* [PATCH] watchdog: renesas_wdt: Add a few cycles delay
@ 2019-06-05 5:04 Yoshihiro Shimoda
2019-06-05 5:21 ` Yoshihiro Shimoda
2019-06-07 17:44 ` [PATCH v3] " Guenter Roeck
0 siblings, 2 replies; 4+ messages in thread
From: Yoshihiro Shimoda @ 2019-06-05 5:04 UTC (permalink / raw)
To: wim, linux; +Cc: linux-watchdog, linux-renesas-soc, Yoshihiro Shimoda
According to the hardware manual of R-Car Gen2 and Gen3,
software should wait a few RLCK cycles as following:
- Delay 2 cycles before setting watchdog counter.
- Delay 3 cycles before disabling module clock.
So, this patch adds such delays.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
Changes from v2 (https://patchwork.kernel.org/patch/10972721/):
- Rename the wait function name.
- Rename the variable name in the wait function.
- Change variable type.
- Add Wolfram-san and Niklas-san's Reviewed-by.
Changes from v1 (https://patchwork.kernel.org/patch/10972641/):
- Change formula to improve accuracy.
- Add Geert-san's Reviewed-by.
drivers/watchdog/renesas_wdt.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 565dbc1..0cfc0e9 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -7,6 +7,7 @@
*/
#include <linux/bitops.h>
#include <linux/clk.h>
+#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -70,6 +71,15 @@ static int rwdt_init_timeout(struct watchdog_device *wdev)
return 0;
}
+static void rwdt_wait_cycles(struct rwdt_priv *priv, unsigned int cycles)
+{
+ unsigned int delay;
+
+ delay = DIV_ROUND_UP(cycles * 1000000, priv->clk_rate);
+
+ usleep_range(delay, 2 * delay);
+}
+
static int rwdt_start(struct watchdog_device *wdev)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
@@ -80,6 +90,8 @@ static int rwdt_start(struct watchdog_device *wdev)
/* Stop the timer before we modify any register */
val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
rwdt_write(priv, val, RWTCSRA);
+ /* Delay 2 cycles before setting watchdog counter */
+ rwdt_wait_cycles(priv, 2);
rwdt_init_timeout(wdev);
rwdt_write(priv, priv->cks, RWTCSRA);
@@ -98,6 +110,8 @@ static int rwdt_stop(struct watchdog_device *wdev)
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
rwdt_write(priv, priv->cks, RWTCSRA);
+ /* Delay 3 cycles before disabling module clock */
+ rwdt_wait_cycles(priv, 3);
pm_runtime_put(wdev->parent);
return 0;
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* RE: [PATCH] watchdog: renesas_wdt: Add a few cycles delay
2019-06-05 5:04 [PATCH] watchdog: renesas_wdt: Add a few cycles delay Yoshihiro Shimoda
@ 2019-06-05 5:21 ` Yoshihiro Shimoda
2019-06-07 17:44 ` [PATCH v3] " Guenter Roeck
1 sibling, 0 replies; 4+ messages in thread
From: Yoshihiro Shimoda @ 2019-06-05 5:21 UTC (permalink / raw)
To: Yoshihiro Shimoda, wim, linux; +Cc: linux-watchdog, linux-renesas-soc
> From: Yoshihiro Shimoda, Sent: Wednesday, June 5, 2019 2:04 PM
> Subject: [PATCH] watchdog: renesas_wdt: Add a few cycles delay
Oops, I should have submitted as "PATCH v3" on the subject...
Best regards,
Yoshihiro Shimoda
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3] watchdog: renesas_wdt: Add a few cycles delay
2019-06-05 5:04 [PATCH] watchdog: renesas_wdt: Add a few cycles delay Yoshihiro Shimoda
2019-06-05 5:21 ` Yoshihiro Shimoda
@ 2019-06-07 17:44 ` Guenter Roeck
2019-06-13 9:28 ` Simon Horman
1 sibling, 1 reply; 4+ messages in thread
From: Guenter Roeck @ 2019-06-07 17:44 UTC (permalink / raw)
To: Yoshihiro Shimoda; +Cc: wim, linux-watchdog, linux-renesas-soc
[Note: I updated the subject to "PATCH v3"]
On Wed, Jun 05, 2019 at 02:04:00PM +0900, Yoshihiro Shimoda wrote:
> According to the hardware manual of R-Car Gen2 and Gen3,
> software should wait a few RLCK cycles as following:
> - Delay 2 cycles before setting watchdog counter.
