From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:44:16 +0206 Subject: [PATCH 059/134] serial: txx9: 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 Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-60-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/serial_txx9.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) --- a/drivers/tty/serial/serial_txx9.c +++ b/drivers/tty/serial/serial_txx9.c @@ -335,13 +335,13 @@ static irqreturn_t serial_txx9_interrupt unsigned int status; while (1) { - spin_lock(&up->lock); + uart_port_lock(up); status = sio_in(up, TXX9_SIDISR); if (!(sio_in(up, TXX9_SIDICR) & TXX9_SIDICR_TIE)) status &= ~TXX9_SIDISR_TDIS; if (!(status & (TXX9_SIDISR_TDIS | TXX9_SIDISR_RDIS | TXX9_SIDISR_TOUT))) { - spin_unlock(&up->lock); + uart_port_unlock(up); break; } @@ -353,7 +353,7 @@ static irqreturn_t serial_txx9_interrupt sio_mask(up, TXX9_SIDISR, TXX9_SIDISR_TDIS | TXX9_SIDISR_RDIS | TXX9_SIDISR_TOUT); - spin_unlock(&up->lock); + uart_port_unlock(up); if (pass_counter++ > PASS_LIMIT) break; @@ -367,9 +367,9 @@ static unsigned int serial_txx9_tx_empty unsigned long flags; unsigned int ret; - spin_lock_irqsave(&up->lock, flags); + uart_port_lock_irqsave(up, &flags); ret = (sio_in(up, TXX9_SICISR) & TXX9_SICISR_TXALS) ? TIOCSER_TEMT : 0; - spin_unlock_irqrestore(&up->lock, flags); + uart_port_unlock_irqrestore(up, flags); return ret; } @@ -399,12 +399,12 @@ static void serial_txx9_break_ctl(struct { unsigned long flags; - spin_lock_irqsave(&up->lock, flags); + uart_port_lock_irqsave(up, &flags); if (break_state == -1) sio_set(up, TXX9_SIFLCR, TXX9_SIFLCR_TBRK); else sio_mask(up, TXX9_SIFLCR, TXX9_SIFLCR_TBRK); - spin_unlock_irqrestore(&up->lock, flags); + uart_port_unlock_irqrestore(up, flags); } #if defined(CONFIG_SERIAL_TXX9_CONSOLE) || defined(CONFIG_CONSOLE_POLL) @@ -517,9 +517,9 @@ static int serial_txx9_startup(struct ua /* * Now, initialize the UART */ - spin_lock_irqsave(&up->lock, flags); + uart_port_lock_irqsave(up, &flags); serial_txx9_set_mctrl(up, up->mctrl); - spin_unlock_irqrestore(&up->lock, flags); + uart_port_unlock_irqrestore(up, flags); /* Enable RX/TX */ sio_mask(up, TXX9_SIFLCR, TXX9_SIFLCR_RSDE | TXX9_SIFLCR_TSDE); @@ -541,9 +541,9 @@ static void serial_txx9_shutdown(struct */ sio_out(up, TXX9_SIDICR, 0); /* disable all intrs */ - spin_lock_irqsave(&up->lock, flags); + uart_port_lock_irqsave(up, &flags); serial_txx9_set_mctrl(up, up->mctrl); - spin_unlock_irqrestore(&up->lock, flags); + uart_port_unlock_irqrestore(up, flags); /* * Disable break condition @@ -625,7 +625,7 @@ serial_txx9_set_termios(struct uart_port * Ok, we're now changing the port state. Do it with * interrupts disabled. */ - spin_lock_irqsave(&up->lock, flags); + uart_port_lock_irqsave(up, &flags); /* * Update the per-port timeout. @@ -676,7 +676,7 @@ serial_txx9_set_termios(struct uart_port sio_out(up, TXX9_SIFCR, fcr); serial_txx9_set_mctrl(up, up->mctrl); - spin_unlock_irqrestore(&up->lock, flags); + uart_port_unlock_irqrestore(up, flags); } static void