Commit 8700a7ea authored by Tony Lindgren's avatar Tony Lindgren Committed by Greg Kroah-Hartman
Browse files

serial: 8250_omap: Drop pm_runtime_irq_safe() 



Let's drop the use of pm_runtime_irq_safe() for 8250_omap. The use of
pm_runtime_irq_safe() is not nice as it takes a permanent usage count on
the parent device.

We can finally drop pm_runtime_irq_safe() safely as the kernel now knows
when the uart port tx is active. This changed with commit 84a9582f
("serial: core: Start managing serial controllers to enable runtime PM").

For serial port rx, we already use Linux generic wakeirqs for 8250_omap.

To drop pm_runtime_irq_safe(), we need to add handling for shallow idle
state where the port hardware may already be awake and an IO interrupt
happens. We also need to replace the serial8250_rpm sync calls in the
interrupt handlers with async runtime PM calls.

Note that omap8250_irq() calls omap_8250_dma_handle_irq(), so we don't
need separate runtime PM calls in omap_8250_dma_handle_irq().

While at it, let's also add the missing line break to the end of
omap8250_runtime_resume() to group the calls.

Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20231004062650.64487-1-tony@atomide.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b9cbe7e8

drivers/tty/serial/8250/8250_omap.c

+21 −8
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
 *

 */



#include <linux/atomic.h>

#include <linux/clk.h>

#include <linux/device.h>

#include <linux/io.h>
@@ -130,6 +131,7 @@ struct omap8250_priv { 


	u8 tx_trigger;

	u8 rx_trigger;

	atomic_t active;

	bool is_suspending;

	int wakeirq;

	int wakeups_enabled;
@@ -632,14 +634,23 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id) 
	unsigned int iir, lsr;

	int ret;



	pm_runtime_get_noresume(port->dev);



	/* Shallow idle state wake-up to an IO interrupt? */

	if (atomic_add_unless(&priv->active, 1, 1)) {

		priv->latency = priv->calc_latency;

		schedule_work(&priv->qos_work);

	}



#ifdef CONFIG_SERIAL_8250_DMA

	if (up->dma) {

		ret = omap_8250_dma_handle_irq(port);

		pm_runtime_mark_last_busy(port->dev);

		pm_runtime_put(port->dev);

		return IRQ_RETVAL(ret);

	}

#endif



	serial8250_rpm_get(up);

	lsr = serial_port_in(port, UART_LSR);

	iir = serial_port_in(port, UART_IIR);

	ret = serial8250_handle_irq(port, iir);
@@ -676,7 +687,8 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id) 
		schedule_delayed_work(&up->overrun_backoff, delay);

	}



	serial8250_rpm_put(up);

	pm_runtime_mark_last_busy(port->dev);

	pm_runtime_put(port->dev);



	return IRQ_RETVAL(ret);

}
@@ -1270,11 +1282,8 @@ static int omap_8250_dma_handle_irq(struct uart_port *port) 
	u16 status;

	u8 iir;



	serial8250_rpm_get(up);



	iir = serial_port_in(port, UART_IIR);

	if (iir & UART_IIR_NO_INT) {

		serial8250_rpm_put(up);

		return IRQ_HANDLED;

	}
@@ -1305,7 +1314,6 @@ static int omap_8250_dma_handle_irq(struct uart_port *port) 


	uart_unlock_and_check_sysrq(port);



	serial8250_rpm_put(up);

	return 1;

}
@@ -1503,8 +1511,6 @@ static int omap8250_probe(struct platform_device *pdev) 
	if (!of_get_available_child_count(pdev->dev.of_node))

		pm_runtime_set_autosuspend_delay(&pdev->dev, -1);



	pm_runtime_irq_safe(&pdev->dev);



	pm_runtime_get_sync(&pdev->dev);



	omap_serial_fill_features_erratas(&up, priv);
@@ -1748,6 +1754,7 @@ static int omap8250_runtime_suspend(struct device *dev) 


	priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;

	schedule_work(&priv->qos_work);

	atomic_set(&priv->active, 0);



	return 0;

}
@@ -1757,6 +1764,10 @@ static int omap8250_runtime_resume(struct device *dev) 
	struct omap8250_priv *priv = dev_get_drvdata(dev);

	struct uart_8250_port *up = NULL;



	/* Did the hardware wake to a device IO interrupt before a wakeirq? */

	if (atomic_read(&priv->active))

		return 0;



	if (priv->line >= 0)

		up = serial8250_get_port(priv->line);
@@ -1772,8 +1783,10 @@ static int omap8250_runtime_resume(struct device *dev) 
		uart_port_unlock_irq(&up->port);

	}



	atomic_set(&priv->active, 1);

	priv->latency = priv->calc_latency;

	schedule_work(&priv->qos_work);



	return 0;

}