[PATCH 2/3] drivers: thermal: tsens: Add watchdog support

[Amit Kucheria <amit.kucheria@linaro.org>]

TSENS IP v2.3 onwards adds support for a watchdog to detect if the TSENS
HW FSM is frozen. Add support to detect and restart the FSM in the
driver. The watchdog is configured by the bootloader, we just enable the
feature in the kernel.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
---
 drivers/thermal/qcom/tsens-common.c | 41 +++++++++++++++++++++++++++++
 drivers/thermal/qcom/tsens-v2.c     | 10 +++++++
 drivers/thermal/qcom/tsens.h        | 12 +++++++++
 3 files changed, 63 insertions(+)

diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
index 2989cb952cdb..9432518502a7 100644
--- a/drivers/thermal/qcom/tsens-common.c
+++ b/drivers/thermal/qcom/tsens-common.c
@@ -378,6 +378,28 @@ irqreturn_t tsens_critical_irq_thread(int irq, void *data)
 	bool enable = true, disable = false;
 	unsigned long flags;
 	int temp, ret, i;
+	u32 wdog_status, wdog_count, ver_minor;
+
+	ret = regmap_field_read(priv->rf[VER_MINOR], &ver_minor);
+	if (ret)
+		return ret;
+
+	if (tsens_version(priv) > VER_1_X &&  ver_minor > 2) {
+		/* Watchdog is present only on v2.3+ */
+		ret = regmap_field_read(priv->rf[WDOG_BARK_STATUS], &wdog_status);
+		if (ret)
+			return ret;
+
+		/* Clear WDOG interrupt */
+		regmap_field_write(priv->rf[WDOG_BARK_CLEAR], 1);
+		regmap_field_write(priv->rf[WDOG_BARK_CLEAR], 0);
+
+		ret = regmap_field_read(priv->rf[WDOG_BARK_COUNT], &wdog_count);
+		if (ret)
+			return ret;
+		if (wdog_count)
+			dev_err(priv->dev, "%s: watchdog count: %d\n", __func__, wdog_count);
+	}
 
 	for (i = 0; i < priv->num_sensors; i++) {
 		struct tsens_sensor *s = &priv->sensor[i];
@@ -685,6 +707,7 @@ int __init init_common(struct tsens_priv *priv)
 {
 	void __iomem *tm_base, *srot_base;
 	struct device *dev = priv->dev;
+	u32 ver_minor;
 	struct resource *res;
 	u32 enabled;
 	int ret, i, j;
@@ -734,6 +757,9 @@ int __init init_common(struct tsens_priv *priv)
 			if (IS_ERR(priv->rf[i]))
 				return PTR_ERR(priv->rf[i]);
 		}
+		ret = regmap_field_read(priv->rf[VER_MINOR], &ver_minor);
+		if (ret)
+			goto err_put_device;
 	}
 
 	priv->rf[TSENS_EN] = devm_regmap_field_alloc(dev, priv->srot_map,
@@ -794,6 +820,21 @@ int __init init_common(struct tsens_priv *priv)
 		}
 	}
 
+	if (tsens_version(priv) > VER_1_X &&  ver_minor > 2) {
+		/* Watchdog is present only on v2.3+ */
+		for (i = 0, j = WDOG_BARK_STATUS; j <= CC_MON_MASK; i++, j++) {
+			priv->rf[j] = devm_regmap_field_alloc(dev, priv->tm_map,
+							      priv->fields[j]);
+			if (IS_ERR(priv->rf[j])) {
+				ret = PTR_ERR(priv->rf[j]);
+				goto err_put_device;
+			}
+		}
+		/* Enable WDOG and disable cycle completion monitoring */
+		regmap_field_write(priv->rf[WDOG_BARK_MASK], 0);
+		regmap_field_write(priv->rf[CC_MON_MASK], 1);
+	}
+
 	spin_lock_init(&priv->ul_lock);
 	tsens_enable_irq(priv);
 	tsens_debug_init(op);
diff --git a/drivers/thermal/qcom/tsens-v2.c b/drivers/thermal/qcom/tsens-v2.c
index 47d831df0803..4184850d1e42 100644
--- a/drivers/thermal/qcom/tsens-v2.c
+++ b/drivers/thermal/qcom/tsens-v2.c
@@ -24,6 +24,7 @@
 #define TM_Sn_CRITICAL_THRESHOLD_OFF	0x0060
 #define TM_Sn_STATUS_OFF		0x00a0
 #define TM_TRDY_OFF			0x00e4
+#define TM_WDOG_LOG_OFF		0x013c
 
 /* v2.x: 8996, 8998, sdm845 */
 
@@ -66,6 +67,15 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
 	REG_FIELD_SPLIT_BITS_0_15(CRIT_INT_CLEAR,  TM_CRITICAL_INT_CLEAR_OFF),
 	REG_FIELD_SPLIT_BITS_0_15(CRIT_INT_MASK,   TM_CRITICAL_INT_MASK_OFF),
 
+	/* WATCHDOG on v2.3 or later */
+	[WDOG_BARK_STATUS] = REG_FIELD(TM_CRITICAL_INT_STATUS_OFF, 31, 31),
+	[WDOG_BARK_CLEAR]  = REG_FIELD(TM_CRITICAL_INT_CLEAR_OFF,  31, 31),
+	[WDOG_BARK_MASK]   = REG_FIELD(TM_CRITICAL_INT_MASK_OFF,   31, 31),
+	[CC_MON_STATUS]    = REG_FIELD(TM_CRITICAL_INT_STATUS_OFF, 30, 30),
+	[CC_MON_CLEAR]     = REG_FIELD(TM_CRITICAL_INT_CLEAR_OFF,  30, 30),
+	[CC_MON_MASK]      = REG_FIELD(TM_CRITICAL_INT_MASK_OFF,   30, 30),
+	[WDOG_BARK_COUNT]  = REG_FIELD(TM_WDOG_LOG_OFF,             0,  7),
+
 	/* Sn_STATUS */
 	REG_FIELD_FOR_EACH_SENSOR16(LAST_TEMP,       TM_Sn_STATUS_OFF,  0,  11),
 	REG_FIELD_FOR_EACH_SENSOR16(VALID,           TM_Sn_STATUS_OFF, 21,  21),
diff --git a/drivers/thermal/qcom/tsens.h b/drivers/thermal/qcom/tsens.h
index 9b5a30533c52..7608e7877a7b 100644
--- a/drivers/thermal/qcom/tsens.h
+++ b/drivers/thermal/qcom/tsens.h
@@ -440,6 +440,18 @@ enum regfield_ids {
 	CRIT_THRESH_13,
 	CRIT_THRESH_14,
 	CRIT_THRESH_15,
+
+	/* WATCHDOG */
+	WDOG_BARK_STATUS,
+	WDOG_BARK_CLEAR,
+	WDOG_BARK_MASK,
+	WDOG_BARK_COUNT,
+
+	/* CYCLE COMPLETION MONITOR */
+	CC_MON_STATUS,
+	CC_MON_CLEAR,
+	CC_MON_MASK,
+
 	MIN_STATUS_0,		/* MIN threshold violated */
 	MIN_STATUS_1,
 	MIN_STATUS_2,
-- 
2.17.1