/* * PowerMac descriptor-based DMA emulation * * Copyright (c) 2005-2007 Fabrice Bellard * Copyright (c) 2007 Jocelyn Mayer * Copyright (c) 2009 Laurent Vivier * * some parts from linux-2.6.28, arch/powerpc/include/asm/dbdma.h * * Definitions for using the Apple Descriptor-Based DMA controller * in Power Macintosh computers. * * Copyright (C) 1996 Paul Mackerras. * * some parts from mol 0.9.71 * * Descriptor based DMA emulation * * Copyright (C) 1998-2004 Samuel Rydh (samuel@ibrium.se) * * 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 "hw.h" #include "isa.h" #include "mac_dbdma.h" /* debug DBDMA */ //#define DEBUG_DBDMA #ifdef DEBUG_DBDMA #define DBDMA_DPRINTF(fmt, ...) \ do { printf("DBDMA: " fmt , ## __VA_ARGS__); } while (0) #else #define DBDMA_DPRINTF(fmt, ...) #endif /* */ /* * DBDMA control/status registers. All little-endian. */ #define DBDMA_CONTROL 0x00 #define DBDMA_STATUS 0x01 #define DBDMA_CMDPTR_HI 0x02 #define DBDMA_CMDPTR_LO 0x03 #define DBDMA_INTR_SEL 0x04 #define DBDMA_BRANCH_SEL 0x05 #define DBDMA_WAIT_SEL 0x06 #define DBDMA_XFER_MODE 0x07 #define DBDMA_DATA2PTR_HI 0x08 #define DBDMA_DATA2PTR_LO 0x09 #define DBDMA_RES1 0x0A #define DBDMA_ADDRESS_HI 0x0B #define DBDMA_BRANCH_ADDR_HI 0x0C #define DBDMA_RES2 0x0D #define DBDMA_RES3 0x0E #define DBDMA_RES4 0x0F #define DBDMA_REGS 16 #define DBDMA_SIZE (DBDMA_REGS * sizeof(uint32_t)) #define DBDMA_CHANNEL_SHIFT 7 #define DBDMA_CHANNEL_SIZE (1 << DBDMA_CHANNEL_SHIFT) #define DBDMA_CHANNELS (0x1000 >> DBDMA_CHANNEL_SHIFT) /* Bits in control and status registers */ #define RUN 0x8000 #define PAUSE 0x4000 #define FLUSH 0x2000 #define WAKE 0x1000 #define DEAD 0x0800 #define ACTIVE 0x0400 #define BT 0x0100 #define DEVSTAT 0x00ff /* * DBDMA command structure. These fields are all little-endian! */ typedef struct dbdma_cmd { uint16_t req_count; /* requested byte transfer count */ uint16_t command; /* command word (has bit-fields) */ uint32_t phy_addr; /* physical data address */ uint32_t cmd_dep; /* command-dependent field */ uint16_t res_count; /* residual count after completion */ uint16_t xfer_status; /* transfer status */ } dbdma_cmd; /* DBDMA command values in command field */ #define COMMAND_MASK 0xf000 #define OUTPUT_MORE 0x0000 /* transfer memory data to stream */ #define OUTPUT_LAST 0x1000 /* ditto followed by end marker */ #define INPUT_MORE 0x2000 /* transfer stream data to memory */ #define INPUT_LAST 0x3000 /* ditto, expect end marker */ #define STORE_WORD 0x4000 /* write word (4 bytes) to device reg */ #define LOAD_WORD 0x5000 /* read word (4 bytes) from device reg */ #define DBDMA_NOP 0x6000 /* do nothing */ #define DBDMA_STOP 0x7000 /* suspend processing */ /* Key values in command field */ #define KEY_MASK 0x0700 #define KEY_STREAM0 0x0000 /* usual data stream */ #define KEY_STREAM1 0x0100 /* control/status stream */ #define KEY_STREAM2 0x0200 /* device-dependent stream */ #define KEY_STREAM3 0x0300 /* device-dependent stream */ #define KEY_STREAM4 0x0400 /* reserved */ #define KEY_REGS 0x0500 /* device register space */ #define KEY_SYSTEM 0x0600 /* system memory-mapped space */ #define KEY_DEVICE 0x0700 /* device memory-mapped space */ /* Interrupt control values in command field */ #define INTR_MASK 0x0030 #define INTR_NEVER 0x0000 /* don't interrupt */ #define INTR_IFSET 0x0010 /* intr if condition bit is 1 */ #define INTR_IFCLR 0x0020 /* intr if condition bit is 0 */ #define INTR_ALWAYS 0x0030 /* always interrupt */ /* Branch control values in command field */ #define BR_MASK 0x000c #define BR_NEVER 0x0000 /* don't branch */ #define BR_IFSET 0x0004 /* branch if condition bit is 1 */ #define BR_IFCLR 0x0008 /* branch if condition bit is 0 */ #define BR_ALWAYS 0x000c /* always branch */ /* Wait control values in command field */ #define WAIT_MASK 0x0003 #define WAIT_NEVER 0x0000 /* don't wait */ #define WAIT_IFSET 0x0001 /* wait if condition bit is 1 */ #define WAIT_IFCLR 0x0002 /* wait if condition bit is 0 */ #define WAIT_ALWAYS 0x0003 /* always wait */ typedef struct DBDMA_channel { int channel; uint32_t regs[DBDMA_REGS]; qemu_irq irq; DBDMA_io io; DBDMA_rw rw; DBDMA_flush flush; dbdma_cmd current; int processing; } DBDMA_channel; typedef struct { MemoryRegion mem; DBDMA_channel channels[DBDMA_CHANNELS]; } DBDMAState; #ifdef DEBUG_DBDMA static void dump_dbdma_cmd(dbdma_cmd *cmd) { printf("dbdma_cmd %p\n", cmd); printf(" req_count 0x%04x\n", le16_to_cpu(cmd->req_count)); printf(" command 0x%04x\n", le16_to_cpu(cmd->command)); printf(" phy_addr 0x%08x\n", le32_to_cpu(cmd->phy_addr)); printf(" cmd_dep 0x%08x\n", le32_to_cpu(cmd->cmd_dep)); printf(" res_count 0x%04x\n", le16_to_cpu(cmd->res_count)); printf(" xfer_status 0x%04x\n", le16_to_cpu(cmd->xfer_status)); } #else static void dump_dbdma_cmd(dbdma_cmd *cmd) { } #endif static void dbdma_cmdptr_load(DBDMA_channel *ch) { DBDMA_DPRINTF("dbdma_cmdptr_load 0x%08x\n", ch->regs[DBDMA_CMDPTR_LO]); cpu_physical_memory_read(ch->regs[DBDMA_CMDPTR_LO], (uint8_t*)&ch->current, sizeof(dbdma_cmd)); } static void dbdma_cmdptr_save(DBDMA_channel *ch) { DBDMA_DPRINTF("dbdma_cmdptr_save 0x%08x\n", ch->regs[DBDMA_CMDPTR_LO]); DBDMA_DPRINTF("xfer_status 0x%08x res_count 0x%04x\n", le16_to_cpu(ch->current.xfer_status), le16_to_cpu(ch->current.res_count)); cpu_physical_memory_write(ch->regs[DBDMA_CMDPTR_LO], (uint8_t*)&ch->current, sizeof(dbdma_cmd)); } static void kill_channel(DBDMA_channel *ch) { DBDMA_DPRINTF("kill_channel\n"); ch->regs[DBDMA_STATUS] |= DEAD; ch->regs[DBDMA_STATUS] &= ~ACTIVE; qemu_irq_raise(ch->irq); } static void conditional_interrupt(DBDMA_channel *ch) { dbdma_cmd *current = &ch->current; uint16_t intr; uint16_t sel_mask, sel_value; uint32_t status; int cond; DBDMA_DPRINTF("conditional_interrupt\n"); intr = le16_to_cpu(current->command) & INTR_MASK; switch(intr) { case INTR_NEVER: /* don't interrupt */ return; case INTR_ALWAYS: /* always interrupt */ qemu_irq_raise(ch->irq); return; } status = ch->regs[DBDMA_STATUS] & DEVSTAT; sel_mask = (ch->regs[DBDMA_INTR_SEL] >> 16) & 0x0f; sel_value = ch->regs[DBDMA_INTR_SEL] & 0x0f; cond = (status & sel_mask) == (sel_value & sel_mask); switch(intr) { case INTR_IFSET: /* intr if condition bit is 1 */ if (cond) qemu_irq_raise(ch->irq); return; case INTR_IFCLR: /* intr if condition bit is 0 */ if (!cond) qemu_irq_raise(ch->irq); return; } } static int conditional_wait(DBDMA_channel *ch) { dbdma_cmd *current = &ch->current; uint16_t wait; uint16_t sel_mask, sel_value; uint32_t status; int cond; DBDMA_DPRINTF("conditional_wait\n"); wait = le16_to_cpu(current->command) & WAIT_MASK; switch(wait) { case WAIT_NEVER: /* don't wait */ return 0; case WAIT_ALWAYS: /* always wait */ return 1; } status = ch->regs[DBDMA_STATUS] & DEVSTAT; sel_mask = (ch->regs[DBDMA_WAIT_SEL] >> 16) & 0x0f; sel_value = ch->regs[DBDMA_WAIT_SEL] & 0x0f; cond = (status & sel_mask) == (sel_value & sel_mask); switch(wait) { case WAIT_IFSET: /* wait if condition bit is 1 */ if (cond) return 1; return 0; case WAIT_IFCLR: /* wait if condition bit is 0 */ if (!cond) return 1; return 0; } return 0; } static void next(DBDMA_channel *ch) { uint32_t cp; ch->regs[DBDMA_STATUS] &= ~BT; cp = ch->regs[DBDMA_CMDPTR_LO]; ch->regs[DBDMA_CMDPTR_LO] = cp + sizeof(dbdma_cmd); dbdma_cmdptr_load(ch); } static void branch(DBDMA_channel *ch) { dbdma_cmd *current = &ch->current; ch->regs[DBDMA_CMDPTR_LO] = current->cmd_dep; ch->regs[DBDMA_STATUS] |= BT; dbdma_cmdptr_load(ch); } static void conditional_branch(DBDMA_channel *ch) { dbdma_cmd *current = &ch->current; uint16_t br; uint16_t sel_mask, sel_value; uint32_t status; int cond; DBDMA_DPRINTF("conditional_branch\n"); /* check if we must branch */ br = le16_to_cpu(current->command) & BR_MASK; switch(br) { case BR_NEVER: /* don't branch */ next(ch); return; case BR_ALWAYS: /* always branch */ branch(ch); return; } status = ch->regs[DBDMA_STATUS] & DEVSTAT; sel_mask = (ch->regs[DBDMA_BRANCH_SEL] >> 16) & 0x0f; sel_value = ch->regs[DBDMA_BRANCH_SEL] & 0x0f; cond = (status & sel_mask) == (sel_value & sel_mask); switch(br) { case BR_IFSET: /* branch if condition bit is 1 */ if (cond) branch(ch); else next(ch); return; case BR_IFCLR: /* branch if condition bit is 0 */ if (!cond) branch(ch); else next(ch); return; } } static QEMUBH *dbdma_bh; static void channel_run(DBDMA_channel *ch); static void dbdma_end(DBDMA_io *io) { DBDMA_channel *ch = io->channel; dbdma_cmd *current = &ch->current; if (conditional_wait(ch)) goto wait; current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]); current->res_count = cpu_to_le16(io->len); dbdma_cmdptr_save(ch); if (io->is_last) ch->regs[DBDMA_STATUS] &= ~FLUSH; conditional_interrupt(ch); conditional_branch(ch); wait: ch->processing = 0; if ((ch->regs[DBDMA_STATUS] & RUN) && (ch->regs[DBDMA_STATUS] & ACTIVE)) channel_run(ch); } static void start_output(DBDMA_channel *ch, int key, uint32_t addr, uint16_t req_count, int