diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 13c1d3170119e848be2c46147c5b59742b4a33cb..eaf7dc7795b8500391f73085b9f94ff1ea257de4 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -139,6 +139,7 @@ struct atmel_uart_port {
u32 backup_imr; /* IMR saved during suspend */
int break_active; /* break being received */
+ bool use_dma_rx; /* enable DMA receiver */
bool use_pdc_rx; /* enable PDC receiver */
short pdc_rx_idx; /* current PDC RX buffer */
struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
@@ -148,10 +149,15 @@ struct atmel_uart_port {
struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
spinlock_t lock_tx; /* port lock */
+ spinlock_t lock_rx; /* port lock */
struct dma_chan *chan_tx;
+ struct dma_chan *chan_rx;
struct dma_async_tx_descriptor *desc_tx;
+ struct dma_async_tx_descriptor *desc_rx;
dma_cookie_t cookie_tx;
+ dma_cookie_t cookie_rx;
struct scatterlist sg_tx;
+ struct scatterlist sg_rx;
struct tasklet_struct tasklet;
unsigned int irq_status;
unsigned int irq_status_prev;
@@ -224,6 +230,13 @@ static bool atmel_use_dma_tx(struct uart_port *port)
return atmel_port->use_dma_tx;
}
+static bool atmel_use_dma_rx(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+ return atmel_port->use_dma_rx;
+}
+
/* Enable or disable the rs485 support */
void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
{
@@ -758,6 +771,184 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
return -EINVAL;
}
+static void atmel_flip_buffer_rx_dma(struct uart_port *port,
+ char *buf, size_t count)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ struct tty_port *tport = &port->state->port;
+
+ dma_sync_sg_for_cpu(port->dev,
+ &atmel_port->sg_rx,
+ 1,
+ DMA_DEV_TO_MEM);
+
+ tty_insert_flip_string(tport, buf, count);
+
+ dma_sync_sg_for_device(port->dev,
+ &atmel_port->sg_rx,
+ 1,
+ DMA_DEV_TO_MEM);
+ /*
+ * Drop the lock here since it might end up calling
+ * uart_start(), which takes the lock.
+ */
+ spin_unlock(&port->lock);
+ tty_flip_buffer_push(tport);
+ spin_lock(&port->lock);
+}
+
+static void atmel_complete_rx_dma(void *arg)
+{
+ struct uart_port *port = arg;
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+ tasklet_schedule(&atmel_port->tasklet);
+}
+
+static void atmel_release_rx_dma(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ struct dma_chan *chan = atmel_port->chan_rx;
+
+ if (chan) {
+ dmaengine_terminate_all(chan);
+ dma_release_channel(chan);
+ dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1,
+ DMA_DEV_TO_MEM);
+ }
+
+ atmel_port->desc_rx = NULL;
+ atmel_port->chan_rx = NULL;
+ atmel_port->cookie_rx = -EINVAL;
+}
+
+static void atmel_rx_from_dma(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ struct circ_buf *ring = &atmel_port->rx_ring;
+ struct dma_chan *chan = atmel_port->chan_rx;
+ struct dma_tx_state state;
+ enum dma_status dmastat;
+ size_t pending, count;
+
+
+ /* Reset the UART timeout early so that we don't miss one */
+ UART_PUT_CR(port, ATMEL_US_STTTO);
+ dmastat = dmaengine_tx_status(chan,
+ atmel_port->cookie_rx,
+ &state);
+ /* Restart a new tasklet if DMA status is error */
+ if (dmastat == DMA_ERROR) {
+ dev_dbg(port->dev, "Get residue error, restart tasklet\n");
+ UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+ tasklet_schedule(&atmel_port->tasklet);
+ return;
+ }
+ /* current transfer size should no larger than dma buffer */
+ pending = sg_dma_len(&atmel_port->sg_rx) - state.residue;
+ BUG_ON(pending > sg_dma_len(&atmel_port->sg_rx));
+
+ /*
+ * This will take the chars we have so far,
+ * ring->head will record the transfer size, only new bytes come
+ * will insert into the framework.
