[PATCH v4 1/5] tty: serial: sh-sci: Fix transmit end interrupt handler

[Biju Das <biju.das.jz@bp.renesas.com>]

The fourth interrupt on SCI port is transmit end interrupt compared to
the break interrupt on other port types. So, shuffle the interrupts to fix
the transmit end interrupt handler.

Fixes: e1d0be616186 ("sh-sci: Add h8300 SCI")
Cc: stable@vger.kernel.org
Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v3->v4:
 * No change.
v2->v3:
 * Cced stable@vger.kernel.org
v1->v2:
 * Replaced the wrong fixes tag
 * Added a simpler check in sci_init_single() and added a check in
   probe to catch invalid interrupt count.
Tested the SCI0 interface on RZ/G2UL by connecting to PMOD USBUART.
 39:          0     GICv3 437 Level     1004d000.serial:rx err
 40:         12     GICv3 438 Edge      1004d000.serial:rx full
 41:         70     GICv3 439 Edge      1004d000.serial:tx empty
 42:         18     GICv3 440 Level     1004d000.serial:tx end
---
 drivers/tty/serial/sh-sci.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index af4a7a865764..616041faab55 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -31,6 +31,7 @@
 #include <linux/ioport.h>
 #include <linux/ktime.h>
 #include <linux/major.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/of.h>
@@ -2864,6 +2865,13 @@ static int sci_init_single(struct platform_device *dev,
 			sci_port->irqs[i] = platform_get_irq(dev, i);
 	}
 
+	/*
+	 * The fourth interrupt on SCI port is transmit end interrupt, so
+	 * shuffle the interrupts.
+	 */
+	if (p->type == PORT_SCI)
+		swap(sci_port->irqs[SCIx_BRI_IRQ], sci_port->irqs[SCIx_TEI_IRQ]);
+
 	/* The SCI generates several interrupts. They can be muxed together or
 	 * connected to different interrupt lines. In the muxed case only one
 	 * interrupt resource is specified as there is only one interrupt ID.
-- 
2.25.1