1 files changed, 167 insertions, 24 deletions

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index fba21de2bbad..693c0d1fd796 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -13,6 +13,8 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/limits.h>
+#include <linux/kernel.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
@@ -34,21 +36,40 @@
 #define WDOG_CURRENT_COUNT_REG_OFFSET	    0x08
 #define WDOG_COUNTER_RESTART_REG_OFFSET     0x0c
 #define WDOG_COUNTER_RESTART_KICK_VALUE	    0x76
+#define WDOG_COMP_PARAMS_1_REG_OFFSET       0xf4
+#define WDOG_COMP_PARAMS_1_USE_FIX_TOP      BIT(6)
 
-/* The maximum TOP (timeout period) value that can be set in the watchdog. */
-#define DW_WDT_MAX_TOP		15
+/* There are sixteen TOPs (timeout periods) that can be set in the watchdog. */
+#define DW_WDT_NUM_TOPS		16
+#define DW_WDT_FIX_TOP(_idx)	(1U << (16 + _idx))
 
 #define DW_WDT_DEFAULT_SECONDS	30
 
+static const u32 dw_wdt_fix_tops[DW_WDT_NUM_TOPS] = {
+	DW_WDT_FIX_TOP(0), DW_WDT_FIX_TOP(1), DW_WDT_FIX_TOP(2),
+	DW_WDT_FIX_TOP(3), DW_WDT_FIX_TOP(4), DW_WDT_FIX_TOP(5),
+	DW_WDT_FIX_TOP(6), DW_WDT_FIX_TOP(7), DW_WDT_FIX_TOP(8),
+	DW_WDT_FIX_TOP(9), DW_WDT_FIX_TOP(10), DW_WDT_FIX_TOP(11),
+	DW_WDT_FIX_TOP(12), DW_WDT_FIX_TOP(13), DW_WDT_FIX_TOP(14),
+	DW_WDT_FIX_TOP(15)
+};
+
 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 		 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+struct dw_wdt_timeout {
+	u32 top_val;
+	unsigned int sec;
+	unsigned int msec;
+};
+
 struct dw_wdt {
 	void __iomem		*regs;
 	struct clk		*clk;
 	unsigned long		rate;
+	struct dw_wdt_timeout	timeouts[DW_WDT_NUM_TOPS];
 	struct watchdog_device	wdd;
 	struct reset_control	*rst;
 	/* Save/restore */
@@ -64,20 +85,66 @@ static inline int dw_wdt_is_enabled(struct dw_wdt *dw_wdt)
 		WDOG_CONTROL_REG_WDT_EN_MASK;
 }
 
-static inline int dw_wdt_top_in_seconds(struct dw_wdt *dw_wdt, unsigned top)
+static unsigned int dw_wdt_find_best_top(struct dw_wdt *dw_wdt,
+					 unsigned int timeout, u32 *top_val)
 {
+	int idx;
+
 	/*
-	 * There are 16 possible timeout values in 0..15 where the number of
-	 * cycles is 2 ^ (16 + i) and the watchdog counts down.
+	 * Find a TOP with timeout greater or equal to the requested number.
+	 * Note we'll select a TOP with maximum timeout if the requested
+	 * timeout couldn't be reached.
 	 */
-	return (1U << (16 + top)) / dw_wdt->rate;
+	for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
+		if (dw_wdt->timeouts[idx].sec >= timeout)
+			break;
+	}
+
+	if (idx == DW_WDT_NUM_TOPS)
+		--idx;
+
+	*top_val = dw_wdt->timeouts[idx].top_val;
+
+	return dw_wdt->timeouts[idx].sec;
 }
 
-static int dw_wdt_get_top(struct dw_wdt *dw_wdt)
+static unsigned int dw_wdt_get_min_timeout(struct dw_wdt *dw_wdt)
 {
-	int top = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
+	int idx;
+
+	/*
+	 * We'll find a timeout greater or equal to one second anyway because
+	 * the driver probe would have failed if there was none.
+	 */
+	for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
+		if (dw_wdt->timeouts[idx].sec)
+			break;
+	}
 
-	return dw_wdt_top_in_seconds(dw_wdt, top);
+	return dw_wdt->timeouts[idx].sec;
+}
+
+static unsigned int dw_wdt_get_max_timeout_ms(struct dw_wdt *dw_wdt)
+{
+	struct dw_wdt_timeout *timeout = &dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1];
+	u64 msec;
+
+	msec = (u64)timeout->sec * MSEC_PER_SEC + timeout->msec;
+
+	return msec < UINT_MAX ? msec : UINT_MAX;
+}
+
+static unsigned int dw_wdt_get_timeout(struct dw_wdt *dw_wdt)
+{
+	int top_val = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
+	int idx;
+
+	for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
+		if (dw_wdt->timeouts[idx].top_val == top_val)
+			break;
+	}
+
+	return dw_wdt->timeouts[idx].sec;
 }
 
 static int dw_wdt_ping(struct watchdog_device *wdd)
@@ -93,17 +160,10 @@ static int dw_wdt_ping(struct watchdog_device *wdd)
 static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
 {
 	struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
-	int i, top_val = DW_WDT_MAX_TOP;
+	unsigned int timeout;
+	u32 top_val;
 
