[PATCH v6 2/3] serial: fsl_lpuart: add DMA support
Yuan Yao
yao.yuan at freescale.com
Mon Feb 17 00:28:07 EST 2014
Add dma support for lpuart. This function depend on DMA driver.
You can turn on it by write both the dmas and dma-name properties in dts node.
Signed-off-by: Yuan Yao <yao.yuan at freescale.com>
Acked-by: Arnd Bergmann <arnd at arndb.de>
---
.../devicetree/bindings/serial/fsl-lpuart.txt | 19 +-
drivers/tty/serial/fsl_lpuart.c | 430 ++++++++++++++++++++-
2 files changed, 433 insertions(+), 16 deletions(-)
diff --git a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
index 6fd1dd1..6e1cbbf 100644
--- a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
+++ b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
@@ -5,10 +5,19 @@ Reqiuired properties:
- reg : Address and length of the register set for the device
- interrupts : Should contain uart interrupt
+Optional properties:
+- dmas: A list of two dma specifiers, one for each entry in dma-names.
+- dma-names: should contain "tx" and "rx".
+
+Note: Optional properties for DMA support. Write them both or both not.
+
Example:
uart0: serial at 40027000 {
- compatible = "fsl,vf610-lpuart";
- reg = <0x40027000 0x1000>;
- interrupts = <0 61 0x00>;
- };
+ compatible = "fsl,vf610-lpuart";
+ reg = <0x40027000 0x1000>;
+ interrupts = <0 61 0x00>;
+ dmas = <&edma0 0 2>,
+ <&edma0 0 3>;
+ dma-names = "rx","tx";
+ };
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 8978dc9..c5eb897 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -13,14 +13,19 @@
#define SUPPORT_SYSRQ
#endif
-#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
#include <linux/io.h>
#include <linux/irq.h>
-#include <linux/clk.h>
+#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
-#include <linux/console.h>
+#include <linux/of_dma.h>
#include <linux/serial_core.h>
+#include <linux/slab.h>
#include <linux/tty_flip.h>
/* All registers are 8-bit width */
@@ -112,6 +117,10 @@
#define UARTSFIFO_TXOF 0x02
#define UARTSFIFO_RXUF 0x01
+#define DMA_MAXBURST 16
+#define DMA_MAXBURST_MASK (DMA_MAXBURST - 1)
+#define FSL_UART_RX_DMA_BUFFER_SIZE 64
+
#define DRIVER_NAME "fsl-lpuart"
#define DEV_NAME "ttyLP"
#define UART_NR 6
@@ -121,6 +130,24 @@ struct lpuart_port {
struct clk *clk;
unsigned int txfifo_size;
unsigned int rxfifo_size;
+
+ bool lpuart_dma_use;
+ struct dma_chan *dma_tx_chan;
+ struct dma_chan *dma_rx_chan;
+ struct dma_async_tx_descriptor *dma_tx_desc;
+ struct dma_async_tx_descriptor *dma_rx_desc;
+ dma_addr_t dma_tx_buf_bus;
+ dma_addr_t dma_rx_buf_bus;
+ dma_cookie_t dma_tx_cookie;
+ dma_cookie_t dma_rx_cookie;
+ unsigned char *dma_tx_buf_virt;
+ unsigned char *dma_rx_buf_virt;
+ unsigned int dma_tx_bytes;
+ unsigned int dma_rx_bytes;
+ int dma_tx_in_progress;
+ int dma_rx_in_progress;
+ unsigned int dma_rx_timeout;
+ struct timer_list lpuart_timer;
};
static struct of_device_id lpuart_dt_ids[] = {
@@ -131,6 +158,10 @@ static struct of_device_id lpuart_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, lpuart_dt_ids);
+/* Forward declare this for the dma callbacks*/
+static void lpuart_dma_tx_complete(void *arg);
+static void lpuart_dma_rx_complete(void *arg);
+
static void lpuart_stop_tx(struct uart_port *port)
{
unsigned char temp;
@@ -152,6 +183,210 @@ static void lpuart_enable_ms(struct uart_port *port)
{
}
+static void lpuart_copy_rx_to_tty(struct lpuart_port *sport,
+ struct tty_port *tty, int count)
