/*

* DMA helper functions

*

* Copyright (c) 2009 Red Hat

*

* This work is licensed under the terms of the GNU General Public License

* (GNU GPL), version 2 or later.

*/

#include "dma.h"

#include "block_int.h"

void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)

{

qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry));

qsg->nsg = 0;

qsg->nalloc = alloc_hint;

qsg->size = 0;

}

void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,

target_phys_addr_t len)

{

if (qsg->nsg == qsg->nalloc) {

qsg->nalloc = 2 * qsg->nalloc + 1;

qsg->sg = qemu_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));

}

qsg->sg[qsg->nsg].base = base;

qsg->sg[qsg->nsg].len = len;

qsg->size += len;

++qsg->nsg;

}

void qemu_sglist_destroy(QEMUSGList *qsg)

{

qemu_free(qsg->sg);

}

typedef struct {

BlockDriverAIOCB common;

BlockDriverState *bs;

BlockDriverAIOCB *acb;

QEMUSGList *sg;

uint64_t sector_num;

int is_write;

int sg_cur_index;

target_phys_addr_t sg_cur_byte;

QEMUIOVector iov;

QEMUBH *bh;

} DMAAIOCB;

static void dma_bdrv_cb(void *opaque, int ret);

static void reschedule_dma(void *opaque)

{

DMAAIOCB *dbs = (DMAAIOCB *)opaque;

qemu_bh_delete(dbs->bh);

dbs->bh = NULL;

dma_bdrv_cb(opaque, 0);

}

static void continue_after_map_failure(void *opaque)

{

DMAAIOCB *dbs = (DMAAIOCB *)opaque;

dbs->bh = qemu_bh_new(reschedule_dma, dbs);

qemu_bh_schedule(dbs->bh);

}

static void dma_bdrv_unmap(DMAAIOCB *dbs)

{

int i;

for (i = 0; i < dbs->iov.niov; ++i) {

cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base,

dbs->iov.iov[i].iov_len, !dbs->is_write,

dbs->iov.iov[i].iov_len);

}

}

static void dma_bdrv_cb(void *opaque, int ret)

{

DMAAIOCB *dbs = (DMAAIOCB *)opaque;

target_phys_addr_t cur_addr, cur_len;

void *mem;

dbs->acb = NULL;

dbs->sector_num += dbs->iov.size / 512;

dma_bdrv_unmap(dbs);

qemu_iovec_reset(&dbs->iov);

if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {

dbs->common.cb(dbs->common.opaque, ret);

qemu_iovec_destroy(&dbs->iov);

qemu_aio_release(dbs);

return;

}

while (dbs->sg_cur_index < dbs->sg->nsg) {

cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;

cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;

mem = cpu_physical_memory_map(cur_addr, &cur_len, !dbs->is_write);

if (!mem)

break;

qemu_iovec_add(&dbs->iov, mem, cur_len);

dbs->sg_cur_byte += cur_len;

if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {

dbs->sg_cur_byte = 0;

++dbs->sg_cur_index;

}

}

if (dbs->iov.size == 0) {

cpu_register_map_client(dbs, continue_after_map_failure);

return;

}

if (dbs->is_write) {

dbs->acb = bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov,

dbs->iov.size / 512, dma_bdrv_cb, dbs);

} else {

dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov,

dbs->iov.size / 512, dma_bdrv_cb, dbs);

}

if (!dbs->acb) {

dma_bdrv_unmap(dbs);

qemu_iovec_destroy(&dbs->iov);

return;

}

}

static void dma_aio_cancel(BlockDriverAIOCB *acb)

{

DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);

if (dbs->acb) {

bdrv_aio_cancel(dbs->acb);

}

}

static AIOPool dma_aio_pool = {

.aiocb_size = sizeof(DMAAIOCB),

.cancel = dma_aio_cancel,

};

static BlockDriverAIOCB *dma_bdrv_io(

BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,

BlockDriverCompletionFunc *cb, void *opaque,

int is_write)

{

DMAAIOCB *dbs = qemu_aio_get(&dma_aio_pool, bs, cb, opaque);

dbs->acb = NULL;

dbs->bs = bs;

dbs->sg = sg;

dbs->sector_num = sector_num;

dbs->sg_cur_index = 0;

dbs->sg_cur_byte = 0;

dbs->is_write = is_write;

dbs->bh = NULL;

qemu_iovec_init(&dbs->iov, sg->nsg);

dma_bdrv_cb(dbs, 0);

if (!dbs->acb) {

qemu_aio_release(dbs);

return NULL;

}

return &dbs->common;

}

BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,

QEMUSGList *sg, uint64_t sector,

void (*cb)(void *opaque, int ret), void *opaque)

{

return dma_bdrv_io(bs, sg, sector, cb, opaque, 0);

}

BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,

QEMUSGList *sg, uint64_t sector,

void (*cb)(void *opaque, int ret), void *opaque)

{

return dma_bdrv_io(bs, sg, sector, cb, opaque, 1);

}