From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 14 Sep 2023 20:44:31 +0206
Subject: [PATCH 074/134] serial: xilinx_uartps: Use port lock wrappers
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz

When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.

So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.

All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.

To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.

Converted with coccinelle. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20230914183831.587273-75-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/tty/serial/xilinx_uartps.c |   56 ++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -346,7 +346,7 @@ static irqreturn_t cdns_uart_isr(int irq
 	struct uart_port *port = (struct uart_port *)dev_id;
 	unsigned int isrstatus;
 
-	spin_lock(&port->lock);
+	uart_port_lock(port);
 
 	/* Read the interrupt status register to determine which
 	 * interrupt(s) is/are active and clear them.
@@ -369,7 +369,7 @@ static irqreturn_t cdns_uart_isr(int irq
 	    !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS))
 		cdns_uart_handle_rx(dev_id, isrstatus);
 
-	spin_unlock(&port->lock);
+	uart_port_unlock(port);
 	return IRQ_HANDLED;
 }
 
@@ -506,14 +506,14 @@ static int cdns_uart_clk_notifier_cb(str
 			return NOTIFY_BAD;
 		}
 
-		spin_lock_irqsave(&cdns_uart->port->lock, flags);
+		uart_port_lock_irqsave(cdns_uart->port, &flags);
 
 		/* Disable the TX and RX to set baud rate */
 		ctrl_reg = readl(port->membase + CDNS_UART_CR);
 		ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS;
 		writel(ctrl_reg, port->membase + CDNS_UART_CR);
 
-		spin_unlock_irqrestore(&cdns_uart->port->lock, flags);
+		uart_port_unlock_irqrestore(cdns_uart->port, flags);
 
 		return NOTIFY_OK;
 	}
@@ -523,7 +523,7 @@ static int cdns_uart_clk_notifier_cb(str
 		 * frequency.
 		 */
 
-		spin_lock_irqsave(&cdns_uart->port->lock, flags);
+		uart_port_lock_irqsave(cdns_uart->port, &flags);
 
 		locked = 1;
 		port->uartclk = ndata->new_rate;
@@ -533,7 +533,7 @@ static int cdns_uart_clk_notifier_cb(str
 		fallthrough;
 	case ABORT_RATE_CHANGE:
 		if (!locked)
-			spin_lock_irqsave(&cdns_uart->port->lock, flags);
+			uart_port_lock_irqsave(cdns_uart->port, &flags);
 
 		/* Set TX/RX Reset */
 		ctrl_reg = readl(port->membase + CDNS_UART_CR);
@@ -555,7 +555,7 @@ static int cdns_uart_clk_notifier_cb(str
 		ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
 		writel(ctrl_reg, port->membase + CDNS_UART_CR);
 
-		spin_unlock_irqrestore(&cdns_uart->port->lock, flags);
+		uart_port_unlock_irqrestore(cdns_uart->port, flags);
 
 		return NOTIFY_OK;
 	default:
@@ -652,7 +652,7 @@ static void cdns_uart_break_ctl(struct u
 	unsigned int status;
 	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	status = readl(port->membase + CDNS_UART_CR);
 
@@ -664,7 +664,7 @@ static void cdns_uart_break_ctl(struct u
 			writel(CDNS_UART_CR_STOPBRK | status,
 					port->membase + CDNS_UART_CR);
 	}
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 }
 
 /**
@@ -683,7 +683,7 @@ static void cdns_uart_set_termios(struct
 	unsigned long flags;
 	unsigned int ctrl_reg, mode_reg;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	/* Disable the TX and RX to set baud rate */
 	ctrl_reg = readl(port->membase + CDNS_UART_CR);
@@ -794,7 +794,7 @@ static void cdns_uart_set_termios(struct
 		cval &= ~CDNS_UART_MODEMCR_FCM;
 	writel(cval, port->membase + CDNS_UART_MODEMCR);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 }
 
