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373 lines
10 KiB
373 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Watchdog driver for Marvell Armada 37xx SoCs |
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* |
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* Author: Marek Behún <[email protected]> |
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*/ |
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#include <linux/clk.h> |
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#include <linux/err.h> |
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#include <linux/interrupt.h> |
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#include <linux/io.h> |
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#include <linux/kernel.h> |
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#include <linux/mfd/syscon.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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#include <linux/regmap.h> |
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#include <linux/types.h> |
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#include <linux/watchdog.h> |
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/* |
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* There are four counters that can be used for watchdog on Armada 37xx. |
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* The addresses for counter control registers are register base plus ID*0x10, |
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* where ID is 0, 1, 2 or 3. |
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* |
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* In this driver we use IDs 0 and 1. Counter ID 1 is used as watchdog counter, |
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* while counter ID 0 is used to implement pinging the watchdog: counter ID 1 is |
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* set to restart counting from initial value on counter ID 0 end count event. |
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* Pinging is done by forcing immediate end count event on counter ID 0. |
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* If only one counter was used, pinging would have to be implemented by |
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* disabling and enabling the counter, leaving the system in a vulnerable state |
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* for a (really) short period of time. |
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* |
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* Counters ID 2 and 3 are enabled by default even before U-Boot loads, |
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* therefore this driver does not provide a way to use them, eg. by setting a |
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* property in device tree. |
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*/ |
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#define CNTR_ID_RETRIGGER 0 |
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#define CNTR_ID_WDOG 1 |
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/* relative to cpu_misc */ |
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#define WDT_TIMER_SELECT 0x64 |
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#define WDT_TIMER_SELECT_MASK 0xf |
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#define WDT_TIMER_SELECT_VAL BIT(CNTR_ID_WDOG) |
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/* relative to reg */ |
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#define CNTR_CTRL(id) ((id) * 0x10) |
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#define CNTR_CTRL_ENABLE 0x0001 |
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#define CNTR_CTRL_ACTIVE 0x0002 |
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#define CNTR_CTRL_MODE_MASK 0x000c |
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#define CNTR_CTRL_MODE_ONESHOT 0x0000 |
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#define CNTR_CTRL_MODE_HWSIG 0x000c |
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#define CNTR_CTRL_TRIG_SRC_MASK 0x00f0 |
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#define CNTR_CTRL_TRIG_SRC_PREV_CNTR 0x0050 |
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#define CNTR_CTRL_PRESCALE_MASK 0xff00 |
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#define CNTR_CTRL_PRESCALE_MIN 2 |
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#define CNTR_CTRL_PRESCALE_SHIFT 8 |
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#define CNTR_COUNT_LOW(id) (CNTR_CTRL(id) + 0x4) |
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#define CNTR_COUNT_HIGH(id) (CNTR_CTRL(id) + 0x8) |
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#define WATCHDOG_TIMEOUT 120 |
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static unsigned int timeout; |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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struct armada_37xx_watchdog { |
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struct watchdog_device wdt; |
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struct regmap *cpu_misc; |
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void __iomem *reg; |
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u64 timeout; /* in clock ticks */ |
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unsigned long clk_rate; |
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struct clk *clk; |
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}; |
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static u64 get_counter_value(struct armada_37xx_watchdog *dev, int id) |
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{ |
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u64 val; |
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/* |
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* when low is read, high is latched into flip-flops so that it can be |
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* read consistently without using software debouncing |
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*/ |
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val = readl(dev->reg + CNTR_COUNT_LOW(id)); |
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val |= ((u64)readl(dev->reg + CNTR_COUNT_HIGH(id))) << 32; |
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return val; |
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} |
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static void set_counter_value(struct armada_37xx_watchdog *dev, int id, u64 val) |
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{ |
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writel(val & 0xffffffff, dev->reg + CNTR_COUNT_LOW(id)); |
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writel(val >> 32, dev->reg + CNTR_COUNT_HIGH(id)); |
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} |
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static void counter_enable(struct armada_37xx_watchdog *dev, int id) |
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{ |
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u32 reg; |
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reg = readl(dev->reg + CNTR_CTRL(id)); |
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reg |= CNTR_CTRL_ENABLE; |
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writel(reg, dev->reg + CNTR_CTRL(id)); |
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} |
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static void counter_disable(struct armada_37xx_watchdog *dev, int id) |
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{ |
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u32 reg; |
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reg = readl(dev->reg + CNTR_CTRL(id)); |
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reg &= ~CNTR_CTRL_ENABLE; |
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writel(reg, dev->reg + CNTR_CTRL(id)); |
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} |
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static void init_counter(struct armada_37xx_watchdog *dev, int id, u32 mode, |
