1 files changed, 71 insertions, 86 deletions

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 3c36a06a20b0..39b35a61958c 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -50,8 +50,6 @@
 #define DEBUG_AUTOCONF(fmt...)	do { } while (0)
 #endif
 
-#define BOTH_EMPTY	(UART_LSR_TEMT | UART_LSR_THRE)
-
 /*
  * Here we define the default xmit fifo size used for each type of UART.
  */
@@ -336,27 +334,29 @@ static void default_serial_dl_write(struct uart_8250_port *up, int value)
 
 #ifdef CONFIG_SERIAL_8250_RT288X
 
+#define UART_REG_UNMAPPED	-1
+
 /* Au1x00/RT288x UART hardware has a weird register layout */
 static const s8 au_io_in_map[8] = {
-	 0,	/* UART_RX  */
-	 2,	/* UART_IER */
-	 3,	/* UART_IIR */
-	 5,	/* UART_LCR */
-	 6,	/* UART_MCR */
-	 7,	/* UART_LSR */
-	 8,	/* UART_MSR */
-	-1,	/* UART_SCR (unmapped) */
+	[UART_RX]	= 0,
+	[UART_IER]	= 2,
+	[UART_IIR]	= 3,
+	[UART_LCR]	= 5,
+	[UART_MCR]	= 6,
+	[UART_LSR]	= 7,
+	[UART_MSR]	= 8,
+	[UART_SCR]	= UART_REG_UNMAPPED,
 };
 
 static const s8 au_io_out_map[8] = {
-	 1,	/* UART_TX  */
-	 2,	/* UART_IER */
-	 4,	/* UART_FCR */
-	 5,	/* UART_LCR */
-	 6,	/* UART_MCR */
-	-1,	/* UART_LSR (unmapped) */
-	-1,	/* UART_MSR (unmapped) */
-	-1,	/* UART_SCR (unmapped) */
+	[UART_TX]	= 1,
+	[UART_IER]	= 2,
+	[UART_FCR]	= 4,
+	[UART_LCR]	= 5,
+	[UART_MCR]	= 6,
+	[UART_LSR]	= UART_REG_UNMAPPED,
+	[UART_MSR]	= UART_REG_UNMAPPED,
+	[UART_SCR]	= UART_REG_UNMAPPED,
 };
 
 unsigned int au_serial_in(struct uart_port *p, int offset)
@@ -364,7 +364,7 @@ unsigned int au_serial_in(struct uart_port *p, int offset)
 	if (offset >= ARRAY_SIZE(au_io_in_map))
 		return UINT_MAX;
 	offset = au_io_in_map[offset];
-	if (offset < 0)
+	if (offset == UART_REG_UNMAPPED)
 		return UINT_MAX;
 	return __raw_readl(p->membase + (offset << p->regshift));
 }
@@ -374,7 +374,7 @@ void au_serial_out(struct uart_port *p, int offset, int value)
 	if (offset >= ARRAY_SIZE(au_io_out_map))
 		return;
 	offset = au_io_out_map[offset];
-	if (offset < 0)
+	if (offset == UART_REG_UNMAPPED)
 		return;
 	__raw_writel(value, p->membase + (offset << p->regshift));
 }
@@ -647,6 +647,14 @@ void serial8250_em485_destroy(struct uart_8250_port *p)
 }
 EXPORT_SYMBOL_GPL(serial8250_em485_destroy);
 
+struct serial_rs485 serial8250_em485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
+		 SER_RS485_TERMINATE_BUS | SER_RS485_RX_DURING_TX,
+	.delay_rts_before_send = 1,
+	.delay_rts_after_send = 1,
+};
+EXPORT_SYMBOL_GPL(serial8250_em485_supported);
+
 /**
  * serial8250_em485_config() - generic ->rs485_config() callback
  * @port: uart port
@@ -656,7 +664,8 @@ EXPORT_SYMBOL_GPL(serial8250_em485_destroy);
  * if the uart is incapable of driving RTS as a Transmit Enable signal in
  * hardware, relying on software emulation instead.
  */
-int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485)
+int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
+			    struct serial_rs485 *rs485)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
@@ -667,29 +676,12 @@ int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485)
 		rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
 	}
 