 /**
@@ -813,7 +813,7 @@ static int cdns_uart_startup(struct uart
 
 	is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	/* Disable the TX and RX */
 	writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
@@ -861,7 +861,7 @@ static int cdns_uart_startup(struct uart
 	writel(readl(port->membase + CDNS_UART_ISR),
 			port->membase + CDNS_UART_ISR);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 
 	ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port);
 	if (ret) {
@@ -889,7 +889,7 @@ static void cdns_uart_shutdown(struct ua
 	int status;
 	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	/* Disable interrupts */
 	status = readl(port->membase + CDNS_UART_IMR);
@@ -900,7 +900,7 @@ static void cdns_uart_shutdown(struct ua
 	writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
 			port->membase + CDNS_UART_CR);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 
 	free_irq(port->irq, port);
 }
@@ -1050,7 +1050,7 @@ static int cdns_uart_poll_get_char(struc
 	int c;
 	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	/* Check if FIFO is empty */
 	if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)
@@ -1058,7 +1058,7 @@ static int cdns_uart_poll_get_char(struc
 	else /* Read a character */
 		c = (unsigned char) readl(port->membase + CDNS_UART_FIFO);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 
 	return c;
 }
@@ -1067,7 +1067,7 @@ static void cdns_uart_poll_put_char(stru
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	/* Wait until FIFO is empty */
 	while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
@@ -1080,7 +1080,7 @@ static void cdns_uart_poll_put_char(stru
 	while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
 		cpu_relax();
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 }
 #endif
 
@@ -1232,9 +1232,9 @@ static void cdns_uart_console_write(stru
 	if (port->sysrq)
 		locked = 0;
 	else if (oops_in_progress)
-		locked = spin_trylock_irqsave(&port->lock, flags);
+		locked = uart_port_trylock_irqsave(port, &flags);
 	else
-		spin_lock_irqsave(&port->lock, flags);
+		uart_port_lock_irqsave(port, &flags);
 
 	/* save and disable interrupt */
 	imr = readl(port->membase + CDNS_UART_IMR);
@@ -1257,7 +1257,7 @@ static void cdns_uart_console_write(stru
 	writel(imr, port->membase + CDNS_UART_IER);
 
 	if (locked)
-		spin_unlock_irqrestore(&port->lock, flags);
+		uart_port_unlock_irqrestore(port, flags);
 }
 
 /**
@@ -1325,7 +1325,7 @@ static int cdns_uart_suspend(struct devi
 	if (console_suspend_enabled && uart_console(port) && may_wake) {
 		unsigned long flags;
 
-		spin_lock_irqsave(&port->lock, flags);
+		uart_port_lock_irqsave(port, &flags);
 		/* Empty the receive FIFO 1st before making changes */
 		while (!(readl(port->membase + CDNS_UART_SR) &
 					CDNS_UART_SR_RXEMPTY))
@@ -1334,7 +1334,7 @@ static int cdns_uart_suspend(struct devi
 		writel(1, port->membase + CDNS_UART_RXWM);
 		/* disable RX timeout interrups */
 		writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR);
-		spin_unlock_irqrestore(&port->lock, flags);
+		uart_port_unlock_irqrestore(port, flags);
 	}
 
 	/*
@@ -1372,7 +1372,7 @@ static int cdns_uart_resume(struct devic
 			return ret;
 		}
 
-		spin_lock_irqsave(&port->lock, flags);
+		uart_port_lock_irqsave(port, &flags);
 
 		/* Set TX/RX Reset */
 		ctrl_reg = readl(port->membase + CDNS_UART_CR);
@@ -1392,14 +1392,14 @@ static int cdns_uart_resume(struct devic
 
 		clk_disable(cdns_uart->uartclk);
 		clk_disable(cdns_uart->pclk);
-		spin_unlock_irqrestore(&port->lock, flags);
+		uart_port_unlock_irqrestore(port, flags);
 	} else {
-		spin_lock_irqsave(&port->lock, flags);
+		uart_port_lock_irqsave(port, &flags);
 		/* restore original rx trigger level */
 		writel(rx_trigger_level, port->membase + CDNS_UART_RXWM);
 		/* enable RX timeout interrupt */
 		writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER);
-		spin_unlock_irqrestore(&port->lock, flags);
+		uart_port_unlock_irqrestore(port, flags);
 	}
 
 	return uart_resume_port(cdns_uart->cdns_uart_driver, port);