+{
+ int copied;
+
+ sport->port.icount.rx += count;
+
+ if (!tty) {
+ dev_err(sport->port.dev, "No tty port\n");
+ return;
+ }
+
+ dma_sync_single_for_cpu(sport->port.dev, sport->dma_rx_buf_bus,
+ FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
+ copied = tty_insert_flip_string(tty,
+ ((unsigned char *)(sport->dma_rx_buf_virt)), count);
+
+ if (copied != count) {
+ WARN_ON(1);
+ dev_err(sport->port.dev, "RxData copy to tty layer failed\n");
+ }
+
+ dma_sync_single_for_device(sport->port.dev, sport->dma_rx_buf_bus,
+ FSL_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
+}
+
+static void lpuart_pio_tx(struct lpuart_port *sport)
+{
+ struct circ_buf *xmit = &sport->port.state->xmit;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+
+ while (!uart_circ_empty(xmit) &&
+ readb(sport->port.membase + UARTTCFIFO) < sport->txfifo_size) {
+ writeb(xmit->buf[xmit->tail], sport->port.membase + UARTDR);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ sport->port.icount.tx++;
+ }
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&sport->port);
+
+ if (uart_circ_empty(xmit))
+ writeb(readb(sport->port.membase + UARTCR5) | UARTCR5_TDMAS,
+ sport->port.membase + UARTCR5);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+}
+
+static int lpuart_dma_tx(struct lpuart_port *sport, unsigned long count)
+{
+ struct circ_buf *xmit = &sport->port.state->xmit;
+ dma_addr_t tx_bus_addr;
+
+ dma_sync_single_for_device(sport->port.dev, sport->dma_tx_buf_bus,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
+ sport->dma_tx_bytes = count & ~(DMA_MAXBURST_MASK);
+ tx_bus_addr = sport->dma_tx_buf_bus + xmit->tail;
+ sport->dma_tx_desc = dmaengine_prep_slave_single(sport->dma_tx_chan,
+ tx_bus_addr, sport->dma_tx_bytes,
+ DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
+
+ if (!sport->dma_tx_desc) {
+ dev_err(sport->port.dev, "Not able to get desc for tx\n");
+ return -EIO;
+ }
+
+ sport->dma_tx_desc->callback = lpuart_dma_tx_complete;
+ sport->dma_tx_desc->callback_param = sport;
+ sport->dma_tx_in_progress = 1;
+ sport->dma_tx_cookie = dmaengine_submit(sport->dma_tx_desc);
+ dma_async_issue_pending(sport->dma_tx_chan);
+
+ return 0;
+}
+
+static void lpuart_prepare_tx(struct lpuart_port *sport)
+{
+ struct circ_buf *xmit = &sport->port.state->xmit;
+ unsigned long count = CIRC_CNT_TO_END(xmit->head,
+ xmit->tail, UART_XMIT_SIZE);
+
+ if (!count)
+ return;
+
+ if (count < DMA_MAXBURST)
+ writeb(readb(sport->port.membase + UARTCR5) & ~UARTCR5_TDMAS,
+ sport->port.membase + UARTCR5);
+ else {
+ writeb(readb(sport->port.membase + UARTCR5) | UARTCR5_TDMAS,
+ sport->port.membase + UARTCR5);
+ lpuart_dma_tx(sport, count);
+ }
+}
+
+static void lpuart_dma_tx_complete(void *arg)
+{
+ struct lpuart_port *sport = arg;
+ struct circ_buf *xmit = &sport->port.state->xmit;
+ unsigned long flags;
+
+ async_tx_ack(sport->dma_tx_desc);
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+
+ xmit->tail = (xmit->tail + sport->dma_tx_bytes) & (UART_XMIT_SIZE - 1);
+ sport->dma_tx_in_progress = 0;
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&sport->port);
+
+ lpuart_prepare_tx(sport);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+}
+
+static int lpuart_dma_rx(struct lpuart_port *sport)
+{
+ dma_sync_single_for_device(sport->port.dev, sport->dma_rx_buf_bus,
+ FSL_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
