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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/watchdog/dw_wdt.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/watchdog/dw_wdt.c')
-rw-r--r--drivers/watchdog/dw_wdt.c699
1 files changed, 699 insertions, 0 deletions
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
new file mode 100644
index 0000000000..84dca3695f
--- /dev/null
+++ b/drivers/watchdog/dw_wdt.c
@@ -0,0 +1,699 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2010-2011 Picochip Ltd., Jamie Iles
+ * https://www.picochip.com
+ *
+ * This file implements a driver for the Synopsys DesignWare watchdog device
+ * in the many subsystems. The watchdog has 16 different timeout periods
+ * and these are a function of the input clock frequency.
+ *
+ * The DesignWare watchdog cannot be stopped once it has been started so we
+ * do not implement a stop function. The watchdog core will continue to send
+ * heartbeat requests after the watchdog device has been closed.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/reset.h>
+#include <linux/watchdog.h>
+
+#define WDOG_CONTROL_REG_OFFSET 0x00
+#define WDOG_CONTROL_REG_WDT_EN_MASK 0x01
+#define WDOG_CONTROL_REG_RESP_MODE_MASK 0x02
+#define WDOG_TIMEOUT_RANGE_REG_OFFSET 0x04
+#define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT 4
+#define WDOG_CURRENT_COUNT_REG_OFFSET 0x08
+#define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c
+#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76
+#define WDOG_INTERRUPT_STATUS_REG_OFFSET 0x10
+#define WDOG_INTERRUPT_CLEAR_REG_OFFSET 0x14
+#define WDOG_COMP_PARAMS_5_REG_OFFSET 0xe4
+#define WDOG_COMP_PARAMS_4_REG_OFFSET 0xe8
+#define WDOG_COMP_PARAMS_3_REG_OFFSET 0xec
+#define WDOG_COMP_PARAMS_2_REG_OFFSET 0xf0
+#define WDOG_COMP_PARAMS_1_REG_OFFSET 0xf4
+#define WDOG_COMP_PARAMS_1_USE_FIX_TOP BIT(6)
+#define WDOG_COMP_VERSION_REG_OFFSET 0xf8
+#define WDOG_COMP_TYPE_REG_OFFSET 0xfc
+
+/* 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) ")");
+
+enum dw_wdt_rmod {
+ DW_WDT_RMOD_RESET = 1,
+ DW_WDT_RMOD_IRQ = 2
+};
+
+struct dw_wdt_timeout {
+ u32 top_val;
+ unsigned int sec;
+ unsigned int msec;
+};
+
+struct dw_wdt {
+ void __iomem *regs;
+ struct clk *clk;
+ struct clk *pclk;
+ unsigned long rate;
+ enum dw_wdt_rmod rmod;
+ struct dw_wdt_timeout timeouts[DW_WDT_NUM_TOPS];
+ struct watchdog_device wdd;
+ struct reset_control *rst;
+ /* Save/restore */
+ u32 control;
+ u32 timeout;
+
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *dbgfs_dir;
+#endif
+};
+
+#define to_dw_wdt(wdd) container_of(wdd, struct dw_wdt, wdd)
+
+static inline int dw_wdt_is_enabled(struct dw_wdt *dw_wdt)
+{
+ return readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET) &
+ WDOG_CONTROL_REG_WDT_EN_MASK;
+}
+
+static void dw_wdt_update_mode(struct dw_wdt *dw_wdt, enum dw_wdt_rmod rmod)
+{
+ u32 val;
+
+ val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+ if (rmod == DW_WDT_RMOD_IRQ)
+ val |= WDOG_CONTROL_REG_RESP_MODE_MASK;
+ else
+ val &= ~WDOG_CONTROL_REG_RESP_MODE_MASK;
+ writel(val, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+
+ dw_wdt->rmod = rmod;
+}
+
+static unsigned int dw_wdt_find_best_top(struct dw_wdt *dw_wdt,
+ unsigned int timeout, u32 *top_val)
+{
+ int idx;
+
+ /*
+ * 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.
+ */
+ 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 unsigned int dw_wdt_get_min_timeout(struct dw_wdt *dw_wdt)
+{
+ 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->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;
+ }
+
+ /*
+ * In IRQ mode due to the two stages counter, the actual timeout is
+ * twice greater than the TOP setting.
+ */
+ return dw_wdt->timeouts[idx].sec * dw_wdt->rmod;
+}
+
+static int dw_wdt_ping(struct watchdog_device *wdd)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt->regs +
+ WDOG_COUNTER_RESTART_REG_OFFSET);
+
+ return 0;
+}
+
+static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+ unsigned int timeout;
+ u32 top_val;
+
+ /*
+ * Note IRQ mode being enabled means having a non-zero pre-timeout
+ * setup. In this case we try to find a TOP as close to the half of the
+ * requested timeout as possible since DW Watchdog IRQ mode is designed
+ * in two stages way - first timeout rises the pre-timeout interrupt,
+ * second timeout performs the system reset. So basically the effective
+ * watchdog-caused reset happens after two watchdog TOPs elapsed.
