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From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 14 Sep 2023 20:44:05 +0206
Subject: [PATCH 048/134] serial: pxa: 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/20230914183831.587273-49-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/pxa.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
--- a/drivers/tty/serial/pxa.c
+++ b/drivers/tty/serial/pxa.c
@@ -225,14 +225,14 @@ static inline irqreturn_t serial_pxa_irq
iir = serial_in(up, UART_IIR);
if (iir & UART_IIR_NO_INT)
return IRQ_NONE;
- spin_lock(&up->port.lock);
+ uart_port_lock(&up->port);
lsr = serial_in(up, UART_LSR);
if (lsr & UART_LSR_DR)
receive_chars(up, &lsr);
check_modem_status(up);
if (lsr & UART_LSR_THRE)
transmit_chars(up);
- spin_unlock(&up->port.lock);
+ uart_port_unlock(&up->port);
return IRQ_HANDLED;
}
@@ -242,9 +242,9 @@ static unsigned int serial_pxa_tx_empty(
unsigned long flags;
unsigned int ret;
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
return ret;
}
@@ -295,13 +295,13 @@ static void serial_pxa_break_ctl(struct
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned long flags;
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
if (break_state == -1)
up->lcr |= UART_LCR_SBC;
else
up->lcr &= ~UART_LCR_SBC;
serial_out(up, UART_LCR, up->lcr);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
}
static int serial_pxa_startup(struct uart_port *port)
@@ -346,10 +346,10 @@ static int serial_pxa_startup(struct uar
*/
serial_out(up, UART_LCR, UART_LCR_WLEN8);
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
up->port.mctrl |= TIOCM_OUT2;
serial_pxa_set_mctrl(&up->port, up->port.mctrl);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
/*
* Finally, enable interrupts. Note: Modem status interrupts
@@ -383,10 +383,10 @@ static void serial_pxa_shutdown(struct u
up->ier = 0;
serial_out(up, UART_IER, 0);
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
up->port.mctrl &= ~TIOCM_OUT2;
serial_pxa_set_mctrl(&up->port, up->port.mctrl);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
/*
* Disable break condition and FIFOs
@@ -434,7 +434,7 @@ serial_pxa_set_termios(struct uart_port
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
/*
* Ensure the port will be enabled.
@@ -504,7 +504,7 @@ serial_pxa_set_termios(struct uart_port
up->lcr = cval; /* Save LCR */
serial_pxa_set_mctrl(&up->port, up->port.mctrl);
serial_out(up, UART_FCR, fcr);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
}
static void
@@ -608,9 +608,9 @@ serial_pxa_console_write(struct console
if (up->port.sysrq)
locked = 0;
else if (oops_in_progress)
- locked = spin_trylock(&up->port.lock);
+ locked = uart_port_trylock(&up->port);
else
- spin_lock(&up->port.lock);
+ uart_port_lock(&up->port);
/*
* First save the IER then disable the interrupts
@@ -628,7 +628,7 @@ serial_pxa_console_write(struct console
serial_out(up, UART_IER, ier);
if (locked)
- spin_unlock(&up->port.lock);
+ uart_port_unlock(&up->port);
local_irq_restore(flags);
clk_disable(up->clk);
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