serial: fsl_lpuart: move DMA channel request to probe
Move the DMA channel request to probe to avoid requesting the DMA
channel on each opening of the ttyLPx device. This also fixes a
potential issue that TX channel is not freed when only RX channel
allocation fails. The DMA channels are now handled independently,
so one could use UART with DMA only in TX direction for instance.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index e95c497..0ea0af7 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -237,7 +237,8 @@
unsigned int rxfifo_size;
bool lpuart32;
- bool lpuart_dma_use;
+ bool lpuart_dma_tx_use;
+ bool lpuart_dma_rx_use;
struct dma_chan *dma_tx_chan;
struct dma_chan *dma_rx_chan;
struct dma_async_tx_descriptor *dma_tx_desc;
@@ -568,7 +569,7 @@
temp = readb(port->membase + UARTCR2);
writeb(temp | UARTCR2_TIE, port->membase + UARTCR2);
- if (sport->lpuart_dma_use) {
+ if (sport->lpuart_dma_tx_use) {
if (!uart_circ_empty(xmit) && !sport->dma_tx_in_progress)
lpuart_prepare_tx(sport);
} else {
@@ -761,13 +762,13 @@
crdma = readb(sport->port.membase + UARTCR5);
if (sts & UARTSR1_RDRF && !(crdma & UARTCR5_RDMAS)) {
- if (sport->lpuart_dma_use)
+ if (sport->lpuart_dma_rx_use)
lpuart_prepare_rx(sport);
else
lpuart_rxint(irq, dev_id);
}
if (sts & UARTSR1_TDRE && !(crdma & UARTCR5_TDMAS)) {
- if (sport->lpuart_dma_use)
+ if (sport->lpuart_dma_tx_use)
lpuart_pio_tx(sport);
else
lpuart_txint(irq, dev_id);
@@ -950,26 +951,17 @@
{
struct lpuart_port *sport = container_of(port,
struct lpuart_port, port);
- struct dma_chan *tx_chan;
struct dma_slave_config dma_tx_sconfig;
dma_addr_t dma_bus;
unsigned char *dma_buf;
int ret;
- tx_chan = dma_request_slave_channel(sport->port.dev, "tx");
-
- if (!tx_chan) {
- dev_err(sport->port.dev, "Dma tx channel request failed!\n");
- return -ENODEV;
- }
-
- dma_bus = dma_map_single(tx_chan->device->dev,
+ dma_bus = dma_map_single(sport->dma_tx_chan->device->dev,
sport->port.state->xmit.buf,
UART_XMIT_SIZE, DMA_TO_DEVICE);
- if (dma_mapping_error(tx_chan->device->dev, dma_bus)) {
+ if (dma_mapping_error(sport->dma_tx_chan->device->dev, dma_bus)) {
dev_err(sport->port.dev, "dma_map_single tx failed\n");
- dma_release_channel(tx_chan);
return -ENOMEM;
}
@@ -978,16 +970,14 @@
dma_tx_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_tx_sconfig.dst_maxburst = sport->txfifo_size;
dma_tx_sconfig.direction = DMA_MEM_TO_DEV;
- ret = dmaengine_slave_config(tx_chan, &dma_tx_sconfig);
+ ret = dmaengine_slave_config(sport->dma_tx_chan, &dma_tx_sconfig);
if (ret < 0) {
dev_err(sport->port.dev,
"Dma slave config failed, err = %d\n", ret);
- dma_release_channel(tx_chan);
return ret;
}
- sport->dma_tx_chan = tx_chan;
sport->dma_tx_buf_virt = dma_buf;
sport->dma_tx_buf_bus = dma_bus;
sport->dma_tx_in_progress = 0;
@@ -999,34 +989,24 @@
{
struct lpuart_port *sport = container_of(port,
struct lpuart_port, port);
- struct dma_chan *rx_chan;
struct dma_slave_config dma_rx_sconfig;
dma_addr_t dma_bus;
unsigned char *dma_buf;
int ret;
- rx_chan = dma_request_slave_channel(sport->port.dev, "rx");
-
- if (!rx_chan) {
- dev_err(sport->port.dev, "Dma rx channel request failed!\n");
- return -ENODEV;
- }
-
dma_buf = devm_kzalloc(sport->port.dev,
FSL_UART_RX_DMA_BUFFER_SIZE, GFP_KERNEL);
if (!dma_buf) {
dev_err(sport->port.dev, "Dma rx alloc failed\n");
- dma_release_channel(rx_chan);
return -ENOMEM;
}
- dma_bus = dma_map_single(rx_chan->device->dev, dma_buf,
+ dma_bus = dma_map_single(sport->dma_rx_chan->device->dev, dma_buf,
FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
- if (dma_mapping_error(rx_chan->device->dev, dma_bus)) {
+ if (dma_mapping_error(sport->dma_rx_chan->device->dev, dma_bus)) {
dev_err(sport->port.dev, "dma_map_single rx failed\n");
