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From:   =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
To:     linux-serial@vger.kernel.org, Greg KH <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Paul Cercueil <paul@crapouillou.net>,
        linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Lukas Wunner <lukas@wunner.de>,
        =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= 
        <u.kleine-koenig@pengutronix.de>,
        Lino Sanfilippo <LinoSanfilippo@gmx.de>,
        =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH v9 1/6] serial: 8250: make saved LSR larger
Date:   Fri, 24 Jun 2022 23:42:05 +0300
Message-Id: <20220624204210.11112-2-ilpo.jarvinen@linux.intel.com>
In-Reply-To: <20220624204210.11112-1-ilpo.jarvinen@linux.intel.com>
References: <20220624204210.11112-1-ilpo.jarvinen@linux.intel.com>
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DW flags address received as BIT(8) in LSR. In order to not lose that
on read, enlarge lsr_saved_flags to u16.

Adjust lsr/status variables and related call chains to use u16.
Technically, some of these type conversion would not be needed but it
doesn't hurt to be consistent.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/8250/8250.h         |  4 ++--
 drivers/tty/serial/8250/8250_exar.c    |  2 +-
 drivers/tty/serial/8250/8250_fsl.c     |  2 +-
 drivers/tty/serial/8250/8250_ingenic.c |  2 +-
 drivers/tty/serial/8250/8250_omap.c    |  7 +++----
 drivers/tty/serial/8250/8250_port.c    | 17 +++++++++--------
 include/linux/serial_8250.h            |  6 +++---
 7 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index b120da57c61f..0ff5688ba90c 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -133,9 +133,9 @@ static inline void serial_out(struct uart_8250_port *up, int offset, int value)
  *
  *	Returns LSR value or'ed with the preserved flags (if any).
  */
-static inline unsigned int serial_lsr_in(struct uart_8250_port *up)
+static inline u16 serial_lsr_in(struct uart_8250_port *up)
 {
-	unsigned int lsr = up->lsr_saved_flags;
+	u16 lsr = up->lsr_saved_flags;
 
 	lsr |= serial_in(up, UART_LSR);
 	up->lsr_saved_flags = lsr & LSR_SAVE_FLAGS;
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 528779b40049..3d999eec4087 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -195,11 +195,11 @@ static int xr17v35x_startup(struct uart_port *port)
 
 static void exar_shutdown(struct uart_port *port)
 {
-	unsigned char lsr;
 	bool tx_complete = false;
 	struct uart_8250_port *up = up_to_u8250p(port);
 	struct circ_buf *xmit = &port->state->xmit;
 	int i = 0;
+	u16 lsr;
 
 	do {
 		lsr = serial_in(up, UART_LSR);
diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c
index 9c01c531349d..fd4005fcd0d6 100644
--- a/drivers/tty/serial/8250/8250_fsl.c
+++ b/drivers/tty/serial/8250/8250_fsl.c
@@ -25,8 +25,8 @@
 
 int fsl8250_handle_irq(struct uart_port *port)
 {
-	unsigned char lsr, orig_lsr;
 	unsigned long flags;
+	u16 lsr, orig_lsr;
 	unsigned int iir;
 	struct uart_8250_port *up = up_to_u8250p(port);
 
diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
index cff91aa03f29..2b2f5d8d24b9 100644
--- a/drivers/tty/serial/8250/8250_ingenic.c
+++ b/drivers/tty/serial/8250/8250_ingenic.c
@@ -54,7 +54,7 @@ static void early_out(struct uart_port *port, int offset, uint8_t value)
 
 static void ingenic_early_console_putc(struct uart_port *port, unsigned char c)
 {
-	uint8_t lsr;
+	u16 lsr;
 
 	do {
 		lsr = early_in(port, UART_LSR);
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index ac8bfa042391..0dcecbbc3967 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -1115,8 +1115,7 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
 	return omap_8250_rx_dma(up);
 }
 