is_last) { DBDMA_DPRINTF("start_output\n"); /* KEY_REGS, KEY_DEVICE and KEY_STREAM * are not implemented in the mac-io chip */ DBDMA_DPRINTF("addr 0x%x key 0x%x\n", addr, key); if (!addr || key > KEY_STREAM3) { kill_channel(ch); return; } ch->io.addr = addr; ch->io.len = req_count; ch->io.is_last = is_last; ch->io.dma_end = dbdma_end; ch->io.is_dma_out = 1; ch->processing = 1; if (ch->rw) { ch->rw(&ch->io); } } static void start_input(DBDMA_channel *ch, int key, uint32_t addr, uint16_t req_count, int is_last) { DBDMA_DPRINTF("start_input\n"); /* KEY_REGS, KEY_DEVICE and KEY_STREAM * are not implemented in the mac-io chip */ if (!addr || key > KEY_STREAM3) { kill_channel(ch); return; } ch->io.addr = addr; ch->io.len = req_count; ch->io.is_last = is_last; ch->io.dma_end = dbdma_end; ch->io.is_dma_out = 0; ch->processing = 1; if (ch->rw) { ch->rw(&ch->io); } } static void load_word(DBDMA_channel *ch, int key, uint32_t addr, uint16_t len) { dbdma_cmd *current = &ch->current; uint32_t val; DBDMA_DPRINTF("load_word\n"); /* only implements KEY_SYSTEM */ if (key != KEY_SYSTEM) { printf("DBDMA: LOAD_WORD, unimplemented key %x\n", key); kill_channel(ch); return; } cpu_physical_memory_read(addr, (uint8_t*)&val, len); if (len == 2) val = (val << 16) | (current->cmd_dep & 0x0000ffff); else if (len == 1) val = (val << 24) | (current->cmd_dep & 0x00ffffff); current->cmd_dep = val; if (conditional_wait(ch)) goto wait; current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]); dbdma_cmdptr_save(ch); ch->regs[DBDMA_STATUS] &= ~FLUSH; conditional_interrupt(ch); next(ch); wait: qemu_bh_schedule(dbdma_bh); } static void store_word(DBDMA_channel *ch, int key, uint32_t addr, uint16_t len) { dbdma_cmd *current = &ch->current; uint32_t val; DBDMA_DPRINTF("store_word\n"); /* only implements KEY_SYSTEM */ if (key != KEY_SYSTEM) { printf("DBDMA: STORE_WORD, unimplemented key %x\n", key); kill_channel(ch); return; } val = current->cmd_dep; if (len == 2) val >>= 16; else if (len == 1) val >>= 24; cpu_physical_memory_write(addr, (uint8_t*)&val, len); if (conditional_wait(ch)) goto wait; current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]); dbdma_cmdptr_save(ch); ch->regs[DBDMA_STATUS] &= ~FLUSH; conditional_interrupt(ch); next(ch); wait: qemu_bh_schedule(dbdma_bh); } static void nop(DBDMA_channel *ch) { dbdma_cmd *current = &ch->current; if (conditional_wait(ch)) goto wait; current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]); dbdma_cmdptr_save(ch); conditional_interrupt(ch); conditional_branch(ch); wait: qemu_bh_schedule(dbdma_bh); } static void stop(DBDMA_channel *ch) { ch->regs[DBDMA_STATUS] &= ~(ACTIVE|DEAD|FLUSH); /* the stop command does not increment command pointer */ } static void channel_run(DBDMA_channel *ch) { dbdma_cmd *current = &ch->current; uint16_t cmd, key; uint16_t req_count; uint32_t phy_addr; DBDMA_DPRINTF("channel_run\n"); dump_dbdma_cmd(current); /* clear WAKE flag at command fetch */ ch->regs[DBDMA_STATUS] &= ~WAKE; cmd = le16_to_cpu(current->command) & COMMAND_MASK; switch (cmd) { case DBDMA_NOP: nop(ch); return; case DBDMA_STOP: stop(ch); return; } key = le16_to_cpu(current->command) & 0x0700; req_count = le16_to_cpu(current->req_count); phy_addr = le32_to_cpu(current->phy_addr); if (key == KEY_STREAM4) { printf("command %x, invalid key 4\n", cmd); kill_channel(ch); return; } switch (cmd) { case OUTPUT_MORE: start_output(ch, key, phy_addr, req_count, 0); return; case OUTPUT_LAST: start_output(ch, key, phy_addr, req_count, 1); return; case INPUT_MORE: start_input(ch, key, phy_addr, req_count, 0); return; case INPUT_LAST: start_input(ch, key, phy_addr, req_count, 1); return; } if (key < KEY_REGS) { printf("command %x, invalid key %x\n", cmd, key); key = KEY_SYSTEM; } /* for LOAD_WORD and STORE_WORD, req_count is on 3 bits * and BRANCH is invalid */ req_count = req_count & 0x0007; if (req_count & 0x4) { req_count = 4; phy_addr &= ~3; } else if (req_count & 0x2) { req_count = 2; phy_addr &= ~1; } else req_count = 1; switch (cmd) { case LOAD_WORD: load_word(ch, key, phy_addr, req_count); return; case STORE_WORD: store_word(ch, key, phy_addr, req_count); return; } } static void DBDMA_run(DBDMAState *s) { int channel; for (channel = 0; channel < DBDMA_CHANNELS; channel++) { DBDMA_channel *ch = &s->channels[channel]; uint32_t status = ch->regs[DBDMA_STATUS]; if (!ch->processing && (status & RUN) && (status & ACTIVE)) { channel_run(ch); } } } static void DBDMA_run_bh(void *opaque) { DBDMAState *s = opaque; DBDMA_DPRINTF("DBDMA_run_bh\n"); DBDMA_run(s); } void DBDMA_register_channel(void *dbdma, int nchan, qemu_irq irq, DBDMA_rw rw, DBDMA_flush flush, void *opaque) { DBDMAState *s = dbdma; DBDMA_channel *ch = &s->channels[nchan]; DBDMA_DPRINTF("DBDMA_register_channel 0x%x\n", nchan); ch->irq = irq; ch->channel = nchan; ch->rw = rw; ch->flush = flush; ch->io.opaque = opaque; ch->io.channel = ch; } static void dbdma_control_write(DBDMA_channel *ch) { uint16_t mask, value; uint32_t status; mask = (ch->regs[DBDMA_CONTROL] >> 16) & 0xffff; value = ch->regs[DBDMA_CONTROL] & 0xffff; value &= (RUN | PAUSE | FLUSH | WAKE | DEVSTAT); status = ch->regs[DBDMA_STATUS]; status = (value & mask) | (status & ~mask); if (status & WAKE) status |= ACTIVE; if (status & RUN) { status |= ACTIVE; status &= ~DEAD; } if (status & PAUSE) status &= ~ACTIVE; if ((ch->regs[DBDMA_STATUS] & RUN) && !(status & RUN)) { /* RUN is cleared */ status &= ~(ACTIVE|DEAD); } DBDMA_DPRINTF(" status 0x%08x\n", status); ch->regs[DBDMA_STATUS] = status; if (status & ACTIVE) qemu_bh_schedule(dbdma_bh); if ((status & FLUSH) && ch->flush) ch->flush(&ch->io); } static void dbdma_write(void *opaque, target_phys_addr_t addr, uint64_t value, unsigned size) { int channel = addr >> DBDMA_CHANNEL_SHIFT; DBDMAState *s = opaque; DBDMA_channel *ch = &s->channels[channel]; int reg = (addr - (channel << DBDMA_CHANNEL_SHIFT)) >> 2; DBDMA_DPRINTF("writel 0x" TARGET_FMT_plx " <= 0x%08x\n", addr, value); DBDMA_DPRINTF("channel 0x%x reg 0x%x\n", (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg); /* cmdptr cannot be modified if channel is RUN or ACTIVE */ if (reg == DBDMA_CMDPTR_LO && (ch->regs[DBDMA_STATUS] & (RUN | ACTIVE))) return; ch->regs[reg] = value; switch(reg) { case DBDMA_CONTROL: dbdma_control_write(ch); break; case DBDMA_CMDPTR_LO: /* 16-byte aligned */ ch->regs[DBDMA_CMDPTR_LO] &= ~0xf; dbdma_cmdptr_load(ch); break; case DBDMA_STATUS: case DBDMA_INTR_SEL: case DBDMA_BRANCH_SEL: case DBDMA_WAIT_SEL: /* nothing to do */ break; case DBDMA_XFER_MODE: case DBDMA_CMDPTR_HI: case DBDMA_DATA2PTR_HI: case DBDMA_DATA2PTR_LO: case DBDMA_ADDRESS_HI: case DBDMA_BRANCH_ADDR_HI: case DBDMA_RES1: case DBDMA_RES2: case DBDMA_RES3: case DBDMA_RES4: /* unused */ break; } } static uint64_t dbdma_read(void *opaque, target_phys_addr_t addr, unsigned size) { uint32_t value; int channel = addr >> DBDMA_CHANNEL_SHIFT; DBDMAState *s = opaque; DBDMA_channel *ch = &s->channels[channel]; int reg = (addr - (channel << DBDMA_CHANNEL_SHIFT)) >> 2; value = ch->regs[reg]; DBDMA_DPRINTF("readl 0x" TARGET_FMT_plx " => 0x%08x\n", addr, value); DBDMA_DPRINTF("channel 0x%x reg 0x%x\n", (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg); switch(reg) { case DBDMA_CONTROL: value = 0; break; case DBDMA_STATUS: case DBDMA_CMDPTR_LO: case DBDMA_INTR_SEL: case DBDMA_BRANCH_SEL: case DBDMA_WAIT_SEL: /* nothing to do */ break; case DBDMA_XFER_MODE: case DBDMA_CMDPTR_HI: case DBDMA_DATA2PTR_HI: case DBDMA_DATA2PTR_LO: case DBDMA_ADDRESS_HI: case DBDMA_BRANCH_ADDR_HI: /* unused */ value = 0; break; case DBDMA_RES1: case DBDMA_RES2: case DBDMA_RES3: case DBDMA_RES4: /* reserved */ break; } return value; } static const MemoryRegionOps dbdma_ops = { .read = dbdma_read, .write = dbdma_write, .endianness = DEVICE_LITTLE_ENDIAN, .valid = { .min_access_size = 4, .max_access_size = 4, }, }; static const VMStateDescription vmstate_dbdma_channel = { .name = "dbdma_channel", .version_id = 0, .minimum_version_id = 0, .minimum_version_id_old = 0, .fields = (VMStateField[]) { VMSTATE_UINT32_ARRAY(regs, struct DBDMA_channel, DBDMA_REGS), VMSTATE_END_OF_LIST() } }; static const VMStateDescription vmstate_dbdma = { .name = "dbdma", .version_id = 2, .minimum_version_id = 2, .minimum_version_id_old = 2, .fields = (VMStateField[]) { VMSTATE_STRUCT_ARRAY(channels, DBDMAState, DBDMA_CHANNELS, 1, vmstate_dbdma_channel, DBDMA_channel), VMSTATE_END_OF_LIST() } }; static void dbdma_reset(void *opaque) { DBDMAState *s = opaque; int i; for (i = 0; i < DBDMA_CHANNELS; i++) memset(s->channels[i].regs, 0, DBDMA_SIZE); } void* DBDMA_init (MemoryRegion **dbdma_mem) { DBDMAState *s; s = g_malloc0(sizeof(DBDMAState)); memory_region_init_io(&s->mem, &dbdma_ops, s, "dbdma", 0x1000); *dbdma_mem = &s->mem; vmstate_register(NULL, -1, &vmstate_dbdma, s); qemu_register_reset(dbdma_reset, s); dbdma_bh = qemu_bh_new(DBDMA_run_bh, s); return s; }