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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: Yury Georgievskiy <ygeorgie@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Yury Georgievskiy 2010-07-20 15:26:50 -07:00 committed by Greg Kroah-Hartman
parent 1b6331848b
commit 0ac8382e9c
1 changed files with 13 additions and 18 deletions
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31
drivers/serial/mcf.c
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@ -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;
}
/****************************************************************************/