qemu/hw/etraxfs_dma.c
Alexander Graf 2507c12ab0 Add endianness as io mem parameter
As stated before, devices can be little, big or native endian. The
target endianness is not of their concern, so we need to push things
down a level.

This patch adds a parameter to cpu_register_io_memory that allows a
device to choose its endianness. For now, all devices simply choose
native endian, because that's the same behavior as before.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-12-11 15:24:25 +00:00

757 lines
22 KiB
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 "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;
/* Controll registers. */
uint32_t regs[DMA_REG_MAX];
};
struct fs_dma_ctrl
{
int map;
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];
if (ctrl->channels[c].eol)
return 0;
do {
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));
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);
D(printf("channel %d pushes %x %u bytes\n", c,
saved_data_buf, len));
if (ctrl->channels[c].client->client.push)
ctrl->channels[c].client->client.push(
ctrl->channels[c].client->client.opaque,
buf, len);
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) {
/* TODO: signal eop to the client. */
D(printf("signal eop\n"));
}
if (ctrl->channels[c].current_d.intr) {
/* TODO: signal eop to the client. */
/* 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 uint32_t
dma_readl (void *opaque, target_phys_addr_t addr)
{
struct fs_dma_ctrl *ctrl = opaque;
int c;
uint32_t r = 0;
/* 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] & 1) != 3) {
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_writel (void *opaque, target_phys_addr_t addr, uint32_t value)
{
struct fs_dma_ctrl *ctrl = opaque;
int c;
/* 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 CPUReadMemoryFunc * const dma_read[] = {
&dma_rinvalid,
&dma_rinvalid,
&dma_readl,
};
static CPUWriteMemoryFunc * const dma_write[] = {
&dma_winvalid,
&dma_winvalid,
&dma_writel,
};
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 (vm_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 = qemu_mallocz(sizeof *ctrl);
ctrl->bh = qemu_bh_new(DMA_run, ctrl);
ctrl->nr_channels = nr_channels;
ctrl->channels = qemu_mallocz(sizeof ctrl->channels[0] * nr_channels);
ctrl->map = cpu_register_io_memory(dma_read, dma_write, ctrl, DEVICE_NATIVE_ENDIAN);
cpu_register_physical_memory(base, nr_channels * 0x2000, ctrl->map);
return ctrl;
}