From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:44:31 +0206 Subject: [PATCH 074/134] serial: xilinx_uartps: 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/20230914183831.587273-75-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/xilinx_uartps.c | 56 ++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 28 deletions(-) --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -346,7 +346,7 @@ static irqreturn_t cdns_uart_isr(int irq struct uart_port *port = (struct uart_port *)dev_id; unsigned int isrstatus; - spin_lock(&port->lock); + uart_port_lock(port); /* Read the interrupt status register to determine which * interrupt(s) is/are active and clear them. @@ -369,7 +369,7 @@ static irqreturn_t cdns_uart_isr(int irq !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS)) cdns_uart_handle_rx(dev_id, isrstatus); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_HANDLED; } @@ -506,14 +506,14 @@ static int cdns_uart_clk_notifier_cb(str return NOTIFY_BAD; } - spin_lock_irqsave(&cdns_uart->port->lock, flags); + uart_port_lock_irqsave(cdns_uart->port, &flags); /* Disable the TX and RX to set baud rate */ ctrl_reg = readl(port->membase + CDNS_UART_CR); ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; writel(ctrl_reg, port->membase + CDNS_UART_CR); - spin_unlock_irqrestore(&cdns_uart->port->lock, flags); + uart_port_unlock_irqrestore(cdns_uart->port, flags); return NOTIFY_OK; } @@ -523,7 +523,7 @@ static int cdns_uart_clk_notifier_cb(str * frequency. */ - spin_lock_irqsave(&cdns_uart->port->lock, flags); + uart_port_lock_irqsave(cdns_uart->port, &flags); locked = 1; port->uartclk = ndata->new_rate; @@ -533,7 +533,7 @@ static int cdns_uart_clk_notifier_cb(str fallthrough; case ABORT_RATE_CHANGE: if (!locked) - spin_lock_irqsave(&cdns_uart->port->lock, flags); + uart_port_lock_irqsave(cdns_uart->port, &flags); /* Set TX/RX Reset */ ctrl_reg = readl(port->membase + CDNS_UART_CR); @@ -555,7 +555,7 @@ static int cdns_uart_clk_notifier_cb(str ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; writel(ctrl_reg, port->membase + CDNS_UART_CR); - spin_unlock_irqrestore(&cdns_uart->port->lock, flags); + uart_port_unlock_irqrestore(cdns_uart->port, flags); return NOTIFY_OK; default: @@ -652,7 +652,7 @@ static void cdns_uart_break_ctl(struct u unsigned int status; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); status = readl(port->membase + CDNS_UART_CR); @@ -664,7 +664,7 @@ static void cdns_uart_break_ctl(struct u writel(CDNS_UART_CR_STOPBRK | status, port->membase + CDNS_UART_CR); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /** @@ -683,7 +683,7 @@ static void cdns_uart_set_termios(struct unsigned long flags; unsigned int ctrl_reg, mode_reg; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable the TX and RX to set baud rate */ ctrl_reg = readl(port->membase + CDNS_UART_CR); @@ -794,7 +794,7 @@ static void cdns_uart_set_termios(struct cval &= ~CDNS_UART_MODEMCR_FCM; writel(cval, port->membase + CDNS_UART_MODEMCR); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /** @@ -813,7 +813,7 @@ static int cdns_uart_startup(struct uart is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable the TX and RX */ writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, @@ -861,7 +861,7 @@ static int cdns_uart_startup(struct uart writel(readl(port->membase + CDNS_UART_ISR), port->membase + CDNS_UART_ISR); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port); if (ret) { @@ -889,7 +889,7 @@ static void cdns_uart_shutdown(struct ua int status; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable interrupts */ status = readl(port->membase + CDNS_UART_IMR); @@ -900,7 +900,7 @@ static void cdns_uart_shutdown(struct ua writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, port->membase + CDNS_UART_CR); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); free_irq(port->irq, port); } @@ -1050,7 +1050,7 @@ static int cdns_uart_poll_get_char(struc int c; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Check if FIFO is empty */ if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY) @@ -1058,7 +1058,7 @@ static int cdns_uart_poll_get_char(struc else /* Read a character */ c = (unsigned char) readl(port->membase + CDNS_UART_FIFO); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return c; } @@ -1067,7 +1067,7 @@ static void cdns_uart_poll_put_char(stru { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Wait until FIFO is empty */ while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) @@ -1080,7 +1080,7 @@ static void cdns_uart_poll_put_char(stru while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) cpu_relax(); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } #endif @@ -1232,9 +1232,9 @@ static void cdns_uart_console_write(stru if (port->sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock_irqsave(&port->lock, flags); + locked = uart_port_trylock_irqsave(port, &flags); else - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* save and disable interrupt */ imr = readl(port->membase + CDNS_UART_IMR); @@ -1257,7 +1257,7 @@ static void cdns_uart_console_write(stru writel(imr, port->membase + CDNS_UART_IER); if (locked) - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /** @@ -1325,7 +1325,7 @@ static int cdns_uart_suspend(struct devi if (console_suspend_enabled && uart_console(port) && may_wake) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Empty the receive FIFO 1st before making changes */ while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)) @@ -1334,7 +1334,7 @@ static int cdns_uart_suspend(struct devi writel(1, port->membase + CDNS_UART_RXWM); /* disable RX timeout interrups */ writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* @@ -1372,7 +1372,7 @@ static int cdns_uart_resume(struct devic return ret; } - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Set TX/RX Reset */ ctrl_reg = readl(port->membase + CDNS_UART_CR); @@ -1392,14 +1392,14 @@ static int cdns_uart_resume(struct devic clk_disable(cdns_uart->uartclk); clk_disable(cdns_uart->pclk); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } else { - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* restore original rx trigger level */ writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); /* enable RX timeout interrupt */ writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } return uart_resume_port(cdns_uart->cdns_uart_driver, port);