/**
* snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
* @substream: PCM substream
* @cmd: Trigger command
*
* Returns 0 on success, a negative error code otherwise.
*
* This function can be used as the PCM trigger callback for dmaengine based PCM
* driver implementations.
*/
int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
int ret;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
ret = dmaengine_pcm_prepare_and_submit(substream);
if (ret)
return ret;
dma_async_issue_pending(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
dmaengine_resume(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
dmaengine_pause(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_STOP:
dmaengine_terminate_all(prtd->dma_chan);
break;
default:
return -EINVAL;
}
return 0;
}
static void sirfsoc_uart_tx_with_dma(struct sirfsoc_uart_port *sirfport)
{
struct uart_port *port = &sirfport->port;
struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
struct circ_buf *xmit = &port->state->xmit;
unsigned long tran_size;
unsigned long tran_start;
unsigned long pio_tx_size;
tran_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
tran_start = (unsigned long)(xmit->buf + xmit->tail);
if (uart_circ_empty(xmit) || uart_tx_stopped(port) ||
!tran_size)
return;
if (sirfport->tx_dma_state == TX_DMA_PAUSE) {
dmaengine_resume(sirfport->tx_dma_chan);
return;
}
if (sirfport->tx_dma_state == TX_DMA_RUNNING)
return;
if (!sirfport->is_atlas7)
wr_regl(port, ureg->sirfsoc_int_en_reg,
rd_regl(port, ureg->sirfsoc_int_en_reg)&
~(uint_en->sirfsoc_txfifo_empty_en));
else
wr_regl(port, SIRFUART_INT_EN_CLR,
uint_en->sirfsoc_txfifo_empty_en);
/*
* DMA requires buffer address and buffer length are both aligned with
* 4 bytes, so we use PIO for
* 1. if address is not aligned with 4bytes, use PIO for the first 1~3
* bytes, and move to DMA for the left part aligned with 4bytes
* 2. if buffer length is not aligned with 4bytes, use DMA for aligned
* part first, move to PIO for the left 1~3 bytes
*/
if (tran_size < 4 || BYTES_TO_ALIGN(tran_start)) {
wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_STOP);
wr_regl(port, ureg->sirfsoc_tx_dma_io_ctrl,
rd_regl(port, ureg->sirfsoc_tx_dma_io_ctrl)|
SIRFUART_IO_MODE);
if (BYTES_TO_ALIGN(tran_start)) {
pio_tx_size = sirfsoc_uart_pio_tx_chars(sirfport,
BYTES_TO_ALIGN(tran_start));
tran_size -= pio_tx_size;
}
if (tran_size < 4)
sirfsoc_uart_pio_tx_chars(sirfport, tran_size);
if (!sirfport->is_atlas7)
wr_regl(port, ureg->sirfsoc_int_en_reg,
rd_regl(port, ureg->sirfsoc_int_en_reg)|
uint_en->sirfsoc_txfifo_empty_en);
else
wr_regl(port, ureg->sirfsoc_int_en_reg,
uint_en->sirfsoc_txfifo_empty_en);
wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_START);
} else {
/* tx transfer mode switch into dma mode */
wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_STOP);
wr_regl(port, ureg->sirfsoc_tx_dma_io_ctrl,
rd_regl(port, ureg->sirfsoc_tx_dma_io_ctrl)&
~SIRFUART_IO_MODE);
wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_START);
tran_size &= ~(0x3);
sirfport->tx_dma_addr = dma_map_single(port->dev,
xmit->buf + xmit->tail,
tran_size, DMA_TO_DEVICE);
sirfport->tx_dma_desc = dmaengine_prep_slave_single(
sirfport->tx_dma_chan, sirfport->tx_dma_addr,