+ */
+ timeout = dw_wdt_find_best_top(dw_wdt, DIV_ROUND_UP(top_s, dw_wdt->rmod),
+ &top_val);
+ if (dw_wdt->rmod == DW_WDT_RMOD_IRQ)
+ wdd->pretimeout = timeout;
+ else
+ wdd->pretimeout = 0;
+
+ /*
+ * Set the new value in the watchdog. Some versions of dw_wdt
+ * have TOPINIT in the TIMEOUT_RANGE register (as per
+ * CP_WDT_DUAL_TOP in WDT_COMP_PARAMS_1). On those we
+ * effectively get a pat of the watchdog right here.
+ */
+ writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
+ dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+
+ /* Kick new TOP value into the watchdog counter if activated. */
+ if (watchdog_active(wdd))
+ dw_wdt_ping(wdd);
+
+ /*
+ * In case users set bigger timeout value than HW can support,
+ * kernel(watchdog_dev.c) helps to feed watchdog before
+ * wdd->max_hw_heartbeat_ms
+ */
+ if (top_s * 1000 <= wdd->max_hw_heartbeat_ms)
+ wdd->timeout = timeout * dw_wdt->rmod;
+ else
+ wdd->timeout = top_s;
+
+ return 0;
+}
+
+static int dw_wdt_set_pretimeout(struct watchdog_device *wdd, unsigned int req)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ /*
+ * We ignore actual value of the timeout passed from user-space
+ * using it as a flag whether the pretimeout functionality is intended
+ * to be activated.
+ */
+ dw_wdt_update_mode(dw_wdt, req ? DW_WDT_RMOD_IRQ : DW_WDT_RMOD_RESET);
+ dw_wdt_set_timeout(wdd, wdd->timeout);
+
+ return 0;
+}
+
+static void dw_wdt_arm_system_reset(struct dw_wdt *dw_wdt)
+{
+ u32 val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+
+ /* Disable/enable interrupt mode depending on the RMOD flag. */
+ if (dw_wdt->rmod == DW_WDT_RMOD_IRQ)
+ val |= WDOG_CONTROL_REG_RESP_MODE_MASK;
+ else
+ val &= ~WDOG_CONTROL_REG_RESP_MODE_MASK;
+ /* Enable watchdog. */
+ val |= WDOG_CONTROL_REG_WDT_EN_MASK;
+ writel(val, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+}
+
+static int dw_wdt_start(struct watchdog_device *wdd)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ dw_wdt_set_timeout(wdd, wdd->timeout);
+ dw_wdt_ping(&dw_wdt->wdd);
+ dw_wdt_arm_system_reset(dw_wdt);
+
+ return 0;
+}
+
+static int dw_wdt_stop(struct watchdog_device *wdd)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ if (!dw_wdt->rst) {
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+ return 0;
+ }
+
+ reset_control_assert(dw_wdt->rst);
+ reset_control_deassert(dw_wdt->rst);
+
+ return 0;
+}
+
+static int dw_wdt_restart(struct watchdog_device *wdd,
+ unsigned long action, void *data)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ writel(0, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+ dw_wdt_update_mode(dw_wdt, DW_WDT_RMOD_RESET);
+ if (dw_wdt_is_enabled(dw_wdt))
+ writel(WDOG_COUNTER_RESTART_KICK_VALUE,
+ dw_wdt->regs + WDOG_COUNTER_RESTART_REG_OFFSET);
+ else
+ dw_wdt_arm_system_reset(dw_wdt);
+
+ /* wait for reset to assert... */
+ mdelay(500);
+
+ return 0;
+}
+
+static unsigned int dw_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+ unsigned int sec;
+ u32 val;
+
+ val = readl(dw_wdt->regs + WDOG_CURRENT_COUNT_REG_OFFSET);
+ sec = val / dw_wdt->rate;
+
+ if (dw_wdt->rmod == DW_WDT_RMOD_IRQ) {
+ val = readl(dw_wdt->regs + WDOG_INTERRUPT_STATUS_REG_OFFSET);
+ if (!val)
+ sec += wdd->pretimeout;
+ }
+
+ return sec;
+}
+
+static const struct watchdog_info dw_wdt_ident = {
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+ WDIOF_MAGICCLOSE,
+ .identity = "Synopsys DesignWare Watchdog",
+};
+
+static const struct watchdog_info dw_wdt_pt_ident = {
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+ WDIOF_PRETIMEOUT | WDIOF_MAGICCLOSE,
+ .identity = "Synopsys DesignWare Watchdog",
+};
+
+static const struct watchdog_ops dw_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = dw_wdt_start,
+ .stop = dw_wdt_stop,
+ .ping = dw_wdt_ping,
+ .set_timeout = dw_wdt_set_timeout,
+ .set_pretimeout = dw_wdt_set_pretimeout,
+ .get_timeleft = dw_wdt_get_timeleft,
+ .restart = dw_wdt_restart,
+};
+
+static irqreturn_t dw_wdt_irq(int irq, void *devid)
+{
+ struct dw_wdt *dw_wdt = devid;
+ u32 val;
+
+ /*
+ * We don't clear the IRQ status. It's supposed to be done by the
+ * following ping operations.
