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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/watchdog/bcm2835_wdt.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/watchdog/bcm2835_wdt.c')
-rw-r--r--drivers/watchdog/bcm2835_wdt.c249
1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
new file mode 100644
index 000000000..55c0f7b0e
--- /dev/null
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for Broadcom BCM2835
+ *
+ * "bcm2708_wdog" driver written by Luke Diamand that was obtained from
+ * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
+ * as a hardware reference for the Broadcom BCM2835 watchdog timer.
+ *
+ * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/types.h>
+#include <linux/mfd/bcm2835-pm.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#define PM_RSTC 0x1c
+#define PM_RSTS 0x20
+#define PM_WDOG 0x24
+
+#define PM_PASSWORD 0x5a000000
+
+#define PM_WDOG_TIME_SET 0x000fffff
+#define PM_RSTC_WRCFG_CLR 0xffffffcf
+#define PM_RSTS_HADWRH_SET 0x00000040
+#define PM_RSTC_WRCFG_SET 0x00000030
+#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
+#define PM_RSTC_RESET 0x00000102
+
+/*
+ * The Raspberry Pi firmware uses the RSTS register to know which partition
+ * to boot from. The partition value is spread into bits 0, 2, 4, 6, 8, 10.
+ * Partition 63 is a special partition used by the firmware to indicate halt.
+ */
+#define PM_RSTS_RASPBERRYPI_HALT 0x555
+
+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
+#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
+#define WDOG_TICKS_TO_MSECS(x) ((x) * 1000 >> 16)
+
+struct bcm2835_wdt {
+ void __iomem *base;
+ spinlock_t lock;
+};
+
+static struct bcm2835_wdt *bcm2835_power_off_wdt;
+
+static unsigned int heartbeat;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
+{
+ uint32_t cur;
+
+ cur = readl(wdt->base + PM_RSTC);
+
+ return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
+}
+
+static int bcm2835_wdt_start(struct watchdog_device *wdog)
+{
+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+ uint32_t cur;
+ unsigned long flags;
+
+ spin_lock_irqsave(&wdt->lock, flags);
+
+ writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
+ PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
+ cur = readl_relaxed(wdt->base + PM_RSTC);
+ writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
+ PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
+
+ spin_unlock_irqrestore(&wdt->lock, flags);
+
+ return 0;
+}
+
+static int bcm2835_wdt_stop(struct watchdog_device *wdog)
+{
+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
+ return 0;
+}
+
+static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
+ return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
+}
+
+static void __bcm2835_restart(struct bcm2835_wdt *wdt)
+{
+ u32 val;
+
+ /* use a timeout of 10 ticks (~150us) */
+ writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
+ val = readl_relaxed(wdt->base + PM_RSTC);
+ val &= PM_RSTC_WRCFG_CLR;
+ val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
+ writel_relaxed(val, wdt->base + PM_RSTC);
+
+ /* No sleeping, possibly atomic. */
+ mdelay(1);
+}
+
+static int bcm2835_restart(struct watchdog_device *wdog,
+ unsigned long action, void *data)
+{
+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ __bcm2835_restart(wdt);
+
+ return 0;
+}
+
+static const struct watchdog_ops bcm2835_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = bcm2835_wdt_start,
+ .stop = bcm2835_wdt_stop,
+ .get_timeleft = bcm2835_wdt_get_timeleft,
+ .restart = bcm2835_restart,
+};
+
+static const struct watchdog_info bcm2835_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+ .identity = "Broadcom BCM2835 Watchdog timer",
+};
+
+static struct watchdog_device bcm2835_wdt_wdd = {
+ .info = &bcm2835_wdt_info,
+ .ops = &bcm2835_wdt_ops,
+ .min_timeout = 1,
+ .max_hw_heartbeat_ms = WDOG_TICKS_TO_MSECS(PM_WDOG_TIME_SET),
+ .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
+};
+
+/*
+ * We can't really power off, but if we do the normal reset scheme, and
+ * indicate to bootcode.bin not to reboot, then most of the chip will be
+ * powered off.
+ */
+static void bcm2835_power_off(void)
+{
+ struct bcm2835_wdt *wdt = bcm2835_power_off_wdt;
+ u32 val;
+
+ /*
+ * We set the watchdog hard reset bit here to distinguish this reset
+ * from the normal (full) reset. bootcode.bin will not reboot after a
+ * hard reset.
+ */
+ val = readl_relaxed(wdt->base + PM_RSTS);
+ val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
+ writel_relaxed(val, wdt->base + PM_RSTS);
+
+ /* Continue with normal reset mechanism */
+ __bcm2835_restart(wdt);
+}
+
+static int bcm2835_wdt_probe(struct platform_device *pdev)
+{
+ struct bcm2835_pm *pm = dev_get_drvdata(pdev->dev.parent);
+ struct device *dev = &pdev->dev;
+ struct bcm2835_wdt *wdt;
+ int err;
+
+ wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ spin_lock_init(&wdt->lock);
+
+ wdt->base = pm->base;
+
+ watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
+ watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
+ watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
+ bcm2835_wdt_wdd.parent = dev;
+ if (bcm2835_wdt_is_running(wdt)) {
+ /*
+ * The currently active timeout value (set by the
+ * bootloader) may be different from the module
+ * heartbeat parameter or the value in device
+ * tree. But we just need to set WDOG_HW_RUNNING,
+ * because then the framework will "immediately" ping
+ * the device, updating the timeout.
+ */
+ set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
+ }
+
+ watchdog_set_restart_priority(&bcm2835_wdt_wdd, 128);
+
+ watchdog_stop_on_reboot(&bcm2835_wdt_wdd);
+ err = devm_watchdog_register_device(dev, &bcm2835_wdt_wdd);
+ if (err)
+ return err;
+
+ if (of_device_is_system_power_controller(pdev->dev.parent->of_node)) {
+ if (!pm_power_off) {
+ pm_power_off = bcm2835_power_off;
+ bcm2835_power_off_wdt = wdt;
+ } else {
+ dev_info(dev, "Poweroff handler already present!\n");
+ }
+ }
+
+ dev_info(dev, "Broadcom BCM2835 watchdog timer");
+ return 0;
+}
+
+static int bcm2835_wdt_remove(struct platform_device *pdev)
+{
+ if (pm_power_off == bcm2835_power_off)
+ pm_power_off = NULL;
+
+ return 0;
+}
+
+static struct platform_driver bcm2835_wdt_driver = {
+ .probe = bcm2835_wdt_probe,
+ .remove = bcm2835_wdt_remove,
+ .driver = {
+ .name = "bcm2835-wdt",
+ },
+};
+module_platform_driver(bcm2835_wdt_driver);
+
+module_param(heartbeat, uint, 0);
+MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_ALIAS("platform:bcm2835-wdt");
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
+MODULE_LICENSE("GPL");