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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>
This commit is contained in:
Stefan Agner 2015-01-10 09:33:45 +01:00 committed by Greg Kroah-Hartman
parent 5f1437f61a
commit 4a818c4396
1 changed files with 44 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

96
drivers/tty/serial/fsl_lpuart.c
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@ -237,7 +237,8 @@ struct lpuart_port {
unsigned int rxfifo_size; unsigned int rxfifo_size;
bool lpuart32; 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_tx_chan;
struct dma_chan *dma_rx_chan; struct dma_chan *dma_rx_chan;
struct dma_async_tx_descriptor *dma_tx_desc; struct dma_async_tx_descriptor *dma_tx_desc;
@ -568,7 +569,7 @@ static void lpuart_start_tx(struct uart_port *port)
temp = readb(port->membase + UARTCR2); temp = readb(port->membase + UARTCR2);
writeb(temp | UARTCR2_TIE, 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) if (!uart_circ_empty(xmit) && !sport->dma_tx_in_progress)
lpuart_prepare_tx(sport); lpuart_prepare_tx(sport);
} else { } else {
@ -761,13 +762,13 @@ static irqreturn_t lpuart_int(int irq, void *dev_id)
crdma = readb(sport->port.membase + UARTCR5); crdma = readb(sport->port.membase + UARTCR5);
if (sts & UARTSR1_RDRF && !(crdma & UARTCR5_RDMAS)) { if (sts & UARTSR1_RDRF && !(crdma & UARTCR5_RDMAS)) {
if (sport->lpuart_dma_use) if (sport->lpuart_dma_rx_use)
lpuart_prepare_rx(sport); lpuart_prepare_rx(sport);
else else
lpuart_rxint(irq, dev_id); lpuart_rxint(irq, dev_id);
} }
if (sts & UARTSR1_TDRE && !(crdma & UARTCR5_TDMAS)) { if (sts & UARTSR1_TDRE && !(crdma & UARTCR5_TDMAS)) {
if (sport->lpuart_dma_use) if (sport->lpuart_dma_tx_use)
lpuart_pio_tx(sport); lpuart_pio_tx(sport);
else else
lpuart_txint(irq, dev_id); lpuart_txint(irq, dev_id);
@ -950,26 +951,17 @@ static int lpuart_dma_tx_request(struct uart_port *port)
{ {
struct lpuart_port *sport = container_of(port, struct lpuart_port *sport = container_of(port,
struct lpuart_port, port); struct lpuart_port, port);
struct dma_chan *tx_chan;
struct dma_slave_config dma_tx_sconfig; struct dma_slave_config dma_tx_sconfig;
dma_addr_t dma_bus; dma_addr_t dma_bus;
unsigned char *dma_buf; unsigned char *dma_buf;
int ret; int ret;
tx_chan = dma_request_slave_channel(sport->port.dev, "tx"); dma_bus = dma_map_single(sport->dma_tx_chan->device->dev,
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,
sport->port.state->xmit.buf, sport->port.state->xmit.buf,
UART_XMIT_SIZE, DMA_TO_DEVICE); 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"); dev_err(sport->port.dev, "dma_map_single tx failed\n");
dma_release_channel(tx_chan);
return -ENOMEM; return -ENOMEM;
} }
@ -978,16 +970,14 @@ static int lpuart_dma_tx_request(struct uart_port *port)
dma_tx_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; dma_tx_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_tx_sconfig.dst_maxburst = sport->txfifo_size; dma_tx_sconfig.dst_maxburst = sport->txfifo_size;
dma_tx_sconfig.direction = DMA_MEM_TO_DEV; 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) { if (ret < 0) {
dev_err(sport->port.dev, dev_err(sport->port.dev,
"Dma slave config failed, err = %d\n", ret); "Dma slave config failed, err = %d\n", ret);
dma_release_channel(tx_chan);
return ret; return ret;
} }
sport->dma_tx_chan = tx_chan;
sport->dma_tx_buf_virt = dma_buf; sport->dma_tx_buf_virt = dma_buf;
sport->dma_tx_buf_bus = dma_bus; sport->dma_tx_buf_bus = dma_bus;
sport->dma_tx_in_progress = 0; sport->dma_tx_in_progress = 0;
@ -999,34 +989,24 @@ static int lpuart_dma_rx_request(struct uart_port *port)
{ {
struct lpuart_port *sport = container_of(port, struct lpuart_port *sport = container_of(port,
struct lpuart_port, port); struct lpuart_port, port);
struct dma_chan *rx_chan;
struct dma_slave_config dma_rx_sconfig; struct dma_slave_config dma_rx_sconfig;
dma_addr_t dma_bus; dma_addr_t dma_bus;
unsigned char *dma_buf; unsigned char *dma_buf;
int ret; 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, dma_buf = devm_kzalloc(sport->port.dev,
FSL_UART_RX_DMA_BUFFER_SIZE, GFP_KERNEL); FSL_UART_RX_DMA_BUFFER_SIZE, GFP_KERNEL);
if (!dma_buf) { if (!dma_buf) {
dev_err(sport->port.dev, "Dma rx alloc failed\n"); dev_err(sport->port.dev, "Dma rx alloc failed\n");
dma_release_channel(rx_chan);
