From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:50 +0206 Subject: [PATCH 033/134] serial: lpc32xx_hs: 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/20230914183831.587273-34-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/lpc32xx_hs.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) --- a/drivers/tty/serial/lpc32xx_hs.c +++ b/drivers/tty/serial/lpc32xx_hs.c @@ -140,15 +140,15 @@ static void lpc32xx_hsuart_console_write 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); uart_console_write(&up->port, s, count, lpc32xx_hsuart_console_putchar); wait_for_xmit_empty(&up->port); if (locked) - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); local_irq_restore(flags); } @@ -298,7 +298,7 @@ static irqreturn_t serial_lpc32xx_interr struct tty_port *tport = &port->state->port; u32 status; - spin_lock(&port->lock); + uart_port_lock(port); /* Read UART status and clear latched interrupts */ status = readl(LPC32XX_HSUART_IIR(port->membase)); @@ -333,7 +333,7 @@ static irqreturn_t serial_lpc32xx_interr __serial_lpc32xx_tx(port); } - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_HANDLED; } @@ -404,14 +404,14 @@ static void serial_lpc32xx_break_ctl(str unsigned long flags; u32 tmp; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); tmp = readl(LPC32XX_HSUART_CTRL(port->membase)); if (break_state != 0) tmp |= LPC32XX_HSU_BREAK; else tmp &= ~LPC32XX_HSU_BREAK; writel(tmp, LPC32XX_HSUART_CTRL(port->membase)); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* port->lock is not held. */ @@ -421,7 +421,7 @@ static int serial_lpc32xx_startup(struct unsigned long flags; u32 tmp; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); __serial_uart_flush(port); @@ -441,7 +441,7 @@ static int serial_lpc32xx_startup(struct lpc32xx_loopback_set(port->mapbase, 0); /* get out of loopback mode */ - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); retval = request_irq(port->irq, serial_lpc32xx_interrupt, 0, MODNAME, port); @@ -458,7 +458,7 @@ static void serial_lpc32xx_shutdown(stru u32 tmp; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); tmp = LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B | LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B; @@ -466,7 +466,7 @@ static void serial_lpc32xx_shutdown(stru lpc32xx_loopback_set(port->mapbase, 1); /* go to loopback mode */ - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); free_irq(port->irq, port); } @@ -491,7 +491,7 @@ static void serial_lpc32xx_set_termios(s quot = __serial_get_clock_div(port->uartclk, baud); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Ignore characters? */ tmp = readl(LPC32XX_HSUART_CTRL(port->membase)); @@ -505,7 +505,7 @@ static void serial_lpc32xx_set_termios(s uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); /* Don't rewrite B0 */ if (tty_termios_baud_rate(termios))