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path: root/drivers/tty/serial/8250/8250_dw.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_dw.c')
-rw-r--r--drivers/tty/serial/8250/8250_dw.c28
1 files changed, 25 insertions, 3 deletions
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index c89fafc972b6..6ee55a2d47bb 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -201,8 +201,31 @@ static unsigned int dw8250_serial_in32be(struct uart_port *p, int offset)
static int dw8250_handle_irq(struct uart_port *p)
{
+ struct uart_8250_port *up = up_to_u8250p(p);
struct dw8250_data *d = p->private_data;
unsigned int iir = p->serial_in(p, UART_IIR);
+ unsigned int status;
+ unsigned long flags;
+
+ /*
+ * There are ways to get Designware-based UARTs into a state where
+ * they are asserting UART_IIR_RX_TIMEOUT but there is no actual
+ * data available. If we see such a case then we'll do a bogus
+ * read. If we don't do this then the "RX TIMEOUT" interrupt will
+ * fire forever.
+ *
+ * This problem has only been observed so far when not in DMA mode
+ * so we limit the workaround only to non-DMA mode.
+ */
+ if (!up->dma && ((iir & 0x3f) == UART_IIR_RX_TIMEOUT)) {
+ spin_lock_irqsave(&p->lock, flags);
+ status = p->serial_in(p, UART_LSR);
+
+ if (!(status & (UART_LSR_DR | UART_LSR_BI)))
+ (void) p->serial_in(p, UART_RX);
+
+ spin_unlock_irqrestore(&p->lock, flags);
+ }
if (serial8250_handle_irq(p, iir))
return 1;
@@ -248,11 +271,11 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
if (!ret)
p->uartclk = rate;
+out:
p->status &= ~UPSTAT_AUTOCTS;
if (termios->c_cflag & CRTSCTS)
p->status |= UPSTAT_AUTOCTS;
-out:
serial8250_do_set_termios(p, termios, old);
}
@@ -326,13 +349,11 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
p->serial_in = dw8250_serial_in32;
data->uart_16550_compatible = true;
}
- p->set_termios = dw8250_set_termios;
}
/* Platforms with iDMA */
if (platform_get_resource_byname(to_platform_device(p->dev),
IORESOURCE_MEM, "lpss_priv")) {
- p->set_termios = dw8250_set_termios;
data->dma.rx_param = p->dev->parent;
data->dma.tx_param = p->dev->parent;
data->dma.fn = dw8250_idma_filter;
@@ -414,6 +435,7 @@ static int dw8250_probe(struct platform_device *pdev)
p->serial_in = dw8250_serial_in;
p->serial_out = dw8250_serial_out;
p->set_ldisc = dw8250_set_ldisc;
+ p->set_termios = dw8250_set_termios;
p->membase = devm_ioremap(dev, regs->start, resource_size(regs));
if (!p->membase)