-static unsigned char omap_8250_handle_rx_dma(struct uart_8250_port *up,
-					     u8 iir, unsigned char status)
+static u16 omap_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, u16 status)
 {
 	if ((status & (UART_LSR_DR | UART_LSR_BI)) &&
 	    (iir & UART_IIR_RDI)) {
@@ -1130,7 +1129,7 @@ static unsigned char omap_8250_handle_rx_dma(struct uart_8250_port *up,
 }
 
 static void am654_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir,
-				     unsigned char status)
+				     u16 status)
 {
 	/*
 	 * Queue a new transfer if FIFO has data.
@@ -1164,7 +1163,7 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	struct omap8250_priv *priv = up->port.private_data;
-	unsigned char status;
+	u16 status;
 	u8 iir;
 
 	serial8250_rpm_get(up);
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index c860f5964138..19c612d732cf 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1508,7 +1508,7 @@ static inline void __stop_tx(struct uart_8250_port *p)
 	struct uart_8250_em485 *em485 = p->em485;
 
 	if (em485) {
-		unsigned char lsr = serial_lsr_in(p);
+		u16 lsr = serial_lsr_in(p);
 		u64 stop_delay = 0;
 
 		if (!(lsr & UART_LSR_THRE))
@@ -1565,7 +1565,7 @@ static inline void __start_tx(struct uart_port *port)
 
 	if (serial8250_set_THRI(up)) {
 		if (up->bugs & UART_BUG_TXEN) {
-			unsigned char lsr = serial_lsr_in(up);
+			u16 lsr = serial_lsr_in(up);
 
 			if (lsr & UART_LSR_THRE)
 				serial8250_tx_chars(up);
@@ -1719,7 +1719,7 @@ static void serial8250_enable_ms(struct uart_port *port)
 	serial8250_rpm_put(up);
 }
 
-void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
+void serial8250_read_char(struct uart_8250_port *up, u16 lsr)
 {
 	struct uart_port *port = &up->port;
 	unsigned char ch;
@@ -1788,7 +1788,7 @@ EXPORT_SYMBOL_GPL(serial8250_read_char);
  * (such as THRE) because the LSR value might come from an already consumed
  * character.
  */
-unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
+u16 serial8250_rx_chars(struct uart_8250_port *up, u16 lsr)
 {
 	struct uart_port *port = &up->port;
 	int max_count = 256;
@@ -1908,10 +1908,10 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
  */
 int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 {
-	unsigned char status;
 	struct uart_8250_port *up = up_to_u8250p(port);
 	bool skip_rx = false;
 	unsigned long flags;
+	u16 status;
 
 	if (iir & UART_IIR_NO_INT)
 		return 0;
@@ -1994,7 +1994,7 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	unsigned long flags;
-	unsigned int lsr;
+	u16 lsr;
 
 	serial8250_rpm_get(up);
 
@@ -2117,8 +2117,8 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
 static int serial8250_get_poll_char(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
-	unsigned char lsr;
 	int status;
+	u16 lsr;
 
 	serial8250_rpm_get(up);
 
@@ -2173,8 +2173,9 @@ int serial8250_do_startup(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	unsigned long flags;
-	unsigned char lsr, iir;
+	unsigned char iir;
 	int retval;
+	u16 lsr;
 
 	if (!port->fifosize)
 		port->fifosize = uart_config[port->type].fifo_size;
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index ff84a3ed10ea..4565f25ba9a2 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -119,7 +119,7 @@ struct uart_8250_port {
 	 * be immediately processed.
 	 */
 #define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
-	unsigned char		lsr_saved_flags;
+	u16			lsr_saved_flags;
 #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
 	unsigned char		msr_saved_flags;
 
@@ -170,8 +170,8 @@ extern void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
 				      unsigned int quot_frac);
 extern int fsl8250_handle_irq(struct uart_port *port);
 int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
-unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr);
-void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr);
+u16 serial8250_rx_chars(struct uart_8250_port *up, u16 lsr);
+void serial8250_read_char(struct uart_8250_port *up, u16 lsr);
 void serial8250_tx_chars(struct uart_8250_port *up);
 unsigned int serial8250_modem_status(struct uart_8250_port *up);
 void serial8250_init_port(struct uart_8250_port *up);
-- 
2.30.2