+ sport->dma_rx_desc = dmaengine_prep_slave_single(sport->dma_rx_chan,
+ sport->dma_rx_buf_bus, FSL_UART_RX_DMA_BUFFER_SIZE,
+ DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
+
+ if (!sport->dma_rx_desc) {
+ dev_err(sport->port.dev, "Not able to get desc for rx\n");
+ return -EIO;
+ }
+
+ sport->dma_rx_desc->callback = lpuart_dma_rx_complete;
+ sport->dma_rx_desc->callback_param = sport;
+ sport->dma_rx_in_progress = 1;
+ sport->dma_rx_cookie = dmaengine_submit(sport->dma_rx_desc);
+ dma_async_issue_pending(sport->dma_rx_chan);
+
+ return 0;
+}
+
+static void lpuart_dma_rx_complete(void *arg)
+{
+ struct lpuart_port *sport = arg;
+ struct tty_port *port = &sport->port.state->port;
+ unsigned long flags;
+
+ async_tx_ack(sport->dma_rx_desc);
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+
+ sport->dma_rx_in_progress = 0;
+ lpuart_copy_rx_to_tty(sport, port, FSL_UART_RX_DMA_BUFFER_SIZE);
+ tty_flip_buffer_push(port);
+ lpuart_dma_rx(sport);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+}
+
+static void lpuart_timer_func(unsigned long data)
+{
+ struct lpuart_port *sport = (struct lpuart_port *)data;
+ struct tty_port *port = &sport->port.state->port;
+ struct dma_tx_state state;
+ unsigned long flags;
+ unsigned char temp;
+ int count;
+
+ del_timer(&sport->lpuart_timer);
+ dmaengine_pause(sport->dma_rx_chan);
+ dmaengine_tx_status(sport->dma_rx_chan, sport->dma_rx_cookie, &state);
+ dmaengine_terminate_all(sport->dma_rx_chan);
+ count = FSL_UART_RX_DMA_BUFFER_SIZE - state.residue;
+ async_tx_ack(sport->dma_rx_desc);
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+
+ sport->dma_rx_in_progress = 0;
+ lpuart_copy_rx_to_tty(sport, port, count);
+ tty_flip_buffer_push(port);
+ temp = readb(sport->port.membase + UARTCR5);
+ writeb(temp & ~UARTCR5_RDMAS, sport->port.membase + UARTCR5);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+}
+
+static inline void lpuart_prepare_rx(struct lpuart_port *sport)
+{
+ unsigned long flags;
+ unsigned char temp;
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+
+ init_timer(&sport->lpuart_timer);
+ sport->lpuart_timer.function = lpuart_timer_func;
+ sport->lpuart_timer.data = (unsigned long)sport;
+ sport->lpuart_timer.expires = jiffies + sport->dma_rx_timeout;
+ add_timer(&sport->lpuart_timer);
+
+ lpuart_dma_rx(sport);
+ temp = readb(sport->port.membase + UARTCR5);
+ writeb(temp | UARTCR5_RDMAS, sport->port.membase + UARTCR5);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+}
+
static inline void lpuart_transmit_buffer(struct lpuart_port *sport)
{
struct circ_buf *xmit = &sport->port.state->xmit;
@@ -172,14 +407,21 @@ static inline void lpuart_transmit_buffer(struct lpuart_port *sport)
static void lpuart_start_tx(struct uart_port *port)
{
- struct lpuart_port *sport = container_of(port, struct lpuart_port, port);
+ struct lpuart_port *sport = container_of(port,
+ struct lpuart_port, port);
+ struct circ_buf *xmit = &sport->port.state->xmit;
unsigned char temp;
temp = readb(port->membase + UARTCR2);
writeb(temp | UARTCR2_TIE, port->membase + UARTCR2);
- if (readb(port->membase + UARTSR1) & UARTSR1_TDRE)
- lpuart_transmit_buffer(sport);
+ if (sport->lpuart_dma_use) {
+ if (!uart_circ_empty(xmit) && !sport->dma_tx_in_progress)
+ lpuart_prepare_tx(sport);
+ } else {
+ if (readb(port->membase + UARTSR1) & UARTSR1_TDRE)
+ lpuart_transmit_buffer(sport);
+ }
}
static irqreturn_t lpuart_txint(int irq, void *dev_id)
