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 84a9582fd203 ("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: Tony Lindgren <tony@xxxxxxxxxxx> --- Changes since v1: - Fix build warning if CONFIG_SERIAL_8250_DMA is not set as reported by kernel test robot --- drivers/tty/serial/8250/8250_omap.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 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 @@ -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); @@ -1743,6 +1749,7 @@ 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; } @@ -1752,6 +1759,10 @@ 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); @@ -1767,8 +1778,10 @@ 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; } -- 2.42.0