Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 247 insertions, 0 deletions

diff --git a/drivers/watchdog/rza_wdt.c b/drivers/watchdog/rza_wdt.c
new file mode 100644
index 0000000000..cb4901b3f7
--- /dev/null
+++ b/drivers/watchdog/rza_wdt.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/A Series WDT Driver
+ *
+ * Copyright (C) 2017 Renesas Electronics America, Inc.
+ * Copyright (C) 2017 Chris Brandt
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_TIMEOUT		30
+
+/* Watchdog Timer Registers */
+#define WTCSR			0
+#define WTCSR_MAGIC		0xA500
+#define WTSCR_WT		BIT(6)
+#define WTSCR_TME		BIT(5)
+#define WTSCR_CKS(i)		(i)
+
+#define WTCNT			2
+#define WTCNT_MAGIC		0x5A00
+
+#define WRCSR			4
+#define WRCSR_MAGIC		0x5A00
+#define WRCSR_RSTE		BIT(6)
+#define WRCSR_CLEAR_WOVF	0xA500	/* special value */
+
+/* The maximum CKS register setting value to get the longest timeout */
+#define CKS_3BIT		0x7
+#define CKS_4BIT		0xF
+
+#define DIVIDER_3BIT		16384	/* Clock divider when CKS = 0x7 */
+#define DIVIDER_4BIT		4194304	/* Clock divider when CKS = 0xF */
+
+struct rza_wdt {
+	struct watchdog_device wdev;
+	void __iomem *base;
+	struct clk *clk;
+	u8 count;
+	u8 cks;
+};
+
+static void rza_wdt_calc_timeout(struct rza_wdt *priv, int timeout)
+{
+	unsigned long rate = clk_get_rate(priv->clk);
+	unsigned int ticks;
+
+	if (priv->cks == CKS_4BIT) {
+		ticks = DIV_ROUND_UP(timeout * rate, DIVIDER_4BIT);
+
+		/*
+		 * Since max_timeout was set in probe, we know that the timeout
+		 * value passed will never calculate to a tick value greater
+		 * than 256.
+		 */
+		priv->count = 256 - ticks;
+
+	} else {
+		/* Start timer with longest timeout */
+		priv->count = 0;
+	}
+
+	pr_debug("%s: timeout set to %u (WTCNT=%d)\n", __func__,
+		 timeout, priv->count);
+}
+
+static int rza_wdt_start(struct watchdog_device *wdev)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	/* Stop timer */
+	writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
+
+	/* Must dummy read WRCSR:WOVF at least once before clearing */
+	readb(priv->base + WRCSR);
+	writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
+
+	rza_wdt_calc_timeout(priv, wdev->timeout);
+
+	writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
+	writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
+	writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME |
+	       WTSCR_CKS(priv->cks), priv->base + WTCSR);
+
+	return 0;
+}
+
+static int rza_wdt_stop(struct watchdog_device *wdev)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
+
+	return 0;
+}
+
+static int rza_wdt_ping(struct watchdog_device *wdev)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
+
+	pr_debug("%s: timeout = %u\n", __func__, wdev->timeout);
+
+	return 0;
+}
+
+static int rza_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
+{
+	wdev->timeout = timeout;
+	rza_wdt_start(wdev);
+	return 0;
+}
+
+static int rza_wdt_restart(struct watchdog_device *wdev, unsigned long action,
+			    void *data)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	/* Stop timer */
+	writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
+
+	/* Must dummy read WRCSR:WOVF at least once before clearing */
+	readb(priv->base + WRCSR);
+	writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
+
+	/*
+	 * Start timer with fastest clock source and only 1 clock left before
+	 * overflow with reset option enabled.
+	 */
+	writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
+	writew(WTCNT_MAGIC | 255, priv->base + WTCNT);
+	writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME, priv->base + WTCSR);
+
+	/*
+	 * Actually make sure the above sequence hits hardware before sleeping.
+	 */
+	wmb();
+
+	/* Wait for WDT overflow (reset) */
+	udelay(20);
+
+	return 0;
+}
+
+static const struct watchdog_info rza_wdt_ident = {
+	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+	.identity = "Renesas RZ/A WDT Watchdog",
+};
+
+static const struct watchdog_ops rza_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = rza_wdt_start,
+	.stop = rza_wdt_stop,
+	.ping = rza_wdt_ping,
+	.set_timeout = rza_set_timeout,
+	.restart = rza_wdt_restart,
+};
+
+static int rza_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rza_wdt *priv;
+	unsigned long rate;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk))
+		return PTR_ERR(priv->clk);
+
+	rate = clk_get_rate(priv->clk);
+	if (rate < 16384) {
+		dev_err(dev, "invalid clock rate (%ld)\n", rate);
+		return -ENOENT;
+	}
+
+	priv->wdev.info = &rza_wdt_ident;
+	priv->wdev.ops = &rza_wdt_ops;
+	priv->wdev.parent = dev;
+
+	priv->cks = (u8)(uintptr_t) of_device_get_match_data(dev);
+	if (priv->cks == CKS_4BIT) {
+		/* Assume slowest clock rate possible (CKS=0xF) */
+		priv->wdev.max_timeout = (DIVIDER_4BIT * U8_MAX) / rate;
+
+	} else if (priv->cks == CKS_3BIT) {
+		/* Assume slowest clock rate possible (CKS=7) */
+		rate /= DIVIDER_3BIT;
+
+		/*
+		 * Since the max possible timeout of our 8-bit count
+		 * register is less than a second, we must use
+		 * max_hw_heartbeat_ms.
+		 */
+		priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX) / rate;
+		dev_dbg(dev, "max hw timeout of %dms\n",
+			priv->wdev.max_hw_heartbeat_ms);
+	}
+
+	priv->wdev.min_timeout = 1;
+	priv->wdev.timeout = DEFAULT_TIMEOUT;
+
+	watchdog_init_timeout(&priv->wdev, 0, dev);
+	watchdog_set_drvdata(&priv->wdev, priv);
+
+	ret = devm_watchdog_register_device(dev, &priv->wdev);
+	if (ret)
+		dev_err(dev, "Cannot register watchdog device\n");
+
+	return ret;
+}
+
+static const struct of_device_id rza_wdt_of_match[] = {
+	{ .compatible = "renesas,r7s9210-wdt",	.data = (void *)CKS_4BIT, },
+	{ .compatible = "renesas,rza-wdt",	.data = (void *)CKS_3BIT, },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rza_wdt_of_match);
+
+static struct platform_driver rza_wdt_driver = {
+	.probe = rza_wdt_probe,
+	.driver = {
+		.name = "rza_wdt",
+		.of_match_table = rza_wdt_of_match,
+	},
+};
+
+module_platform_driver(rza_wdt_driver);
+
+MODULE_DESCRIPTION("Renesas RZ/A WDT Driver");
+MODULE_AUTHOR("Chris Brandt <chris.brandt@renesas.com>");
+MODULE_LICENSE("GPL v2");