return -ENOMEM; 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); 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"); dev_err(sport->port.dev, "dma_map_single rx failed\n");
dma_release_channel(rx_chan);
return -ENOMEM; return -ENOMEM;
} }
@ -1034,16 +1014,14 @@ static int lpuart_dma_rx_request(struct uart_port *port)
dma_rx_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; dma_rx_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_rx_sconfig.src_maxburst = 1; dma_rx_sconfig.src_maxburst = 1;
dma_rx_sconfig.direction = DMA_DEV_TO_MEM; 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) { if (ret < 0) {
dev_err(sport->port.dev, dev_err(sport->port.dev,
"Dma slave config failed, err = %d\n", ret); "Dma slave config failed, err = %d\n", ret);
dma_release_channel(rx_chan);
return ret; return ret;
} }
sport->dma_rx_chan = rx_chan;
sport->dma_rx_buf_virt = dma_buf; sport->dma_rx_buf_virt = dma_buf;
sport->dma_rx_buf_bus = dma_bus; sport->dma_rx_buf_bus = dma_bus;
sport->dma_rx_in_progress = 0; sport->dma_rx_in_progress = 0;
@ -1055,31 +1033,24 @@ static void lpuart_dma_tx_free(struct uart_port *port)
{ {
struct lpuart_port *sport = container_of(port, struct lpuart_port *sport = container_of(port,
struct lpuart_port, port); struct lpuart_port, port);
struct dma_chan *dma_chan;
dma_unmap_single(sport->port.dev, sport->dma_tx_buf_bus, dma_unmap_single(sport->port.dev, sport->dma_tx_buf_bus,
UART_XMIT_SIZE, DMA_TO_DEVICE); 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_bus = 0;
sport->dma_tx_buf_virt = NULL; sport->dma_tx_buf_virt = NULL;
dma_release_channel(dma_chan);
} }
static void lpuart_dma_rx_free(struct uart_port *port) static void lpuart_dma_rx_free(struct uart_port *port)
{ {
struct lpuart_port *sport = container_of(port, struct lpuart_port *sport = container_of(port,
struct lpuart_port, port); struct lpuart_port, port);
struct dma_chan *dma_chan;
dma_unmap_single(sport->port.dev, sport->dma_rx_buf_bus, dma_unmap_single(sport->port.dev, sport->dma_rx_buf_bus,
FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE); 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_bus = 0;
sport->dma_rx_buf_virt = NULL; sport->dma_rx_buf_virt = NULL;
dma_release_channel(dma_chan);
} }
static int lpuart_startup(struct uart_port *port) static int lpuart_startup(struct uart_port *port)
@ -1098,17 +1069,21 @@ static int lpuart_startup(struct uart_port *port)
sport->rxfifo_size = 0x1 << (((temp >> UARTPFIFO_RXSIZE_OFF) & sport->rxfifo_size = 0x1 << (((temp >> UARTPFIFO_RXSIZE_OFF) &
UARTPFIFO_FIFOSIZE_MASK) + 1); UARTPFIFO_FIFOSIZE_MASK) + 1);
/* Whether use dma support by dma request results */ if (sport->dma_rx_chan && !lpuart_dma_rx_request(port)) {
if (lpuart_dma_tx_request(port) || lpuart_dma_rx_request(port)) { sport->lpuart_dma_rx_use = true;
sport->lpuart_dma_use = false;
} else {
sport->lpuart_dma_use = true;
setup_timer(&sport->lpuart_timer, lpuart_timer_func, setup_timer(&sport->lpuart_timer, lpuart_timer_func,
(unsigned long)sport); (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 = readb(port->membase + UARTCR5);
temp &= ~UARTCR5_RDMAS; temp &= ~UARTCR5_RDMAS;
writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5); 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, ret = devm_request_irq(port->dev, port->irq, lpuart_int, 0,
DRIVER_NAME, sport); DRIVER_NAME, sport);
@ -1179,12 +1154,13 @@ static void lpuart_shutdown(struct uart_port *port)
devm_free_irq(port->dev, port->irq, sport); 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); 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) static void lpuart32_shutdown(struct uart_port *port)
@ -1306,7 +1282,7 @@ lpuart_set_termios(struct uart_port *port, struct ktermios *termios,
/* update the per-port timeout */ /* update the per-port timeout */
uart_update_timeout(port, termios->c_cflag, baud); 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 */ /* Calculate delay for 1.5 DMA buffers */
sport->dma_rx_timeout = (sport->port.timeout - HZ / 50) * sport->dma_rx_timeout = (sport->port.timeout - HZ / 50) *
FSL_UART_RX_DMA_BUFFER_SIZE * 3 / FSL_UART_RX_DMA_BUFFER_SIZE * 3 /
@ -1835,6 +1811,16 @@ static int lpuart_probe(struct platform_device *pdev)
return ret; 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; return 0;
} }
@ -1846,6 +1832,12 @@ static int lpuart_remove(struct platform_device *pdev)
clk_disable_unprepare(sport->clk); 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; return 0;
} }