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Date: Sun, 12 Oct 2014 07:23:33 +0200
From: Nicolas Ferre <nicolas.ferre@...el.com>
To: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>,
<linux-kernel@...r.kernel.org>, <linux-serial@...r.kernel.org>
CC: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jslaby@...e.cz>,
One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
Subject: Re: [PATCH] tty/serial_core: Introduce lock mechanism for RS485
On 10/10/2014 15:38, Ricardo Ribalda Delgado :
> 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>
> 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
>
> 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;
> +
I have the feeling that moving the code chunk that uses this new
variable (rs485_enabled) here ...
> 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);
> }
... (this one ^^^) up where you can test the SER_RS485_ENABLED, can be
even simpler.
otherwise, it seems good so you can add my:
Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
Thanks.
> 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..b574dcd 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;
> + int ret;
> +
> + spin_lock_irqsave(&port->lock, flags);
> + ret = copy_to_user(rs485, &port->rs485, sizeof(port->rs485));
> + spin_unlock_irqrestore(&port->lock, flags);
> +
> + if (ret)
> 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;
>
>
--
Nicolas Ferre
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