The patch adds missing spin-locks and allows to change termios
settings during tx.
The patch also fixes direct call its enable_ms() according to
commit d41510ce2f07
("serial: Take uart port lock for direct *_enable_ms()")
The patch applies to next. Please test it with DMA enabled.
Most lock places come from commit 332ec0558ca of the repo
https://github.com/dgii/yocto-linux
According to atmel_serial's code and other drivers code
tty_flip_buffer_push() shouldn't be in lock - so I fixed it.
However I'm not convinced they are right so RFC sent.
The lock is not always used when auart's registers touched -
is it ok?
Signed-off-by: Janusz Uzycki <j.uzycki@xxxxxxxxxxxxxx>
---
drivers/tty/serial/mxs-auart.c | 35 +++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 518eac6..7667c95 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -210,7 +210,9 @@ static void dma_tx_callback(void *param)
{
struct mxs_auart_port *s = param;
struct circ_buf *xmit = &s->port.state->xmit;
+ unsigned long flags;
+ spin_lock_irqsave(&s->port.lock, flags);
dma_unmap_sg(s->dev, &s->tx_sgl, 1, DMA_TO_DEVICE);
/* clear the bit used to serialize the DMA tx. */
@@ -220,6 +222,7 @@ static void dma_tx_callback(void *param)
/* wake up the possible processes. */
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&s->port);
+ spin_unlock_irqrestore(&s->port.lock, flags);
mxs_auart_tx_chars(s);
}
@@ -261,6 +264,7 @@ static int mxs_auart_dma_tx(struct mxs_auart_port *s, int size)
static void mxs_auart_tx_chars(struct mxs_auart_port *s)
{
struct circ_buf *xmit = &s->port.state->xmit;
+ unsigned long flags;
if (auart_dma_enabled(s)) {
u32 i = 0;
@@ -313,8 +317,11 @@ static void mxs_auart_tx_chars(struct mxs_auart_port *s)
} else
break;
}
- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) {
+ spin_lock_irqsave(&s->port.lock, flags);
uart_write_wakeup(&s->port);
+ spin_unlock_irqrestore(&s->port.lock, flags);
+ }
if (uart_circ_empty(&(s->port.state->xmit)))
writel(AUART_INTR_TXIEN,
@@ -375,6 +382,7 @@ out:
static void mxs_auart_rx_chars(struct mxs_auart_port *s)
{
u32 stat = 0;
+ unsigned long flags;
for (;;) {
stat = readl(s->port.membase + AUART_STAT);
@@ -383,7 +391,9 @@ static void mxs_auart_rx_chars(struct mxs_auart_port *s)
mxs_auart_rx_char(s);
}
+ spin_lock_irqsave(&s->port.lock, flags);
writel(stat, s->port.membase + AUART_STAT);
+ spin_unlock_irqrestore(&s->port.lock, flags);
tty_flip_buffer_push(&s->port.state->port);
}
@@ -534,7 +544,9 @@ static void dma_rx_callback(void *arg)
struct tty_port *port = &s->port.state->port;
int count;
u32 stat;
+ unsigned long flags;
+ spin_lock_irqsave(&s->port.lock, flags);
dma_unmap_sg(s->dev, &s->rx_sgl, 1, DMA_FROM_DEVICE);
stat = readl(s->port.membase + AUART_STAT);
@@ -545,6 +557,7 @@ static void dma_rx_callback(void *arg)
tty_insert_flip_string(port, s->rx_dma_buf, count);
writel(stat, s->port.membase + AUART_STAT);
+ spin_unlock_irqrestore(&s->port.lock, flags);
tty_flip_buffer_push(port);
/* start the next DMA for RX. */
@@ -606,7 +619,9 @@ static void mxs_auart_dma_exit_channel(struct mxs_auart_port *s)
static void mxs_auart_dma_exit(struct mxs_auart_port *s)
{
+ unsigned long flags;
+ spin_lock_irqsave(&s->port.lock, flags);
writel(AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE | AUART_CTRL2_DMAONERR,
s->port.membase + AUART_CTRL2_CLR);
@@ -614,13 +629,17 @@ static void mxs_auart_dma_exit(struct mxs_auart_port *s)
s->flags &= ~MXS_AUART_DMA_ENABLED;
clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
clear_bit(MXS_AUART_DMA_RX_READY, &s->flags);
+ spin_unlock_irqrestore(&s->port.lock, flags);
}
static int mxs_auart_dma_init(struct mxs_auart_port *s)
{
+ unsigned long flags;
+
if (auart_dma_enabled(s))
return 0;
+ spin_lock_irqsave(&s->port.lock, flags);
/* init for RX */
s->rx_dma_chan = dma_request_slave_channel(s->dev, "rx");
if (!s->rx_dma_chan)
@@ -644,9 +663,12 @@ static int mxs_auart_dma_init(struct mxs_auart_port *s)
/* The DMA buffer is now the FIFO the TTY subsystem can use */
s->port.fifosize = UART_XMIT_SIZE;
+ spin_unlock_irqrestore(&s->port.lock, flags);
+
return 0;
err_out:
+ spin_unlock_irqrestore(&s->port.lock, flags);
mxs_auart_dma_exit_channel(s);
return -EINVAL;
@@ -663,6 +685,7 @@ static void mxs_auart_settermios(struct uart_port *u,
struct mxs_auart_port *s = to_auart_port(u);
u32 bm, ctrl, ctrl2, div;
unsigned int cflag, baud;
+ unsigned long flags;
cflag = termios->c_cflag;
@@ -760,11 +783,15 @@ static void mxs_auart_settermios(struct uart_port *u,
ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F);
ctrl |= AUART_LINECTRL_BAUD_DIVINT(div >> 6);
+ spin_lock_irqsave(&s->port.lock, flags);
+
writel(ctrl, u->membase + AUART_LINECTRL);
writel(ctrl2, u->membase + AUART_CTRL2);
uart_update_timeout(u, termios->c_cflag, baud);
+ spin_unlock_irqrestore(&s->port.lock, flags);
+
/* prepare for the DMA RX. */
if (auart_dma_enabled(s) &&
!test_and_set_bit(MXS_AUART_DMA_RX_READY, &s->flags)) {
@@ -778,18 +805,24 @@ static void mxs_auart_settermios(struct uart_port *u,
}
}
+ spin_lock_irqsave(&s->port.lock, flags);
+
/* CTS flow-control and modem-status interrupts */
if (UART_ENABLE_MS(u, termios->c_cflag))
mxs_auart_enable_ms(u);
else
mxs_auart_disable_ms(u);
+
+ spin_unlock_irqrestore(&s->port.lock, flags);
}
static void mxs_auart_set_ldisc(struct uart_port *port, int new)
{
if (new == N_PPS) {
port->flags |= UPF_HARDPPS_CD;
+ spin_lock_irq(&port->lock);
mxs_auart_enable_ms(port);
+ spin_unlock_irq(&port->lock);
} else {
port->flags &= ~UPF_HARDPPS_CD;
}
--
1.7.11.3
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