-	/* clamp the delays to [0, 100ms] */
-	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
-	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);
-
-	memset(rs485->padding, 0, sizeof(rs485->padding));
-	port->rs485 = *rs485;
-
-	gpiod_set_value(port->rs485_term_gpio,
-			rs485->flags & SER_RS485_TERMINATE_BUS);
-
 	/*
 	 * Both serial8250_em485_init() and serial8250_em485_destroy()
 	 * are idempotent.
 	 */
-	if (rs485->flags & SER_RS485_ENABLED) {
-		int ret = serial8250_em485_init(up);
-
-		if (ret) {
-			rs485->flags &= ~SER_RS485_ENABLED;
-			port->rs485.flags &= ~SER_RS485_ENABLED;
-		}
-		return ret;
-	}
+	if (rs485->flags & SER_RS485_ENABLED)
+		return serial8250_em485_init(up);
 
 	serial8250_em485_destroy(up);
 	return 0;
@@ -849,7 +841,7 @@ static int size_fifo(struct uart_8250_port *up)
 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
 	old_dl = serial_dl_read(up);
 	serial_dl_write(up, 0x0001);
-	serial_out(up, UART_LCR, 0x03);
+	serial_out(up, UART_LCR, UART_LCR_WLEN8);
 	for (count = 0; count < 256; count++)
 		serial_out(up, UART_TX, count);
 	mdelay(20);/* FIXME - schedule_timeout */
@@ -1503,18 +1495,12 @@ static void __stop_tx_rs485(struct uart_8250_port *p, u64 stop_delay)
 	}
 }
 
-static inline void __do_stop_tx(struct uart_8250_port *p)
-{
-	if (serial8250_clear_THRI(p))
-		serial8250_rpm_put_tx(p);
-}
-
 static inline void __stop_tx(struct uart_8250_port *p)
 {
 	struct uart_8250_em485 *em485 = p->em485;
 
 	if (em485) {
-		unsigned char lsr = serial_in(p, UART_LSR);
+		u16 lsr = serial_lsr_in(p);
 		u64 stop_delay = 0;
 
 		p->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
@@ -1522,7 +1508,7 @@ static inline void __stop_tx(struct uart_8250_port *p)
 		if (!(lsr & UART_LSR_THRE))
 			return;
 		/*
-		 * To provide required timeing and allow FIFO transfer,
+		 * To provide required timing and allow FIFO transfer,
 		 * __stop_tx_rs485() must be called only when both FIFO and
 		 * shift register are empty. The device driver should either
 		 * enable interrupt on TEMT or set UART_CAP_NOTEMT that will
@@ -1544,7 +1530,9 @@ static inline void __stop_tx(struct uart_8250_port *p)
 
 		__stop_tx_rs485(p, stop_delay);
 	}
-	__do_stop_tx(p);
+
+	if (serial8250_clear_THRI(p))
+		serial8250_rpm_put_tx(p);
 }
 
 static void serial8250_stop_tx(struct uart_port *port)
@@ -1573,10 +1561,8 @@ static inline void __start_tx(struct uart_port *port)
 
 	if (serial8250_set_THRI(up)) {
 		if (up->bugs & UART_BUG_TXEN) {
-			unsigned char lsr;
+			u16 lsr = serial_lsr_in(up);
 
-			lsr = serial_in(up, UART_LSR);
-			up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
 			if (lsr & UART_LSR_THRE)
 				serial8250_tx_chars(up);
 		}
@@ -1616,7 +1602,8 @@ void serial8250_em485_start_tx(struct uart_8250_port *up)
 }
 EXPORT_SYMBOL_GPL(serial8250_em485_start_tx);
 
-static inline void start_tx_rs485(struct uart_port *port)
+/* Returns false, if start_tx_timer was setup to defer TX start */
+static bool start_tx_rs485(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	struct uart_8250_em485 *em485 = up->em485;
@@ -1644,11 +1631,11 @@ static inline void start_tx_rs485(struct uart_port *port)
 			em485->active_timer = &em485->start_tx_timer;
 			start_hrtimer_ms(&em485->start_tx_timer,
 					 up->port.rs485.delay_rts_before_send);
-			return;
+			return false;
 		}
 	}
 
-	__start_tx(port);
+	return true;
 }
 
 static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
@@ -1678,14 +1665,12 @@ static void serial8250_start_tx(struct uart_port *port)
 
 	serial8250_rpm_get_tx(up);
 
