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-rw-r--r--debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch151
1 files changed, 151 insertions, 0 deletions
diff --git a/debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch b/debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..55ae035b80
--- /dev/null
+++ b/debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch
@@ -0,0 +1,151 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:43:22 +0206
+Subject: [PATCH 005/134] serial: 8250_bcm7271: 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/20230914183831.587273-6-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/8250/8250_bcm7271.c | 28 ++++++++++++++--------------
+ 1 file changed, 14 insertions(+), 14 deletions(-)
+
+--- a/drivers/tty/serial/8250/8250_bcm7271.c
++++ b/drivers/tty/serial/8250/8250_bcm7271.c
+@@ -567,7 +567,7 @@ static irqreturn_t brcmuart_isr(int irq,
+ if (interrupts == 0)
+ return IRQ_NONE;
+
+- spin_lock_irqsave(&up->lock, flags);
++ uart_port_lock_irqsave(up, &flags);
+
+ /* Clear all interrupts */
+ udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, interrupts);
+@@ -581,7 +581,7 @@ static irqreturn_t brcmuart_isr(int irq,
+ if ((rval | tval) == 0)
+ dev_warn(dev, "Spurious interrupt: 0x%x\n", interrupts);
+
+- spin_unlock_irqrestore(&up->lock, flags);
++ uart_port_unlock_irqrestore(up, flags);
+ return IRQ_HANDLED;
+ }
+
+@@ -608,10 +608,10 @@ static int brcmuart_startup(struct uart_
+ *
+ * Synchronize UART_IER access against the console.
+ */
+- spin_lock_irq(&port->lock);
++ uart_port_lock_irq(port);
+ up->ier &= ~UART_IER_RDI;
+ serial_port_out(port, UART_IER, up->ier);
+- spin_unlock_irq(&port->lock);
++ uart_port_unlock_irq(port);
+
+ priv->tx_running = false;
+ priv->dma.rx_dma = NULL;
+@@ -629,7 +629,7 @@ static void brcmuart_shutdown(struct uar
+ struct brcmuart_priv *priv = up->port.private_data;
+ unsigned long flags;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ priv->shutdown = true;
+ if (priv->dma_enabled) {
+ stop_rx_dma(up);
+@@ -645,7 +645,7 @@ static void brcmuart_shutdown(struct uar
+ */
+ up->dma = NULL;
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ serial8250_do_shutdown(port);
+ }
+
+@@ -788,7 +788,7 @@ static int brcmuart_handle_irq(struct ua
+ * interrupt but there is no data ready.
+ */
+ if (((iir & UART_IIR_ID) == UART_IIR_RX_TIMEOUT) && !(priv->shutdown)) {
+- spin_lock_irqsave(&p->lock, flags);
++ uart_port_lock_irqsave(p, &flags);
+ status = serial_port_in(p, UART_LSR);
+ if ((status & UART_LSR_DR) == 0) {
+
+@@ -813,7 +813,7 @@ static int brcmuart_handle_irq(struct ua
+
+ handled = 1;
+ }
+- spin_unlock_irqrestore(&p->lock, flags);
++ uart_port_unlock_irqrestore(p, flags);
+ if (handled)
+ return 1;
+ }
+@@ -831,7 +831,7 @@ static enum hrtimer_restart brcmuart_hrt
+ if (priv->shutdown)
+ return HRTIMER_NORESTART;
+
+- spin_lock_irqsave(&p->lock, flags);
++ uart_port_lock_irqsave(p, &flags);
+ status = serial_port_in(p, UART_LSR);
+
+ /*
+@@ -855,7 +855,7 @@ static enum hrtimer_restart brcmuart_hrt
+ status |= UART_MCR_RTS;
+ serial_port_out(p, UART_MCR, status);
+ }
+- spin_unlock_irqrestore(&p->lock, flags);
++ uart_port_unlock_irqrestore(p, flags);
+ return HRTIMER_NORESTART;
+ }
+
+@@ -1154,10 +1154,10 @@ static int __maybe_unused brcmuart_suspe
+ * This will prevent resume from enabling RTS before the
+ * baud rate has been restored.
+ */
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ priv->saved_mctrl = port->mctrl;
+ port->mctrl &= ~TIOCM_RTS;
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ serial8250_suspend_port(priv->line);
+ clk_disable_unprepare(priv->baud_mux_clk);
+@@ -1196,10 +1196,10 @@ static int __maybe_unused brcmuart_resum
+
+ if (priv->saved_mctrl & TIOCM_RTS) {
+ /* Restore RTS */
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ port->mctrl |= TIOCM_RTS;
+ port->ops->set_mctrl(port, port->mctrl);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ return 0;