- dma_release_channel(rx_chan);
return -ENOMEM;
}
@@ -1034,16 +1014,14 @@
dma_rx_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_rx_sconfig.src_maxburst = 1;
dma_rx_sconfig.direction = DMA_DEV_TO_MEM;
- ret = dmaengine_slave_config(rx_chan, &dma_rx_sconfig);
+ ret = dmaengine_slave_config(sport->dma_rx_chan, &dma_rx_sconfig);
if (ret < 0) {
dev_err(sport->port.dev,
"Dma slave config failed, err = %d\n", ret);
- dma_release_channel(rx_chan);
return ret;
}
- sport->dma_rx_chan = rx_chan;
sport->dma_rx_buf_virt = dma_buf;
sport->dma_rx_buf_bus = dma_bus;
sport->dma_rx_in_progress = 0;
@@ -1055,31 +1033,24 @@
{
struct lpuart_port *sport = container_of(port,
struct lpuart_port, port);
- struct dma_chan *dma_chan;
dma_unmap_single(sport->port.dev, sport->dma_tx_buf_bus,
UART_XMIT_SIZE, DMA_TO_DEVICE);
- dma_chan = sport->dma_tx_chan;
- sport->dma_tx_chan = NULL;
+
sport->dma_tx_buf_bus = 0;
sport->dma_tx_buf_virt = NULL;
- dma_release_channel(dma_chan);
}
static void lpuart_dma_rx_free(struct uart_port *port)
{
struct lpuart_port *sport = container_of(port,
struct lpuart_port, port);
- struct dma_chan *dma_chan;
dma_unmap_single(sport->port.dev, sport->dma_rx_buf_bus,
FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
- dma_chan = sport->dma_rx_chan;
- sport->dma_rx_chan = NULL;
sport->dma_rx_buf_bus = 0;
sport->dma_rx_buf_virt = NULL;
- dma_release_channel(dma_chan);
}
static int lpuart_startup(struct uart_port *port)
@@ -1098,17 +1069,21 @@
sport->rxfifo_size = 0x1 << (((temp >> UARTPFIFO_RXSIZE_OFF) &
UARTPFIFO_FIFOSIZE_MASK) + 1);
- /* Whether use dma support by dma request results */
- if (lpuart_dma_tx_request(port) || lpuart_dma_rx_request(port)) {
- sport->lpuart_dma_use = false;
- } else {
- sport->lpuart_dma_use = true;
+ if (sport->dma_rx_chan && !lpuart_dma_rx_request(port)) {
+ sport->lpuart_dma_rx_use = true;
setup_timer(&sport->lpuart_timer, lpuart_timer_func,
(unsigned long)sport);
+ } else
+ sport->lpuart_dma_rx_use = false;
+
+
+ if (sport->dma_tx_chan && !lpuart_dma_tx_request(port)) {
+ sport->lpuart_dma_tx_use = true;
temp = readb(port->membase + UARTCR5);
temp &= ~UARTCR5_RDMAS;
writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5);
- }
+ } else
+ sport->lpuart_dma_tx_use = false;
ret = devm_request_irq(port->dev, port->irq, lpuart_int, 0,
DRIVER_NAME, sport);
@@ -1179,12 +1154,13 @@
devm_free_irq(port->dev, port->irq, sport);
- if (sport->lpuart_dma_use) {
+ if (sport->lpuart_dma_rx_use) {
+ lpuart_dma_rx_free(&sport->port);
del_timer_sync(&sport->lpuart_timer);
-
- lpuart_dma_tx_free(port);
- lpuart_dma_rx_free(port);
}
+
+ if (sport->lpuart_dma_tx_use)
+ lpuart_dma_tx_free(&sport->port);
}
static void lpuart32_shutdown(struct uart_port *port)
@@ -1306,7 +1282,7 @@
/* update the per-port timeout */
uart_update_timeout(port, termios->c_cflag, baud);
- if (sport->lpuart_dma_use) {
+ if (sport->lpuart_dma_rx_use) {
/* Calculate delay for 1.5 DMA buffers */
sport->dma_rx_timeout = (sport->port.timeout - HZ / 50) *
FSL_UART_RX_DMA_BUFFER_SIZE * 3 /
@@ -1835,6 +1811,16 @@
return ret;
}
+ sport->dma_tx_chan = dma_request_slave_channel(sport->port.dev, "tx");
+ if (!sport->dma_tx_chan)
+ dev_info(sport->port.dev, "DMA tx channel request failed, "
+ "operating without tx DMA\n");
+
+ sport->dma_rx_chan = dma_request_slave_channel(sport->port.dev, "rx");
+ if (!sport->dma_rx_chan)
+ dev_info(sport->port.dev, "DMA rx channel request failed, "
+ "operating without rx DMA\n");
+
return 0;
}
@@ -1846,6 +1832,12 @@
clk_disable_unprepare(sport->clk);
+ if (sport->dma_tx_chan)
+ dma_release_channel(sport->dma_tx_chan);
+
+ if (sport->dma_rx_chan)
+ dma_release_channel(sport->dma_rx_chan);
+
return 0;
}