/**
* sg_next - return the next scatterlist entry in a list
* @sg: The current sg entry
*
* Description:
* Usually the next entry will be @sg@ + 1, but if this sg element is part
* of a chained scatterlist, it could jump to the start of a new
* scatterlist array.
*
**/
struct scatterlist *sg_next(struct scatterlist *sg)
{
#ifdef CONFIG_DEBUG_SG
BUG_ON(sg->sg_magic != SG_MAGIC);
#endif
if (sg_is_last(sg))
return NULL;
sg++;
if (unlikely(sg_is_chain(sg)))
sg = sg_chain_ptr(sg);
return sg;
}
static int sg_count_ents(struct scatterlist *sg_list, int nbytes, int *lbytes)
{
int nents = 0;
while (nbytes > 0) {
if (sg_is_chain(sg_list)) {
DX_LOG_ERR("Unexpected chanined entry "
"in sg (entry =0x%X) \n", nents);
BUG();
}
nents++;
/* get the number of bytes in the last entry */
*lbytes = nbytes;
nbytes -= sg_list->length;
sg_list = sg_next(sg_list);
}
DX_LOG_DEBUG("nents %d last bytes %d\n",nents, *lbytes);
return nents;
}
int
coh901318_lli_fill_sg(struct coh901318_pool *pool,
struct coh901318_lli *lli,
struct scatterlist *sgl, unsigned int nents,
dma_addr_t dev_addr, u32 ctrl_chained, u32 ctrl,
u32 ctrl_last,
enum dma_data_direction dir, u32 ctrl_irq_mask)
{
int i;
struct scatterlist *sg;
u32 ctrl_sg;
dma_addr_t src = 0;
dma_addr_t dst = 0;
u32 bytes_to_transfer;
u32 elem_size;
if (lli == NULL)
goto err;
spin_lock(&pool->lock);
if (dir == DMA_TO_DEVICE)
dst = dev_addr;
else if (dir == DMA_FROM_DEVICE)
src = dev_addr;
else
goto err;
for_each_sg(sgl, sg, nents, i) {
if (sg_is_chain(sg)) {
/* sg continues to the next sg-element don't
* send ctrl_finish until the last
* sg-element in the chain
*/
ctrl_sg = ctrl_chained;
} else if (i == nents - 1)
ctrl_sg = ctrl_last;
else
ctrl_sg = ctrl ? ctrl : ctrl_last;
if (dir == DMA_TO_DEVICE)
/* increment source address */
src = sg_phys(sg);
else
/* increment destination address */
dst = sg_phys(sg);
bytes_to_transfer = sg_dma_len(sg);
while (bytes_to_transfer) {
u32 val;
if (bytes_to_transfer > MAX_DMA_PACKET_SIZE) {
elem_size = MAX_DMA_PACKET_SIZE;
val = ctrl_chained;
} else {
elem_size = bytes_to_transfer;
val = ctrl_sg;
}
lli->control = val | elem_size;
lli->src_addr = src;
lli->dst_addr = dst;
if (dir == DMA_FROM_DEVICE)
dst += elem_size;
else
src += elem_size;
BUG_ON(lli->link_addr & 3);
bytes_to_transfer -= elem_size;
lli = coh901318_lli_next(lli);
}
}
spin_unlock(&pool->lock);
return 0;
err:
spin_unlock(&pool->lock);
return -EINVAL;
}
