Re: [PATCH 2/2] watchdog: mediatek: mt7988: add wdt support

[AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>]

Il 10/11/23 01:30, Daniel Golle ha scritto:
> Add support for watchdog and reset generator unit of the MediaTek
> MT7988 SoC.
>
> Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
> ---
>   drivers/watchdog/mtk_wdt.c | 56 +++++++++++++++++++++++++++++++++++++-
>   1 file changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index b2330b16b497a..b98b8c29735aa 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -12,6 +12,7 @@
>   #include <dt-bindings/reset/mt2712-resets.h>
>   #include <dt-bindings/reset/mediatek,mt6795-resets.h>
>   #include <dt-bindings/reset/mt7986-resets.h>
> +#include <dt-bindings/reset/mediatek,mt7988-resets.h>
>   #include <dt-bindings/reset/mt8183-resets.h>
>   #include <dt-bindings/reset/mt8186-resets.h>
>   #include <dt-bindings/reset/mt8188-resets.h>
> @@ -58,6 +59,8 @@
>   #define WDT_SWSYSRST		0x18U
>   #define WDT_SWSYS_RST_KEY	0x88000000
>   
> +#define WDT_SWSYSRST_EN		0xfc
> +
>   #define DRV_NAME		"mtk-wdt"
>   #define DRV_VERSION		"1.0"
>   
> @@ -71,44 +74,85 @@ struct mtk_wdt_dev {
>   	struct reset_controller_dev rcdev;
>   	bool disable_wdt_extrst;
>   	bool reset_by_toprgu;
> +	bool has_swsysrst_en;

mtk_wdt_data is always a const and this has_swsysrst_en member is never supposed
to change during runtime.

At this point, just add a pointer to struct mtk_wdt_data in mtk_wdt_dev, then
instead of mtk_wdt->has_swsysrst_en you check mtk_wdt->pdata->has_swsysrst_en.

>   };
>   
>   struct mtk_wdt_data {
>   	int toprgu_sw_rst_num;
> +	bool has_swsysrst_en;
>   };
>   
>   static const struct mtk_wdt_data mt2712_data = {
>   	.toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,

false == 0; 0 is init default; this assignment is useless.

>   };
>   
>   static const struct mtk_wdt_data mt6795_data = {
>   	.toprgu_sw_rst_num = MT6795_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
>   };
>   
>   static const struct mtk_wdt_data mt7986_data = {
>   	.toprgu_sw_rst_num = MT7986_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
> +};
> +
> +static const struct mtk_wdt_data mt7988_data = {
> +	.toprgu_sw_rst_num = MT7988_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = true,
>   };
>   
>   static const struct mtk_wdt_data mt8183_data = {
>   	.toprgu_sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
>   };
>   
>   static const struct mtk_wdt_data mt8186_data = {
>   	.toprgu_sw_rst_num = MT8186_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
>   };
>   
>   static const struct mtk_wdt_data mt8188_data = {
>   	.toprgu_sw_rst_num = MT8188_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
>   };
>   
>   static const struct mtk_wdt_data mt8192_data = {
>   	.toprgu_sw_rst_num = MT8192_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
>   };
>   
>   static const struct mtk_wdt_data mt8195_data = {
>   	.toprgu_sw_rst_num = MT8195_TOPRGU_SW_RST_NUM,
> +	.has_swsysrst_en = false,
>   };
>   
> +static int toprgu_reset_sw_enable(struct reset_controller_dev *rcdev,
> +				  unsigned long id, bool enable)

I would transfer this logic inside of toprgu_reset_update() (not literally!).

Doing so means that you would change this function to become

/**
 * toprgu_reset_sw_en_unlocked - What this function does
 * params
 * warn about this *requiring* to be called in locked state
 * check kerneldoc documentation :)))
 */
static void toprgu_reset_sw_en_unlocked(struct mtk_wdt_dev *mtk_wdt,
					unsigned long id, bool assert)
{
	u32 tmp;

	tmp = readl....
	if (...
	blahblah

	return 0;
}

and then call it in toprgu_reset_update(), before spin_unlock_irqrestore() like

{
	stuff...
	....

	writel(.... SWSYSRST);

	if (data->pdata->has_swsysrst_en)
		toprgu_reset_sw_en_unlocked(data, id, assert);

	spin_unlock_irqrestore(...)

	return 0;
}

> +{
> +	unsigned int tmp;
> +	unsigned long flags;
> +	struct mtk_wdt_dev *data =
> +		 container_of(rcdev, struct mtk_wdt_dev, rcdev);
> +
> +	if (!data->has_swsysrst_en)
> +		return 0;
> +
> +	spin_lock_irqsave(&data->lock, flags);
> +
> +	tmp = readl(data->wdt_base + WDT_SWSYSRST_EN);
> +	if (enable)
> +		tmp |= BIT(id);
> +	else
> +		tmp &= ~BIT(id);
> +
> +	writel(tmp, data->wdt_base + WDT_SWSYSRST_EN);
> +
> +	spin_unlock_irqrestore(&data->lock, flags);
> +
> +	return 0;
> +}
> +
>   static int toprgu_reset_update(struct reset_controller_dev *rcdev,
>   			       unsigned long id, bool assert)
>   {
> @@ -135,13 +179,20 @@ static int toprgu_reset_update(struct reset_controller_dev *rcdev,
>   static int toprgu_reset_assert(struct reset_controller_dev *rcdev,
>   			       unsigned long id)
>   {
> +	int ret;
> +
> +	ret = toprgu_reset_sw_enable(rcdev, id, true);
> +	if (ret)
> +		return ret;
> +
>   	return toprgu_reset_update(rcdev, id, true);

...so you don't even touch this function...

>   }
>   
>   static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
>   				 unsigned long id)
>   {
> -	return toprgu_reset_update(rcdev, id, false);
> +	toprgu_reset_update(rcdev, id, false);
> +	return toprgu_reset_sw_enable(rcdev, id, false);

...nor that one.

>   }
>   
>   static int toprgu_reset(struct reset_controller_dev *rcdev,

Cheers!
Angelo