+ */
+ if (pending > ring->head) {
+ count = pending - ring->head;
+
+ atmel_flip_buffer_rx_dma(port, ring->buf + ring->head, count);
+
+ ring->head += count;
+ if (ring->head == sg_dma_len(&atmel_port->sg_rx))
+ ring->head = 0;
+
+ port->icount.rx += count;
+ }
+
+ UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+}
+
+static int atmel_prepare_rx_dma(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ struct dma_async_tx_descriptor *desc;
+ dma_cap_mask_t mask;
+ struct dma_slave_config config;
+ struct circ_buf *ring;
+ int ret, nent;
+
+ ring = &atmel_port->rx_ring;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_CYCLIC, mask);
+
+ atmel_port->chan_rx = dma_request_slave_channel(port->dev, "rx");
+ if (atmel_port->chan_rx == NULL)
+ goto chan_err;
+ dev_info(port->dev, "using %s for rx DMA transfers\n",
+ dma_chan_name(atmel_port->chan_rx));
+
+ spin_lock_init(&atmel_port->lock_rx);
+ sg_init_table(&atmel_port->sg_rx, 1);
+ /* UART circular rx buffer is an aligned page. */
+ BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK);
+ sg_set_page(&atmel_port->sg_rx,
+ virt_to_page(ring->buf),
+ ATMEL_SERIAL_RINGSIZE,
+ (int)ring->buf & ~PAGE_MASK);
+ nent = dma_map_sg(port->dev,
+ &atmel_port->sg_rx,
+ 1,
+ DMA_DEV_TO_MEM);
+
+ 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_rx),
+ ring->buf,
+ sg_dma_address(&atmel_port->sg_rx));
+ }
+
+ /* Configure the slave DMA */
+ memset(&config, 0, sizeof(config));
+ config.direction = DMA_DEV_TO_MEM;
+ config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ config.src_addr = port->mapbase + ATMEL_US_RHR;
+
+ ret = dmaengine_device_control(atmel_port->chan_rx,
+ DMA_SLAVE_CONFIG,
+ (unsigned long)&config);
+ if (ret) {
+ dev_err(port->dev, "DMA rx slave configuration failed\n");
+ goto chan_err;
+ }
+ /*
+ * Prepare a cyclic dma transfer, assign 2 descriptors,
+ * each one is half ring buffer size
+ */
+ desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx,
+ sg_dma_address(&atmel_port->sg_rx),
+ sg_dma_len(&atmel_port->sg_rx),
+ sg_dma_len(&atmel_port->sg_rx)/2,
+ DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT);
+ desc->callback = atmel_complete_rx_dma;
+ desc->callback_param = port;
+ atmel_port->desc_rx = desc;
+ atmel_port->cookie_rx = dmaengine_submit(desc);
+
+ return 0;
+
+chan_err:
+ dev_err(port->dev, "RX channel not available, switch to pio\n");
+ atmel_port->use_dma_rx = 0;
+ if (atmel_port->chan_rx)
+ atmel_release_rx_dma(port);
+ return -EINVAL;
+}
+
/*
* receive interrupt handler.
*/
@@ -785,6 +976,13 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
atmel_pdc_rxerr(port, pending);
}
+ if (atmel_use_dma_rx(port)) {
+ if (pending & ATMEL_US_TIMEOUT) {
+ UART_PUT_IDR(port, ATMEL_US_TIMEOUT);
+ tasklet_schedule(&atmel_port->tasklet);
+ }
+ }
+
/* Interrupt receive */
if (pending & ATMEL_US_RXRDY)
atmel_rx_chars(port);
@@ -1176,7 +1374,11 @@ static void atmel_set_ops(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- if (atmel_use_pdc_rx(port)) {
+ if (atmel_use_dma_rx(port)) {
+ atmel_port->prepare_rx = &atmel_prepare_rx_dma;
+ atmel_port->schedule_rx = &atmel_rx_from_dma;
+ atmel_port->release_rx = &atmel_release_rx_dma;
+ } else if (atmel_use_pdc_rx(port)) {
atmel_port->prepare_rx = &atmel_prepare_rx_pdc;
atmel_port->schedule_rx = &atmel_rx_from_pdc;
atmel_port->release_rx = &atmel_release_rx_pdc;
@@ -1272,6 +1474,11 @@ static int atmel_startup(struct uart_port *port)
UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
/* enable PDC controller */
UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
+ } else if (atmel_use_dma_rx(port)) {
+ UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
+ UART_PUT_CR(port, ATMEL_US_STTTO);
+
+ UART_PUT_IER(port, ATMEL_US_TIMEOUT);
} else {
/* enable receive only */
UART_PUT_IER(port, ATMEL_US_RXRDY);
@@ -1676,10 +1883,18 @@ static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
u32 rs485_delay[2];
/* DMA/PDC usage specification */
- if (of_get_property(np, "atmel,use-dma-rx", NULL))
- atmel_port->use_pdc_rx = true;
- else
+ if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
+ if (of_get_property(np, "dmas", NULL)) {
+ atmel_port->use_dma_rx = true;
+ atmel_port->use_pdc_rx = false;
+ } else {
+ atmel_port->use_dma_rx = false;
+ atmel_port->use_pdc_rx = true;
+ }
+ } else {
+ atmel_port->use_dma_rx = false;
atmel_port->use_pdc_rx = false;
+ }
if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
if (of_get_property(np, "dmas", NULL)) {
@@ -1726,6 +1941,7 @@ 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_rx = false;
atmel_port->use_dma_tx = false;
atmel_port->rs485 = pdata->rs485;
}