/*
* hsu_dma_do_irq() - DMA interrupt handler
* @chip: HSUART DMA chip
* @nr: DMA channel number
* @status: Channel Status Register value
*
* Description:
* This function handles Channel Error and Descriptor Done interrupts.
* This function should be called after determining that the DMA interrupt
* is not a normal timeout interrupt, ie. hsu_dma_get_status() returned 0.
*
* Return:
* 0 for invalid channel number, 1 otherwise.
*/
int hsu_dma_do_irq(struct hsu_dma_chip *chip, unsigned short nr, u32 status)
{
struct hsu_dma_chan *hsuc;
struct hsu_dma_desc *desc;
unsigned long flags;
/* Sanity check */
if (nr >= chip->hsu->nr_channels)
return 0;
hsuc = &chip->hsu->chan[nr];
spin_lock_irqsave(&hsuc->vchan.lock, flags);
desc = hsuc->desc;
if (desc) {
if (status & HSU_CH_SR_CHE) {
desc->status = DMA_ERROR;
} else if (desc->active < desc->nents) {
hsu_dma_start_channel(hsuc);
} else {
vchan_cookie_complete(&desc->vdesc);
desc->status = DMA_COMPLETE;
hsu_dma_start_transfer(hsuc);
}
}
spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
return 1;
}
irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr)
{
struct hsu_dma_chan *hsuc;
struct hsu_dma_desc *desc;
unsigned long flags;
u32 sr;
/* Sanity check */
if (nr >= chip->hsu->nr_channels)
return IRQ_NONE;
hsuc = &chip->hsu->chan[nr];
/*
* No matter what situation, need read clear the IRQ status
* There is a bug, see Errata 5, HSD 2900918
*/
sr = hsu_dma_chan_get_sr(hsuc);
if (!sr)
return IRQ_NONE;
/* Timeout IRQ, need wait some time, see Errata 2 */
if (hsuc->direction == DMA_DEV_TO_MEM && (sr & HSU_CH_SR_DESCTO_ANY))
udelay(2);
sr &= ~HSU_CH_SR_DESCTO_ANY;
if (!sr)
return IRQ_HANDLED;
spin_lock_irqsave(&hsuc->vchan.lock, flags);
desc = hsuc->desc;
if (desc) {
if (sr & HSU_CH_SR_CHE) {
desc->status = DMA_ERROR;
} else if (desc->active < desc->nents) {
hsu_dma_start_channel(hsuc);
} else {
vchan_cookie_complete(&desc->vdesc);
desc->status = DMA_COMPLETE;
hsu_dma_start_transfer(hsuc);
}
}
spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
return IRQ_HANDLED;
}
static void hsu_dma_start_transfer(struct hsu_dma_chan *hsuc)
{
struct virt_dma_desc *vdesc;
/* Get the next descriptor */
vdesc = vchan_next_desc(&hsuc->vchan);
if (!vdesc) {
hsuc->desc = NULL;
return;
}
list_del(&vdesc->node);
hsuc->desc = to_hsu_dma_desc(vdesc);
/* Start the channel with a new descriptor */
hsu_dma_start_channel(hsuc);
}
