static void omap24xxcam_dmahw_transfer_chain(void __iomem *base, int dmach,
int free_dmach)
{
int prev_dmach, ch;
if (dmach == 0)
prev_dmach = NUM_CAMDMA_CHANNELS - 1;
else
prev_dmach = dmach - 1;
omap24xxcam_reg_out(base, CAMDMA_CLNK_CTRL(prev_dmach),
CAMDMA_CLNK_CTRL_ENABLE_LNK | dmach);
/* Did we chain the DMA transfer before the previous one
* finished?
*/
ch = (dmach + free_dmach) % NUM_CAMDMA_CHANNELS;
while (!(omap24xxcam_reg_in(base, CAMDMA_CCR(ch))
& CAMDMA_CCR_ENABLE)) {
if (ch == dmach) {
/* The previous transfer has ended and this one
* hasn't started, so we must not have chained
* to the previous one in time. We'll have to
* start it now.
*/
omap24xxcam_dmahw_transfer_start(base, dmach);
break;
} else
ch = (ch + 1) % NUM_CAMDMA_CHANNELS;
}
}
/* Start a DMA transfer from the camera to memory.
* Returns zero if the transfer was successfully started, or non-zero if all
* DMA channels are already in use or starting is currently inhibited.
*/
static int omap24xxcam_dma_start(struct omap24xxcam_dma *dma, dma_addr_t start,
u32 len, dma_callback_t callback, void *arg)
{
unsigned long flags;
int dmach;
spin_lock_irqsave(&dma->lock, flags);
if (!dma->free_dmach || atomic_read(&dma->dma_stop)) {
spin_unlock_irqrestore(&dma->lock, flags);
return -EBUSY;
}
dmach = dma->next_dmach;
dma->ch_state[dmach].callback = callback;
dma->ch_state[dmach].arg = arg;
omap24xxcam_dmahw_transfer_setup(dma->base, dmach, start, len);
/* We're ready to start the DMA transfer. */
if (dma->free_dmach < NUM_CAMDMA_CHANNELS) {
/* A transfer is already in progress, so try to chain to it. */
omap24xxcam_dmahw_transfer_chain(dma->base, dmach,
dma->free_dmach);
} else {
/* No transfer is in progress, so we'll just start this one
* now.
*/
omap24xxcam_dmahw_transfer_start(dma->base, dmach);
}
dma->next_dmach = (dma->next_dmach + 1) % NUM_CAMDMA_CHANNELS;
dma->free_dmach--;
spin_unlock_irqrestore(&dma->lock, flags);
return 0;
}
static int omap24xxcam_dma_start(struct omap24xxcam_dma *dma, dma_addr_t start,
u32 len, dma_callback_t callback, void *arg)
{
unsigned long flags;
int dmach;
spin_lock_irqsave(&dma->lock, flags);
if (!dma->free_dmach || atomic_read(&dma->dma_stop)) {
spin_unlock_irqrestore(&dma->lock, flags);
return -EBUSY;
}
dmach = dma->next_dmach;
dma->ch_state[dmach].callback = callback;
dma->ch_state[dmach].arg = arg;
omap24xxcam_dmahw_transfer_setup(dma->base, dmach, start, len);
if (dma->free_dmach < NUM_CAMDMA_CHANNELS) {
omap24xxcam_dmahw_transfer_chain(dma->base, dmach,
dma->free_dmach);
} else {
omap24xxcam_dmahw_transfer_start(dma->base, dmach);
}
dma->next_dmach = (dma->next_dmach + 1) % NUM_CAMDMA_CHANNELS;
dma->free_dmach--;
spin_unlock_irqrestore(&dma->lock, flags);
return 0;
}
static void omap24xxcam_dmahw_transfer_chain(unsigned long base, int dmach,
int free_dmach)
{
int prev_dmach, ch;
if (dmach == 0)
prev_dmach = NUM_CAMDMA_CHANNELS - 1;
else
prev_dmach = dmach - 1;
omap24xxcam_reg_out(base, CAMDMA_CLNK_CTRL(prev_dmach),
CAMDMA_CLNK_CTRL_ENABLE_LNK | dmach);
ch = (dmach + free_dmach) % NUM_CAMDMA_CHANNELS;
while (!(omap24xxcam_reg_in(base, CAMDMA_CCR(ch))
& CAMDMA_CCR_ENABLE)) {
if (ch == dmach) {
omap24xxcam_dmahw_transfer_start(base, dmach);
break;
} else
ch = (ch + 1) % NUM_CAMDMA_CHANNELS;
}
}
