From 8777b7deb3069b2747696a2971979eaf11d0d42c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:36 +0206 Subject: [PATCH 045/196] serial: ar933x: Use port lock wrappers 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 Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-20-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/ar933x_uart.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c index 924c1a89347c..ffd234673177 100644 --- a/drivers/tty/serial/ar933x_uart.c +++ b/drivers/tty/serial/ar933x_uart.c @@ -133,9 +133,9 @@ static unsigned int ar933x_uart_tx_empty(struct uart_port *port) unsigned long flags; unsigned int rdata; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT; } @@ -220,14 +220,14 @@ static void ar933x_uart_break_ctl(struct uart_port *port, int break_state) container_of(port, struct ar933x_uart_port, port); unsigned long flags; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); if (break_state == -1) ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, AR933X_UART_CS_TX_BREAK); else ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, AR933X_UART_CS_TX_BREAK); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } /* @@ -318,7 +318,7 @@ static void ar933x_uart_set_termios(struct uart_port *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); /* disable the UART */ ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, @@ -352,7 +352,7 @@ static void ar933x_uart_set_termios(struct uart_port *port, AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S, AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); if (tty_termios_baud_rate(new)) tty_termios_encode_baud_rate(new, baud, baud); @@ -450,7 +450,7 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id) if ((status & AR933X_UART_CS_HOST_INT) == 0) return IRQ_NONE; - spin_lock(&up->port.lock); + uart_port_lock(&up->port); status = ar933x_uart_read(up, AR933X_UART_INT_REG); status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG); @@ -468,7 +468,7 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id) ar933x_uart_tx_chars(up); } - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); return IRQ_HANDLED; } @@ -485,7 +485,7 @@ static int ar933x_uart_startup(struct uart_port *port) if (ret) return ret; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); /* Enable HOST interrupts */ ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, @@ -498,7 +498,7 @@ static int ar933x_uart_startup(struct uart_port *port) /* Enable RX interrupts */ ar933x_uart_start_rx_interrupt(up); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return 0; } @@ -632,9 +632,9 @@ static void ar933x_uart_console_write(struct console *co, const char *s, 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 @@ -654,7 +654,7 @@ static void ar933x_uart_console_write(struct console *co, const char *s, ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS); if (locked) - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); local_irq_restore(flags); } -- 2.43.2