* [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore
@ 2018-09-05 1:24 Anson Huang
2018-09-05 1:24 ` [PATCH V2 2/2] tty: serial: imx: add pinctrl sleep/default mode switch for suspend Anson Huang
2018-09-05 5:54 ` [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore Uwe Kleine-König
0 siblings, 2 replies; 4+ messages in thread
From: Anson Huang @ 2018-09-05 1:24 UTC (permalink / raw)
To: gregkh, jslaby, linux-serial, linux-kernel, u.kleine-koenig; +Cc: Linux-imx
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>
---
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(&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);
@@ -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(&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);
@@ -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(&sport->port.lock, flags);
}
static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH V2 2/2] tty: serial: imx: add pinctrl sleep/default mode switch for suspend
2018-09-05 1:24 [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore Anson Huang
@ 2018-09-05 1:24 ` Anson Huang
2018-09-05 5:55 ` Uwe Kleine-König
2018-09-05 5:54 ` [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore Uwe Kleine-König
1 sibling, 1 reply; 4+ messages in thread
From: Anson Huang @ 2018-09-05 1:24 UTC (permalink / raw)
To: gregkh, jslaby, linux-serial, linux-kernel, u.kleine-koenig; +Cc: Linux-imx
On some i.MX SoCs' low power mode, such as i.MX7D's LPSR(low power
state retention), UART iomux settings will be lost, need to add
pinctrl sleep/default mode switch during suspend/resume to make
sure UART iomux settings are correct after resume.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
drivers/tty/serial/imx.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index c15332d..6ccb5c4 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -24,6 +24,7 @@
#include <linux/serial.h>
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/rational.h>
#include <linux/slab.h>
#include <linux/of.h>
@@ -2449,6 +2450,8 @@ static int imx_uart_suspend_noirq(struct device *dev)
clk_disable(sport->clk_ipg);
+ pinctrl_pm_select_sleep_state(dev);
+
return 0;
}
@@ -2457,6 +2460,8 @@ static int imx_uart_resume_noirq(struct device *dev)
struct imx_port *sport = dev_get_drvdata(dev);
int ret;
+ pinctrl_pm_select_default_state(dev);
+
ret = clk_enable(sport->clk_ipg);
if (ret)
return ret;
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore
2018-09-05 1:24 [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore Anson Huang
2018-09-05 1:24 ` [PATCH V2 2/2] tty: serial: imx: add pinctrl sleep/default mode switch for suspend Anson Huang
@ 2018-09-05 5:54 ` Uwe Kleine-König
1 sibling, 0 replies; 4+ messages in thread
From: Uwe Kleine-König @ 2018-09-05 5:54 UTC (permalink / raw)
To: Anson Huang; +Cc: gregkh, jslaby, linux-serial, linux-kernel, Linux-imx
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 <Anson.Huang@nxp.com>
> ---
> 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 <u.kleine-koenig@pengutronix.de>
Thanks
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH V2 2/2] tty: serial: imx: add pinctrl sleep/default mode switch for suspend
2018-09-05 1:24 ` [PATCH V2 2/2] tty: serial: imx: add pinctrl sleep/default mode switch for suspend Anson Huang
@ 2018-09-05 5:55 ` Uwe Kleine-König
0 siblings, 0 replies; 4+ messages in thread
From: Uwe Kleine-König @ 2018-09-05 5:55 UTC (permalink / raw)
To: Anson Huang; +Cc: gregkh, jslaby, linux-serial, linux-kernel, Linux-imx
On Wed, Sep 05, 2018 at 09:24:27AM +0800, Anson Huang wrote:
> On some i.MX SoCs' low power mode, such as i.MX7D's LPSR(low power
> state retention), UART iomux settings will be lost, need to add
> pinctrl sleep/default mode switch during suspend/resume to make
> sure UART iomux settings are correct after resume.
>
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-09-05 5:55 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-09-05 1:24 [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore Anson Huang
2018-09-05 1:24 ` [PATCH V2 2/2] tty: serial: imx: add pinctrl sleep/default mode switch for suspend Anson Huang
2018-09-05 5:55 ` Uwe Kleine-König
2018-09-05 5:54 ` [PATCH V2 1/2] tty: serial: imx: add lock for registers save/restore Uwe Kleine-König
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