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Diffstat (limited to 'drivers/tty/serial/imx.c')
-rw-r--r--drivers/tty/serial/imx.c124
1 files changed, 87 insertions, 37 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index e148132506..ff32cd2d28 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -8,6 +8,7 @@
* Copyright (C) 2004 Pengutronix
*/
+#include <linux/circ_buf.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
@@ -26,6 +27,7 @@
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/dma-mapping.h>
#include <asm/irq.h>
@@ -118,6 +120,7 @@
#define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */
#define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */
#define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */
+#define UFCR_RXTL_MASK 0x3F /* Receiver trigger 6 bits wide */
#define UFCR_DCEDTE (1<<6) /* DCE/DTE mode select */
#define UFCR_RFDIV (7<<7) /* Reference freq divider mask */
#define UFCR_RFDIV_REG(x) (((x) < 7 ? 6 - (x) : 6) << 7)
@@ -521,7 +524,8 @@ static void imx_uart_dma_tx(struct imx_port *sport);
/* called with port.lock taken and irqs off */
static inline void imx_uart_transmit_buffer(struct imx_port *sport)
{
- struct circ_buf *xmit = &sport->port.state->xmit;
+ struct tty_port *tport = &sport->port.state->port;
+ unsigned char c;
if (sport->port.x_char) {
/* Send next char */
@@ -531,7 +535,8 @@ static inline void imx_uart_transmit_buffer(struct imx_port *sport)
return;
}
- if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
+ if (kfifo_is_empty(&tport->xmit_fifo) ||
+ uart_tx_stopped(&sport->port)) {
imx_uart_stop_tx(&sport->port);
return;
}
@@ -555,26 +560,22 @@ static inline void imx_uart_transmit_buffer(struct imx_port *sport)
return;
}
- while (!uart_circ_empty(xmit) &&
- !(imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL)) {
- /* send xmit->buf[xmit->tail]
- * out the port here */
- imx_uart_writel(sport, xmit->buf[xmit->tail], URTX0);
- uart_xmit_advance(&sport->port, 1);
- }
+ while (!(imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL) &&
+ uart_fifo_get(&sport->port, &c))
+ imx_uart_writel(sport, c, URTX0);
- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
uart_write_wakeup(&sport->port);
- if (uart_circ_empty(xmit))
+ if (kfifo_is_empty(&tport->xmit_fifo))
imx_uart_stop_tx(&sport->port);
}
static void imx_uart_dma_tx_callback(void *data)
{
struct imx_port *sport = data;
+ struct tty_port *tport = &sport->port.state->port;
struct scatterlist *sgl = &sport->tx_sgl[0];
- struct circ_buf *xmit = &sport->port.state->xmit;
unsigned long flags;
u32 ucr1;
@@ -592,10 +593,11 @@ static void imx_uart_dma_tx_callback(void *data)
sport->dma_is_txing = 0;
- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
uart_write_wakeup(&sport->port);
- if (!uart_circ_empty(xmit) && !uart_tx_stopped(&sport->port))
+ if (!kfifo_is_empty(&tport->xmit_fifo) &&
+ !uart_tx_stopped(&sport->port))
imx_uart_dma_tx(sport);
else if (sport->port.rs485.flags & SER_RS485_ENABLED) {
u32 ucr4 = imx_uart_readl(sport, UCR4);
@@ -609,7 +611,7 @@ static void imx_uart_dma_tx_callback(void *data)
/* called with port.lock taken and irqs off */
static void imx_uart_dma_tx(struct imx_port *sport)
{
- struct circ_buf *xmit = &sport->port.state->xmit;
+ struct tty_port *tport = &sport->port.state->port;
struct scatterlist *sgl = sport->tx_sgl;
struct dma_async_tx_descriptor *desc;
struct dma_chan *chan = sport->dma_chan_tx;
@@ -624,18 +626,10 @@ static void imx_uart_dma_tx(struct imx_port *sport)
ucr4 &= ~UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
- sport->tx_bytes = uart_circ_chars_pending(xmit);
-
- if (xmit->tail < xmit->head || xmit->head == 0) {
- sport->dma_tx_nents = 1;
- sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes);
- } else {
- sport->dma_tx_nents = 2;
- sg_init_table(sgl, 2);
- sg_set_buf(sgl, xmit->buf + xmit->tail,
- UART_XMIT_SIZE - xmit->tail);
- sg_set_buf(sgl + 1, xmit->buf, xmit->head);
- }
+ sg_init_table(sgl, ARRAY_SIZE(sport->tx_sgl));
+ sport->tx_bytes = kfifo_len(&tport->xmit_fifo);
+ sport->dma_tx_nents = kfifo_dma_out_prepare(&tport->xmit_fifo, sgl,
+ ARRAY_SIZE(sport->tx_sgl), sport->tx_bytes);
ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
if (ret == 0) {
@@ -653,8 +647,7 @@ static void imx_uart_dma_tx(struct imx_port *sport)
desc->callback = imx_uart_dma_tx_callback;
desc->callback_param = sport;
- dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
- uart_circ_chars_pending(xmit));
+ dev_dbg(dev, "TX: prepare to send %u bytes by DMA.\n", sport->tx_bytes);
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 |= UCR1_TXDMAEN;
