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tty: serial: imx: add lock for registers save/restore 

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 <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Anson Huang 2018-09-05 09:24:26 +08:00 committed by Greg Kroah-Hartman
parent c974991d26
commit 07b5e16e98
1 changed files with 11 additions and 1 deletions
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12
drivers/tty/serial/imx.c
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@ -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)