From 07b5e16e9830878291bc83df70e87cdb0833517c Mon Sep 17 00:00:00 2001 From: Anson Huang Date: Wed, 5 Sep 2018 09:24:26 +0800 Subject: tty: serial: imx: add lock for registers save/restore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In noirq suspend/resume stage with no_console_suspend enabled, imx_uart_console_write() may be called to print out log_buf message by printk(), so there will be race condition between imx_uart_console_write() and imx_uart_save/restore_context(), need to add lock to protect the registers save/restore operations. Signed-off-by: Anson Huang Acked-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 3069ee93583e..2634272ad0fb 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2371,8 +2371,13 @@ static int imx_uart_remove(struct platform_device *pdev) static void imx_uart_restore_context(struct imx_port *sport) { - if (!sport->context_saved) + unsigned long flags; + + spin_lock_irqsave(&sport->port.lock, flags); + if (!sport->context_saved) { + spin_unlock_irqrestore(&sport->port.lock, flags); return; + } imx_uart_writel(sport, sport->saved_reg[4], UFCR); imx_uart_writel(sport, sport->saved_reg[5], UESC); @@ -2385,11 +2390,15 @@ static void imx_uart_restore_context(struct imx_port *sport) imx_uart_writel(sport, sport->saved_reg[2], UCR3); imx_uart_writel(sport, sport->saved_reg[3], UCR4); sport->context_saved = false; + spin_unlock_irqrestore(&sport->port.lock, flags); } static void imx_uart_save_context(struct imx_port *sport) { + unsigned long flags; + /* Save necessary regs */ + spin_lock_irqsave(&sport->port.lock, flags); sport->saved_reg[0] = imx_uart_readl(sport, UCR1); sport->saved_reg[1] = imx_uart_readl(sport, UCR2); sport->saved_reg[2] = imx_uart_readl(sport, UCR3); @@ -2401,6 +2410,7 @@ static void imx_uart_save_context(struct imx_port *sport) sport->saved_reg[8] = imx_uart_readl(sport, UBMR); sport->saved_reg[9] = imx_uart_readl(sport, IMX21_UTS); sport->context_saved = true; + spin_unlock_irqrestore(&sport->port.lock, flags); } static void imx_uart_enable_wakeup(struct imx_port *sport, bool on) -- cgit v1.2.3