mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-30 13:38:40 +00:00
serial: at91: add tx dma support
Request a slave dma channel for tx dma use. Tx dma will setup a single transfer, when transfer complete, it will call atmel_complete_tx_dma to do finish stuff. Signed-off-by: Elen Song <elen.song@atmel.com> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
a930e52875
commit
08f738be88
@ -143,9 +143,15 @@ struct atmel_uart_port {
|
||||
short pdc_rx_idx; /* current PDC RX buffer */
|
||||
struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
|
||||
|
||||
bool use_dma_tx; /* enable DMA transmitter */
|
||||
bool use_pdc_tx; /* enable PDC transmitter */
|
||||
struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
|
||||
|
||||
spinlock_t lock_tx; /* port lock */
|
||||
struct dma_chan *chan_tx;
|
||||
struct dma_async_tx_descriptor *desc_tx;
|
||||
dma_cookie_t cookie_tx;
|
||||
struct scatterlist sg_tx;
|
||||
struct tasklet_struct tasklet;
|
||||
unsigned int irq_status;
|
||||
unsigned int irq_status_prev;
|
||||
@ -211,6 +217,13 @@ static bool atmel_use_pdc_tx(struct uart_port *port)
|
||||
}
|
||||
#endif
|
||||
|
||||
static bool atmel_use_dma_tx(struct uart_port *port)
|
||||
{
|
||||
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
|
||||
|
||||
return atmel_port->use_dma_tx;
|
||||
}
|
||||
|
||||
/* Enable or disable the rs485 support */
|
||||
void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
|
||||
{
|
||||
@ -569,6 +582,182 @@ static void atmel_tx_chars(struct uart_port *port)
|
||||
UART_PUT_IER(port, atmel_port->tx_done_mask);
|
||||
}
|
||||
|
||||
static void atmel_complete_tx_dma(void *arg)
|
||||
{
|
||||
struct atmel_uart_port *atmel_port = arg;
|
||||
struct uart_port *port = &atmel_port->uart;
|
||||
struct circ_buf *xmit = &port->state->xmit;
|
||||
struct dma_chan *chan = atmel_port->chan_tx;
|
||||
unsigned long flags;
|
||||
|
||||
spin_lock_irqsave(&port->lock, flags);
|
||||
|
||||
if (chan)
|
||||
dmaengine_terminate_all(chan);
|
||||
xmit->tail += sg_dma_len(&atmel_port->sg_tx);
|
||||
xmit->tail &= UART_XMIT_SIZE - 1;
|
||||
|
||||
port->icount.tx += sg_dma_len(&atmel_port->sg_tx);
|
||||
|
||||
spin_lock_irq(&atmel_port->lock_tx);
|
||||
async_tx_ack(atmel_port->desc_tx);
|
||||
atmel_port->cookie_tx = -EINVAL;
|
||||
atmel_port->desc_tx = NULL;
|
||||
spin_unlock_irq(&atmel_port->lock_tx);
|
||||
|
||||
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
|
||||
uart_write_wakeup(port);
|
||||
|
||||
/* Do we really need this? */
|
||||
if (!uart_circ_empty(xmit))
|
||||
tasklet_schedule(&atmel_port->tasklet);
|
||||
|
||||
spin_unlock_irqrestore(&port->lock, flags);
|
||||
}
|
||||
|
||||
static void atmel_release_tx_dma(struct uart_port *port)
|
||||
{
|
||||
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
|
||||
struct dma_chan *chan = atmel_port->chan_tx;
|
||||
|
||||
if (chan) {
|
||||
dmaengine_terminate_all(chan);
|
||||
dma_release_channel(chan);
|
||||
dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1,
|
||||
DMA_MEM_TO_DEV);
|
||||
}
|
||||
|
||||
atmel_port->desc_tx = NULL;
|
||||
atmel_port->chan_tx = NULL;
|
||||
atmel_port->cookie_tx = -EINVAL;
|
||||
}
|
||||
|
||||
/*
|
||||
* Called from tasklet with TXRDY interrupt is disabled.
|
||||
*/
|
||||
static void atmel_tx_dma(struct uart_port *port)
|
||||
{
|
||||
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
|
||||
struct circ_buf *xmit = &port->state->xmit;
|
||||
struct dma_chan *chan = atmel_port->chan_tx;
|
||||
struct dma_async_tx_descriptor *desc;
|
||||
struct scatterlist *sg = &atmel_port->sg_tx;
|
||||
|
||||
/* Make sure we have an idle channel */
|
||||
if (atmel_port->desc_tx != NULL)
|
||||
return;
|
||||
|
||||
if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
|
||||
/*
|
||||
* DMA is idle now.
|
||||
* Port xmit buffer is already mapped,
|
||||
* and it is one page... Just adjust
|
||||
* offsets and lengths. Since it is a circular buffer,
|
||||
* we have to transmit till the end, and then the rest.
|
||||
* Take the port lock to get a
|
||||
* consistent xmit buffer state.
