linux-kernel - [RFC/PATCH 07/13] serial: omap: simplify IRQ handling

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Message-Id: <1345540555-24359-8-git-send-email-balbi@ti.com>
Date:	Tue, 21 Aug 2012 12:15:49 +0300
From:	Felipe Balbi <balbi@...com>
To:	alan@...ux.intel.com
Cc:	Tony Lindgren <tony@...mide.com>, Kevin Hilman <khilman@...com>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux ARM Kernel Mailing List 
	<linux-arm-kernel@...ts.infradead.org>,
	linux-serial@...r.kernel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Shubhrajyoti Datta <shubhrajyoti@...com>,
	Felipe Balbi <balbi@...com>
Subject: [RFC/PATCH 07/13] serial: omap: simplify IRQ handling

quite a few changes here, though they are
pretty obvious. In summary we're making sure
to detect which interrupt type we need to
handle before calling the underlying interrupt
handling procedure.

Signed-off-by: Felipe Balbi <balbi@...com>
---
 drivers/tty/serial/omap-serial.c | 47 ++++++++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 4d74a9b..1ca08b8 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -350,32 +350,55 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
 {
 	struct uart_omap_port *up = dev_id;
 	unsigned int iir, lsr;
+	unsigned int type;
 	unsigned long flags;
 
+	spin_lock_irqsave(&up->port.lock, flags);
 	pm_runtime_get_sync(up->dev);
 	iir = serial_in(up, UART_IIR);
-	if (iir & UART_IIR_NO_INT) {
-		pm_runtime_mark_last_busy(up->dev);
-		pm_runtime_put_autosuspend(up->dev);
-		return IRQ_HANDLED;
-	}
+again:
+	if (iir & UART_IIR_NO_INT)
+		goto out;
 
-	spin_lock_irqsave(&up->port.lock, flags);
 	lsr = serial_in(up, UART_LSR);
-	if (iir & UART_IIR_RLSI) {
+
+	/* extract IRQ type from IIR register */
+	type = iir & 0x3e;
+
+	switch (type) {
+	case UART_IIR_MSI:
+		check_modem_status(up);
+		break;
+	case UART_IIR_THRI:
+		if (lsr & UART_LSR_THRE)
+			transmit_chars(up);
+		break;
+	case UART_IIR_RDI:
 		if (lsr & UART_LSR_DR)
 			receive_chars(up, &lsr);
+		break;
+	case UART_IIR_RLSI:
+		if (lsr & UART_LSR_BRK_ERROR_BITS)
+			receive_chars(up, &lsr);
+		break;
+	case UART_IIR_RX_TIMEOUT:
+		receive_chars(up, &lsr);
+		break;
+	case UART_IIR_CTS_RTS_DSR:
+		iir = serial_in(up, UART_IIR);
+		goto again;
+	case UART_IIR_XOFF:
+		/* FALLTHROUGH */
+	default:
+		break;
 	}
 
-	check_modem_status(up);
-	if ((lsr & UART_LSR_THRE) && (iir & UART_IIR_THRI))
-		transmit_chars(up);
-
+out:
 	spin_unlock_irqrestore(&up->port.lock, flags);
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
-
 	up->port_activity = jiffies;
+
 	return IRQ_HANDLED;
 }
 
-- 
1.7.12.rc3

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