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Commit 0ac8382e authored by Yury Georgievskiy's avatar Yury Georgievskiy Committed by Greg Kroah-Hartman
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serial: mcf: don't take spinlocks in already protected functions 



Don't take the port spinlock in uart functions where the serial core
already takes care of locking/unlocking them.

The code would actually lock up on architectures where spinlocks are
implemented.

Also protect calling mcf_rx_chars/mcf_tx_chars in the interrupt handler by
the port spinlock and use IRQ_RETVAL to return from isr.

[akpm@linux-foundation.org: make irq-handler return value more explicit]
Signed-off-by: default avatarYury Georgievskiy <ygeorgie@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: default avatarGreg Ungerer <gerg@uclinux.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1b633184

drivers/serial/mcf.c

+13 −18
Original line number Diff line number Diff line
@@ -70,16 +70,14 @@ static unsigned int mcf_tx_empty(struct uart_port *port) 
static unsigned int mcf_get_mctrl(struct uart_port *port)

{

	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

	unsigned long flags;

	unsigned int sigs;



	spin_lock_irqsave(&port->lock, flags);

	sigs = (readb(port->membase + MCFUART_UIPR) & MCFUART_UIPR_CTS) ?

		0 : TIOCM_CTS;

	sigs |= (pp->sigs & TIOCM_RTS);

	sigs |= (mcf_getppdcd(port->line) ? TIOCM_CD : 0);

	sigs |= (mcf_getppdtr(port->line) ? TIOCM_DTR : 0);

	spin_unlock_irqrestore(&port->lock, flags);



	return sigs;

}
@@ -88,16 +86,13 @@ static unsigned int mcf_get_mctrl(struct uart_port *port) 
static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs)

{

	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

	unsigned long flags;



	spin_lock_irqsave(&port->lock, flags);

	pp->sigs = sigs;

	mcf_setppdtr(port->line, (sigs & TIOCM_DTR));

	if (sigs & TIOCM_RTS)

		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);

	else

		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP0);

	spin_unlock_irqrestore(&port->lock, flags);

}



/****************************************************************************/
@@ -105,12 +100,9 @@ static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs) 
static void mcf_start_tx(struct uart_port *port)

{

	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

	unsigned long flags;



	spin_lock_irqsave(&port->lock, flags);

	pp->imr |= MCFUART_UIR_TXREADY;

	writeb(pp->imr, port->membase + MCFUART_UIMR);

	spin_unlock_irqrestore(&port->lock, flags);

}



/****************************************************************************/
@@ -118,12 +110,9 @@ static void mcf_start_tx(struct uart_port *port) 
static void mcf_stop_tx(struct uart_port *port)

{

	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

	unsigned long flags;



	spin_lock_irqsave(&port->lock, flags);

	pp->imr &= ~MCFUART_UIR_TXREADY;

	writeb(pp->imr, port->membase + MCFUART_UIMR);

	spin_unlock_irqrestore(&port->lock, flags);

}



/****************************************************************************/
@@ -131,12 +120,9 @@ static void mcf_stop_tx(struct uart_port *port) 
static void mcf_stop_rx(struct uart_port *port)

{

	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

	unsigned long flags;



	spin_lock_irqsave(&port->lock, flags);

	pp->imr &= ~MCFUART_UIR_RXREADY;

	writeb(pp->imr, port->membase + MCFUART_UIMR);

	spin_unlock_irqrestore(&port->lock, flags);

}



/****************************************************************************/
@@ -366,13 +352,22 @@ static irqreturn_t mcf_interrupt(int irq, void *data) 
	struct uart_port *port = data;

	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

	unsigned int isr;

	irqreturn_t ret = IRQ_NONE;



	isr = readb(port->membase + MCFUART_UISR) & pp->imr;

	if (isr & MCFUART_UIR_RXREADY)



	spin_lock(&port->lock);

	if (isr & MCFUART_UIR_RXREADY) {

		mcf_rx_chars(pp);

	if (isr & MCFUART_UIR_TXREADY)

		ret = IRQ_HANDLED;

	}

	if (isr & MCFUART_UIR_TXREADY) {

		mcf_tx_chars(pp);

	return IRQ_HANDLED;

		ret = IRQ_HANDLED;

	}

	spin_unlock(&port->lock);



	return ret;

}



/****************************************************************************/