> - Delay 3 cycles before disabling module clock.
>
> So, this patch adds such delays.
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Changes from v2 (https://patchwork.kernel.org/patch/10972721/):
> - Rename the wait function name.
> - Rename the variable name in the wait function.
> - Change variable type.
> - Add Wolfram-san and Niklas-san's Reviewed-by.
>
> Changes from v1 (https://patchwork.kernel.org/patch/10972641/):
> - Change formula to improve accuracy.
> - Add Geert-san's Reviewed-by.
>
> drivers/watchdog/renesas_wdt.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
> index 565dbc1..0cfc0e9 100644
> --- a/drivers/watchdog/renesas_wdt.c
> +++ b/drivers/watchdog/renesas_wdt.c
> @@ -7,6 +7,7 @@
> */
> #include <linux/bitops.h>
> #include <linux/clk.h>
> +#include <linux/delay.h>
> #include <linux/io.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> @@ -70,6 +71,15 @@ static int rwdt_init_timeout(struct watchdog_device *wdev)
> return 0;
> }
>
> +static void rwdt_wait_cycles(struct rwdt_priv *priv, unsigned int cycles)
> +{
> + unsigned int delay;
> +
> + delay = DIV_ROUND_UP(cycles * 1000000, priv->clk_rate);
> +
> + usleep_range(delay, 2 * delay);
> +}
> +
> static int rwdt_start(struct watchdog_device *wdev)
> {
> struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
> @@ -80,6 +90,8 @@ static int rwdt_start(struct watchdog_device *wdev)
> /* Stop the timer before we modify any register */
> val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
> rwdt_write(priv, val, RWTCSRA);
> + /* Delay 2 cycles before setting watchdog counter */
> + rwdt_wait_cycles(priv, 2);
>
> rwdt_init_timeout(wdev);
> rwdt_write(priv, priv->cks, RWTCSRA);
> @@ -98,6 +110,8 @@ static int rwdt_stop(struct watchdog_device *wdev)
> struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
>
> rwdt_write(priv, priv->cks, RWTCSRA);
> + /* Delay 3 cycles before disabling module clock */
> + rwdt_wait_cycles(priv, 3);
> pm_runtime_put(wdev->parent);
>
> return 0;
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3] watchdog: renesas_wdt: Add a few cycles delay
2019-06-07 17:44 ` [PATCH v3] " Guenter Roeck
@ 2019-06-13 9:28 ` Simon Horman
0 siblings, 0 replies; 4+ messages in thread
From: Simon Horman @ 2019-06-13 9:28 UTC (permalink / raw)
To: Guenter Roeck; +Cc: Yoshihiro Shimoda, wim, linux-watchdog, linux-renesas-soc
On Fri, Jun 07, 2019 at 10:44:11AM -0700, Guenter Roeck wrote:
> [Note: I updated the subject to "PATCH v3"]
>
> On Wed, Jun 05, 2019 at 02:04:00PM +0900, Yoshihiro Shimoda wrote:
> > According to the hardware manual of R-Car Gen2 and Gen3,
> > software should wait a few RLCK cycles as following:
> > - Delay 2 cycles before setting watchdog counter.
> > - Delay 3 cycles before disabling module clock.
> >
> > So, this patch adds such delays.
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-06-05 5:04 [PATCH] watchdog: renesas_wdt: Add a few cycles delay Yoshihiro Shimoda
2019-06-05 5:21 ` Yoshihiro Shimoda
2019-06-07 17:44 ` [PATCH v3] " Guenter Roeck
2019-06-13 9:28 ` Simon Horman
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