+ */
+ val = readl(dw_wdt->regs + WDOG_INTERRUPT_STATUS_REG_OFFSET);
+ if (!val)
+ return IRQ_NONE;
+
+ watchdog_notify_pretimeout(&dw_wdt->wdd);
+
+ return IRQ_HANDLED;
+}
+
+static int dw_wdt_suspend(struct device *dev)
+{
+ struct dw_wdt *dw_wdt = dev_get_drvdata(dev);
+
+ dw_wdt->control = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+ dw_wdt->timeout = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+
+ clk_disable_unprepare(dw_wdt->pclk);
+ clk_disable_unprepare(dw_wdt->clk);
+
+ return 0;
+}
+
+static int dw_wdt_resume(struct device *dev)
+{
+ struct dw_wdt *dw_wdt = dev_get_drvdata(dev);
+ int err = clk_prepare_enable(dw_wdt->clk);
+
+ if (err)
+ return err;
+
+ err = clk_prepare_enable(dw_wdt->pclk);
+ if (err) {
+ clk_disable_unprepare(dw_wdt->clk);
+ return err;
+ }
+
+ writel(dw_wdt->timeout, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+ writel(dw_wdt->control, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+
+ dw_wdt_ping(&dw_wdt->wdd);
+
+ return 0;
+}
+
+static DEFINE_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;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+#define DW_WDT_DBGFS_REG(_name, _off) \
+{ \
+ .name = _name, \
+ .offset = _off \
+}
+
+static const struct debugfs_reg32 dw_wdt_dbgfs_regs[] = {
+ DW_WDT_DBGFS_REG("cr", WDOG_CONTROL_REG_OFFSET),
+ DW_WDT_DBGFS_REG("torr", WDOG_TIMEOUT_RANGE_REG_OFFSET),
+ DW_WDT_DBGFS_REG("ccvr", WDOG_CURRENT_COUNT_REG_OFFSET),
+ DW_WDT_DBGFS_REG("crr", WDOG_COUNTER_RESTART_REG_OFFSET),
+ DW_WDT_DBGFS_REG("stat", WDOG_INTERRUPT_STATUS_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param5", WDOG_COMP_PARAMS_5_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param4", WDOG_COMP_PARAMS_4_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param3", WDOG_COMP_PARAMS_3_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param2", WDOG_COMP_PARAMS_2_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param1", WDOG_COMP_PARAMS_1_REG_OFFSET),
+ DW_WDT_DBGFS_REG("version", WDOG_COMP_VERSION_REG_OFFSET),
+ DW_WDT_DBGFS_REG("type", WDOG_COMP_TYPE_REG_OFFSET)
+};
+
+static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt)
+{
+ struct device *dev = dw_wdt->wdd.parent;
+ struct debugfs_regset32 *regset;
+
+ regset = devm_kzalloc(dev, sizeof(*regset), GFP_KERNEL);
+ if (!regset)
+ return;
+
+ regset->regs = dw_wdt_dbgfs_regs;
+ regset->nregs = ARRAY_SIZE(dw_wdt_dbgfs_regs);
+ regset->base = dw_wdt->regs;
+
+ dw_wdt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
+
+ debugfs_create_regset32("registers", 0444, dw_wdt->dbgfs_dir, regset);
+}
+
+static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt)
+{
+ debugfs_remove_recursive(dw_wdt->dbgfs_dir);
+}
+
+#else /* !CONFIG_DEBUG_FS */
+
+static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt) {}
+static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt) {}
+
+#endif /* !CONFIG_DEBUG_FS */
+
+static int dw_wdt_drv_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct watchdog_device *wdd;
+ struct dw_wdt *dw_wdt;
+ int ret;
+
+ dw_wdt = devm_kzalloc(dev, sizeof(*dw_wdt), GFP_KERNEL);
+ if (!dw_wdt)
+ return -ENOMEM;
+
+ dw_wdt->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(dw_wdt->regs))
+ return PTR_ERR(dw_wdt->regs);
+
+ /*
+ * Try to request the watchdog dedicated timer clock source. It must
+ * be supplied if asynchronous mode is enabled. Otherwise fallback
+ * to the common timer/bus clocks configuration, in which the very
+ * first found clock supply both timer and APB signals.
