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tty: xuartps: Refactor IRQ handling 

The system could deadlock handling RX IRQs when RX-related IRQ
conditions became true while the receiver was disabled. To avoid this,
enable/disable the RX/TX IRQs together with the receiver/transmitter.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Soren Brinkmann 2016-01-11 17:41:37 -08:00 committed by Greg Kroah-Hartman
parent 55861d11c5
commit 373e882f9e
1 changed files with 11 additions and 6 deletions
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17
drivers/tty/serial/xilinx_uartps.c
View File

@ -126,6 +126,10 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
#define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */
#define CDNS_UART_IXR_MASK 0x00001FFF /* Valid bit mask */
#define CDNS_UART_RX_IRQS (CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | \
CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_RXTRIG | \
CDNS_UART_IXR_TOUT)
/* Goes in read_status_mask for break detection as the HW doesn't do it*/
#define CDNS_UART_IXR_BRK 0x80000000
@ -272,7 +276,8 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
*/
isrstatus = readl(port->membase + CDNS_UART_ISR_OFFSET);
cdns_uart_handle_rx(port, isrstatus);
if (isrstatus & CDNS_UART_RX_IRQS)
cdns_uart_handle_rx(port, isrstatus);
/* Dispatch an appropriate handler */
if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {
@ -580,9 +585,12 @@ static void cdns_uart_stop_rx(struct uart_port *port)
{
unsigned int regval;
/* Disable RX IRQs */
writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR_OFFSET);
/* Disable the receiver */
regval = readl(port->membase + CDNS_UART_CR_OFFSET);
regval |= CDNS_UART_CR_RX_DIS;
/* Disable the receiver */
writel(regval, port->membase + CDNS_UART_CR_OFFSET);
}
@ -820,10 +828,7 @@ static int cdns_uart_startup(struct uart_port *port)
}
/* Set the Interrupt Registers with desired interrupts */
writel(CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_PARITY |
CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN |
CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT,
port->membase + CDNS_UART_IER_OFFSET);
writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER_OFFSET);
return 0;
}