path: root/debian/patches-rt/0029-serial-imx-Use-port-lock-wrappers.patch

From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 14 Sep 2023 20:43:46 +0206
Subject: [PATCH 029/134] serial: imx: 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/20230914183831.587273-30-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/imx.c |   84 +++++++++++++++++++++++------------------------
 1 file changed, 42 insertions(+), 42 deletions(-)

--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -575,7 +575,7 @@ static void imx_uart_dma_tx_callback(voi
 	unsigned long flags;
 	u32 ucr1;
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 
 	dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
 
@@ -600,7 +600,7 @@ static void imx_uart_dma_tx_callback(voi
 		imx_uart_writel(sport, ucr4, UCR4);
 	}
 
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 }
 
 /* called with port.lock taken and irqs off */
@@ -766,11 +766,11 @@ static irqreturn_t imx_uart_rtsint(int i
 	struct imx_port *sport = dev_id;
 	irqreturn_t ret;
 
-	spin_lock(&sport->port.lock);
+	uart_port_lock(&sport->port);
 
 	ret = __imx_uart_rtsint(irq, dev_id);
 
-	spin_unlock(&sport->port.lock);
+	uart_port_unlock(&sport->port);
 
 	return ret;
 }
@@ -779,9 +779,9 @@ static irqreturn_t imx_uart_txint(int ir
 {
 	struct imx_port *sport = dev_id;
 
-	spin_lock(&sport->port.lock);
+	uart_port_lock(&sport->port);
 	imx_uart_transmit_buffer(sport);
-	spin_unlock(&sport->port.lock);
+	uart_port_unlock(&sport->port);
 	return IRQ_HANDLED;
 }
 
@@ -895,11 +895,11 @@ static irqreturn_t imx_uart_rxint(int ir
 	struct imx_port *sport = dev_id;
 	irqreturn_t ret;
 
-	spin_lock(&sport->port.lock);
+	uart_port_lock(&sport->port);
 
 	ret = __imx_uart_rxint(irq, dev_id);
 
-	spin_unlock(&sport->port.lock);
+	uart_port_unlock(&sport->port);
 
 	return ret;
 }
@@ -962,7 +962,7 @@ static irqreturn_t imx_uart_int(int irq,
 	unsigned int usr1, usr2, ucr1, ucr2, ucr3, ucr4;
 	irqreturn_t ret = IRQ_NONE;
 
-	spin_lock(&sport->port.lock);
+	uart_port_lock(&sport->port);
 
 	usr1 = imx_uart_readl(sport, USR1);
 	usr2 = imx_uart_readl(sport, USR2);
@@ -1032,7 +1032,7 @@ static irqreturn_t imx_uart_int(int irq,
 		ret = IRQ_HANDLED;
 	}
 
-	spin_unlock(&sport->port.lock);
+	uart_port_unlock(&sport->port);
 
 	return ret;
 }
@@ -1115,7 +1115,7 @@ static void imx_uart_break_ctl(struct ua
 	unsigned long flags;
 	u32 ucr1;
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 
 	ucr1 = imx_uart_readl(sport, UCR1) & ~UCR1_SNDBRK;
 
@@ -1124,7 +1124,7 @@ static void imx_uart_break_ctl(struct ua
 
 	imx_uart_writel(sport, ucr1, UCR1);
 
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 }
 
 /*
@@ -1137,9 +1137,9 @@ static void imx_uart_timeout(struct time
 	unsigned long flags;
 
 	if (sport->port.state) {
-		spin_lock_irqsave(&sport->port.lock, flags);
+		uart_port_lock_irqsave(&sport->port, &flags);
 		imx_uart_mctrl_check(sport);
-		spin_unlock_irqrestore(&sport->port.lock, flags);
+		uart_port_unlock_irqrestore(&sport->port, flags);
 
 		mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
 	}
@@ -1169,9 +1169,9 @@ static void imx_uart_dma_rx_callback(voi
 	status = dmaengine_tx_status(chan, sport->rx_cookie, &state);
 
 	if (status == DMA_ERROR) {
-		spin_lock(&sport->port.lock);
+		uart_port_lock(&sport->port);
 		imx_uart_clear_rx_errors(sport);
-		spin_unlock(&sport->port.lock);
+		uart_port_unlock(&sport->port);
 		return;
 	}
 
@@ -1200,9 +1200,9 @@ static void imx_uart_dma_rx_callback(voi
 		r_bytes = rx_ring->head - rx_ring->tail;
 
 		/* If we received something, check for 0xff flood */
-		spin_lock(&sport->port.lock);
+		uart_port_lock(&sport->port);
 		imx_uart_check_flood(sport, imx_uart_readl(sport, USR2));
-		spin_unlock(&sport->port.lock);
+		uart_port_unlock(&sport->port);
 
 		if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ)) {
 
@@ -1460,7 +1460,7 @@ static int imx_uart_startup(struct uart_
 	if (!uart_console(port) && imx_uart_dma_init(sport) == 0)
 		dma_is_inited = 1;
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 
 	/* Reset fifo's and state machines */
 	imx_uart_soft_reset(sport);
@@ -1533,7 +1533,7 @@ static int imx_uart_startup(struct uart_
 
 	imx_uart_disable_loopback_rs485(sport);
 
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 
 	return 0;
 }
@@ -1558,21 +1558,21 @@ static void imx_uart_shutdown(struct uar
 			sport->dma_is_rxing = 0;
 		}
 
