intstat;
        u32 chan_index;
        chan_tab_t              *ctp;
        au1x_ddma_desc_t        *dp;
        au1x_dma_chan_t *cp;

        intstat = dbdma_gptr->ddma_intstat;
        wmb(); /* drain writebuffer */
        chan_index = __ffs(intstat);

        ctp = chan_tab_ptr[chan_index];
        cp = ctp->chan_ptr;
        dp = ctp->cur_ptr;

        /* Reset interrupt. */
        cp->ddma_irq = 0;
        wmb(); /* drain writebuffer */

        if (ctp->chan_callback)
                ctp->chan_callback(irq, ctp->chan_callparam);

        ctp->cur_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
        return IRQ_RETVAL(1);
}

void au1xxx_dbdma_dump(u32 chanid)
{
        chan_tab_t       *ctp;
        au1x_ddma_desc_t *dp;
        dbdev_tab_t      *stp, *dtp;
        au1x_dma_chan_t  *cp;
        u32 i            = 0;

        ctp = *((chan_tab_t **)chanid);
        stp = ctp->chan_src;
        dtp = ctp->chan_dest;
        cp = ctp->chan_ptr;

        printk(KERN_DEBUG "Chan %x, stp %x (dev %d)  dtp %x (dev %d)\n",
                          (u32)ctp, (u32)stp, stp - dbdev_tab, (u32)dtp,
                          dtp - dbdev_tab);
        printk(KERN_DEBUG "desc base %x, get %x, put %x, cur %x\n",
                          (u32)(ctp->chan_desc_base), (u32)(ctp->get_ptr),
                          (u32)(ctp->put_ptr), (u32)(ctp->cur_ptr));

        printk(KERN_DEBUG "dbdma chan %x\n", (u32)cp);
        printk(KERN_DEBUG "cfg %08x, desptr %08x, statptr %08x\n",
                          cp->ddma_cfg, cp->ddma_desptr, cp->ddma_statptr);
        printk(KERN_DEBUG "dbell %08x, irq %08x, stat %08x, bytecnt %08x\n",
                          cp->ddma_dbell, cp->ddma_irq, cp->ddma_stat,
                          cp->ddma_bytecnt);

        /* Run through the descriptors */
        dp = ctp->chan_desc_base;

        do {
                printk(KERN_DEBUG "Dp[%d]= %08x, cmd0 %08x, cmd1 %08x\n",
                                  i++, (u32)dp, dp->dscr_cmd0, dp->dscr_cmd1);
                printk(KERN_DEBUG "src0 %08x, src1 %08x, dest0 %08x, dest1 %08x\n",
                                  dp->dscr_source0, dp->dscr_source1,
                                  dp->dscr_dest0, dp->dscr_dest1);
                printk(KERN_DEBUG "stat %08x, nxtptr %08x\n",
                                  dp->dscr_stat, dp->dscr_nxtptr);
                dp = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
        } while (dp != ctp->chan_desc_base);
}

/* Put a descriptor into the DMA ring.
 * This updates the source/destination pointers and byte count.
 */
u32 au1xxx_dbdma_put_dscr(u32 chanid, au1x_ddma_desc_t *dscr)
{
        chan_tab_t *ctp;
        au1x_ddma_desc_t *dp;
        u32 nbytes = 0;

        /*
         * I guess we could check this to be within the
         * range of the table......
         */
        ctp = *((chan_tab_t **)chanid);

        /*
         * We should have multiple callers for a particular channel,
         * an interrupt doesn't affect this pointer nor the descriptor,
         * so no locking should be needed.
         */
        dp = ctp->put_ptr;

        /*
         * If the descriptor is valid, we are way ahead of the DMA
         * engine, so just return an error condition.
         */
        if (dp->dscr_cmd0 & DSCR_CMD0_V)
                return 0;

        /* Load up buffer addresses and byte count. */
        dp->dscr_dest0 = dscr->dscr_dest0;
        dp->dscr_source0 = dscr->dscr_source0;
        dp->dscr_dest1 = dscr->dscr_dest1;
        dp->dscr_source1 = dscr->dscr_source1;
        dp->dscr_cmd1 = dscr->dscr_cmd1;
        nbytes = dscr->dscr_cmd1;
        /* Allow the caller to specify if an interrupt is generated */
        dp->dscr_cmd0 &= ~DSCR_CMD0_IE;
        dp->dscr_cmd0 |= dscr->dscr_cmd0 | DSCR_CMD0_V;
        ctp->chan_ptr->ddma_dbell = 0;

        /* Get next descriptor pointer. */
        ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));

