From 174bb9e1e1fa3d4ef2c46054621435dbf7a7dc66 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:31 +0206 Subject: [PATCH 041/195] serial: altera_jtaguart: 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/20230914183831.587273-15-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/altera_jtaguart.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c index 5fab4c978891..7090b251dd4d 100644 --- a/drivers/tty/serial/altera_jtaguart.c +++ b/drivers/tty/serial/altera_jtaguart.c @@ -147,14 +147,14 @@ static irqreturn_t altera_jtaguart_interrupt(int irq, void *data) isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> ALTERA_JTAGUART_CONTROL_RI_OFF) & port->read_status_mask; - spin_lock(&port->lock); + uart_port_lock(port); if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) altera_jtaguart_rx_chars(port); if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) altera_jtaguart_tx_chars(port); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_RETVAL(isr); } @@ -180,14 +180,14 @@ static int altera_jtaguart_startup(struct uart_port *port) return ret; } - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Enable RX interrupts now */ port->read_status_mask = ALTERA_JTAGUART_CONTROL_RE_MSK; writel(port->read_status_mask, port->membase + ALTERA_JTAGUART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return 0; } @@ -196,14 +196,14 @@ static void altera_jtaguart_shutdown(struct uart_port *port) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable all interrupts now */ port->read_status_mask = 0; writel(port->read_status_mask, port->membase + ALTERA_JTAGUART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); free_irq(port->irq, port); } @@ -264,33 +264,33 @@ static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c unsigned long flags; u32 status; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (!altera_jtaguart_tx_space(port, &status)) { - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { return; /* no connection activity */ } cpu_relax(); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); } writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } #else static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (!altera_jtaguart_tx_space(port, NULL)) { - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); cpu_relax(); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); } writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } #endif -- 2.43.0