Re: [PATCH LINUX v4 06/13] tty: xuartps: Move request_irq to after setting up the HW
From: Peter Hurley <hidden>
Date: 2015-12-10 21:41:13
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linux-arm-kernel, lkml
On 12/05/2015 08:39 PM, Soren Brinkmann wrote:
Request_irq() should be _after_ h/w programming, otherwise an interrupt could be triggered and in-progress before the h/w has been setup.
Slight misunderstanding. My fault; I should have been more explicit. 1. Any setup necessary for the isr not to be confused and misdirect spurious interrupts (or hang) should be before installing the isr with request_irq() None of this code should trigger an interrupt. 2. Clear pending interrupts 3. Install the isr with request_irq() 4. Enable interrupts For extra safety, first disable interrupts before starting h/w programming. I would do the v5 series in the same order as the v3 series only up to what I reviewed. Then do another series with the remainder plus new changes, ok? Regards, Peter Hurley
quoted hunk ↗ jump to hunk
Reported-by: Peter Hurley <redacted> Signed-off-by: Soren Brinkmann <redacted> --- v4: - this patch has been added. Thanks to Peter for pointing it out and providing commit message --- drivers/tty/serial/xilinx_uartps.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 6ffd3bbe3e18..1e9053656610 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c@@ -759,12 +759,7 @@ static void cdns_uart_set_termios(struct uart_port *port, static int cdns_uart_startup(struct uart_port *port) { unsigned long flags; - unsigned int retval = 0, status = 0; - - retval = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, - (void *)port); - if (retval) - return retval; + unsigned int status = 0; spin_lock_irqsave(&port->lock, flags);@@ -818,7 +813,7 @@ static int cdns_uart_startup(struct uart_port *port) spin_unlock_irqrestore(&port->lock, flags); - return retval; + return request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port); } /**