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From:   Jiri Slaby <jslaby@suse.cz>
To:     gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiri Slaby <jslaby@suse.cz>,
        Tobias Klauser <tklauser@distanz.ch>
Subject: [PATCH 3/4] tty: serial: unify TX space reads under altera_jtaguart_tx_space()
Date:   Tue, 27 Sep 2022 13:18:18 +0200
Message-Id: <20220927111819.18516-3-jslaby@suse.cz>
In-Reply-To: <20220927111819.18516-1-jslaby@suse.cz>
References: <20220927111819.18516-1-jslaby@suse.cz>
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TX space reads from the control register are performed in various forms
on 4 places in altera_jtaguart. Unify all those and do the read and
masking on a single place.

The new helper altera_jtaguart_tx_space() uses FIELD_GET(), so we can
drop ALTERA_JTAGUART_CONTROL_WSPACE_OFF now.

Cc: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/serial/altera_jtaguart.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c
index 23f339757894..ac8ce418de36 100644
--- a/drivers/tty/serial/altera_jtaguart.c
+++ b/drivers/tty/serial/altera_jtaguart.c
@@ -9,6 +9,7 @@
  * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
  */
 
+#include <linux/bitfield.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
@@ -48,7 +49,6 @@
 #define ALTERA_JTAGUART_CONTROL_WI_MSK		0x00000200
 #define ALTERA_JTAGUART_CONTROL_AC_MSK		0x00000400
 #define ALTERA_JTAGUART_CONTROL_WSPACE_MSK	0xFFFF0000
-#define ALTERA_JTAGUART_CONTROL_WSPACE_OFF	16
 
 /*
  * Local per-uart structure.
@@ -59,10 +59,19 @@ struct altera_jtaguart {
 	unsigned long imr;	/* Local IMR mirror */
 };
 
+static unsigned int altera_jtaguart_tx_space(struct uart_port *port, u32 *ctlp)
+{
+	u32 ctl = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG);
+
+	if (ctlp)
+		*ctlp = ctl;
+
+	return FIELD_GET(ALTERA_JTAGUART_CONTROL_WSPACE_MSK, ctl);
+}
+
 static unsigned int altera_jtaguart_tx_empty(struct uart_port *port)
 {
-	return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
-		ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0;
+	return altera_jtaguart_tx_space(port, NULL) ? TIOCSER_TEMT : 0;
 }
 
 static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port)
@@ -150,9 +159,7 @@ static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp)
 
 	pending = uart_circ_chars_pending(xmit);
 	if (pending > 0) {
-		count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
-				ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >>
-			ALTERA_JTAGUART_CONTROL_WSPACE_OFF;
+		count = altera_jtaguart_tx_space(port, NULL);
 		if (count > pending)
 			count = pending;
 		if (count > 0) {
@@ -298,12 +305,11 @@ static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];
 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
 static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c)
 {
-	unsigned long status;
 	unsigned long flags;
+	u32 status;
 
 	spin_lock_irqsave(&port->lock, flags);
-	while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) &
-		ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
+	while (!altera_jtaguart_tx_space(port, &status)) {
 		if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
 			spin_unlock_irqrestore(&port->lock, flags);
 			return;	/* no connection activity */
@@ -321,8 +327,7 @@ static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c
 	unsigned long flags;
 
 	spin_lock_irqsave(&port->lock, flags);
-	while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
-		ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
+	while (!altera_jtaguart_tx_space(port, NULL)) {
 		spin_unlock_irqrestore(&port->lock, flags);
 		cpu_relax();
 		spin_lock_irqsave(&port->lock, flags);
-- 
2.37.3