@@ -279,12 +521,19 @@ static irqreturn_t lpuart_int(int irq, void *dev_id)
sts = readb(sport->port.membase + UARTSR1);
- if (sts & UARTSR1_RDRF)
- lpuart_rxint(irq, dev_id);
-
+ if (sts & UARTSR1_RDRF) {
+ if (sport->lpuart_dma_use)
+ lpuart_prepare_rx(sport);
+ else
+ lpuart_rxint(irq, dev_id);
+ }
if (sts & UARTSR1_TDRE &&
- !(readb(sport->port.membase + UARTCR5) & UARTCR5_TDMAS))
- lpuart_txint(irq, dev_id);
+ !(readb(sport->port.membase + UARTCR5) & UARTCR5_TDMAS)) {
+ if (sport->lpuart_dma_use)
+ lpuart_pio_tx(sport);
+ else
+ lpuart_txint(irq, dev_id);
+ }
return IRQ_HANDLED;
}
@@ -366,13 +615,156 @@ static void lpuart_setup_watermark(struct lpuart_port *sport)
writeb(UARTCFIFO_TXFLUSH | UARTCFIFO_RXFLUSH,
sport->port.membase + UARTCFIFO);
- writeb(2, sport->port.membase + UARTTWFIFO);
+ writeb(0, sport->port.membase + UARTTWFIFO);
writeb(1, sport->port.membase + UARTRWFIFO);
/* Restore cr2 */
writeb(cr2_saved, sport->port.membase + UARTCR2);
}
+static int lpuart_dma_tx_request(struct uart_port *port)
+{
+ 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,
+ sport->port.state->xmit.buf,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
+
+ if (dma_mapping_error(tx_chan->device->dev, dma_bus)) {
+ dev_err(sport->port.dev, "dma_map_single tx failed\n");
+ dma_release_channel(tx_chan);
+ return -ENOMEM;
+ }
+
+ dma_buf = sport->port.state->xmit.buf;
+ dma_tx_sconfig.dst_addr = sport->port.mapbase + UARTDR;
+ dma_tx_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ dma_tx_sconfig.dst_maxburst = DMA_MAXBURST;
+ dma_tx_sconfig.direction = DMA_MEM_TO_DEV;
+ ret = dmaengine_slave_config(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;
+
+ return 0;
+}
+
+static int lpuart_dma_rx_request(struct uart_port *port)
+{
+ 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,
+ FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
+
+ if (dma_mapping_error(rx_chan->device->dev, dma_bus)) {
+ dev_err(sport->port.dev, "dma_map_single rx failed\n");
+ dma_release_channel(rx_chan);
+ return -ENOMEM;
+ }
+
+ dma_rx_sconfig.src_addr = sport->port.mapbase + UARTDR;
+ 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);
+
+ 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;
+
+ sport->dma_rx_timeout = (sport->port.timeout - HZ / 50) *
+ FSL_UART_RX_DMA_BUFFER_SIZE * 3 /
+ sport->rxfifo_size / 2;
+
+ if (sport->dma_rx_timeout < msecs_to_jiffies(20))
+ sport->dma_rx_timeout = msecs_to_jiffies(20);
+
+ return 0;
+}
+
+static void lpuart_dma_tx_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_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)
{
struct lpuart_port *sport = container_of(port, struct lpuart_port, port);
@@ -380,6 +772,15 @@ static int lpuart_startup(struct uart_port *port)
unsigned long flags;
unsigned char temp;
+ /*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;
+ temp = readb(port->membase + UARTCR5);
+ writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5);
+ }
+
ret = devm_request_irq(port->dev, port->irq, lpuart_int, 0,
DRIVER_NAME, sport);
if (ret)
@@ -414,6 +815,11 @@ static void lpuart_shutdown(struct uart_port *port)
spin_unlock_irqrestore(&port->lock, flags);
devm_free_irq(port->dev, port->irq, sport);
+
+ if (sport->lpuart_dma_use) {
+ lpuart_dma_tx_free(port);
+ lpuart_dma_rx_free(port);
+ }
}
static void
--
1.8.4
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