[PATCH 3/4] serial: 8250: omap: Fix life cycle issues for interrupt handlers

Tony Lindgren
2023-05-08T08:20:56Z

We have the struct uart_8250_port instance recycled on device rebind while
the struct omap8250_priv instance is not. For the console uart,
__tty_hangup() does not call tty->ops->hangup() as cons_filp stays open,
and uart shutdown won't get called. This means we have a stale
priv->wakeirq handler around after unbind, and port->irq is not freed on
unbind.

There's no need to claim the interrupts on startup. We can fix this and
simplify the driver a bit by claiming the interrupts in probe, and clearing
them on remove. For the device interrupt, we can use devm_request_irq().

To do this, we change omap8250_irq() to use struct omap8250_priv data
directly so we don't have to wait for the assigned port from
serial8250_register_8250_port().

We must also drop IRQF_SHARED to set IRQ_NOAUTOEN to avoid spurious
interrupts until the port has been registered. There's no need for
IRQF_SHARED for 8250_omap, the serial port interrupt lines are dedicated
lines.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
drivers/tty/serial/8250/8250_omap.c | 33 ++++++++++++++---------------
1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -623,9 +623,9 @@ static int omap_8250_dma_handle_irq(struct uart_port *port);

static irqreturn_t omap8250_irq(int irq, void *dev_id)
{
- struct uart_port *port = dev_id;
- struct omap8250_priv *priv = port->private_data;
- struct uart_8250_port *up = up_to_u8250p(port);
+ struct omap8250_priv *priv = dev_id;
+ struct uart_8250_port *up = serial8250_get_port(priv->line);
+ struct uart_port *port = &up->port;
unsigned int iir, lsr;
int ret;

@@ -709,11 +709,6 @@ static int omap_8250_startup(struct uart_port *port)
}
}

- ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED,
- dev_name(port->dev), port);
- if (ret < 0)
- goto err;
-
up->ier = UART_IER_RLSI | UART_IER_RDI;
serial_out(up, UART_IER, up->ier);

@@ -730,14 +725,11 @@ static int omap_8250_startup(struct uart_port *port)
if (up->dma && !(priv->habit & UART_HAS_EFR2))
up->dma->rx_dma(up);

+ enable_irq(up->port.irq);
+
pm_runtime_mark_last_busy(port->dev);
pm_runtime_put_autosuspend(port->dev);
return 0;
-err:
- pm_runtime_mark_last_busy(port->dev);
- pm_runtime_put_autosuspend(port->dev);
- dev_pm_clear_wake_irq(port->dev);
- return ret;
}

static void omap_8250_shutdown(struct uart_port *port)
@@ -757,6 +749,8 @@ static void omap_8250_shutdown(struct uart_port *port)

up->ier = 0;
serial_out(up, UART_IER, 0);
+ disable_irq_nosync(up->port.irq);
+ dev_pm_clear_wake_irq(port->dev);

if (up->dma)
serial8250_release_dma(up);
@@ -770,8 +764,6 @@ static void omap_8250_shutdown(struct uart_port *port)

pm_runtime_mark_last_busy(port->dev);
pm_runtime_put_autosuspend(port->dev);
- free_irq(port->irq, port);
- dev_pm_clear_wake_irq(port->dev);
}

static void omap_8250_throttle(struct uart_port *port)
@@ -1451,8 +1443,6 @@ static int omap8250_probe(struct platform_device *pdev)
&up.overrun_backoff_time_ms) != 0)
up.overrun_backoff_time_ms = 0;

- priv->wakeirq = irq_of_parse_and_map(np, 1);
-
pdata = of_device_get_match_data(&pdev->dev);
if (pdata)
priv->habit |= pdata->habit;
@@ -1530,6 +1520,15 @@ static int omap8250_probe(struct platform_device *pdev)
}
}
#endif
+
+ irq_set_status_flags(irq, IRQ_NOAUTOEN);
+ ret = devm_request_irq(&pdev->dev, irq, omap8250_irq, 0,
+ dev_name(&pdev->dev), priv);
+ if (ret < 0)
+ return ret;
+
+ priv->wakeirq = irq_of_parse_and_map(np, 1);
+
ret = serial8250_register_8250_port(&up);
if (ret < 0) {
dev_err(&pdev->dev, "unable to register 8250 port\n");
--
2.40.1