        /* Return something non-zero. */
        return nbytes;
}


static unsigned long alchemy_dbdma_pm_data[NUM_DBDMA_CHANS + 1][6];

static int alchemy_dbdma_suspend(void)
{
        int i;
        void __iomem *addr;

        addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
        alchemy_dbdma_pm_data[0][0] = __raw_readl(addr + 0x00);
        alchemy_dbdma_pm_data[0][1] = __raw_readl(addr + 0x04);
        alchemy_dbdma_pm_data[0][2] = __raw_readl(addr + 0x08);
        alchemy_dbdma_pm_data[0][3] = __raw_readl(addr + 0x0c);

        /* save channel configurations */
        addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_PHYS_ADDR);
        for (i = 1; i <= NUM_DBDMA_CHANS; i++) {
                alchemy_dbdma_pm_data[i][0] = __raw_readl(addr + 0x00);
                alchemy_dbdma_pm_data[i][1] = __raw_readl(addr + 0x04);
                alchemy_dbdma_pm_data[i][2] = __raw_readl(addr + 0x08);
                alchemy_dbdma_pm_data[i][3] = __raw_readl(addr + 0x0c);
                alchemy_dbdma_pm_data[i][4] = __raw_readl(addr + 0x10);
                alchemy_dbdma_pm_data[i][5] = __raw_readl(addr + 0x14);

                /* halt channel */
                __raw_writel(alchemy_dbdma_pm_data[i][0] & ~1, addr + 0x00);
                wmb();
                while (!(__raw_readl(addr + 0x14) & 1))
                        wmb();

                addr += 0x100;  /* next channel base */
        }
        /* disable channel interrupts */
        addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
        __raw_writel(0, addr + 0x0c);
        wmb();

        return 0;
}

static void alchemy_dbdma_resume(void)
{
        int i;
        void __iomem *addr;

        addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
        __raw_writel(alchemy_dbdma_pm_data[0][0], addr + 0x00);
        __raw_writel(alchemy_dbdma_pm_data[0][1], addr + 0x04);
        __raw_writel(alchemy_dbdma_pm_data[0][2], addr + 0x08);
        __raw_writel(alchemy_dbdma_pm_data[0][3], addr + 0x0c);

        /* restore channel configurations */
        addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_PHYS_ADDR);
        for (i = 1; i <= NUM_DBDMA_CHANS; i++) {
                __raw_writel(alchemy_dbdma_pm_data[i][0], addr + 0x00);
                __raw_writel(alchemy_dbdma_pm_data[i][1], addr + 0x04);
                __raw_writel(alchemy_dbdma_pm_data[i][2], addr + 0x08);
                __raw_writel(alchemy_dbdma_pm_data[i][3], addr + 0x0c);
                __raw_writel(alchemy_dbdma_pm_data[i][4], addr + 0x10);
                __raw_writel(alchemy_dbdma_pm_data[i][5], addr + 0x14);
                wmb();
                addr += 0x100;  /* next channel base */
        }
}

static struct syscore_ops alchemy_dbdma_syscore_ops = {
        .suspend        = alchemy_dbdma_suspend,
        .resume         = alchemy_dbdma_resume,
};

static int __init dbdma_setup(unsigned int irq, dbdev_tab_t *idtable)
{
        int ret;

        dbdev_tab = kzalloc(sizeof(dbdev_tab_t) * DBDEV_TAB_SIZE, GFP_KERNEL);
        if (!dbdev_tab)
                return -ENOMEM;

        memcpy(dbdev_tab, idtable, 32 * sizeof(dbdev_tab_t));
        for (ret = 32; ret < DBDEV_TAB_SIZE; ret++)
                dbdev_tab[ret].dev_id = ~0;

        dbdma_gptr->ddma_config = 0;
        dbdma_gptr->ddma_throttle = 0;
        dbdma_gptr->ddma_inten = 0xffff;
        wmb(); /* drain writebuffer */

        ret = request_irq(irq, dbdma_interrupt, 0, "dbdma", (void *)dbdma_gptr);
        if (ret)
                printk(KERN_ERR "Cannot grab DBDMA interrupt!\n");
        else {
                dbdma_initialized = 1;
                register_syscore_ops(&alchemy_dbdma_syscore_ops);
        }

        return ret;
}

static int __init alchemy_dbdma_init(void)
{
        switch (alchemy_get_cputype()) {
        case ALCHEMY_CPU_AU1550:
                return dbdma_setup(AU1550_DDMA_INT, au1550_dbdev_tab);
        case ALCHEMY_CPU_AU1200:
                return dbdma_setup(AU1200_DDMA_INT, au1200_dbdev_tab);
        case ALCHEMY_CPU_AU1300:
                return dbdma_setup(AU1300_DDMA_INT, au1300_dbdev_tab);
        }
        return 0;
}
subsys_initcall(alchemy_dbdma_init);