From 9ab5733ab07134629faf9863da976517fefa5d2a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:43 +0206 Subject: [PATCH 052/196] serial: linflexuart: 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/20230914183831.587273-27-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/fsl_linflexuart.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/drivers/tty/serial/fsl_linflexuart.c b/drivers/tty/serial/fsl_linflexuart.c index 249cb380c3c6..7fa809a405e8 100644 --- a/drivers/tty/serial/fsl_linflexuart.c +++ b/drivers/tty/serial/fsl_linflexuart.c @@ -203,7 +203,7 @@ static irqreturn_t linflex_txint(int irq, void *dev_id) struct circ_buf *xmit = &sport->state->xmit; unsigned long flags; - spin_lock_irqsave(&sport->lock, flags); + uart_port_lock_irqsave(sport, &flags); if (sport->x_char) { linflex_put_char(sport, sport->x_char); @@ -217,7 +217,7 @@ static irqreturn_t linflex_txint(int irq, void *dev_id) linflex_transmit_buffer(sport); out: - spin_unlock_irqrestore(&sport->lock, flags); + uart_port_unlock_irqrestore(sport, flags); return IRQ_HANDLED; } @@ -230,7 +230,7 @@ static irqreturn_t linflex_rxint(int irq, void *dev_id) unsigned char rx; bool brk; - spin_lock_irqsave(&sport->lock, flags); + uart_port_lock_irqsave(sport, &flags); status = readl(sport->membase + UARTSR); while (status & LINFLEXD_UARTSR_RMB) { @@ -266,7 +266,7 @@ static irqreturn_t linflex_rxint(int irq, void *dev_id) } } - spin_unlock_irqrestore(&sport->lock, flags); + uart_port_unlock_irqrestore(sport, flags); tty_flip_buffer_push(port); @@ -369,11 +369,11 @@ static int linflex_startup(struct uart_port *port) int ret = 0; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); linflex_setup_watermark(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); ret = devm_request_irq(port->dev, port->irq, linflex_int, 0, DRIVER_NAME, port); @@ -386,14 +386,14 @@ static void linflex_shutdown(struct uart_port *port) unsigned long ier; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* disable interrupts */ ier = readl(port->membase + LINIER); ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE); writel(ier, port->membase + LINIER); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); devm_free_irq(port->dev, port->irq, port); } @@ -474,7 +474,7 @@ linflex_set_termios(struct uart_port *port, struct ktermios *termios, cr &= ~LINFLEXD_UARTCR_PCE; } - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); port->read_status_mask = 0; @@ -507,7 +507,7 @@ linflex_set_termios(struct uart_port *port, struct ktermios *termios, writel(cr1, port->membase + LINCR1); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *linflex_type(struct uart_port *port) @@ -646,14 +646,14 @@ linflex_console_write(struct console *co, const char *s, unsigned int count) if (sport->sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock_irqsave(&sport->lock, flags); + locked = uart_port_trylock_irqsave(sport, &flags); else - spin_lock_irqsave(&sport->lock, flags); + uart_port_lock_irqsave(sport, &flags); linflex_string_write(sport, s, count); if (locked) - spin_unlock_irqrestore(&sport->lock, flags); + uart_port_unlock_irqrestore(sport, flags); } /* -- 2.43.2