Re: [PATCH v5 2/2] watchdog: mtk_wdt: mt8183: Add reset controller

[Guenter Roeck <linux@roeck-us.net>]

On 12/2/19 7:02 PM, Yong Liang wrote:
> On Mon, 2019-12-02 at 21:02 +0800, Philipp Zabel wrote:
>> On Fri, 2019-11-29 at 16:36 +0800, Yong Liang wrote:
>>> On Mon, 2019-11-25 at 17:51 +0800, Philipp Zabel wrote:
>>>> On Sun, 2019-11-24 at 22:16 -0800, Guenter Roeck wrote:
>>>>> On Mon, Nov 25, 2019 at 11:03:50AM +0800, Jiaxin Yu wrote:
>>>>>> From: "yong.liang" <yong.liang@mediatek.com>
>>>>>>
>>>>>> Add reset controller API in watchdog driver.
>>>>>> Besides watchdog, MTK toprgu module also provide sub-system (eg, audio,
>>>>>> camera, codec and connectivity) software reset functionality.
>>>>>>
>>>>>> Signed-off-by: yong.liang <yong.liang@mediatek.com>
>>>>>> Signed-off-by: jiaxin.yu <jiaxin.yu@mediatek.com>
>>>>>> Reviewed-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
>>>>>> ---
>>>>>>   drivers/watchdog/Kconfig   |   1 +
>>>>>>   drivers/watchdog/mtk_wdt.c | 111 ++++++++++++++++++++++++++++++++++++-
>>>>>>   2 files changed, 111 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..d29484c7940a 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>
>>>>>>   #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 +61,99 @@ 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 sw_rst_num;
>>>>>>   };
>>>>>>   
>>>>>> +static const struct mtk_wdt_data mt2712_data = {
>>>>>> +	.sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
>>>>>> +};
>>>>>> +
>>>>>> +static const struct mtk_wdt_data mt8183_data = {
>>>>>> +	.sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
>>>>>> +};
>>>>>
>>>>> The number of resets can be set in .data directly; there is no need
>>>>> for the structures.
>>>
>>>      We want to put all properities in mtxxxx-resets.h and it easy to
>>> manager. If there are new properity in the feture, we can put it in
>>> mtk_wdt_data mtxxxx_data
>>
>> Do you expect there will be more properties in the future?
> 
>    Yes, We may put some infra reset bit and max number in mtxxxx-resets.h

Please either do that now or introduce the complexity when needed.

Thanks,
Guenter

>>
>>>>>> +static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
>>>>>> +				 unsigned long id)
>>>>>> +{
>>>>>> +	unsigned int tmp;
>>>>>> +	unsigned long flags;
>>>>>> +	struct mtk_wdt_dev *data =
>>>>>> +		 container_of(rcdev, struct mtk_wdt_dev, rcdev);
>>>>>> +
>>>>>> +	spin_lock_irqsave(&data->lock, flags);
>>>>>> +
>>>>>> +	tmp = __raw_readl(data->wdt_base + WDT_SWSYSRST);
>>>>>> +	tmp &= ~BIT(id);
>>>>>> +	tmp |= WDT_SWSYS_RST_KEY;
>>>>>> +	writel(tmp, data->wdt_base + WDT_SWSYSRST);
>>>>>> +
>>>>>> +	spin_unlock_irqrestore(&data->lock, flags);
>>>>>> +
>>>>>> +	return 0;
>>>>>> +}
>>>>>
>>>>> There is a lot of duplication in those functions. Only one line
>>>>> is different. I think this is a good example where a helper function
>>>>> with an additional argument indicating set or reset would be helpful.
>>>>>
>>>      .assert and .dessert are two numbers of struct reset_control_ops.
>>>       I think it's better to define both of them.
>>
>> The suggestion was to have two very short _assert and _deassert
>> functions that only contain a single call to a common helper function.
>> See the reset-a10sr.c driver for an example.
> 
>    OK. I will modify it as reset-a10sr.c do.
>>
>> regards
>> Philipp
>>
>>
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> 


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