linux-kernel - [PATCH 6/7] serial: 8250_omap: Drop the use of pm_runtime_irq

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Message-Id: <20211115084203.56478-7-tony@atomide.com>
Date:   Mon, 15 Nov 2021 10:42:02 +0200
From:   Tony Lindgren <tony@...mide.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...el.com>,
        Jiri Slaby <jirislaby@...nel.org>,
        Johan Hovold <johan@...nel.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-serial@...r.kernel.org, linux-omap@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH 6/7] serial: 8250_omap: Drop the use of pm_runtime_irq_safe()

We can finally drop the pm_runtime_irq_safe() usage for 8250_omap driver.

We already have the serial layer RX wake path fixed for power management.
We no longer allow deeper idle states unless the kernel console has been
detached, and we require that the RX wakeirq is configured.

For TX path, we now use the prep_tx() and uart_flush_tx() calls.

To drop pm_runtime_irq_safe(), we remove all PM runtime calls from the
interrupt context. If we ever see an interrupt for an idled port, we just
bail out.

Signed-off-by: Tony Lindgren <tony@...mide.com>
---
 drivers/tty/serial/8250/8250_omap.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 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
@@ -621,6 +621,9 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
 	unsigned int iir, lsr;
 	int ret;
 
+	if (port->runtime_suspended)
+		return IRQ_NONE;
+
 #ifdef CONFIG_SERIAL_8250_DMA
 	if (up->dma) {
 		ret = omap_8250_dma_handle_irq(port);
@@ -628,7 +631,6 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
 	}
 #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);
@@ -662,8 +664,6 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
 		schedule_delayed_work(&up->overrun_backoff, delay);
 	}
 
-	serial8250_rpm_put(up);
-
 	return IRQ_RETVAL(ret);
 }
 
@@ -1191,13 +1191,9 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
 	unsigned char status;
 	u8 iir;
 
-	serial8250_rpm_get(up);
-
 	iir = serial_port_in(port, UART_IIR);
-	if (iir & UART_IIR_NO_INT) {
-		serial8250_rpm_put(up);
+	if (iir & UART_IIR_NO_INT)
 		return IRQ_HANDLED;
-	}
 
 	spin_lock(&port->lock);
 
@@ -1226,7 +1222,6 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
 
 	uart_unlock_and_check_sysrq(port);
 
-	serial8250_rpm_put(up);
 	return 1;
 }
 
@@ -1420,8 +1415,6 @@ 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);
-- 
2.33.1