[v2,2/2] watchdog: mediatek: mt7988: add wdt support

Add support for watchdog and reset generator unit of the MediaTek
MT7988 SoC.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
v2: call new toprgu_reset_sw_en_unlocked from toprgu_reset_update while
    holding lock.

 drivers/watchdog/mtk_wdt.c | 40 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

On Mon, Nov 13, 2023 at 03:43:47PM +0000, Daniel Golle wrote:
> Add support for watchdog and reset generator unit of the MediaTek
> MT7988 SoC.
> 
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> v2: call new toprgu_reset_sw_en_unlocked from toprgu_reset_update while
>     holding lock.
> 
>  drivers/watchdog/mtk_wdt.c | 40 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index b2330b16b497a..5a31a8746e954 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -58,6 +58,8 @@
>  #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"
>  
> @@ -71,10 +73,12 @@ struct mtk_wdt_dev {
>  	struct reset_controller_dev rcdev;
>  	bool disable_wdt_extrst;
>  	bool reset_by_toprgu;
> +	bool has_swsysrst_en;
>  };
>  
>  struct mtk_wdt_data {
>  	int toprgu_sw_rst_num;
> +	bool has_swsysrst_en;
>  };
>  
>  static const struct mtk_wdt_data mt2712_data = {
> @@ -89,6 +93,11 @@ static const struct mtk_wdt_data mt7986_data = {
>  	.toprgu_sw_rst_num = MT7986_TOPRGU_SW_RST_NUM,
>  };
>  
> +static const struct mtk_wdt_data mt7988_data = {
> +	.toprgu_sw_rst_num = 24,
> +	.has_swsysrst_en = true,
> +};
> +
>  static const struct mtk_wdt_data mt8183_data = {
>  	.toprgu_sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
>  };
> @@ -109,6 +118,28 @@ static const struct mtk_wdt_data mt8195_data = {
>  	.toprgu_sw_rst_num = MT8195_TOPRGU_SW_RST_NUM,
>  };
>  
> +/**
> + * toprgu_reset_sw_en_unlocked() - enable/disable software control for reset bit
> + * @mtk_wdt: Pointer to instance of struct mtk_wdt_dev.
> + * @id: Bit number identifying the reset to be enabled or disabled.
> + * @enable: If true, enable software control for that bit, disable otherwise.
> + *
> + * Context: The caller must hold lock of struct mtk_wdt_dev.
> + */
> +static void toprgu_reset_sw_en_unlocked(struct mtk_wdt_dev *data,
> +					unsigned long id, bool enable)
> +{
> +	u32 tmp;
> +
> +	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);
> +}
> +
>  static int toprgu_reset_update(struct reset_controller_dev *rcdev,
>  			       unsigned long id, bool assert)
>  {
> @@ -119,6 +150,9 @@ static int toprgu_reset_update(struct reset_controller_dev *rcdev,
>  
>  	spin_lock_irqsave(&data->lock, flags);
>  
> +	if (assert && data->has_swsysrst_en)
> +		toprgu_reset_sw_en_unlocked(data, id, true);
> +
>  	tmp = readl(data->wdt_base + WDT_SWSYSRST);
>  	if (assert)
>  		tmp |= BIT(id);
> @@ -127,6 +161,9 @@ static int toprgu_reset_update(struct reset_controller_dev *rcdev,
>  	tmp |= WDT_SWSYS_RST_KEY;
>  	writel(tmp, data->wdt_base + WDT_SWSYSRST);
>  
> +	if (!assert && data->has_swsysrst_en)
> +		toprgu_reset_sw_en_unlocked(data, id, false);
> +
>  	spin_unlock_irqrestore(&data->lock, flags);
>  
>  	return 0;
> @@ -406,6 +443,8 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>  						       wdt_data->toprgu_sw_rst_num);
>  		if (err)
>  			return err;
> +
> +		mtk_wdt->has_swsysrst_en = wdt_data->has_swsysrst_en;
>  	}
>  
>  	mtk_wdt->disable_wdt_extrst =
> @@ -444,6 +483,7 @@ static const struct of_device_id mtk_wdt_dt_ids[] = {
>  	{ .compatible = "mediatek,mt6589-wdt" },
>  	{ .compatible = "mediatek,mt6795-wdt", .data = &mt6795_data },
>  	{ .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data },
> +	{ .compatible = "mediatek,mt7988-wdt", .data = &mt7988_data },
>  	{ .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
>  	{ .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data },
>  	{ .compatible = "mediatek,mt8188-wdt", .data = &mt8188_data },
> -- 
> 2.42.1