tran_size, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
if (!sirfport->tx_dma_desc) {
dev_err(port->dev, "DMA prep slave single fail\n");
return;
}
sirfport->tx_dma_desc->callback =
sirfsoc_uart_tx_dma_complete_callback;
sirfport->tx_dma_desc->callback_param = (void *)sirfport;
sirfport->transfer_size = tran_size;
dmaengine_submit(sirfport->tx_dma_desc);
dma_async_issue_pending(sirfport->tx_dma_chan);
sirfport->tx_dma_state = TX_DMA_RUNNING;
}
}
static enum hrtimer_restart
sirfsoc_uart_rx_dma_hrtimer_callback(struct hrtimer *hrt)
{
struct sirfsoc_uart_port *sirfport;
struct uart_port *port;
int count, inserted;
struct dma_tx_state tx_state;
struct tty_struct *tty;
struct sirfsoc_register *ureg;
struct circ_buf *xmit;
struct sirfsoc_fifo_status *ufifo_st;
int max_pio_cnt;
sirfport = container_of(hrt, struct sirfsoc_uart_port, hrt);
port = &sirfport->port;
inserted = 0;
tty = port->state->port.tty;
ureg = &sirfport->uart_reg->uart_reg;
xmit = &sirfport->rx_dma_items.xmit;
ufifo_st = &sirfport->uart_reg->fifo_status;
dmaengine_tx_status(sirfport->rx_dma_chan,
sirfport->rx_dma_items.cookie, &tx_state);
if (SIRFSOC_RX_DMA_BUF_SIZE - tx_state.residue !=
sirfport->rx_last_pos) {
xmit->head = SIRFSOC_RX_DMA_BUF_SIZE - tx_state.residue;
sirfport->rx_last_pos = xmit->head;
sirfport->pio_fetch_cnt = 0;
}
count = CIRC_CNT_TO_END(xmit->head, xmit->tail,
SIRFSOC_RX_DMA_BUF_SIZE);
while (count > 0) {
inserted = tty_insert_flip_string(tty->port,
(const unsigned char *)&xmit->buf[xmit->tail], count);
if (!inserted)
goto next_hrt;
port->icount.rx += inserted;
xmit->tail = (xmit->tail + inserted) &
(SIRFSOC_RX_DMA_BUF_SIZE - 1);
count = CIRC_CNT_TO_END(xmit->head, xmit->tail,
SIRFSOC_RX_DMA_BUF_SIZE);
tty_flip_buffer_push(tty->port);
}
/*
* if RX DMA buffer data have all push into tty buffer, and there is
* only little data(less than a dma transfer unit) left in rxfifo,
* fetch it out in pio mode and switch back to dma immediately
*/
if (!inserted && !count &&
((rd_regl(port, ureg->sirfsoc_rx_fifo_status) &
SIRFUART_RX_FIFO_MASK) > sirfport->pio_fetch_cnt)) {
dmaengine_pause(sirfport->rx_dma_chan);
/* switch to pio mode */
wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) |
SIRFUART_IO_MODE);
/*
* UART controller SWH_DMA_IO register have CLEAR_RX_ADDR_EN
* When found changing I/O to DMA mode, it clears
* two low bits of read point;
* USP have similar FRADDR_CLR_EN bit in USP_RX_DMA_IO_CTRL.
* Fetch data out from rxfifo into DMA buffer in PIO mode,
* while switch back to DMA mode, the data fetched will override
* by DMA, as hardware have a strange behaviour:
* after switch back to DMA mode, check rxfifo status it will
* be the number PIO fetched, so record the fetched data count
* to avoid the repeated fetch
*/
max_pio_cnt = 3;
while (!(rd_regl(port, ureg->sirfsoc_rx_fifo_status) &
ufifo_st->ff_empty(port)) && max_pio_cnt--) {
xmit->buf[xmit->head] =
rd_regl(port, ureg->sirfsoc_rx_fifo_data);
xmit->head = (xmit->head + 1) &
(SIRFSOC_RX_DMA_BUF_SIZE - 1);
sirfport->pio_fetch_cnt++;
}
/* switch back to dma mode */
wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) &
~SIRFUART_IO_MODE);
dmaengine_resume(sirfport->rx_dma_chan);
}
next_hrt:
hrtimer_forward_now(hrt, ns_to_ktime(sirfport->rx_period_time));
return HRTIMER_RESTART;
}