-	if (em485 &&
-	    em485->active_timer == &em485->start_tx_timer)
-		return;
-
-	if (em485)
-		start_tx_rs485(port);
-	else
-		__start_tx(port);
+	if (em485) {
+		if ((em485->active_timer == &em485->start_tx_timer) ||
+		    !start_tx_rs485(port))
+			return;
+	}
+	__start_tx(port);
 }
 
 static void serial8250_throttle(struct uart_port *port)
@@ -1729,7 +1714,7 @@ 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;
@@ -1792,11 +1777,13 @@ void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
 EXPORT_SYMBOL_GPL(serial8250_read_char);
 
 /*
- * serial8250_rx_chars: processes according to the passed in LSR
- * value, and returns the remaining LSR bits not handled
- * by this Rx routine.
+ * serial8250_rx_chars - Read characters. The first LSR value must be passed in.
+ *
+ * Returns LSR bits. The caller should rely only on non-Rx related LSR bits
+ * (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;
@@ -1852,7 +1839,7 @@ void serial8250_tx_chars(struct uart_8250_port *up)
 		if (uart_circ_empty(xmit))
 			break;
 		if ((up->capabilities & UART_CAP_HFIFO) &&
-		    (serial_in(up, UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY)
+		    !uart_lsr_tx_empty(serial_in(up, UART_LSR)))
 			break;
 		/* The BCM2835 MINI UART THRE bit is really a not-full bit. */
 		if ((up->capabilities & UART_CAP_MINI) &&
@@ -1916,17 +1903,17 @@ 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;
 
 	spin_lock_irqsave(&port->lock, flags);
 
-	status = serial_port_in(port, UART_LSR);
+	status = serial_lsr_in(up);
 
 	/*
 	 * If port is stopped and there are no error conditions in the
@@ -2002,18 +1989,17 @@ 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);
 
 	spin_lock_irqsave(&port->lock, flags);
-	lsr = serial_port_in(port, UART_LSR);
-	up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+	lsr = serial_lsr_in(up);
 	spin_unlock_irqrestore(&port->lock, flags);
 
 	serial8250_rpm_put(up);
 
-	return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
+	return uart_lsr_tx_empty(lsr) ? TIOCSER_TEMT : 0;
 }
 
 unsigned int serial8250_do_get_mctrl(struct uart_port *port)
@@ -2084,9 +2070,7 @@ static void wait_for_lsr(struct uart_8250_port *up, int bits)
 
 	/* Wait up to 10ms for the character(s) to be sent. */
 	for (;;) {
-		status = serial_in(up, UART_LSR);
-
-		up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
+		status = serial_lsr_in(up);
 
 		if ((status & bits) == bits)
 			break;
@@ -2128,8 +2112,8 @@ 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);
 
@@ -2163,7 +2147,7 @@ static void serial8250_put_poll_char(struct uart_port *port,
 	else
 		serial_port_out(port, UART_IER, 0);
 
-	wait_for_xmitr(up, BOTH_EMPTY);
+	wait_for_xmitr(up, UART_LSR_BOTH_EMPTY);
 	/*
 	 *	Send the character out.
 	 */
@@ -2173,7 +2157,7 @@ static void serial8250_put_poll_char(struct uart_port *port,
 	 *	Finally, wait for transmitter to become empty
 	 *	and restore the IER
 	 */
-	wait_for_xmitr(up, BOTH_EMPTY);
+	wait_for_xmitr(up, UART_LSR_BOTH_EMPTY);
 	serial_port_out(port, UART_IER, ier);
 	serial8250_rpm_put(up);
 }
@@ -2184,8 +2168,9 @@ 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;
@@ -2810,7 +2795,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
 		port->read_status_mask |= UART_LSR_BI;
 
 	/*
-	 * Characteres to ignore
+	 * Characters to ignore
 	 */
 	port->ignore_status_mask = 0;
 	if (termios->c_iflag & IGNPAR)
@@ -3203,7 +3188,7 @@ static void serial8250_config_port(struct uart_port *port, int flags)
 		autoconfig(up);
 
 	if (port->rs485.flags & SER_RS485_ENABLED)
-		port->rs485_config(port, &port->rs485);
+		uart_rs485_config(port);
 
 	/* if access method is AU, it is a 16550 with a quirk */
 	if (port->type == PORT_16550A && port->iotype == UPIO_AU)
@@ -3445,7 +3430,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 	 *	Finally, wait for transmitter to become empty
 	 *	and restore the IER
 	 */
-	wait_for_xmitr(up, BOTH_EMPTY);
+	wait_for_xmitr(up, UART_LSR_BOTH_EMPTY);
 
 	if (em485) {
 		mdelay(port->rs485.delay_rts_after_send);