etraxfs_dma.c

/*
 * QEMU ETRAX DMA Controller.
 *
 * Copyright (c) 2008 Edgar E. Iglesias, Axis Communications AB.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include <stdio.h>
#include <sys/time.h>
#include "hw.h"
#include "exec-memory.h"
#include "qemu-common.h"
#include "sysemu.h"

#include "etraxfs_dma.h"

#define D(x)

#define RW_DATA           (0x0 / 4)
#define RW_SAVED_DATA     (0x58 / 4)
#define RW_SAVED_DATA_BUF (0x5c / 4)
#define RW_GROUP          (0x60 / 4)
#define RW_GROUP_DOWN     (0x7c / 4)
#define RW_CMD            (0x80 / 4)
#define RW_CFG            (0x84 / 4)
#define RW_STAT           (0x88 / 4)
#define RW_INTR_MASK      (0x8c / 4)
#define RW_ACK_INTR       (0x90 / 4)
#define R_INTR            (0x94 / 4)
#define R_MASKED_INTR     (0x98 / 4)
#define RW_STREAM_CMD     (0x9c / 4)

#define DMA_REG_MAX       (0x100 / 4)

/* descriptors */

// ------------------------------------------------------------ dma_descr_group
typedef struct dma_descr_group {
  uint32_t                      next;
  unsigned                      eol        : 1;
  unsigned                      tol        : 1;
  unsigned                      bol        : 1;
  unsigned                                 : 1;
  unsigned                      intr       : 1;
  unsigned                                 : 2;
  unsigned                      en         : 1;
  unsigned                                 : 7;
  unsigned                      dis        : 1;
  unsigned                      md         : 16;
  struct dma_descr_group       *up;
  union {
    struct dma_descr_context   *context;
    struct dma_descr_group     *group;
  }                             down;
} dma_descr_group;

// ---------------------------------------------------------- dma_descr_context
typedef struct dma_descr_context {
  uint32_t                      next;
  unsigned                      eol        : 1;
  unsigned                                 : 3;
  unsigned                      intr       : 1;
  unsigned                                 : 1;
  unsigned                      store_mode : 1;
  unsigned                      en         : 1;
  unsigned                                 : 7;
  unsigned                      dis        : 1;
  unsigned                      md0        : 16;
  unsigned                      md1;
  unsigned                      md2;
  unsigned                      md3;
  unsigned                      md4;
  uint32_t                      saved_data;
  uint32_t                      saved_data_buf;
} dma_descr_context;

// ------------------------------------------------------------- dma_descr_data
typedef struct dma_descr_data {
  uint32_t                      next;
  uint32_t                      buf;
  unsigned                      eol        : 1;
  unsigned                                 : 2;
  unsigned                      out_eop    : 1;
  unsigned                      intr       : 1;
  unsigned                      wait       : 1;
  unsigned                                 : 2;
  unsigned                                 : 3;
  unsigned                      in_eop     : 1;
  unsigned                                 : 4;
  unsigned                      md         : 16;
  uint32_t                      after;
} dma_descr_data;

/* Constants */
enum {
  regk_dma_ack_pkt                         = 0x00000100,
  regk_dma_anytime                         = 0x00000001,
  regk_dma_array                           = 0x00000008,
  regk_dma_burst                           = 0x00000020,
  regk_dma_client                          = 0x00000002,
  regk_dma_copy_next                       = 0x00000010,
  regk_dma_copy_up                         = 0x00000020,
  regk_dma_data_at_eol                     = 0x00000001,
  regk_dma_dis_c                           = 0x00000010,
  regk_dma_dis_g                           = 0x00000020,
  regk_dma_idle                            = 0x00000001,
  regk_dma_intern                          = 0x00000004,
  regk_dma_load_c                          = 0x00000200,
  regk_dma_load_c_n                        = 0x00000280,
  regk_dma_load_c_next                     = 0x00000240,
  regk_dma_load_d                          = 0x00000140,
  regk_dma_load_g                          = 0x00000300,
  regk_dma_load_g_down                     = 0x000003c0,
  regk_dma_load_g_next                     = 0x00000340,
  regk_dma_load_g_up                       = 0x00000380,
  regk_dma_next_en                         = 0x00000010,
  regk_dma_next_pkt                        = 0x00000010,
  regk_dma_no                              = 0x00000000,
  regk_dma_only_at_wait                    = 0x00000000,
  regk_dma_restore                         = 0x00000020,
  regk_dma_rst                             = 0x00000001,
  regk_dma_running                         = 0x00000004,
  regk_dma_rw_cfg_default                  = 0x00000000,
  regk_dma_rw_cmd_default                  = 0x00000000,
  regk_dma_rw_intr_mask_default            = 0x00000000,
  regk_dma_rw_stat_default                 = 0x00000101,
  regk_dma_rw_stream_cmd_default           = 0x00000000,
  regk_dma_save_down                       = 0x00000020,
  regk_dma_save_up                         = 0x00000020,
  regk_dma_set_reg                         = 0x00000050,
  regk_dma_set_w_size1                     = 0x00000190,
  regk_dma_set_w_size2                     = 0x000001a0,
  regk_dma_set_w_size4                     = 0x000001c0,
  regk_dma_stopped                         = 0x00000002,
  regk_dma_store_c                         = 0x00000002,
  regk_dma_store_descr                     = 0x00000000,
  regk_dma_store_g                         = 0x00000004,
  regk_dma_store_md                        = 0x00000001,
  regk_dma_sw                              = 0x00000008,
  regk_dma_update_down                     = 0x00000020,
  regk_dma_yes                             = 0x00000001
};