+ */
+ dw_wdt->clk = devm_clk_get_enabled(dev, "tclk");
+ if (IS_ERR(dw_wdt->clk)) {
+ dw_wdt->clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(dw_wdt->clk))
+ return PTR_ERR(dw_wdt->clk);
+ }
+
+ dw_wdt->rate = clk_get_rate(dw_wdt->clk);
+ if (dw_wdt->rate == 0)
+ return -EINVAL;
+
+ /*
+ * Request APB clock if device is configured with async clocks mode.
+ * In this case both tclk and pclk clocks are supposed to be specified.
+ * Alas we can't know for sure whether async mode was really activated,
+ * so the pclk phandle reference is left optional. If it couldn't be
+ * found we consider the device configured in synchronous clocks mode.
+ */
+ dw_wdt->pclk = devm_clk_get_optional_enabled(dev, "pclk");
+ if (IS_ERR(dw_wdt->pclk))
+ return PTR_ERR(dw_wdt->pclk);
+
+ dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+ if (IS_ERR(dw_wdt->rst))
+ return PTR_ERR(dw_wdt->rst);
+
+ /* Enable normal reset without pre-timeout by default. */
+ dw_wdt_update_mode(dw_wdt, DW_WDT_RMOD_RESET);
+
+ /*
+ * Pre-timeout IRQ is optional, since some hardware may lack support
+ * of it. Note we must request rising-edge IRQ, since the lane is left
+ * pending either until the next watchdog kick event or up to the
+ * system reset.
+ */
+ ret = platform_get_irq_optional(pdev, 0);
+ if (ret > 0) {
+ ret = devm_request_irq(dev, ret, dw_wdt_irq,
+ IRQF_SHARED | IRQF_TRIGGER_RISING,
+ pdev->name, dw_wdt);
+ if (ret)
+ return ret;
+
+ dw_wdt->wdd.info = &dw_wdt_pt_ident;
+ } else {
+ if (ret == -EPROBE_DEFER)
+ return ret;
+
+ dw_wdt->wdd.info = &dw_wdt_ident;
+ }
+
+ reset_control_deassert(dw_wdt->rst);
+
+ ret = dw_wdt_init_timeouts(dw_wdt, dev);
+ if (ret)
+ goto out_assert_rst;
+
+ wdd = &dw_wdt->wdd;
+ wdd->ops = &dw_wdt_ops;
+ 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);
+ watchdog_set_nowayout(wdd, nowayout);
+ watchdog_init_timeout(wdd, 0, dev);
+
+ /*
+ * If the watchdog is already running, use its already configured
+ * timeout. Otherwise use the default or the value provided through
+ * devicetree.
+ */
+ if (dw_wdt_is_enabled(dw_wdt)) {
+ wdd->timeout = dw_wdt_get_timeout(dw_wdt);
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+ } else {
+ wdd->timeout = DW_WDT_DEFAULT_SECONDS;
+ watchdog_init_timeout(wdd, 0, dev);
+ }
+
+ platform_set_drvdata(pdev, dw_wdt);
+
+ watchdog_set_restart_priority(wdd, 128);
+ watchdog_stop_on_reboot(wdd);
+
+ ret = watchdog_register_device(wdd);
+ if (ret)
+ goto out_assert_rst;
+
+ dw_wdt_dbgfs_init(dw_wdt);
+
+ return 0;
+
+out_assert_rst:
+ reset_control_assert(dw_wdt->rst);
+ return ret;
+}
+
+static void dw_wdt_drv_remove(struct platform_device *pdev)
+{
+ struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);
+
+ dw_wdt_dbgfs_clear(dw_wdt);
+
+ watchdog_unregister_device(&dw_wdt->wdd);
+ reset_control_assert(dw_wdt->rst);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id dw_wdt_of_match[] = {
+ { .compatible = "snps,dw-wdt", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dw_wdt_of_match);
+#endif
+
+static struct platform_driver dw_wdt_driver = {
+ .probe = dw_wdt_drv_probe,
+ .remove_new = dw_wdt_drv_remove,
+ .driver = {
+ .name = "dw_wdt",
+ .of_match_table = of_match_ptr(dw_wdt_of_match),
+ .pm = pm_sleep_ptr(&dw_wdt_pm_ops),
+ },
+};
+
+module_platform_driver(dw_wdt_driver);
+
+MODULE_AUTHOR("Jamie Iles");
+MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
+MODULE_LICENSE("GPL");