linux-kernel - [PATCHv2 4/5] watchdog: rti-wdt: attach to running watchdog during probe

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Date:   Fri, 3 Jul 2020 15:04:05 +0300
From:   Tero Kristo <t-kristo@...com>
To:     <wim@...ux-watchdog.org>, <linux@...ck-us.net>,
        <linux-watchdog@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, <jan.kiszka@...mens.com>
Subject: [PATCHv2 4/5] watchdog: rti-wdt: attach to running watchdog during probe

If the RTI watchdog is running already during probe, the driver must
configure itself to match the HW. Window size and timeout is probed from
hardware, and the last keepalive ping is adjusted to match it also.

Signed-off-by: Tero Kristo <t-kristo@...com>
---
 drivers/watchdog/rti_wdt.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
index 110bfc8d0bb3..987e5a798cb4 100644
--- a/drivers/watchdog/rti_wdt.c
+++ b/drivers/watchdog/rti_wdt.c
@@ -213,6 +213,7 @@ static int rti_wdt_probe(struct platform_device *pdev)
 	struct watchdog_device *wdd;
 	struct rti_wdt_device *wdt;
 	struct clk *clk;
+	u32 last_ping = 0;
 
 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt)
@@ -258,11 +259,8 @@ static int rti_wdt_probe(struct platform_device *pdev)
 	wdd->min_timeout = 1;
 	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
 		wdt->freq * 1000;
-	wdd->timeout = DEFAULT_HEARTBEAT;
 	wdd->parent = dev;
 
-	watchdog_init_timeout(wdd, heartbeat, dev);
-
 	watchdog_set_drvdata(wdd, wdt);
 	watchdog_set_nowayout(wdd, 1);
 	watchdog_set_restart_priority(wdd, 128);
@@ -274,12 +272,34 @@ static int rti_wdt_probe(struct platform_device *pdev)
 		goto err_iomap;
 	}
 
+	if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) {
+		u32 time_left;
+
+		set_bit(WDOG_HW_RUNNING, &wdd->status);
+		time_left = rti_wdt_get_timeleft(wdd);
+		heartbeat = readl(wdt->base + RTIDWDPRLD);
+		heartbeat <<= WDT_PRELOAD_SHIFT;
+		heartbeat /= wdt->freq;
+
+		wsize = readl(wdt->base + RTIWWDSIZECTRL);
+		ret = rti_wdt_setup_hw_hb(wdd);
+		if (ret)
+			goto err_iomap;
+
+		last_ping = -(time_left - heartbeat) * 1000;
+	}
+
+	watchdog_init_timeout(wdd, heartbeat, dev);
+
 	ret = watchdog_register_device(wdd);
 	if (ret) {
 		dev_err(dev, "cannot register watchdog device\n");
 		goto err_iomap;
 	}
 
+	if (last_ping)
+		watchdog_set_last_hw_keepalive(wdd, last_ping);
+
 	return 0;
 
 err_iomap:
-- 
2.17.1

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