enum dma_ch_state
{
	RST = 1,
	STOPPED = 2,
	RUNNING = 4
};

struct fs_dma_channel
{
	qemu_irq irq;
	struct etraxfs_dma_client *client;

	/* Internal status.  */
	int stream_cmd_src;
	enum dma_ch_state state;

	unsigned int input : 1;
	unsigned int eol : 1;

	struct dma_descr_group current_g;
	struct dma_descr_context current_c;
	struct dma_descr_data current_d;

	/* Control registers.  */
	uint32_t regs[DMA_REG_MAX];
};

struct fs_dma_ctrl
{
	MemoryRegion mmio;
	int nr_channels;
	struct fs_dma_channel *channels;

        QEMUBH *bh;
};

static void DMA_run(void *opaque);
static int channel_out_run(struct fs_dma_ctrl *ctrl, int c);

static inline uint32_t channel_reg(struct fs_dma_ctrl *ctrl, int c, int reg)
{
	return ctrl->channels[c].regs[reg];
}

static inline int channel_stopped(struct fs_dma_ctrl *ctrl, int c)
{
	return channel_reg(ctrl, c, RW_CFG) & 2;
}

static inline int channel_en(struct fs_dma_ctrl *ctrl, int c)
{
	return (channel_reg(ctrl, c, RW_CFG) & 1)
		&& ctrl->channels[c].client;
}

static inline int fs_channel(target_phys_addr_t addr)
{
	/* Every channel has a 0x2000 ctrl register map.  */
	return addr >> 13;
}

#ifdef USE_THIS_DEAD_CODE
static void channel_load_g(struct fs_dma_ctrl *ctrl, int c)
{
	target_phys_addr_t addr = channel_reg(ctrl, c, RW_GROUP);

	/* Load and decode. FIXME: handle endianness.  */
	cpu_physical_memory_read (addr, 
				  (void *) &ctrl->channels[c].current_g, 
				  sizeof ctrl->channels[c].current_g);
}

static void dump_c(int ch, struct dma_descr_context *c)
{
	printf("%s ch=%d\n", __func__, ch);
	printf("next=%x\n", c->next);
	printf("saved_data=%x\n", c->saved_data);
	printf("saved_data_buf=%x\n", c->saved_data_buf);
	printf("eol=%x\n", (uint32_t) c->eol);
}

static void dump_d(int ch, struct dma_descr_data *d)
{
	printf("%s ch=%d\n", __func__, ch);
	printf("next=%x\n", d->next);
	printf("buf=%x\n", d->buf);
	printf("after=%x\n", d->after);
	printf("intr=%x\n", (uint32_t) d->intr);
	printf("out_eop=%x\n", (uint32_t) d->out_eop);
	printf("in_eop=%x\n", (uint32_t) d->in_eop);
	printf("eol=%x\n", (uint32_t) d->eol);
}
#endif

static void channel_load_c(struct fs_dma_ctrl *ctrl, int c)
{
	target_phys_addr_t addr = channel_reg(ctrl, c, RW_GROUP_DOWN);

	/* Load and decode. FIXME: handle endianness.  */
	cpu_physical_memory_read (addr, 
				  (void *) &ctrl->channels[c].current_c, 
				  sizeof ctrl->channels[c].current_c);

