From 660c1ea0b415a9d983dd27e8195283b3f3f92466 Mon Sep 17 00:00:00 2001
From: "Jayachandran C." <jchandra@FreeBSD.org>
Date: Sat, 17 Dec 2016 18:04:59 +0000
Subject: [PATCH] Simplify interrupt mask programming in pl011 uart

Remove unused fields from uart_pl011_softc. Add an interrupt mask
field to the softc and use it to set the interrupt mask register.

There should be no functional change introduced here except in the
grab and ungrab functions. In these functions, we now disable and
enable all interrupts rather than just the receive interrupt.
---
 sys/dev/uart/uart_dev_pl011.c | 45 ++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/sys/dev/uart/uart_dev_pl011.c b/sys/dev/uart/uart_dev_pl011.c
index a7fe24a9aec..bf9a4644b2b 100644
--- a/sys/dev/uart/uart_dev_pl011.c
+++ b/sys/dev/uart/uart_dev_pl011.c
@@ -238,13 +238,8 @@ uart_pl011_getc(struct uart_bas *bas, struct mtx *hwmtx)
  * High-level UART interface.
  */
 struct uart_pl011_softc {
-	struct uart_softc base;
-	uint8_t		fcr;
-	uint8_t		ier;
-	uint8_t		mcr;
-
-	uint8_t		ier_mask;
-	uint8_t		ier_rxbits;
+	struct uart_softc	base;
+	uint16_t		imsc; /* Interrupt mask */
 };
 
 static int uart_pl011_bus_attach(struct uart_softc *);
@@ -309,14 +304,15 @@ UART_ACPI_CLASS_AND_DEVICE(acpi_compat_data);
 static int
 uart_pl011_bus_attach(struct uart_softc *sc)
 {
+	struct uart_pl011_softc *psc;
 	struct uart_bas *bas;
-	int reg;
 
+	psc = (struct uart_pl011_softc *)sc; 
 	bas = &sc->sc_bas;
 
 	/* Enable interrupts */
-	reg = (UART_RXREADY | RIS_RTIM | UART_TXEMPTY);
-	__uart_setreg(bas, UART_IMSC, reg);
+	psc->imsc = (UART_RXREADY | RIS_RTIM | UART_TXEMPTY);
+	__uart_setreg(bas, UART_IMSC, psc->imsc);
 
 	/* Clear interrupts */
 	__uart_setreg(bas, UART_ICR, IMSC_MASK_ALL);
@@ -372,12 +368,14 @@ uart_pl011_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
 static int
 uart_pl011_bus_ipend(struct uart_softc *sc)
 {
+	struct uart_pl011_softc *psc;
 	struct uart_bas *bas;
 	uint32_t ints;
 	int ipend;
-	int reg;
 
+	psc = (struct uart_pl011_softc *)sc; 
 	bas = &sc->sc_bas;
+
 	uart_lock(sc->sc_hwmtx);
 	ints = __uart_getreg(bas, UART_MIS);
 	ipend = 0;
@@ -393,9 +391,7 @@ uart_pl011_bus_ipend(struct uart_softc *sc)
 			ipend |= SER_INT_TXIDLE;
 
 		/* Disable TX interrupt */
-		reg = __uart_getreg(bas, UART_IMSC);
-		reg &= ~(UART_TXEMPTY);
-		__uart_setreg(bas, UART_IMSC, reg);
+		__uart_setreg(bas, UART_IMSC, psc->imsc & ~UART_TXEMPTY);
 	}
 
 	uart_unlock(sc->sc_hwmtx);
@@ -472,10 +468,11 @@ uart_pl011_bus_setsig(struct uart_softc *sc, int sig)
 static int
 uart_pl011_bus_transmit(struct uart_softc *sc)
 {
+	struct uart_pl011_softc *psc;
 	struct uart_bas *bas;
-	int reg;
 	int i;
 
+	psc = (struct uart_pl011_softc *)sc; 
 	bas = &sc->sc_bas;
 	uart_lock(sc->sc_hwmtx);
 
@@ -489,9 +486,7 @@ uart_pl011_bus_transmit(struct uart_softc *sc)
 		sc->sc_txbusy = 1;
 
 		/* Enable TX interrupt */
-		reg = __uart_getreg(bas, UART_IMSC);
-		reg |= (UART_TXEMPTY);
-		__uart_setreg(bas, UART_IMSC, reg);
+		__uart_setreg(bas, UART_IMSC, psc->imsc);
 	}
 
 	uart_unlock(sc->sc_hwmtx);
@@ -506,23 +501,29 @@ uart_pl011_bus_transmit(struct uart_softc *sc)
 static void
 uart_pl011_bus_grab(struct uart_softc *sc)
 {
+	struct uart_pl011_softc *psc;
 	struct uart_bas *bas;
 
+	psc = (struct uart_pl011_softc *)sc; 
 	bas = &sc->sc_bas;
+
+	/* Disable interrupts on switch to polling */
 	uart_lock(sc->sc_hwmtx);
-	__uart_setreg(bas, UART_IMSC, 	/* Switch to RX polling while grabbed */
-	    ~UART_RXREADY & __uart_getreg(bas, UART_IMSC));
+	__uart_setreg(bas, UART_IMSC, psc->imsc & ~IMSC_MASK_ALL);
 	uart_unlock(sc->sc_hwmtx);
 }
 
 static void
 uart_pl011_bus_ungrab(struct uart_softc *sc)
 {
+	struct uart_pl011_softc *psc;
 	struct uart_bas *bas;
 
+	psc = (struct uart_pl011_softc *) sc; 
 	bas = &sc->sc_bas;
+
+	/* Switch to using interrupts while not grabbed */
 	uart_lock(sc->sc_hwmtx);
-	__uart_setreg(bas, UART_IMSC,	/* Switch to RX interrupts while not grabbed */
-	    UART_RXREADY | __uart_getreg(bas, UART_IMSC));
+	__uart_setreg(bas, UART_IMSC, psc->imsc);
 	uart_unlock(sc->sc_hwmtx);
 }