|
||||
*/
|
||||
sg->offset = xmit->tail & (UART_XMIT_SIZE - 1);
|
||||
sg_dma_address(sg) = (sg_dma_address(sg) &
|
||||
~(UART_XMIT_SIZE - 1))
|
||||
+ sg->offset;
|
||||
sg_dma_len(sg) = CIRC_CNT_TO_END(xmit->head,
|
||||
xmit->tail,
|
||||
UART_XMIT_SIZE);
|
||||
BUG_ON(!sg_dma_len(sg));
|
||||
|
||||
desc = dmaengine_prep_slave_sg(chan,
|
||||
sg,
|
||||
1,
|
||||
DMA_MEM_TO_DEV,
|
||||
DMA_PREP_INTERRUPT |
|
||||
DMA_CTRL_ACK);
|
||||
if (!desc) {
|
||||
dev_err(port->dev, "Failed to send via dma!\n");
|
||||
return;
|
||||
}
|
||||
|
||||
dma_sync_sg_for_device(port->dev, sg, 1, DMA_MEM_TO_DEV);
|
||||
|
||||
atmel_port->desc_tx = desc;
|
||||
desc->callback = atmel_complete_tx_dma;
|
||||
desc->callback_param = atmel_port;
|
||||
atmel_port->cookie_tx = dmaengine_submit(desc);
|
||||
|
||||
} else {
|
||||
if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
|
||||
/* DMA done, stop TX, start RX for RS485 */
|
||||
atmel_start_rx(port);
|
||||
}
|
||||
}
|
||||
|
||||
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
|
||||
uart_write_wakeup(port);
|
||||
}
|
||||
|
||||
static int atmel_prepare_tx_dma(struct uart_port *port)
|
||||
{
|
||||
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
|
||||
dma_cap_mask_t mask;
|
||||
struct dma_slave_config config;
|
||||
int ret, nent;
|
||||
|
||||
dma_cap_zero(mask);
|
||||
dma_cap_set(DMA_SLAVE, mask);
|
||||
|
||||
atmel_port->chan_tx = dma_request_slave_channel(port->dev, "tx");
|
||||
if (atmel_port->chan_tx == NULL)
|
||||
goto chan_err;
|
||||
dev_info(port->dev, "using %s for tx DMA transfers\n",
|
||||
dma_chan_name(atmel_port->chan_tx));
|
||||
|
||||
spin_lock_init(&atmel_port->lock_tx);
|
||||
sg_init_table(&atmel_port->sg_tx, 1);
|
||||
/* UART circular tx buffer is an aligned page. */
|
||||
BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK);
|
||||
sg_set_page(&atmel_port->sg_tx,
|
||||
virt_to_page(port->state->xmit.buf),
|
||||
UART_XMIT_SIZE,
|
||||
(int)port->state->xmit.buf & ~PAGE_MASK);
|
||||
nent = dma_map_sg(port->dev,
|
||||
&atmel_port->sg_tx,
|
||||
1,
|
||||
DMA_MEM_TO_DEV);
|
||||
|
||||
if (!nent) {
|
||||
dev_dbg(port->dev, "need to release resource of dma\n");
|
||||
goto chan_err;
|
||||
} else {
|
||||
dev_dbg(port->dev, "%s: mapped %d@%p to %x\n", __func__,
|
||||
sg_dma_len(&atmel_port->sg_tx),
|
||||
port->state->xmit.buf,
|
||||
sg_dma_address(&atmel_port->sg_tx));
|
||||
}
|
||||
|
||||
/* Configure the slave DMA */
|
||||
memset(&config, 0, sizeof(config));
|
||||
config.direction = DMA_MEM_TO_DEV;
|
||||
config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
|
||||
config.dst_addr = port->mapbase + ATMEL_US_THR;
|
||||
|
||||
ret = dmaengine_device_control(atmel_port->chan_tx,
|
||||
DMA_SLAVE_CONFIG,
|
||||
(unsigned long)&config);
|
||||
if (ret) {
|
||||
dev_err(port->dev, "DMA tx slave configuration failed\n");
|
||||
goto chan_err;
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
chan_err:
|
||||
dev_err(port->dev, "TX channel not available, switch to pio\n");
|
||||
atmel_port->use_dma_tx = 0;
|
||||
if (atmel_port->chan_tx)
|
||||
atmel_release_tx_dma(port);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/*
|
||||
* receive interrupt handler.
|
||||
*/
|
||||
@ -997,7 +1186,11 @@ static void atmel_set_ops(struct uart_port *port)
|
||||
atmel_port->release_rx = NULL;
|
||||
}
|
||||
|
||||
if (atmel_use_pdc_tx(port)) {
|
||||
if (atmel_use_dma_tx(port)) {
|
||||
atmel_port->prepare_tx = &atmel_prepare_tx_dma;
|
||||
atmel_port->schedule_tx = &atmel_tx_dma;
|
||||
atmel_port->release_tx = &atmel_release_tx_dma;
|
||||
} else if (atmel_use_pdc_tx(port)) {
|
||||
atmel_port->prepare_tx = &atmel_prepare_tx_pdc;
|
||||
atmel_port->schedule_tx = &atmel_tx_pdc;
|
||||
atmel_port->release_tx = &atmel_release_tx_pdc;
|
||||
@ -1488,10 +1681,18 @@ static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
|
||||
else
|
||||
atmel_port->use_pdc_rx = false;
|
||||
|
||||
if (of_get_property(np, "atmel,use-dma-tx", NULL))
|
||||
atmel_port->use_pdc_tx = true;
|
||||
else
|
||||
if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
|
||||
if (of_get_property(np, "dmas", NULL)) {
|
||||
atmel_port->use_dma_tx = true;
|
||||
atmel_port->use_pdc_tx = false;
|
||||
} else {
|
||||
atmel_port->use_dma_tx = false;
|
||||
atmel_port->use_pdc_tx = true;
|
||||
}
|
||||
} else {
|
||||
atmel_port->use_dma_tx = false;
|
||||
atmel_port->use_pdc_tx = false;
|
||||
}
|
||||
|
||||
/* rs485 properties */
|
||||
if (of_property_read_u32_array(np, "rs485-rts-delay",
|
||||
@ -1525,6 +1726,7 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
|
||||
} else {
|
||||
atmel_port->use_pdc_rx = pdata->use_dma_rx;
|
||||
atmel_port->use_pdc_tx = pdata->use_dma_tx;
|
||||
atmel_port->use_dma_tx = false;
|
||||
atmel_port->rs485 = pdata->rs485;
|
||||
}
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user