-	/*
-	 * Iterate over the timeout values until we find the closest match. We
-	 * always look for >=.
-	 */
-	for (i = 0; i <= DW_WDT_MAX_TOP; ++i)
-		if (dw_wdt_top_in_seconds(dw_wdt, i) >= top_s) {
-			top_val = i;
-			break;
-		}
+	timeout = dw_wdt_find_best_top(dw_wdt, top_s, &top_val);
 
 	/*
 	 * Set the new value in the watchdog.  Some versions of dw_wdt
@@ -120,7 +180,7 @@ static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
 	 * wdd->max_hw_heartbeat_ms
 	 */
 	if (top_s * 1000 <= wdd->max_hw_heartbeat_ms)
-		wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
+		wdd->timeout = timeout;
 	else
 		wdd->timeout = top_s;
 
@@ -238,6 +298,86 @@ static int dw_wdt_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);
 
+/*
+ * In case if DW WDT IP core is synthesized with fixed TOP feature disabled the
+ * TOPs array can be arbitrary ordered with nearly any sixteen uint numbers
+ * depending on the system engineer imagination. The next method handles the
+ * passed TOPs array to pre-calculate the effective timeouts and to sort the
+ * TOP items out in the ascending order with respect to the timeouts.
+ */
+
+static void dw_wdt_handle_tops(struct dw_wdt *dw_wdt, const u32 *tops)
+{
+	struct dw_wdt_timeout tout, *dst;
+	int val, tidx;
+	u64 msec;
+
+	/*
+	 * We walk over the passed TOPs array and calculate corresponding
+	 * timeouts in seconds and milliseconds. The milliseconds granularity
+	 * is needed to distinguish the TOPs with very close timeouts and to
+	 * set the watchdog max heartbeat setting further.
+	 */
+	for (val = 0; val < DW_WDT_NUM_TOPS; ++val) {
+		tout.top_val = val;
+		tout.sec = tops[val] / dw_wdt->rate;
+		msec = (u64)tops[val] * MSEC_PER_SEC;
+		do_div(msec, dw_wdt->rate);
+		tout.msec = msec - ((u64)tout.sec * MSEC_PER_SEC);
+
+		/*
+		 * Find a suitable place for the current TOP in the timeouts
+		 * array so that the list is remained in the ascending order.
+		 */
+		for (tidx = 0; tidx < val; ++tidx) {
+			dst = &dw_wdt->timeouts[tidx];
+			if (tout.sec > dst->sec || (tout.sec == dst->sec &&
+			    tout.msec >= dst->msec))
+				continue;
+			else
+				swap(*dst, tout);
+		}
+
+		dw_wdt->timeouts[val] = tout;
+	}
+}
+
+static int dw_wdt_init_timeouts(struct dw_wdt *dw_wdt, struct device *dev)
+{
+	u32 data, of_tops[DW_WDT_NUM_TOPS];
+	const u32 *tops;
+	int ret;
+
+	/*
+	 * Retrieve custom or fixed counter values depending on the
+	 * WDT_USE_FIX_TOP flag found in the component specific parameters
+	 * #1 register.
+	 */
+	data = readl(dw_wdt->regs + WDOG_COMP_PARAMS_1_REG_OFFSET);
+	if (data & WDOG_COMP_PARAMS_1_USE_FIX_TOP) {
+		tops = dw_wdt_fix_tops;
+	} else {
+		ret = of_property_read_variable_u32_array(dev_of_node(dev),
+			"snps,watchdog-tops", of_tops, DW_WDT_NUM_TOPS,
+			DW_WDT_NUM_TOPS);
+		if (ret < 0) {
+			dev_warn(dev, "No valid TOPs array specified\n");
+			tops = dw_wdt_fix_tops;
+		} else {
+			tops = of_tops;
+		}
+	}
+
+	/* Convert the specified TOPs into an array of watchdog timeouts. */
+	dw_wdt_handle_tops(dw_wdt, tops);
+	if (!dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1].sec) {
+		dev_err(dev, "No any valid TOP detected\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int dw_wdt_drv_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -275,12 +415,15 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
 
 	reset_control_deassert(dw_wdt->rst);
 
+	ret = dw_wdt_init_timeouts(dw_wdt, dev);
+	if (ret)
+		goto out_disable_clk;
+
 	wdd = &dw_wdt->wdd;
 	wdd->info = &dw_wdt_ident;
 	wdd->ops = &dw_wdt_ops;
-	wdd->min_timeout = 1;
-	wdd->max_hw_heartbeat_ms =
-		dw_wdt_top_in_seconds(dw_wdt, DW_WDT_MAX_TOP) * 1000;
+	wdd->min_timeout = dw_wdt_get_min_timeout(dw_wdt);
+	wdd->max_hw_heartbeat_ms = dw_wdt_get_max_timeout_ms(dw_wdt);
 	wdd->parent = dev;
 
 	watchdog_set_drvdata(wdd, dw_wdt);
@@ -293,7 +436,7 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
 	 * devicetree.
 	 */
 	if (dw_wdt_is_enabled(dw_wdt)) {
-		wdd->timeout = dw_wdt_get_top(dw_wdt);
+		wdd->timeout = dw_wdt_get_timeout(dw_wdt);
 		set_bit(WDOG_HW_RUNNING, &wdd->status);
 	} else {
 		wdd->timeout = DW_WDT_DEFAULT_SECONDS;