Subject: [PATCH 2/4] WIP: watchdog: mtk_wdt: mt8183: Add reset controller

From: Jiaxin Yu <[email-masked]>
Date: Fri, 27 Sep 2019 17:26:55 +0800

From: "yong.liang" <[email-masked]>

Provide assert/deassert/reset API in watchdog driver.
Register reset controller for toprgu device in watchdog probe.

Signed-off-by: yong.liang <[email-masked]>
---
 drivers/watchdog/Kconfig   |   1 +
 drivers/watchdog/mtk_wdt.c | 110 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 110 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..660fb0e48d8e 100644
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -20,6 +20,10 @@
 #include <linux/types.h>
 #include <linux/watchdog.h>
 #include <linux/delay.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/reset.h>
+#include <linux/of_device.h>
 
 #define WDT_MAX_TIMEOUT		31
 #define WDT_MIN_TIMEOUT		1
@@ -44,17 +48,113 @@
 #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"
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
 static unsigned int timeout;
 
+struct toprgu_reset {
+	spinlock_t lock; /* Protects reset_controller access */
+	void __iomem *toprgu_swrst_base;
+	int regofs;
+	struct reset_controller_dev rcdev;
+};
+
 struct mtk_wdt_dev {
 	struct watchdog_device wdt_dev;
 	void __iomem *wdt_base;
+	struct toprgu_reset reset_controller;
+	const struct mtk_wdt_compatible *dev_comp;
+};
+
+struct mtk_wdt_compatible {
+	int sw_rst_num;
+};
+
+static int toprgu_reset_assert(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	unsigned int tmp;
+	unsigned long flags;
+	struct toprgu_reset *data = container_of(rcdev,
+				struct toprgu_reset, rcdev);
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	tmp = __raw_readl(data->toprgu_swrst_base + data->regofs);
+	tmp |= BIT(id);
+	tmp |= WDT_SWSYS_RST_KEY;
+	writel(tmp, data->toprgu_swrst_base + data->regofs);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	unsigned int tmp;
+	unsigned long flags;
+	struct toprgu_reset *data = container_of(rcdev,
+					struct toprgu_reset, rcdev);
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	tmp = __raw_readl(data->toprgu_swrst_base + data->regofs);
+	tmp &= ~BIT(id);
+	tmp |= WDT_SWSYS_RST_KEY;
+	writel(tmp, data->toprgu_swrst_base + data->regofs);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+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);
+}
+
+static struct reset_control_ops toprgu_reset_ops = {
+	.assert = toprgu_reset_assert,
+	.deassert = toprgu_reset_deassert,
+	.reset = toprgu_reset,
 };
 
+static void toprgu_register_reset_controller(struct platform_device *pdev,
+					     int regofs)
+{
+	int ret;
+	struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
+
+	spin_lock_init(&mtk_wdt->reset_controller.lock);
+
+	mtk_wdt->dev_comp = of_device_get_match_data(&pdev->dev);
+	mtk_wdt->reset_controller.toprgu_swrst_base = mtk_wdt->wdt_base;
+	mtk_wdt->reset_controller.regofs = regofs;
+	mtk_wdt->reset_controller.rcdev.owner = THIS_MODULE;
+	mtk_wdt->reset_controller.rcdev.nr_resets =
+				mtk_wdt->dev_comp->sw_rst_num;
+	mtk_wdt->reset_controller.rcdev.ops = &toprgu_reset_ops;
+	mtk_wdt->reset_controller.rcdev.of_node = pdev->dev.of_node;
+	ret = reset_controller_register(&mtk_wdt->reset_controller.rcdev);
+	if (ret != 0)
+		dev_err(&pdev->dev,
+			"couldn't register wdt reset controller: %d\n", ret);
+}
+
 static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
 			   unsigned long action, void *data)
 {
@@ -187,9 +287,12 @@ static int mtk_wdt_probe(struct platform_device *pdev)
 	if (unlikely(err))
 		return err;
 
-	dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
+	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
 		 mtk_wdt->wdt_dev.timeout, nowayout);
 
+	mtk_wdt->dev_comp = of_device_get_match_data(&pdev->dev);
+	if (mtk_wdt->dev_comp)
+		toprgu_register_reset_controller(pdev, WDT_SWSYSRST);
 	return 0;
 }
 
@@ -217,7 +320,12 @@ static int mtk_wdt_resume(struct device *dev)
 }
 #endif
 
+static const struct mtk_wdt_compatible mt8183_compat = {
+	.sw_rst_num = 18,
+};
+
 static const struct of_device_id mtk_wdt_dt_ids[] = {
+	{ .compatible = "mediatek,mt8183-wdt", .data = &mt8183_compat },
 	{ .compatible = "mediatek,mt6589-wdt" },
 	{ /* sentinel */ }
 };
-- 
2.18.0

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