Re: [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore
Hello, On Wed, Sep 05, 2018 at 09:24:26AM +0800, Anson Huang wrote: > 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 > --- > drivers/tty/serial/imx.c | 12 +++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index 239c0fa..c15332d 100644 Acked-by: Uwe Kleine-König Thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König| Industrial Linux Solutions | http://www.pengutronix.de/ |
Re: [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore
Hello, On Wed, Sep 05, 2018 at 09:24:26AM +0800, Anson Huang wrote: > 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 > --- > drivers/tty/serial/imx.c | 12 +++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index 239c0fa..c15332d 100644 Acked-by: Uwe Kleine-König Thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König| Industrial Linux Solutions | http://www.pengutronix.de/ |
[PATCH V2 1/2] 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
---
drivers/tty/serial/imx.c | 12 +++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 239c0fa..c15332d 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2376,8 +2376,13 @@ 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(>port.lock, flags);
+ if (!sport->context_saved) {
+ spin_unlock_irqrestore(>port.lock, flags);
return;
+ }
imx_uart_writel(sport, sport->saved_reg[4], UFCR);
imx_uart_writel(sport, sport->saved_reg[5], UESC);
@@ -2390,11 +2395,15 @@ 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(>port.lock, flags);
}
static void imx_uart_save_context(struct imx_port *sport)
{
+ unsigned long flags;
+
/* Save necessary regs */
+ spin_lock_irqsave(>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);
@@ -2406,6 +2415,7 @@ 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(>port.lock, flags);
}
static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
--
2.7.4
[PATCH V2 1/2] 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
---
drivers/tty/serial/imx.c | 12 +++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 239c0fa..c15332d 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2376,8 +2376,13 @@ 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(>port.lock, flags);
+ if (!sport->context_saved) {
+ spin_unlock_irqrestore(>port.lock, flags);
return;
+ }
imx_uart_writel(sport, sport->saved_reg[4], UFCR);
imx_uart_writel(sport, sport->saved_reg[5], UESC);
@@ -2390,11 +2395,15 @@ 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(>port.lock, flags);
}
static void imx_uart_save_context(struct imx_port *sport)
{
+ unsigned long flags;
+
/* Save necessary regs */
+ spin_lock_irqsave(>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);
@@ -2406,6 +2415,7 @@ 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(>port.lock, flags);
}
static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
--
2.7.4