@@ -671,9 +664,10 @@ static void imx_uart_dma_tx(struct imx_port *sport)
static void imx_uart_start_tx(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
+ struct tty_port *tport = &sport->port.state->port;
u32 ucr1;
- if (!sport->port.x_char && uart_circ_empty(&port->state->xmit))
+ if (!sport->port.x_char && kfifo_is_empty(&tport->xmit_fifo))
return;
/*
@@ -749,7 +743,7 @@ static void imx_uart_start_tx(struct uart_port *port)
return;
}
- if (!uart_circ_empty(&port->state->xmit) &&
+ if (!kfifo_is_empty(&tport->xmit_fifo) &&
!uart_tx_stopped(port))
imx_uart_dma_tx(sport);
return;
@@ -1312,7 +1306,7 @@ static void imx_uart_clear_rx_errors(struct imx_port *sport)
}
-#define TXTL_DEFAULT 2 /* reset default */
+#define TXTL_DEFAULT 8
#define RXTL_DEFAULT 8 /* 8 characters or aging timer */
#define TXTL_DMA 8 /* DMA burst setting */
#define RXTL_DMA 9 /* DMA burst setting */
@@ -1558,6 +1552,7 @@ static void imx_uart_shutdown(struct uart_port *port)
struct imx_port *sport = (struct imx_port *)port;
unsigned long flags;
u32 ucr1, ucr2, ucr4, uts;
+ int loops;
if (sport->dma_is_enabled) {
dmaengine_terminate_sync(sport->dma_chan_tx);
@@ -1620,6 +1615,56 @@ static void imx_uart_shutdown(struct uart_port *port)
ucr4 &= ~UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
+ /*
+ * We have to ensure the tx state machine ends up in OFF. This
+ * is especially important for rs485 where we must not leave
+ * the RTS signal high, blocking the bus indefinitely.
+ *
+ * All interrupts are now disabled, so imx_uart_stop_tx() will
+ * no longer be called from imx_uart_transmit_buffer(). It may
+ * still be called via the hrtimers, and if those are in play,
+ * we have to honour the delays.
+ */
+ if (sport->tx_state == WAIT_AFTER_RTS || sport->tx_state == SEND)
+ imx_uart_stop_tx(port);
+
+ /*
+ * In many cases (rs232 mode, or if tx_state was
+ * WAIT_AFTER_RTS, or if tx_state was SEND and there is no
+ * delay_rts_after_send), this will have moved directly to
+ * OFF. In rs485 mode, tx_state might already have been
+ * WAIT_AFTER_SEND and the hrtimer thus already started, or
+ * the above imx_uart_stop_tx() call could have started it. In
+ * those cases, we have to wait for the hrtimer to fire and
+ * complete the transition to OFF.
+ */
+ loops = port->rs485.flags & SER_RS485_ENABLED ?
+ port->rs485.delay_rts_after_send : 0;
+ while (sport->tx_state != OFF && loops--) {
+ uart_port_unlock_irqrestore(&sport->port, flags);
+ msleep(1);
+ uart_port_lock_irqsave(&sport->port, &flags);
+ }
+
+ if (sport->tx_state != OFF) {
+ dev_warn(sport->port.dev, "unexpected tx_state %d\n",
+ sport->tx_state);
+ /*
+ * This machine may be busted, but ensure the RTS
+ * signal is inactive in order not to block other
+ * devices.
+ */
+ if (port->rs485.flags & SER_RS485_ENABLED) {
+ ucr2 = imx_uart_readl(sport, UCR2);
+ if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
+ imx_uart_rts_active(sport, &ucr2);
+ else
+ imx_uart_rts_inactive(sport, &ucr2);
+ imx_uart_writel(sport, ucr2, UCR2);
+ }
+ sport->tx_state = OFF;
+ }
+
uart_port_unlock_irqrestore(&sport->port, flags);
clk_disable_unprepare(sport->clk_per);
@@ -1940,7 +1985,7 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio
struct serial_rs485 *rs485conf)
{
struct imx_port *sport = (struct imx_port *)port;
- u32 ucr2;
+ u32 ucr2, ufcr;
if (rs485conf->flags & SER_RS485_ENABLED) {
/* Enable receiver if low-active RTS signal is requested */
@@ -1959,8 +2004,13 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio
/* Make sure Rx is enabled in case Tx is active with Rx disabled */
if (!(rs485conf->flags & SER_RS485_ENABLED) ||
- rs485conf->flags & SER_RS485_RX_DURING_TX)
+ rs485conf->flags & SER_RS485_RX_DURING_TX) {
+ /* If the receiver trigger is 0, set it to a default value */
+ ufcr = imx_uart_readl(sport, UFCR);
+ if ((ufcr & UFCR_RXTL_MASK) == 0)
+ imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
imx_uart_start_rx(port);
+ }
return 0;
}
@@ -2010,7 +2060,7 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
struct imx_port *sport = imx_uart_ports[co->index];
struct imx_port_ucrs old_ucr;
unsigned long flags;
- unsigned int ucr1;
+ unsigned int ucr1, usr2;
int locked = 1;
if (sport->port.sysrq)
@@ -2041,8 +2091,8 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
* Finally, wait for transmitter to become empty
* and restore UCR1/2/3
*/
- while (!(imx_uart_readl(sport, USR2) & USR2_TXDC));
-
+ read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC,
+ 0, USEC_PER_SEC, false, sport, USR2);
imx_uart_ucrs_restore(sport, &old_ucr);
if (locked)
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-09 05:58:19 +0000