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Date: Thu, 26 Dec 2019 15:41:49 +0800
From: Yong Liang <yong.liang@...iatek.com>
To: Philipp Zabel <p.zabel@...gutronix.de>
CC: Jiaxin Yu (俞家鑫)
<Jiaxin.Yu@...iatek.com>,
"wim@...ux-watchdog.org" <wim@...ux-watchdog.org>,
"linux@...ck-us.net" <linux@...ck-us.net>,
"matthias.bgg@...il.com" <matthias.bgg@...il.com>,
"linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-mediatek@...ts.infradead.org"
<linux-mediatek@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Yingjoe Chen (陳英洲)
<Yingjoe.Chen@...iatek.com>, "sboyd@...nel.org" <sboyd@...nel.org>
Subject: Re: [PATCH v6 2/2] watchdog: mtk_wdt: mt8183: Add reset controller
On Thu, 2019-12-12 at 00:44 +0800, Philipp Zabel wrote:
> Hi,
>
> On Thu, 2019-12-12 at 00:22 +0800, Jiaxin Yu wrote:
> > From: "yong.liang" <yong.liang@...iatek.com>
> >
> > Add reset controller API in watchdog driver.
> > Besides watchdog, MTK toprgu module alsa provide sub-system (eg, audio,
> > camera, codec and connectivity) software reset functionality.
>
> Do any of the listed sub-systems use the reset_control_reset()
> functionality? Is there no delay requirement between assert and
> deassert? Otherwise it would be safer not to implement the .reset()
> operation at all.
>
> > Audio use this reset API to reset audio, and it works well.
It is no need to add delay between assert and deassert.
> > Signed-off-by: yong.liang <yong.liang@...iatek.com>
> > ---
> > drivers/watchdog/Kconfig | 1 +
> > drivers/watchdog/mtk_wdt.c | 109 ++++++++++++++++++++++++++++++++++++-
> > 2 files changed, 109 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 2e07caab9db2..629249fe5305 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -717,6 +717,7 @@ config MEDIATEK_WATCHDOG
> > tristate "Mediatek SoCs watchdog support"
> > depends on ARCH_MEDIATEK || COMPILE_TEST
> > select WATCHDOG_CORE
> > + select RESET_CONTROLLER
> > help
> > Say Y here to include support for the watchdog timer
> > in Mediatek SoCs.
> > diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> > index 9c3d0033260d..667380031dfd 100644
> > --- a/drivers/watchdog/mtk_wdt.c
> > +++ b/drivers/watchdog/mtk_wdt.c
> > @@ -9,6 +9,9 @@
> > * Based on sunxi_wdt.c
> > */
> >
> > +#include <dt-bindings/reset-controller/mt2712-resets.h>
> > +#include <dt-bindings/reset-controller/mt8183-resets.h>
> > +#include <linux/delay.h>
> > #include <linux/err.h>
> > #include <linux/init.h>
> > #include <linux/io.h>
> > @@ -16,10 +19,12 @@
> > #include <linux/module.h>
> > #include <linux/moduleparam.h>
> > #include <linux/of.h>
> > +#include <linux/of_device.h>
> > #include <linux/platform_device.h>
> > +#include <linux/reset-controller.h>
> > +#include <linux/slab.h>
>
> What is this required for?
It is no use. I will remove it.
>
> > #include <linux/types.h>
> > #include <linux/watchdog.h>
> > -#include <linux/delay.h>
> >
> > #define WDT_MAX_TIMEOUT 31
> > #define WDT_MIN_TIMEOUT 1
> > @@ -44,6 +49,9 @@
> > #define WDT_SWRST 0x14
> > #define WDT_SWRST_KEY 0x1209
> >
> > +#define WDT_SWSYSRST 0x18U
> > +#define WDT_SWSYS_RST_KEY 0x88000000
> > +
> > #define DRV_NAME "mtk-wdt"
> > #define DRV_VERSION "1.0"
> >
> > @@ -53,8 +61,97 @@ static unsigned int timeout;
> > struct mtk_wdt_dev {
> > struct watchdog_device wdt_dev;
> > void __iomem *wdt_base;
> > + spinlock_t lock; /* protects WDT_SWSYSRST reg */
> > + struct reset_controller_dev rcdev;
> > +};
> > +
> > +struct mtk_wdt_data {
> > + int infracfg_sw_rst_num;
>
> This is not used at all, better remove it.
I will remove it.
>
> > + int toprgu_sw_rst_num;
> > +};
> > +
> > +static const struct mtk_wdt_data mt2712_data = {
> > + .toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
> > +};
> > +
> > +static const struct mtk_wdt_data mt8183_data = {
> > + .infracfg_sw_rst_num = MT8183_INFRACFG_SW_RST_NUM,
>
> Same as above.
I will remove it.
>
> > + .toprgu_sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
> > +};
> > +
> > +static int toprgu_reset_update(struct reset_controller_dev *rcdev,
> > + unsigned long id, bool assert)
> > +{
> > + unsigned int tmp;
> > + unsigned long flags;
> > +
>
> This empty line can be removed.
I will remove it.
>
> > + struct mtk_wdt_dev *data =
> > + container_of(rcdev, struct mtk_wdt_dev, rcdev);
> > +
> > + spin_lock_irqsave(&data->lock, flags);
> > +
> > + tmp = readl(data->wdt_base + WDT_SWSYSRST);
> > + if (assert)
> > + tmp |= BIT(id);
> > + else
> > + tmp &= ~BIT(id);
> > + tmp |= WDT_SWSYS_RST_KEY;
> > + writel(tmp, data->wdt_base + WDT_SWSYSRST);
> > +
> > + spin_unlock_irqrestore(&data->lock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +static int toprgu_reset_assert(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + return toprgu_reset_update(rcdev, id, true);
> > +}
> > +
> > +static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + return toprgu_reset_update(rcdev, id, false);
> > +}
> > +
> > +static int toprgu_reset(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + int ret;
> > +
> > + ret = toprgu_reset_assert(rcdev, id);
> > + if (ret)
> > + return ret;
> > +
> > + return toprgu_reset_deassert(rcdev, id);
> > +}
>
> As mentioned above, is this needed? Does this work for all modules?
> Only implement this if you are sure both are true.
I think it's safe. Many modules has used it in MTK inside.
>
> regards
> Philipp
>
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