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u32 trig_src) |
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{ |
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u32 reg; |
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reg = readl(dev->reg + CNTR_CTRL(id)); |
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reg &= ~(CNTR_CTRL_MODE_MASK | CNTR_CTRL_PRESCALE_MASK | |
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CNTR_CTRL_TRIG_SRC_MASK); |
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/* set mode */ |
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reg |= mode & CNTR_CTRL_MODE_MASK; |
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/* set prescaler to the min value */ |
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reg |= CNTR_CTRL_PRESCALE_MIN << CNTR_CTRL_PRESCALE_SHIFT; |
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/* set trigger source */ |
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reg |= trig_src & CNTR_CTRL_TRIG_SRC_MASK; |
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writel(reg, dev->reg + CNTR_CTRL(id)); |
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} |
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static int armada_37xx_wdt_ping(struct watchdog_device *wdt) |
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{ |
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struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); |
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/* counter 1 is retriggered by forcing end count on counter 0 */ |
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counter_disable(dev, CNTR_ID_RETRIGGER); |
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counter_enable(dev, CNTR_ID_RETRIGGER); |
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return 0; |
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} |
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static unsigned int armada_37xx_wdt_get_timeleft(struct watchdog_device *wdt) |
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{ |
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struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); |
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u64 res; |
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res = get_counter_value(dev, CNTR_ID_WDOG) * CNTR_CTRL_PRESCALE_MIN; |
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do_div(res, dev->clk_rate); |
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return res; |
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} |
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static int armada_37xx_wdt_set_timeout(struct watchdog_device *wdt, |
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unsigned int timeout) |
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{ |
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struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); |
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wdt->timeout = timeout; |
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/* |
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* Compute the timeout in clock rate. We use smallest possible |
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* prescaler, which divides the clock rate by 2 |
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* (CNTR_CTRL_PRESCALE_MIN). |
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*/ |
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dev->timeout = (u64)dev->clk_rate * timeout; |
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do_div(dev->timeout, CNTR_CTRL_PRESCALE_MIN); |
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return 0; |
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} |
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static bool armada_37xx_wdt_is_running(struct armada_37xx_watchdog *dev) |
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{ |
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u32 reg; |
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regmap_read(dev->cpu_misc, WDT_TIMER_SELECT, ®); |
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if ((reg & WDT_TIMER_SELECT_MASK) != WDT_TIMER_SELECT_VAL) |
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return false; |
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reg = readl(dev->reg + CNTR_CTRL(CNTR_ID_WDOG)); |
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return !!(reg & CNTR_CTRL_ACTIVE); |
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} |
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static int armada_37xx_wdt_start(struct watchdog_device *wdt) |
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{ |
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struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); |
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/* select counter 1 as watchdog counter */ |
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regmap_write(dev->cpu_misc, WDT_TIMER_SELECT, WDT_TIMER_SELECT_VAL); |
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/* init counter 0 as retrigger counter for counter 1 */ |
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init_counter(dev, CNTR_ID_RETRIGGER, CNTR_CTRL_MODE_ONESHOT, 0); |
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set_counter_value(dev, CNTR_ID_RETRIGGER, 0); |
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/* init counter 1 to be retriggerable by counter 0 end count */ |
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init_counter(dev, CNTR_ID_WDOG, CNTR_CTRL_MODE_HWSIG, |
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CNTR_CTRL_TRIG_SRC_PREV_CNTR); |
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set_counter_value(dev, CNTR_ID_WDOG, dev->timeout); |
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/* enable counter 1 */ |
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counter_enable(dev, CNTR_ID_WDOG); |
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/* start counter 1 by forcing immediate end count on counter 0 */ |
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counter_enable(dev, CNTR_ID_RETRIGGER); |
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return 0; |
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} |
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static int armada_37xx_wdt_stop(struct watchdog_device *wdt) |
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{ |
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struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); |
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counter_disable(dev, CNTR_ID_WDOG); |
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counter_disable(dev, CNTR_ID_RETRIGGER); |
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regmap_write(dev->cpu_misc, WDT_TIMER_SELECT, 0); |
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return 0; |
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} |
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static const struct watchdog_info armada_37xx_wdt_info = { |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
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.identity = "Armada 37xx Watchdog", |
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}; |
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static const struct watchdog_ops armada_37xx_wdt_ops = { |
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.owner = THIS_MODULE, |
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.start = armada_37xx_wdt_start, |
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.stop = armada_37xx_wdt_stop, |
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.ping = armada_37xx_wdt_ping, |
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.set_timeout = armada_37xx_wdt_set_timeout, |
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.get_timeleft = armada_37xx_wdt_get_timeleft, |
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}; |
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static void armada_clk_disable_unprepare(void *data) |