	D(dump_c(c, &ctrl->channels[c].current_c));
	/* I guess this should update the current pos.  */
	ctrl->channels[c].regs[RW_SAVED_DATA] =
		(uint32_t)(unsigned long)ctrl->channels[c].current_c.saved_data;
	ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
		(uint32_t)(unsigned long)ctrl->channels[c].current_c.saved_data_buf;
}

static void channel_load_d(struct fs_dma_ctrl *ctrl, int c)
{
	target_phys_addr_t addr = channel_reg(ctrl, c, RW_SAVED_DATA);

	/* Load and decode. FIXME: handle endianness.  */
	D(printf("%s ch=%d addr=" TARGET_FMT_plx "\n", __func__, c, addr));
	cpu_physical_memory_read (addr,
				  (void *) &ctrl->channels[c].current_d, 
				  sizeof ctrl->channels[c].current_d);

	D(dump_d(c, &ctrl->channels[c].current_d));
	ctrl->channels[c].regs[RW_DATA] = addr;
}

static void channel_store_c(struct fs_dma_ctrl *ctrl, int c)
{
	target_phys_addr_t addr = channel_reg(ctrl, c, RW_GROUP_DOWN);

	/* Encode and store. FIXME: handle endianness.  */
	D(printf("%s ch=%d addr=" TARGET_FMT_plx "\n", __func__, c, addr));
	D(dump_d(c, &ctrl->channels[c].current_d));
	cpu_physical_memory_write (addr,
				  (void *) &ctrl->channels[c].current_c,
				  sizeof ctrl->channels[c].current_c);
}

static void channel_store_d(struct fs_dma_ctrl *ctrl, int c)
{
	target_phys_addr_t addr = channel_reg(ctrl, c, RW_SAVED_DATA);

	/* Encode and store. FIXME: handle endianness.  */
	D(printf("%s ch=%d addr=" TARGET_FMT_plx "\n", __func__, c, addr));
	cpu_physical_memory_write (addr,
				  (void *) &ctrl->channels[c].current_d, 
				  sizeof ctrl->channels[c].current_d);
}

static inline void channel_stop(struct fs_dma_ctrl *ctrl, int c)
{
	/* FIXME:  */
}

static inline void channel_start(struct fs_dma_ctrl *ctrl, int c)
{
	if (ctrl->channels[c].client)
	{
		ctrl->channels[c].eol = 0;
		ctrl->channels[c].state = RUNNING;
		if (!ctrl->channels[c].input)
			channel_out_run(ctrl, c);
	} else
		printf("WARNING: starting DMA ch %d with no client\n", c);

        qemu_bh_schedule_idle(ctrl->bh);
}

static void channel_continue(struct fs_dma_ctrl *ctrl, int c)
{
	if (!channel_en(ctrl, c) 
	    || channel_stopped(ctrl, c)
	    || ctrl->channels[c].state != RUNNING
	    /* Only reload the current data descriptor if it has eol set.  */
	    || !ctrl->channels[c].current_d.eol) {
		D(printf("continue failed ch=%d state=%d stopped=%d en=%d eol=%d\n", 
			 c, ctrl->channels[c].state,
			 channel_stopped(ctrl, c),
			 channel_en(ctrl,c),
			 ctrl->channels[c].eol));
		D(dump_d(c, &ctrl->channels[c].current_d));
		return;
	}

	/* Reload the current descriptor.  */
	channel_load_d(ctrl, c);

	/* If the current descriptor cleared the eol flag and we had already
	   reached eol state, do the continue.  */
	if (!ctrl->channels[c].current_d.eol && ctrl->channels[c].eol) {
		D(printf("continue %d ok %x\n", c,
			 ctrl->channels[c].current_d.next));
		ctrl->channels[c].regs[RW_SAVED_DATA] =
			(uint32_t)(unsigned long)ctrl->channels[c].current_d.next;
		channel_load_d(ctrl, c);
		ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
			(uint32_t)(unsigned long)ctrl->channels[c].current_d.buf;

		channel_start(ctrl, c);
	}
	ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
		(uint32_t)(unsigned long)ctrl->channels[c].current_d.buf;
}

static void channel_stream_cmd(struct fs_dma_ctrl *ctrl, int c, uint32_t v)
{
	unsigned int cmd = v & ((1 << 10) - 1);

