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Message-Id: <1413450267-24760-1-git-send-email-ricardo.ribalda@gmail.com>
Date: Thu, 16 Oct 2014 11:04:27 +0200
From: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
To: linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>,
Nicolas Ferre <nicolas.ferre@...el.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jslaby@...e.cz>,
One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
Subject: [PATCH] tty/serial_core: Introduce lock mechanism for RS485
Introduce an homogeneous lock system between setting and using the rs485
data of the uart_port.
This patch should not be split into multiple ones in order to avoid
leaving the tree in an unstable state.
Suggested-by: Alan Cox <alan@...ux.intel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
Cc: Nicolas Ferre <nicolas.ferre@...el.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Jiri Slaby <jslaby@...e.cz>
Cc: One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
---
This patch sits on top of the series: "[PATCH 00/12] Handle
TIOC[GS]RS485 iocts on serial_core"
If there are major changes on the other patches I will resend the whole
patchset with this patch as part of it
v2: Implement changes suggested by Alan:
-The copy needs to go to a temporary before the lock is taken
otherwise we may sleep on a pagefault with irqs off
drivers/tty/serial/atmel_serial.c | 10 ++++------
drivers/tty/serial/mcf.c | 5 +----
drivers/tty/serial/omap-serial.c | 3 ---
drivers/tty/serial/serial_core.c | 13 ++++++++++++-
4 files changed, 17 insertions(+), 14 deletions(-)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index e8df8e4..32b2a8d 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -293,9 +293,6 @@ static int atmel_config_rs485(struct uart_port *port,
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int mode;
- unsigned long flags;
-
- spin_lock_irqsave(&port->lock, flags);
/* Disable interrupts */
UART_PUT_IDR(port, atmel_port->tx_done_mask);
@@ -326,8 +323,6 @@ static int atmel_config_rs485(struct uart_port *port,
/* Enable interrupts */
UART_PUT_IER(port, atmel_port->tx_done_mask);
- spin_unlock_irqrestore(&port->lock, flags);
-
return 0;
}
@@ -2509,6 +2504,7 @@ static int atmel_serial_probe(struct platform_device *pdev)
struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev);
void *data;
int ret = -ENODEV;
+ bool rs485_enabled;
BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));
@@ -2556,6 +2552,8 @@ static int atmel_serial_probe(struct platform_device *pdev)
port->rx_ring.buf = data;
}
+ rs485_enabled = port->uart.rs485.flags & SER_RS485_ENABLED;
+
ret = uart_add_one_port(&atmel_uart, &port->uart);
if (ret)
goto err_add_port;
@@ -2574,7 +2572,7 @@ static int atmel_serial_probe(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 1);
platform_set_drvdata(pdev, port);
- if (port->uart.rs485.flags & SER_RS485_ENABLED) {
+ if (rs485_enabled) {
UART_PUT_MR(&port->uart, ATMEL_US_USMODE_NORMAL);
UART_PUT_CR(&port->uart, ATMEL_US_RTSEN);
}
diff --git a/drivers/tty/serial/mcf.c b/drivers/tty/serial/mcf.c
index d7be1f1..fdd5c7b 100644
--- a/drivers/tty/serial/mcf.c
+++ b/drivers/tty/serial/mcf.c
@@ -257,12 +257,12 @@ static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
mr2 |= MCFUART_MR2_TXCTS;
}
+ spin_lock_irqsave(&port->lock, flags);
if (port->rs485.flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
mr2 |= MCFUART_MR2_TXRTS;
}
- spin_lock_irqsave(&port->lock, flags);
uart_update_timeout(port, termios->c_cflag, baud);
writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
@@ -442,10 +442,8 @@ static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)
static int mcf_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
{
struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
- unsigned long flags;
unsigned char mr1, mr2;
- spin_lock_irqsave(&port->lock, flags);
/* Get mode registers */
mr1 = readb(port->membase + MCFUART_UMR);
mr2 = readb(port->membase + MCFUART_UMR);
@@ -460,7 +458,6 @@ static int mcf_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
writeb(mr1, port->membase + MCFUART_UMR);
writeb(mr2, port->membase + MCFUART_UMR);
port->rs485 = *rs485;
- spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 9d4726f..6675dbf 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1360,12 +1360,10 @@ static int
serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
{
struct uart_omap_port *up = to_uart_omap_port(port);
- unsigned long flags;
unsigned int mode;
int val;
pm_runtime_get_sync(up->dev);
- spin_lock_irqsave(&up->port.lock, flags);
/* Disable interrupts from this port */
mode = up->ier;
@@ -1401,7 +1399,6 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
serial_out(up, UART_OMAP_SCR, up->scr);
}
- spin_unlock_irqrestore(&up->port.lock, flags);
pm_runtime_mark_last_busy(up->dev);
pm_runtime_put_autosuspend(up->dev);
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index b59c925..4d0f1f1 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1154,8 +1154,16 @@ static int uart_get_icount(struct tty_struct *tty,
static int uart_get_rs485_config(struct uart_port *port,
struct serial_rs485 __user *rs485)
{
- if (copy_to_user(rs485, &port->rs485, sizeof(port->rs485)))
+ unsigned long flags;
+ struct serial_rs485 aux;
+
+ spin_lock_irqsave(&port->lock, flags);
+ aux = port->rs485;
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ if (copy_to_user(rs485, &aux, sizeof(aux)))
return -EFAULT;
+
return 0;
}
@@ -1164,6 +1172,7 @@ static int uart_set_rs485_config(struct uart_port *port,
{
struct serial_rs485 rs485;
int ret;
+ unsigned long flags;
if (!port->rs485_config)
return -ENOIOCTLCMD;
@@ -1171,7 +1180,9 @@ static int uart_set_rs485_config(struct uart_port *port,
if (copy_from_user(&rs485, rs485_user, sizeof(rs485_user)))
return -EFAULT;
+ spin_lock_irqsave(&port->lock, flags);
ret = port->rs485_config(port, &rs485);
+ spin_unlock_irqrestore(&port->lock, flags);
if (ret)
return ret;
--
2.1.1
--
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