From d8d721f4c005f9a69bd1b5d5c6ba99b7e1d464de Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Tue, 25 May 2010 16:59:55 +0200 Subject: [PATCH] altera_uart: Don't take spinlock 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 (not the case on nios2 where this driver is primarily used for now, thus this bug didn't trigger). Also protect calling altera_uart_rx_chars/altera_uart_tx_chars in the interrupt handler by the port spinlock. Thanks to Ian Abbott for pointing these issues out. Cc: Ian Abbott Cc: Thomas Chou Signed-off-by: Tobias Klauser Signed-off-by: Greg Kroah-Hartman --- drivers/serial/altera_uart.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/drivers/serial/altera_uart.c b/drivers/serial/altera_uart.c index bcee156..b1609cc 100644 --- a/drivers/serial/altera_uart.c +++ b/drivers/serial/altera_uart.c @@ -89,15 +89,12 @@ static unsigned int altera_uart_tx_empty(struct uart_port *port) static unsigned int altera_uart_get_mctrl(struct uart_port *port) { struct altera_uart *pp = container_of(port, struct altera_uart, port); - unsigned long flags; unsigned int sigs; - spin_lock_irqsave(&port->lock, flags); sigs = (readl(port->membase + ALTERA_UART_STATUS_REG) & ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0; sigs |= (pp->sigs & TIOCM_RTS); - spin_unlock_irqrestore(&port->lock, flags); return sigs; } @@ -105,49 +102,37 @@ static unsigned int altera_uart_get_mctrl(struct uart_port *port) static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs) { struct altera_uart *pp = container_of(port, struct altera_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->sigs = sigs; if (sigs & TIOCM_RTS) pp->imr |= ALTERA_UART_CONTROL_RTS_MSK; else pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK; writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); } static void altera_uart_start_tx(struct uart_port *port) { struct altera_uart *pp = container_of(port, struct altera_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK; writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); } static void altera_uart_stop_tx(struct uart_port *port) { struct altera_uart *pp = container_of(port, struct altera_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK; writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); } static void altera_uart_stop_rx(struct uart_port *port) { struct altera_uart *pp = container_of(port, struct altera_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK; writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); } static void altera_uart_break_ctl(struct uart_port *port, int break_state) @@ -272,10 +257,14 @@ static irqreturn_t altera_uart_interrupt(int irq, void *data) unsigned int isr; isr = readl(port->membase + ALTERA_UART_STATUS_REG) & pp->imr; + + spin_lock(&port->lock); if (isr & ALTERA_UART_STATUS_RRDY_MSK) altera_uart_rx_chars(pp); if (isr & ALTERA_UART_STATUS_TRDY_MSK) altera_uart_tx_chars(pp); + spin_unlock(&port->lock); + return IRQ_RETVAL(isr); } -- 1.8.2.3