-		spin_lock_irqsave(&sport->port.lock, flags);
+		uart_port_lock_irqsave(&sport->port, &flags);
 		imx_uart_stop_tx(port);
 		imx_uart_stop_rx(port);
 		imx_uart_disable_dma(sport);
-		spin_unlock_irqrestore(&sport->port.lock, flags);
+		uart_port_unlock_irqrestore(&sport->port, flags);
 		imx_uart_dma_exit(sport);
 	}
 
 	mctrl_gpio_disable_ms(sport->gpios);
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 	ucr2 = imx_uart_readl(sport, UCR2);
 	ucr2 &= ~(UCR2_TXEN | UCR2_ATEN);
 	imx_uart_writel(sport, ucr2, UCR2);
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 
 	/*
 	 * Stop our timer.
@@ -1583,7 +1583,7 @@ static void imx_uart_shutdown(struct uar
 	 * Disable all interrupts, port and break condition.
 	 */
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 
 	ucr1 = imx_uart_readl(sport, UCR1);
 	ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_RXDMAEN |
@@ -1605,7 +1605,7 @@ static void imx_uart_shutdown(struct uar
 	ucr4 &= ~UCR4_TCEN;
 	imx_uart_writel(sport, ucr4, UCR4);
 
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 
 	clk_disable_unprepare(sport->clk_per);
 	clk_disable_unprepare(sport->clk_ipg);
@@ -1668,7 +1668,7 @@ imx_uart_set_termios(struct uart_port *p
 	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
 	quot = uart_get_divisor(port, baud);
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 
 	/*
 	 * Read current UCR2 and save it for future use, then clear all the bits
@@ -1796,7 +1796,7 @@ imx_uart_set_termios(struct uart_port *p
 	if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
 		imx_uart_enable_ms(&sport->port);
 
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 }
 
 static const char *imx_uart_type(struct uart_port *port)
@@ -1858,7 +1858,7 @@ static int imx_uart_poll_init(struct uar
 
 	imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 
 	/*
 	 * Be careful about the order of enabling bits here. First enable the
@@ -1886,7 +1886,7 @@ static int imx_uart_poll_init(struct uar
 	imx_uart_writel(sport, ucr1 | UCR1_RRDYEN, UCR1);
 	imx_uart_writel(sport, ucr2 | UCR2_ATEN, UCR2);
 
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 
 	return 0;
 }
@@ -2005,9 +2005,9 @@ imx_uart_console_write(struct console *c
 	if (sport->port.sysrq)
 		locked = 0;
 	else if (oops_in_progress)
-		locked = spin_trylock_irqsave(&sport->port.lock, flags);
+		locked = uart_port_trylock_irqsave(&sport->port, &flags);
 	else
-		spin_lock_irqsave(&sport->port.lock, flags);
+		uart_port_lock_irqsave(&sport->port, &flags);
 
 	/*
 	 *	First, save UCR1/2/3 and then disable interrupts
@@ -2035,7 +2035,7 @@ imx_uart_console_write(struct console *c
 	imx_uart_ucrs_restore(sport, &old_ucr);
 
 	if (locked)
-		spin_unlock_irqrestore(&sport->port.lock, flags);
+		uart_port_unlock_irqrestore(&sport->port, flags);
 }
 
 /*
@@ -2193,10 +2193,10 @@ static enum hrtimer_restart imx_trigger_
 	struct imx_port *sport = container_of(t, struct imx_port, trigger_start_tx);
 	unsigned long flags;
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 	if (sport->tx_state == WAIT_AFTER_RTS)
 		imx_uart_start_tx(&sport->port);
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 
 	return HRTIMER_NORESTART;
 }
@@ -2206,10 +2206,10 @@ static enum hrtimer_restart imx_trigger_
 	struct imx_port *sport = container_of(t, struct imx_port, trigger_stop_tx);
 	unsigned long flags;
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 	if (sport->tx_state == WAIT_AFTER_SEND)
 		imx_uart_stop_tx(&sport->port);
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 
 	return HRTIMER_NORESTART;
 }
@@ -2482,9 +2482,9 @@ static void imx_uart_restore_context(str
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 	if (!sport->context_saved) {
-		spin_unlock_irqrestore(&sport->port.lock, flags);
+		uart_port_unlock_irqrestore(&sport->port, flags);
 		return;
 	}
 
@@ -2499,7 +2499,7 @@ static void imx_uart_restore_context(str
 	imx_uart_writel(sport, sport->saved_reg[2], UCR3);
 	imx_uart_writel(sport, sport->saved_reg[3], UCR4);
 	sport->context_saved = false;
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 }
 
 static void imx_uart_save_context(struct imx_port *sport)
@@ -2507,7 +2507,7 @@ static void imx_uart_save_context(struct
 	unsigned long flags;
 
 	/* Save necessary regs */
-	spin_lock_irqsave(&sport->port.lock, flags);
+	uart_port_lock_irqsave(&sport->port, &flags);
 	sport->saved_reg[0] = imx_uart_readl(sport, UCR1);
 	sport->saved_reg[1] = imx_uart_readl(sport, UCR2);
 	sport->saved_reg[2] = imx_uart_readl(sport, UCR3);
@@ -2519,7 +2519,7 @@ static void imx_uart_save_context(struct
 	sport->saved_reg[8] = imx_uart_readl(sport, UBMR);
 	sport->saved_reg[9] = imx_uart_readl(sport, IMX21_UTS);
 	sport->context_saved = true;
-	spin_unlock_irqrestore(&sport->port.lock, flags);
+	uart_port_unlock_irqrestore(&sport->port, flags);
 }
 
 static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)