Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 226 insertions, 0 deletions

diff --git a/drivers/watchdog/pic32-dmt.c b/drivers/watchdog/pic32-dmt.c
new file mode 100644
index 0000000000..ab0682492c
--- /dev/null
+++ b/drivers/watchdog/pic32-dmt.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PIC32 deadman timer driver
+ *
+ * Purna Chandra Mandal <purna.mandal@microchip.com>
+ * Copyright (c) 2016, Microchip Technology Inc.
+ */
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/watchdog.h>
+
+#include <asm/mach-pic32/pic32.h>
+
+/* Deadman Timer Regs */
+#define DMTCON_REG	0x00
+#define DMTPRECLR_REG	0x10
+#define DMTCLR_REG	0x20
+#define DMTSTAT_REG	0x30
+#define DMTCNT_REG	0x40
+#define DMTPSCNT_REG	0x60
+#define DMTPSINTV_REG	0x70
+
+/* Deadman Timer Regs fields */
+#define DMT_ON			BIT(15)
+#define DMT_STEP1_KEY		BIT(6)
+#define DMT_STEP2_KEY		BIT(3)
+#define DMTSTAT_WINOPN		BIT(0)
+#define DMTSTAT_EVENT		BIT(5)
+#define DMTSTAT_BAD2		BIT(6)
+#define DMTSTAT_BAD1		BIT(7)
+
+/* Reset Control Register fields for watchdog */
+#define RESETCON_DMT_TIMEOUT	BIT(5)
+
+struct pic32_dmt {
+	void __iomem	*regs;
+	struct clk	*clk;
+};
+
+static inline void dmt_enable(struct pic32_dmt *dmt)
+{
+	writel(DMT_ON, PIC32_SET(dmt->regs + DMTCON_REG));
+}
+
+static inline void dmt_disable(struct pic32_dmt *dmt)
+{
+	writel(DMT_ON, PIC32_CLR(dmt->regs + DMTCON_REG));
+	/*
+	 * Cannot touch registers in the CPU cycle following clearing the
+	 * ON bit.
+	 */
+	nop();
+}
+
+static inline int dmt_bad_status(struct pic32_dmt *dmt)
+{
+	u32 val;
+
+	val = readl(dmt->regs + DMTSTAT_REG);
+	val &= (DMTSTAT_BAD1 | DMTSTAT_BAD2 | DMTSTAT_EVENT);
+	if (val)
+		return -EAGAIN;
+
+	return 0;
+}
+
+static inline int dmt_keepalive(struct pic32_dmt *dmt)
+{
+	u32 v;
+	u32 timeout = 500;
+
+	/* set pre-clear key */
+	writel(DMT_STEP1_KEY << 8, dmt->regs + DMTPRECLR_REG);
+
+	/* wait for DMT window to open */
+	while (--timeout) {
+		v = readl(dmt->regs + DMTSTAT_REG) & DMTSTAT_WINOPN;
+		if (v == DMTSTAT_WINOPN)
+			break;
+	}
+
+	/* apply key2 */
+	writel(DMT_STEP2_KEY, dmt->regs + DMTCLR_REG);
+
+	/* check whether keys are latched correctly */
+	return dmt_bad_status(dmt);
+}
+
+static inline u32 pic32_dmt_get_timeout_secs(struct pic32_dmt *dmt)
+{
+	unsigned long rate;
+
+	rate = clk_get_rate(dmt->clk);
+	if (rate)
+		return readl(dmt->regs + DMTPSCNT_REG) / rate;
+
+	return 0;
+}
+
+static inline u32 pic32_dmt_bootstatus(struct pic32_dmt *dmt)
+{
+	u32 v;
+	void __iomem *rst_base;
+
+	rst_base = ioremap(PIC32_BASE_RESET, 0x10);
+	if (!rst_base)
+		return 0;
+
+	v = readl(rst_base);
+
+	writel(RESETCON_DMT_TIMEOUT, PIC32_CLR(rst_base));
+
+	iounmap(rst_base);
+	return v & RESETCON_DMT_TIMEOUT;
+}
+
+static int pic32_dmt_start(struct watchdog_device *wdd)
+{
+	struct pic32_dmt *dmt = watchdog_get_drvdata(wdd);
+
+	dmt_enable(dmt);
+	return dmt_keepalive(dmt);
+}
+
+static int pic32_dmt_stop(struct watchdog_device *wdd)
+{
+	struct pic32_dmt *dmt = watchdog_get_drvdata(wdd);
+
+	dmt_disable(dmt);
+
+	return 0;
+}
+
+static int pic32_dmt_ping(struct watchdog_device *wdd)
+{
+	struct pic32_dmt *dmt = watchdog_get_drvdata(wdd);
+
+	return dmt_keepalive(dmt);
+}
+
+static const struct watchdog_ops pic32_dmt_fops = {
+	.owner		= THIS_MODULE,
+	.start		= pic32_dmt_start,
+	.stop		= pic32_dmt_stop,
+	.ping		= pic32_dmt_ping,
+};
+
+static const struct watchdog_info pic32_dmt_ident = {
+	.options	= WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+	.identity	= "PIC32 Deadman Timer",
+};
+
+static struct watchdog_device pic32_dmt_wdd = {
+	.info		= &pic32_dmt_ident,
+	.ops		= &pic32_dmt_fops,
+};
+
+static int pic32_dmt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int ret;
+	struct pic32_dmt *dmt;
+	struct watchdog_device *wdd = &pic32_dmt_wdd;
+
+	dmt = devm_kzalloc(dev, sizeof(*dmt), GFP_KERNEL);
+	if (!dmt)
+		return -ENOMEM;
+
+	dmt->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dmt->regs))
+		return PTR_ERR(dmt->regs);
+
+	dmt->clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(dmt->clk)) {
+		dev_err(dev, "clk not found\n");
+		return PTR_ERR(dmt->clk);
+	}
+
+	wdd->timeout = pic32_dmt_get_timeout_secs(dmt);
+	if (!wdd->timeout) {
+		dev_err(dev, "failed to read watchdog register timeout\n");
+		return -EINVAL;
+	}
+
+	dev_info(dev, "timeout %d\n", wdd->timeout);
+
+	wdd->bootstatus = pic32_dmt_bootstatus(dmt) ? WDIOF_CARDRESET : 0;
+
+	watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
+	watchdog_set_drvdata(wdd, dmt);
+
+	ret = devm_watchdog_register_device(dev, wdd);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, wdd);
+	return 0;
+}
+
+static const struct of_device_id pic32_dmt_of_ids[] = {
+	{ .compatible = "microchip,pic32mzda-dmt",},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pic32_dmt_of_ids);
+
+static struct platform_driver pic32_dmt_driver = {
+	.probe		= pic32_dmt_probe,
+	.driver		= {
+		.name		= "pic32-dmt",
+		.of_match_table = of_match_ptr(pic32_dmt_of_ids),
+	}
+};
+
+module_platform_driver(pic32_dmt_driver);
+
+MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>");
+MODULE_DESCRIPTION("Microchip PIC32 DMT Driver");
+MODULE_LICENSE("GPL");