	D(printf("%s ch=%d cmd=%x\n",
		 __func__, c, cmd));
	if (cmd & regk_dma_load_d) {
		channel_load_d(ctrl, c);
		if (cmd & regk_dma_burst)
			channel_start(ctrl, c);
	}

	if (cmd & regk_dma_load_c) {
		channel_load_c(ctrl, c);
	}
}

static void channel_update_irq(struct fs_dma_ctrl *ctrl, int c)
{
	D(printf("%s %d\n", __func__, c));
        ctrl->channels[c].regs[R_INTR] &=
		~(ctrl->channels[c].regs[RW_ACK_INTR]);

        ctrl->channels[c].regs[R_MASKED_INTR] =
		ctrl->channels[c].regs[R_INTR]
		& ctrl->channels[c].regs[RW_INTR_MASK];

	D(printf("%s: chan=%d masked_intr=%x\n", __func__, 
		 c,
		 ctrl->channels[c].regs[R_MASKED_INTR]));

        qemu_set_irq(ctrl->channels[c].irq,
		     !!ctrl->channels[c].regs[R_MASKED_INTR]);
}

static int channel_out_run(struct fs_dma_ctrl *ctrl, int c)
{
	uint32_t len;
	uint32_t saved_data_buf;
	unsigned char buf[2 * 1024];

	struct dma_context_metadata meta;
	bool send_context = true;

	if (ctrl->channels[c].eol)
		return 0;

	do {
		bool out_eop;
		D(printf("ch=%d buf=%x after=%x\n",
			 c,
			 (uint32_t)ctrl->channels[c].current_d.buf,
			 (uint32_t)ctrl->channels[c].current_d.after));

		if (send_context) {
			if (ctrl->channels[c].client->client.metadata_push) {
				meta.metadata = ctrl->channels[c].current_d.md;
				ctrl->channels[c].client->client.metadata_push(
					ctrl->channels[c].client->client.opaque,
					&meta);
			}
			send_context = false;
		}

		channel_load_d(ctrl, c);
		saved_data_buf = channel_reg(ctrl, c, RW_SAVED_DATA_BUF);
		len = (uint32_t)(unsigned long)
			ctrl->channels[c].current_d.after;
		len -= saved_data_buf;

		if (len > sizeof buf)
			len = sizeof buf;
		cpu_physical_memory_read (saved_data_buf, buf, len);

		out_eop = ((saved_data_buf + len) ==
		           ctrl->channels[c].current_d.after) &&
			ctrl->channels[c].current_d.out_eop;

		D(printf("channel %d pushes %x %u bytes eop=%u\n", c,
		         saved_data_buf, len, out_eop));

		if (ctrl->channels[c].client->client.push)
			ctrl->channels[c].client->client.push(
				ctrl->channels[c].client->client.opaque,
				buf, len, out_eop);
		else
			printf("WARNING: DMA ch%d dataloss,"
			       " no attached client.\n", c);

		saved_data_buf += len;

		if (saved_data_buf == (uint32_t)(unsigned long)
				ctrl->channels[c].current_d.after) {
			/* Done. Step to next.  */
			if (ctrl->channels[c].current_d.out_eop) {
				send_context = true;
			}
			if (ctrl->channels[c].current_d.intr) {
				/* data intr.  */
				D(printf("signal intr %d eol=%d\n",
					len, ctrl->channels[c].current_d.eol));
				ctrl->channels[c].regs[R_INTR] |= (1 << 2);
				channel_update_irq(ctrl, c);
			}
			channel_store_d(ctrl, c);
			if (ctrl->channels[c].current_d.eol) {
				D(printf("channel %d EOL\n", c));
				ctrl->channels[c].eol = 1;

				/* Mark the context as disabled.  */
				ctrl->channels[c].current_c.dis = 1;
				channel_store_c(ctrl, c);

				channel_stop(ctrl, c);
			} else {
				ctrl->channels[c].regs[RW_SAVED_DATA] =
					(uint32_t)(unsigned long)ctrl->
						channels[c].current_d.next;
				/* Load new descriptor.  */
				channel_load_d(ctrl, c);
				saved_data_buf = (uint32_t)(unsigned long)
					ctrl->channels[c].current_d.buf;
			}

			ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
							saved_data_buf;
			D(dump_d(c, &ctrl->channels[c].current_d));
		}
		ctrl->channels[c].regs[RW_SAVED_DATA_BUF] = saved_data_buf;
	} while (!ctrl->channels[c].eol);
	return 1;
}

static int channel_in_process(struct fs_dma_ctrl *ctrl, int c, 
			      unsigned char *buf, int buflen, int eop)
{
	uint32_t len;
	uint32_t saved_data_buf;

	if (ctrl->channels[c].eol == 1)
		return 0;

	channel_load_d(ctrl, c);
	saved_data_buf = channel_reg(ctrl, c, RW_SAVED_DATA_BUF);
	len = (uint32_t)(unsigned long)ctrl->channels[c].current_d.after;
	len -= saved_data_buf;
	
	if (len > buflen)
		len = buflen;

	cpu_physical_memory_write (saved_data_buf, buf, len);
	saved_data_buf += len;

	if (saved_data_buf ==
	    (uint32_t)(unsigned long)ctrl->channels[c].current_d.after
	    || eop) {
		uint32_t r_intr = ctrl->channels[c].regs[R_INTR];

		D(printf("in dscr end len=%d\n", 
			 ctrl->channels[c].current_d.after
			 - ctrl->channels[c].current_d.buf));
		ctrl->channels[c].current_d.after = saved_data_buf;

		/* Done. Step to next.  */
		if (ctrl->channels[c].current_d.intr) {
			/* TODO: signal eop to the client.  */
			/* data intr.  */
			ctrl->channels[c].regs[R_INTR] |= 3;
		}
		if (eop) {
			ctrl->channels[c].current_d.in_eop = 1;
			ctrl->channels[c].regs[R_INTR] |= 8;
		}
		if (r_intr != ctrl->channels[c].regs[R_INTR])
			channel_update_irq(ctrl, c);

		channel_store_d(ctrl, c);
		D(dump_d(c, &ctrl->channels[c].current_d));

		if (ctrl->channels[c].current_d.eol) {
			D(printf("channel %d EOL\n", c));
			ctrl->channels[c].eol = 1;

			/* Mark the context as disabled.  */
			ctrl->channels[c].current_c.dis = 1;
			channel_store_c(ctrl, c);

			channel_stop(ctrl, c);
		} else {
			ctrl->channels[c].regs[RW_SAVED_DATA] =
				(uint32_t)(unsigned long)ctrl->
					channels[c].current_d.next;
			/* Load new descriptor.  */
			channel_load_d(ctrl, c);
			saved_data_buf = (uint32_t)(unsigned long)
				ctrl->channels[c].current_d.buf;
		}
	}

	ctrl->channels[c].regs[RW_SAVED_DATA_BUF] = saved_data_buf;
	return len;
}

static inline int channel_in_run(struct fs_dma_ctrl *ctrl, int c)
{
	if (ctrl->channels[c].client->client.pull) {
		ctrl->channels[c].client->client.pull(
			ctrl->channels[c].client->client.opaque);
		return 1;
	} else
		return 0;
}

static uint32_t dma_rinvalid (void *opaque, target_phys_addr_t addr)
{
        hw_error("Unsupported short raccess. reg=" TARGET_FMT_plx "\n", addr);
        return 0;
}

static uint64_t
dma_read(void *opaque, target_phys_addr_t addr, unsigned int size)
{
        struct fs_dma_ctrl *ctrl = opaque;
	int c;
	uint32_t r = 0;

	if (size != 4) {
		dma_rinvalid(opaque, addr);
	}

	/* Make addr relative to this channel and bounded to nr regs.  */
	c = fs_channel(addr);
	addr &= 0xff;
	addr >>= 2;
	switch (addr)
	{
		case RW_STAT:
			r = ctrl->channels[c].state & 7;
			r |= ctrl->channels[c].eol << 5;
			r |= ctrl->channels[c].stream_cmd_src << 8;
			break;

		default:
			r = ctrl->channels[c].regs[addr];
			D(printf ("%s c=%d addr=" TARGET_FMT_plx "\n",
				  __func__, c, addr));
			break;
	}
	return r;
}

static void
dma_winvalid (void *opaque, target_phys_addr_t addr, uint32_t value)
{
        hw_error("Unsupported short waccess. reg=" TARGET_FMT_plx "\n", addr);
}

static void
dma_update_state(struct fs_dma_ctrl *ctrl, int c)
{
	if (ctrl->channels[c].regs[RW_CFG] & 2)
		ctrl->channels[c].state = STOPPED;
	if (!(ctrl->channels[c].regs[RW_CFG] & 1))
		ctrl->channels[c].state = RST;
}