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{ |
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clk_disable_unprepare(data); |
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} |
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static int armada_37xx_wdt_probe(struct platform_device *pdev) |
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{ |
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struct armada_37xx_watchdog *dev; |
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struct resource *res; |
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struct regmap *regmap; |
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int ret; |
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dev = devm_kzalloc(&pdev->dev, sizeof(struct armada_37xx_watchdog), |
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GFP_KERNEL); |
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if (!dev) |
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return -ENOMEM; |
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dev->wdt.info = &armada_37xx_wdt_info; |
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dev->wdt.ops = &armada_37xx_wdt_ops; |
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regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, |
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"marvell,system-controller"); |
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if (IS_ERR(regmap)) |
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return PTR_ERR(regmap); |
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dev->cpu_misc = regmap; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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if (!res) |
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return -ENODEV; |
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dev->reg = devm_ioremap(&pdev->dev, res->start, resource_size(res)); |
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/* init clock */ |
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dev->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(dev->clk)) |
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return PTR_ERR(dev->clk); |
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ret = clk_prepare_enable(dev->clk); |
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if (ret) |
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return ret; |
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ret = devm_add_action_or_reset(&pdev->dev, |
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armada_clk_disable_unprepare, dev->clk); |
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if (ret) |
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return ret; |
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dev->clk_rate = clk_get_rate(dev->clk); |
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if (!dev->clk_rate) |
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return -EINVAL; |
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/* |
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* Since the timeout in seconds is given as 32 bit unsigned int, and |
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* the counters hold 64 bit values, even after multiplication by clock |
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* rate the counter can hold timeout of UINT_MAX seconds. |
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*/ |
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dev->wdt.min_timeout = 1; |
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dev->wdt.max_timeout = UINT_MAX; |
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dev->wdt.parent = &pdev->dev; |
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/* default value, possibly override by module parameter or dtb */ |
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dev->wdt.timeout = WATCHDOG_TIMEOUT; |
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watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev); |
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platform_set_drvdata(pdev, &dev->wdt); |
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watchdog_set_drvdata(&dev->wdt, dev); |
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armada_37xx_wdt_set_timeout(&dev->wdt, dev->wdt.timeout); |
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if (armada_37xx_wdt_is_running(dev)) |
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set_bit(WDOG_HW_RUNNING, &dev->wdt.status); |
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watchdog_set_nowayout(&dev->wdt, nowayout); |
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watchdog_stop_on_reboot(&dev->wdt); |
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ret = devm_watchdog_register_device(&pdev->dev, &dev->wdt); |
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if (ret) |
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return ret; |
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dev_info(&pdev->dev, "Initial timeout %d sec%s\n", |
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dev->wdt.timeout, nowayout ? ", nowayout" : ""); |
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return 0; |
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} |
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static int __maybe_unused armada_37xx_wdt_suspend(struct device *dev) |
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{ |
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struct watchdog_device *wdt = dev_get_drvdata(dev); |
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return armada_37xx_wdt_stop(wdt); |
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} |
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static int __maybe_unused armada_37xx_wdt_resume(struct device *dev) |
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{ |
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struct watchdog_device *wdt = dev_get_drvdata(dev); |
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if (watchdog_active(wdt)) |
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return armada_37xx_wdt_start(wdt); |
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return 0; |
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} |
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static const struct dev_pm_ops armada_37xx_wdt_dev_pm_ops = { |
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SET_SYSTEM_SLEEP_PM_OPS(armada_37xx_wdt_suspend, |
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armada_37xx_wdt_resume) |
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}; |
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#ifdef CONFIG_OF |
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static const struct of_device_id armada_37xx_wdt_match[] = { |
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{ .compatible = "marvell,armada-3700-wdt", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, armada_37xx_wdt_match); |
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#endif |
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static struct platform_driver armada_37xx_wdt_driver = { |
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.probe = armada_37xx_wdt_probe, |
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.driver = { |
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.name = "armada_37xx_wdt", |
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.of_match_table = of_match_ptr(armada_37xx_wdt_match), |
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.pm = &armada_37xx_wdt_dev_pm_ops, |
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}, |
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}; |
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module_platform_driver(armada_37xx_wdt_driver); |
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MODULE_AUTHOR("Marek Behun <[email protected]>"); |
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MODULE_DESCRIPTION("Armada 37xx CPU Watchdog"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:armada_37xx_wdt");
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