diff options
| author |   Soren Brinkmann <soren.brinkmann@xilinx.com> | 2015-12-26 02:43:50 -0800 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-06 22:52:09 -0800 |
| commit | f0f54a806b2df97485519a7c4ebc45feed08a306 (patch) | |
| tree | e3bc29f241716265548140ef3b6f6fed016b6537 /drivers/tty/serial/xilinx_uartps.c | |
| parent | tty: xuartps: Beautify read-modify writes (diff) | |
| download | linux-dev-f0f54a806b2df97485519a7c4ebc45feed08a306.tar.xz linux-dev-f0f54a806b2df97485519a7c4ebc45feed08a306.zip | |
tty: xuartps: Use spinlock to serialize HW access
Instead of disabling the IRQ, use the spin lock to serialize accesses to
the HW. This protects the driver from interference of non-IRQ callbacks
with each other and makes the driver more consistent in its
serialization method.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/xilinx_uartps.c')
| -rw-r--r-- | drivers/tty/serial/xilinx_uartps.c | 18 |
1 files changed, 6 insertions, 12 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 50d4082d2354..2c98c357d9a0 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -945,12 +945,10 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) #ifdef CONFIG_CONSOLE_POLL static int cdns_uart_poll_get_char(struct uart_port *port) { - u32 imr; int c; + unsigned long flags; - /* Disable all interrupts */ - imr = readl(port->membase + CDNS_UART_IMR_OFFSET); - writel(imr, port->membase + CDNS_UART_IDR_OFFSET); + spin_lock_irqsave(&port->lock, flags); /* Check if FIFO is empty */ if (readl(port->membase + CDNS_UART_SR_OFFSET) & CDNS_UART_SR_RXEMPTY) @@ -959,19 +957,16 @@ static int cdns_uart_poll_get_char(struct uart_port *port) c = (unsigned char) readl( port->membase + CDNS_UART_FIFO_OFFSET); - /* Enable interrupts */ - writel(imr, port->membase + CDNS_UART_IER_OFFSET); + spin_unlock_irqrestore(&port->lock, flags); return c; } static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) { - u32 imr; + unsigned long flags; - /* Disable all interrupts */ - imr = readl(port->membase + CDNS_UART_IMR_OFFSET); - writel(imr, port->membase + CDNS_UART_IDR_OFFSET); + spin_lock_irqsave(&port->lock, flags); /* Wait until FIFO is empty */ while (!(readl(port->membase + CDNS_UART_SR_OFFSET) & @@ -986,8 +981,7 @@ static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) CDNS_UART_SR_TXEMPTY)) cpu_relax(); - /* Enable interrupts */ - writel(imr, port->membase + CDNS_UART_IER_OFFSET); + spin_unlock_irqrestore(&port->lock, flags); return; } |