static void
dma_write(void *opaque, target_phys_addr_t addr,
	  uint64_t val64, unsigned int size)
{
        struct fs_dma_ctrl *ctrl = opaque;
	uint32_t value = val64;
	int c;

	if (size != 4) {
		dma_winvalid(opaque, addr, value);
	}

        /* Make addr relative to this channel and bounded to nr regs.  */
	c = fs_channel(addr);
        addr &= 0xff;
        addr >>= 2;
        switch (addr)
	{
		case RW_DATA:
			ctrl->channels[c].regs[addr] = value;
			break;

		case RW_CFG:
			ctrl->channels[c].regs[addr] = value;
			dma_update_state(ctrl, c);
			break;
		case RW_CMD:
			/* continue.  */
			if (value & ~1)
				printf("Invalid store to ch=%d RW_CMD %x\n",
				       c, value);
			ctrl->channels[c].regs[addr] = value;
			channel_continue(ctrl, c);
			break;

		case RW_SAVED_DATA:
		case RW_SAVED_DATA_BUF:
		case RW_GROUP:
		case RW_GROUP_DOWN:
			ctrl->channels[c].regs[addr] = value;
			break;

		case RW_ACK_INTR:
		case RW_INTR_MASK:
			ctrl->channels[c].regs[addr] = value;
			channel_update_irq(ctrl, c);
			if (addr == RW_ACK_INTR)
				ctrl->channels[c].regs[RW_ACK_INTR] = 0;
			break;

		case RW_STREAM_CMD:
			if (value & ~1023)
				printf("Invalid store to ch=%d "
				       "RW_STREAMCMD %x\n",
				       c, value);
			ctrl->channels[c].regs[addr] = value;
			D(printf("stream_cmd ch=%d\n", c));
			channel_stream_cmd(ctrl, c, value);
			break;

	        default:
			D(printf ("%s c=%d " TARGET_FMT_plx "\n",
				__func__, c, addr));
			break;
        }
}

static const MemoryRegionOps dma_ops = {
	.read = dma_read,
	.write = dma_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.valid = {
		.min_access_size = 1,
		.max_access_size = 4
	}
};

static int etraxfs_dmac_run(void *opaque)
{
	struct fs_dma_ctrl *ctrl = opaque;
	int i;
	int p = 0;

	for (i = 0; 
	     i < ctrl->nr_channels;
	     i++)
	{
		if (ctrl->channels[i].state == RUNNING)
		{
			if (ctrl->channels[i].input) {
				p += channel_in_run(ctrl, i);
			} else {
				p += channel_out_run(ctrl, i);
			}
		}
	}
	return p;
}

int etraxfs_dmac_input(struct etraxfs_dma_client *client, 
		       void *buf, int len, int eop)
{
	return channel_in_process(client->ctrl, client->channel, 
				  buf, len, eop);
}

/* Connect an IRQ line with a channel.  */
void etraxfs_dmac_connect(void *opaque, int c, qemu_irq *line, int input)
{
	struct fs_dma_ctrl *ctrl = opaque;
	ctrl->channels[c].irq = *line;
	ctrl->channels[c].input = input;
}

void etraxfs_dmac_connect_client(void *opaque, int c, 
				 struct etraxfs_dma_client *cl)
{
	struct fs_dma_ctrl *ctrl = opaque;
	cl->ctrl = ctrl;
	cl->channel = c;
	ctrl->channels[c].client = cl;
}


static void DMA_run(void *opaque)
{
    struct fs_dma_ctrl *etraxfs_dmac = opaque;
    int p = 1;

    if (runstate_is_running())
        p = etraxfs_dmac_run(etraxfs_dmac);

    if (p)
        qemu_bh_schedule_idle(etraxfs_dmac->bh);
}

void *etraxfs_dmac_init(target_phys_addr_t base, int nr_channels)
{
	struct fs_dma_ctrl *ctrl = NULL;

	ctrl = g_malloc0(sizeof *ctrl);

        ctrl->bh = qemu_bh_new(DMA_run, ctrl);

	ctrl->nr_channels = nr_channels;
	ctrl->channels = g_malloc0(sizeof ctrl->channels[0] * nr_channels);

	memory_region_init_io(&ctrl->mmio, &dma_ops, ctrl, "etraxfs-dma",
			      nr_channels * 0x2000);
	memory_region_add_subregion(get_system_memory(), base, &ctrl->mmio);

	return ctrl;
}