linux-kernel - [RT,1/1] tty/serial/sifive: Make the locking RT aware

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Message-Id: <20241203094009.67697-1-ende.tan@starfivetech.com>
Date: Tue,  3 Dec 2024 17:40:09 +0800
From: ende.tan@...rfivetech.com
To: linux-kernel@...r.kernel.org
Cc: bigeasy@...utronix.de,
	tglx@...utronix.de,
	rostedt@...dmis.org,
	linux-rt-users@...r.kernel.org,
	leyfoon.tan@...rfivetech.com,
	endeneer@...il.com,
	Tan En De <ende.tan@...rfivetech.com>
Subject: [RT,1/1] tty/serial/sifive: Make the locking RT aware

From: Tan En De <ende.tan@...rfivetech.com>

The lock is a sleeping lock and local_irq_save() is not the optimsation
we are looking for. Redo it to make it work on -RT and non-RT.

Signed-off-by: Tan En De <ende.tan@...rfivetech.com>
Signed-off-by: Tan Ley Foon <leyfoon.tan@...rfivetech.com>
---
 drivers/tty/serial/sifive.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index b296e57a9dee..074c9f392634 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -791,13 +791,10 @@ static void sifive_serial_console_write(struct console *co, const char *s,
 	if (!ssp)
 		return;
 
-	local_irq_save(flags);
-	if (ssp->port.sysrq)
-		locked = 0;
-	else if (oops_in_progress)
-		locked = uart_port_trylock(&ssp->port);
+	if (ssp->port.sysrq || oops_in_progress)
+		locked = uart_port_trylock_irqsave(&ssp->port, &flags);
 	else
-		uart_port_lock(&ssp->port);
+		uart_port_lock_irqsave(&ssp->port, &flags);
 
 	ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS);
 	__ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp);
@@ -807,8 +804,7 @@ static void sifive_serial_console_write(struct console *co, const char *s,
 	__ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp);
 
 	if (locked)
-		uart_port_unlock(&ssp->port);
-	local_irq_restore(flags);
+		uart_port_unlock_irqrestore(&ssp->port, flags);
 }
 
 static int sifive_serial_console_setup(struct console *co, char *options)
-- 
2.34.1