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From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 14 Sep 2023 20:43:47 +0206
Subject: [PATCH 030/134] serial: ip22zilog: 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/20230914183831.587273-31-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/ip22zilog.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
--- a/drivers/tty/serial/ip22zilog.c
+++ b/drivers/tty/serial/ip22zilog.c
@@ -432,7 +432,7 @@ static irqreturn_t ip22zilog_interrupt(i
unsigned char r3;
bool push = false;
- spin_lock(&up->port.lock);
+ uart_port_lock(&up->port);
r3 = read_zsreg(channel, R3);
/* Channel A */
@@ -448,7 +448,7 @@ static irqreturn_t ip22zilog_interrupt(i
if (r3 & CHATxIP)
ip22zilog_transmit_chars(up, channel);
}
- spin_unlock(&up->port.lock);
+ uart_port_unlock(&up->port);
if (push)
tty_flip_buffer_push(&up->port.state->port);
@@ -458,7 +458,7 @@ static irqreturn_t ip22zilog_interrupt(i
channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
push = false;
- spin_lock(&up->port.lock);
+ uart_port_lock(&up->port);
if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
writeb(RES_H_IUS, &channel->control);
ZSDELAY();
@@ -471,7 +471,7 @@ static irqreturn_t ip22zilog_interrupt(i
if (r3 & CHBTxIP)
ip22zilog_transmit_chars(up, channel);
}
- spin_unlock(&up->port.lock);
+ uart_port_unlock(&up->port);
if (push)
tty_flip_buffer_push(&up->port.state->port);
@@ -504,11 +504,11 @@ static unsigned int ip22zilog_tx_empty(s
unsigned char status;
unsigned int ret;
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, &flags);
status = ip22zilog_read_channel_status(port);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
if (status & Tx_BUF_EMP)
ret = TIOCSER_TEMT;
@@ -664,7 +664,7 @@ static void ip22zilog_break_ctl(struct u
else
clear_bits |= SND_BRK;
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, &flags);
new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
if (new_reg != up->curregs[R5]) {
@@ -674,7 +674,7 @@ static void ip22zilog_break_ctl(struct u
write_zsreg(channel, R5, up->curregs[R5]);
}
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
}
static void __ip22zilog_reset(struct uart_ip22zilog_port *up)
@@ -735,9 +735,9 @@ static int ip22zilog_startup(struct uart
if (ZS_IS_CONS(up))
return 0;
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, &flags);
__ip22zilog_startup(up);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
return 0;
}
@@ -775,7 +775,7 @@ static void ip22zilog_shutdown(struct ua
if (ZS_IS_CONS(up))
return;
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, &flags);
channel = ZILOG_CHANNEL_FROM_PORT(port);
@@ -788,7 +788,7 @@ static void ip22zilog_shutdown(struct ua
up->curregs[R5] &= ~SND_BRK;
ip22zilog_maybe_update_regs(up, channel);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
}
/* Shared by TTY driver and serial console setup. The port lock is held
@@ -880,7 +880,7 @@ ip22zilog_set_termios(struct uart_port *
baud = uart_get_baud_rate(port, termios, old, 1200, 76800);
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
@@ -894,7 +894,7 @@ ip22zilog_set_termios(struct uart_port *
ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));
uart_update_timeout(port, termios->c_cflag, baud);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
}
static const char *ip22zilog_type(struct uart_port *port)
@@ -1016,10 +1016,10 @@ ip22zilog_console_write(struct console *
struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
unsigned long flags;
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
uart_console_write(&up->port, s, count, ip22zilog_put_char);
udelay(2);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
}
static int __init ip22zilog_console_setup(struct console *con, char *options)
@@ -1034,13 +1034,13 @@ static int __init ip22zilog_console_setu
printk(KERN_INFO "Console: ttyS%d (IP22-Zilog)\n", con->index);
- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, &flags);
up->curregs[R15] |= BRKIE;
__ip22zilog_startup(up);
- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
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